X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=src%2Fstlink-usb.c;h=98654129eccdca57b5a20ebaca2b5d525f48d873;hb=refs%2Fheads%2Fdebian;hp=4a62d9dd5ff12d4f27e0b63df13c4f685d2ef0b4;hpb=3c3b02e83e358edee5e704eb61b96d7d1561ff42;p=fw%2Fstlink

diff --git a/src/stlink-usb.c b/src/stlink-usb.c
index 4a62d9d..9865412 100644
--- a/src/stlink-usb.c
+++ b/src/stlink-usb.c
@@ -5,37 +5,21 @@
 #include <sys/time.h>
 #include <sys/types.h>
 #include <libusb.h>
+#include <errno.h>
+#include <unistd.h>
 
 #include "stlink-common.h"
 #include "stlink-usb.h"
-#include "uglylogging.h"
-
-/* code from bsd timersub.h
-http://www.gnu-darwin.org/www001/src/ports/net/libevnet/work/libevnet-0.3.8/libnostd/bsd/sys/time/timersub.h.html
-*/
-#if !defined timersub
-#define	timersub(a, b, r) do {					\
-    (r)->tv_sec	= (a)->tv_sec - (b)->tv_sec;		\
-    (r)->tv_usec	= (a)->tv_usec - (b)->tv_usec;		\
-    if ((r)->tv_usec < 0) {					\
-        --(r)->tv_sec;					\
-        (r)->tv_usec += 1000000;			\
-    }							\
-} while (0)
-#endif
 
 enum SCSI_Generic_Direction {SG_DXFER_TO_DEV=0, SG_DXFER_FROM_DEV=0x80};
 
 void _stlink_usb_close(stlink_t* sl) {
+    if (!sl)
+        return;
+
     struct stlink_libusb * const handle = sl->backend_data;
     // maybe we couldn't even get the usb device?
     if (handle != NULL) {
-        if (handle->req_trans != NULL)
-            libusb_free_transfer(handle->req_trans);
-
-        if (handle->rep_trans != NULL)
-            libusb_free_transfer(handle->rep_trans);
-
         if (handle->usb_handle != NULL) {
             libusb_close(handle->usb_handle);
         }
@@ -45,111 +29,42 @@ void _stlink_usb_close(stlink_t* sl) {
     }
 }
 
-
-struct trans_ctx {
-#define TRANS_FLAGS_IS_DONE (1 << 0)
-#define TRANS_FLAGS_HAS_ERROR (1 << 1)
-    volatile unsigned long flags;
-};
-
-#ifndef LIBUSB_CALL
-# define LIBUSB_CALL
-#endif
-
-static void LIBUSB_CALL on_trans_done(struct libusb_transfer * trans) {
-    struct trans_ctx * const ctx = trans->user_data;
-
-    if (trans->status != LIBUSB_TRANSFER_COMPLETED)
-        ctx->flags |= TRANS_FLAGS_HAS_ERROR;
-
-    ctx->flags |= TRANS_FLAGS_IS_DONE;
-}
-
-int submit_wait(struct stlink_libusb *slu, struct libusb_transfer * trans) {
-    struct timeval start;
-    struct timeval now;
-    struct timeval diff;
-    struct trans_ctx trans_ctx;
-    enum libusb_error error;
-
-    trans_ctx.flags = 0;
-
-    /* brief intrusion inside the libusb interface */
-    trans->callback = on_trans_done;
-    trans->user_data = &trans_ctx;
-
-    if ((error = libusb_submit_transfer(trans))) {
-        printf("libusb_submit_transfer(%d)\n", error);
-        return -1;
-    }
-
-    gettimeofday(&start, NULL);
-
-    while (trans_ctx.flags == 0) {
-        struct timeval timeout;
-        timeout.tv_sec = 3;
-        timeout.tv_usec = 0;
-        if (libusb_handle_events_timeout(slu->libusb_ctx, &timeout)) {
-            printf("libusb_handle_events()\n");
-            return -1;
-        }
-
-        gettimeofday(&now, NULL);
-        timersub(&now, &start, &diff);
-        if (diff.tv_sec >= 3) {
-            printf("libusb_handle_events() timeout\n");
-            return -1;
-        }
-    }
-
-    if (trans_ctx.flags & TRANS_FLAGS_HAS_ERROR) {
-        printf("libusb_handle_events() | has_error\n");
-        return -1;
-    }
-
-    return 0;
-}
-
 ssize_t send_recv(struct stlink_libusb* handle, int terminate,
         unsigned char* txbuf, size_t txsize,
         unsigned char* rxbuf, size_t rxsize) {
     /* note: txbuf and rxbuf can point to the same area */
     int res = 0;
 
