xref: /netbsd-src/sys/external/bsd/drm2/dist/drm/drm_dp_mst_topology.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /*	$NetBSD: drm_dp_mst_topology.c,v 1.5 2020/02/14 14:34:57 maya 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 1.5 2020/02/14 14:34:57 maya 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 <drm/drm_dp_mst_helper.h>
36 #include <drm/drmP.h>
37 
38 #include <drm/drm_fixed.h>
39 
40 #include <linux/nbsd-namespace.h>
41 
42 /**
43  * DOC: dp mst helper
44  *
45  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
46  * protocol. The helpers contain a topology manager and bandwidth manager.
47  * The helpers encapsulate the sending and received of sideband msgs.
48  */
49 #if IS_ENABLED(CONFIG_DEBUG_FS)
50 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
51 				  char *buf);
52 #endif
53 static int test_calc_pbn_mode(void);
54 
55 static void drm_dp_put_port(struct drm_dp_mst_port *port);
56 
57 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
58 				     int id,
59 				     struct drm_dp_payload *payload);
60 
61 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
62 				  struct drm_dp_mst_port *port,
63 				  int offset, int size, u8 *bytes);
64 
65 static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
66 				     struct drm_dp_mst_branch *mstb);
67 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
68 					   struct drm_dp_mst_branch *mstb,
69 					   struct drm_dp_mst_port *port);
70 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
71 				 u8 *guid);
72 
73 static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
74 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
75 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
76 /* sideband msg handling */
77 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
78 {
79 	u8 bitmask = 0x80;
80 	u8 bitshift = 7;
81 	u8 array_index = 0;
82 	int number_of_bits = num_nibbles * 4;
83 	u8 remainder = 0;
84 
85 	while (number_of_bits != 0) {
86 		number_of_bits--;
87 		remainder <<= 1;
88 		remainder |= (data[array_index] & bitmask) >> bitshift;
89 		bitmask >>= 1;
90 		bitshift--;
91 		if (bitmask == 0) {
92 			bitmask = 0x80;
93 			bitshift = 7;
94 			array_index++;
95 		}
96 		if ((remainder & 0x10) == 0x10)
97 			remainder ^= 0x13;
98 	}
99 
100 	number_of_bits = 4;
101 	while (number_of_bits != 0) {
102 		number_of_bits--;
103 		remainder <<= 1;
104 		if ((remainder & 0x10) != 0)
105 			remainder ^= 0x13;
106 	}
107 
108 	return remainder;
109 }
110 
111 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
112 {
113 	u8 bitmask = 0x80;
114 	u8 bitshift = 7;
115 	u8 array_index = 0;
116 	int number_of_bits = number_of_bytes * 8;
117 	u16 remainder = 0;
118 
119 	while (number_of_bits != 0) {
120 		number_of_bits--;
121 		remainder <<= 1;
122 		remainder |= (data[array_index] & bitmask) >> bitshift;
123 		bitmask >>= 1;
124 		bitshift--;
125 		if (bitmask == 0) {
126 			bitmask = 0x80;
127 			bitshift = 7;
128 			array_index++;
129 		}
130 		if ((remainder & 0x100) == 0x100)
131 			remainder ^= 0xd5;
132 	}
133 
134 	number_of_bits = 8;
135 	while (number_of_bits != 0) {
136 		number_of_bits--;
137 		remainder <<= 1;
138 		if ((remainder & 0x100) != 0)
139 			remainder ^= 0xd5;
140 	}
141 
142 	return remainder & 0xff;
143 }
144 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
145 {
146 	u8 size = 3;
147 	size += (hdr->lct / 2);
148 	return size;
149 }
150 
151 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
152 					   u8 *buf, int *len)
153 {
154 	int idx = 0;
155 	int i;
156 	u8 crc4;
157 	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
158 	for (i = 0; i < (hdr->lct / 2); i++)
159 		buf[idx++] = hdr->rad[i];
160 	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
161 		(hdr->msg_len & 0x3f);
162 	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
163 
164 	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
165 	buf[idx - 1] |= (crc4 & 0xf);
166 
167 	*len = idx;
168 }
169 
170 static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
171 					   u8 *buf, int buflen, u8 *hdrlen)
172 {
173 	u8 crc4;
174 	u8 len;
175 	int i;
176 	u8 idx;
177 	if (buf[0] == 0)
178 		return false;
179 	len = 3;
180 	len += ((buf[0] & 0xf0) >> 4) / 2;
181 	if (len > buflen)
182 		return false;
183 	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
184 
185 	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
186 		DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
187 		return false;
188 	}
189 
190 	hdr->lct = (buf[0] & 0xf0) >> 4;
191 	hdr->lcr = (buf[0] & 0xf);
192 	idx = 1;
193 	for (i = 0; i < (hdr->lct / 2); i++)
194 		hdr->rad[i] = buf[idx++];
195 	hdr->broadcast = (buf[idx] >> 7) & 0x1;
196 	hdr->path_msg = (buf[idx] >> 6) & 0x1;
197 	hdr->msg_len = buf[idx] & 0x3f;
198 	idx++;
199 	hdr->somt = (buf[idx] >> 7) & 0x1;
200 	hdr->eomt = (buf[idx] >> 6) & 0x1;
201 	hdr->seqno = (buf[idx] >> 4) & 0x1;
202 	idx++;
203 	*hdrlen = idx;
204 	return true;
205 }
206 
207 static void drm_dp_encode_sideband_req(struct drm_dp_sideband_msg_req_body *req,
208 				       struct drm_dp_sideband_msg_tx *raw)
209 {
210 	int idx = 0;
211 	int i;
212 	u8 *buf = raw->msg;
213 	buf[idx++] = req->req_type & 0x7f;
214 
215 	switch (req->req_type) {
216 	case DP_ENUM_PATH_RESOURCES:
217 		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
218 		idx++;
219 		break;
220 	case DP_ALLOCATE_PAYLOAD:
221 		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
222 			(req->u.allocate_payload.number_sdp_streams & 0xf);
223 		idx++;
224 		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
225 		idx++;
226 		buf[idx] = (req->u.allocate_payload.pbn >> 8);
227 		idx++;
228 		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
229 		idx++;
230 		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
231 			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
232 				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
233 			idx++;
234 		}
235 		if (req->u.allocate_payload.number_sdp_streams & 1) {
236 			i = req->u.allocate_payload.number_sdp_streams - 1;
237 			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
238 			idx++;
239 		}
240 		break;
241 	case DP_QUERY_PAYLOAD:
242 		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
243 		idx++;
244 		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
245 		idx++;
246 		break;
247 	case DP_REMOTE_DPCD_READ:
248 		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
249 		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
250 		idx++;
251 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
252 		idx++;
253 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
254 		idx++;
255 		buf[idx] = (req->u.dpcd_read.num_bytes);
256 		idx++;
257 		break;
258 
259 	case DP_REMOTE_DPCD_WRITE:
260 		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
261 		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
262 		idx++;
263 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
264 		idx++;
265 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
266 		idx++;
267 		buf[idx] = (req->u.dpcd_write.num_bytes);
268 		idx++;
269 		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
270 		idx += req->u.dpcd_write.num_bytes;
271 		break;
272 	case DP_REMOTE_I2C_READ:
273 		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
274 		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
275 		idx++;
276 		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
277 			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
278 			idx++;
279 			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
280 			idx++;
281 			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
282 			idx += req->u.i2c_read.transactions[i].num_bytes;
283 
284 			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 5;
285 			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
286 			idx++;
287 		}
288 		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
289 		idx++;
290 		buf[idx] = (req->u.i2c_read.num_bytes_read);
291 		idx++;
292 		break;
293 
294 	case DP_REMOTE_I2C_WRITE:
295 		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
296 		idx++;
297 		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
298 		idx++;
299 		buf[idx] = (req->u.i2c_write.num_bytes);
300 		idx++;
301 		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
302 		idx += req->u.i2c_write.num_bytes;
303 		break;
304 	}
305 	raw->cur_len = idx;
306 }
307 
308 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
309 {
310 	u8 crc4;
311 	crc4 = drm_dp_msg_data_crc4(msg, len);
312 	msg[len] = crc4;
313 }
314 
315 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
316 					 struct drm_dp_sideband_msg_tx *raw)
317 {
318 	int idx = 0;
319 	u8 *buf = raw->msg;
320 
321 	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
322 
323 	raw->cur_len = idx;
324 }
325 
326 /* this adds a chunk of msg to the builder to get the final msg */
327 static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
328 				      u8 *replybuf, u8 replybuflen, bool hdr)
329 {
330 	int ret;
331 	u8 crc4 __unused;	/* XXX Mistake?  */
332 
333 	if (hdr) {
334 		u8 hdrlen;
335 		struct drm_dp_sideband_msg_hdr recv_hdr;
336 		ret = drm_dp_decode_sideband_msg_hdr(&recv_hdr, replybuf, replybuflen, &hdrlen);
337 		if (ret == false) {
338 			print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, 1, replybuf, replybuflen, false);
339 			return false;
340 		}
341 
342 		/*
343 		 * ignore out-of-order messages or messages that are part of a
344 		 * failed transaction
345 		 */
346 		if (!recv_hdr.somt && !msg->have_somt)
347 			return false;
348 
349 		/* get length contained in this portion */
350 		msg->curchunk_len = recv_hdr.msg_len;
351 		msg->curchunk_hdrlen = hdrlen;
352 
353 		/* we have already gotten an somt - don't bother parsing */
354 		if (recv_hdr.somt && msg->have_somt)
355 			return false;
356 
357 		if (recv_hdr.somt) {
358 			memcpy(&msg->initial_hdr, &recv_hdr, sizeof(struct drm_dp_sideband_msg_hdr));
359 			msg->have_somt = true;
360 		}
361 		if (recv_hdr.eomt)
362 			msg->have_eomt = true;
363 
364 		/* copy the bytes for the remainder of this header chunk */
365 		msg->curchunk_idx = min(msg->curchunk_len, (u8)(replybuflen - hdrlen));
366 		memcpy(&msg->chunk[0], replybuf + hdrlen, msg->curchunk_idx);
367 	} else {
368 		memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
369 		msg->curchunk_idx += replybuflen;
370 	}
371 
372 	if (msg->curchunk_idx >= msg->curchunk_len) {
373 		/* do CRC */
374 		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
375 		/* copy chunk into bigger msg */
376 		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
377 		msg->curlen += msg->curchunk_len - 1;
378 	}
379 	return true;
380 }
381 
382 static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
383 					       struct drm_dp_sideband_msg_reply_body *repmsg)
384 {
385 	int idx = 1;
386 	int i;
387 	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
388 	idx += 16;
389 	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
390 	idx++;
391 	if (idx > raw->curlen)
392 		goto fail_len;
393 	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
394 		if (raw->msg[idx] & 0x80)
395 			repmsg->u.link_addr.ports[i].input_port = 1;
396 
397 		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
398 		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
399 
400 		idx++;
401 		if (idx > raw->curlen)
402 			goto fail_len;
403 		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
404 		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
405 		if (repmsg->u.link_addr.ports[i].input_port == 0)
406 			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
407 		idx++;
408 		if (idx > raw->curlen)
409 			goto fail_len;
410 		if (repmsg->u.link_addr.ports[i].input_port == 0) {
411 			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
412 			idx++;
413 			if (idx > raw->curlen)
414 				goto fail_len;
415 			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
416 			idx += 16;
417 			if (idx > raw->curlen)
418 				goto fail_len;
419 			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
420 			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
421 			idx++;
422 
423 		}
424 		if (idx > raw->curlen)
425 			goto fail_len;
426 	}
427 
428 	return true;
429 fail_len:
430 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
431 	return false;
