jtag/drivers/stlink: allow to reconnect seamlessly after polling failure

If the communication with the target was failing (either because of an
intermittent connection or the target was rebooted), this is needed to
reestablish operational state.

Reported-by: Tim Sander <tim@krieglstein.org>
Tested-by: Tim Sander <tim@krieglstein.org>
Change-Id: I91ea2e2b2b5ef8eb27dfe9bae95ef2a919f67e4e
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/2152
Tested-by: jenkins
Reviewed-by: Tim Sander <tim@krieglstein.org>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

diff --git a/src/jtag/drivers/stlink_usb.c b/src/jtag/drivers/stlink_usb.c
index b4dc0de3c9e646d665d34473de32b82ed37ca755..5574a40bae49ec9e1a377908bbf2963c26158e67 100644 (file)
--- a/src/jtag/drivers/stlink_usb.c
+++ b/src/jtag/drivers/stlink_usb.c
@@ -126,6 +126,9 @@ struct stlink_usb_handle_s {
                /** trace module clock prescaler */
                uint32_t prescale;
        } trace;
+       /** reconnect is needed next time we try to query the
+        * status */
+       bool reconnect_pending;
 };
 
 #define STLINK_DEBUG_ERR_OK            0x80
@@ -618,6 +621,20 @@ static int stlink_usb_mode_leave(void *handle, enum stlink_mode type)
 
 static int stlink_usb_assert_srst(void *handle, int srst);
 
+static enum stlink_mode stlink_get_mode(enum hl_transports t)
+{
+       switch (t) {
+       case HL_TRANSPORT_SWD:
+               return STLINK_MODE_DEBUG_SWD;
+       case HL_TRANSPORT_JTAG:
+               return STLINK_MODE_DEBUG_JTAG;
+       case HL_TRANSPORT_SWIM:
+               return STLINK_MODE_DEBUG_SWIM;
+       default:
+               return STLINK_MODE_UNKNOWN;
+       }
+}
+
 /** */
 static int stlink_usb_init_mode(void *handle, bool connect_under_reset)
 {
@@ -691,20 +708,7 @@ static int stlink_usb_init_mode(void *handle, bool connect_under_reset)
        LOG_DEBUG("MODE: 0x%02X", mode);
 
        /* set selected mode */
-       switch (h->transport) {
-               case HL_TRANSPORT_SWD:
-                       emode = STLINK_MODE_DEBUG_SWD;
-                       break;
-               case HL_TRANSPORT_JTAG:
-                       emode = STLINK_MODE_DEBUG_JTAG;
-                       break;
-               case HL_TRANSPORT_SWIM:
-                       emode = STLINK_MODE_DEBUG_SWIM;
-                       break;
-               default:
-                       emode = STLINK_MODE_UNKNOWN;
-                       break;
-       }
+       emode = stlink_get_mode(h->transport);
 
        if (emode == STLINK_MODE_UNKNOWN) {
                LOG_ERROR("selected mode (transport) not supported");
@@ -877,8 +881,22 @@ static enum target_state stlink_usb_state(void *handle)
 
        assert(handle != NULL);
 
-       if (h->jtag_api == STLINK_JTAG_API_V2)
-               return stlink_usb_v2_get_status(handle);
+       if (h->reconnect_pending) {
+               LOG_INFO("Previous state query failed, trying to reconnect");
+               res = stlink_usb_mode_enter(handle, stlink_get_mode(h->transport));
+
+               if (res != ERROR_OK)
+                       return TARGET_UNKNOWN;
+
+               h->reconnect_pending = false;
+       }
+
+       if (h->jtag_api == STLINK_JTAG_API_V2) {
+               res = stlink_usb_v2_get_status(handle);
+               if (res == TARGET_UNKNOWN)
+                       h->reconnect_pending = true;
+               return res;
+       }
 
        stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
@@ -895,6 +913,8 @@ static enum target_state stlink_usb_state(void *handle)
        if (h->databuf[0] == STLINK_CORE_HALTED)
                return TARGET_HALTED;
 
+       h->reconnect_pending = true;
+
        return TARGET_UNKNOWN;
 }