-    libusb_fill_bulk_transfer(handle->req_trans, handle->usb_handle,
-            handle->ep_req,
-            txbuf, txsize,
-            NULL, NULL,
-            0
-            );
-
-    if (submit_wait(handle, handle->req_trans)) return -1;
+    if (libusb_bulk_transfer(handle->usb_handle, handle->ep_req,
+            txbuf,
+            txsize,
+            &res,
+            3000))
+        return -1;
 
-    /* send_only */
     if (rxsize != 0) {
-
-        /* read the response */
-
-        libusb_fill_bulk_transfer(handle->rep_trans, handle->usb_handle,
-                handle->ep_rep, rxbuf, rxsize, NULL, NULL, 0);
-
-        if (submit_wait(handle, handle->rep_trans)) return -1;
-        res = handle->rep_trans->actual_length;
+        if (libusb_bulk_transfer(handle->usb_handle, handle->ep_rep,
+                rxbuf,
+                rxsize,
+                &res,
+                3000))
+            return -1;
     }
 
     if ((handle->protocoll == 1) && terminate) {
         /* Read the SG reply */
         unsigned char sg_buf[13];
-        libusb_fill_bulk_transfer
-            (handle->rep_trans, handle->usb_handle,
-             handle->ep_rep, sg_buf, 13, NULL, NULL, 0);
-        res = submit_wait(handle, handle->rep_trans);
+        if (libusb_bulk_transfer(handle->usb_handle, handle->ep_rep,
+                sg_buf,
+                13,
+                &res,
+                3000))
+            return -1;
         /* The STLink doesn't seem to evaluate the sequence number */
         handle->sg_transfer_idx++;
-        if (res ) return -1;
     }
 
-    return handle->rep_trans->actual_length;
+    return res;
 }
 
 static inline int send_only
@@ -180,7 +95,7 @@ static int fill_command
     return i;
 }
 
-void _stlink_usb_version(stlink_t *sl) {
+int _stlink_usb_version(stlink_t *sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
@@ -193,8 +108,10 @@ void _stlink_usb_version(stlink_t *sl) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
 int32_t _stlink_usb_target_voltage(stlink_t *sl) {
@@ -225,7 +142,7 @@ int32_t _stlink_usb_target_voltage(stlink_t *sl) {
     return voltage;
 }
 
-uint32_t _stlink_usb_read_debug32(stlink_t *sl, uint32_t addr) {
+int _stlink_usb_read_debug32(stlink_t *sl, uint32_t addr, uint32_t *data) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const rdata = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
@@ -239,12 +156,13 @@ uint32_t _stlink_usb_read_debug32(stlink_t *sl, uint32_t addr) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, rdata, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return 0;
+        return size;
     }
-    return read_uint32(rdata, 4);
+    *data = read_uint32(rdata, 4);
+    return 0;
 }
 
-void _stlink_usb_write_debug32(stlink_t *sl, uint32_t addr, uint32_t data) {
+int _stlink_usb_write_debug32(stlink_t *sl, uint32_t addr, uint32_t data) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const rdata = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
@@ -259,37 +177,54 @@ void _stlink_usb_write_debug32(stlink_t *sl, uint32_t addr, uint32_t data) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, rdata, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
-void _stlink_usb_write_mem32(stlink_t *sl, uint32_t addr, uint16_t len) {
+int _stlink_usb_write_mem32(stlink_t *sl, uint32_t addr, uint16_t len) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
+    int i, ret;
 