432 }
433 
434 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
435 						   struct drm_dp_sideband_msg_reply_body *repmsg)
436 {
437 	int idx = 1;
438 	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
439 	idx++;
440 	if (idx > raw->curlen)
441 		goto fail_len;
442 	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
443 	if (idx > raw->curlen)
444 		goto fail_len;
445 
446 	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
447 	return true;
448 fail_len:
449 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
450 	return false;
451 }
452 
453 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
454 						      struct drm_dp_sideband_msg_reply_body *repmsg)
455 {
456 	int idx = 1;
457 	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
458 	idx++;
459 	if (idx > raw->curlen)
460 		goto fail_len;
461 	return true;
462 fail_len:
463 	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
464 	return false;
465 }
466 
467 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
468 						      struct drm_dp_sideband_msg_reply_body *repmsg)
469 {
470 	int idx = 1;
471 
472 	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
473 	idx++;
474 	if (idx > raw->curlen)
475 		goto fail_len;
476 	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
477 	idx++;
478 	/* TODO check */
479 	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
480 	return true;
481 fail_len:
482 	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
483 	return false;
484 }
485 
486 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
487 							  struct drm_dp_sideband_msg_reply_body *repmsg)
488 {
489 	int idx = 1;
490 	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
491 	idx++;
492 	if (idx > raw->curlen)
493 		goto fail_len;
494 	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
495 	idx += 2;
496 	if (idx > raw->curlen)
497 		goto fail_len;
498 	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
499 	idx += 2;
500 	if (idx > raw->curlen)
501 		goto fail_len;
502 	return true;
503 fail_len:
504 	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
505 	return false;
506 }
507 
508 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
509 							  struct drm_dp_sideband_msg_reply_body *repmsg)
510 {
511 	int idx = 1;
512 	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
513 	idx++;
514 	if (idx > raw->curlen)
515 		goto fail_len;
516 	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
517 	idx++;
518 	if (idx > raw->curlen)
519 		goto fail_len;
520 	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
521 	idx += 2;
522 	if (idx > raw->curlen)
523 		goto fail_len;
524 	return true;
525 fail_len:
526 	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
527 	return false;
528 }
529 
530 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
531 						    struct drm_dp_sideband_msg_reply_body *repmsg)
532 {
533 	int idx = 1;
534 	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
535 	idx++;
536 	if (idx > raw->curlen)
537 		goto fail_len;
538 	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
539 	idx += 2;
540 	if (idx > raw->curlen)
541 		goto fail_len;
542 	return true;
543 fail_len:
544 	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
545 	return false;
546 }
547 
548 static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
549 					struct drm_dp_sideband_msg_reply_body *msg)
550 {
551 	memset(msg, 0, sizeof(*msg));
552 	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
553 	msg->req_type = (raw->msg[0] & 0x7f);
554 
555 	if (msg->reply_type) {
556 		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
557 		msg->u.nak.reason = raw->msg[17];
558 		msg->u.nak.nak_data = raw->msg[18];
559 		return false;
560 	}
561 
562 	switch (msg->req_type) {
563 	case DP_LINK_ADDRESS:
564 		return drm_dp_sideband_parse_link_address(raw, msg);
565 	case DP_QUERY_PAYLOAD:
566 		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
567 	case DP_REMOTE_DPCD_READ:
568 		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
569 	case DP_REMOTE_DPCD_WRITE:
570 		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
571 	case DP_REMOTE_I2C_READ:
572 		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
573 	case DP_ENUM_PATH_RESOURCES:
574 		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
575 	case DP_ALLOCATE_PAYLOAD:
576 		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
577 	default:
578 		DRM_ERROR("Got unknown reply 0x%02x\n", msg->req_type);
579 		return false;
580 	}
581 }
582 
583 static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
584 							   struct drm_dp_sideband_msg_req_body *msg)
585 {
586 	int idx = 1;
587 
588 	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
589 	idx++;
590 	if (idx > raw->curlen)
591 		goto fail_len;
592 
593 	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
594 	idx += 16;
595 	if (idx > raw->curlen)
596 		goto fail_len;
597 
598 	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
599 	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
600 	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
601 	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
602 	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
603 	idx++;
604 	return true;
605 fail_len:
606 	DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
607 	return false;
608 }
609 
610 static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
611 							   struct drm_dp_sideband_msg_req_body *msg)
612 {
613 	int idx = 1;
614 
615 	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
616 	idx++;
617 	if (idx > raw->curlen)
618 		goto fail_len;
619 
620 	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
621 	idx += 16;
622 	if (idx > raw->curlen)
623 		goto fail_len;
624 
625 	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
626 	idx++;
627 	return true;
628 fail_len:
629 	DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
630 	return false;
631 }
632 
633 static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
634 				      struct drm_dp_sideband_msg_req_body *msg)
635 {
636 	memset(msg, 0, sizeof(*msg));
637 	msg->req_type = (raw->msg[0] & 0x7f);
638 
639 	switch (msg->req_type) {
640 	case DP_CONNECTION_STATUS_NOTIFY:
641 		return drm_dp_sideband_parse_connection_status_notify(raw, msg);
642 	case DP_RESOURCE_STATUS_NOTIFY:
643 		return drm_dp_sideband_parse_resource_status_notify(raw, msg);
644 	default:
645 		DRM_ERROR("Got unknown request 0x%02x\n", msg->req_type);
646 		return false;
647 	}
648 }
649 
650 static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
651 {
652 	struct drm_dp_sideband_msg_req_body req;
653 
654 	req.req_type = DP_REMOTE_DPCD_WRITE;
655 	req.u.dpcd_write.port_number = port_num;
656 	req.u.dpcd_write.dpcd_address = offset;
657 	req.u.dpcd_write.num_bytes = num_bytes;
658 	req.u.dpcd_write.bytes = bytes;
659 	drm_dp_encode_sideband_req(&req, msg);
660 
661 	return 0;
662 }
663 
664 static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
665 {
666 	struct drm_dp_sideband_msg_req_body req;
667 
668 	req.req_type = DP_LINK_ADDRESS;
669 	drm_dp_encode_sideband_req(&req, msg);
670 	return 0;
671 }
672 
673 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
674 {
675 	struct drm_dp_sideband_msg_req_body req;
676 
677 	req.req_type = DP_ENUM_PATH_RESOURCES;
678 	req.u.port_num.port_number = port_num;
679 	drm_dp_encode_sideband_req(&req, msg);
680 	msg->path_msg = true;
681 	return 0;
682 }
683 
684 static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
685 				  u8 vcpi, uint16_t pbn)
686 {
687 	struct drm_dp_sideband_msg_req_body req;
688 	memset(&req, 0, sizeof(req));
689 	req.req_type = DP_ALLOCATE_PAYLOAD;
690 	req.u.allocate_payload.port_number = port_num;
691 	req.u.allocate_payload.vcpi = vcpi;
692 	req.u.allocate_payload.pbn = pbn;
693 	drm_dp_encode_sideband_req(&req, msg);
694 	msg->path_msg = true;
695 	return 0;
696 }
697 
698 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
699 					struct drm_dp_vcpi *vcpi)
700 {
701 	int ret, vcpi_ret;
702 
703 	mutex_lock(&mgr->payload_lock);
704 	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
705 	if (ret > mgr->max_payloads) {
706 		ret = -EINVAL;
707 		DRM_DEBUG_KMS("out of payload ids %d\n", ret);
708 		goto out_unlock;
709 	}
710 
711 	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
712 	if (vcpi_ret > mgr->max_payloads) {
713 		ret = -EINVAL;
714 		DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
715 		goto out_unlock;
716 	}
717 
718 	set_bit(ret, &mgr->payload_mask);
719 	set_bit(vcpi_ret, &mgr->vcpi_mask);
720 	vcpi->vcpi = vcpi_ret + 1;
721 	mgr->proposed_vcpis[ret - 1] = vcpi;
722 out_unlock:
723 	mutex_unlock(&mgr->payload_lock);
724 	return ret;
725 }
726 
727 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
728 				      int vcpi)
729 {
730 	int i;
731 	if (vcpi == 0)
732 		return;
733 
734 	mutex_lock(&mgr->payload_lock);
735 	DRM_DEBUG_KMS("putting payload %d\n", vcpi);
736 	clear_bit(vcpi - 1, &mgr->vcpi_mask);
737 
738 	for (i = 0; i < mgr->max_payloads; i++) {
739 		if (mgr->proposed_vcpis[i])
740 			if (mgr->proposed_vcpis[i]->vcpi == vcpi) {
741 				mgr->proposed_vcpis[i] = NULL;
742 				clear_bit(i + 1, &mgr->payload_mask);
743 			}
744 	}
745 	mutex_unlock(&mgr->payload_lock);
746 }
747 
748 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
749 			      struct drm_dp_sideband_msg_tx *txmsg)
750 {
751 	bool ret;
752 
753 	/*
754 	 * All updates to txmsg->state are protected by mgr->qlock, and the two
755 	 * cases we check here are terminal states. For those the barriers
756 	 * provided by the wake_up/wait_event pair are enough.
757 	 */
758 	ret = (txmsg->state == DRM_DP_SIDEBAND_TX_RX ||
759 	       txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT);
760 	return ret;
761 }
762 
763 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
764 				    struct drm_dp_sideband_msg_tx *txmsg)
765 {
766 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
767 	int ret;
768 
769 #ifdef __NetBSD__
770 	mutex_lock(&mstb->mgr->qlock);
771 	DRM_TIMED_WAIT_UNTIL(ret, &mgr->tx_waitq, &mstb->mgr->qlock, 4*HZ,
772 	    check_txmsg_state(mgr, txmsg));
773 #else
774 	ret = wait_event_timeout(mgr->tx_waitq,
775 				 check_txmsg_state(mgr, txmsg),
776 				 (4 * HZ));
777 	mutex_lock(&mstb->mgr->qlock);
778 #endif
779 	if (ret > 0) {
780 		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
781 			ret = -EIO;
782 			goto out;
783 		}
784 	} else {
785 		DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
786 
787 		/* dump some state */
788 		ret = -EIO;
789 
790 		/* remove from q */
791 		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
792 		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND) {
793 			list_del(&txmsg->next);
794 		}
795 
796 		if (txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
797 		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
798 			mstb->tx_slots[txmsg->seqno] = NULL;
799 		}
800 	}
801 out:
802 	mutex_unlock(&mgr->qlock);
803 
804 	return ret;
805 }
806 
807 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
808 {
809 	struct drm_dp_mst_branch *mstb;
810 
811 	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
812 	if (!mstb)
813 		return NULL;
814 
815 	mstb->lct = lct;
816 	if (lct > 1)
817 		memcpy(mstb->rad, rad, lct / 2);
818 	INIT_LIST_HEAD(&mstb->ports);
819 	kref_init(&mstb->kref);
820 	return mstb;
821 }
822 
823 static void drm_dp_free_mst_port(struct kref *kref);
824 
825 static void drm_dp_free_mst_branch_device(struct kref *kref)
826 {
827 	struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
828 	if (mstb->port_parent) {
829 		if (list_empty(&mstb->port_parent->next))
830 			kref_put(&mstb->port_parent->kref, drm_dp_free_mst_port);
831 	}
832 	kfree(mstb);
833 }
834 
835 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
836 {
837 	struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
838 	struct drm_dp_mst_port *port, *tmp;
839 	bool wake_tx = false;
840 
841 	/*
842 	 * init kref again to be used by ports to remove mst branch when it is
843 	 * not needed anymore
844 	 */
845 	kref_init(kref);
846 
847 	if (mstb->port_parent && list_empty(&mstb->port_parent->next))
848 		kref_get(&mstb->port_parent->kref);
849 
850 	/*
851 	 * destroy all ports - don't need lock
852 	 * as there are no more references to the mst branch
853 	 * device at this point.
