From 34bbbe796178a85305dcd2ffb3dae02b6a372e55 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Sun, 20 Dec 2009 16:33:00 -0800 Subject: Cortex-M3: cleanup Misc: - Introduce some "struct reg" temporaries, for clarity - Shorten lines - Add some missing whitespace - Clean up comments - Add notes about some fault handling issues - Most of these errata workarounds are for *OLD* chip revisions Signed-off-by: David Brownell --- src/target/cortex_m3.c | 156 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 111 insertions(+), 45 deletions(-) (limited to 'src') diff --git a/src/target/cortex_m3.c b/src/target/cortex_m3.c index 6bc427a4..edf9b6f0 100644 --- a/src/target/cortex_m3.c +++ b/src/target/cortex_m3.c @@ -42,6 +42,10 @@ /* NOTE: most of this should work fine for the Cortex-M1 and * Cortex-M0 cores too, although they're ARMv6-M not ARMv7-M. + * + * Although there are some workarounds for errata seen only in r0p0 + * silicon, such old parts are hard to find and thus not much tested + * any longer. */ @@ -138,6 +142,7 @@ static int cortex_m3_clear_halt(struct target *target) /* Read Debug Fault Status Register */ mem_ap_read_atomic_u32(swjdp, NVIC_DFSR, &cortex_m3->nvic_dfsr); + /* Clear Debug Fault Status */ mem_ap_write_atomic_u32(swjdp, NVIC_DFSR, cortex_m3->nvic_dfsr); LOG_DEBUG(" NVIC_DFSR 0x%" PRIx32 "", cortex_m3->nvic_dfsr); @@ -154,10 +159,15 @@ static int cortex_m3_single_step_core(struct target *target) /* backup dhcsr reg */ dhcsr_save = cortex_m3->dcb_dhcsr; - /* mask interrupts if not done already */ + /* Mask interrupts before clearing halt, if done already. This avoids + * Erratum 377497 (fixed in r1p0) where setting MASKINTS while clearing + * HALT can put the core into an unknown state. + */ if (!(cortex_m3->dcb_dhcsr & C_MASKINTS)) - mem_ap_write_atomic_u32(swjdp, DCB_DHCSR, DBGKEY | C_MASKINTS | C_HALT | C_DEBUGEN); - mem_ap_write_atomic_u32(swjdp, DCB_DHCSR, DBGKEY | C_MASKINTS | C_STEP | C_DEBUGEN); + mem_ap_write_atomic_u32(swjdp, DCB_DHCSR, + DBGKEY | C_MASKINTS | C_HALT | C_DEBUGEN); + mem_ap_write_atomic_u32(swjdp, DCB_DHCSR, + DBGKEY | C_MASKINTS | C_STEP | C_DEBUGEN); LOG_DEBUG(" "); /* restore dhcsr reg */ @@ -176,10 +186,11 @@ static int cortex_m3_endreset_event(struct target *target) struct cortex_m3_fp_comparator *fp_list = cortex_m3->fp_comparator_list; struct cortex_m3_dwt_comparator *dwt_list = cortex_m3->dwt_comparator_list; + /* FIXME handling of DEMCR clobbers vector_catch config ... */ mem_ap_read_atomic_u32(swjdp, DCB_DEMCR, &dcb_demcr); LOG_DEBUG("DCB_DEMCR = 0x%8.8" PRIx32 "",dcb_demcr); - /* this regsiter is used for emulated dcc channel */ + /* this register is used for emulated dcc channel */ mem_ap_write_u32(swjdp, DCB_DCRDR, 0); /* Enable debug requests */ @@ -190,11 +201,26 @@ static int cortex_m3_endreset_event(struct target *target) /* clear any interrupt masking */ cortex_m3_write_debug_halt_mask(target, 0, C_MASKINTS); - /* Enable trace and dwt */ + /* Enable trace and DWT; trap hard and bus faults. + * + * REVISIT why trap those two? And why trash the vector_catch + * config, instead of preserving it? Catching HARDERR and BUSERR + * will interfere with code that handles those itself... + */ mem_ap_write_u32(swjdp, DCB_DEMCR, TRCENA | VC_HARDERR | VC_BUSERR); - /* Monitor bus faults */ + + /* Monitor bus faults as such (instead of as generic HARDERR), but + * leave memory management and usage faults disabled. + * + * REVISIT