-    int i = fill_command(sl, SG_DXFER_TO_DEV, len);
+    i = fill_command(sl, SG_DXFER_TO_DEV, len);
     cmd[i++] = STLINK_DEBUG_COMMAND;
     cmd[i++] = STLINK_DEBUG_WRITEMEM_32BIT;
     write_uint32(&cmd[i], addr);
     write_uint16(&cmd[i + 4], len);
-    send_only(slu, 0, cmd, slu->cmd_len);
+    ret = send_only(slu, 0, cmd, slu->cmd_len);
+    if (ret == -1)
+        return ret;
 
-    send_only(slu, 1, data, len);
+    ret = send_only(slu, 1, data, len);
+    if (ret == -1)
+        return ret;
+
+    return 0;
 }
 
-void _stlink_usb_write_mem8(stlink_t *sl, uint32_t addr, uint16_t len) {
+int _stlink_usb_write_mem8(stlink_t *sl, uint32_t addr, uint16_t len) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
+    int i, ret;
 
-    int i = fill_command(sl, SG_DXFER_TO_DEV, 0);
+    i = fill_command(sl, SG_DXFER_TO_DEV, 0);
     cmd[i++] = STLINK_DEBUG_COMMAND;
     cmd[i++] = STLINK_DEBUG_WRITEMEM_8BIT;
     write_uint32(&cmd[i], addr);
     write_uint16(&cmd[i + 4], len);
-    send_only(slu, 0, cmd, slu->cmd_len);
-    send_only(slu, 1, data, len);
+    ret = send_only(slu, 0, cmd, slu->cmd_len);
+    if (ret == -1)
+        return ret;
+
+    ret = send_only(slu, 1, data, len);
+    if (ret == -1)
+        return ret;
+
+    return 0;
 }
 
 
@@ -310,7 +245,7 @@ int _stlink_usb_current_mode(stlink_t * sl) {
     return sl->q_buf[0];
 }
 
-void _stlink_usb_core_id(stlink_t * sl) {
+int _stlink_usb_core_id(stlink_t * sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const cmd  = sl->c_buf;
     unsigned char* const data = sl->q_buf;
@@ -324,13 +259,14 @@ void _stlink_usb_core_id(stlink_t * sl) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return -1;
     }
 
     sl->core_id = read_uint32(data, 0);
+    return 0;
 }
 
-void _stlink_usb_status(stlink_t * sl) {
+int _stlink_usb_status(stlink_t * sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
@@ -344,11 +280,14 @@ void _stlink_usb_status(stlink_t * sl) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+    sl->q_len = (size_t) size;
+
+    return 0;
 }
 
-void _stlink_usb_force_debug(stlink_t *sl) {
+int _stlink_usb_force_debug(stlink_t *sl) {
     struct stlink_libusb *slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
@@ -361,11 +300,13 @@ void _stlink_usb_force_debug(stlink_t *sl) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
-void _stlink_usb_enter_swd_mode(stlink_t * sl) {
+int _stlink_usb_enter_swd_mode(stlink_t * sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const cmd  = sl->c_buf;
     ssize_t size;
@@ -379,11 +320,13 @@ void _stlink_usb_enter_swd_mode(stlink_t * sl) {
     size = send_only(slu, 1, cmd, slu->cmd_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
-void _stlink_usb_exit_dfu_mode(stlink_t* sl) {
+int _stlink_usb_exit_dfu_mode(stlink_t* sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const cmd = sl->c_buf;
     ssize_t size;
@@ -395,15 +338,17 @@ void _stlink_usb_exit_dfu_mode(stlink_t* sl) {
     size = send_only(slu, 1, cmd, slu->cmd_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
 /**
  * TODO - not convinced this does anything...
  * @param sl
  */
-void _stlink_usb_reset(stlink_t * sl) {
+int _stlink_usb_reset(stlink_t * sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd = sl->c_buf;
@@ -417,12 +362,14 @@ void _stlink_usb_reset(stlink_t * sl) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
 