854 	 */
855 	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
856 		list_del(&port->next);
857 		drm_dp_put_port(port);
858 	}
859 
860 	/* drop any tx slots msg */
861 	mutex_lock(&mstb->mgr->qlock);
862 	if (mstb->tx_slots[0]) {
863 		mstb->tx_slots[0]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
864 		mstb->tx_slots[0] = NULL;
865 		wake_tx = true;
866 	}
867 	if (mstb->tx_slots[1]) {
868 		mstb->tx_slots[1]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
869 		mstb->tx_slots[1] = NULL;
870 		wake_tx = true;
871 	}
872 #ifdef __NetBSD__
873 	if (wake_tx)
874 		DRM_WAKEUP_ONE(&mstb->mgr->tx_waitq, &mstb->mgr->qlock);
875 	mutex_unlock(&mstb->mgr->qlock);
876 #else
877 	mutex_unlock(&mstb->mgr->qlock);
878 
879 	if (wake_tx)
880 		wake_up(&mstb->mgr->tx_waitq);
881 #endif
882 
883 	kref_put(kref, drm_dp_free_mst_branch_device);
884 }
885 
886 static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb)
887 {
888 	kref_put(&mstb->kref, drm_dp_destroy_mst_branch_device);
889 }
890 
891 
892 static void drm_dp_port_teardown_pdt(struct drm_dp_mst_port *port, int old_pdt)
893 {
894 	struct drm_dp_mst_branch *mstb;
895 
896 	switch (old_pdt) {
897 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
898 	case DP_PEER_DEVICE_SST_SINK:
899 		/* remove i2c over sideband */
900 		drm_dp_mst_unregister_i2c_bus(&port->aux);
901 		break;
902 	case DP_PEER_DEVICE_MST_BRANCHING:
903 		mstb = port->mstb;
904 		port->mstb = NULL;
905 		drm_dp_put_mst_branch_device(mstb);
906 		break;
907 	}
908 }
909 
910 static void drm_dp_destroy_port(struct kref *kref)
911 {
912 	struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
913 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
914 
915 	if (!port->input) {
916 		port->vcpi.num_slots = 0;
917 
918 		kfree(port->cached_edid);
919 
920 		/*
921 		 * The only time we don't have a connector
922 		 * on an output port is if the connector init
923 		 * fails.
924 		 */
925 		if (port->connector) {
926 			/* we can't destroy the connector here, as
927 			 * we might be holding the mode_config.mutex
928 			 * from an EDID retrieval */
929 
930 			mutex_lock(&mgr->destroy_connector_lock);
931 			kref_get(&port->parent->kref);
932 			list_add(&port->next, &mgr->destroy_connector_list);
933 			mutex_unlock(&mgr->destroy_connector_lock);
934 			schedule_work(&mgr->destroy_connector_work);
935 			return;
936 		}
937 		/* no need to clean up vcpi
938 		 * as if we have no connector we never setup a vcpi */
939 		drm_dp_port_teardown_pdt(port, port->pdt);
940 		port->pdt = DP_PEER_DEVICE_NONE;
941 	}
942 	kfree(port);
943 }
944 
945 static void drm_dp_put_port(struct drm_dp_mst_port *port)
946 {
947 	kref_put(&port->kref, drm_dp_destroy_port);
948 }
949 
950 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)
951 {
952 	struct drm_dp_mst_port *port;
953 	struct drm_dp_mst_branch *rmstb;
954 	if (to_find == mstb) {
955 		kref_get(&mstb->kref);
956 		return mstb;
957 	}
958 	list_for_each_entry(port, &mstb->ports, next) {
959 		if (port->mstb) {
960 			rmstb = drm_dp_mst_get_validated_mstb_ref_locked(port->mstb, to_find);
961 			if (rmstb)
962 				return rmstb;
963 		}
964 	}
965 	return NULL;
966 }
967 
968 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)
969 {
970 	struct drm_dp_mst_branch *rmstb = NULL;
971 	mutex_lock(&mgr->lock);
972 	if (mgr->mst_primary)
973 		rmstb = drm_dp_mst_get_validated_mstb_ref_locked(mgr->mst_primary, mstb);
974 	mutex_unlock(&mgr->lock);
975 	return rmstb;
976 }
977 
978 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)
979 {
980 	struct drm_dp_mst_port *port, *mport;
981 
982 	list_for_each_entry(port, &mstb->ports, next) {
983 		if (port == to_find) {
984 			kref_get(&port->kref);
985 			return port;
986 		}
987 		if (port->mstb) {
988 			mport = drm_dp_mst_get_port_ref_locked(port->mstb, to_find);
989 			if (mport)
990 				return mport;
991 		}
992 	}
993 	return NULL;
994 }
995 
996 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)
997 {
998 	struct drm_dp_mst_port *rport = NULL;
999 	mutex_lock(&mgr->lock);
1000 	if (mgr->mst_primary)
1001 		rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port);
1002 	mutex_unlock(&mgr->lock);
1003 	return rport;
1004 }
1005 
1006 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
1007 {
1008 	struct drm_dp_mst_port *port;
1009 
1010 	list_for_each_entry(port, &mstb->ports, next) {
1011 		if (port->port_num == port_num) {
1012 			kref_get(&port->kref);
1013 			return port;
1014 		}
1015 	}
1016 
1017 	return NULL;
1018 }
1019 
1020 /*
1021  * calculate a new RAD for this MST branch device
1022  * if parent has an LCT of 2 then it has 1 nibble of RAD,
1023  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
1024  */
1025 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
1026 				 u8 *rad)
1027 {
1028 	int parent_lct = port->parent->lct;
1029 	int shift = 4;
1030 	int idx = (parent_lct - 1) / 2;
1031 	if (parent_lct > 1) {
1032 		memcpy(rad, port->parent->rad, idx + 1);
1033 		shift = (parent_lct % 2) ? 4 : 0;
1034 	} else
1035 		rad[0] = 0;
1036 
1037 	rad[idx] |= port->port_num << shift;
1038 	return parent_lct + 1;
1039 }
1040 
1041 /*
1042  * return sends link address for new mstb
1043  */
1044 static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
1045 {
1046 	int ret __unused;
1047 	u8 rad[6], lct;
1048 	bool send_link = false;
1049 	switch (port->pdt) {
1050 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
1051 	case DP_PEER_DEVICE_SST_SINK:
1052 		/* add i2c over sideband */
1053 		ret = drm_dp_mst_register_i2c_bus(&port->aux);
1054 		break;
1055 	case DP_PEER_DEVICE_MST_BRANCHING:
1056 		lct = drm_dp_calculate_rad(port, rad);
1057 
1058 		port->mstb = drm_dp_add_mst_branch_device(lct, rad);
1059 		port->mstb->mgr = port->mgr;
1060 		port->mstb->port_parent = port;
1061 
1062 		send_link = true;
1063 		break;
1064 	}
1065 	return send_link;
1066 }
1067 
1068 static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
1069 {
1070 	int ret __unused;
1071 
1072 	memcpy(mstb->guid, guid, 16);
1073 
1074 	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
1075 		if (mstb->port_parent) {
1076 			ret = drm_dp_send_dpcd_write(
1077 					mstb->mgr,
1078 					mstb->port_parent,
1079 					DP_GUID,
1080 					16,
1081 					mstb->guid);
1082 		} else {
1083 
1084 			ret = drm_dp_dpcd_write(
1085 					mstb->mgr->aux,
1086 					DP_GUID,
1087 					mstb->guid,
1088 					16);
1089 		}
1090 	}
1091 }
1092 
1093 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
1094 				int pnum,
1095 				char *proppath,
1096 				size_t proppath_size)
1097 {
1098 	int i;
1099 	char temp[8];
1100 	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
1101 	for (i = 0; i < (mstb->lct - 1); i++) {
1102 		int shift = (i % 2) ? 0 : 4;
1103 		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
1104 		snprintf(temp, sizeof(temp), "-%d", port_num);
1105 		strlcat(proppath, temp, proppath_size);
1106 	}
1107 	snprintf(temp, sizeof(temp), "-%d", pnum);
1108 	strlcat(proppath, temp, proppath_size);
1109 }
1110 
1111 static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
1112 			    struct device *dev,
1113 			    struct drm_dp_link_addr_reply_port *port_msg)
1114 {
1115 	struct drm_dp_mst_port *port;
1116 	bool ret;
1117 	bool created = false;
1118 	int old_pdt = 0;
1119 	int old_ddps = 0;
1120 	port = drm_dp_get_port(mstb, port_msg->port_number);
1121 	if (!port) {
1122 		port = kzalloc(sizeof(*port), GFP_KERNEL);
1123 		if (!port)
1124 			return;
1125 		kref_init(&port->kref);
1126 		port->parent = mstb;
1127 		port->port_num = port_msg->port_number;
1128 		port->mgr = mstb->mgr;
1129 		port->aux.name = "DPMST";
1130 		port->aux.dev = dev;
1131 		created = true;
1132 	} else {
1133 		old_pdt = port->pdt;
1134 		old_ddps = port->ddps;
1135 	}
1136 
1137 	port->pdt = port_msg->peer_device_type;
1138 	port->input = port_msg->input_port;
1139 	port->mcs = port_msg->mcs;
1140 	port->ddps = port_msg->ddps;
1141 	port->ldps = port_msg->legacy_device_plug_status;
1142 	port->dpcd_rev = port_msg->dpcd_revision;
1143 	port->num_sdp_streams = port_msg->num_sdp_streams;
1144 	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
1145 
1146 	/* manage mstb port lists with mgr lock - take a reference
1147 	   for this list */
1148 	if (created) {
1149 		mutex_lock(&mstb->mgr->lock);
1150 		kref_get(&port->kref);
1151 		list_add(&port->next, &mstb->ports);
1152 		mutex_unlock(&mstb->mgr->lock);
1153 	}
1154 
1155 	if (old_ddps != port->ddps) {
1156 		if (port->ddps) {
1157 			if (!port->input)
1158 				drm_dp_send_enum_path_resources(mstb->mgr, mstb, port);
1159 		} else {
1160 			port->available_pbn = 0;
1161 			}
1162 	}
1163 
1164 	if (old_pdt != port->pdt && !port->input) {
1165 		drm_dp_port_teardown_pdt(port, old_pdt);
1166 
1167 		ret = drm_dp_port_setup_pdt(port);
1168 		if (ret == true)
1169 			drm_dp_send_link_address(mstb->mgr, port->mstb);
1170 	}
1171 
1172 	if (created && !port->input) {
1173 		char proppath[255];
1174 
1175 		build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
1176 		port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, proppath);
1177 		if (!port->connector) {
1178 			/* remove it from the port list */
1179 			mutex_lock(&mstb->mgr->lock);
1180 			list_del(&port->next);
1181 			mutex_unlock(&mstb->mgr->lock);
1182 			/* drop port list reference */
1183 			drm_dp_put_port(port);
1184 			goto out;
1185 		}
1186 		if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||
1187 		     port->pdt == DP_PEER_DEVICE_SST_SINK) &&
1188 		    port->port_num >= DP_MST_LOGICAL_PORT_0) {
1189 			port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
1190 			drm_mode_connector_set_tile_property(port->connector);
1191 		}
1192 		(*mstb->mgr->cbs->register_connector)(port->connector);
1193 	}
1194 
1195 out:
1196 	/* put reference to this port */
1197 	drm_dp_put_port(port);
1198 }
1199 
1200 static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
1201 			       struct drm_dp_connection_status_notify *conn_stat)
1202 {
1203 	struct drm_dp_mst_port *port;
1204 	int old_pdt;
1205 	int old_ddps;
1206 	bool dowork = false;
1207 	port = drm_dp_get_port(mstb, conn_stat->port_number);
1208 	if (!port)
1209 		return;
1210 
1211 	old_ddps = port->ddps;
1212 	old_pdt = port->pdt;
1213 	port->pdt = conn_stat->peer_device_type;
1214 	port->mcs = conn_stat->message_capability_status;
1215 	port->ldps = conn_stat->legacy_device_plug_status;
1216 	port->ddps = conn_stat->displayport_device_plug_status;
1217 
1218 	if (old_ddps != port->ddps) {
1219 		if (port->ddps) {
1220 			dowork = true;
1221 		} else {
1222 			port->available_pbn = 0;
1223 		}
1224 	}
1225 	if (old_pdt != port->pdt && !port->input) {
1226 		drm_dp_port_teardown_pdt(port, old_pdt);
1227 
1228 		if (drm_dp_port_setup_pdt(port))
1229 			dowork = true;
1230 	}
1231 
1232 	drm_dp_put_port(port);
1233 	if (dowork)
1234 		queue_work(system_long_wq, &mstb->mgr->work);
1235 
1236 }
1237 
1238 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
1239 							       u8 lct, u8 *rad)
1240 {
1241 	struct drm_dp_mst_branch *mstb;
1242 	struct drm_dp_mst_port *port;
1243 	int i;
1244 	/* find the port by iterating down */
1245 
1246 	mutex_lock(&mgr->lock);
1247 	mstb = mgr->mst_primary;
1248 
1249 	for (i = 0; i < lct - 1; i++) {
1250 		int shift = (i % 2) ? 0 : 4;
1251 		int port_num = (rad[i / 2] >> shift) & 0xf;
1252 
1253 		list_for_each_entry(port, &mstb->ports, next) {
1254 			if (port->port_num == port_num) {
1255 				mstb = port->mstb;
1256 				if (!mstb) {
1257 					DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
