* Copyright (c) 1996 The NetBSD Foundation, Inc.

/* $NetBSD: zs_kgdb.c,v 1.22 2023/10/24 19:05:07 andvar Exp $ */

/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Gordon W. Ross.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

/*
* Hooks for kgdb when attached via the z8530 driver
*
* To use this, build a kernel with: option KGDB, and
* boot that kernel with "-d". (The kernel will call
* zs_kgdb_init, kgdb_connect.) When the console prints
* "kgdb waiting..." you run "gdb -k kernel" and do:
* (gdb) set remotebaud 19200
* (gdb) target remote /dev/ttyb
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: zs_kgdb.c,v 1.22 2023/10/24 19:05:07 andvar Exp $");

#include "opt_kgdb.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/ioctl.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/kgdb.h>

#include <dev/ic/z8530reg.h>
#include <machine/z8530var.h>
#include <machine/autoconf.h>
#include <machine/promlib.h>
#include <sparc/dev/cons.h>

/* Suns provide a 4.9152 MHz clock to the ZS chips. */
#define PCLK (9600 * 512) /* PCLK pin input clock rate */

/* The layout of this is hardware-dependent (padding, order). */
struct zschan {
volatile u_char zc_csr; /* ctrl,status, and indirect access */
u_char zc_xxx0;
volatile u_char zc_data; /* data */
u_char zc_xxx1;
};
struct zsdevice {
/* Yes, they are backwards. */
struct zschan zs_chan_b;
struct zschan zs_chan_a;
};

static void zs_setparam(struct zs_chanstate *, int, int);
static void *findzs(int);
struct zsops zsops_kgdb;

extern int zs_getc(void *);
extern void zs_putc(void *, int);

static u_char zs_kgdb_regs[16] = {
0, /* 0: CMD (reset, etc.) */
0, /* 1: No interrupts yet. */
0, /* 2: IVECT */
ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
0, /* 6: TXSYNC/SYNCLO */
0, /* 7: RXSYNC/SYNCHI */
0, /* 8: alias for data port */
ZSWR9_MASTER_IE | ZSWR9_NO_VECTOR,
0, /*10: Misc. TX/RX control bits */
ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
14, /*12: BAUDLO (default=9600) */
0, /*13: BAUDHI (default=9600) */
ZSWR14_BAUD_ENA | ZSWR14_BAUD_FROM_PCLK,
ZSWR15_BREAK_IE,
};

/*
* This replaces "zs_reset()" in the sparc driver.
*/
static void
zs_setparam(struct zs_chanstate *cs, int iena, int rate)
{
int s, tconst;

memcpy(cs->cs_preg, zs_kgdb_regs, 16);

if (iena) {
cs->cs_preg[1] = ZSWR1_RIE | ZSWR1_SIE;
}

/* Initialize the speed, etc. */
tconst = BPS_TO_TCONST(cs->cs_brg_clk, rate);
cs->cs_preg[5] |= ZSWR5_DTR | ZSWR5_RTS;
cs->cs_preg[12] = tconst;
cs->cs_preg[13] = tconst >> 8;

s = splhigh();
zs_loadchannelregs(cs);
splx(s);
}

/*
* Set up for kgdb; called at boot time before configuration.
* KGDB interrupts will be enabled later when zs0 is configured.
* Called after cninit(), so printf() etc. works.
*/
void
zs_kgdb_init(void)
{
struct zs_chanstate cs;
struct zsdevice *zsd;
volatile struct zschan *zc;
int channel, promzs_unit;
extern const struct cdevsw zstty_cdevsw;

/* printf("zs_kgdb_init: kgdb_dev=0x%x\n", kgdb_dev); */
if (cdevsw_lookup(kgdb_dev) != &zstty_cdevsw)
return;

/* Note: (ttya,ttyb) on zs0, and (ttyc,ttyd) on zs2 */
promzs_unit = (kgdb_dev & 2) ? 2 : 0;
channel = kgdb_dev & 1;
printf("zs_kgdb_init: attaching Serial(%lld) at %d baud\n",
(kgdb_dev & 3), kgdb_rate);

/* Setup temporary chanstate. */
memset((void *)&cs, 0, sizeof(cs));
zsd = findzs(promzs_unit);
if (zsd == NULL) {
printf("zs_kgdb_init: zs not mapped.\n");
return;
}
zc = (channel == 0) ? &zsd->zs_chan_a : &zsd->zs_chan_b;

cs.cs_channel = channel;
cs.cs_brg_clk = PCLK / 16;
cs.cs_reg_csr = &zc->zc_csr;
cs.cs_reg_data = &zc->zc_data;

/* Now set parameters. (interrupts disabled) */
zs_setparam(&cs, 0, kgdb_rate);

/* Store the getc/putc functions and arg. */
kgdb_attach(zs_getc, zs_putc, __UNVOLATILE(zc));
}