-void _stlink_usb_jtag_reset(stlink_t * sl, int value) {
+int _stlink_usb_jtag_reset(stlink_t * sl, int value) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd = sl->c_buf;
@@ -432,17 +379,19 @@ void _stlink_usb_jtag_reset(stlink_t * sl, int value) {
 
     cmd[i++] = STLINK_DEBUG_COMMAND;
     cmd[i++] = STLINK_JTAG_DRIVE_NRST;
-    cmd[i++] = (value)?0:1;
+    cmd[i++] = value;
 
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
 
-void _stlink_usb_step(stlink_t* sl) {
+int _stlink_usb_step(stlink_t* sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd = sl->c_buf;
@@ -456,15 +405,17 @@ void _stlink_usb_step(stlink_t* sl) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
 /**
  * This seems to do a good job of restarting things from the beginning?
  * @param sl
  */
-void _stlink_usb_run(stlink_t* sl) {
+int _stlink_usb_run(stlink_t* sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd = sl->c_buf;
@@ -478,11 +429,13 @@ void _stlink_usb_run(stlink_t* sl) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
-void _stlink_usb_exit_debug_mode(stlink_t *sl) {
+int _stlink_usb_exit_debug_mode(stlink_t *sl) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const cmd = sl->c_buf;
     ssize_t size;
@@ -494,11 +447,13 @@ void _stlink_usb_exit_debug_mode(stlink_t *sl) {
     size = send_only(slu, 1, cmd, slu->cmd_len);
     if (size == -1) {
         printf("[!] send_only\n");
-        return;
+        return size;
     }
+
+    return 0;
 }
 
-void _stlink_usb_read_mem32(stlink_t *sl, uint32_t addr, uint16_t len) {
+int _stlink_usb_read_mem32(stlink_t *sl, uint32_t addr, uint16_t len) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd = sl->c_buf;
@@ -513,15 +468,16 @@ void _stlink_usb_read_mem32(stlink_t *sl, uint32_t addr, uint16_t len) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
 
     sl->q_len = (size_t) size;
 
     stlink_print_data(sl);
+    return 0;
 }
 
-void _stlink_usb_read_all_regs(stlink_t *sl, reg *regp) {
+int _stlink_usb_read_all_regs(stlink_t *sl, reg *regp) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const cmd = sl->c_buf;
     unsigned char* const data = sl->q_buf;
@@ -534,7 +490,7 @@ void _stlink_usb_read_all_regs(stlink_t *sl, reg *regp) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
     sl->q_len = (size_t) size;
     stlink_print_data(sl);
@@ -546,16 +502,18 @@ void _stlink_usb_read_all_regs(stlink_t *sl, reg *regp) {
     regp->rw         = read_uint32(sl->q_buf, 76);
     regp->rw2        = read_uint32(sl->q_buf, 80);
     if (sl->verbose < 2)
-        return;
+        return 0;
 
     DLOG("xpsr       = 0x%08x\n", read_uint32(sl->q_buf, 64));
     DLOG("main_sp    = 0x%08x\n", read_uint32(sl->q_buf, 68));
     DLOG("process_sp = 0x%08x\n", read_uint32(sl->q_buf, 72));
     DLOG("rw         = 0x%08x\n", read_uint32(sl->q_buf, 76));
     DLOG("rw2        = 0x%08x\n", read_uint32(sl->q_buf, 80));
+
+    return 0;
 }
 
-void _stlink_usb_read_reg(stlink_t *sl, int r_idx, reg *regp) {
+int _stlink_usb_read_reg(stlink_t *sl, int r_idx, reg *regp) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
@@ -570,7 +528,7 @@ void _stlink_usb_read_reg(stlink_t *sl, int r_idx, reg *regp) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
     sl->q_len = (size_t) size;
     stlink_print_data(sl);
@@ -596,19 +554,27 @@ void _stlink_usb_read_reg(stlink_t *sl, int r_idx, reg *regp) {
     default:
         regp->r[r_idx] = r;
     }
+
+    return 0;
 }
 