1258 					goto out;
1259 				}
1260 
1261 				break;
1262 			}
1263 		}
1264 	}
1265 	kref_get(&mstb->kref);
1266 out:
1267 	mutex_unlock(&mgr->lock);
1268 	return mstb;
1269 }
1270 
1271 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
1272 	struct drm_dp_mst_branch *mstb,
1273 	uint8_t *guid)
1274 {
1275 	struct drm_dp_mst_branch *found_mstb;
1276 	struct drm_dp_mst_port *port;
1277 
1278 	if (memcmp(mstb->guid, guid, 16) == 0)
1279 		return mstb;
1280 
1281 
1282 	list_for_each_entry(port, &mstb->ports, next) {
1283 		if (!port->mstb)
1284 			continue;
1285 
1286 		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
1287 
1288 		if (found_mstb)
1289 			return found_mstb;
1290 	}
1291 
1292 	return NULL;
1293 }
1294 
1295 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid(
1296 	struct drm_dp_mst_topology_mgr *mgr,
1297 	uint8_t *guid)
1298 {
1299 	struct drm_dp_mst_branch *mstb;
1300 
1301 	/* find the port by iterating down */
1302 	mutex_lock(&mgr->lock);
1303 
1304 	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
1305 
1306 	if (mstb)
1307 		kref_get(&mstb->kref);
1308 
1309 	mutex_unlock(&mgr->lock);
1310 	return mstb;
1311 }
1312 
1313 static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1314 					       struct drm_dp_mst_branch *mstb)
1315 {
1316 	struct drm_dp_mst_port *port;
1317 	struct drm_dp_mst_branch *mstb_child;
1318 	if (!mstb->link_address_sent)
1319 		drm_dp_send_link_address(mgr, mstb);
1320 
1321 	list_for_each_entry(port, &mstb->ports, next) {
1322 		if (port->input)
1323 			continue;
1324 
1325 		if (!port->ddps)
1326 			continue;
1327 
1328 		if (!port->available_pbn)
1329 			drm_dp_send_enum_path_resources(mgr, mstb, port);
1330 
1331 		if (port->mstb) {
1332 			mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb);
1333 			if (mstb_child) {
1334 				drm_dp_check_and_send_link_address(mgr, mstb_child);
1335 				drm_dp_put_mst_branch_device(mstb_child);
1336 			}
1337 		}
1338 	}
1339 }
1340 
1341 static void drm_dp_mst_link_probe_work(struct work_struct *work)
1342 {
1343 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
1344 	struct drm_dp_mst_branch *mstb;
1345 
1346 	mutex_lock(&mgr->lock);
1347 	mstb = mgr->mst_primary;
1348 	if (mstb) {
1349 		kref_get(&mstb->kref);
1350 	}
1351 	mutex_unlock(&mgr->lock);
1352 	if (mstb) {
1353 		drm_dp_check_and_send_link_address(mgr, mstb);
1354 		drm_dp_put_mst_branch_device(mstb);
1355 	}
1356 }
1357 
1358 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
1359 				 u8 *guid)
1360 {
1361 	static u8 zero_guid[16];
1362 
1363 	if (!memcmp(guid, zero_guid, 16)) {
1364 		u64 salt = get_jiffies_64();
1365 		memcpy(&guid[0], &salt, sizeof(u64));
1366 		memcpy(&guid[8], &salt, sizeof(u64));
1367 		return false;
1368 	}
1369 	return true;
1370 }
1371 
1372 #if 0
1373 static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
1374 {
1375 	struct drm_dp_sideband_msg_req_body req;
1376 
1377 	req.req_type = DP_REMOTE_DPCD_READ;
1378 	req.u.dpcd_read.port_number = port_num;
1379 	req.u.dpcd_read.dpcd_address = offset;
1380 	req.u.dpcd_read.num_bytes = num_bytes;
1381 	drm_dp_encode_sideband_req(&req, msg);
1382 
1383 	return 0;
1384 }
1385 #endif
1386 
1387 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
1388 				    bool up, u8 *msg, int len)
1389 {
1390 	int ret;
1391 	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
1392 	int tosend, total, offset;
1393 	int retries = 0;
1394 
1395 retry:
1396 	total = len;
1397 	offset = 0;
1398 	do {
1399 		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
1400 
1401 		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
1402 					&msg[offset],
1403 					tosend);
1404 		if (ret != tosend) {
1405 			if (ret == -EIO && retries < 5) {
1406 				retries++;
1407 				goto retry;
1408 			}
1409 			DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
1410 
1411 			return -EIO;
1412 		}
1413 		offset += tosend;
1414 		total -= tosend;
1415 	} while (total > 0);
1416 	return 0;
1417 }
1418 
1419 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
1420 				  struct drm_dp_sideband_msg_tx *txmsg)
1421 {
1422 	struct drm_dp_mst_branch *mstb = txmsg->dst;
1423 	u8 req_type;
1424 
1425 	/* both msg slots are full */
1426 	if (txmsg->seqno == -1) {
1427 		if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
1428 			DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
1429 			return -EAGAIN;
1430 		}
1431 		if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
1432 			txmsg->seqno = mstb->last_seqno;
1433 			mstb->last_seqno ^= 1;
1434 		} else if (mstb->tx_slots[0] == NULL)
1435 			txmsg->seqno = 0;
1436 		else
1437 			txmsg->seqno = 1;
1438 		mstb->tx_slots[txmsg->seqno] = txmsg;
1439 	}
1440 
1441 	req_type = txmsg->msg[0] & 0x7f;
1442 	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
1443 		req_type == DP_RESOURCE_STATUS_NOTIFY)
1444 		hdr->broadcast = 1;
1445 	else
1446 		hdr->broadcast = 0;
1447 	hdr->path_msg = txmsg->path_msg;
1448 	hdr->lct = mstb->lct;
1449 	hdr->lcr = mstb->lct - 1;
1450 	if (mstb->lct > 1)
1451 		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
1452 	hdr->seqno = txmsg->seqno;
1453 	return 0;
1454 }
1455 /*
1456  * process a single block of the next message in the sideband queue
1457  */
1458 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1459 				   struct drm_dp_sideband_msg_tx *txmsg,
1460 				   bool up)
1461 {
1462 	u8 chunk[48];
1463 	struct drm_dp_sideband_msg_hdr hdr;
1464 	int len, space, idx, tosend;
1465 	int ret;
1466 
1467 	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
1468 
1469 	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
1470 		txmsg->seqno = -1;
1471 		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
1472 	}
1473 
1474 	/* make hdr from dst mst - for replies use seqno
1475 	   otherwise assign one */
1476 	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
1477 	if (ret < 0)
1478 		return ret;
1479 
1480 	/* amount left to send in this message */
1481 	len = txmsg->cur_len - txmsg->cur_offset;
1482 
1483 	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
1484 	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
1485 
1486 	tosend = min(len, space);
1487 	if (len == txmsg->cur_len)
1488 		hdr.somt = 1;
1489 	if (space >= len)
1490 		hdr.eomt = 1;
1491 
1492 
1493 	hdr.msg_len = tosend + 1;
1494 	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
1495 	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
1496 	/* add crc at end */
1497 	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
1498 	idx += tosend + 1;
1499 
1500 	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
1501 	if (ret) {
1502 		DRM_DEBUG_KMS("sideband msg failed to send\n");
1503 		return ret;
1504 	}
1505 
1506 	txmsg->cur_offset += tosend;
1507 	if (txmsg->cur_offset == txmsg->cur_len) {
1508 		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
1509 		return 1;
1510 	}
1511 	return 0;
1512 }
1513 
1514 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
1515 {
1516 	struct drm_dp_sideband_msg_tx *txmsg;
1517 	int ret;
1518 
1519 	WARN_ON(!mutex_is_locked(&mgr->qlock));
1520 
1521 	/* construct a chunk from the first msg in the tx_msg queue */
1522 	if (list_empty(&mgr->tx_msg_downq)) {
1523 		mgr->tx_down_in_progress = false;
1524 		return;
1525 	}
1526 	mgr->tx_down_in_progress = true;
1527 
1528 	txmsg = list_first_entry(&mgr->tx_msg_downq, struct drm_dp_sideband_msg_tx, next);
1529 	ret = process_single_tx_qlock(mgr, txmsg, false);
1530 	if (ret == 1) {
1531 		/* txmsg is sent it should be in the slots now */
1532 		list_del(&txmsg->next);
1533 	} else if (ret) {
1534 		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1535 		list_del(&txmsg->next);
1536 		if (txmsg->seqno != -1)
1537 			txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1538 		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
1539 #ifdef __NetBSD__
1540 		DRM_WAKEUP_ONE(&mgr->tx_waitq, &mgr->qlock);
1541 #else
1542 		wake_up(&mgr->tx_waitq);
1543 #endif
1544 	}
1545 	if (list_empty(&mgr->tx_msg_downq)) {
1546 		mgr->tx_down_in_progress = false;
1547 		return;
1548 	}
1549 }
1550 
1551 /* called holding qlock */
1552 static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1553 				       struct drm_dp_sideband_msg_tx *txmsg)
1554 {
1555 	int ret;
1556 
1557 	/* construct a chunk from the first msg in the tx_msg queue */
1558 	ret = process_single_tx_qlock(mgr, txmsg, true);
1559 
1560 	if (ret != 1)
1561 		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1562 
1563 	txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1564 }
1565 
1566 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
1567 				 struct drm_dp_sideband_msg_tx *txmsg)
1568 {
1569 	mutex_lock(&mgr->qlock);
1570 	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
1571 	if (!mgr->tx_down_in_progress)
1572 		process_single_down_tx_qlock(mgr);
1573 	mutex_unlock(&mgr->qlock);
1574 }
1575 
1576 static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1577 				     struct drm_dp_mst_branch *mstb)
1578 {
1579 	int len __unused;
1580 	struct drm_dp_sideband_msg_tx *txmsg;
1581 	int ret;
1582 
1583 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1584 	if (!txmsg)
1585 		return;
1586 
1587 	txmsg->dst = mstb;
1588 	len = build_link_address(txmsg);
1589 
1590 	mstb->link_address_sent = true;
1591 	drm_dp_queue_down_tx(mgr, txmsg);
1592 
1593 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1594 	if (ret > 0) {
1595 		int i;
1596 
1597 		if (txmsg->reply.reply_type == 1)
1598 			DRM_DEBUG_KMS("link address nak received\n");
1599 		else {
1600 			DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
1601 			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1602 				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,
1603 				       txmsg->reply.u.link_addr.ports[i].input_port,
1604 				       txmsg->reply.u.link_addr.ports[i].peer_device_type,
1605 				       txmsg->reply.u.link_addr.ports[i].port_number,
1606 				       txmsg->reply.u.link_addr.ports[i].dpcd_revision,
1607 				       txmsg->reply.u.link_addr.ports[i].mcs,
1608 				       txmsg->reply.u.link_addr.ports[i].ddps,
1609 				       txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status,
1610 				       txmsg->reply.u.link_addr.ports[i].num_sdp_streams,
1611 				       txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks);
1612 			}
1613 
1614 			drm_dp_check_mstb_guid(mstb, txmsg->reply.u.link_addr.guid);
1615 
1616 			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1617 				drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
1618 			}
1619 			(*mgr->cbs->hotplug)(mgr);
1620 		}
1621 	} else {
1622 		mstb->link_address_sent = false;
1623 		DRM_DEBUG_KMS("link address failed %d\n", ret);
1624 	}
1625 
1626 	kfree(txmsg);
1627 }
1628 
1629 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
1630 					   struct drm_dp_mst_branch *mstb,
1631 					   struct drm_dp_mst_port *port)
1632 {
1633 	int len __unused;
1634 	struct drm_dp_sideband_msg_tx *txmsg;
1635 	int ret;
1636 
1637 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1638 	if (!txmsg)
1639 		return -ENOMEM;
1640 
1641 	txmsg->dst = mstb;
1642 	len = build_enum_path_resources(txmsg, port->port_num);
1643 
1644 	drm_dp_queue_down_tx(mgr, txmsg);
1645 
1646 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1647 	if (ret > 0) {
1648 		if (txmsg->reply.reply_type == 1)
1649 			DRM_DEBUG_KMS("enum path resources nak received\n");
1650 		else {
1651 			if (port->port_num != txmsg->reply.u.path_resources.port_number)
1652 				DRM_ERROR("got incorrect port in response\n");
