1 /* $NetBSD: zs_kgdb.c,v 1.15 2023/10/24 19:05:07 andvar Exp $ */
2
3 /*-
4 * Copyright (c) 1996 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Gordon W. Ross.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * Hooks for kgdb when attached via the z8530 driver
34 *
35 * To use this, build a kernel with: option KGDB, and
36 * boot that kernel with "-d". (The kernel will call
37 * zs_kgdb_init, kgdb_connect.) When the console prints
38 * "kgdb waiting..." you run "gdb -k kernel" and do:
39 * (gdb) set remotebaud 19200
40 * (gdb) target remote /dev/ttyb
41 */
42
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: zs_kgdb.c,v 1.15 2023/10/24 19:05:07 andvar Exp $");
45
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/proc.h>
49 #include <sys/device.h>
50 #include <sys/conf.h>
51 #include <sys/ioctl.h>
52 #include <sys/kernel.h>
53 #include <sys/syslog.h>
54 #include <sys/kgdb.h>
55
56 #include <dev/ofw/openfirm.h>
57 #include <dev/ic/z8530reg.h>
58 #include <machine/z8530var.h>
59
60 static void zs_setparam(struct zs_chanstate *, int, int);
61 static void zskgdb(struct zs_chanstate *);
62
63 struct zsops zsops_kgdb;
64
65 static u_char zs_kgdb_regs[16] = {
66 0, /* 0: CMD (reset, etc.) */
67 0, /* 1: ~(ZSWR1_RIE | ZSWR1_TIE | ZSWR1_SIE) */
68 0, /* IVECT */
69 ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
70 ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
71 ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
72 0, /* 6: TXSYNC/SYNCLO */
73 0, /* 7: RXSYNC/SYNCHI */
74 0, /* 8: alias for data port */
75 ZSWR9_MASTER_IE,
76 0, /*10: Misc. TX/RX control bits */
77 ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
78 ((PCLK/32)/38400)-2, /*12: BAUDLO (default=38400) */
79 0, /*13: BAUDHI (default=38400) */
80 ZSWR14_BAUD_ENA,
81 ZSWR15_BREAK_IE,
82 };
83
84 /*
85 * This replaces "zs_reset()" in the sparc driver.
86 */
87 static void
zs_setparam(struct zs_chanstate * cs,int iena,int rate)88 zs_setparam(struct zs_chanstate *cs, int iena, int rate)
89 {
90 int s, tconst;
91
92 memcpy(cs->cs_preg, zs_kgdb_regs, 16);
93
94 if (iena) {
95 cs->cs_preg[1] = ZSWR1_RIE | ZSWR1_SIE;
96 }
97
98 /* Initialize the speed, etc. */
99 tconst = BPS_TO_TCONST(cs->cs_brg_clk, rate);
100 cs->cs_preg[5] |= ZSWR5_DTR | ZSWR5_RTS;
101 cs->cs_preg[12] = tconst;
102 cs->cs_preg[13] = tconst >> 8;
103
104 s = splhigh();
105 zs_loadchannelregs(cs);
106 splx(s);
107 }
108
109 #ifndef KGDB_DEVNAME
110 #define KGDB_DEVNAME "scca"
111 #endif
112 const char *zs_kgdb_devname = KGDB_DEVNAME;
113 /*
114 * Set up for kgdb; called at boot time before configuration.
115 * KGDB interrupts will be enabled later when zs0 is configured.
116 * Called after cninit(), so printf() etc. works.
117 */
118 void
zs_kgdb_init(void)119 zs_kgdb_init(void)
120 {
121 extern const struct cdevsw zstty_cdevsw;
122 struct zs_chanstate cs;
123 volatile struct zschan *zc;
124 int escc, escc_ch, obio, zs_offset;
125 int channel = 0;
126 u_int32_t reg[5];
127 char name[16];
128
129 if ((escc_ch = OF_finddevice(zs_kgdb_devname)) == -1)
130 return;
131
132 memset(name, 0, sizeof(name));
133 if (OF_getprop(escc_ch, "device_type", name, sizeof(name)) == -1)
134 return;
135
136 if (strcmp(name, "serial") != 0)
137 return;
138
139 memset(name, 0, sizeof(name));
140 if (OF_getprop(escc_ch, "name", name, sizeof(name)) == -1)
141 return;
142
143 if (strcmp(name, "ch-b") == 0)
144 channel = 1;
145
146 if (OF_getprop(escc_ch, "reg", reg, sizeof(reg)) < 4)
147 return;
148 zs_offset = reg[0];
149
150 escc = OF_parent(escc_ch);
151 obio = OF_parent(escc);
152
153 if (OF_getprop(obio, "assigned-addresses", reg, sizeof(reg)) < 12)
154 return;
155 zc = (struct zschan *)(reg[2] + zs_offset);
156
157 kgdb_dev = makedev(cdevsw_lookup_major(&zstty_cdevsw), channel);
158
159 printf("zs_kgdb_init: attaching tty%02d at %d baud\n",
160 channel, kgdb_rate);
161
162 /* Setup temporary chanstate. */
163 memset((void *)&cs, 0, sizeof(cs));
164 cs.cs_channel = channel;
165 cs.cs_brg_clk = PCLK / 16;
166 cs.cs_reg_csr = &zc->zc_csr;
167 cs.cs_reg_data = &zc->zc_data;
168
169 /* Now set parameters. (interrupts disabled) */
170 zs_setparam(&cs, 0, kgdb_rate);
171
172 /* Store the getc/putc functions and arg. */
173 kgdb_attach(zs_getc, zs_putc, __UNVOLATILE(zc));
174 }
175
176 /*
177 * This is a "hook" called by zstty_attach to allow the tty
178 * to be "taken over" for exclusive use by kgdb.