 /* See section C1.6 of the ARMv7-M Architecture Reference Manual */
-void _stlink_usb_read_unsupported_reg(stlink_t *sl, int r_idx, reg *regp) {
+int _stlink_usb_read_unsupported_reg(stlink_t *sl, int r_idx, reg *regp) {
     uint32_t r;
+    int ret;
 
     sl->q_buf[0] = (unsigned char) r_idx;
     for (int i = 1; i < 4; i++) {
         sl->q_buf[i] = 0;
     }
 
-    _stlink_usb_write_mem32(sl, DCRSR, 4);
+    ret = _stlink_usb_write_mem32(sl, DCRSR, 4);
+    if (ret == -1)
+        return ret;
+
     _stlink_usb_read_mem32(sl, DCRDR, 4);
+    if (ret == -1)
+        return ret;
 
     r = read_uint32(sl->q_buf, 0);
     DLOG("r_idx (%2d) = 0x%08x\n", r_idx, r);
@@ -627,22 +593,39 @@ void _stlink_usb_read_unsupported_reg(stlink_t *sl, int r_idx, reg *regp) {
         regp->s[r_idx - 0x40] = r;
         break;
     }
+
+    return 0;
 }
 
-void _stlink_usb_read_all_unsupported_regs(stlink_t *sl, reg *regp) {
-    _stlink_usb_read_unsupported_reg(sl, 0x14, regp);
-    _stlink_usb_read_unsupported_reg(sl, 0x21, regp);
+int _stlink_usb_read_all_unsupported_regs(stlink_t *sl, reg *regp) {
+    int ret;
+
+    ret = _stlink_usb_read_unsupported_reg(sl, 0x14, regp);
+    if (ret == -1)
+        return ret;
+
+    ret = _stlink_usb_read_unsupported_reg(sl, 0x21, regp);
+    if (ret == -1)
+        return ret;
 
     for (int i = 0; i < 32; i++) {
-        _stlink_usb_read_unsupported_reg(sl, 0x40+i, regp);
+        ret = _stlink_usb_read_unsupported_reg(sl, 0x40+i, regp);
+        if (ret == -1)
+            return ret;
     }
+
+    return 0;
 }
 
 /* See section C1.6 of the ARMv7-M Architecture Reference Manual */
-void _stlink_usb_write_unsupported_reg(stlink_t *sl, uint32_t val, int r_idx, reg *regp) {
+int _stlink_usb_write_unsupported_reg(stlink_t *sl, uint32_t val, int r_idx, reg *regp) {
+    int ret;
+
     if (r_idx >= 0x1C && r_idx <= 0x1F) { /* primask, basepri, faultmask, or control */
         /* These are held in the same register */
-        _stlink_usb_read_unsupported_reg(sl, 0x14, regp);
+        ret = _stlink_usb_read_unsupported_reg(sl, 0x14, regp);
+        if (ret == -1)
+            return ret;
 
         val = (uint8_t) (val>>24);
 
@@ -666,17 +649,19 @@ void _stlink_usb_write_unsupported_reg(stlink_t *sl, uint32_t val, int r_idx, re
 
     write_uint32(sl->q_buf, val);
 
-    _stlink_usb_write_mem32(sl, DCRDR, 4);
+    ret = _stlink_usb_write_mem32(sl, DCRDR, 4);
+    if (ret == -1)
+        return ret;
 
     sl->q_buf[0] = (unsigned char) r_idx;
     sl->q_buf[1] = 0;
     sl->q_buf[2] = 0x01;
     sl->q_buf[3] = 0;
 
-    _stlink_usb_write_mem32(sl, DCRSR, 4);
+    return _stlink_usb_write_mem32(sl, DCRSR, 4);
 }
 