1653 			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,
1654 			       txmsg->reply.u.path_resources.avail_payload_bw_number);
1655 			port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number;
1656 		}
1657 	}
1658 
1659 	kfree(txmsg);
1660 	return 0;
1661 }
1662 
1663 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
1664 {
1665 	if (!mstb->port_parent)
1666 		return NULL;
1667 
1668 	if (mstb->port_parent->mstb != mstb)
1669 		return mstb->port_parent;
1670 
1671 	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
1672 }
1673 
1674 static struct drm_dp_mst_branch *drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
1675 									 struct drm_dp_mst_branch *mstb,
1676 									 int *port_num)
1677 {
1678 	struct drm_dp_mst_branch *rmstb = NULL;
1679 	struct drm_dp_mst_port *found_port;
1680 	mutex_lock(&mgr->lock);
1681 	if (mgr->mst_primary) {
1682 		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
1683 
1684 		if (found_port) {
1685 			rmstb = found_port->parent;
1686 			kref_get(&rmstb->kref);
1687 			*port_num = found_port->port_num;
1688 		}
1689 	}
1690 	mutex_unlock(&mgr->lock);
1691 	return rmstb;
1692 }
1693 
1694 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
1695 				   struct drm_dp_mst_port *port,
1696 				   int id,
1697 				   int pbn)
1698 {
1699 	struct drm_dp_sideband_msg_tx *txmsg;
1700 	struct drm_dp_mst_branch *mstb;
1701 	int len __unused, ret, port_num;
1702 
1703 	port = drm_dp_get_validated_port_ref(mgr, port);
1704 	if (!port)
1705 		return -EINVAL;
1706 
1707 	port_num = port->port_num;
1708 	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1709 	if (!mstb) {
1710 		mstb = drm_dp_get_last_connected_port_and_mstb(mgr, port->parent, &port_num);
1711 
1712 		if (!mstb) {
1713 			drm_dp_put_port(port);
1714 			return -EINVAL;
1715 		}
1716 	}
1717 
1718 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1719 	if (!txmsg) {
1720 		ret = -ENOMEM;
1721 		goto fail_put;
1722 	}
1723 
1724 	txmsg->dst = mstb;
1725 	len = build_allocate_payload(txmsg, port_num,
1726 				     id,
1727 				     pbn);
1728 
1729 	drm_dp_queue_down_tx(mgr, txmsg);
1730 
1731 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1732 	if (ret > 0) {
1733 		if (txmsg->reply.reply_type == 1) {
1734 			ret = -EINVAL;
1735 		} else
1736 			ret = 0;
1737 	}
1738 	kfree(txmsg);
1739 fail_put:
1740 	drm_dp_put_mst_branch_device(mstb);
1741 	drm_dp_put_port(port);
1742 	return ret;
1743 }
1744 
1745 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1746 				       int id,
1747 				       struct drm_dp_payload *payload)
1748 {
1749 	int ret;
1750 
1751 	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
1752 	if (ret < 0) {
1753 		payload->payload_state = 0;
1754 		return ret;
1755 	}
1756 	payload->payload_state = DP_PAYLOAD_LOCAL;
1757 	return 0;
1758 }
1759 
1760 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1761 				       struct drm_dp_mst_port *port,
1762 				       int id,
1763 				       struct drm_dp_payload *payload)
1764 {
1765 	int ret;
1766 	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
1767 	if (ret < 0)
1768 		return ret;
1769 	payload->payload_state = DP_PAYLOAD_REMOTE;
1770 	return ret;
1771 }
1772 
1773 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1774 					struct drm_dp_mst_port *port,
1775 					int id,
1776 					struct drm_dp_payload *payload)
1777 {
1778 	DRM_DEBUG_KMS("\n");
1779 	/* its okay for these to fail */
1780 	if (port) {
1781 		drm_dp_payload_send_msg(mgr, port, id, 0);
1782 	}
1783 
1784 	drm_dp_dpcd_write_payload(mgr, id, payload);
1785 	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
1786 	return 0;
1787 }
1788 
1789 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1790 					int id,
1791 					struct drm_dp_payload *payload)
1792 {
1793 	payload->payload_state = 0;
1794 	return 0;
1795 }
1796 
1797 /**
1798  * drm_dp_update_payload_part1() - Execute payload update part 1
1799  * @mgr: manager to use.
1800  *
1801  * This iterates over all proposed virtual channels, and tries to
1802  * allocate space in the link for them. For 0->slots transitions,
1803  * this step just writes the VCPI to the MST device. For slots->0
1804  * transitions, this writes the updated VCPIs and removes the
1805  * remote VC payloads.
1806  *
1807  * after calling this the driver should generate ACT and payload
1808  * packets.
1809  */
1810 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
1811 {
1812 	int i, j;
1813 	int cur_slots = 1;
1814 	struct drm_dp_payload req_payload;
1815 	struct drm_dp_mst_port *port;
1816 
1817 	mutex_lock(&mgr->payload_lock);
1818 	for (i = 0; i < mgr->max_payloads; i++) {
1819 		/* solve the current payloads - compare to the hw ones
1820 		   - update the hw view */
1821 		req_payload.start_slot = cur_slots;
1822 		if (mgr->proposed_vcpis[i]) {
1823 			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1824 			port = drm_dp_get_validated_port_ref(mgr, port);
1825 			if (!port) {
1826 				mutex_unlock(&mgr->payload_lock);
1827 				return -EINVAL;
1828 			}
1829 			req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
1830 			req_payload.vcpi = mgr->proposed_vcpis[i]->vcpi;
1831 		} else {
1832 			port = NULL;
1833 			req_payload.num_slots = 0;
1834 		}
1835 
1836 		if (mgr->payloads[i].start_slot != req_payload.start_slot) {
1837 			mgr->payloads[i].start_slot = req_payload.start_slot;
1838 		}
1839 		/* work out what is required to happen with this payload */
1840 		if (mgr->payloads[i].num_slots != req_payload.num_slots) {
1841 
1842 			/* need to push an update for this payload */
1843 			if (req_payload.num_slots) {
1844 				drm_dp_create_payload_step1(mgr, mgr->proposed_vcpis[i]->vcpi, &req_payload);
1845 				mgr->payloads[i].num_slots = req_payload.num_slots;
1846 				mgr->payloads[i].vcpi = req_payload.vcpi;
1847 			} else if (mgr->payloads[i].num_slots) {
1848 				mgr->payloads[i].num_slots = 0;
1849 				drm_dp_destroy_payload_step1(mgr, port, mgr->payloads[i].vcpi, &mgr->payloads[i]);
1850 				req_payload.payload_state = mgr->payloads[i].payload_state;
1851 				mgr->payloads[i].start_slot = 0;
1852 			}
1853 			mgr->payloads[i].payload_state = req_payload.payload_state;
1854 		}
1855 		cur_slots += req_payload.num_slots;
1856 
1857 		if (port)
1858 			drm_dp_put_port(port);
1859 	}
1860 
1861 	for (i = 0; i < mgr->max_payloads; i++) {
1862 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1863 			DRM_DEBUG_KMS("removing payload %d\n", i);
1864 			for (j = i; j < mgr->max_payloads - 1; j++) {
1865 				memcpy(&mgr->payloads[j], &mgr->payloads[j + 1], sizeof(struct drm_dp_payload));
1866 				mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
1867 				if (mgr->proposed_vcpis[j] && mgr->proposed_vcpis[j]->num_slots) {
1868 					set_bit(j + 1, &mgr->payload_mask);
1869 				} else {
1870 					clear_bit(j + 1, &mgr->payload_mask);
1871 				}
1872 			}
1873 			memset(&mgr->payloads[mgr->max_payloads - 1], 0, sizeof(struct drm_dp_payload));
1874 			mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
1875 			clear_bit(mgr->max_payloads, &mgr->payload_mask);
1876 
1877 		}
1878 	}
1879 	mutex_unlock(&mgr->payload_lock);
1880 
1881 	return 0;
1882 }
1883 EXPORT_SYMBOL(drm_dp_update_payload_part1);
1884 
1885 /**
1886  * drm_dp_update_payload_part2() - Execute payload update part 2
1887  * @mgr: manager to use.
1888  *
1889  * This iterates over all proposed virtual channels, and tries to
1890  * allocate space in the link for them. For 0->slots transitions,
1891  * this step writes the remote VC payload commands. For slots->0
1892  * this just resets some internal state.
1893  */
1894 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
1895 {
1896 	struct drm_dp_mst_port *port;
1897 	int i;
1898 	int ret = 0;
1899 	mutex_lock(&mgr->payload_lock);
1900 	for (i = 0; i < mgr->max_payloads; i++) {
1901 
1902 		if (!mgr->proposed_vcpis[i])
1903 			continue;
1904 
1905 		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1906 
1907 		DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
1908 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
1909 			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1910 		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1911 			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1912 		}
1913 		if (ret) {
1914 			mutex_unlock(&mgr->payload_lock);
1915 			return ret;
1916 		}
1917 	}
1918 	mutex_unlock(&mgr->payload_lock);
1919 	return 0;
1920 }
1921 EXPORT_SYMBOL(drm_dp_update_payload_part2);
1922 
1923 #if 0 /* unused as of yet */
1924 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
1925 				 struct drm_dp_mst_port *port,
1926 				 int offset, int size)
1927 {
1928 	int len;
1929 	struct drm_dp_sideband_msg_tx *txmsg;
1930 
1931 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1932 	if (!txmsg)
1933 		return -ENOMEM;
1934 
1935 	len = build_dpcd_read(txmsg, port->port_num, 0, 8);
1936 	txmsg->dst = port->parent;
1937 
1938 	drm_dp_queue_down_tx(mgr, txmsg);
1939 
1940 	return 0;
1941 }
1942 #endif
1943 
1944 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
1945 				  struct drm_dp_mst_port *port,
1946 				  int offset, int size, u8 *bytes)
1947 {
1948 	int len __unused;
1949 	int ret;
1950 	struct drm_dp_sideband_msg_tx *txmsg;
1951 	struct drm_dp_mst_branch *mstb;
1952 
1953 	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1954 	if (!mstb)
1955 		return -EINVAL;
1956 
1957 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1958 	if (!txmsg) {
1959 		ret = -ENOMEM;
1960 		goto fail_put;
1961 	}
1962 
1963 	len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
1964 	txmsg->dst = mstb;
1965 
1966 	drm_dp_queue_down_tx(mgr, txmsg);
1967 
1968 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1969 	if (ret > 0) {
1970 		if (txmsg->reply.reply_type == 1) {
1971 			ret = -EINVAL;
1972 		} else
1973 			ret = 0;
1974 	}
1975 	kfree(txmsg);
1976 fail_put:
1977 	drm_dp_put_mst_branch_device(mstb);
1978 	return ret;
1979 }
1980 
1981 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
1982 {
1983 	struct drm_dp_sideband_msg_reply_body reply;
1984 
1985 	reply.reply_type = 1;
1986 	reply.req_type = req_type;
1987 	drm_dp_encode_sideband_reply(&reply, msg);
1988 	return 0;
1989 }
1990 
1991 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
1992 				    struct drm_dp_mst_branch *mstb,
1993 				    int req_type, int seqno, bool broadcast)
1994 {
1995 	struct drm_dp_sideband_msg_tx *txmsg;
1996 
1997 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1998 	if (!txmsg)
1999 		return -ENOMEM;
2000 
2001 	txmsg->dst = mstb;
2002 	txmsg->seqno = seqno;
2003 	drm_dp_encode_up_ack_reply(txmsg, req_type);
2004 
2005 	mutex_lock(&mgr->qlock);
2006 
2007 	process_single_up_tx_qlock(mgr, txmsg);
2008 
2009 	mutex_unlock(&mgr->qlock);
2010 
2011 	kfree(txmsg);
2012 	return 0;
2013 }
2014 
2015 static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
2016 				     int dp_link_count,
2017 				     int *out)
2018 {
2019 	switch (dp_link_bw) {
2020 	default:
2021 		DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
2022 			      dp_link_bw, dp_link_count);
2023 		return false;
2024 
2025 	case DP_LINK_BW_1_62:
2026 		*out = 3 * dp_link_count;
2027 		break;
2028 	case DP_LINK_BW_2_7:
2029 		*out = 5 * dp_link_count;
2030 		break;
2031 	case DP_LINK_BW_5_4:
2032 		*out = 10 * dp_link_count;
2033 		break;
2034 	}
2035 	return true;
2036 }
2037 
2038 /**
2039  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
2040  * @mgr: manager to set state for
2041  * @mst_state: true to enable MST on this connector - false to disable.
