X-Git-Url: https://review.openocd.org/gitweb?a=blobdiff_plain;f=src%2Fjtag%2Fdrivers%2Fstlink_usb.c;h=5574a40bae49ec9e1a377908bbf2963c26158e67;hb=fb5e099af83a17821e6962b6e632582cb5033a66;hp=31f08cbb8eb2687573ad620d4817c73fbea05af4;hpb=cfe9ca039f4f6c058dff64effea50a857ff80f96;p=openocd.git

diff --git a/src/jtag/drivers/stlink_usb.c b/src/jtag/drivers/stlink_usb.c
index 31f08cbb8e..5574a40bae 100644
--- a/src/jtag/drivers/stlink_usb.c
+++ b/src/jtag/drivers/stlink_usb.c
@@ -45,14 +45,22 @@
 #define STLINK_WRITE_TIMEOUT 1000
 #define STLINK_READ_TIMEOUT 1000
 
-#define STLINK_NULL_EP     0
-#define STLINK_RX_EP       (1|ENDPOINT_IN)
-#define STLINK_TX_EP       (2|ENDPOINT_OUT)
-#define STLINK_TRACE_EP    (3|ENDPOINT_IN)
-#define STLINK_SG_SIZE     (31)
-#define STLINK_DATA_SIZE   (4096)
-#define STLINK_CMD_SIZE_V2 (16)
-#define STLINK_CMD_SIZE_V1 (10)
+#define STLINK_NULL_EP        0
+#define STLINK_RX_EP          (1|ENDPOINT_IN)
+#define STLINK_TX_EP          (2|ENDPOINT_OUT)
+#define STLINK_TRACE_EP       (3|ENDPOINT_IN)
+
+#define STLINK_V2_1_TX_EP     (1|ENDPOINT_OUT)
+#define STLINK_V2_1_TRACE_EP  (2|ENDPOINT_IN)
+
+#define STLINK_SG_SIZE        (31)
+#define STLINK_DATA_SIZE      (4096)
+#define STLINK_CMD_SIZE_V2    (16)
+#define STLINK_CMD_SIZE_V1    (10)
+
+#define STLINK_V1_PID         (0x3744)
+#define STLINK_V2_PID         (0x3748)
+#define STLINK_V2_1_PID       (0x374B)
 
 /* the current implementation of the stlink limits
  * 8bit read/writes to max 64 bytes. */
@@ -82,6 +90,12 @@ struct stlink_usb_handle_s {
 	/** */
 	struct libusb_transfer *trans;
 	/** */
+	uint8_t rx_ep;
+	/** */
+	uint8_t tx_ep;
+	/** */
+	uint8_t trace_ep;
+	/** */
 	uint8_t cmdbuf[STLINK_SG_SIZE];
 	/** */
 	uint8_t cmdidx;
@@ -112,6 +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
@@ -209,16 +226,14 @@ static void stlink_usb_init_buffer(void *handle, uint8_t direction, uint32_t siz
 /** */
 static int stlink_usb_xfer_v1_get_status(void *handle)
 {
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	/* read status */
 	memset(h->cmdbuf, 0, STLINK_SG_SIZE);
 
-	if (jtag_libusb_bulk_read(h->fd, STLINK_RX_EP, (char *)h->cmdbuf,
+	if (jtag_libusb_bulk_read(h->fd, h->rx_ep, (char *)h->cmdbuf,
 			13, STLINK_READ_TIMEOUT) != 13)
 		return ERROR_FAIL;
 
@@ -244,25 +259,23 @@ static int stlink_usb_xfer_v1_get_status(void *handle)
 /** */
 static int stlink_usb_xfer_rw(void *handle, int cmdsize, const uint8_t *buf, int size)
 {
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	if (jtag_libusb_bulk_write(h->fd, STLINK_TX_EP, (char *)h->cmdbuf, cmdsize,
+	if (jtag_libusb_bulk_write(h->fd, h->tx_ep, (char *)h->cmdbuf, cmdsize,
 			STLINK_WRITE_TIMEOUT) != cmdsize) {
 		return ERROR_FAIL;
 	}
 
