xref: /netbsd-src/sys/external/bsd/drm2/dist/drm/drm_dp_mst_topology.c (revision f3cfa6f6ce31685c6c4a758bc430e69eb99f50a4)
1 /*	$NetBSD: drm_dp_mst_topology.c,v 1.3 2018/08/27 06:56:02 riastradh Exp $	*/
2 
3 /*
4  * Copyright © 2014 Red Hat
5  *
6  * Permission to use, copy, modify, distribute, and sell this software and its
7  * documentation for any purpose is hereby granted without fee, provided that
8  * the above copyright notice appear in all copies and that both that copyright
9  * notice and this permission notice appear in supporting documentation, and
10  * that the name of the copyright holders not be used in advertising or
11  * publicity pertaining to distribution of the software without specific,
12  * written prior permission.  The copyright holders make no representations
13  * about the suitability of this software for any purpose.  It is provided "as
14  * is" without express or implied warranty.
15  *
16  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
17  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
18  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
19  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
20  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
21  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
22  * OF THIS SOFTWARE.
23  */
24 
25 #include <sys/cdefs.h>
26 __KERNEL_RCSID(0, "$NetBSD: drm_dp_mst_topology.c,v 1.3 2018/08/27 06:56:02 riastradh Exp $");
27 
28 #include <linux/kernel.h>
29 #include <linux/delay.h>
30 #include <linux/init.h>
31 #include <linux/errno.h>
32 #include <linux/sched.h>
33 #include <linux/seq_file.h>
34 #include <linux/i2c.h>
35 #include <linux/device.h>
36 #include <linux/export.h>
37 #include <linux/module.h>
38 #include <drm/drm_dp_mst_helper.h>
39 #include <drm/drmP.h>
40 
41 #include <drm/drm_fixed.h>
42 
43 /**
44  * DOC: dp mst helper
45  *
46  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
47  * protocol. The helpers contain a topology manager and bandwidth manager.
48  * The helpers encapsulate the sending and received of sideband msgs.
49  */
50 #if IS_ENABLED(CONFIG_DEBUG_FS)
51 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
52 				  char *buf);
53 #endif
54 static int test_calc_pbn_mode(void);
55 
56 static void drm_dp_put_port(struct drm_dp_mst_port *port);
57 
58 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
59 				     int id,
60 				     struct drm_dp_payload *payload);
61 
62 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
63 				  struct drm_dp_mst_port *port,
64 				  int offset, int size, u8 *bytes);
65 
66 static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
67 				     struct drm_dp_mst_branch *mstb);
68 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
69 					   struct drm_dp_mst_branch *mstb,
70 					   struct drm_dp_mst_port *port);
71 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
72 				 u8 *guid);
73 
74 static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
75 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
76 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
77 /* sideband msg handling */
78 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
79 {
80 	u8 bitmask = 0x80;
81 	u8 bitshift = 7;
82 	u8 array_index = 0;
83 	int number_of_bits = num_nibbles * 4;
84 	u8 remainder = 0;
85 
86 	while (number_of_bits != 0) {
87 		number_of_bits--;
88 		remainder <<= 1;
89 		remainder |= (data[array_index] & bitmask) >> bitshift;
90 		bitmask >>= 1;
91 		bitshift--;
92 		if (bitmask == 0) {
93 			bitmask = 0x80;
94 			bitshift = 7;
95 			array_index++;
96 		}
97 		if ((remainder & 0x10) == 0x10)
98 			remainder ^= 0x13;
99 	}
100 
101 	number_of_bits = 4;
102 	while (number_of_bits != 0) {
103 		number_of_bits--;
104 		remainder <<= 1;
105 		if ((remainder & 0x10) != 0)
106 			remainder ^= 0x13;
107 	}
108 
109 	return remainder;
110 }
111 
112 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
113 {
114 	u8 bitmask = 0x80;
115 	u8 bitshift = 7;
116 	u8 array_index = 0;
117 	int number_of_bits = number_of_bytes * 8;
118 	u16 remainder = 0;
119 
120 	while (number_of_bits != 0) {
121 		number_of_bits--;
122 		remainder <<= 1;
123 		remainder |= (data[array_index] & bitmask) >> bitshift;
124 		bitmask >>= 1;
125 		bitshift--;
126 		if (bitmask == 0) {
127 			bitmask = 0x80;
128 			bitshift = 7;
129 			array_index++;
130 		}
131 		if ((remainder & 0x100) == 0x100)
132 			remainder ^= 0xd5;
133 	}
134 
135 	number_of_bits = 8;
136 	while (number_of_bits != 0) {
137 		number_of_bits--;
138 		remainder <<= 1;
139 		if ((remainder & 0x100) != 0)
140 			remainder ^= 0xd5;
141 	}
142 
143 	return remainder & 0xff;
144 }
145 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
146 {
147 	u8 size = 3;
148 	size += (hdr->lct / 2);
149 	return size;
150 }
151 
152 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
153 					   u8 *buf, int *len)
154 {
155 	int idx = 0;
156 	int i;
157 	u8 crc4;
158 	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
159 	for (i = 0; i < (hdr->lct / 2); i++)
160 		buf[idx++] = hdr->rad[i];
161 	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
162 		(hdr->msg_len & 0x3f);
163 	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
164 
165 	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
166 	buf[idx - 1] |= (crc4 & 0xf);
167 
168 	*len = idx;
169 }
170 
171 static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
172 					   u8 *buf, int buflen, u8 *hdrlen)
173 {
174 	u8 crc4;
175 	u8 len;
176 	int i;
177 	u8 idx;
178 	if (buf[0] == 0)
179 		return false;
180 	len = 3;
181 	len += ((buf[0] & 0xf0) >> 4) / 2;
182 	if (len > buflen)
183 		return false;
184 	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
185 
186 	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
187 		DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
188 		return false;
189 	}
190 
191 	hdr->lct = (buf[0] & 0xf0) >> 4;
192 	hdr->lcr = (buf[0] & 0xf);
193 	idx = 1;
194 	for (i = 0; i < (hdr->lct / 2); i++)
195 		hdr->rad[i] = buf[idx++];
196 	hdr->broadcast = (buf[idx] >> 7) & 0x1;
197 	hdr->path_msg = (buf[idx] >> 6) & 0x1;
198 	hdr->msg_len = buf[idx] & 0x3f;
199 	idx++;
200 	hdr->somt = (buf[idx] >> 7) & 0x1;
201 	hdr->eomt = (buf[idx] >> 6) & 0x1;
202 	hdr->seqno = (buf[idx] >> 4) & 0x1;
203 	idx++;
204 	*hdrlen = idx;
205 	return true;
206 }
207 
208 static void drm_dp_encode_sideband_req(struct drm_dp_sideband_msg_req_body *req,
209 				       struct drm_dp_sideband_msg_tx *raw)
210 {
211 	int idx = 0;
212 	int i;
213 	u8 *buf = raw->msg;
214 	buf[idx++] = req->req_type & 0x7f;
215 
216 	switch (req->req_type) {
217 	case DP_ENUM_PATH_RESOURCES:
218 		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
219 		idx++;
220 		break;
221 	case DP_ALLOCATE_PAYLOAD:
222 		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
223 			(req->u.allocate_payload.number_sdp_streams & 0xf);
224 		idx++;
225 		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
226 		idx++;
227 		buf[idx] = (req->u.allocate_payload.pbn >> 8);
228 		idx++;
229 		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
230 		idx++;
231 		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
232 			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
233 				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
234 			idx++;
235 		}
236 		if (req->u.allocate_payload.number_sdp_streams & 1) {
237 			i = req->u.allocate_payload.number_sdp_streams - 1;
238 			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
239 			idx++;
240 		}
241 		break;
242 	case DP_QUERY_PAYLOAD:
243 		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
244 		idx++;
245 		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
246 		idx++;
247 		break;
248 	case DP_REMOTE_DPCD_READ:
249 		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
250 		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
251 		idx++;
252 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
253 		idx++;
254 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
255 		idx++;
256 		buf[idx] = (req->u.dpcd_read.num_bytes);
257 		idx++;
258 		break;
259 
260 	case DP_REMOTE_DPCD_WRITE:
261 		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
262 		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
263 		idx++;
264 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
265 		idx++;
266 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
267 		idx++;
268 		buf[idx] = (req->u.dpcd_write.num_bytes);
269 		idx++;
270 		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
271 		idx += req->u.dpcd_write.num_bytes;
272 		break;
273 	case DP_REMOTE_I2C_READ:
274 		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
275 		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
276 		idx++;
277 		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
278 			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
279 			idx++;
280 			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
281 			idx++;
282 			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
283 			idx += req->u.i2c_read.transactions[i].num_bytes;
284 
285 			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 5;
286 			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
287 			idx++;
288 		}
289 		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
290 		idx++;
291 		buf[idx] = (req->u.i2c_read.num_bytes_read);
292 		idx++;
293 		break;
294 
295 	case DP_REMOTE_I2C_WRITE:
296 		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
297 		idx++;
298 		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
299 		idx++;
300 		buf[idx] = (req->u.i2c_write.num_bytes);
301 		idx++;
302 		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
303 		idx += req->u.i2c_write.num_bytes;
304 		break;
305 	}
306 	raw->cur_len = idx;
307 }
308 
309 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
310 {
311 	u8 crc4;
312 	crc4 = drm_dp_msg_data_crc4(msg, len);
313 	msg[len] = crc4;
314 }
315 
316 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
317 					 struct drm_dp_sideband_msg_tx *raw)
318 {
319 	int idx = 0;
320 	u8 *buf = raw->msg;
321 
322 	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
323 
324 	raw->cur_len = idx;
325 }
326 
327 /* this adds a chunk of msg to the builder to get the final msg */
328 static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
329 				      u8 *replybuf, u8 replybuflen, bool hdr)
330 {
331 	int ret;
332 	u8 crc4 __unused;	/* XXX Mistake?  */
333 
334 	if (hdr) {
335 		u8 hdrlen;
336 		struct drm_dp_sideband_msg_hdr recv_hdr;
337 		ret = drm_dp_decode_sideband_msg_hdr(&recv_hdr, replybuf, replybuflen, &hdrlen);
338 		if (ret == false) {
339 			print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, 1, replybuf, replybuflen, false);
340 			return false;
341 		}
342 
343 		/*
344 		 * ignore out-of-order messages or messages that are part of a
345 		 * failed transaction
346 		 */
347 		if (!recv_hdr.somt && !msg->have_somt)
348 			return false;
349 
350 		/* get length contained in this portion */
351 		msg->curchunk_len = recv_hdr.msg_len;
352 		msg->curchunk_hdrlen = hdrlen;
353 
354 		/* we have already gotten an somt - don't bother parsing */
355 		if (recv_hdr.somt && msg->have_somt)
356 			return false;
357 
358 		if (recv_hdr.somt) {
359 			memcpy(&msg->initial_hdr, &recv_hdr, sizeof(struct drm_dp_sideband_msg_hdr));
360 			msg->have_somt = true;
361 		}
362 		if (recv_hdr.eomt)
363 			msg->have_eomt = true;
364 
365 		/* copy the bytes for the remainder of this header chunk */
366 		msg->curchunk_idx = min(msg->curchunk_len, (u8)(replybuflen - hdrlen));
367 		memcpy(&msg->chunk[0], replybuf + hdrlen, msg->curchunk_idx);
368 	} else {
369 		memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
370 		msg->curchunk_idx += replybuflen;
371 	}
372 
373 	if (msg->curchunk_idx >= msg->curchunk_len) {
374 		/* do CRC */
375 		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
376 		/* copy chunk into bigger msg */
377 		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
378 		msg->curlen += msg->curchunk_len - 1;
379 	}
380 	return true;
381 }
382 
383 static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
384 					       struct drm_dp_sideband_msg_reply_body *repmsg)
385 {
386 	int idx = 1;
387 	int i;
388 	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
389 	idx += 16;
390 	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
391 	idx++;
392 	if (idx > raw->curlen)
393 		goto fail_len;
394 	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
395 		if (raw->msg[idx] & 0x80)
396 			repmsg->u.link_addr.ports[i].input_port = 1;
397 
398 		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
399 		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
400 
401 		idx++;
402 		if (idx > raw->curlen)
403 			goto fail_len;
404 		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
405 		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
406 		if (repmsg->u.link_addr.ports[i].input_port == 0)
407 			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
408 		idx++;