2042  *
2043  * This is called by the driver when it detects an MST capable device plugged
2044  * into a DP MST capable port, or when a DP MST capable device is unplugged.
2045  */
2046 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
2047 {
2048 	int ret = 0;
2049 	struct drm_dp_mst_branch *mstb = NULL;
2050 
2051 	mutex_lock(&mgr->lock);
2052 	if (mst_state == mgr->mst_state)
2053 		goto out_unlock;
2054 
2055 	mgr->mst_state = mst_state;
2056 	/* set the device into MST mode */
2057 	if (mst_state) {
2058 		WARN_ON(mgr->mst_primary);
2059 
2060 		/* get dpcd info */
2061 		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2062 		if (ret != DP_RECEIVER_CAP_SIZE) {
2063 			DRM_DEBUG_KMS("failed to read DPCD\n");
2064 			goto out_unlock;
2065 		}
2066 
2067 		if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
2068 					      mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
2069 					      &mgr->pbn_div)) {
2070 			ret = -EINVAL;
2071 			goto out_unlock;
2072 		}
2073 
2074 		mgr->total_pbn = 2560;
2075 		mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
2076 		mgr->avail_slots = mgr->total_slots;
2077 
2078 		/* add initial branch device at LCT 1 */
2079 		mstb = drm_dp_add_mst_branch_device(1, NULL);
2080 		if (mstb == NULL) {
2081 			ret = -ENOMEM;
2082 			goto out_unlock;
2083 		}
2084 		mstb->mgr = mgr;
2085 
2086 		/* give this the main reference */
2087 		mgr->mst_primary = mstb;
2088 		kref_get(&mgr->mst_primary->kref);
2089 
2090 		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2091 							 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2092 		if (ret < 0) {
2093 			goto out_unlock;
2094 		}
2095 
2096 		{
2097 			struct drm_dp_payload reset_pay;
2098 			reset_pay.start_slot = 0;
2099 			reset_pay.num_slots = 0x3f;
2100 			drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
2101 		}
2102 
2103 		queue_work(system_long_wq, &mgr->work);
2104 
2105 		ret = 0;
2106 	} else {
2107 		/* disable MST on the device */
2108 		mstb = mgr->mst_primary;
2109 		mgr->mst_primary = NULL;
2110 		/* this can fail if the device is gone */
2111 		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
2112 		ret = 0;
2113 		memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload));
2114 		mgr->payload_mask = 0;
2115 		set_bit(0, &mgr->payload_mask);
2116 		mgr->vcpi_mask = 0;
2117 	}
2118 
2119 out_unlock:
2120 	mutex_unlock(&mgr->lock);
2121 	if (mstb)
2122 		drm_dp_put_mst_branch_device(mstb);
2123 	return ret;
2124 
2125 }
2126 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
2127 
2128 /**
2129  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
2130  * @mgr: manager to suspend
2131  *
2132  * This function tells the MST device that we can't handle UP messages
2133  * anymore. This should stop it from sending any since we are suspended.
2134  */
2135 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
2136 {
2137 	mutex_lock(&mgr->lock);
2138 	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2139 			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
2140 	mutex_unlock(&mgr->lock);
2141 	flush_work(&mgr->work);
2142 	flush_work(&mgr->destroy_connector_work);
2143 }
2144 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
2145 
2146 /**
2147  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
2148  * @mgr: manager to resume
2149  *
2150  * This will fetch DPCD and see if the device is still there,
2151  * if it is, it will rewrite the MSTM control bits, and return.
2152  *
2153  * if the device fails this returns -1, and the driver should do
2154  * a full MST reprobe, in case we were undocked.
2155  */
2156 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
2157 {
2158 	int ret = 0;
2159 
2160 	mutex_lock(&mgr->lock);
2161 
2162 	if (mgr->mst_primary) {
2163 		int sret;
2164 		u8 guid[16];
2165 
2166 		sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2167 		if (sret != DP_RECEIVER_CAP_SIZE) {
2168 			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2169 			ret = -1;
2170 			goto out_unlock;
2171 		}
2172 
2173 		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2174 					 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2175 		if (ret < 0) {
2176 			DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
2177 			ret = -1;
2178 			goto out_unlock;
2179 		}
2180 
2181 		/* Some hubs forget their guids after they resume */
2182 		sret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
2183 		if (sret != 16) {
2184 			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2185 			ret = -1;
2186 			goto out_unlock;
2187 		}
2188 		drm_dp_check_mstb_guid(mgr->mst_primary, guid);
2189 
2190 		ret = 0;
2191 	} else
2192 		ret = -1;
2193 
2194 out_unlock:
2195 	mutex_unlock(&mgr->lock);
2196 	return ret;
2197 }
2198 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
2199 
2200 static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
2201 {
2202 	int len;
2203 	u8 replyblock[32];
2204 	int replylen, origlen __unused, curreply;
2205 	int ret;
2206 	struct drm_dp_sideband_msg_rx *msg;
2207 	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE;
2208 	msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
2209 
2210 	len = min(mgr->max_dpcd_transaction_bytes, 16);
2211 	ret = drm_dp_dpcd_read(mgr->aux, basereg,
2212 			       replyblock, len);
2213 	if (ret != len) {
2214 		DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
2215 		return false;
2216 	}
2217 	ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
2218 	if (!ret) {
2219 		DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
2220 		return false;
2221 	}
2222 	replylen = msg->curchunk_len + msg->curchunk_hdrlen;
2223 
2224 	origlen = replylen;
2225 	replylen -= len;
2226 	curreply = len;
2227 	while (replylen > 0) {
2228 		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
2229 		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
2230 				    replyblock, len);
2231 		if (ret != len) {
2232 			DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n",
2233 				      len, ret);
2234 			return false;
2235 		}
2236 
2237 		ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
2238 		if (!ret) {
2239 			DRM_DEBUG_KMS("failed to build sideband msg\n");
2240 			return false;
2241 		}
2242 
2243 		curreply += len;
2244 		replylen -= len;
2245 	}
2246 	return true;
2247 }
2248 
2249 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
2250 {
2251 	int ret = 0;
2252 
2253 	if (!drm_dp_get_one_sb_msg(mgr, false)) {
2254 		memset(&mgr->down_rep_recv, 0,
2255 		       sizeof(struct drm_dp_sideband_msg_rx));
2256 		return 0;
2257 	}
2258 
2259 	if (mgr->down_rep_recv.have_eomt) {
2260 		struct drm_dp_sideband_msg_tx *txmsg;
2261 		struct drm_dp_mst_branch *mstb;
2262 		int slot = -1;
2263 		mstb = drm_dp_get_mst_branch_device(mgr,
2264 						    mgr->down_rep_recv.initial_hdr.lct,
2265 						    mgr->down_rep_recv.initial_hdr.rad);
2266 
2267 		if (!mstb) {
2268 			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->down_rep_recv.initial_hdr.lct);
2269 			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2270 			return 0;
2271 		}
2272 
2273 		/* find the message */
2274 		slot = mgr->down_rep_recv.initial_hdr.seqno;
2275 		mutex_lock(&mgr->qlock);
2276 		txmsg = mstb->tx_slots[slot];
2277 		/* remove from slots */
2278 		mutex_unlock(&mgr->qlock);
2279 
2280 		if (!txmsg) {
2281 			DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
2282 			       mstb,
2283 			       mgr->down_rep_recv.initial_hdr.seqno,
2284 			       mgr->down_rep_recv.initial_hdr.lct,
2285 				      mgr->down_rep_recv.initial_hdr.rad[0],
2286 				      mgr->down_rep_recv.msg[0]);
2287 			drm_dp_put_mst_branch_device(mstb);
2288 			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2289 			return 0;
2290 		}
2291 
2292 		drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
2293 		if (txmsg->reply.reply_type == 1) {
2294 			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);
2295 		}
2296 
2297 		memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2298 		drm_dp_put_mst_branch_device(mstb);
2299 
2300 		mutex_lock(&mgr->qlock);
2301 		txmsg->state = DRM_DP_SIDEBAND_TX_RX;
2302 		mstb->tx_slots[slot] = NULL;
2303 #ifdef __NetBSD__
2304 		DRM_WAKEUP_ONE(&mstb->mgr->tx_waitq, &mstb->mgr->qlock);
2305 		mutex_unlock(&mgr->qlock);
2306 #else
2307 		mutex_unlock(&mgr->qlock);
2308 
2309 		wake_up(&mgr->tx_waitq);
2310 #endif
2311 	}
2312 	return ret;
2313 }
2314 
2315 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
2316 {
2317 	int ret = 0;
2318 
2319 	if (!drm_dp_get_one_sb_msg(mgr, true)) {
2320 		memset(&mgr->up_req_recv, 0,
2321 		       sizeof(struct drm_dp_sideband_msg_rx));
2322 		return 0;
2323 	}
2324 
2325 	if (mgr->up_req_recv.have_eomt) {
2326 		struct drm_dp_sideband_msg_req_body msg;
2327 		struct drm_dp_mst_branch *mstb = NULL;
2328 		bool seqno;
2329 
2330 		if (!mgr->up_req_recv.initial_hdr.broadcast) {
2331 			mstb = drm_dp_get_mst_branch_device(mgr,
2332 							    mgr->up_req_recv.initial_hdr.lct,
2333 							    mgr->up_req_recv.initial_hdr.rad);
2334 			if (!mstb) {
2335 				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2336 				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2337 				return 0;
2338 			}
2339 		}
2340 
2341 		seqno = mgr->up_req_recv.initial_hdr.seqno;
2342 		drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
2343 
2344 		if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
2345 			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2346 
2347 			if (!mstb)
2348 				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
2349 
2350 			if (!mstb) {
2351 				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2352 				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2353 				return 0;
2354 			}
2355 
2356 			drm_dp_update_port(mstb, &msg.u.conn_stat);
2357 
2358 			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);
2359 			(*mgr->cbs->hotplug)(mgr);
2360 
2361 		} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
2362 			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2363 			if (!mstb)
2364 				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
2365 
2366 			if (!mstb) {
2367 				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2368 				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2369 				return 0;
2370 			}
2371 
2372 			DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
2373 		}
2374 
2375 		if (mstb)
2376 			drm_dp_put_mst_branch_device(mstb);
2377 
2378 		memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2379 	}
2380 	return ret;
2381 }
2382 
2383 /**
2384  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
2385  * @mgr: manager to notify irq for.
2386  * @esi: 4 bytes from SINK_COUNT_ESI
2387  * @handled: whether the hpd interrupt was consumed or not
2388  *
2389  * This should be called from the driver when it detects a short IRQ,
2390  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
2391  * topology manager will process the sideband messages received as a result
2392  * of this.