-void _stlink_usb_write_reg(stlink_t *sl, uint32_t reg, int idx) {
+int _stlink_usb_write_reg(stlink_t *sl, uint32_t reg, int idx) {
     struct stlink_libusb * const slu = sl->backend_data;
     unsigned char* const data = sl->q_buf;
     unsigned char* const cmd  = sl->c_buf;
@@ -691,10 +676,12 @@ void _stlink_usb_write_reg(stlink_t *sl, uint32_t reg, int idx) {
     size = send_recv(slu, 1, cmd, slu->cmd_len, data, rep_len);
     if (size == -1) {
         printf("[!] send_recv\n");
-        return;
+        return size;
     }
     sl->q_len = (size_t) size;
     stlink_print_data(sl);
+
+    return 0;
 }
 
 stlink_backend_t _stlink_usb_backend = {
@@ -726,27 +713,25 @@ stlink_backend_t _stlink_usb_backend = {
     _stlink_usb_target_voltage
 };
 
-
-stlink_t* stlink_open_usb(const int verbose, int reset) {
+stlink_t *stlink_open_usb(enum ugly_loglevel verbose, bool reset, char serial[16])
+{
     stlink_t* sl = NULL;
     struct stlink_libusb* slu = NULL;
-    int error = -1;
-    libusb_device** devs = NULL;
+    int ret = -1;
     int config;
 
-    sl = malloc(sizeof (stlink_t));
-    slu = malloc(sizeof (struct stlink_libusb));
-    if (sl == NULL) goto on_error;
-    if (slu == NULL) goto on_error;
-    memset(sl, 0, sizeof (stlink_t));
-    memset(slu, 0, sizeof (struct stlink_libusb));
+    sl = calloc(1, sizeof (stlink_t));
+    slu = calloc(1, sizeof (struct stlink_libusb));
+    if (sl == NULL)
+        goto on_malloc_error;
+    if (slu == NULL)
+        goto on_malloc_error;
 
     ugly_init(verbose);
     sl->backend = &_stlink_usb_backend;
     sl->backend_data = slu;
 
     sl->core_stat = STLINK_CORE_STAT_UNKNOWN;
-
     if (libusb_init(&(slu->libusb_ctx))) {
         WLOG("failed to init libusb context, wrong version of libraries?\n");
         goto on_error;
@@ -758,6 +743,10 @@ stlink_t* stlink_open_usb(const int verbose, int reset) {
     int devBus =0;
     int devAddr=0;
 
+    /* @TODO: Reading a environment variable in a usb open function is not very nice, this
+      should be refactored and moved into the CLI tools, and instead of giving USB_BUS:USB_ADDR a real stlink
+      serial string should be passed to this function. Probably people are using this but this is very odd because
+      as programmer can change to multiple busses and it is better to detect them based on serial.  */
     char *device = getenv("STLINK_DEVICE");
     if (device) {
         char *c = strchr(device,':');
@@ -770,13 +759,39 @@ stlink_t* stlink_open_usb(const int verbose, int reset) {
         devAddr=atoi(c);
         ILOG("bus %03d dev %03d\n",devBus, devAddr);
     }
-    while (cnt){
-        cnt--;
+
+    while (cnt--) {
         libusb_get_device_descriptor( list[cnt], &desc );
-        if (desc.idVendor!=USB_ST_VID) continue;
-        if (devBus && devAddr)
-            if ((libusb_get_bus_number(list[cnt])!=devBus) || (libusb_get_device_address(list[cnt])!=devAddr)) continue;
-        if ( (desc.idProduct == USB_STLINK_32L_PID) || (desc.idProduct == USB_STLINK_NUCLEO_PID) ) break;
+        if (desc.idVendor != USB_ST_VID)
+            continue;
+
+        if (devBus && devAddr) {
+            if ((libusb_get_bus_number(list[cnt]) != devBus)
+                || (libusb_get_device_address(list[cnt]) != devAddr)) {
+                continue;
+            }
+        }
+
+        if ((desc.idProduct == USB_STLINK_32L_PID) || (desc.idProduct == USB_STLINK_NUCLEO_PID)) {
+            struct libusb_device_handle *handle;
+
+            libusb_open(list[cnt], &handle);
+            sl->serial_size = libusb_get_string_descriptor_ascii(handle, desc.iSerialNumber,
+                                                                 (unsigned char *)sl->serial, sizeof(sl->serial));
+            libusb_close(handle);
+
+            if ((serial == NULL) || (*serial == 0))
+                 break;
+
+            if (sl->serial_size < 0)
+	         continue;
+
+            if (memcmp(serial, &sl->serial, sl->serial_size) == 0)
+                 break;
+
+            continue;
+        }
+
         if (desc.idProduct == USB_STLINK_PID) {
             slu->protocoll = 1;
             break;
@@ -787,22 +802,20 @@ stlink_t* stlink_open_usb(const int verbose, int reset) {
         WLOG ("Couldn't find %s ST-Link/V2 devices\n",(devBus && devAddr)?"matched":"any");
         goto on_error;
     } else {
-        int error = libusb_open(list[cnt], &slu->usb_handle);
-        if( error !=0 ) {
-            WLOG("Error %d opening ST-Link/V2 device %03d:%03d\n", error, libusb_get_bus_number(list[cnt]), libusb_get_device_address(list[cnt]));
+        ret = libusb_open(list[cnt], &slu->usb_handle);
+        if (ret != 0) {
+            WLOG("Error %d (%s) opening ST-Link/V2 device %03d:%03d\n",
+                 ret, strerror (errno), libusb_get_bus_number(list[cnt]), libusb_get_device_address(list[cnt]));
             goto on_error;
         }
     }
 