setting BUSFAULTENA interferes with code which relies + * on the default setting. Why do it? + */ mem_ap_write_u32(swjdp, NVIC_SHCSR, SHCSR_BUSFAULTENA); + /* Paranoia: evidently some (early?) chips don't preserve all the + * debug state (including FBP, DWT, etc) across reset... + */ + /* Enable FPB */ target_write_u32(target, FP_CTRL, 3); cortex_m3->fpb_enabled = 1; @@ -308,6 +334,7 @@ static int cortex_m3_debug_entry(struct target *target) struct cortex_m3_common *cortex_m3 = target_to_cm3(target); struct armv7m_common *armv7m = &cortex_m3->armv7m; struct swjdp_common *swjdp = &armv7m->swjdp_info; + struct reg *r; LOG_DEBUG(" "); @@ -327,7 +354,8 @@ static int cortex_m3_debug_entry(struct target *target) armv7m->read_core_reg(target, i); } - xPSR = buf_get_u32(armv7m->core_cache->reg_list[ARMV7M_xPSR].value, 0, 32); + r = armv7m->core_cache->reg_list + ARMV7M_xPSR; + xPSR = buf_get_u32(r->value, 0, 32); #ifdef ARMV7_GDB_HACKS /* FIXME this breaks on scan chains with more than one Cortex-M3. @@ -336,14 +364,14 @@ static int cortex_m3_debug_entry(struct target *target) /* copy real xpsr reg for gdb, setting thumb bit */ buf_set_u32(armv7m_gdb_dummy_cpsr_value, 0, 32, xPSR); buf_set_u32(armv7m_gdb_dummy_cpsr_value, 5, 1, 1); - armv7m_gdb_dummy_cpsr_reg.valid = armv7m->core_cache->reg_list[ARMV7M_xPSR].valid; - armv7m_gdb_dummy_cpsr_reg.dirty = armv7m->core_cache->reg_list[ARMV7M_xPSR].dirty; + armv7m_gdb_dummy_cpsr_reg.valid = r->valid; + armv7m_gdb_dummy_cpsr_reg.dirty = r->dirty; #endif /* For IT instructions xPSR must be reloaded on resume and clear on debug exec */ if (xPSR & 0xf00) { - armv7m->core_cache->reg_list[ARMV7M_xPSR].dirty = armv7m->core_cache->reg_list[ARMV7M_xPSR].valid; + r->dirty = r->valid; cortex_m3_store_core_reg_u32(target, ARMV7M_REGISTER_CORE_GP, 16, xPSR &~ 0xff); } @@ -355,7 +383,8 @@ static int cortex_m3_debug_entry(struct target *target) } else { - armv7m->core_mode = buf_get_u32(armv7m->core_cache->reg_list[ARMV7M_CONTROL].value, 0, 1); + armv7m->core_mode = buf_get_u32(armv7m->core_cache + ->reg_list[ARMV7M_CONTROL].value, 0, 1); armv7m->exception_number = 0; } @@ -404,8 +433,11 @@ static int cortex_m3_poll(struct target *target) if (target->state == TARGET_RESET) { - /* Cannot switch context while running so endreset is called with target->state == TARGET_RESET */ - LOG_DEBUG("Exit from reset with dcb_dhcsr 0x%" PRIx32 "", cortex_m3->dcb_dhcsr); + /* Cannot switch context while running so endreset is + * called with target->state == TARGET_RESET + */ + LOG_DEBUG("Exit from reset with dcb_dhcsr 0x%" PRIx32, + cortex_m3->dcb_dhcsr); cortex_m3_endreset_event(target); target->state = TARGET_RUNNING; prev_target_state = TARGET_RUNNING; @@ -498,11 +530,13 @@ static int cortex_m3_soft_reset_halt(struct target *target) uint32_t dcb_dhcsr = 0; int retval, timeout = 0; - /* Enter debug state on reset, cf. end_reset_event() */ - mem_ap_write_u32(swjdp, DCB_DEMCR, TRCENA | VC_HARDERR | VC_BUSERR | VC_CORERESET); + /* Enter debug state on reset; see end_reset_event() */ + mem_ap_write_u32(swjdp, DCB_DEMCR, + TRCENA | VC_HARDERR | VC_BUSERR | VC_CORERESET); - /* Request a reset */ - mem_ap_write_atomic_u32(swjdp, NVIC_AIRCR, AIRCR_VECTKEY | AIRCR_VECTRESET); + /* Request a core-only reset */ + mem_ap_write_atomic_u32(swjdp, NVIC_AIRCR, + AIRCR_VECTKEY | AIRCR_VECTRESET); target->state = TARGET_RESET; /* registers are now invalid */ @@ -513,15 +547,23 @@ static int cortex_m3_soft_reset_halt(struct target *target) retval = mem_ap_read_atomic_u32(swjdp, DCB_DHCSR, &dcb_dhcsr); if (retval == ERROR_OK) { - mem_ap_read_atomic_u32(swjdp, NVIC_DFSR, &cortex_m3->nvic_dfsr); - if ((dcb_dhcsr & S_HALT) && (cortex_m3->nvic_dfsr & DFSR_VCATCH)) + mem_ap_read_atomic_u32(swjdp, NVIC_DFSR, + &cortex_m3->nvic_dfsr); + if ((dcb_dhcsr & S_HALT) + && (cortex_m3->nvic_dfsr & DFSR_VCATCH)) { - LOG_DEBUG("system reset-halted, dcb_dhcsr 0x%" PRIx32 ", nvic_dfsr 0x%" PRIx32 "", dcb_dhcsr, cortex_m3->nvic_dfsr); + LOG_DEBUG("system reset-halted, DHCSR 0x%08x, " + "DFSR 0x%08x", + (unsigned) dcb_dhcsr, + (unsigned) cortex_m3->nvic_dfsr); cortex_m3_poll(target); + /* FIXME restore user's vector catch config */ return ERROR_OK; } else - LOG_DEBUG("waiting for system reset-halt, dcb_dhcsr 0x%" PRIx32 ", %i ms", dcb_dhcsr, timeout); + LOG_DEBUG("waiting for system reset-halt, " + "DHCSR 0x%08x, %d ms", + (unsigned) dcb_dhcsr, timeout); } timeout++; alive_sleep(1); @@ -549,6 +591,7 @@ static int cortex_m3_resume(struct target *target, int current, struct armv7m_common *armv7m = target_to_armv7m(target); struct breakpoint *breakpoint = NULL; uint32_t resume_pc; + struct reg *r; if (target->state != TARGET_HALTED) { @@ -565,30 +608,40 @@ static int cortex_m3_resume(struct target *target, int current, if (debug_execution) { + r = armv7m->core_cache->reg_list + ARMV7M_PRIMASK; + /* Disable interrupts */ - /* We disable interrupts in the PRIMASK register instead of masking with C_MASKINTS, - * This is probably the same issue as Cortex-M3 Errata 377493: - * C_MASKINTS in parallel with disabled interrupts can cause local faults to not be taken. */ - buf_set_u32(armv7m->core_cache->reg_list[ARMV7M_PRIMASK].value, 0, 32, 1); - armv7m->core_cache->reg_list[ARMV7M_PRIMASK].dirty = 1; - armv7m->core_cache->reg_list[ARMV7M_PRIMASK].valid = 1; + /* We disable interrupts in the PRIMASK register instead of + * masking with C_MASKINTS. This is probably the same issue + * as Cortex-M3 Erratum 377493 (fixed in r1p0): C_MASKINTS + * in parallel with disabled interrupts can cause local faults + * to not be taken. + * + * REVISIT this clearly breaks non-debug execution, since the + * PRIMASK register state isn't saved/restored... workaround + * by never resuming app code after debug execution. + */ + buf_set_u32(r->value, 0, 1, 1); + r->dirty = true; + r->valid = true; /* Make sure we are in Thumb mode */ - buf_set_u32(armv7m->core_cache->reg_list[ARMV7M_xPSR].value, 0, 32, - buf_get_u32(armv7m->core_cache->reg_list[ARMV7M_xPSR].value, 0, 32) | (1 << 24)); - armv7m->core_cache->reg_list[ARMV7M_xPSR].dirty = 1; - armv7m->core_cache->reg_list[ARMV7M_xPSR].valid = 1; + r = armv7m->core_cache->reg_list + ARMV7M_xPSR; + buf_set_u32(r->value, 24, 1, 1); + r->dirty = true; + r->valid = true; } /* current = 1: continue on current pc, otherwise continue at
*/ + r = armv7m->core_cache->reg_list + 15; if (!current) { - buf_set_u32(armv7m->core_cache->reg_list[15].value, 0, 32, address); - armv7m->core_cache->reg_list[15].dirty = 1; - armv7m->core_cache->reg_list[15].valid = 1; + buf_set_u32(r->value, 0, 32, address); + r->dirty = true; + r->valid = true; } - resume_pc = buf_get_u32(armv7m->core_cache->reg_list[15].value, 0, 32); + resume_pc = buf_get_u32(r->value, 0, 32); armv7m_restore_context(target); @@ -639,6 +692,7 @@ static int cortex_m3_step(struct target *target, int current, struct armv7m_common *armv7m = &cortex_m3->armv7m; struct swjdp_common *swjdp = &armv7m->swjdp_info; struct breakpoint *breakpoint = NULL; + struct reg *pc = armv7m->core_cache->reg_list + 15; if (target->state != TARGET_HALTED) { @@ -648,13 +702,12 @@ static int cortex_m3_step(struct target *target, int current, /* current = 1: continue on current pc, otherwise continue at
