rockbox/gdb/arm-stub.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 by Tomasz Malesinski
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdbool.h>
#include <string.h>
#include "usb_serial.h"
#include "sscanf.h"
#define BUFMAX 1024
#define VEC_UND 1
#define VEC_SWI 2
#define VEC_PABT 3
#define VEC_DABT 4
static char packet_buf[BUFMAX];
static char reply_buf[BUFMAX];
static const char hexchars[] = "0123456789abcdef";
static int gdb_exception_no, gdb_mem_access;
static unsigned long registers[17];
static inline bool isxdigit(char c)
{
return ((c >= '0') && (c <= '9'))
|| ((c >= 'a') && (c <= 'f')) || ((c >= 'A') && (c <= 'F'));
}
static int hex(char ch) {
if ((ch >= 'a') && (ch <= 'f'))
return ch - 'a' + 10;
if ((ch >= '0') && (ch <= '9'))
return ch - '0';
if ((ch >= 'A') && (ch <= 'F'))
return ch - 'A' + 10;
return -1;
}
static void hex_byte(char *s, int byte) {
s[0] = hexchars[(byte >> 4) & 0xf];
s[1] = hexchars[byte & 0xf];
}
static void hex_word(char *s, unsigned long val) {
int i;
for (i = 0; i < 4; i++)
hex_byte(s + i * 2, (val >> (i * 8)) & 0xff);
}
static void hex_string(char *d, char *s) {
while (*s) {
hex_byte(d, *s++);
d += 2;
}
*d = 0;
}
static int get_hex_byte(char *s) {
return (hex(s[0]) << 4) + hex(s[1]);
}
static unsigned long get_hex_word(char *s) {
int i;
unsigned long r = 0;
for (i = 3; i >= 0; i--)
r = (r << 8) + get_hex_byte(s + i * 2);
return r;
}
static void reply_error(int n, char *reply) {
reply[0] = 'E';
hex_byte(reply + 1, n);
reply[3] = 0;
}
static void reply_signal(int n, char *reply) {
int signal;
reply[0] = 'S';
switch (n)
{
case VEC_UND:
signal = 4;
break;
case VEC_PABT:
case VEC_DABT:
signal = 7;
break;
default:
signal = 5;
break;
}
hex_byte(reply + 1, signal);
reply[3] = 0;
}
static void reply_ok(char *reply) {
strcpy(reply, "OK");
}
static void serial_write(unsigned char *buf, int len) {
int i;
for (i = 0; i < len; i++)
usb_serial_put_byte(buf[i]);
}
static void get_packet(char *buf, int len) {
int count, checksum;
int ch;
while (1) {
do {
ch = usb_serial_get_byte();
} while (ch != '$');
checksum = 0;
count = 0;
while (count < len) {
ch = usb_serial_get_byte();
if (ch == '$') {
checksum = 0;
count = 0;
} else if (ch == '#')
break;
else {
checksum += ch;
buf[count] = ch;
count++;
}
}
buf[count] = 0;
if (ch == '#') {
int rchksum;
ch = usb_serial_get_byte();
rchksum = hex(ch) << 4;
ch = usb_serial_get_byte();
rchksum += hex(ch);
if ((checksum & 0xff) != rchksum)
usb_serial_put_byte('-');
else {
usb_serial_put_byte('+');
return;
}
}
}
}
static void put_packet(char *buf) {
int i, checksum;
int ch;
char tmp[3];
do {
usb_serial_put_byte('$');
checksum = 0;
for (i = 0; buf[i]; i++)
checksum += buf[i];
serial_write(buf, i);
tmp[0] = '#';
hex_byte(tmp + 1, checksum & 0xff);
serial_write(tmp, 3);
ch = usb_serial_get_byte();
} while (ch != '+');
}
static inline unsigned long get_general_reg(int n)
{
return registers[n + 1];
}
static inline void set_general_reg(int n, unsigned long v)
{
registers[n + 1] = v;
}
static inline unsigned long get_cpsr(void)
{
return registers[0];
}
static inline void set_cpsr(unsigned long v)
{
registers[0] = v;
}
static void g_reply(char *buf) {
int i;
char *p;
p = buf;
