From 16b4b8cf5453660c849546ebf8a0c3a5a082329e Mon Sep 17 00:00:00 2001 From: David Brownell Date: Thu, 5 Nov 2009 01:04:08 -0800 Subject: [PATCH] Cortex-M3: expose most DWT registers Expose most DWT registers via Tcl; there are a few more, but those are mostly for profiling along with the ITM. Having this set available enables operations which aren't possible with just the standard watchpoint operations. The cycle counter may be interesting. Turn it on after reset by setting the LSB of the dwt_ctrl register, and it counts CPU clocks. You can program the comparator 0 watchpoint to trigger on a given cycle count, rather than a data address. Likewise, comparator 1 may be able to match data values given address matches from one or two other comparators. (Not all hardware supports this capability though; try it. That is something the standard watchpoint methods should eventually handle, for the single address case.) Minor cleanup: remove needless functional indirection for exposing the v7m architctural registers. Signed-off-by: David Brownell --- src/target/cortex_m3.c | 163 +++++++++++++++++++++++++++++++++++------ src/target/cortex_m3.h | 2 + 2 files changed, 144 insertions(+), 21 deletions(-) diff --git a/src/target/cortex_m3.c b/src/target/cortex_m3.c index d8a28796a2..eb37add3d2 100644 --- a/src/target/cortex_m3.c +++ b/src/target/cortex_m3.c @@ -1480,22 +1480,157 @@ static int cortex_m3_bulk_write_memory(target_t *target, uint32_t address, return cortex_m3_write_memory(target, address, 4, count, buffer); } -static void cortex_m3_build_reg_cache(target_t *target) +static int cortex_m3_init_target(struct command_context_s *cmd_ctx, + struct target_s *target) { armv7m_build_reg_cache(target); + return ERROR_OK; } -static int cortex_m3_init_target(struct command_context_s *cmd_ctx, - struct target_s *target) +/* REVISIT cache valid/dirty bits are unmaintained. We could set "valid" + * on r/w if the core is not running, and clear on resume or reset ... or + * at least, in a post_restore_context() method. + */ + +struct dwt_reg_state { + struct target_s *target; + uint32_t addr; + uint32_t value; /* scratch/cache */ +}; + +static int cortex_m3_dwt_get_reg(struct reg_s *reg) { - cortex_m3_build_reg_cache(target); - return ERROR_OK; + struct dwt_reg_state *state = reg->arch_info; + + return target_read_u32(state->target, state->addr, &state->value); +} + +static int cortex_m3_dwt_set_reg(struct reg_s *reg, uint8_t *buf) +{ + struct dwt_reg_state *state = reg->arch_info; + + return target_write_u32(state->target, state->addr, + buf_get_u32(buf, 0, reg->size)); +} + +struct dwt_reg { + uint32_t addr; + char *name; + unsigned size; +}; + +static struct dwt_reg dwt_base_regs[] = { + { DWT_CTRL, "dwt_ctrl", 32, }, + { DWT_CYCCNT, "dwt_cyccnt", 32, }, + /* plus some 8 bit counters, useful for profiling with TPIU */ +}; + +static struct dwt_reg dwt_comp[] = { +#define DWT_COMPARATOR(i) \ + { DWT_COMP0 + 0x10 * (i), "dwt_" #i "_comp", 32, }, \ + { DWT_MASK0 + 0x10 * (i), "dwt_" #i "_mask", 4, }, \ + { DWT_FUNCTION0 + 0x10 * (i), "dwt_" #i "_function", 32, } + DWT_COMPARATOR(0), + DWT_COMPARATOR(1), + DWT_COMPARATOR(2), + DWT_COMPARATOR(3), +#undef DWT_COMPARATOR +}; + +static int dwt_reg_type = -1; + +static void +cortex_m3_dwt_addreg(struct target_s *t, struct reg_s *r, struct dwt_reg *d) +{ + struct dwt_reg_state *state; + + state = calloc(1, sizeof *state); + if (!state) + return; + state->addr = d->addr; + state->target = t; + + r->name = d->name; + r->size = d->size; + r->value = &state->value; + r->arch_info = state; + r->arch_type = dwt_reg_type; +} + +static void +cortex_m3_dwt_setup(cortex_m3_common_t *cm3, struct target_s *target) +{ + uint32_t dwtcr; + struct reg_cache_s *cache; + cortex_m3_dwt_comparator_t *comparator; + int reg, i; + + target_read_u32(target, DWT_CTRL, &dwtcr); + if (!dwtcr) { + LOG_DEBUG("no DWT"); + return; + } + + if (dwt_reg_type < 0) + dwt_reg_type = register_reg_arch_type(cortex_m3_dwt_get_reg, + cortex_m3_dwt_set_reg); + + cm3->dwt_num_comp = (dwtcr >> 28) & 0xF; + cm3->dwt_comp_available = cm3->dwt_num_comp; + cm3->dwt_comparator_list = calloc(cm3->dwt_num_comp, + sizeof(cortex_m3_dwt_comparator_t)); + if (!cm3->dwt_comparator_list) { +fail0: + cm3->dwt_num_comp = 0; + LOG_ERROR("out of mem"); + return; + } + + cache = calloc(1, sizeof *cache); + if (!cache) { +fail1: + free(cm3->dwt_comparator_list); + goto fail0; + } + cache->name = "cortex-m3 dwt registers"; + cache->num_regs = 2 + cm3->dwt_num_comp * 3; + cache->reg_list = calloc(cache->num_regs, sizeof *cache->reg_list); + if (!cache->reg_list) { + free(cache); + goto fail1; + } + + for (reg = 0; reg < 2; reg++) + cortex_m3_dwt_addreg(target, cache->reg_list + reg, + dwt_base_regs + reg); + + comparator = cm3->dwt_comparator_list; + for (i = 0; i < cm3->dwt_num_comp; i++, comparator++) { + int j; + + comparator->dwt_comparator_address = DWT_COMP0 + 0x10 * i; + for (j = 0; j < 3; j++, reg++) + cortex_m3_dwt_addreg(target, cache->reg_list + reg, + dwt_comp + 3 * i + j); + } + + *register_get_last_cache_p(&target->reg_cache) = cache; + cm3->dwt_cache = cache; + + LOG_INFO("DWT dwtcr 0x%" PRIx32 ", comp %d, watch%s", + dwtcr, cm3->dwt_num_comp, + (dwtcr & (0xf << 24)) ? " only" : "/trigger"); + + /* REVISIT: if num_comp > 1, check whether comparator #1 can + * implement single-address data value watchpoints ... so we + * won't need to check it later, when asked to set one up. + */ } static int cortex_m3_examine(struct target_s *target) { int retval; - uint32_t cpuid, fpcr, dwtcr; + uint32_t cpuid, fpcr; int i; /* get pointers to arch-specific information */ @@ -1537,21 +1672,7 @@ static int cortex_m3_examine(struct target_s *target) LOG_DEBUG("FPB fpcr 0x%" PRIx32 ", numcode %i, numlit %i", fpcr, cortex_m3->fp_num_code, cortex_m3->fp_num_lit); /* Setup DWT */ - target_read_u32(target, DWT_CTRL, &dwtcr); - cortex_m3->dwt_num_comp = (dwtcr >> 28) & 0xF; - cortex_m3->dwt_comp_available = cortex_m3->dwt_num_comp; - cortex_m3->dwt_comparator_list = calloc( - cortex_m3->dwt_num_comp, - sizeof(cortex_m3_dwt_comparator_t)); - for (i = 0; i < cortex_m3->dwt_num_comp; i++) - { - cortex_m3->dwt_comparator_list[i] - .dwt_comparator_address = DWT_COMP0 + 0x10 * i; - } - if (cortex_m3->dwt_num_comp) - LOG_DEBUG("DWT dwtcr 0x%" PRIx32 ", comp %d, watch%s", - dwtcr, cortex_m3->dwt_num_comp, - (dwtcr & (0xf << 24)) ? " only" : "/trigger"); + cortex_m3_dwt_setup(cortex_m3, target); } return ERROR_OK; diff --git a/src/target/cortex_m3.h b/src/target/cortex_m3.h index a7074d36c9..1dd724c8c8 100644 --- a/src/target/cortex_m3.h +++ b/src/target/cortex_m3.h @@ -45,6 +45,7 @@ #define DCRSR_WnR (1 << 16) #define DWT_CTRL 0xE0001000 +#define DWT_CYCCNT 0xE0001004 #define DWT_COMP0 0xE0001020 #define DWT_MASK0 0xE0001024 #define DWT_FUNCTION0 0xE0001028 @@ -157,6 +158,7 @@ typedef struct cortex_m3_common_s int dwt_num_comp; int dwt_comp_available; cortex_m3_dwt_comparator_t *dwt_comparator_list; + struct reg_cache_s *dwt_cache; armv7m_common_t armv7m; void *arch_info; -- 2.30.2