     libusb_free_device_list(list, 1);
 
-
     if (libusb_kernel_driver_active(slu->usb_handle, 0) == 1) {
-        int r;
-
-        r = libusb_detach_kernel_driver(slu->usb_handle, 0);
-        if (r<0) {
-            WLOG("libusb_detach_kernel_driver(() error %s\n", strerror(-r));
+        ret = libusb_detach_kernel_driver(slu->usb_handle, 0);
+        if (ret < 0) {
+            WLOG("libusb_detach_kernel_driver(() error %s\n", strerror(-ret));
             goto on_libusb_error;
         }
     }
@@ -823,19 +836,7 @@ stlink_t* stlink_open_usb(const int verbose, int reset) {
     }
 
     if (libusb_claim_interface(slu->usb_handle, 0)) {
-        WLOG("libusb_claim_interface() failed\n");
-        goto on_libusb_error;
-    }
-
-    slu->req_trans = libusb_alloc_transfer(0);
-    if (slu->req_trans == NULL) {
-        WLOG("libusb_alloc_transfer failed\n");
-        goto on_libusb_error;
-    }
-
-    slu->rep_trans = libusb_alloc_transfer(0);
-    if (slu->rep_trans == NULL) {
-        WLOG("libusb_alloc_transfer failed\n");
+        WLOG("Stlink usb device found, but unable to claim (probably already in use?)\n");
         goto on_libusb_error;
     }
 
@@ -851,8 +852,6 @@ stlink_t* stlink_open_usb(const int verbose, int reset) {
     // TODO - never used at the moment, always CMD_SIZE
     slu->cmd_len = (slu->protocoll == 1)? STLINK_SG_SIZE: STLINK_CMD_SIZE;
 
-    /* success */
-
     if (stlink_current_mode(sl) == STLINK_DEV_DFU_MODE) {
         ILOG("-- exit_dfu_mode\n");
         stlink_exit_dfu_mode(sl);
@@ -864,30 +863,145 @@ stlink_t* stlink_open_usb(const int verbose, int reset) {
 
     if (reset) {
         stlink_reset(sl);
+        usleep(10000);
     }
-    stlink_load_device_params(sl);
-    stlink_version(sl);
 
-    error = 0;
+    stlink_version(sl);
+    ret = stlink_load_device_params(sl);
 
 on_libusb_error:
-    if (devs != NULL) {
-        libusb_free_device_list(devs, 1);
-    }
-
-    if (error == -1) {
+    if (ret == -1) {
         stlink_close(sl);
         return NULL;
     }
 
