sys/arch/mac68k/dev/zs_kgdb.c

   1 /*      $NetBSD: zs_kgdb.c,v 1.10 2007/10/17 19:55:14 garbled 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 1.10 2007/10/17 19:55:14 garbled Exp $");
  45
  46 #include "opt_kgdb.h"
  47 #include <sys/param.h>
  48 #include <sys/systm.h>
  49 #include <sys/proc.h>
  50 #include <sys/device.h>
  51 #include <sys/conf.h>
  52 #include <sys/ioctl.h>
  53 #include <sys/kernel.h>
  54 #include <sys/syslog.h>
  55 #include <sys/kgdb.h>
  56
  57 #include <dev/ic/z8530reg.h>
  58 #include <machine/z8530var.h>
  59 #include <mac68k/dev/zs_cons.h>
  60
  61 /*
  62  * Macs supposely provide a 3.672 MHz clock to the SCC.  Unfortunately,
  63  * empirical evidence suggests that it's really a 3.6864 MHz clock.
  64  * Oh, what to do, what to do?!
  65  */
  66 #define PCLK    (9600 * 384)    /* PCLK pin input clock rate */
  67 #define ZSHARD_PRI      4       /* Wired on the CPU board... */
  68
  69 #define ZS_DELAY()                      delay(2)
  70
  71 /* The layout of this is hardware-dependent (padding, order). */
  72 struct zschan {
  73         volatile u_char zc_csr;         /* ctrl,status, and indirect access */
  74         u_char          zc_xxx0;
  75         u_char          zc_xxx1;        /* part of the other channel lives here! */
  76         u_char          zc_xxx2;        /* Yea Apple! */
  77         volatile u_char zc_data;        /* data */
  78         u_char          zc_xxx3;
  79         u_char          zc_xxx4;
  80         u_char          zc_xxx5;
  81 };
  82
  83 static void zs_setparam(struct zs_chanstate *, int, int);
  84 static void zskgdb(struct zs_chanstate *);
  85
  86 struct zsops zsops_kgdb;
  87
  88 static u_char zs_kgdb_regs[16] = {
  89         0,      /* 0: CMD (reset, etc.) */
  90         0,      /* 1: ~(ZSWR1_RIE | ZSWR1_TIE | ZSWR1_SIE) */
  91         0x18 + ZSHARD_PRI,      /* IVECT */
  92         ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
  93         ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
  94         ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
  95         0,      /* 6: TXSYNC/SYNCLO */
  96         0,      /* 7: RXSYNC/SYNCHI */
  97         0,      /* 8: alias for data port */
  98         ZSWR9_MASTER_IE,
  99         0,      /*10: Misc. TX/RX control bits */
 100         ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
 101         14,     /*12: BAUDLO (default=9600) */
 102         0,      /*13: BAUDHI (default=9600) */
 103         ZSWR14_BAUD_FROM_PCLK | ZSWR14_BAUD_ENA,
 104         ZSWR15_BREAK_IE,
 105 };
 106
 107 /*
 108  * This replaces "zs_reset()" in the sparc driver.
 109  */
 110 static void
 111 zs_setparam(struct zs_chanstate *cs, int iena, int rate)
 112 {
 113         int s, tconst;
 114
 115         memcpy(cs->cs_preg, zs_kgdb_regs, 16);
 116
 117         if (iena) {
 118                 cs->cs_preg[1] = ZSWR1_RIE | ZSWR1_SIE;
 119         }
 120
 121         /* Initialize the speed, etc. */
 122         tconst = BPS_TO_TCONST(cs->cs_brg_clk, rate);
 123         cs->cs_preg[5] |= ZSWR5_DTR | ZSWR5_RTS;
 124         cs->cs_preg[12] = tconst;
 125         cs->cs_preg[13] = tconst >> 8;
 126
 127         s = splhigh();
 128         zs_loadchannelregs(cs);
 129         splx(s);
 130 }
 131
 132 /*
 133  * Set up for kgdb; called at boot time before configuration.
 134  * KGDB interrupts will be enabled later when zs0 is configured.
 135  * Called after cninit(), so printf() etc. works.