for (i = 0; i < 16; i++) {
hex_word(p, get_general_reg(i));
p += 8;
}
for (i = 0; i < 8; i++) {
memset(p, '0', 16);
p += 16;
}
hex_word(p, 0);
p += 8;
hex_word(p, get_cpsr());
p[8] = 0;
}
static void cmd_get_register(char *args, char *reply) {
int r;
if (sscanf(args, "%x", &r) != 1) {
reply_error(0, reply);
return;
}
if (r >= 0 && r < 16) {
hex_word(reply, get_general_reg(r));
reply[8] = 0;
} else if (r == 25) {
hex_word(reply, get_cpsr());
reply[8] = 0;
} else {
hex_word(reply, 0);
reply[8] = 0;
}
}
static void cmd_set_register(char *args, char *reply) {
int r, p;
unsigned long v;
p = -1;
sscanf(args, "%x=%n", &r, &p);
if (p == -1) {
reply_error(0, reply);
return;
}
v = get_hex_word(args + p);
if (r >= 0 && r < 16)
set_general_reg(r, v);
else if (r == 25)
set_cpsr(v);
reply_ok(reply);
}
static void cmd_set_registers(char *args, char *reply) {
char *p;
int i, len;
len = strlen(args);
p = args;
for (i = 0; i < 16 && len >= (i + 1) * 8; i++) {
set_general_reg(i, get_hex_word(p));
p += 8;
}
if (len >= 16 * 8 + 8 * 16 + 2 * 8)
{
p += 8 * 16 + 8;
set_cpsr(get_hex_word(p));
}
reply_ok(reply);
}
static void cmd_get_memory(char *args, char *reply) {
unsigned long addr, len, i;
if (sscanf(args, "%lx,%lx", &addr, &len) != 2) {
reply_error(0, reply);
return;
}
if (len > (BUFMAX - 16) / 2) {
reply_error(1, reply);
return;
}
gdb_mem_access = 1;
for (i = 0; i < len; i++)
hex_byte(reply + i * 2, *((unsigned char *)(addr + i)));
gdb_mem_access = 0;
reply[len * 2] = 0;
}
static void cmd_put_memory(char *args, char *reply) {
unsigned long addr, len, i;
int pos;
pos = -1;
sscanf(args, "%lx,%lx:%n", &addr, &len, &pos);
if (pos == -1) {
reply_error(0, reply);
return;
}
gdb_mem_access = 1;
for (i = 0; i < len; i++)
*((unsigned char *)(addr + i)) = get_hex_byte(args + pos + i * 2);
gdb_mem_access = 0;
reply_ok(reply);
}
static void parse_continue_args(char *args) {
int sig;
unsigned long addr;
if (sscanf(args, "%x;%lx", &sig, &addr) == 2) {
set_general_reg(15, addr);
} else if (sscanf(args, "%lx", &addr) == 1) {
set_general_reg(15, addr);
}
}
static void cmd_go(char *args) {
parse_continue_args(args);
asm volatile(
" mov r1, %0\n"
" ldr r12, [r1], #4\n"
" mov r0, r12\n"
" and r0, r0, #0x1f\n"
" cmp r0, #0x10\n"
" bne 1f\n"
" ldr r14, [r1, #60]\n"
" msr spsr_fsxc, r12\n"
" ldmia r1, {r0-r14}^\n"
" movs r15, r14\n"
"1:\n"
" msr cpsr_fsxc, r12\n"
" ldmia r1, {r0-r15}\n"
: : "r" (registers));
}
static void remote_cmd(char *cmd, char *reply) {
(void)cmd;
hex_string(reply, "Unrecognized command\n");
}
static void cmd_query(char *args, char *reply) {
if (!strncmp(args, "Rcmd,", 5)) {
unsigned i = 0;
char *s = args + 5;
char cmd[200];
while (isxdigit(s[0]) && isxdigit(s[1]) && i < sizeof(cmd) - 1) {
cmd[i++] = get_hex_byte(s);
s += 2;
}
cmd[i] = 0;
remote_cmd(cmd, reply);
} else
reply[0] = 0;
}
void gdb_loop(void) {
int no_reply;
gdb_mem_access = 0;
while (1) {
get_packet(packet_buf, sizeof(packet_buf) - 1);
no_reply = 0;
switch (packet_buf[0]) {
case '?':
reply_signal(gdb_exception_no, reply_buf);
break;
case 'p':
cmd_get_register(packet_buf + 1, reply_buf);
break;
case 'P':
cmd_set_register(packet_buf + 1, reply_buf);
break;
case 'g':
g_reply(reply_buf);