2393  */
2394 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
2395 {
2396 	int ret = 0;
2397 	int sc;
2398 	*handled = false;
2399 	sc = esi[0] & 0x3f;
2400 
2401 	if (sc != mgr->sink_count) {
2402 		mgr->sink_count = sc;
2403 		*handled = true;
2404 	}
2405 
2406 	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
2407 		ret = drm_dp_mst_handle_down_rep(mgr);
2408 		*handled = true;
2409 	}
2410 
2411 	if (esi[1] & DP_UP_REQ_MSG_RDY) {
2412 		ret |= drm_dp_mst_handle_up_req(mgr);
2413 		*handled = true;
2414 	}
2415 
2416 	drm_dp_mst_kick_tx(mgr);
2417 	return ret;
2418 }
2419 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
2420 
2421 /**
2422  * drm_dp_mst_detect_port() - get connection status for an MST port
2423  * @mgr: manager for this port
2424  * @port: unverified pointer to a port
2425  *
2426  * This returns the current connection state for a port. It validates the
2427  * port pointer still exists so the caller doesn't require a reference
2428  */
2429 enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector,
2430 						 struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2431 {
2432 	enum drm_connector_status status = connector_status_disconnected;
2433 
2434 	/* we need to search for the port in the mgr in case its gone */
2435 	port = drm_dp_get_validated_port_ref(mgr, port);
2436 	if (!port)
2437 		return connector_status_disconnected;
2438 
2439 	if (!port->ddps)
2440 		goto out;
2441 
2442 	switch (port->pdt) {
2443 	case DP_PEER_DEVICE_NONE:
2444 	case DP_PEER_DEVICE_MST_BRANCHING:
2445 		break;
2446 
2447 	case DP_PEER_DEVICE_SST_SINK:
2448 		status = connector_status_connected;
2449 		/* for logical ports - cache the EDID */
2450 		if (port->port_num >= 8 && !port->cached_edid) {
2451 			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
2452 		}
2453 		break;
2454 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2455 		if (port->ldps)
2456 			status = connector_status_connected;
2457 		break;
2458 	}
2459 out:
2460 	drm_dp_put_port(port);
2461 	return status;
2462 }
2463 EXPORT_SYMBOL(drm_dp_mst_detect_port);
2464 
2465 /**
2466  * drm_dp_mst_get_edid() - get EDID for an MST port
2467  * @connector: toplevel connector to get EDID for
2468  * @mgr: manager for this port
2469  * @port: unverified pointer to a port.
2470  *
2471  * This returns an EDID for the port connected to a connector,
2472  * It validates the pointer still exists so the caller doesn't require a
2473  * reference.
2474  */
2475 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2476 {
2477 	struct edid *edid = NULL;
2478 
2479 	/* we need to search for the port in the mgr in case its gone */
2480 	port = drm_dp_get_validated_port_ref(mgr, port);
2481 	if (!port)
2482 		return NULL;
2483 
2484 	if (port->cached_edid)
2485 		edid = drm_edid_duplicate(port->cached_edid);
2486 	else {
2487 		edid = drm_get_edid(connector, &port->aux.ddc);
2488 		drm_mode_connector_set_tile_property(connector);
2489 	}
2490 	drm_dp_put_port(port);
2491 	return edid;
2492 }
2493 EXPORT_SYMBOL(drm_dp_mst_get_edid);
2494 
2495 /**
2496  * drm_dp_find_vcpi_slots() - find slots for this PBN value
2497  * @mgr: manager to use
2498  * @pbn: payload bandwidth to convert into slots.
2499  */
2500 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
2501 			   int pbn)
2502 {
2503 	int num_slots;
2504 
2505 	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2506 
2507 	if (num_slots > mgr->avail_slots)
2508 		return -ENOSPC;
2509 	return num_slots;
2510 }
2511 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
2512 
2513 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
2514 			    struct drm_dp_vcpi *vcpi, int pbn)
2515 {
2516 	int num_slots;
2517 	int ret;
2518 
2519 	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2520 
2521 	if (num_slots > mgr->avail_slots)
2522 		return -ENOSPC;
2523 
2524 	vcpi->pbn = pbn;
2525 	vcpi->aligned_pbn = num_slots * mgr->pbn_div;
2526 	vcpi->num_slots = num_slots;
2527 
2528 	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
2529 	if (ret < 0)
2530 		return ret;
2531 	return 0;
2532 }
2533 
2534 /**
2535  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
2536  * @mgr: manager for this port
2537  * @port: port to allocate a virtual channel for.
2538  * @pbn: payload bandwidth number to request
2539  * @slots: returned number of slots for this PBN.
2540  */
2541 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int *slots)
2542 {
2543 	int ret;
2544 
2545 	port = drm_dp_get_validated_port_ref(mgr, port);
2546 	if (!port)
2547 		return false;
2548 
2549 	if (port->vcpi.vcpi > 0) {
2550 		DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn);
2551 		if (pbn == port->vcpi.pbn) {
2552 			*slots = port->vcpi.num_slots;
2553 			drm_dp_put_port(port);
2554 			return true;
2555 		}
2556 	}
2557 
2558 	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn);
2559 	if (ret) {
2560 		DRM_DEBUG_KMS("failed to init vcpi %d %d %d\n", DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->avail_slots, ret);
2561 		goto out;
2562 	}
2563 	DRM_DEBUG_KMS("initing vcpi for %d %d\n", pbn, port->vcpi.num_slots);
2564 	*slots = port->vcpi.num_slots;
2565 
2566 	drm_dp_put_port(port);
2567 	return true;
2568 out:
2569 	return false;
2570 }
2571 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
2572 
2573 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2574 {
2575 	int slots = 0;
2576 	port = drm_dp_get_validated_port_ref(mgr, port);
2577 	if (!port)
2578 		return slots;
2579 
2580 	slots = port->vcpi.num_slots;
2581 	drm_dp_put_port(port);
2582 	return slots;
2583 }
2584 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
2585 
2586 /**
2587  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
2588  * @mgr: manager for this port
2589  * @port: unverified pointer to a port.
2590  *
2591  * This just resets the number of slots for the ports VCPI for later programming.
2592  */
2593 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2594 {
2595 	port = drm_dp_get_validated_port_ref(mgr, port);
2596 	if (!port)
2597 		return;
2598 	port->vcpi.num_slots = 0;
2599 	drm_dp_put_port(port);
2600 }
2601 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
2602 
2603 /**
2604  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
2605  * @mgr: manager for this port
2606  * @port: unverified port to deallocate vcpi for
2607  */
2608 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2609 {
2610 	port = drm_dp_get_validated_port_ref(mgr, port);
2611 	if (!port)
2612 		return;
2613 
2614 	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2615 	port->vcpi.num_slots = 0;
2616 	port->vcpi.pbn = 0;
2617 	port->vcpi.aligned_pbn = 0;
2618 	port->vcpi.vcpi = 0;
2619 	drm_dp_put_port(port);
2620 }
2621 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
2622 
2623 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
2624 				     int id, struct drm_dp_payload *payload)
2625 {
2626 	u8 payload_alloc[3], status;
2627 	int ret;
2628 	int retries = 0;
2629 
2630 	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
2631 			   DP_PAYLOAD_TABLE_UPDATED);
2632 
2633 	payload_alloc[0] = id;
2634 	payload_alloc[1] = payload->start_slot;
2635 	payload_alloc[2] = payload->num_slots;
2636 
2637 	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
2638 	if (ret != 3) {
2639 		DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
2640 		goto fail;
2641 	}
2642 
2643 retry:
2644 	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2645 	if (ret < 0) {
2646 		DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2647 		goto fail;
2648 	}
2649 
2650 	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
2651 		retries++;
2652 		if (retries < 20) {
2653 			usleep_range(10000, 20000);
2654 			goto retry;
2655 		}
2656 		DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
2657 		ret = -EINVAL;
2658 		goto fail;
2659 	}
2660 	ret = 0;
2661 fail:
2662 	return ret;
2663 }
2664 
2665 
2666 /**
2667  * drm_dp_check_act_status() - Check ACT handled status.
2668  * @mgr: manager to use
2669  *
2670  * Check the payload status bits in the DPCD for ACT handled completion.
2671  */
2672 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
2673 {
2674 	u8 status;
2675 	int ret;
2676 	int count = 0;
2677 
2678 	do {
2679 		ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2680 
2681 		if (ret < 0) {
2682 			DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2683 			goto fail;
2684 		}
2685 
2686 		if (status & DP_PAYLOAD_ACT_HANDLED)
2687 			break;
2688 		count++;
2689 		udelay(100);
2690 
2691 	} while (count < 30);
2692 
2693 	if (!(status & DP_PAYLOAD_ACT_HANDLED)) {
2694 		DRM_DEBUG_KMS("failed to get ACT bit %d after %d retries\n", status, count);
2695 		ret = -EINVAL;
2696 		goto fail;
2697 	}
2698 	return 0;
2699 fail:
2700 	return ret;
2701 }
2702 EXPORT_SYMBOL(drm_dp_check_act_status);
2703 
2704 /**
2705  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
2706  * @clock: dot clock for the mode
2707  * @bpp: bpp for the mode.
2708  *
2709  * This uses the formula in the spec to calculate the PBN value for a mode.
2710  */
2711 int drm_dp_calc_pbn_mode(int clock, int bpp)
2712 {
2713 	u64 kbps;
2714 	s64 peak_kbps;
2715 	u32 numerator;
2716 	u32 denominator;
2717 
2718 	kbps = clock * bpp;
2719 
2720 	/*
2721 	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
2722 	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
2723 	 * common multiplier to render an integer PBN for all link rate/lane
2724 	 * counts combinations
2725 	 * calculate
2726 	 * peak_kbps *= (1006/1000)
2727 	 * peak_kbps *= (64/54)
2728 	 * peak_kbps *= 8    convert to bytes
2729 	 */
2730 
2731 	numerator = 64 * 1006;
2732 	denominator = 54 * 8 * 1000 * 1000;
2733 
2734 	kbps *= numerator;
2735 	peak_kbps = drm_fixp_from_fraction(kbps, denominator);
2736 
2737 	return drm_fixp2int_ceil(peak_kbps);
2738 }
2739 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
2740 
2741 static int test_calc_pbn_mode(void)
2742 {
2743 	int ret;
2744 	ret = drm_dp_calc_pbn_mode(154000, 30);
2745 	if (ret != 689) {
2746 		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2747 				154000, 30, 689, ret);
2748 		return -EINVAL;
2749 	}
2750 	ret = drm_dp_calc_pbn_mode(234000, 30);
2751 	if (ret != 1047) {
2752 		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2753 				234000, 30, 1047, ret);
2754 		return -EINVAL;
2755 	}
2756 	ret = drm_dp_calc_pbn_mode(297000, 24);
2757 	if (ret != 1063) {
2758 		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2759 				297000, 24, 1063, ret);
2760 		return -EINVAL;
2761 	}
2762 	return 0;
2763 }
2764 
2765 /* we want to kick the TX after we've ack the up/down IRQs. */
2766 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
2767 {
2768 	queue_work(system_long_wq, &mgr->tx_work);
2769 }
2770 
2771 #if IS_ENABLED(CONFIG_DEBUG_FS)
2772 static void drm_dp_mst_dump_mstb(struct seq_file *m,
2773 				 struct drm_dp_mst_branch *mstb)
2774 {
2775 	struct drm_dp_mst_port *port;
2776 	int tabs = mstb->lct;
2777 	char prefix[10];
2778 	int i;
2779 
2780 	for (i = 0; i < tabs; i++)
2781 		prefix[i] = '\t';
2782 	prefix[i] = '\0';
2783 
2784 	seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
2785 	list_for_each_entry(port, &mstb->ports, next) {
2786 		seq_printf(m, "%sport: %d: ddps: %d ldps: %d, %p, conn: %p\n", prefix, port->port_num, port->ddps, port->ldps, port, port->connector);
2787 		if (port->mstb)
2788 			drm_dp_mst_dump_mstb(m, port->mstb);
2789 	}
2790 }
2791 
2792 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
2793 				  char *buf)
2794 {
2795 	int ret;
2796 	int i;
2797 	for (i = 0; i < 4; i++) {
2798 		ret = drm_dp_dpcd_read(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS + (i * 16), &buf[i * 16], 16);
2799 		if (ret != 16)
2800 			break;
2801 	}
2802 	if (i == 4)
2803 		return true;
2804 	return false;
2805 }
2806 
2807 /**
2808  * drm_dp_mst_dump_topology(): dump topology to seq file.
