From 31af18e9d1807d442885d0254ff5b13a66ea3a65 Mon Sep 17 00:00:00 2001 From: Tomas Vanek Date: Sat, 17 Feb 2024 13:14:01 +0100 Subject: [PATCH] jtag/drivers/bitbang: limit SWD WAIT retries by timeout The bitbang driver kept retrying a SWD command as long as the debugged device had been responding by SWD WAIT. If the DP stalled in WAIT permanently, OpenOCD hanged. Check 0.5 sec timeout in WAIT retry loop. While on it insert a short alive_sleep() if the command is retried 20 or more times. Signed-off-by: Tomas Vanek Change-Id: I744e56e21a5a2dc2c4494cc0d7bbcb4be14ddb23 Reviewed-on: https://review.openocd.org/c/openocd/+/8153 Reviewed-by: Antonio Borneo Tested-by: jenkins --- src/jtag/drivers/bitbang.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/src/jtag/drivers/bitbang.c b/src/jtag/drivers/bitbang.c index f0236848b..3d839e65d 100644 --- a/src/jtag/drivers/bitbang.c +++ b/src/jtag/drivers/bitbang.c @@ -20,6 +20,11 @@ #include #include +#include + +/* Timeout for retrying on SWD WAIT in msec */ +#define SWD_WAIT_TIMEOUT 500 + /** * Function bitbang_stableclocks * issues a number of clock cycles while staying in a stable state. @@ -474,6 +479,7 @@ static void bitbang_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay return; } + int64_t timeout = timeval_ms() + SWD_WAIT_TIMEOUT; for (unsigned int retry = 0;; retry++) { uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)]; @@ -496,8 +502,11 @@ static void bitbang_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay (cmd & SWD_CMD_A32) >> 1, data); - if (ack == SWD_ACK_WAIT) { + if (ack == SWD_ACK_WAIT && timeval_ms() <= timeout) { swd_clear_sticky_errors(); + if (retry > 20) + alive_sleep(1); + continue; } if (retry > 1) @@ -530,6 +539,8 @@ static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay return; } + int64_t timeout = timeval_ms() + SWD_WAIT_TIMEOUT; + /* Devices do not reply to DP_TARGETSEL write cmd, ignore received ack */ bool check_ack = swd_cmd_returns_ack(cmd); @@ -569,8 +580,11 @@ static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay (cmd & SWD_CMD_A32) >> 1, buf_get_u32(trn_ack_data_parity_trn, 1 + 3 + 1, 32)); - if (check_ack && ack == SWD_ACK_WAIT) { + if (check_ack && ack == SWD_ACK_WAIT && timeval_ms() <= timeout) { swd_clear_sticky_errors(); + if (retry > 20) + alive_sleep(1); + continue; }