1 /* $NetBSD: zs_kgdb.c,v 1.13 2023/10/20 11:38:25 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 1.13 2023/10/20 11:38:25 andvar Exp $");
45
46 #include "opt_kgdb.h"
47
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/proc.h>
51 #include <sys/device.h>
52 #include <sys/conf.h>
53 #include <sys/ioctl.h>
54 #include <sys/kernel.h>
55 #include <sys/syslog.h>
56 #include <sys/kgdb.h>
57
58 #include <machine/cpu.h>
59
60 #include <dev/ic/z8530reg.h>
61 #include <machine/z8530var.h>
62 #include <next68k/dev/zs_cons.h>
63
64 /*
65 * The NeXT provides a 3.686400 MHz clock to the ZS chips.
66 */
67 #define PCLK (9600 * 384) /* PCLK pin input clock rate */
68
69 /* The layout of this is hardware-dependent (padding, order). */
70 struct zschan {
71 volatile uint8_t zc_csr; /* ctrl,status, and indirect access */
72 uint8_t zc_xxx0;
73 volatile uint8_t zc_data; /* data */
74 uint8_t zc_xxx1;
75 };
76
77 static void zs_setparam(struct zs_chanstate *, int, int);
78 struct zsops zsops_kgdb;
79
80 static uint8_t zs_kgdb_regs[16] = {
81 0, /* 0: CMD (reset, etc.) */
82 0, /* 1: No interrupts yet. */
83 0x18 + NEXT_I_IPL(NEXT_I_SCC), /* 2: IVECT */
84 ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
85 ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
86 ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
87 0, /* 6: TXSYNC/SYNCLO */
88 0, /* 7: RXSYNC/SYNCHI */
89 0, /* 8: alias for data port */
90 ZSWR9_MASTER_IE,
91 0, /*10: Misc. TX/RX control bits */
92 ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
93 ((PCLK/32)/9600)-2, /*12: BAUDLO (default=9600) */
94 0, /*13: BAUDHI (default=9600) */
95 ZSWR14_BAUD_ENA | ZSWR14_BAUD_FROM_PCLK,
96 ZSWR15_BREAK_IE,
97 };
98
99 /*
100 * This replaces "zs_reset()" in the sparc driver.
101 */
102 static void
zs_setparam(struct zs_chanstate * cs,int iena,int rate)103 zs_setparam(struct zs_chanstate *cs, int iena, int rate)
104 {
105 int s, tconst;
106
107 memcpy(cs->cs_preg, zs_kgdb_regs, 16);
108
109 if (iena) {
110 cs->cs_preg[1] = ZSWR1_RIE | ZSWR1_SIE;
111 }
112
113 /* Initialize the speed, etc. */
114 tconst = BPS_TO_TCONST(cs->cs_brg_clk, rate);
115 cs->cs_preg[5] |= ZSWR5_DTR | ZSWR5_RTS;
116 cs->cs_preg[12] = tconst;
117 cs->cs_preg[13] = tconst >> 8;
118
119 s = splhigh();
120 zs_loadchannelregs(cs);
121 splx(s);
122 }
123
124 /*
125 * Set up for kgdb; called at boot time before configuration.
126 * KGDB interrupts will be enabled later when zs0 is configured.
127 * Called after cninit(), so printf() etc. works.
128 */
129 void
zs_kgdb_init(void)130 zs_kgdb_init(void)
131 {
132 struct zs_chanstate cs;
133 volatile struct zschan *zc;
134 int channel;
135 extern const struct cdevsw zstty_cdevsw;
136
137 printf("zs_kgdb_init: kgdb_dev=0x%llx\n", kgdb_dev);
138 if (cdevsw_lookup(kgdb_dev) != &zstty_cdevsw)
139 return;
140
141 /* Note: (ttya,ttyb) on zs0, and (ttyc,ttyd) on zs2 */
142 channel = kgdb_dev & 1;
143 printf("zs_kgdb_init: attaching to Serial(%lld) at %d baud\n",
144 (kgdb_dev & 3), kgdb_rate);
145
146 /* Setup temporary chanstate. */
147 memset(&cs, 0, sizeof(cs));
148 zc = zs_get_chan_addr(channel);
149
150 if (zc == NULL) {
151 printf("zs_kgdb_init: zs not mapped.\n");
152 kgdb_dev = -1;
153 return;
154 }
155
156 cs.cs_channel = channel;
157 cs.cs_brg_clk = PCLK / 16;
158 cs.cs_reg_csr = &zc->zc_csr;
159 cs.cs_reg_data = &zc->zc_data;
160
161 /* Now set parameters. (interrupts disabled) */
162 zs_setparam(&cs, 0, kgdb_rate);
163
164 /* Store the getc/putc functions and arg. */
165 kgdb_attach(zs_getc, zs_putc, __UNVOLATILE(zc));
166 }
167
168 /*
169 * This is a "hook" called by zstty_attach to allow the tty
170 * to be "taken over" for exclusive use by kgdb.