-	if (h->direction == STLINK_TX_EP && size) {
-		if (jtag_libusb_bulk_write(h->fd, STLINK_TX_EP, (char *)buf,
+	if (h->direction == h->tx_ep && size) {
+		if (jtag_libusb_bulk_write(h->fd, h->tx_ep, (char *)buf,
 				size, STLINK_WRITE_TIMEOUT) != size) {
 			LOG_DEBUG("bulk write failed");
 			return ERROR_FAIL;
 		}
-	} else if (h->direction == STLINK_RX_EP && size) {
-		if (jtag_libusb_bulk_read(h->fd, STLINK_RX_EP, (char *)buf,
+	} else if (h->direction == h->rx_ep && size) {
+		if (jtag_libusb_bulk_read(h->fd, h->rx_ep, (char *)buf,
 				size, STLINK_READ_TIMEOUT) != size) {
 			LOG_DEBUG("bulk read failed");
 			return ERROR_FAIL;
@@ -276,13 +289,11 @@ static int stlink_usb_xfer_rw(void *handle, int cmdsize, const uint8_t *buf, int
 static int stlink_usb_xfer_v1_get_sense(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 16);
+	stlink_usb_init_buffer(handle, h->rx_ep, 16);
 
 	h->cmdbuf[h->cmdidx++] = REQUEST_SENSE;
 	h->cmdbuf[h->cmdidx++] = 0;
@@ -305,12 +316,10 @@ static int stlink_usb_xfer_v1_get_sense(void *handle)
 static int stlink_usb_xfer(void *handle, const uint8_t *buf, int size)
 {
 	int err, cmdsize = STLINK_CMD_SIZE_V2;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->version.stlink == 1)
 		cmdsize = STLINK_SG_SIZE;
 
@@ -337,15 +346,13 @@ static int stlink_usb_xfer(void *handle, const uint8_t *buf, int size)
 /** */
 static int stlink_usb_read_trace(void *handle, const uint8_t *buf, int size)
 {
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	assert(h->version.stlink >= 2);
 
-	if (jtag_libusb_bulk_read(h->fd, STLINK_TRACE_EP, (char *)buf,
+	if (jtag_libusb_bulk_read(h->fd, h->trace_ep, (char *)buf,
 			size, STLINK_READ_TIMEOUT) != size) {
 		LOG_ERROR("bulk trace read failed");
 		return ERROR_FAIL;
@@ -357,9 +364,7 @@ static int stlink_usb_read_trace(void *handle, const uint8_t *buf, int size)
 /** */
 static void stlink_usb_xfer_v1_create_cmd(void *handle, uint8_t direction, uint32_t size)
 {
-	struct stlink_usb_handle_s *h;
-
-	h = (struct stlink_usb_handle_s *)handle;
+	struct stlink_usb_handle_s *h = handle;
 
 	/* fill the send buffer */
 	strcpy((char *)h->cmdbuf, "USBC");
@@ -368,7 +373,7 @@ static void stlink_usb_xfer_v1_create_cmd(void *handle, uint8_t direction, uint3
 	h->cmdidx += 4;
 	buf_set_u32(h->cmdbuf+h->cmdidx, 0, 32, size);
 	h->cmdidx += 4;
-	h->cmdbuf[h->cmdidx++] = (direction == STLINK_RX_EP ? ENDPOINT_IN : ENDPOINT_OUT);
+	h->cmdbuf[h->cmdidx++] = (direction == h->rx_ep ? ENDPOINT_IN : ENDPOINT_OUT);
 	h->cmdbuf[h->cmdidx++] = 0; /* lun */
 	h->cmdbuf[h->cmdidx++] = STLINK_CMD_SIZE_V1;
 }
@@ -376,9 +381,7 @@ static void stlink_usb_xfer_v1_create_cmd(void *handle, uint8_t direction, uint3
 /** */
 static void stlink_usb_init_buffer(void *handle, uint8_t direction, uint32_t size)
 {
-	struct stlink_usb_handle_s *h;
-
-	h = (struct stlink_usb_handle_s *)handle;
+	struct stlink_usb_handle_s *h = handle;
 
 	h->direction = direction;
 
@@ -400,12 +403,10 @@ static int stlink_usb_error_check(void *handle)
 {
 	int res;
 	const char *err_msg = 0;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	/* TODO: no error checking yet on api V1 */
 	if (h->jtag_api == STLINK_JTAG_API_V1)
 		h->databuf[0] = STLINK_DEBUG_ERR_OK;
@@ -432,13 +433,11 @@ static int stlink_usb_version(void *handle)
 {
 	int res;
 	uint16_t v;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 6);
+	stlink_usb_init_buffer(handle, h->rx_ep, 6);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_GET_VERSION;
 
@@ -476,16 +475,14 @@ static int stlink_usb_version(void *handle)
 
 static int stlink_usb_check_voltage(void *handle, float *target_voltage)
 {
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 	uint32_t adc_results[2];
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	/* only supported by stlink/v2 and for firmware >= 13 */
 	if (h->version.stlink == 1 || h->version.jtag < 13)
 		return ERROR_COMMAND_NOTFOUND;
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 8);
+	stlink_usb_init_buffer(handle, h->rx_ep, 8);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_GET_TARGET_VOLTAGE;
 
@@ -512,13 +509,11 @@ static int stlink_usb_check_voltage(void *handle, float *target_voltage)
 static int stlink_usb_current_mode(void *handle, uint8_t *mode)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_GET_CURRENT_MODE;
 
