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Fix: Avoid a hang in scanning Cortex-A of STM32MP15x #1628

Merged
merged 9 commits into from
Sep 23, 2023
107 changes: 100 additions & 7 deletions src/target/cortexa.c
Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,19 @@ typedef struct cortexa_priv {
#define CORTEXAR_DBG_WCR 0x1c0U
#define CORTEXAR_CTR 0xd04U

#define CORTEXAR_DBG_DSCCR 0x028U
#define CORTEXAR_DBG_DSMCR 0x02cU
#define CORTEXAR_DBG_OSLAR 0x300U
#define CORTEXAR_DBG_OSLSR 0x304U
#define CORTEXAR_DBG_LAR 0xfb0U /* Lock Access */
#define CORTEXAR_DBG_LSR 0xfb4U /* Lock Status */

#define DBGOSLSR_OSLM0 (1U << 0U)
#define DBGOSLSR_OSLK (1U << 1U)
#define DBGOSLSR_NTT (1U << 2U)
#define DBGOSLSR_OSLM1 (1U << 3U)
#define DBGOSLSR_OSLM (DBGOSLSR_OSLM0 | DBGOSLSR_OSLM1)
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#define CORTEXAR_DBG_IDR_BREAKPOINT_MASK 0xfU
#define CORTEXAR_DBG_IDR_BREAKPOINT_SHIFT 24U
#define CORTEXAR_DBG_IDR_WATCHPOINT_MASK 0xfU
Expand Down Expand Up @@ -317,6 +330,54 @@ static size_t create_tdesc_cortex_a(char *buffer, size_t max_len)
return (size_t)total;
}

typedef struct bitfield_entry {
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char *desc;
uint8_t bitnum;
} bitfields_lut_s;

static const bitfields_lut_s cortexa_dbg_dscr_lut[] = {
{"HALTED", 0U},
{"RESTARTED", 1U},
{"SDABORT_l", 6U},
{"ADABORT_l", 7U},
{"UND_l", 8U},
{"FS", 9U},
{"ITRen", 13U},
{"HDBGen", 14U},
{"MDBGen", 15U},
{"InstrCompl_l", 24U},
{"PipeAdv", 25U},
{"TXfull_l", 26U},
{"RXfull_l", 27U},
{"TXfull", 29U},
{"RXfull", 30U},
};

static void helper_print_bitfields(const uint32_t val, const bitfields_lut_s lut[], const size_t array_length)
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{
for (size_t i = 0; i < array_length; i++) {
if (val & (1U << lut[i].bitnum)) {
DEBUG_TARGET("%s ", lut[i].desc);
}
}
};
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static void cortexa_decode_bitfields(const uint32_t reg, const uint32_t val)
{
DEBUG_TARGET("Bits set in reg ");
switch (reg) {
case CORTEXAR_DBG_DSCR:
DEBUG_TARGET("DBGDSCR: ");
helper_print_bitfields(val, cortexa_dbg_dscr_lut, ARRAY_LENGTH(cortexa_dbg_dscr_lut));
break;
default:
DEBUG_TARGET("unknown reg");
break;
}

DEBUG_TARGET("\n");
}

static void cortexar_run_insn(target_s *const target, const uint32_t insn)
{
/* Issue the requested instruction to the core */
Expand Down Expand Up @@ -508,6 +569,45 @@ bool cortexa_probe(adiv5_access_port_s *ap, target_addr_t base_address)
target->halt_poll = cortexa_halt_poll;
target->halt_resume = cortexa_halt_resume;

#if 0
/* Reset 0xc5acce55 lock access to deter software */
cortex_dbg_write32(target, CORTEXAR_DBG_LAR, 0U);
/* Cache write-through */
cortex_dbg_write32(target, CORTEXAR_DBG_DSCCR, 0U);
/* Disable TLB lookup and refill/eviction */
cortex_dbg_write32(target, CORTEXAR_DBG_DSMCR, 0U);
#endif

uint32_t dbg_osreg = cortex_dbg_read32(target, CORTEXAR_DBG_OSLSR);
DEBUG_INFO("%s: DBGOSLSR = 0x%08X\n", __func__, dbg_osreg);
/* Is OS Lock implemented? */
if (((dbg_osreg & DBGOSLSR_OSLM) == DBGOSLSR_OSLM0) || ((dbg_osreg & DBGOSLSR_OSLM) == DBGOSLSR_OSLM1)) {
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/* Is OS Lock set? */
if (dbg_osreg & DBGOSLSR_OSLK) {
DEBUG_WARN("%s: OSLock set! Trying to unlock\n", __func__);
cortex_dbg_write32(target, CORTEXAR_DBG_OSLAR, 0U);
dbg_osreg = cortex_dbg_read32(target, CORTEXAR_DBG_OSLSR);

if ((dbg_osreg & DBGOSLSR_OSLK) != 0) {
DEBUG_ERROR("%s: OSLock sticky, core not powered?\n", __func__);
}
}
}

uint32_t dbgdscr = cortex_dbg_read32(target, CORTEXAR_DBG_DSCR);
DEBUG_INFO("%s: DBGDSCR = 0x%08" PRIx32 " (1)\n", __func__, dbgdscr);
cortexa_decode_bitfields(CORTEXAR_DBG_DSCR, dbgdscr);

/* Enable halting debug mode */
dbgdscr |= CORTEXAR_DBG_DSCR_HALT_DBG_ENABLE | CORTEXAR_DBG_DSCR_ITR_ENABLE;
cortex_dbg_write32(target, CORTEXAR_DBG_DSCR, dbgdscr);
dbgdscr &= ~DBGDSCR_EXTDCCMODE_MASK;
cortex_dbg_write32(target, CORTEXAR_DBG_DSCR, dbgdscr);

dbgdscr = cortex_dbg_read32(target, CORTEXAR_DBG_DSCR);
DEBUG_INFO("%s: DBGDSCR = 0x%08" PRIx32 " (2)\n", __func__, dbgdscr);
cortexa_decode_bitfields(CORTEXAR_DBG_DSCR, dbgdscr);

/* Try to halt the target core */
target_halt_request(target);
platform_timeout_s timeout;
Expand Down Expand Up @@ -569,13 +669,6 @@ bool cortexa_attach(target_s *target)
/* Clear any pending fault condition */
target_check_error(target);

/* Enable halting debug mode */
uint32_t dbgdscr = cortex_dbg_read32(target, CORTEXAR_DBG_DSCR);
dbgdscr |= CORTEXAR_DBG_DSCR_ITR_ENABLE | CORTEXAR_DBG_DSCR_ITR_ENABLE;
dbgdscr &= ~DBGDSCR_EXTDCCMODE_MASK;
cortex_dbg_write32(target, CORTEXAR_DBG_DSCR, dbgdscr);
DEBUG_INFO("DBGDSCR = 0x%08" PRIx32 "\n", dbgdscr);

target_halt_request(target);
size_t tries = 10;
while (!platform_nrst_get_val() && !target_halt_poll(target, NULL) && --tries)
Expand Down