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cortexa: Use fast mode for APB mem access and allow byte access.

This commit is contained in:
Gareth McMullin 2016-06-30 17:56:01 +12:00
parent d16aca9ae0
commit 4596d88f72
1 changed files with 76 additions and 38 deletions
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104
src/cortexa.c
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@ -99,6 +99,7 @@ struct cortexa_priv {
#define DBGDSCR_TXFULL (1 << 29)
#define DBGDSCR_INSTRCOMPL (1 << 24)
#define DBGDSCR_EXTDCCMODE_STALL (1 << 20)
#define DBGDSCR_EXTDCCMODE_FAST (2 << 20)
#define DBGDSCR_EXTDCCMODE_MASK (3 << 20)
#define DBGDSCR_HDBGEN (1 << 14)
#define DBGDSCR_ITREN (1 << 13)
@ -243,29 +244,40 @@ static void cortexa_mem_read(target *t, void *dest, uint32_t src, size_t len)
static void cortexa_slow_mem_read(target *t, void *dest, uint32_t src, size_t len)
{
struct cortexa_priv *priv = t->priv;
if ((src & 3) || (len & 3)) {
priv->mmu_fault = true;
return;
}
unsigned words = (len + (src & 3) + 3) / 4;
uint32_t dest32[words];
/* Set r0 to aligned src address */
write_gpreg(t, 0, src & ~3);
/* Switch to fast DCC mode */
uint32_t dbgdscr = apb_read(t, DBGDSCR);
dbgdscr = (dbgdscr & ~DBGDSCR_EXTDCCMODE_MASK) | DBGDSCR_EXTDCCMODE_FAST;
apb_write(t, DBGDSCR, dbgdscr);
apb_write(t, DBGITR, 0xecb05e01); /* ldc 14, cr5, [r0], #4 */
/* According to the ARMv7-A ARM, in fast mode, the first read from
* DBGDTRTX is supposed to block until the instruction is complete,
* but we see the first read returns junk, so it's read here and
* ignored. */
apb_read(t, DBGDTRTX);
for (unsigned i = 0; i < words; i++)
dest32[i] = apb_read(t, DBGDTRTX);
memcpy(dest, (uint8_t*)dest32 + (src & 3), len);
/* Switch back to stalling DCC mode */
dbgdscr = (dbgdscr & ~DBGDSCR_EXTDCCMODE_MASK) | DBGDSCR_EXTDCCMODE_STALL;
apb_write(t, DBGDSCR, dbgdscr);
/* No AHB :C Do slow read through debug APB */
/* Set SP to src address */
write_gpreg(t, 13, src);
uint32_t *dest32 = dest;
do {
apb_write(t, DBGITR, 0xe8bd00ff); /* pop {r0, r1, r2, r3, r4, r5, r6, r7} */
if (apb_read(t, DBGDSCR) & DBGDSCR_SDABORT_L) {
/* Memory access aborted, flag a fault */
apb_write(t, DBGDRCR, DBGDRCR_CSE);
priv->mmu_fault = true;
return;
} else {
apb_read(t, DBGDTRTX);
}
for (int i = 0; i < 8; i++) {
*dest32++ = read_gpreg(t, i);
len -= 4;
if (len <= 0) break;
}
} while (len > 0);
}
static void cortexa_mem_write(target *t, uint32_t dest, const void *src, size_t len)
@ -280,32 +292,58 @@ static void cortexa_mem_write(target *t, uint32_t dest, const void *src, size_t
adiv5_mem_write(ahb, va_to_pa(t, dest), src, len);
}
static void cortexa_slow_mem_write(target *t, uint32_t dest, const void *src, size_t len)
static void cortexa_slow_mem_write_bytes(target *t, uint32_t dest, const uint8_t *src, size_t len)
{
struct cortexa_priv *priv = t->priv;
if ((dest & 3) || (dest & 3)) {
priv->mmu_fault = true;
return;
}
/* No AHB :C Do slow write through debug APB */
/* Set SP to dest address */
/* Set r13 to dest address */
write_gpreg(t, 13, dest);
const uint32_t *src32 = src;
do {
for (int i = 0; i < 8; i++) {
write_gpreg(t, i, *src32++);
len -= 4;
if (len <= 0) break;
}
apb_write(t, DBGITR, 0xe8ad00ff); /* stmia sp!, {r0, r1, r2, r3, r4, r5, r6, r7} */
while (len--) {
write_gpreg(t, 0, *src++);
apb_write(t, DBGITR, 0xe4cd0001); /* strb r0, [sp], #1 */
if (apb_read(t, DBGDSCR) & DBGDSCR_SDABORT_L) {
/* Memory access aborted, flag a fault */
apb_write(t, DBGDRCR, DBGDRCR_CSE);
priv->mmu_fault = true;
return;
}
} while (len > 0);
}
}
static void cortexa_slow_mem_write(target *t, uint32_t dest, const void *src, size_t len)
{
struct cortexa_priv *priv = t->priv;
if (len == 0)
return;
if ((dest & 3) || (len & 3)) {
cortexa_slow_mem_write_bytes(t, dest, src, len);
return;
}
write_gpreg(t, 0, dest);
const uint32_t *src32 = src;
/* Switch to fast DCC mode */
uint32_t dbgdscr = apb_read(t, DBGDSCR);
dbgdscr = (dbgdscr & ~DBGDSCR_EXTDCCMODE_MASK) | DBGDSCR_EXTDCCMODE_FAST;
apb_write(t, DBGDSCR, dbgdscr);
apb_write(t, DBGITR, 0xeca05e01); /* stc 14, cr5, [r0], #4 */
for (; len; len -= 4)
apb_write(t, DBGDTRRX, *src32++);
/* Switch back to stalling DCC mode */
dbgdscr = (dbgdscr & ~DBGDSCR_EXTDCCMODE_MASK) | DBGDSCR_EXTDCCMODE_STALL;
apb_write(t, DBGDSCR, dbgdscr);
if (apb_read(t, DBGDSCR) & DBGDSCR_SDABORT_L) {
/* Memory access aborted, flag a fault */
apb_write(t, DBGDRCR, DBGDRCR_CSE);
priv->mmu_fault = true;
}
}
static bool cortexa_check_error(target *t)