179 * Return non-zero if this is the kgdb port.
180 *
181 * Set the speed to kgdb_rate, CS8, etc.
182 */
183 int
zs_check_kgdb(struct zs_chanstate * cs,int dev)184 zs_check_kgdb(struct zs_chanstate *cs, int dev)
185 {
186
187 if (dev != kgdb_dev)
188 return (0);
189
190 /*
191 * Yes, this is port in use by kgdb.
192 */
193 cs->cs_private = NULL;
194 cs->cs_ops = &zsops_kgdb;
195
196 /* Now set parameters. (interrupts enabled) */
197 zs_setparam(cs, 1, kgdb_rate);
198
199 return (1);
200 }
201
202 /*
203 * KGDB framing character received: enter kernel debugger. This probably
204 * should time out after a few seconds to avoid hanging on spurious input.
205 */
206 static void
zskgdb(struct zs_chanstate * cs)207 zskgdb(struct zs_chanstate *cs)
208 {
209 int unit = minor(kgdb_dev);
210
211 printf("zstty%d: kgdb interrupt\n", unit);
212 /* This will trap into the debugger. */
213 kgdb_connect(1);
214 }
215
216
217 /****************************************************************
218 * Interface to the lower layer (zscc)
219 ****************************************************************/
220
221 static void zs_kgdb_rxint(struct zs_chanstate *);
222 static void zs_kgdb_stint(struct zs_chanstate *, int);
223 static void zs_kgdb_txint(struct zs_chanstate *);
224 static void zs_kgdb_softint(struct zs_chanstate *);
225
226 int kgdb_input_lost;
227
228 static void
zs_kgdb_rxint(struct zs_chanstate * cs)229 zs_kgdb_rxint(struct zs_chanstate *cs)
230 {
231 register u_char c, rr1;
232
233 /*
234 * First read the status, because reading the received char
235 * destroys the status of this char.
236 */
237 rr1 = zs_read_reg(cs, 1);
238 c = zs_read_data(cs);
239
240 if (rr1 & (ZSRR1_FE | ZSRR1_DO | ZSRR1_PE)) {
241 /* Clear the receive error. */
242 zs_write_csr(cs, ZSWR0_RESET_ERRORS);
243 }
244
245 if (c == KGDB_START) {
246 zskgdb(cs);
247 } else {
248 kgdb_input_lost++;
249 }
250 }
251
252 static void
zs_kgdb_txint(register struct zs_chanstate * cs)253 zs_kgdb_txint(register struct zs_chanstate *cs)
254 {
255 zs_write_csr(cs, ZSWR0_RESET_TXINT);
256 }
257
258 static void
zs_kgdb_stint(register struct zs_chanstate * cs,int force)259 zs_kgdb_stint(register struct zs_chanstate *cs, int force)
260 {
261 register int rr0;
262
263 rr0 = zs_read_csr(cs);
264 zs_write_csr(cs, ZSWR0_RESET_STATUS);
265
266 /*
267 * Check here for console break, so that we can abort
268 * even when interrupts are locking up the machine.
269 */
270 if (rr0 & ZSRR0_BREAK) {
271 zskgdb(cs);
272 }
273 }
274
275 static void
zs_kgdb_softint(struct zs_chanstate * cs)276 zs_kgdb_softint(struct zs_chanstate *cs)
277 {
278 printf("zs_kgdb_softint?\n");
279 }
280
281 struct zsops zsops_kgdb = {
282 zs_kgdb_rxint, /* receive char available */
283 zs_kgdb_stint, /* external/status */
284 zs_kgdb_txint, /* xmit buffer empty */
285 zs_kgdb_softint, /* process software interrupt */
286 };
287