409 		if (idx > raw->curlen)
410 			goto fail_len;
411 		if (repmsg->u.link_addr.ports[i].input_port == 0) {
412 			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
413 			idx++;
414 			if (idx > raw->curlen)
415 				goto fail_len;
416 			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
417 			idx += 16;
418 			if (idx > raw->curlen)
419 				goto fail_len;
420 			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
421 			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
422 			idx++;
423 
424 		}
425 		if (idx > raw->curlen)
426 			goto fail_len;
427 	}
428 
429 	return true;
430 fail_len:
431 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
432 	return false;
433 }
434 
435 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
436 						   struct drm_dp_sideband_msg_reply_body *repmsg)
437 {
438 	int idx = 1;
439 	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
440 	idx++;
441 	if (idx > raw->curlen)
442 		goto fail_len;
443 	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
444 	if (idx > raw->curlen)
445 		goto fail_len;
446 
447 	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
448 	return true;
449 fail_len:
450 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
451 	return false;
452 }
453 
454 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
455 						      struct drm_dp_sideband_msg_reply_body *repmsg)
456 {
457 	int idx = 1;
458 	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
459 	idx++;
460 	if (idx > raw->curlen)
461 		goto fail_len;
462 	return true;
463 fail_len:
464 	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
465 	return false;
466 }
467 
468 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
469 						      struct drm_dp_sideband_msg_reply_body *repmsg)
470 {
471 	int idx = 1;
472 
473 	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
474 	idx++;
475 	if (idx > raw->curlen)
476 		goto fail_len;
477 	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
478 	idx++;
479 	/* TODO check */
480 	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
481 	return true;
482 fail_len:
483 	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
484 	return false;
485 }
486 
487 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
488 							  struct drm_dp_sideband_msg_reply_body *repmsg)
489 {
490 	int idx = 1;
491 	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
492 	idx++;
493 	if (idx > raw->curlen)
494 		goto fail_len;
495 	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
496 	idx += 2;
497 	if (idx > raw->curlen)
498 		goto fail_len;
499 	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
500 	idx += 2;
501 	if (idx > raw->curlen)
502 		goto fail_len;
503 	return true;
504 fail_len:
505 	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
506 	return false;
507 }
508 
509 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
510 							  struct drm_dp_sideband_msg_reply_body *repmsg)
511 {
512 	int idx = 1;
513 	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
514 	idx++;
515 	if (idx > raw->curlen)
516 		goto fail_len;
517 	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
518 	idx++;
519 	if (idx > raw->curlen)
520 		goto fail_len;
521 	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
522 	idx += 2;
523 	if (idx > raw->curlen)
524 		goto fail_len;
525 	return true;
526 fail_len:
527 	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
528 	return false;
529 }
530 
531 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
532 						    struct drm_dp_sideband_msg_reply_body *repmsg)
533 {
534 	int idx = 1;
535 	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
536 	idx++;
537 	if (idx > raw->curlen)
538 		goto fail_len;
539 	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
540 	idx += 2;
541 	if (idx > raw->curlen)
542 		goto fail_len;
543 	return true;
544 fail_len:
545 	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
546 	return false;
547 }
548 
549 static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
550 					struct drm_dp_sideband_msg_reply_body *msg)
551 {
552 	memset(msg, 0, sizeof(*msg));
553 	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
554 	msg->req_type = (raw->msg[0] & 0x7f);
555 
556 	if (msg->reply_type) {
557 		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
558 		msg->u.nak.reason = raw->msg[17];
559 		msg->u.nak.nak_data = raw->msg[18];
560 		return false;
561 	}
562 
563 	switch (msg->req_type) {
564 	case DP_LINK_ADDRESS:
565 		return drm_dp_sideband_parse_link_address(raw, msg);
566 	case DP_QUERY_PAYLOAD:
567 		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
568 	case DP_REMOTE_DPCD_READ:
569 		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
570 	case DP_REMOTE_DPCD_WRITE:
571 		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
572 	case DP_REMOTE_I2C_READ:
573 		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
574 	case DP_ENUM_PATH_RESOURCES:
575 		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
576 	case DP_ALLOCATE_PAYLOAD:
577 		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
578 	default:
579 		DRM_ERROR("Got unknown reply 0x%02x\n", msg->req_type);
580 		return false;
581 	}
582 }
583 
584 static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
585 							   struct drm_dp_sideband_msg_req_body *msg)
586 {
587 	int idx = 1;
588 
589 	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
590 	idx++;
591 	if (idx > raw->curlen)
592 		goto fail_len;
593 
594 	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
595 	idx += 16;
596 	if (idx > raw->curlen)
597 		goto fail_len;
598 
599 	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
600 	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
601 	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
602 	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
603 	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
604 	idx++;
605 	return true;
606 fail_len:
607 	DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
608 	return false;
609 }
610 
611 static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
612 							   struct drm_dp_sideband_msg_req_body *msg)
613 {
614 	int idx = 1;
615 
616 	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
617 	idx++;
618 	if (idx > raw->curlen)
619 		goto fail_len;
620 
621 	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
622 	idx += 16;
623 	if (idx > raw->curlen)
624 		goto fail_len;
625 
626 	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
627 	idx++;
628 	return true;
629 fail_len:
630 	DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
631 	return false;
632 }
633 
634 static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
635 				      struct drm_dp_sideband_msg_req_body *msg)
636 {
637 	memset(msg, 0, sizeof(*msg));
638 	msg->req_type = (raw->msg[0] & 0x7f);
639 
640 	switch (msg->req_type) {
641 	case DP_CONNECTION_STATUS_NOTIFY:
642 		return drm_dp_sideband_parse_connection_status_notify(raw, msg);
643 	case DP_RESOURCE_STATUS_NOTIFY:
644 		return drm_dp_sideband_parse_resource_status_notify(raw, msg);
645 	default:
646 		DRM_ERROR("Got unknown request 0x%02x\n", msg->req_type);
647 		return false;
648 	}
649 }
650 
651 static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
652 {
653 	struct drm_dp_sideband_msg_req_body req;
654 
655 	req.req_type = DP_REMOTE_DPCD_WRITE;
656 	req.u.dpcd_write.port_number = port_num;
657 	req.u.dpcd_write.dpcd_address = offset;
658 	req.u.dpcd_write.num_bytes = num_bytes;
659 	req.u.dpcd_write.bytes = bytes;
660 	drm_dp_encode_sideband_req(&req, msg);
661 
662 	return 0;
663 }
664 
665 static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
666 {
667 	struct drm_dp_sideband_msg_req_body req;
668 
669 	req.req_type = DP_LINK_ADDRESS;
670 	drm_dp_encode_sideband_req(&req, msg);
671 	return 0;
672 }
673 
674 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
675 {
676 	struct drm_dp_sideband_msg_req_body req;
677 
678 	req.req_type = DP_ENUM_PATH_RESOURCES;
679 	req.u.port_num.port_number = port_num;
680 	drm_dp_encode_sideband_req(&req, msg);
681 	msg->path_msg = true;
682 	return 0;
683 }
684 
685 static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
686 				  u8 vcpi, uint16_t pbn)
687 {
688 	struct drm_dp_sideband_msg_req_body req;
689 	memset(&req, 0, sizeof(req));
690 	req.req_type = DP_ALLOCATE_PAYLOAD;
691 	req.u.allocate_payload.port_number = port_num;
692 	req.u.allocate_payload.vcpi = vcpi;
693 	req.u.allocate_payload.pbn = pbn;
694 	drm_dp_encode_sideband_req(&req, msg);
695 	msg->path_msg = true;
696 	return 0;
697 }
698 
699 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
700 					struct drm_dp_vcpi *vcpi)
701 {
702 	int ret, vcpi_ret;
703 
704 	mutex_lock(&mgr->payload_lock);
705 	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
706 	if (ret > mgr->max_payloads) {
707 		ret = -EINVAL;
708 		DRM_DEBUG_KMS("out of payload ids %d\n", ret);
709 		goto out_unlock;
710 	}
711 
712 	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
713 	if (vcpi_ret > mgr->max_payloads) {
714 		ret = -EINVAL;
715 		DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
716 		goto out_unlock;
717 	}
718 
719 	set_bit(ret, &mgr->payload_mask);
720 	set_bit(vcpi_ret, &mgr->vcpi_mask);
721 	vcpi->vcpi = vcpi_ret + 1;
722 	mgr->proposed_vcpis[ret - 1] = vcpi;
723 out_unlock:
724 	mutex_unlock(&mgr->payload_lock);
725 	return ret;
726 }
727 
728 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
729 				      int vcpi)
730 {
731 	int i;
732 	if (vcpi == 0)
733 		return;
734 
735 	mutex_lock(&mgr->payload_lock);
736 	DRM_DEBUG_KMS("putting payload %d\n", vcpi);
737 	clear_bit(vcpi - 1, &mgr->vcpi_mask);
738 
739 	for (i = 0; i < mgr->max_payloads; i++) {
740 		if (mgr->proposed_vcpis[i])
741 			if (mgr->proposed_vcpis[i]->vcpi == vcpi) {
742 				mgr->proposed_vcpis[i] = NULL;
743 				clear_bit(i + 1, &mgr->payload_mask);
744 			}
745 	}
746 	mutex_unlock(&mgr->payload_lock);
747 }
748 
749 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
750 			      struct drm_dp_sideband_msg_tx *txmsg)
751 {
752 	bool ret;
753 
754 	/*
755 	 * All updates to txmsg->state are protected by mgr->qlock, and the two
756 	 * cases we check here are terminal states. For those the barriers
757 	 * provided by the wake_up/wait_event pair are enough.
758 	 */
759 	ret = (txmsg->state == DRM_DP_SIDEBAND_TX_RX ||
760 	       txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT);
761 	return ret;
762 }
763 
764 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
765 				    struct drm_dp_sideband_msg_tx *txmsg)
766 {
767 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
768 	int ret;
769 
770 #ifdef __NetBSD__
771 	mutex_lock(&mstb->mgr->qlock);
772 	DRM_TIMED_WAIT_UNTIL(ret, &mgr->tx_waitq, &mstb->mgr->qlock, 4*HZ,
773 	    check_txmsg_state(mgr, txmsg));
774 #else
775 	ret = wait_event_timeout(mgr->tx_waitq,
776 				 check_txmsg_state(mgr, txmsg),
777 				 (4 * HZ));
778 	mutex_lock(&mstb->mgr->qlock);
779 #endif
780 	if (ret > 0) {
781 		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
782 			ret = -EIO;
783 			goto out;
784 		}
785 	} else {
786 		DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
787 
788 		/* dump some state */
789 		ret = -EIO;
790 
791 		/* remove from q */
792 		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
793 		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND) {
794 			list_del(&txmsg->next);
795 		}
796 
797 		if (txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
798 		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
799 			mstb->tx_slots[txmsg->seqno] = NULL;
800 		}
801 	}
802 out:
803 	mutex_unlock(&mgr->qlock);
804 
805 	return ret;
806 }
807 
808 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
809 {
810 	struct drm_dp_mst_branch *mstb;
811 
812 	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
813 	if (!mstb)
814 		return NULL;
815 
816 	mstb->lct = lct;
817 	if (lct > 1)
818 		memcpy(mstb->rad, rad, lct / 2);
819 	INIT_LIST_HEAD(&mstb->ports);
820 	kref_init(&mstb->kref);
821 	return mstb;
822 }
823 
824 static void drm_dp_free_mst_port(struct kref *kref);
825 
826 static void drm_dp_free_mst_branch_device(struct kref *kref)
827 {
828 	struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
829 	if (mstb->port_parent) {
830 		if (list_empty(&mstb->port_parent->next))
831 			kref_put(&mstb->port_parent->kref, drm_dp_free_mst_port);
832 	}
833 	kfree(mstb);
834 }
835 
836 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
837 {
838 	struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
839 	struct drm_dp_mst_port *port, *tmp;
840 	bool wake_tx = false;
841 
842 	/*
843 	 * init kref again to be used by ports to remove mst branch when it is
844 	 * not needed anymore
845 	 */
846 	kref_init(kref);
847 
848 	if (mstb->port_parent && list_empty(&mstb->port_parent->next))
849 		kref_get(&mstb->port_parent->kref);
850 
851 	/*
852 	 * destroy all ports - don't need lock
853 	 * as there are no more references to the mst branch
854 	 * device at this point.