-    /* success */
     return sl;
 
 on_error:
-    if( slu->libusb_ctx)
+    if (slu->libusb_ctx)
         libusb_exit(slu->libusb_ctx);
-    if (sl != NULL) free(sl);
-    if (slu != NULL) free(slu);
-    return 0;
+
+on_malloc_error:
+    if (sl != NULL)
+        free(sl);
+    if (slu != NULL)
+        free(slu);
+
+    return NULL;
 }
 
+static size_t stlink_probe_usb_devs(libusb_device **devs, stlink_t **sldevs[]) {
+    stlink_t **_sldevs;
+    libusb_device *dev;
+    int i = 0;
+    int ret = 0;
+    size_t slcnt = 0;
+    size_t slcur = 0;
+
+    /* Count stlink */
+    while ((dev = devs[i++]) != NULL) {
+        struct libusb_device_descriptor desc;
+        int r = libusb_get_device_descriptor(dev, &desc);
+        if (r < 0) {
+            WLOG("failed to get libusb device descriptor\n");
+            break;
+        }
+
+        if (desc.idProduct != USB_STLINK_32L_PID &&
+            desc.idProduct != USB_STLINK_NUCLEO_PID)
+            continue;
+
+        slcnt++;
+    }
+
+    /* Allocate list of pointers */
+    _sldevs = calloc(slcnt, sizeof(stlink_t *));
+    if (!_sldevs) {
+        *sldevs = NULL;
+        return 0;
+    }
+
+    /* Open stlinks and attach to list */
+    i = 0;
+    while ((dev = devs[i++]) != NULL) {
+        struct libusb_device_descriptor desc;
+        ret = libusb_get_device_descriptor(dev, &desc);
+        if (ret < 0) {
+            WLOG("failed to get libusb device descriptor\n");
+            break;
+        }
+
+        if (desc.idProduct != USB_STLINK_32L_PID &&
+            desc.idProduct != USB_STLINK_NUCLEO_PID)
+            continue;
+
+        struct libusb_device_handle* handle;
+        char serial[13];
+        memset(serial, 0, sizeof(serial));
+
+        ret = libusb_open(dev, &handle);
+        if (ret < 0) {
+            WLOG("failed to get libusb device descriptor\n");
+            break;
+        }
+
+        ret = libusb_get_string_descriptor_ascii(handle, desc.iSerialNumber, (unsigned char *)&serial, sizeof(serial));
+        if (ret < 0)
+          *serial = NULL;
+
+        libusb_close(handle);
+
+        stlink_t *sl = NULL;
+        sl = stlink_open_usb(0, 1, serial);
+        if (!sl)
+            continue;
+
+        _sldevs[slcur] = sl;
+        slcur++;
+    }
+
+    /* Something went wrong */
+    if (ret < 0) {
+        free(_sldevs);
+        *sldevs = NULL;
+        return 0;
+    }
+
+    *sldevs = _sldevs;
+    return slcnt;
+}
+
+size_t stlink_probe_usb(stlink_t **stdevs[]) {
+    libusb_device **devs;
+    stlink_t **sldevs;
+
+    size_t slcnt = 0;
+    int r;
+    ssize_t cnt;
+
+    r = libusb_init(NULL);
+    if (r < 0)
+        return 0;
+
+    cnt = libusb_get_device_list(NULL, &devs);
+    if (cnt < 0)
+        return 0;
+
+    slcnt = stlink_probe_usb_devs(devs, &sldevs);
+    libusb_free_device_list(devs, 1);
+
+    libusb_exit(NULL);
+
+    *stdevs = sldevs;
+    return slcnt;
+}
+
+void stlink_probe_usb_free(stlink_t ***stdevs, size_t size) {
+    if (stdevs == NULL || *stdevs == NULL || size == 0)
+        return;
+
+    for (size_t n = 0; n < size; n++)
+        stlink_close((*stdevs)[n]);
+    free(*stdevs);
+    *stdevs = NULL;
+}