171 * Return non-zero if this is the kgdb port.
172 *
173 * Set the speed to kgdb_rate, CS8, etc.
174 */
175 int
zs_check_kgdb(struct zs_chanstate * cs,int dev)176 zs_check_kgdb(struct zs_chanstate *cs, int dev)
177 {
178
179 if (dev != kgdb_dev)
180 return (0);
181
182 /*
183 * Yes, this is port in use by kgdb.
184 */
185 cs->cs_private = NULL;
186 cs->cs_ops = &zsops_kgdb;
187
188 /* Now set parameters. (interrupts enabled) */
189 zs_setparam(cs, 1, kgdb_rate);
190
191 return (1);
192 }
193
194 /*
195 * KGDB framing character received: enter kernel debugger. This probably
196 * should time out after a few seconds to avoid hanging on spurious input.
197 */
198 void
zskgdb(struct zs_chanstate * cs)199 zskgdb(struct zs_chanstate *cs)
200 {
201 int unit = minor(kgdb_dev);
202
203 printf("zstty%d: kgdb interrupt\n", unit);
204 /* This will trap into the debugger. */
205 kgdb_connect(1);
206 }
207
208
209 /****************************************************************
210 * Interface to the lower layer (zscc)
211 ****************************************************************/
212
213 static void zs_kgdb_rxint(struct zs_chanstate *);
214 static void zs_kgdb_stint(struct zs_chanstate *, int);
215 static void zs_kgdb_txint(struct zs_chanstate *);
216 static void zs_kgdb_softint(struct zs_chanstate *);
217
218 int kgdb_input_lost;
219
220 static void
zs_kgdb_rxint(struct zs_chanstate * cs)221 zs_kgdb_rxint(struct zs_chanstate *cs)
222 {
223 uint8_t c, rr1;
224
225 /*
226 * First read the status, because reading the received char
227 * destroys the status of this char.
228 */
229 rr1 = zs_read_reg(cs, 1);
230 c = zs_read_data(cs);
231
232 if (rr1 & (ZSRR1_FE | ZSRR1_DO | ZSRR1_PE)) {
233 /* Clear the receive error. */
234 zs_write_csr(cs, ZSWR0_RESET_ERRORS);
235 }
236
237 if (c == KGDB_START) {
238 zskgdb(cs);
239 } else {
240 kgdb_input_lost++;
241 }
242 }
243
244 static void
zs_kgdb_txint(struct zs_chanstate * cs)245 zs_kgdb_txint(struct zs_chanstate *cs)
246 {
247 zs_write_csr(cs, ZSWR0_RESET_TXINT);
248 }
249
250 static void
zs_kgdb_stint(struct zs_chanstate * cs,int force)251 zs_kgdb_stint(struct zs_chanstate *cs, int force)
252 {
253 int rr0;
254
255 rr0 = zs_read_csr(cs);
256 zs_write_csr(cs, ZSWR0_RESET_STATUS);
257
258 /*
259 * Check here for console break, so that we can abort
260 * even when interrupts are locking up the machine.
261 */
262 if (rr0 & ZSRR0_BREAK) {
263 zskgdb(cs);
264 }
265 }
266
267 static void
zs_kgdb_softint(struct zs_chanstate * cs)268 zs_kgdb_softint(struct zs_chanstate *cs)
269 {
270 printf("zs_kgdb_softint?\n");
271 }
272
273 struct zsops zsops_kgdb = {
274 zs_kgdb_rxint, /* receive char available */
275 zs_kgdb_stint, /* external/status */
276 zs_kgdb_txint, /* xmit buffer empty */
277 zs_kgdb_softint, /* process software interrupt */
278 };
279