855 	 */
856 	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
857 		list_del(&port->next);
858 		drm_dp_put_port(port);
859 	}
860 
861 	/* drop any tx slots msg */
862 	mutex_lock(&mstb->mgr->qlock);
863 	if (mstb->tx_slots[0]) {
864 		mstb->tx_slots[0]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
865 		mstb->tx_slots[0] = NULL;
866 		wake_tx = true;
867 	}
868 	if (mstb->tx_slots[1]) {
869 		mstb->tx_slots[1]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
870 		mstb->tx_slots[1] = NULL;
871 		wake_tx = true;
872 	}
873 #ifdef __NetBSD__
874 	if (wake_tx)
875 		DRM_WAKEUP_ONE(&mstb->mgr->tx_waitq, &mstb->mgr->qlock);
876 	mutex_unlock(&mstb->mgr->qlock);
877 #else
878 	mutex_unlock(&mstb->mgr->qlock);
879 
880 	if (wake_tx)
881 		wake_up(&mstb->mgr->tx_waitq);
882 #endif
883 
884 	kref_put(kref, drm_dp_free_mst_branch_device);
885 }
886 
887 static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb)
888 {
889 	kref_put(&mstb->kref, drm_dp_destroy_mst_branch_device);
890 }
891 
892 
893 static void drm_dp_port_teardown_pdt(struct drm_dp_mst_port *port, int old_pdt)
894 {
895 	struct drm_dp_mst_branch *mstb;
896 
897 	switch (old_pdt) {
898 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
899 	case DP_PEER_DEVICE_SST_SINK:
900 		/* remove i2c over sideband */
901 		drm_dp_mst_unregister_i2c_bus(&port->aux);
902 		break;
903 	case DP_PEER_DEVICE_MST_BRANCHING:
904 		mstb = port->mstb;
905 		port->mstb = NULL;
906 		drm_dp_put_mst_branch_device(mstb);
907 		break;
908 	}
909 }
910 
911 static void drm_dp_destroy_port(struct kref *kref)
912 {
913 	struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
914 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
915 
916 	if (!port->input) {
917 		port->vcpi.num_slots = 0;
918 
919 		kfree(port->cached_edid);
920 
921 		/*
922 		 * The only time we don't have a connector
923 		 * on an output port is if the connector init
924 		 * fails.
925 		 */
926 		if (port->connector) {
927 			/* we can't destroy the connector here, as
928 			 * we might be holding the mode_config.mutex
929 			 * from an EDID retrieval */
930 
931 			mutex_lock(&mgr->destroy_connector_lock);
932 			kref_get(&port->parent->kref);
933 			list_add(&port->next, &mgr->destroy_connector_list);
934 			mutex_unlock(&mgr->destroy_connector_lock);
935 			schedule_work(&mgr->destroy_connector_work);
936 			return;
937 		}
938 		/* no need to clean up vcpi
939 		 * as if we have no connector we never setup a vcpi */
940 		drm_dp_port_teardown_pdt(port, port->pdt);
941 		port->pdt = DP_PEER_DEVICE_NONE;
942 	}
943 	kfree(port);
944 }
945 
946 static void drm_dp_put_port(struct drm_dp_mst_port *port)
947 {
948 	kref_put(&port->kref, drm_dp_destroy_port);
949 }
950 
951 static struct drm_dp_mst_branch *drm_dp_mst_get_validated_mstb_ref_locked(struct drm_dp_mst_branch *mstb, struct drm_dp_mst_branch *to_find)
952 {
953 	struct drm_dp_mst_port *port;
954 	struct drm_dp_mst_branch *rmstb;
955 	if (to_find == mstb) {
956 		kref_get(&mstb->kref);
957 		return mstb;
958 	}
959 	list_for_each_entry(port, &mstb->ports, next) {
960 		if (port->mstb) {
961 			rmstb = drm_dp_mst_get_validated_mstb_ref_locked(port->mstb, to_find);
962 			if (rmstb)
963 				return rmstb;
964 		}
965 	}
966 	return NULL;
967 }
968 
969 static struct drm_dp_mst_branch *drm_dp_get_validated_mstb_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_branch *mstb)
970 {
971 	struct drm_dp_mst_branch *rmstb = NULL;
972 	mutex_lock(&mgr->lock);
973 	if (mgr->mst_primary)
974 		rmstb = drm_dp_mst_get_validated_mstb_ref_locked(mgr->mst_primary, mstb);
975 	mutex_unlock(&mgr->lock);
976 	return rmstb;
977 }
978 
979 static struct drm_dp_mst_port *drm_dp_mst_get_port_ref_locked(struct drm_dp_mst_branch *mstb, struct drm_dp_mst_port *to_find)
980 {
981 	struct drm_dp_mst_port *port, *mport;
982 
983 	list_for_each_entry(port, &mstb->ports, next) {
984 		if (port == to_find) {
985 			kref_get(&port->kref);
986 			return port;
987 		}
988 		if (port->mstb) {
989 			mport = drm_dp_mst_get_port_ref_locked(port->mstb, to_find);
990 			if (mport)
991 				return mport;
992 		}
993 	}
994 	return NULL;
995 }
996 
997 static struct drm_dp_mst_port *drm_dp_get_validated_port_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
998 {
999 	struct drm_dp_mst_port *rport = NULL;
1000 	mutex_lock(&mgr->lock);
1001 	if (mgr->mst_primary)
1002 		rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port);
1003 	mutex_unlock(&mgr->lock);
1004 	return rport;
1005 }
1006 
1007 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
1008 {
1009 	struct drm_dp_mst_port *port;
1010 
1011 	list_for_each_entry(port, &mstb->ports, next) {
1012 		if (port->port_num == port_num) {
1013 			kref_get(&port->kref);
1014 			return port;
1015 		}
1016 	}
1017 
1018 	return NULL;
1019 }
1020 
1021 /*
1022  * calculate a new RAD for this MST branch device
1023  * if parent has an LCT of 2 then it has 1 nibble of RAD,
1024  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
1025  */
1026 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
1027 				 u8 *rad)
1028 {
1029 	int parent_lct = port->parent->lct;
1030 	int shift = 4;
1031 	int idx = (parent_lct - 1) / 2;
1032 	if (parent_lct > 1) {
1033 		memcpy(rad, port->parent->rad, idx + 1);
1034 		shift = (parent_lct % 2) ? 4 : 0;
1035 	} else
1036 		rad[0] = 0;
1037 
1038 	rad[idx] |= port->port_num << shift;
1039 	return parent_lct + 1;
1040 }
1041 
1042 /*
1043  * return sends link address for new mstb
1044  */
1045 static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
1046 {
1047 	int ret __unused;
1048 	u8 rad[6], lct;
1049 	bool send_link = false;
1050 	switch (port->pdt) {
1051 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
1052 	case DP_PEER_DEVICE_SST_SINK:
1053 		/* add i2c over sideband */
1054 		ret = drm_dp_mst_register_i2c_bus(&port->aux);
1055 		break;
1056 	case DP_PEER_DEVICE_MST_BRANCHING:
1057 		lct = drm_dp_calculate_rad(port, rad);
1058 
1059 		port->mstb = drm_dp_add_mst_branch_device(lct, rad);
1060 		port->mstb->mgr = port->mgr;
1061 		port->mstb->port_parent = port;
1062 
1063 		send_link = true;
1064 		break;
1065 	}
1066 	return send_link;
1067 }
1068 
1069 static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
1070 {
1071 	int ret __unused;
1072 
1073 	memcpy(mstb->guid, guid, 16);
1074 
1075 	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
1076 		if (mstb->port_parent) {
1077 			ret = drm_dp_send_dpcd_write(
1078 					mstb->mgr,
1079 					mstb->port_parent,
1080 					DP_GUID,
1081 					16,
1082 					mstb->guid);
1083 		} else {
1084 
1085 			ret = drm_dp_dpcd_write(
1086 					mstb->mgr->aux,
1087 					DP_GUID,
1088 					mstb->guid,
1089 					16);
1090 		}
1091 	}
1092 }
1093 
1094 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
1095 				int pnum,
1096 				char *proppath,
1097 				size_t proppath_size)
1098 {
1099 	int i;
1100 	char temp[8];
1101 	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
1102 	for (i = 0; i < (mstb->lct - 1); i++) {
1103 		int shift = (i % 2) ? 0 : 4;
1104 		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
1105 		snprintf(temp, sizeof(temp), "-%d", port_num);
1106 		strlcat(proppath, temp, proppath_size);
1107 	}
1108 	snprintf(temp, sizeof(temp), "-%d", pnum);
1109 	strlcat(proppath, temp, proppath_size);
1110 }
1111 
1112 static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
1113 			    struct device *dev,
1114 			    struct drm_dp_link_addr_reply_port *port_msg)
1115 {
1116 	struct drm_dp_mst_port *port;
1117 	bool ret;
1118 	bool created = false;
1119 	int old_pdt = 0;
1120 	int old_ddps = 0;
1121 	port = drm_dp_get_port(mstb, port_msg->port_number);
1122 	if (!port) {
1123 		port = kzalloc(sizeof(*port), GFP_KERNEL);
1124 		if (!port)
1125 			return;
1126 		kref_init(&port->kref);
1127 		port->parent = mstb;
1128 		port->port_num = port_msg->port_number;
1129 		port->mgr = mstb->mgr;
1130 		port->aux.name = "DPMST";
1131 		port->aux.dev = dev;
1132 		created = true;
1133 	} else {
1134 		old_pdt = port->pdt;
1135 		old_ddps = port->ddps;
1136 	}
1137 
1138 	port->pdt = port_msg->peer_device_type;
1139 	port->input = port_msg->input_port;
1140 	port->mcs = port_msg->mcs;
1141 	port->ddps = port_msg->ddps;
1142 	port->ldps = port_msg->legacy_device_plug_status;
1143 	port->dpcd_rev = port_msg->dpcd_revision;
1144 	port->num_sdp_streams = port_msg->num_sdp_streams;
1145 	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
1146 
1147 	/* manage mstb port lists with mgr lock - take a reference
1148 	   for this list */
1149 	if (created) {
1150 		mutex_lock(&mstb->mgr->lock);
1151 		kref_get(&port->kref);
1152 		list_add(&port->next, &mstb->ports);
1153 		mutex_unlock(&mstb->mgr->lock);
1154 	}
1155 
1156 	if (old_ddps != port->ddps) {
1157 		if (port->ddps) {
1158 			if (!port->input)
1159 				drm_dp_send_enum_path_resources(mstb->mgr, mstb, port);
1160 		} else {
1161 			port->available_pbn = 0;
1162 			}
1163 	}
1164 
1165 	if (old_pdt != port->pdt && !port->input) {
1166 		drm_dp_port_teardown_pdt(port, old_pdt);
1167 
1168 		ret = drm_dp_port_setup_pdt(port);
1169 		if (ret == true)
1170 			drm_dp_send_link_address(mstb->mgr, port->mstb);
1171 	}
1172 
1173 	if (created && !port->input) {
1174 		char proppath[255];
1175 
1176 		build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
1177 		port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, proppath);
1178 		if (!port->connector) {
1179 			/* remove it from the port list */
1180 			mutex_lock(&mstb->mgr->lock);
1181 			list_del(&port->next);
1182 			mutex_unlock(&mstb->mgr->lock);
1183 			/* drop port list reference */
1184 			drm_dp_put_port(port);
1185 			goto out;
1186 		}
1187 		if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||
1188 		     port->pdt == DP_PEER_DEVICE_SST_SINK) &&
1189 		    port->port_num >= DP_MST_LOGICAL_PORT_0) {
1190 			port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
1191 			drm_mode_connector_set_tile_property(port->connector);
1192 		}
1193 		(*mstb->mgr->cbs->register_connector)(port->connector);
1194 	}
1195 
1196 out:
1197 	/* put reference to this port */
1198 	drm_dp_put_port(port);
1199 }
1200 
1201 static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
1202 			       struct drm_dp_connection_status_notify *conn_stat)
1203 {
1204 	struct drm_dp_mst_port *port;
1205 	int old_pdt;
1206 	int old_ddps;
1207 	bool dowork = false;
1208 	port = drm_dp_get_port(mstb, conn_stat->port_number);
1209 	if (!port)
1210 		return;
1211 
1212 	old_ddps = port->ddps;
1213 	old_pdt = port->pdt;
1214 	port->pdt = conn_stat->peer_device_type;
1215 	port->mcs = conn_stat->message_capability_status;
1216 	port->ldps = conn_stat->legacy_device_plug_status;
1217 	port->ddps = conn_stat->displayport_device_plug_status;
1218 
1219 	if (old_ddps != port->ddps) {
1220 		if (port->ddps) {
1221 			dowork = true;
1222 		} else {
1223 			port->available_pbn = 0;
1224 		}
1225 	}
1226 	if (old_pdt != port->pdt && !port->input) {
1227 		drm_dp_port_teardown_pdt(port, old_pdt);
1228 
1229 		if (drm_dp_port_setup_pdt(port))
1230 			dowork = true;
1231 	}
1232 
1233 	drm_dp_put_port(port);
1234 	if (dowork)
1235 		queue_work(system_long_wq, &mstb->mgr->work);
1236 
1237 }
1238 
1239 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
1240 							       u8 lct, u8 *rad)
1241 {
1242 	struct drm_dp_mst_branch *mstb;
1243 	struct drm_dp_mst_port *port;
1244 	int i;
1245 	/* find the port by iterating down */
1246 
1247 	mutex_lock(&mgr->lock);
1248 	mstb = mgr->mst_primary;
1249 
1250 	for (i = 0; i < lct - 1; i++) {
1251 		int shift = (i % 2) ? 0 : 4;
1252 		int port_num = (rad[i / 2] >> shift) & 0xf;
1253 
1254 		list_for_each_entry(port, &mstb->ports, next) {
