[PATCH]: f0e8220098 jtag/drivers/bitbang: limit SWD WAIT retries by timeout

[gerrit]

This is an automated email from Gerrit.

"Tomas Vanek <van...@fbl.cz>" just uploaded a new patch set to Gerrit, which 
you can find at https://review.openocd.org/c/openocd/+/8153

-- gerrit

commit f0e822009838e55d6ddb081cf84f97dbd0ad5ea2
Author: Tomas Vanek <van...@fbl.cz>
Date:   Sat Feb 17 13:14:01 2024 +0100

    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 <van...@fbl.cz>
    Change-Id: I744e56e21a5a2dc2c4494cc0d7bbcb4be14ddb23

diff --git a/src/jtag/drivers/bitbang.c b/src/jtag/drivers/bitbang.c
index f0236848b3..3d839e65de 100644
--- a/src/jtag/drivers/bitbang.c
+++ b/src/jtag/drivers/bitbang.c
@@ -20,6 +20,11 @@
 #include <jtag/interface.h>
 #include <jtag/commands.h>
 
+#include <helper/time_support.h>
+
+/* 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;
                }
 

--