2809  * @m: seq_file to dump output to
2810  * @mgr: manager to dump current topology for.
2811  *
2812  * helper to dump MST topology to a seq file for debugfs.
2813  */
2814 void drm_dp_mst_dump_topology(struct seq_file *m,
2815 			      struct drm_dp_mst_topology_mgr *mgr)
2816 {
2817 	int i;
2818 	struct drm_dp_mst_port *port;
2819 	mutex_lock(&mgr->lock);
2820 	if (mgr->mst_primary)
2821 		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
2822 
2823 	/* dump VCPIs */
2824 	mutex_unlock(&mgr->lock);
2825 
2826 	mutex_lock(&mgr->payload_lock);
2827 	seq_printf(m, "vcpi: %lx %lx\n", mgr->payload_mask, mgr->vcpi_mask);
2828 
2829 	for (i = 0; i < mgr->max_payloads; i++) {
2830 		if (mgr->proposed_vcpis[i]) {
2831 			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
2832 			seq_printf(m, "vcpi %d: %d %d %d\n", i, port->port_num, port->vcpi.vcpi, port->vcpi.num_slots);
2833 		} else
2834 			seq_printf(m, "vcpi %d:unsed\n", i);
2835 	}
2836 	for (i = 0; i < mgr->max_payloads; i++) {
2837 		seq_printf(m, "payload %d: %d, %d, %d\n",
2838 			   i,
2839 			   mgr->payloads[i].payload_state,
2840 			   mgr->payloads[i].start_slot,
2841 			   mgr->payloads[i].num_slots);
2842 
2843 
2844 	}
2845 	mutex_unlock(&mgr->payload_lock);
2846 
2847 	mutex_lock(&mgr->lock);
2848 	if (mgr->mst_primary) {
2849 		u8 buf[64];
2850 		bool bret;
2851 		int ret;
2852 		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
2853 		seq_printf(m, "dpcd: ");
2854 		for (i = 0; i < DP_RECEIVER_CAP_SIZE; i++)
2855 			seq_printf(m, "%02x ", buf[i]);
2856 		seq_printf(m, "\n");
2857 		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
2858 		seq_printf(m, "faux/mst: ");
2859 		for (i = 0; i < 2; i++)
2860 			seq_printf(m, "%02x ", buf[i]);
2861 		seq_printf(m, "\n");
2862 		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
2863 		seq_printf(m, "mst ctrl: ");
2864 		for (i = 0; i < 1; i++)
2865 			seq_printf(m, "%02x ", buf[i]);
2866 		seq_printf(m, "\n");
2867 
2868 		/* dump the standard OUI branch header */
2869 		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
2870 		seq_printf(m, "branch oui: ");
2871 		for (i = 0; i < 0x3; i++)
2872 			seq_printf(m, "%02x", buf[i]);
2873 		seq_printf(m, " devid: ");
2874 		for (i = 0x3; i < 0x8; i++)
2875 			seq_printf(m, "%c", buf[i]);
2876 		seq_printf(m, " revision: hw: %x.%x sw: %x.%x", buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
2877 		seq_printf(m, "\n");
2878 		bret = dump_dp_payload_table(mgr, buf);
2879 		if (bret == true) {
2880 			seq_printf(m, "payload table: ");
2881 			for (i = 0; i < 63; i++)
2882 				seq_printf(m, "%02x ", buf[i]);
2883 			seq_printf(m, "\n");
2884 		}
2885 
2886 	}
2887 
2888 	mutex_unlock(&mgr->lock);
2889 
2890 }
2891 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
2892 #endif	/* IS_ENABLED(CONFIG_DEBUG_FS) */
2893 
2894 static void drm_dp_tx_work(struct work_struct *work)
2895 {
2896 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
2897 
2898 	mutex_lock(&mgr->qlock);
2899 	if (mgr->tx_down_in_progress)
2900 		process_single_down_tx_qlock(mgr);
2901 	mutex_unlock(&mgr->qlock);
2902 }
2903 
2904 static void drm_dp_free_mst_port(struct kref *kref)
2905 {
2906 	struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
2907 	kref_put(&port->parent->kref, drm_dp_free_mst_branch_device);
2908 	kfree(port);
2909 }
2910 
2911 static void drm_dp_destroy_connector_work(struct work_struct *work)
2912 {
2913 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
2914 	struct drm_dp_mst_port *port;
2915 	bool send_hotplug = false;
2916 	/*
2917 	 * Not a regular list traverse as we have to drop the destroy
2918 	 * connector lock before destroying the connector, to avoid AB->BA
2919 	 * ordering between this lock and the config mutex.
2920 	 */
2921 	for (;;) {
2922 		mutex_lock(&mgr->destroy_connector_lock);
2923 		port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next);
2924 		if (!port) {
2925 			mutex_unlock(&mgr->destroy_connector_lock);
2926 			break;
2927 		}
2928 		list_del(&port->next);
2929 		mutex_unlock(&mgr->destroy_connector_lock);
2930 
2931 		kref_init(&port->kref);
2932 		INIT_LIST_HEAD(&port->next);
2933 
2934 		mgr->cbs->destroy_connector(mgr, port->connector);
2935 
2936 		drm_dp_port_teardown_pdt(port, port->pdt);
2937 		port->pdt = DP_PEER_DEVICE_NONE;
2938 
2939 		if (!port->input && port->vcpi.vcpi > 0) {
2940 			drm_dp_mst_reset_vcpi_slots(mgr, port);
2941 			drm_dp_update_payload_part1(mgr);
2942 			drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2943 		}
2944 
2945 		kref_put(&port->kref, drm_dp_free_mst_port);
2946 		send_hotplug = true;
2947 	}
2948 	if (send_hotplug)
2949 		(*mgr->cbs->hotplug)(mgr);
2950 }
2951 
2952 /**
2953  * drm_dp_mst_topology_mgr_init - initialise a topology manager
2954  * @mgr: manager struct to initialise
2955  * @dev: device providing this structure - for i2c addition.
2956  * @aux: DP helper aux channel to talk to this device
2957  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
2958  * @max_payloads: maximum number of payloads this GPU can source
2959  * @conn_base_id: the connector object ID the MST device is connected to.
2960  *
2961  * Return 0 for success, or negative error code on failure
2962  */
2963 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
2964 				 struct device *dev, struct drm_dp_aux *aux,
2965 				 int max_dpcd_transaction_bytes,
2966 				 int max_payloads, int conn_base_id)
2967 {
2968 	mutex_init(&mgr->lock);
2969 	mutex_init(&mgr->qlock);
2970 	mutex_init(&mgr->payload_lock);
2971 	mutex_init(&mgr->destroy_connector_lock);
2972 	INIT_LIST_HEAD(&mgr->tx_msg_downq);
2973 	INIT_LIST_HEAD(&mgr->destroy_connector_list);
2974 	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
2975 	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
2976 	INIT_WORK(&mgr->destroy_connector_work, drm_dp_destroy_connector_work);
2977 #ifdef __NetBSD__
2978 	DRM_INIT_WAITQUEUE(&mgr->tx_waitq, "dpmstwait");
2979 #else
2980 	init_waitqueue_head(&mgr->tx_waitq);
2981 #endif
2982 	mgr->dev = dev;
2983 	mgr->aux = aux;
2984 	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
2985 	mgr->max_payloads = max_payloads;
2986 	mgr->conn_base_id = conn_base_id;
2987 	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
2988 	if (!mgr->payloads)
2989 		return -ENOMEM;
2990 	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
2991 	if (!mgr->proposed_vcpis)
2992 		return -ENOMEM;
2993 	set_bit(0, &mgr->payload_mask);
2994 	test_calc_pbn_mode();
2995 	return 0;
2996 }
2997 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
2998 
2999 /**
3000  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
3001  * @mgr: manager to destroy
3002  */
3003 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
3004 {
3005 	flush_work(&mgr->work);
3006 	flush_work(&mgr->destroy_connector_work);
3007 	mutex_lock(&mgr->payload_lock);
3008 	kfree(mgr->payloads);
3009 	mgr->payloads = NULL;
3010 	kfree(mgr->proposed_vcpis);
3011 	mgr->proposed_vcpis = NULL;
3012 	mutex_unlock(&mgr->payload_lock);
3013 	mgr->dev = NULL;
3014 	mgr->aux = NULL;
3015 #ifdef __NetBSD__
3016 	DRM_DESTROY_WAITQUEUE(&mgr->tx_waitq);
3017 #endif
3018 	mutex_destroy(&mgr->destroy_connector_lock);
3019 	mutex_destroy(&mgr->payload_lock);
3020 	mutex_destroy(&mgr->qlock);
3021 	mutex_destroy(&mgr->lock);
3022 }
3023 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
3024 
3025 /* I2C device */
3026 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
3027 			       int num)
3028 {
3029 	struct drm_dp_aux *aux = adapter->algo_data;
3030 	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
3031 	struct drm_dp_mst_branch *mstb;
3032 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
3033 	unsigned int i;
3034 	bool reading = false;
3035 	struct drm_dp_sideband_msg_req_body msg;
3036 	struct drm_dp_sideband_msg_tx *txmsg = NULL;
3037 	int ret;
3038 
3039 	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
3040 	if (!mstb)
3041 		return -EREMOTEIO;
3042 
3043 	/* construct i2c msg */
3044 	/* see if last msg is a read */
3045 	if (msgs[num - 1].flags & I2C_M_RD)
3046 		reading = true;
3047 
3048 	if (!reading || (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)) {
3049 		DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
3050 		ret = -EIO;
3051 		goto out;
3052 	}
3053 
3054 	memset(&msg, 0, sizeof(msg));
3055 	msg.req_type = DP_REMOTE_I2C_READ;
3056 	msg.u.i2c_read.num_transactions = num - 1;
3057 	msg.u.i2c_read.port_number = port->port_num;
3058 	for (i = 0; i < num - 1; i++) {
3059 		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
3060 		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
3061 		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
3062 	}
3063 	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
3064 	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
3065 
3066 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3067 	if (!txmsg) {
3068 		ret = -ENOMEM;
3069 		goto out;
3070 	}
3071 
3072 	txmsg->dst = mstb;
3073 	drm_dp_encode_sideband_req(&msg, txmsg);
3074 
3075 	drm_dp_queue_down_tx(mgr, txmsg);
3076 
3077 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3078 	if (ret > 0) {
3079 
3080 		if (txmsg->reply.reply_type == 1) { /* got a NAK back */
3081 			ret = -EREMOTEIO;
3082 			goto out;
3083 		}
3084 		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
3085 			ret = -EIO;
3086 			goto out;
3087 		}
3088 		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
3089 		ret = num;
3090 	}
3091 out:
3092 	kfree(txmsg);
3093 	drm_dp_put_mst_branch_device(mstb);
3094 	return ret;
3095 }
3096 
3097 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
3098 {
3099 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
3100 	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
3101 	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
3102 	       I2C_FUNC_10BIT_ADDR;
3103 }
3104 
3105 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
3106 	.functionality = drm_dp_mst_i2c_functionality,
3107 	.master_xfer = drm_dp_mst_i2c_xfer,
3108 };
3109 
3110 /**
3111  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
3112  * @aux: DisplayPort AUX channel
3113  *
3114  * Returns 0 on success or a negative error code on failure.
3115  */
3116 static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
3117 {
3118 	aux->ddc.algo = &drm_dp_mst_i2c_algo;
3119 	aux->ddc.algo_data = aux;
3120 	aux->ddc.retries = 3;
3121 
3122 	aux->ddc.class = I2C_CLASS_DDC;
3123 	aux->ddc.owner = THIS_MODULE;
3124 	aux->ddc.dev.parent = aux->dev;
3125 #ifndef __NetBSD__		/* XXX of? */
3126 	aux->ddc.dev.of_node = aux->dev->of_node;
3127 #endif
3128 
3129 	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
3130 		sizeof(aux->ddc.name));
3131 
3132 	return i2c_add_adapter(&aux->ddc);
3133 }
3134 
3135 /**
3136  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
3137  * @aux: DisplayPort AUX channel
3138  */
3139 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
3140 {
3141 	i2c_del_adapter(&aux->ddc);
3142 }
3143