1255 			if (port->port_num == port_num) {
1256 				mstb = port->mstb;
1257 				if (!mstb) {
1258 					DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
1259 					goto out;
1260 				}
1261 
1262 				break;
1263 			}
1264 		}
1265 	}
1266 	kref_get(&mstb->kref);
1267 out:
1268 	mutex_unlock(&mgr->lock);
1269 	return mstb;
1270 }
1271 
1272 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
1273 	struct drm_dp_mst_branch *mstb,
1274 	uint8_t *guid)
1275 {
1276 	struct drm_dp_mst_branch *found_mstb;
1277 	struct drm_dp_mst_port *port;
1278 
1279 	if (memcmp(mstb->guid, guid, 16) == 0)
1280 		return mstb;
1281 
1282 
1283 	list_for_each_entry(port, &mstb->ports, next) {
1284 		if (!port->mstb)
1285 			continue;
1286 
1287 		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
1288 
1289 		if (found_mstb)
1290 			return found_mstb;
1291 	}
1292 
1293 	return NULL;
1294 }
1295 
1296 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid(
1297 	struct drm_dp_mst_topology_mgr *mgr,
1298 	uint8_t *guid)
1299 {
1300 	struct drm_dp_mst_branch *mstb;
1301 
1302 	/* find the port by iterating down */
1303 	mutex_lock(&mgr->lock);
1304 
1305 	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
1306 
1307 	if (mstb)
1308 		kref_get(&mstb->kref);
1309 
1310 	mutex_unlock(&mgr->lock);
1311 	return mstb;
1312 }
1313 
1314 static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1315 					       struct drm_dp_mst_branch *mstb)
1316 {
1317 	struct drm_dp_mst_port *port;
1318 	struct drm_dp_mst_branch *mstb_child;
1319 	if (!mstb->link_address_sent)
1320 		drm_dp_send_link_address(mgr, mstb);
1321 
1322 	list_for_each_entry(port, &mstb->ports, next) {
1323 		if (port->input)
1324 			continue;
1325 
1326 		if (!port->ddps)
1327 			continue;
1328 
1329 		if (!port->available_pbn)
1330 			drm_dp_send_enum_path_resources(mgr, mstb, port);
1331 
1332 		if (port->mstb) {
1333 			mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb);
1334 			if (mstb_child) {
1335 				drm_dp_check_and_send_link_address(mgr, mstb_child);
1336 				drm_dp_put_mst_branch_device(mstb_child);
1337 			}
1338 		}
1339 	}
1340 }
1341 
1342 static void drm_dp_mst_link_probe_work(struct work_struct *work)
1343 {
1344 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
1345 	struct drm_dp_mst_branch *mstb;
1346 
1347 	mutex_lock(&mgr->lock);
1348 	mstb = mgr->mst_primary;
1349 	if (mstb) {
1350 		kref_get(&mstb->kref);
1351 	}
1352 	mutex_unlock(&mgr->lock);
1353 	if (mstb) {
1354 		drm_dp_check_and_send_link_address(mgr, mstb);
1355 		drm_dp_put_mst_branch_device(mstb);
1356 	}
1357 }
1358 
1359 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
1360 				 u8 *guid)
1361 {
1362 	static u8 zero_guid[16];
1363 
1364 	if (!memcmp(guid, zero_guid, 16)) {
1365 		u64 salt = get_jiffies_64();
1366 		memcpy(&guid[0], &salt, sizeof(u64));
1367 		memcpy(&guid[8], &salt, sizeof(u64));
1368 		return false;
1369 	}
1370 	return true;
1371 }
1372 
1373 #if 0
1374 static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
1375 {
1376 	struct drm_dp_sideband_msg_req_body req;
1377 
1378 	req.req_type = DP_REMOTE_DPCD_READ;
1379 	req.u.dpcd_read.port_number = port_num;
1380 	req.u.dpcd_read.dpcd_address = offset;
1381 	req.u.dpcd_read.num_bytes = num_bytes;
1382 	drm_dp_encode_sideband_req(&req, msg);
1383 
1384 	return 0;
1385 }
1386 #endif
1387 
1388 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
1389 				    bool up, u8 *msg, int len)
1390 {
1391 	int ret;
1392 	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
1393 	int tosend, total, offset;
1394 	int retries = 0;
1395 
1396 retry:
1397 	total = len;
1398 	offset = 0;
1399 	do {
1400 		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
1401 
1402 		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
1403 					&msg[offset],
1404 					tosend);
1405 		if (ret != tosend) {
1406 			if (ret == -EIO && retries < 5) {
1407 				retries++;
1408 				goto retry;
1409 			}
1410 			DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
1411 
1412 			return -EIO;
1413 		}
1414 		offset += tosend;
1415 		total -= tosend;
1416 	} while (total > 0);
1417 	return 0;
1418 }
1419 
1420 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
1421 				  struct drm_dp_sideband_msg_tx *txmsg)
1422 {
1423 	struct drm_dp_mst_branch *mstb = txmsg->dst;
1424 	u8 req_type;
1425 
1426 	/* both msg slots are full */
1427 	if (txmsg->seqno == -1) {
1428 		if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
1429 			DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
1430 			return -EAGAIN;
1431 		}
1432 		if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
1433 			txmsg->seqno = mstb->last_seqno;
1434 			mstb->last_seqno ^= 1;
1435 		} else if (mstb->tx_slots[0] == NULL)
1436 			txmsg->seqno = 0;
1437 		else
1438 			txmsg->seqno = 1;
1439 		mstb->tx_slots[txmsg->seqno] = txmsg;
1440 	}
1441 
1442 	req_type = txmsg->msg[0] & 0x7f;
1443 	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
1444 		req_type == DP_RESOURCE_STATUS_NOTIFY)
1445 		hdr->broadcast = 1;
1446 	else
1447 		hdr->broadcast = 0;
1448 	hdr->path_msg = txmsg->path_msg;
1449 	hdr->lct = mstb->lct;
1450 	hdr->lcr = mstb->lct - 1;
1451 	if (mstb->lct > 1)
1452 		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
1453 	hdr->seqno = txmsg->seqno;
1454 	return 0;
1455 }
1456 /*
1457  * process a single block of the next message in the sideband queue
1458  */
1459 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1460 				   struct drm_dp_sideband_msg_tx *txmsg,
1461 				   bool up)
1462 {
1463 	u8 chunk[48];
1464 	struct drm_dp_sideband_msg_hdr hdr;
1465 	int len, space, idx, tosend;
1466 	int ret;
1467 
1468 	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
1469 
1470 	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
1471 		txmsg->seqno = -1;
1472 		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
1473 	}
1474 
1475 	/* make hdr from dst mst - for replies use seqno
1476 	   otherwise assign one */
1477 	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
1478 	if (ret < 0)
1479 		return ret;
1480 
1481 	/* amount left to send in this message */
1482 	len = txmsg->cur_len - txmsg->cur_offset;
1483 
1484 	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
1485 	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
1486 
1487 	tosend = min(len, space);
1488 	if (len == txmsg->cur_len)
1489 		hdr.somt = 1;
1490 	if (space >= len)
1491 		hdr.eomt = 1;
1492 
1493 
1494 	hdr.msg_len = tosend + 1;
1495 	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
1496 	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
1497 	/* add crc at end */
1498 	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
1499 	idx += tosend + 1;
1500 
1501 	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
1502 	if (ret) {
1503 		DRM_DEBUG_KMS("sideband msg failed to send\n");
1504 		return ret;
1505 	}
1506 
1507 	txmsg->cur_offset += tosend;
1508 	if (txmsg->cur_offset == txmsg->cur_len) {
1509 		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
1510 		return 1;
1511 	}
1512 	return 0;
1513 }
1514 
1515 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
1516 {
1517 	struct drm_dp_sideband_msg_tx *txmsg;
1518 	int ret;
1519 
1520 	WARN_ON(!mutex_is_locked(&mgr->qlock));
1521 
1522 	/* construct a chunk from the first msg in the tx_msg queue */
1523 	if (list_empty(&mgr->tx_msg_downq)) {
1524 		mgr->tx_down_in_progress = false;
1525 		return;
1526 	}
1527 	mgr->tx_down_in_progress = true;
1528 
1529 	txmsg = list_first_entry(&mgr->tx_msg_downq, struct drm_dp_sideband_msg_tx, next);
1530 	ret = process_single_tx_qlock(mgr, txmsg, false);
1531 	if (ret == 1) {
1532 		/* txmsg is sent it should be in the slots now */
1533 		list_del(&txmsg->next);
1534 	} else if (ret) {
1535 		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1536 		list_del(&txmsg->next);
1537 		if (txmsg->seqno != -1)
1538 			txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1539 		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
1540 #ifdef __NetBSD__
1541 		DRM_WAKEUP_ONE(&mgr->tx_waitq, &mgr->qlock);
1542 #else
1543 		wake_up(&mgr->tx_waitq);
1544 #endif
1545 	}
1546 	if (list_empty(&mgr->tx_msg_downq)) {
1547 		mgr->tx_down_in_progress = false;
1548 		return;
1549 	}
1550 }
1551 
1552 /* called holding qlock */
1553 static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1554 				       struct drm_dp_sideband_msg_tx *txmsg)
1555 {
1556 	int ret;
1557 
1558 	/* construct a chunk from the first msg in the tx_msg queue */
1559 	ret = process_single_tx_qlock(mgr, txmsg, true);
1560 
1561 	if (ret != 1)
1562 		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1563 
1564 	txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1565 }
1566 
1567 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
1568 				 struct drm_dp_sideband_msg_tx *txmsg)
1569 {
1570 	mutex_lock(&mgr->qlock);
1571 	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
1572 	if (!mgr->tx_down_in_progress)
1573 		process_single_down_tx_qlock(mgr);
1574 	mutex_unlock(&mgr->qlock);
1575 }
1576 
1577 static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1578 				     struct drm_dp_mst_branch *mstb)
1579 {
1580 	int len __unused;
1581 	struct drm_dp_sideband_msg_tx *txmsg;
1582 	int ret;
1583 
1584 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1585 	if (!txmsg)
1586 		return;
1587 
1588 	txmsg->dst = mstb;
1589 	len = build_link_address(txmsg);
1590 
1591 	mstb->link_address_sent = true;
1592 	drm_dp_queue_down_tx(mgr, txmsg);
1593 
1594 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1595 	if (ret > 0) {
1596 		int i;
1597 
1598 		if (txmsg->reply.reply_type == 1)
1599 			DRM_DEBUG_KMS("link address nak received\n");
1600 		else {
1601 			DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
1602 			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1603 				DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n", i,
1604 				       txmsg->reply.u.link_addr.ports[i].input_port,
1605 				       txmsg->reply.u.link_addr.ports[i].peer_device_type,
1606 				       txmsg->reply.u.link_addr.ports[i].port_number,
1607 				       txmsg->reply.u.link_addr.ports[i].dpcd_revision,
1608 				       txmsg->reply.u.link_addr.ports[i].mcs,
1609 				       txmsg->reply.u.link_addr.ports[i].ddps,
1610 				       txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status,
1611 				       txmsg->reply.u.link_addr.ports[i].num_sdp_streams,
1612 				       txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks);
1613 			}
1614 
1615 			drm_dp_check_mstb_guid(mstb, txmsg->reply.u.link_addr.guid);
1616 
1617 			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1618 				drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
1619 			}
1620 			(*mgr->cbs->hotplug)(mgr);
1621 		}
1622 	} else {
1623 		mstb->link_address_sent = false;
1624 		DRM_DEBUG_KMS("link address failed %d\n", ret);
1625 	}
1626 
1627 	kfree(txmsg);
1628 }
1629 
1630 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
1631 					   struct drm_dp_mst_branch *mstb,
1632 					   struct drm_dp_mst_port *port)
1633 {
1634 	int len __unused;
1635 	struct drm_dp_sideband_msg_tx *txmsg;
1636 	int ret;
1637 
1638 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1639 	if (!txmsg)
1640 		return -ENOMEM;
1641 
1642 	txmsg->dst = mstb;
1643 	len = build_enum_path_resources(txmsg, port->port_num);
1644 
1645 	drm_dp_queue_down_tx(mgr, txmsg);
1646 
1647 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1648 	if (ret > 0) {
1649 		if (txmsg->reply.reply_type == 1)
1650 			DRM_DEBUG_KMS("enum path resources nak received\n");
1651 		else {
1652 			if (port->port_num != txmsg->reply.u.path_resources.port_number)
