From caa16981364d747c1c71edaf156e8a4faa83b02b Mon Sep 17 00:00:00 2001 From: Andreas Fritiofson Date: Mon, 8 Nov 2021 18:09:56 +0100 Subject: [PATCH] cortex_m: Restore fast register reads if no polling is needed If the target is in a state where S_REGRDY polling is necessary (slow clock, low power state...?), OpenOCD will continue to use the slow path even if the condition is temporary and the target at a later point would be capable of fast reads again. Revert to fast reads if a full register dump can be made without need for polling any of the registers; presumably it will succeed the next time too. Change-Id: I557f0d90b7ce6f9d81aa409b6400fc9c83d16008 Signed-off-by: Andreas Fritiofson Reviewed-on: https://review.openocd.org/c/openocd/+/6678 Tested-by: jenkins Reviewed-by: Antonio Borneo Reviewed-by: Tomas Vanek --- src/target/cortex_m.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c index 82d5eff800..721cf0a246 100644 --- a/src/target/cortex_m.c +++ b/src/target/cortex_m.c @@ -183,6 +183,7 @@ static int cortex_m_load_core_reg_u32(struct target *target, cortex_m_cumulate_dhcsr_sticky(cortex_m, cortex_m->dcb_dhcsr); if (cortex_m->dcb_dhcsr & S_REGRDY) break; + cortex_m->slow_register_read = true; /* Polling (still) needed. */ if (timeval_ms() > then + DHCSR_S_REGRDY_TIMEOUT) { LOG_ERROR("Timeout waiting for DCRDR transfer ready"); return ERROR_TIMEOUT_REACHED; @@ -204,9 +205,14 @@ static int cortex_m_load_core_reg_u32(struct target *target, static int cortex_m_slow_read_all_regs(struct target *target) { + struct cortex_m_common *cortex_m = target_to_cm(target); struct armv7m_common *armv7m = target_to_armv7m(target); const unsigned int num_regs = armv7m->arm.core_cache->num_regs; + /* Opportunistically restore fast read, it'll revert to slow + * if any register needed polling in cortex_m_load_core_reg_u32(). */ + cortex_m->slow_register_read = false; + for (unsigned int reg_id = 0; reg_id < num_regs; reg_id++) { struct reg *r = &armv7m->arm.core_cache->reg_list[reg_id]; if (r->exist) { @@ -215,6 +221,10 @@ static int cortex_m_slow_read_all_regs(struct target *target) return retval; } } + + if (!cortex_m->slow_register_read) + LOG_DEBUG("Switching back to fast register reads"); + return ERROR_OK; } -- 2.30.2