 136  */
 137 void
 138 zs_kgdb_init(void)
 139 {
 140         struct zs_chanstate cs;
 141         volatile struct zschan *zc;
 142         int channel;
 143         extern const struct cdevsw zstty_cdevsw;
 144
 145         /* printf("zs_kgdb_init: kgdb_dev=0x%x\n", kgdb_dev); */
 146         if (cdevsw_lookup(kgdb_dev) != &zstty_cdevsw)
 147                 return;
 148
 149         /* Note: (ttya,ttyb) on zsc1, and (ttyc,ttyd) on zsc0 */
 150         channel = kgdb_dev & 1;
 151         printf("zs_kgdb_init: attaching tty0%c at %d baud\n",
 152                    '0' + (kgdb_dev & 3), kgdb_rate);
 153
 154         if (!zsinited)
 155                 zs_init();
 156
 157         /* Setup temporary chanstate. */
 158         memset(&cs, 0, sizeof(cs));
 159         zc = zs_get_chan_addr(channel);
 160         if (zc == NULL) {
 161                 printf("zs_kgdb_init: zs not mapped.\n");
 162                 kgdb_dev = -1;
 163                 return;
 164         }
 165
 166         cs.cs_channel = channel;
 167         cs.cs_brg_clk = PCLK / 16;
 168         cs.cs_reg_csr  = &zc->zc_csr;
 169         cs.cs_reg_data = &zc->zc_data;
 170
 171         /* Now set parameters. (interrupts disabled) */
 172         zs_setparam(&cs, 0, kgdb_rate);
 173
 174         /* Store the getc/putc functions and arg. */
 175         kgdb_attach(zs_getc, zs_putc, __UNVOLATILE(zc));
 176 }
 177
 178 /*
 179  * This is a "hook" called by zstty_attach to allow the tty
 180  * to be "taken over" for exclusive use by kgdb.
 181  * Return non-zero if this is the kgdb port.
 182  *
 183  * Set the speed to kgdb_rate, CS8, etc.
 184  */
 185 int
 186 zs_check_kgdb(struct zs_chanstate *cs, int dev)
 187 {
 188
 189         if (dev != kgdb_dev)
 190                 return (0);
 191
 192         /*
 193          * Yes, this is port in use by kgdb.
 194          */
 195         cs->cs_private = NULL;
 196         cs->cs_ops = &zsops_kgdb;
 197
 198         /* Now set parameters. (interrupts enabled) */
 199         zs_setparam(cs, 1, kgdb_rate);
 200
 201         return (1);
 202 }
 203
 204 /*
 205  * KGDB framing character received: enter kernel debugger.  This probably
 206  * should time out after a few seconds to avoid hanging on spurious input.
 207  */
 208 static void
 209 zskgdb(struct zs_chanstate *cs)
 210 {
 211         int unit = minor(kgdb_dev);
 212
 213         printf("zstty%d: kgdb interrupt\n", unit);
 214         /* This will trap into the debugger. */
 215         kgdb_connect(1);
 216 }
 217
 218
 219 /****************************************************************
 220  * Interface to the lower layer (zscc)
 221  ****************************************************************/
 222
 223 static void zs_kgdb_rxint(struct zs_chanstate *);
 224 static void zs_kgdb_stint(struct zs_chanstate *, int);
 225 static void zs_kgdb_txint(struct zs_chanstate *);
 226 static void zs_kgdb_softint(struct zs_chanstate *);
 227
 228 int kgdb_input_lost;
 229
 230 static void
 231 zs_kgdb_rxint(struct zs_chanstate *cs)
 232 {
 233         u_char c, rr1;
 234
 235         /*
 236          * First read the status, because reading the received char
 237          * destroys the status of this char.
 238          */
 239         rr1 = zs_read_reg(cs, 1);
 240         c = zs_read_data(cs);
 241
 242         if (rr1 & (ZSRR1_FE | ZSRR1_DO | ZSRR1_PE)) {
 243                 /* Clear the receive error. */
 244                 zs_write_csr(cs, ZSWR0_RESET_ERRORS);
 245         }
 246
 247         if (c == KGDB_START) {
 248                 zskgdb(cs);
 249         } else {
 250                 kgdb_input_lost++;
 251         }
 252 }
 253
 254 static void
 255 zs_kgdb_txint(struct zs_chanstate *cs)
 256 {
 257         int rr0;
 258
 259         rr0 = zs_read_csr(cs);
 260         zs_write_csr(cs, ZSWR0_RESET_TXINT);
 261 }
 262
 263 static void
 264 zs_kgdb_stint(struct zs_chanstate *cs, int force)
 265 {
 266         int rr0;
 267
 268         rr0 = zs_read_csr(cs);
 269         zs_write_csr(cs, ZSWR0_RESET_STATUS);
 270
 271         /*
 272          * Check here for console break, so that we can abort
 273          * even when interrupts are locking up the machine.
 274          */
 275         if (rr0 & ZSRR0_BREAK) {
 276                 zskgdb(cs);
 277         }
 278 }
 279
 280 static void
 281 zs_kgdb_softint(struct zs_chanstate *cs)
 282 {
 283         printf("zs_kgdb_softint?\n");
 284 }
 285
 286 struct zsops zsops_kgdb = {
 287         zs_kgdb_rxint,  /* receive char available */
 288         zs_kgdb_stint,  /* external/status */
 289         zs_kgdb_txint,  /* xmit buffer empty */
 290         zs_kgdb_softint,        /* process software interrupt */
 291 };