*/ if (!current) - buf_set_u32(cortex_m3->armv7m.core_cache->reg_list[15].value, - 0, 32, address); + buf_set_u32(pc->value, 0, 32, address); /* the front-end may request us not to handle breakpoints */ if (handle_breakpoints) { - breakpoint = breakpoint_find(target, buf_get_u32(armv7m - ->core_cache->reg_list[15].value, 0, 32)); + breakpoint = breakpoint_find(target, + buf_get_u32(pc->value, 0, 32)); if (breakpoint) cortex_m3_unset_breakpoint(target, breakpoint); } @@ -675,12 +728,16 @@ static int cortex_m3_step(struct target *target, int current, if (breakpoint) cortex_m3_set_breakpoint(target, breakpoint); - LOG_DEBUG("target stepped dcb_dhcsr = 0x%" PRIx32 " nvic_icsr = 0x%" PRIx32 "", cortex_m3->dcb_dhcsr, cortex_m3->nvic_icsr); + LOG_DEBUG("target stepped dcb_dhcsr = 0x%" PRIx32 + " nvic_icsr = 0x%" PRIx32, + cortex_m3->dcb_dhcsr, cortex_m3->nvic_icsr); cortex_m3_debug_entry(target); target_call_event_callbacks(target, TARGET_EVENT_HALTED); - LOG_DEBUG("target stepped dcb_dhcsr = 0x%" PRIx32 " nvic_icsr = 0x%" PRIx32 "", cortex_m3->dcb_dhcsr, cortex_m3->nvic_icsr); + LOG_DEBUG("target stepped dcb_dhcsr = 0x%" PRIx32 + " nvic_icsr = 0x%" PRIx32, + cortex_m3->dcb_dhcsr, cortex_m3->nvic_icsr); return ERROR_OK; } @@ -714,7 +771,8 @@ static int cortex_m3_assert_reset(struct target *target) { /* Set/Clear C_MASKINTS in a separate operation */ if (cortex_m3->dcb_dhcsr & C_MASKINTS) - mem_ap_write_atomic_u32(swjdp, DCB_DHCSR, DBGKEY | C_DEBUGEN | C_HALT); + mem_ap_write_atomic_u32(swjdp, DCB_DHCSR, + DBGKEY | C_DEBUGEN | C_HALT); /* clear any debug flags before resuming */ cortex_m3_clear_halt(target); @@ -723,12 +781,14 @@ static int cortex_m3_assert_reset(struct target *target) cortex_m3_write_debug_halt_mask(target, 0, C_HALT); /* Enter debug state on reset, cf. end_reset_event() */ - mem_ap_write_u32(swjdp, DCB_DEMCR, TRCENA | VC_HARDERR | VC_BUSERR); + mem_ap_write_u32(swjdp, DCB_DEMCR, + TRCENA | VC_HARDERR | VC_BUSERR); } else { /* Enter debug state on reset, cf. end_reset_event() */ - mem_ap_write_atomic_u32(swjdp, DCB_DEMCR, TRCENA | VC_HARDERR | VC_BUSERR | VC_CORERESET); + mem_ap_write_atomic_u32(swjdp, DCB_DEMCR, + TRCENA | VC_HARDERR | VC_BUSERR | VC_CORERESET); } /* @@ -1311,8 +1371,11 @@ static int cortex_m3_store_core_reg_u32(struct target *target, retval = cortexm3_dap_write_coreregister_u32(swjdp, value, num); if (retval != ERROR_OK) { + struct reg *r; + LOG_ERROR("JTAG failure %i", retval); - armv7m->core_cache->reg_list[num].dirty = armv7m->core_cache->reg_list[num].valid; + r = armv7m->core_cache->reg_list + num; + r->dirty = r->valid; return ERROR_JTAG_DEVICE_ERROR; } LOG_DEBUG("write core reg %i value 0x%" PRIx32 "", (int)num, value); @@ -1455,6 +1518,9 @@ struct dwt_reg { static struct dwt_reg dwt_base_regs[] = { { DWT_CTRL, "dwt_ctrl", 32, }, + /* NOTE that Erratum 532314 (fixed r2p0) affects CYCCNT: it wrongly + * increments while the core is asleep. + */ { DWT_CYCCNT, "dwt_cyccnt", 32, }, /* plus some 8 bit counters, useful for profiling with TPIU */ }; -- cgit v1.2.3