1653 				DRM_ERROR("got incorrect port in response\n");
1654 			DRM_DEBUG_KMS("enum path resources %d: %d %d\n", txmsg->reply.u.path_resources.port_number, txmsg->reply.u.path_resources.full_payload_bw_number,
1655 			       txmsg->reply.u.path_resources.avail_payload_bw_number);
1656 			port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number;
1657 		}
1658 	}
1659 
1660 	kfree(txmsg);
1661 	return 0;
1662 }
1663 
1664 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
1665 {
1666 	if (!mstb->port_parent)
1667 		return NULL;
1668 
1669 	if (mstb->port_parent->mstb != mstb)
1670 		return mstb->port_parent;
1671 
1672 	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
1673 }
1674 
1675 static struct drm_dp_mst_branch *drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
1676 									 struct drm_dp_mst_branch *mstb,
1677 									 int *port_num)
1678 {
1679 	struct drm_dp_mst_branch *rmstb = NULL;
1680 	struct drm_dp_mst_port *found_port;
1681 	mutex_lock(&mgr->lock);
1682 	if (mgr->mst_primary) {
1683 		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
1684 
1685 		if (found_port) {
1686 			rmstb = found_port->parent;
1687 			kref_get(&rmstb->kref);
1688 			*port_num = found_port->port_num;
1689 		}
1690 	}
1691 	mutex_unlock(&mgr->lock);
1692 	return rmstb;
1693 }
1694 
1695 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
1696 				   struct drm_dp_mst_port *port,
1697 				   int id,
1698 				   int pbn)
1699 {
1700 	struct drm_dp_sideband_msg_tx *txmsg;
1701 	struct drm_dp_mst_branch *mstb;
1702 	int len __unused, ret, port_num;
1703 
1704 	port = drm_dp_get_validated_port_ref(mgr, port);
1705 	if (!port)
1706 		return -EINVAL;
1707 
1708 	port_num = port->port_num;
1709 	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1710 	if (!mstb) {
1711 		mstb = drm_dp_get_last_connected_port_and_mstb(mgr, port->parent, &port_num);
1712 
1713 		if (!mstb) {
1714 			drm_dp_put_port(port);
1715 			return -EINVAL;
1716 		}
1717 	}
1718 
1719 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1720 	if (!txmsg) {
1721 		ret = -ENOMEM;
1722 		goto fail_put;
1723 	}
1724 
1725 	txmsg->dst = mstb;
1726 	len = build_allocate_payload(txmsg, port_num,
1727 				     id,
1728 				     pbn);
1729 
1730 	drm_dp_queue_down_tx(mgr, txmsg);
1731 
1732 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1733 	if (ret > 0) {
1734 		if (txmsg->reply.reply_type == 1) {
1735 			ret = -EINVAL;
1736 		} else
1737 			ret = 0;
1738 	}
1739 	kfree(txmsg);
1740 fail_put:
1741 	drm_dp_put_mst_branch_device(mstb);
1742 	drm_dp_put_port(port);
1743 	return ret;
1744 }
1745 
1746 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1747 				       int id,
1748 				       struct drm_dp_payload *payload)
1749 {
1750 	int ret;
1751 
1752 	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
1753 	if (ret < 0) {
1754 		payload->payload_state = 0;
1755 		return ret;
1756 	}
1757 	payload->payload_state = DP_PAYLOAD_LOCAL;
1758 	return 0;
1759 }
1760 
1761 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1762 				       struct drm_dp_mst_port *port,
1763 				       int id,
1764 				       struct drm_dp_payload *payload)
1765 {
1766 	int ret;
1767 	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
1768 	if (ret < 0)
1769 		return ret;
1770 	payload->payload_state = DP_PAYLOAD_REMOTE;
1771 	return ret;
1772 }
1773 
1774 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1775 					struct drm_dp_mst_port *port,
1776 					int id,
1777 					struct drm_dp_payload *payload)
1778 {
1779 	DRM_DEBUG_KMS("\n");
1780 	/* its okay for these to fail */
1781 	if (port) {
1782 		drm_dp_payload_send_msg(mgr, port, id, 0);
1783 	}
1784 
1785 	drm_dp_dpcd_write_payload(mgr, id, payload);
1786 	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
1787 	return 0;
1788 }
1789 
1790 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1791 					int id,
1792 					struct drm_dp_payload *payload)
1793 {
1794 	payload->payload_state = 0;
1795 	return 0;
1796 }
1797 
1798 /**
1799  * drm_dp_update_payload_part1() - Execute payload update part 1
1800  * @mgr: manager to use.
1801  *
1802  * This iterates over all proposed virtual channels, and tries to
1803  * allocate space in the link for them. For 0->slots transitions,
1804  * this step just writes the VCPI to the MST device. For slots->0
1805  * transitions, this writes the updated VCPIs and removes the
1806  * remote VC payloads.
1807  *
1808  * after calling this the driver should generate ACT and payload
1809  * packets.
1810  */
1811 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
1812 {
1813 	int i, j;
1814 	int cur_slots = 1;
1815 	struct drm_dp_payload req_payload;
1816 	struct drm_dp_mst_port *port;
1817 
1818 	mutex_lock(&mgr->payload_lock);
1819 	for (i = 0; i < mgr->max_payloads; i++) {
1820 		/* solve the current payloads - compare to the hw ones
1821 		   - update the hw view */
1822 		req_payload.start_slot = cur_slots;
1823 		if (mgr->proposed_vcpis[i]) {
1824 			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1825 			port = drm_dp_get_validated_port_ref(mgr, port);
1826 			if (!port) {
1827 				mutex_unlock(&mgr->payload_lock);
1828 				return -EINVAL;
1829 			}
1830 			req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
1831 			req_payload.vcpi = mgr->proposed_vcpis[i]->vcpi;
1832 		} else {
1833 			port = NULL;
1834 			req_payload.num_slots = 0;
1835 		}
1836 
1837 		if (mgr->payloads[i].start_slot != req_payload.start_slot) {
1838 			mgr->payloads[i].start_slot = req_payload.start_slot;
1839 		}
1840 		/* work out what is required to happen with this payload */
1841 		if (mgr->payloads[i].num_slots != req_payload.num_slots) {
1842 
1843 			/* need to push an update for this payload */
1844 			if (req_payload.num_slots) {
1845 				drm_dp_create_payload_step1(mgr, mgr->proposed_vcpis[i]->vcpi, &req_payload);
1846 				mgr->payloads[i].num_slots = req_payload.num_slots;
1847 				mgr->payloads[i].vcpi = req_payload.vcpi;
1848 			} else if (mgr->payloads[i].num_slots) {
1849 				mgr->payloads[i].num_slots = 0;
1850 				drm_dp_destroy_payload_step1(mgr, port, mgr->payloads[i].vcpi, &mgr->payloads[i]);
1851 				req_payload.payload_state = mgr->payloads[i].payload_state;
1852 				mgr->payloads[i].start_slot = 0;
1853 			}
1854 			mgr->payloads[i].payload_state = req_payload.payload_state;
1855 		}
1856 		cur_slots += req_payload.num_slots;
1857 
1858 		if (port)
1859 			drm_dp_put_port(port);
1860 	}
1861 
1862 	for (i = 0; i < mgr->max_payloads; i++) {
1863 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1864 			DRM_DEBUG_KMS("removing payload %d\n", i);
1865 			for (j = i; j < mgr->max_payloads - 1; j++) {
1866 				memcpy(&mgr->payloads[j], &mgr->payloads[j + 1], sizeof(struct drm_dp_payload));
1867 				mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
1868 				if (mgr->proposed_vcpis[j] && mgr->proposed_vcpis[j]->num_slots) {
1869 					set_bit(j + 1, &mgr->payload_mask);
1870 				} else {
1871 					clear_bit(j + 1, &mgr->payload_mask);
1872 				}
1873 			}
1874 			memset(&mgr->payloads[mgr->max_payloads - 1], 0, sizeof(struct drm_dp_payload));
1875 			mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
1876 			clear_bit(mgr->max_payloads, &mgr->payload_mask);
1877 
1878 		}
1879 	}
1880 	mutex_unlock(&mgr->payload_lock);
1881 
1882 	return 0;
1883 }
1884 EXPORT_SYMBOL(drm_dp_update_payload_part1);
1885 
1886 /**
1887  * drm_dp_update_payload_part2() - Execute payload update part 2
1888  * @mgr: manager to use.
1889  *
1890  * This iterates over all proposed virtual channels, and tries to
1891  * allocate space in the link for them. For 0->slots transitions,
1892  * this step writes the remote VC payload commands. For slots->0
1893  * this just resets some internal state.
1894  */
1895 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
1896 {
1897 	struct drm_dp_mst_port *port;
1898 	int i;
1899 	int ret = 0;
1900 	mutex_lock(&mgr->payload_lock);
1901 	for (i = 0; i < mgr->max_payloads; i++) {
1902 
1903 		if (!mgr->proposed_vcpis[i])
1904 			continue;
1905 
1906 		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1907 
1908 		DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
1909 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
1910 			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1911 		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1912 			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1913 		}
1914 		if (ret) {
1915 			mutex_unlock(&mgr->payload_lock);
1916 			return ret;
1917 		}
1918 	}
1919 	mutex_unlock(&mgr->payload_lock);
1920 	return 0;
1921 }
1922 EXPORT_SYMBOL(drm_dp_update_payload_part2);
1923 
1924 #if 0 /* unused as of yet */
1925 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
1926 				 struct drm_dp_mst_port *port,
1927 				 int offset, int size)
1928 {
1929 	int len;
1930 	struct drm_dp_sideband_msg_tx *txmsg;
1931 
1932 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1933 	if (!txmsg)
1934 		return -ENOMEM;
1935 
1936 	len = build_dpcd_read(txmsg, port->port_num, 0, 8);
1937 	txmsg->dst = port->parent;
1938 
1939 	drm_dp_queue_down_tx(mgr, txmsg);
1940 
1941 	return 0;
1942 }
1943 #endif
1944 
1945 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
1946 				  struct drm_dp_mst_port *port,
1947 				  int offset, int size, u8 *bytes)
1948 {
1949 	int len __unused;
1950 	int ret;
1951 	struct drm_dp_sideband_msg_tx *txmsg;
1952 	struct drm_dp_mst_branch *mstb;
1953 
1954 	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1955 	if (!mstb)
1956 		return -EINVAL;
1957 
1958 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1959 	if (!txmsg) {
1960 		ret = -ENOMEM;
1961 		goto fail_put;
1962 	}
1963 
1964 	len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
1965 	txmsg->dst = mstb;
1966 
1967 	drm_dp_queue_down_tx(mgr, txmsg);
1968 
1969 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1970 	if (ret > 0) {
1971 		if (txmsg->reply.reply_type == 1) {
1972 			ret = -EINVAL;
1973 		} else
1974 			ret = 0;
1975 	}
1976 	kfree(txmsg);
1977 fail_put:
1978 	drm_dp_put_mst_branch_device(mstb);
1979 	return ret;
1980 }
1981 
1982 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
1983 {
1984 	struct drm_dp_sideband_msg_reply_body reply;
1985 
1986 	reply.reply_type = 1;
1987 	reply.req_type = req_type;
1988 	drm_dp_encode_sideband_reply(&reply, msg);
1989 	return 0;
1990 }
1991 
1992 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
1993 				    struct drm_dp_mst_branch *mstb,
1994 				    int req_type, int seqno, bool broadcast)
1995 {
1996 	struct drm_dp_sideband_msg_tx *txmsg;
1997 
1998 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1999 	if (!txmsg)
2000 		return -ENOMEM;
2001 
2002 	txmsg->dst = mstb;
2003 	txmsg->seqno = seqno;
2004 	drm_dp_encode_up_ack_reply(txmsg, req_type);
2005 
2006 	mutex_lock(&mgr->qlock);
2007 
2008 	process_single_up_tx_qlock(mgr, txmsg);
2009 
2010 	mutex_unlock(&mgr->qlock);
2011 
2012 	kfree(txmsg);
2013 	return 0;
2014 }
2015 
2016 static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
2017 				     int dp_link_count,
2018 				     int *out)
2019 {
2020 	switch (dp_link_bw) {
2021 	default:
2022 		DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
2023 			      dp_link_bw, dp_link_count);
2024 		return false;
2025 
2026 	case DP_LINK_BW_1_62:
2027 		*out = 3 * dp_link_count;
2028 		break;
2029 	case DP_LINK_BW_2_7:
2030 		*out = 5 * dp_link_count;
2031 		break;
2032 	case DP_LINK_BW_5_4:
2033 		*out = 10 * dp_link_count;
2034 		break;
2035 	}
2036 	return true;
2037 }
2038 
2039 /**
2040  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
2041  * @mgr: manager to set state for
2042  * @mst_state: true to enable MST on this connector - false to disable.