@@ -537,12 +532,10 @@ static int stlink_usb_mode_enter(void *handle, enum stlink_mode type)
 {
 	int res;
 	int rx_size = 0;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	/* on api V2 we are able the read the latest command
 	 * status
 	 * TODO: we need the test on api V1 too
@@ -550,7 +543,7 @@ static int stlink_usb_mode_enter(void *handle, enum stlink_mode type)
 	if (h->jtag_api == STLINK_JTAG_API_V2)
 		rx_size = 2;
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, rx_size);
+	stlink_usb_init_buffer(handle, h->rx_ep, rx_size);
 
 	switch (type) {
 		case STLINK_MODE_DEBUG_JTAG:
@@ -593,12 +586,10 @@ static int stlink_usb_mode_enter(void *handle, enum stlink_mode type)
 static int stlink_usb_mode_leave(void *handle, enum stlink_mode type)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	stlink_usb_init_buffer(handle, STLINK_NULL_EP, 0);
 
 	switch (type) {
@@ -630,18 +621,30 @@ 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)
 {
 	int res;
 	uint8_t mode;
 	enum stlink_mode emode;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	res = stlink_usb_current_mode(handle, &mode);
 
 	if (res != ERROR_OK)
@@ -705,20 +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");
@@ -750,13 +740,11 @@ static int stlink_usb_init_mode(void *handle, bool connect_under_reset)
 static int stlink_usb_idcode(void *handle, uint32_t *idcode)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 4);
+	stlink_usb_init_buffer(handle, h->rx_ep, 4);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_READCOREID;
@@ -768,21 +756,19 @@ static int stlink_usb_idcode(void *handle, uint32_t *idcode)
 
 	*idcode = le_to_h_u32(h->databuf);
 
-	LOG_DEBUG("IDCODE: 0x%08X", *idcode);
+	LOG_DEBUG("IDCODE: 0x%08" PRIX32, *idcode);
 
 	return ERROR_OK;
 }
 
 static int stlink_usb_v2_read_debug_reg(void *handle, uint32_t addr, uint32_t *val)
 {
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 	int res;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 8);
+	stlink_usb_init_buffer(handle, h->rx_ep, 8);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_READDEBUGREG;
@@ -802,13 +788,11 @@ static int stlink_usb_v2_read_debug_reg(void *handle, uint32_t addr, uint32_t *v
 static int stlink_usb_write_debug_reg(void *handle, uint32_t addr, uint32_t val)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	if (h->jtag_api == STLINK_JTAG_API_V1)
@@ -831,16 +815,14 @@ static int stlink_usb_write_debug_reg(void *handle, uint32_t addr, uint32_t val)
 /** */
 static void stlink_usb_trace_read(void *handle)
 {
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->trace.enabled && h->version.jtag >= STLINK_TRACE_MIN_VERSION) {
 		int res;
 
-		stlink_usb_init_buffer(handle, STLINK_RX_EP, 10);
+		stlink_usb_init_buffer(handle, h->rx_ep, 10);
 
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_GET_TRACE_NB;
@@ -855,15 +837,23 @@ static void stlink_usb_trace_read(void *handle)
 
 				res = stlink_usb_read_trace(handle, buf, size);
 				if (res == ERROR_OK) {
-					/* Log retrieved trace output */
-					if (fwrite(buf, 1, size, h->trace.output_f) > 0)
-						fflush(h->trace.output_f);
+					if (h->trace.output_f) {
+						/* Log retrieved trace output */
+						if (fwrite(buf, 1, size, h->trace.output_f) > 0)
+							fflush(h->trace.output_f);
+					}
 				}
 			}
 		}
 	}
 }
 
+static int stlink_usb_trace_read_callback(void *handle)
+{
+	stlink_usb_trace_read(handle);
+	return ERROR_OK;
+}
+
 static enum target_state stlink_usb_v2_get_status(void *handle)
 {
 	int result;
@@ -887,16 +877,28 @@ static enum target_state stlink_usb_v2_get_status(void *handle)
 static enum target_state stlink_usb_state(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)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 (h->jtag_api == STLINK_JTAG_API_V2)
-		return stlink_usb_v2_get_status(handle);
+		if (res != ERROR_OK)
+			return TARGET_UNKNOWN;
+
+		h->reconnect_pending = false;
+	}
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	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);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_GETSTATUS;
@@ -911,6 +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;
 }
 
@@ -918,13 +922,11 @@ static enum target_state stlink_usb_state(void *handle)
 static int stlink_usb_reset(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 
@@ -950,16 +952,14 @@ static int stlink_usb_reset(void *handle)
 static int stlink_usb_assert_srst(void *handle, int srst)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->jtag_api == STLINK_JTAG_API_V1)
 		return ERROR_COMMAND_NOTFOUND;
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_DRIVE_NRST;
@@ -978,12 +978,10 @@ static int stlink_configure_target_trace_port(void *handle)
 {
 	int res;
 	uint32_t reg;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	/* configure the TPI */
 