break;
case 'G':
cmd_set_registers(packet_buf + 1, reply_buf);
break;
case 'm':
cmd_get_memory(packet_buf + 1, reply_buf);
break;
case 'M':
cmd_put_memory(packet_buf + 1, reply_buf);
break;
case 'q':
cmd_query(packet_buf + 1, reply_buf);
break;
case 'c':
cmd_go(packet_buf + 1);
reply_error(1, reply_buf);
break;
/* case 's': */
/* cmd_go(packet_buf + 1); */
/* break; */
default:
reply_buf[0] = 0;
}
if (!no_reply)
put_packet(reply_buf);
}
}
extern void *vectors[];
static void gdb_set_vector(int n, void *p)
{
vectors[n] = p;
}
void gdb_und_exc(void);
void gdb_swi_exc(void);
void gdb_pabt_exc(void);
void gdb_dabt_exc(void);
static void gdb_set_vectors(void)
{
gdb_set_vector(VEC_UND, gdb_und_exc);
gdb_set_vector(VEC_SWI, gdb_swi_exc);
gdb_set_vector(VEC_PABT, gdb_pabt_exc);
gdb_set_vector(VEC_DABT, gdb_dabt_exc);
}
void gdb_loop_from_exc(void)
{
if (gdb_mem_access)
reply_error(1, reply_buf);
else
reply_signal(gdb_exception_no, reply_buf);
put_packet(reply_buf);
gdb_loop();
}
#define GPIO3_CLR (*(volatile unsigned long *)0x800030d8)
#define IRQ_REG(reg) (*(volatile unsigned long *)(0x80300000 + (reg)))
static inline unsigned long irq_read(int reg)
{
unsigned long v, v2;
do
{
v = IRQ_REG(reg);
v2 = IRQ_REG(reg);
} while (v != v2);
return v;
}
#define IRQ_WRITE_WAIT(reg, val, cond) \
do { unsigned long v, v2; \
do { \
IRQ_REG(reg) = (val); \
v = IRQ_REG(reg); \
v2 = IRQ_REG(reg); \
} while ((v != v2) || !(cond)); \
} while (0);
static void system_init(void)
{
int i;
/* turn off watchdog */
(*(volatile unsigned long *)0x80002804) = 0;
for (i = 0; i < 0x1c; i++)
{
IRQ_WRITE_WAIT(0x404 + i * 4, 0x1e000001, (v & 0x3010f) == 1);
IRQ_WRITE_WAIT(0x404 + i * 4, 0x4000000, (v & 0x10000) == 0);
IRQ_WRITE_WAIT(0x404 + i * 4, 0x10000001, (v & 0xf) == 1);
}
GPIO3_CLR = 1;
}
void main(void)
{
system_init();
usb_serial_init();
gdb_exception_no = VEC_SWI;
gdb_set_vectors();
gdb_loop();
}
#define str(s) #s
#define xstr(s) str(s)
asm (".text\n"
"gdb_und_exc:\n"
" ldr sp, =_stub_stack\n"
" sub r14, r14, #4\n"
" stmfd sp!, {r0-r3, r12, r14}\n"
" mov r0, #" xstr(VEC_UND) "\n"
" b gdb_handle_exception\n"
"gdb_swi_exc:\n"
" ldr sp, =_stub_stack\n"
" stmfd sp!, {r0-r3, r12, r14}\n"
" mov r0, #" xstr(VEC_SWI) "\n"
" b gdb_handle_exception\n"
"gdb_pabt_exc:\n"
" ldr sp, =_stub_stack\n"
" stmfd sp!, {r0-r3, r12, r14}\n"
" mov r0, #" xstr(VEC_PABT) "\n"
" b gdb_handle_exception\n"
"gdb_dabt_exc:\n"
" ldr sp, =_stub_stack\n"
" sub r14, r14, #4\n"
" stmfd sp!, {r0-r3, r12, r14}\n"
" ldr r0, =gdb_mem_access\n"
" ldr r0, [r0]\n"
" tst r0, r0\n"
" bne gdb_data_abort\n"
" mov r0, #" xstr(VEC_DABT) "\n"
" b gdb_handle_exception\n"
"gdb_handle_exception:\n"
" ldr r1, =gdb_exception_no\n"
" str r0, [r1]\n"
" ldr r0, =registers\n"
" mrs r12, spsr\n"
" str r12, [r0], #4\n"
" ldmfd sp!, {r2, r3}\n"
" stmia r0!, {r2, r3}\n"
" ldmfd sp!, {r2, r3, r12, r14}\n"
" str r14, [r0, #52]\n"
" stmia r0!, {r2-r12}\n"
" mrs r1, spsr\n"
" and r2, r1, #0x1f\n"
" cmp r2, #0x10\n"
" bne 1f\n"
" stmia r0, {r13, r14}^\n"
" b gdb_data_abort\n"
"1:\n"
" msr cpsr_c, r1\n"
" stmia r0, {r13, r14}\n"
"gdb_data_abort:\n"
" msr cpsr_c, #0xd3\n"
" ldr sp, =_stub_stack\n"
" b gdb_loop_from_exc\n");