/*
* This is a "hook" called by zstty_attach to allow the tty
* to be "taken over" for exclusive use by kgdb.
* Return non-zero if this is the kgdb port.
*
* Set the speed to kgdb_rate, CS8, etc.
*/
int
zs_check_kgdb(struct zs_chanstate *cs, int dev)
{

if (dev != kgdb_dev)
return (0);

/*
* Yes, this is port in use by kgdb.
*/
cs->cs_private = NULL;
cs->cs_ops = &zsops_kgdb;

/* Now set parameters. (interrupts enabled) */
zs_setparam(cs, 1, kgdb_rate);

return (1);
}

/*
* KGDB framing character received: enter kernel debugger. This probably
* should time out after a few seconds to avoid hanging on spurious input.
*/
void
zskgdb(struct zs_chanstate *cs)
{
int unit = minor(kgdb_dev);

printf("zstty%d: kgdb interrupt\n", unit);
/* This will trap into the debugger. */
kgdb_connect(1);
}

/****************************************************************
* Interface to the lower layer (zscc)
****************************************************************/

static void zs_kgdb_rxint(struct zs_chanstate *);
static void zs_kgdb_stint(struct zs_chanstate *, int);
static void zs_kgdb_txint(struct zs_chanstate *);
static void zs_kgdb_softint(struct zs_chanstate *);

int kgdb_input_lost;

static void
zs_kgdb_rxint(struct zs_chanstate *cs)
{
register u_char c, rr1;

/*
* First read the status, because reading the received char
* destroys the status of this char.
*/
rr1 = zs_read_reg(cs, 1);
c = zs_read_data(cs);

if (rr1 & (ZSRR1_FE | ZSRR1_DO | ZSRR1_PE)) {
/* Clear the receive error. */
zs_write_csr(cs, ZSWR0_RESET_ERRORS);
}

if (c == KGDB_START) {
zskgdb(cs);
} else {
kgdb_input_lost++;
}
}

static void
zs_kgdb_txint(struct zs_chanstate *cs)
{
zs_write_csr(cs, ZSWR0_RESET_TXINT);
}

static void
zs_kgdb_stint(struct zs_chanstate *cs, int force)
{
register int rr0;

rr0 = zs_read_csr(cs);
zs_write_csr(cs, ZSWR0_RESET_STATUS);

/*
* Check here for console break, so that we can abort
* even when interrupts are locking up the machine.
*/
if (rr0 & ZSRR0_BREAK) {
zskgdb(cs);
}
}

static void
zs_kgdb_softint(struct zs_chanstate *cs)
{

printf("zs_kgdb_softint?\n");
}

struct zsops zsops_kgdb = {
zs_kgdb_rxint, /* receive char available */
zs_kgdb_stint, /* external/status */
zs_kgdb_txint, /* xmit buffer empty */
zs_kgdb_softint, /* process software interrupt */
};

/*
* findzs() should return the address of the given zs channel.
* Here we count on the PROM to map in the required zs chips.
*/
static void *
findzs(int zs)
{

#if defined(SUN4)
if (CPU_ISSUN4) {
/*
* On sun4, we use hard-coded physical addresses
*/
#define ZS0_PHYS 0xf1000000
#define ZS1_PHYS 0xf0000000
#define ZS2_PHYS 0xe0000000
bus_space_handle_t bh;
bus_addr_t paddr;

switch (zs) {
case 0:
paddr = ZS0_PHYS;
break;
case 1:
paddr = ZS1_PHYS;
break;
case 2:
paddr = ZS2_PHYS;
break;
default:
return (NULL);
}

if (cpuinfo.cpu_type == CPUTYP_4_100)
/* Clear top bits of physical address on 4/100 */
paddr &= ~0xf0000000;

/*
* Have the obio module figure out which virtual
* address the device is mapped to.
*/
if (obio_find_rom_map(paddr, PAGE_SIZE, &bh) != 0)
return (NULL);

return ((void *)bh);
}
#endif

#if defined(SUN4C) || defined(SUN4M)
if (CPU_ISSUN4C || CPU_ISSUN4M) {
int node;

node = firstchild(findroot());
if (CPU_ISSUN4M) {
/*
* On sun4m machines zs is in "obio" tree.
*/
node = findnode(node, "obio");
if (node == 0)
panic("findzs: no obio node");
node = firstchild(node);
}
while ((node = findnode(node, "zs")) != 0) {
int nvaddrs, *vaddrs, vstore[10];

if (prom_getpropint(node, "slave", -1) != zs) {
node = nextsibling(node);
continue;
}

/*
* On some machines (e.g. the Voyager), the zs
* device has multi-valued register properties.
*/
vaddrs = vstore;
nvaddrs = sizeof(vstore)/sizeof(vstore[0]);
if (prom_getprop(node, "address", sizeof(int),
&nvaddrs, &vaddrs) != 0)
return (NULL);

return ((void *)vaddrs[0]);
}
}
#endif
return (NULL);
}