2043  *
2044  * This is called by the driver when it detects an MST capable device plugged
2045  * into a DP MST capable port, or when a DP MST capable device is unplugged.
2046  */
2047 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
2048 {
2049 	int ret = 0;
2050 	struct drm_dp_mst_branch *mstb = NULL;
2051 
2052 	mutex_lock(&mgr->lock);
2053 	if (mst_state == mgr->mst_state)
2054 		goto out_unlock;
2055 
2056 	mgr->mst_state = mst_state;
2057 	/* set the device into MST mode */
2058 	if (mst_state) {
2059 		WARN_ON(mgr->mst_primary);
2060 
2061 		/* get dpcd info */
2062 		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2063 		if (ret != DP_RECEIVER_CAP_SIZE) {
2064 			DRM_DEBUG_KMS("failed to read DPCD\n");
2065 			goto out_unlock;
2066 		}
2067 
2068 		if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
2069 					      mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
2070 					      &mgr->pbn_div)) {
2071 			ret = -EINVAL;
2072 			goto out_unlock;
2073 		}
2074 
2075 		mgr->total_pbn = 2560;
2076 		mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
2077 		mgr->avail_slots = mgr->total_slots;
2078 
2079 		/* add initial branch device at LCT 1 */
2080 		mstb = drm_dp_add_mst_branch_device(1, NULL);
2081 		if (mstb == NULL) {
2082 			ret = -ENOMEM;
2083 			goto out_unlock;
2084 		}
2085 		mstb->mgr = mgr;
2086 
2087 		/* give this the main reference */
2088 		mgr->mst_primary = mstb;
2089 		kref_get(&mgr->mst_primary->kref);
2090 
2091 		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2092 							 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2093 		if (ret < 0) {
2094 			goto out_unlock;
2095 		}
2096 
2097 		{
2098 			struct drm_dp_payload reset_pay;
2099 			reset_pay.start_slot = 0;
2100 			reset_pay.num_slots = 0x3f;
2101 			drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
2102 		}
2103 
2104 		queue_work(system_long_wq, &mgr->work);
2105 
2106 		ret = 0;
2107 	} else {
2108 		/* disable MST on the device */
2109 		mstb = mgr->mst_primary;
2110 		mgr->mst_primary = NULL;
2111 		/* this can fail if the device is gone */
2112 		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
2113 		ret = 0;
2114 		memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload));
2115 		mgr->payload_mask = 0;
2116 		set_bit(0, &mgr->payload_mask);
2117 		mgr->vcpi_mask = 0;
2118 	}
2119 
2120 out_unlock:
2121 	mutex_unlock(&mgr->lock);
2122 	if (mstb)
2123 		drm_dp_put_mst_branch_device(mstb);
2124 	return ret;
2125 
2126 }
2127 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
2128 
2129 /**
2130  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
2131  * @mgr: manager to suspend
2132  *
2133  * This function tells the MST device that we can't handle UP messages
2134  * anymore. This should stop it from sending any since we are suspended.
2135  */
2136 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
2137 {
2138 	mutex_lock(&mgr->lock);
2139 	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2140 			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
2141 	mutex_unlock(&mgr->lock);
2142 	flush_work(&mgr->work);
2143 	flush_work(&mgr->destroy_connector_work);
2144 }
2145 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
2146 
2147 /**
2148  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
2149  * @mgr: manager to resume
2150  *
2151  * This will fetch DPCD and see if the device is still there,
2152  * if it is, it will rewrite the MSTM control bits, and return.
2153  *
2154  * if the device fails this returns -1, and the driver should do
2155  * a full MST reprobe, in case we were undocked.
2156  */
2157 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
2158 {
2159 	int ret = 0;
2160 
2161 	mutex_lock(&mgr->lock);
2162 
2163 	if (mgr->mst_primary) {
2164 		int sret;
2165 		u8 guid[16];
2166 
2167 		sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2168 		if (sret != DP_RECEIVER_CAP_SIZE) {
2169 			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2170 			ret = -1;
2171 			goto out_unlock;
2172 		}
2173 
2174 		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2175 					 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2176 		if (ret < 0) {
2177 			DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
2178 			ret = -1;
2179 			goto out_unlock;
2180 		}
2181 
2182 		/* Some hubs forget their guids after they resume */
2183 		sret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
2184 		if (sret != 16) {
2185 			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2186 			ret = -1;
2187 			goto out_unlock;
2188 		}
2189 		drm_dp_check_mstb_guid(mgr->mst_primary, guid);
2190 
2191 		ret = 0;
2192 	} else
2193 		ret = -1;
2194 
2195 out_unlock:
2196 	mutex_unlock(&mgr->lock);
2197 	return ret;
2198 }
2199 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
2200 
2201 static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
2202 {
2203 	int len;
2204 	u8 replyblock[32];
2205 	int replylen, origlen __unused, curreply;
2206 	int ret;
2207 	struct drm_dp_sideband_msg_rx *msg;
2208 	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE;
2209 	msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
2210 
2211 	len = min(mgr->max_dpcd_transaction_bytes, 16);
2212 	ret = drm_dp_dpcd_read(mgr->aux, basereg,
2213 			       replyblock, len);
2214 	if (ret != len) {
2215 		DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
2216 		return false;
2217 	}
2218 	ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
2219 	if (!ret) {
2220 		DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
2221 		return false;
2222 	}
2223 	replylen = msg->curchunk_len + msg->curchunk_hdrlen;
2224 
2225 	origlen = replylen;
2226 	replylen -= len;
2227 	curreply = len;
2228 	while (replylen > 0) {
2229 		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
2230 		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
2231 				    replyblock, len);
2232 		if (ret != len) {
2233 			DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n",
2234 				      len, ret);
2235 			return false;
2236 		}
2237 
2238 		ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
2239 		if (!ret) {
2240 			DRM_DEBUG_KMS("failed to build sideband msg\n");
2241 			return false;
2242 		}
2243 
2244 		curreply += len;
2245 		replylen -= len;
2246 	}
2247 	return true;
2248 }
2249 
2250 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
2251 {
2252 	int ret = 0;
2253 
2254 	if (!drm_dp_get_one_sb_msg(mgr, false)) {
2255 		memset(&mgr->down_rep_recv, 0,
2256 		       sizeof(struct drm_dp_sideband_msg_rx));
2257 		return 0;
2258 	}
2259 
2260 	if (mgr->down_rep_recv.have_eomt) {
2261 		struct drm_dp_sideband_msg_tx *txmsg;
2262 		struct drm_dp_mst_branch *mstb;
2263 		int slot = -1;
2264 		mstb = drm_dp_get_mst_branch_device(mgr,
2265 						    mgr->down_rep_recv.initial_hdr.lct,
2266 						    mgr->down_rep_recv.initial_hdr.rad);
2267 
2268 		if (!mstb) {
2269 			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->down_rep_recv.initial_hdr.lct);
2270 			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2271 			return 0;
2272 		}
2273 
2274 		/* find the message */
2275 		slot = mgr->down_rep_recv.initial_hdr.seqno;
2276 		mutex_lock(&mgr->qlock);
2277 		txmsg = mstb->tx_slots[slot];
2278 		/* remove from slots */
2279 		mutex_unlock(&mgr->qlock);
2280 
2281 		if (!txmsg) {
2282 			DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
2283 			       mstb,
2284 			       mgr->down_rep_recv.initial_hdr.seqno,
2285 			       mgr->down_rep_recv.initial_hdr.lct,
2286 				      mgr->down_rep_recv.initial_hdr.rad[0],
2287 				      mgr->down_rep_recv.msg[0]);
2288 			drm_dp_put_mst_branch_device(mstb);
2289 			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2290 			return 0;
2291 		}
2292 
2293 		drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
2294 		if (txmsg->reply.reply_type == 1) {
2295 			DRM_DEBUG_KMS("Got NAK reply: req 0x%02x, reason 0x%02x, nak data 0x%02x\n", txmsg->reply.req_type, txmsg->reply.u.nak.reason, txmsg->reply.u.nak.nak_data);
2296 		}
2297 
2298 		memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2299 		drm_dp_put_mst_branch_device(mstb);
2300 
2301 		mutex_lock(&mgr->qlock);
2302 		txmsg->state = DRM_DP_SIDEBAND_TX_RX;
2303 		mstb->tx_slots[slot] = NULL;
2304 #ifdef __NetBSD__
2305 		DRM_WAKEUP_ONE(&mstb->mgr->tx_waitq, &mstb->mgr->qlock);
2306 		mutex_unlock(&mgr->qlock);
2307 #else
2308 		mutex_unlock(&mgr->qlock);
2309 
2310 		wake_up(&mgr->tx_waitq);
2311 #endif
2312 	}
2313 	return ret;
2314 }
2315 
2316 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
2317 {
2318 	int ret = 0;
2319 
2320 	if (!drm_dp_get_one_sb_msg(mgr, true)) {
2321 		memset(&mgr->up_req_recv, 0,
2322 		       sizeof(struct drm_dp_sideband_msg_rx));
2323 		return 0;
2324 	}
2325 
2326 	if (mgr->up_req_recv.have_eomt) {
2327 		struct drm_dp_sideband_msg_req_body msg;
2328 		struct drm_dp_mst_branch *mstb = NULL;
2329 		bool seqno;
2330 
2331 		if (!mgr->up_req_recv.initial_hdr.broadcast) {
2332 			mstb = drm_dp_get_mst_branch_device(mgr,
2333 							    mgr->up_req_recv.initial_hdr.lct,
2334 							    mgr->up_req_recv.initial_hdr.rad);
2335 			if (!mstb) {
2336 				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2337 				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2338 				return 0;
2339 			}
2340 		}
2341 
2342 		seqno = mgr->up_req_recv.initial_hdr.seqno;
2343 		drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
2344 
2345 		if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
2346 			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2347 
2348 			if (!mstb)
2349 				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
2350 
2351 			if (!mstb) {
2352 				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2353 				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2354 				return 0;
2355 			}
2356 
2357 			drm_dp_update_port(mstb, &msg.u.conn_stat);
2358 
2359 			DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type);
2360 			(*mgr->cbs->hotplug)(mgr);
2361 
2362 		} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
2363 			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2364 			if (!mstb)
2365 				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
2366 
2367 			if (!mstb) {
2368 				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2369 				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2370 				return 0;
2371 			}
2372 
2373 			DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
2374 		}
2375 
2376 		if (mstb)
2377 			drm_dp_put_mst_branch_device(mstb);
2378 
2379 		memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2380 	}
2381 	return ret;
2382 }
2383 
2384 /**
2385  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
2386  * @mgr: manager to notify irq for.
2387  * @esi: 4 bytes from SINK_COUNT_ESI
2388  * @handled: whether the hpd interrupt was consumed or not
2389  *
2390  * This should be called from the driver when it detects a short IRQ,
2391  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
2392  * topology manager will process the sideband messages received as a result
2393  * of this.
2394  */
2395 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
2396 {
2397 	int ret = 0;
2398 	int sc;
2399 	*handled = false;
2400 	sc = esi[0] & 0x3f;
2401 
2402 	if (sc != mgr->sink_count) {
2403 		mgr->sink_count = sc;
2404 		*handled = true;
2405 	}
2406 
2407 	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
2408 		ret = drm_dp_mst_handle_down_rep(mgr);
2409 		*handled = true;
2410 	}
2411 
2412 	if (esi[1] & DP_UP_REQ_MSG_RDY) {
2413 		ret |= drm_dp_mst_handle_up_req(mgr);
2414 		*handled = true;
2415 	}
2416 
2417 	drm_dp_mst_kick_tx(mgr);
2418 	return ret;
2419 }
2420 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
2421 
2422 /**
2423  * drm_dp_mst_detect_port() - get connection status for an MST port
2424  * @mgr: manager for this port
2425  * @port: unverified pointer to a port
2426  *
2427  * This returns the current connection state for a port. It validates the
2428  * port pointer still exists so the caller doesn't require a reference
2429  */
2430 enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector,
2431 						 struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2432 {
2433 	enum drm_connector_status status = connector_status_disconnected;
2434 
2435 	/* we need to search for the port in the mgr in case its gone */
2436 	port = drm_dp_get_validated_port_ref(mgr, port);
2437 	if (!port)
2438 		return connector_status_disconnected;
2439 
2440 	if (!port->ddps)
2441 		goto out;
2442 
2443 	switch (port->pdt) {
2444 	case DP_PEER_DEVICE_NONE:
2445 	case DP_PEER_DEVICE_MST_BRANCHING:
2446 		break;
2447 
2448 	case DP_PEER_DEVICE_SST_SINK:
2449 		status = connector_status_connected;
2450 		/* for logical ports - cache the EDID */
2451 		if (port->port_num >= 8 && !port->cached_edid) {
2452 			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
2453 		}
2454 		break;
2455 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2456 		if (port->ldps)
2457 			status = connector_status_connected;
2458 		break;
2459 	}
2460 out:
2461 	drm_dp_put_port(port);
2462 	return status;
2463 }
2464 EXPORT_SYMBOL(drm_dp_mst_detect_port);
2465 
2466 /**
2467  * drm_dp_mst_get_edid() - get EDID for an MST port
2468  * @connector: toplevel connector to get EDID for
2469  * @mgr: manager for this port
2470  * @port: unverified pointer to a port.
2471  *
2472  * This returns an EDID for the port connected to a connector,
2473  * It validates the pointer still exists so the caller doesn't require a
2474  * reference.
2475  */
2476 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2477 {
2478 	struct edid *edid = NULL;
2479 
2480 	/* we need to search for the port in the mgr in case its gone */
2481 	port = drm_dp_get_validated_port_ref(mgr, port);
2482 	if (!port)
2483 		return NULL;
2484 
2485 	if (port->cached_edid)
2486 		edid = drm_edid_duplicate(port->cached_edid);
2487 	else {
2488 		edid = drm_get_edid(connector, &port->aux.ddc);
2489 		drm_mode_connector_set_tile_property(connector);
2490 	}
2491 	drm_dp_put_port(port);
2492 	return edid;
2493 }
2494 EXPORT_SYMBOL(drm_dp_mst_get_edid);
2495 
2496 /**
2497  * drm_dp_find_vcpi_slots() - find slots for this PBN value
2498  * @mgr: manager to use
2499  * @pbn: payload bandwidth to convert into slots.
2500  */
2501 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
2502 			   int pbn)
2503 {
2504 	int num_slots;
2505 
2506 	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2507 
2508 	if (num_slots > mgr->avail_slots)
2509 		return -ENOSPC;
2510 	return num_slots;
2511 }
2512 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
2513 
2514 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
2515 			    struct drm_dp_vcpi *vcpi, int pbn)
2516 {
2517 	int num_slots;
2518 	int ret;
2519 
2520 	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2521 
2522 	if (num_slots > mgr->avail_slots)
2523 		return -ENOSPC;
2524 
2525 	vcpi->pbn = pbn;
2526 	vcpi->aligned_pbn = num_slots * mgr->pbn_div;
2527 	vcpi->num_slots = num_slots;
2528 
2529 	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
2530 	if (ret < 0)
2531 		return ret;
2532 	return 0;
2533 }
2534 
2535 /**
2536  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
2537  * @mgr: manager for this port
2538  * @port: port to allocate a virtual channel for.
2539  * @pbn: payload bandwidth number to request
2540  * @slots: returned number of slots for this PBN.
2541  */
2542 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int *slots)
2543 {
2544 	int ret;
2545 
2546 	port = drm_dp_get_validated_port_ref(mgr, port);
2547 	if (!port)
2548 		return false;
2549 
2550 	if (port->vcpi.vcpi > 0) {
2551 		DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn);
2552 		if (pbn == port->vcpi.pbn) {
2553 			*slots = port->vcpi.num_slots;
2554 			drm_dp_put_port(port);
2555 			return true;
2556 		}
2557 	}
2558 
2559 	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn);
2560 	if (ret) {
2561 		DRM_DEBUG_KMS("failed to init vcpi %d %d %d\n", DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->avail_slots, ret);
2562 		goto out;
2563 	}
2564 	DRM_DEBUG_KMS("initing vcpi for %d %d\n", pbn, port->vcpi.num_slots);
2565 	*slots = port->vcpi.num_slots;
2566 
2567 	drm_dp_put_port(port);
2568 	return true;
2569 out:
2570 	return false;
2571 }
2572 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
2573 
2574 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2575 {
2576 	int slots = 0;
2577 	port = drm_dp_get_validated_port_ref(mgr, port);
2578 	if (!port)
2579 		return slots;
2580 
2581 	slots = port->vcpi.num_slots;
2582 	drm_dp_put_port(port);
2583 	return slots;
2584 }
2585 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
2586 
2587 /**
2588  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
2589  * @mgr: manager for this port
2590  * @port: unverified pointer to a port.
2591  *
2592  * This just resets the number of slots for the ports VCPI for later programming.
2593  */
2594 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2595 {
2596 	port = drm_dp_get_validated_port_ref(mgr, port);
2597 	if (!port)
2598 		return;
2599 	port->vcpi.num_slots = 0;
2600 	drm_dp_put_port(port);
2601 }
2602 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
2603 
2604 /**
2605  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
2606  * @mgr: manager for this port
2607  * @port: unverified port to deallocate vcpi for
2608  */
2609 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2610 {
2611 	port = drm_dp_get_validated_port_ref(mgr, port);
2612 	if (!port)
2613 		return;
2614 
2615 	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2616 	port->vcpi.num_slots = 0;
2617 	port->vcpi.pbn = 0;
2618 	port->vcpi.aligned_pbn = 0;
2619 	port->vcpi.vcpi = 0;
2620 	drm_dp_put_port(port);
2621 }
2622 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
2623 
2624 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
2625 				     int id, struct drm_dp_payload *payload)
2626 {
2627 	u8 payload_alloc[3], status;
2628 	int ret;
2629 	int retries = 0;
2630 
2631 	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
2632 			   DP_PAYLOAD_TABLE_UPDATED);
2633 
2634 	payload_alloc[0] = id;
2635 	payload_alloc[1] = payload->start_slot;
2636 	payload_alloc[2] = payload->num_slots;
2637 
2638 	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
2639 	if (ret != 3) {
2640 		DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
2641 		goto fail;
2642 	}
2643 
2644 retry:
2645 	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2646 	if (ret < 0) {
2647 		DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2648 		goto fail;
2649 	}
2650 
2651 	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
2652 		retries++;
2653 		if (retries < 20) {
2654 			usleep_range(10000, 20000);
2655 			goto retry;
2656 		}
2657 		DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
2658 		ret = -EINVAL;
2659 		goto fail;
2660 	}
2661 	ret = 0;
2662 fail:
2663 	return ret;
2664 }
2665 
2666 
2667 /**
2668  * drm_dp_check_act_status() - Check ACT handled status.
2669  * @mgr: manager to use
2670  *
2671  * Check the payload status bits in the DPCD for ACT handled completion.
2672  */
2673 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
2674 {
2675 	u8 status;
2676 	int ret;
2677 	int count = 0;
2678 
2679 	do {
2680 		ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2681 
2682 		if (ret < 0) {
2683 			DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2684 			goto fail;
2685 		}
2686 
2687 		if (status & DP_PAYLOAD_ACT_HANDLED)
2688 			break;
2689 		count++;
2690 		udelay(100);
2691 
2692 	} while (count < 30);
2693 
2694 	if (!(status & DP_PAYLOAD_ACT_HANDLED)) {
2695 		DRM_DEBUG_KMS("failed to get ACT bit %d after %d retries\n", status, count);
2696 		ret = -EINVAL;
2697 		goto fail;
2698 	}
2699 	return 0;
2700 fail:
2701 	return ret;
2702 }
2703 EXPORT_SYMBOL(drm_dp_check_act_status);
2704 
2705 /**
2706  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
2707  * @clock: dot clock for the mode
2708  * @bpp: bpp for the mode.
2709  *
2710  * This uses the formula in the spec to calculate the PBN value for a mode.
2711  */
2712 int drm_dp_calc_pbn_mode(int clock, int bpp)
2713 {
2714 	u64 kbps;
2715 	s64 peak_kbps;
2716 	u32 numerator;
2717 	u32 denominator;
2718 
2719 	kbps = clock * bpp;
2720 
2721 	/*
2722 	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
2723 	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
2724 	 * common multiplier to render an integer PBN for all link rate/lane
2725 	 * counts combinations
2726 	 * calculate
2727 	 * peak_kbps *= (1006/1000)
2728 	 * peak_kbps *= (64/54)
2729 	 * peak_kbps *= 8    convert to bytes
2730 	 */
2731 
2732 	numerator = 64 * 1006;
2733 	denominator = 54 * 8 * 1000 * 1000;
2734 
2735 	kbps *= numerator;
2736 	peak_kbps = drm_fixp_from_fraction(kbps, denominator);
2737 
2738 	return drm_fixp2int_ceil(peak_kbps);
2739 }
2740 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
2741 
2742 static int test_calc_pbn_mode(void)
2743 {
2744 	int ret;
2745 	ret = drm_dp_calc_pbn_mode(154000, 30);
2746 	if (ret != 689) {
2747 		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2748 				154000, 30, 689, ret);
2749 		return -EINVAL;
2750 	}
2751 	ret = drm_dp_calc_pbn_mode(234000, 30);
2752 	if (ret != 1047) {
2753 		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2754 				234000, 30, 1047, ret);
2755 		return -EINVAL;
2756 	}
2757 	ret = drm_dp_calc_pbn_mode(297000, 24);
2758 	if (ret != 1063) {
2759 		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2760 				297000, 24, 1063, ret);
2761 		return -EINVAL;
2762 	}
2763 	return 0;
2764 }
2765 
2766 /* we want to kick the TX after we've ack the up/down IRQs. */
2767 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
2768 {
2769 	queue_work(system_long_wq, &mgr->tx_work);
2770 }
2771 
2772 #if IS_ENABLED(CONFIG_DEBUG_FS)
2773 static void drm_dp_mst_dump_mstb(struct seq_file *m,
2774 				 struct drm_dp_mst_branch *mstb)
2775 {
2776 	struct drm_dp_mst_port *port;
2777 	int tabs = mstb->lct;
2778 	char prefix[10];
2779 	int i;
2780 
2781 	for (i = 0; i < tabs; i++)
2782 		prefix[i] = '\t';
2783 	prefix[i] = '\0';
2784 
2785 	seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
2786 	list_for_each_entry(port, &mstb->ports, next) {
2787 		seq_printf(m, "%sport: %d: ddps: %d ldps: %d, %p, conn: %p\n", prefix, port->port_num, port->ddps, port->ldps, port, port->connector);
2788 		if (port->mstb)
2789 			drm_dp_mst_dump_mstb(m, port->mstb);
2790 	}
2791 }
2792 
2793 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
2794 				  char *buf)
2795 {
2796 	int ret;
2797 	int i;
2798 	for (i = 0; i < 4; i++) {
2799 		ret = drm_dp_dpcd_read(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS + (i * 16), &buf[i * 16], 16);
2800 		if (ret != 16)
2801 			break;
2802 	}
2803 	if (i == 4)
2804 		return true;
2805 	return false;
2806 }
2807 
2808 /**
2809  * drm_dp_mst_dump_topology(): dump topology to seq file.
2810  * @m: seq_file to dump output to
2811  * @mgr: manager to dump current topology for.
2812  *
2813  * helper to dump MST topology to a seq file for debugfs.
2814  */
2815 void drm_dp_mst_dump_topology(struct seq_file *m,
2816 			      struct drm_dp_mst_topology_mgr *mgr)
2817 {
2818 	int i;
2819 	struct drm_dp_mst_port *port;
2820 	mutex_lock(&mgr->lock);
2821 	if (mgr->mst_primary)
2822 		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
2823 
2824 	/* dump VCPIs */
2825 	mutex_unlock(&mgr->lock);
2826 
2827 	mutex_lock(&mgr->payload_lock);
2828 	seq_printf(m, "vcpi: %lx %lx\n", mgr->payload_mask, mgr->vcpi_mask);
2829 
2830 	for (i = 0; i < mgr->max_payloads; i++) {
2831 		if (mgr->proposed_vcpis[i]) {
2832 			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
2833 			seq_printf(m, "vcpi %d: %d %d %d\n", i, port->port_num, port->vcpi.vcpi, port->vcpi.num_slots);
2834 		} else
2835 			seq_printf(m, "vcpi %d:unsed\n", i);
2836 	}
2837 	for (i = 0; i < mgr->max_payloads; i++) {
2838 		seq_printf(m, "payload %d: %d, %d, %d\n",
2839 			   i,
2840 			   mgr->payloads[i].payload_state,
2841 			   mgr->payloads[i].start_slot,
2842 			   mgr->payloads[i].num_slots);
2843 
2844 
2845 	}
2846 	mutex_unlock(&mgr->payload_lock);
2847 
2848 	mutex_lock(&mgr->lock);
2849 	if (mgr->mst_primary) {
2850 		u8 buf[64];
2851 		bool bret;
2852 		int ret;
2853 		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
2854 		seq_printf(m, "dpcd: ");
2855 		for (i = 0; i < DP_RECEIVER_CAP_SIZE; i++)
2856 			seq_printf(m, "%02x ", buf[i]);
2857 		seq_printf(m, "\n");
2858 		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
2859 		seq_printf(m, "faux/mst: ");
2860 		for (i = 0; i < 2; i++)
2861 			seq_printf(m, "%02x ", buf[i]);
2862 		seq_printf(m, "\n");
2863 		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
2864 		seq_printf(m, "mst ctrl: ");
2865 		for (i = 0; i < 1; i++)
2866 			seq_printf(m, "%02x ", buf[i]);
2867 		seq_printf(m, "\n");
2868 
2869 		/* dump the standard OUI branch header */
2870 		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
2871 		seq_printf(m, "branch oui: ");
2872 		for (i = 0; i < 0x3; i++)
2873 			seq_printf(m, "%02x", buf[i]);
2874 		seq_printf(m, " devid: ");
2875 		for (i = 0x3; i < 0x8; i++)
2876 			seq_printf(m, "%c", buf[i]);
2877 		seq_printf(m, " revision: hw: %x.%x sw: %x.%x", buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
2878 		seq_printf(m, "\n");
2879 		bret = dump_dp_payload_table(mgr, buf);
2880 		if (bret == true) {
2881 			seq_printf(m, "payload table: ");
2882 			for (i = 0; i < 63; i++)
2883 				seq_printf(m, "%02x ", buf[i]);
2884 			seq_printf(m, "\n");
2885 		}
2886 
2887 	}
2888 
2889 	mutex_unlock(&mgr->lock);
2890 
2891 }
2892 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
2893 #endif	/* IS_ENABLED(CONFIG_DEBUG_FS) */
2894 
2895 static void drm_dp_tx_work(struct work_struct *work)
2896 {
2897 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
2898 
2899 	mutex_lock(&mgr->qlock);
2900 	if (mgr->tx_down_in_progress)
2901 		process_single_down_tx_qlock(mgr);
2902 	mutex_unlock(&mgr->qlock);
2903 }
2904 
2905 static void drm_dp_free_mst_port(struct kref *kref)
2906 {
2907 	struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
2908 	kref_put(&port->parent->kref, drm_dp_free_mst_branch_device);
2909 	kfree(port);
2910 }
2911 
2912 static void drm_dp_destroy_connector_work(struct work_struct *work)
2913 {
2914 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
2915 	struct drm_dp_mst_port *port;
2916 	bool send_hotplug = false;
2917 	/*
2918 	 * Not a regular list traverse as we have to drop the destroy
2919 	 * connector lock before destroying the connector, to avoid AB->BA
2920 	 * ordering between this lock and the config mutex.
2921 	 */
2922 	for (;;) {
2923 		mutex_lock(&mgr->destroy_connector_lock);
2924 		port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next);
2925 		if (!port) {
2926 			mutex_unlock(&mgr->destroy_connector_lock);
2927 			break;
2928 		}
2929 		list_del(&port->next);
2930 		mutex_unlock(&mgr->destroy_connector_lock);
2931 
2932 		kref_init(&port->kref);
2933 		INIT_LIST_HEAD(&port->next);
2934 
2935 		mgr->cbs->destroy_connector(mgr, port->connector);
2936 
2937 		drm_dp_port_teardown_pdt(port, port->pdt);
2938 		port->pdt = DP_PEER_DEVICE_NONE;
2939 
2940 		if (!port->input && port->vcpi.vcpi > 0) {
2941 			drm_dp_mst_reset_vcpi_slots(mgr, port);
2942 			drm_dp_update_payload_part1(mgr);
2943 			drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2944 		}
2945 
2946 		kref_put(&port->kref, drm_dp_free_mst_port);
2947 		send_hotplug = true;
2948 	}
2949 	if (send_hotplug)
2950 		(*mgr->cbs->hotplug)(mgr);
2951 }
2952 
2953 /**
2954  * drm_dp_mst_topology_mgr_init - initialise a topology manager
2955  * @mgr: manager struct to initialise
2956  * @dev: device providing this structure - for i2c addition.
2957  * @aux: DP helper aux channel to talk to this device
2958  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
2959  * @max_payloads: maximum number of payloads this GPU can source
2960  * @conn_base_id: the connector object ID the MST device is connected to.
2961  *
2962  * Return 0 for success, or negative error code on failure
2963  */
2964 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
2965 				 struct device *dev, struct drm_dp_aux *aux,
2966 				 int max_dpcd_transaction_bytes,
2967 				 int max_payloads, int conn_base_id)
2968 {
2969 #ifdef __NetBSD__
2970 	linux_mutex_init(&mgr->lock);
2971 	linux_mutex_init(&mgr->qlock);
2972 	linux_mutex_init(&mgr->payload_lock);
2973 	linux_mutex_init(&mgr->destroy_connector_lock);
2974 #else
2975 	mutex_init(&mgr->lock);
2976 	mutex_init(&mgr->qlock);
2977 	mutex_init(&mgr->payload_lock);
2978 	mutex_init(&mgr->destroy_connector_lock);
2979 #endif
2980 	INIT_LIST_HEAD(&mgr->tx_msg_downq);
2981 	INIT_LIST_HEAD(&mgr->destroy_connector_list);
2982 	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
2983 	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
2984 	INIT_WORK(&mgr->destroy_connector_work, drm_dp_destroy_connector_work);
2985 #ifdef __NetBSD__
2986 	DRM_INIT_WAITQUEUE(&mgr->tx_waitq, "dpmstwait");
2987 #else
2988 	init_waitqueue_head(&mgr->tx_waitq);
2989 #endif
2990 	mgr->dev = dev;
2991 	mgr->aux = aux;
2992 	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
2993 	mgr->max_payloads = max_payloads;
2994 	mgr->conn_base_id = conn_base_id;
2995 	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
2996 	if (!mgr->payloads)
2997 		return -ENOMEM;
2998 	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
2999 	if (!mgr->proposed_vcpis)
3000 		return -ENOMEM;
3001 	set_bit(0, &mgr->payload_mask);
3002 	test_calc_pbn_mode();
3003 	return 0;
3004 }
3005 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
3006 
3007 /**
3008  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
3009  * @mgr: manager to destroy
3010  */
3011 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
3012 {
3013 	flush_work(&mgr->work);
3014 	flush_work(&mgr->destroy_connector_work);
3015 	mutex_lock(&mgr->payload_lock);
3016 	kfree(mgr->payloads);
3017 	mgr->payloads = NULL;
3018 	kfree(mgr->proposed_vcpis);
3019 	mgr->proposed_vcpis = NULL;
3020 	mutex_unlock(&mgr->payload_lock);
3021 	mgr->dev = NULL;
3022 	mgr->aux = NULL;
3023 #ifdef __NetBSD__
3024 	DRM_DESTROY_WAITQUEUE(&mgr->tx_waitq);
3025 	linux_mutex_destroy(&mgr->destroy_connector_lock);
3026 	linux_mutex_destroy(&mgr->payload_lock);
3027 	linux_mutex_destroy(&mgr->qlock);
3028 	linux_mutex_destroy(&mgr->lock);
3029 #else
3030 	mutex_destroy(&mgr->destroy_connector_lock);
3031 	mutex_destroy(&mgr->payload_lock);
3032 	mutex_destroy(&mgr->qlock);
3033 	mutex_destroy(&mgr->lock);
3034 #endif
3035 }
3036 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
3037 
3038 /* I2C device */
3039 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
3040 			       int num)
3041 {
3042 	struct drm_dp_aux *aux = adapter->algo_data;
3043 	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
3044 	struct drm_dp_mst_branch *mstb;
3045 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
3046 	unsigned int i;
3047 	bool reading = false;
3048 	struct drm_dp_sideband_msg_req_body msg;
3049 	struct drm_dp_sideband_msg_tx *txmsg = NULL;
3050 	int ret;
3051 
3052 	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
3053 	if (!mstb)
3054 		return -EREMOTEIO;
3055 
3056 	/* construct i2c msg */
3057 	/* see if last msg is a read */
3058 	if (msgs[num - 1].flags & I2C_M_RD)
3059 		reading = true;
3060 
3061 	if (!reading || (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)) {
3062 		DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
3063 		ret = -EIO;
3064 		goto out;
3065 	}
3066 
3067 	memset(&msg, 0, sizeof(msg));
3068 	msg.req_type = DP_REMOTE_I2C_READ;
3069 	msg.u.i2c_read.num_transactions = num - 1;
3070 	msg.u.i2c_read.port_number = port->port_num;
3071 	for (i = 0; i < num - 1; i++) {
3072 		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
3073 		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
3074 		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
3075 	}
3076 	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
3077 	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
3078 
3079 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3080 	if (!txmsg) {
3081 		ret = -ENOMEM;
3082 		goto out;
3083 	}
3084 
3085 	txmsg->dst = mstb;
3086 	drm_dp_encode_sideband_req(&msg, txmsg);
3087 
3088 	drm_dp_queue_down_tx(mgr, txmsg);
3089 
3090 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3091 	if (ret > 0) {
3092 
3093 		if (txmsg->reply.reply_type == 1) { /* got a NAK back */
3094 			ret = -EREMOTEIO;
3095 			goto out;
3096 		}
3097 		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
3098 			ret = -EIO;
3099 			goto out;
3100 		}
3101 		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
3102 		ret = num;
3103 	}
3104 out:
3105 	kfree(txmsg);
3106 	drm_dp_put_mst_branch_device(mstb);
3107 	return ret;
3108 }
3109 
3110 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
3111 {
3112 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
3113 	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
3114 	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
3115 	       I2C_FUNC_10BIT_ADDR;
3116 }
3117 
3118 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
3119 	.functionality = drm_dp_mst_i2c_functionality,
3120 	.master_xfer = drm_dp_mst_i2c_xfer,
3121 };
3122 
3123 /**
3124  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
3125  * @aux: DisplayPort AUX channel
3126  *
3127  * Returns 0 on success or a negative error code on failure.
3128  */
3129 static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
3130 {
3131 	aux->ddc.algo = &drm_dp_mst_i2c_algo;
3132 	aux->ddc.algo_data = aux;
3133 	aux->ddc.retries = 3;
3134 
3135 	aux->ddc.class = I2C_CLASS_DDC;
3136 	aux->ddc.owner = THIS_MODULE;
3137 	aux->ddc.dev.parent = aux->dev;
3138 #ifndef __NetBSD__		/* XXX of? */
3139 	aux->ddc.dev.of_node = aux->dev->of_node;
3140 #endif
3141 
3142 	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
3143 		sizeof(aux->ddc.name));
3144 
3145 	return i2c_add_adapter(&aux->ddc);
3146 }
3147 
3148 /**
3149  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
3150  * @aux: DisplayPort AUX channel
3151  */
3152 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
3153 {
3154 	i2c_del_adapter(&aux->ddc);
3155 }
3156