 	/* enable the trace subsystem */
@@ -1035,23 +1033,23 @@ out:
 static void stlink_usb_trace_disable(void *handle)
 {
 	int res = ERROR_OK;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	assert(h->version.jtag >= STLINK_TRACE_MIN_VERSION);
 
 	LOG_DEBUG("Tracing: disable\n");
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_STOP_TRACE_RX;
 	res = stlink_usb_xfer(handle, h->databuf, 2);
 
-	if (res == ERROR_OK)
+	if (res == ERROR_OK) {
 		h->trace.enabled = false;
+		target_unregister_timer_callback(stlink_usb_trace_read_callback, handle);
+	}
 }
 
 
@@ -1059,12 +1057,10 @@ static void stlink_usb_trace_disable(void *handle)
 static int stlink_usb_trace_enable(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->version.jtag >= STLINK_TRACE_MIN_VERSION) {
 		uint32_t trace_hz;
 
@@ -1076,7 +1072,7 @@ static int stlink_usb_trace_enable(void *handle)
 			h->trace.source_hz / (h->trace.prescale + 1) :
 			h->trace.source_hz;
 
-		stlink_usb_init_buffer(handle, STLINK_RX_EP, 10);
+		stlink_usb_init_buffer(handle, h->rx_ep, 10);
 
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_START_TRACE_RX;
@@ -1089,7 +1085,15 @@ static int stlink_usb_trace_enable(void *handle)
 
 		if (res == ERROR_OK)  {
 			h->trace.enabled = true;
-			LOG_DEBUG("Tracing: recording at %uHz\n", trace_hz);
+			LOG_DEBUG("Tracing: recording at %" PRIu32 "Hz\n", trace_hz);
+			/* We need the trace read function to be called at a
+			 * high-enough frequency to ensure reasonable
+			 * "timeliness" in processing ITM/DWT data.
+			 * TODO: An alternative could be using the asynchronous
+			 * features of the libusb-1.0 API to queue up one or more
+			 * reads in advance and requeue them once they are
+			 * completed. */
+			target_register_timer_callback(stlink_usb_trace_read_callback, 1, 1, handle);
 		}
 	} else {
 		LOG_ERROR("Tracing is not supported by this version.");
@@ -1103,17 +1107,15 @@ static int stlink_usb_trace_enable(void *handle)
 static int stlink_usb_run(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->jtag_api == STLINK_JTAG_API_V2) {
 		res = stlink_usb_write_debug_reg(handle, DCB_DHCSR, DBGKEY|C_DEBUGEN);
 
 		/* Try to start tracing, if requested */
-		if (res == ERROR_OK && h->trace.output_f) {
+		if (res == ERROR_OK && h->trace.source_hz && !h->trace.enabled) {
 			if (stlink_usb_trace_enable(handle) == ERROR_OK)
 				LOG_DEBUG("Tracing: enabled\n");
 			else
@@ -1123,7 +1125,7 @@ static int stlink_usb_run(void *handle)
 		return res;
 	}
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_RUNCORE;
@@ -1140,12 +1142,10 @@ static int stlink_usb_run(void *handle)
 static int stlink_usb_halt(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->jtag_api == STLINK_JTAG_API_V2) {
 		res = stlink_usb_write_debug_reg(handle, DCB_DHCSR, DBGKEY|C_HALT|C_DEBUGEN);
 
@@ -1155,7 +1155,7 @@ static int stlink_usb_halt(void *handle)
 		return res;
 	}
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_FORCEDEBUG;
@@ -1172,12 +1172,10 @@ static int stlink_usb_halt(void *handle)
 static int stlink_usb_step(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->jtag_api == STLINK_JTAG_API_V2) {
 		/* TODO: this emulates the v1 api, it should really use a similar auto mask isr
 		 * that the cortex-m3 currently does. */
@@ -1186,7 +1184,7 @@ static int stlink_usb_step(void *handle)
 		return stlink_usb_write_debug_reg(handle, DCB_DHCSR, DBGKEY|C_HALT|C_DEBUGEN);
 	}
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_STEPCORE;
@@ -1203,13 +1201,11 @@ static int stlink_usb_step(void *handle)
 static int stlink_usb_read_regs(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 84);
+	stlink_usb_init_buffer(handle, h->rx_ep, 84);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	if (h->jtag_api == STLINK_JTAG_API_V1)
@@ -1229,13 +1225,11 @@ static int stlink_usb_read_regs(void *handle)
 static int stlink_usb_read_reg(void *handle, int num, uint32_t *val)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, h->jtag_api == STLINK_JTAG_API_V1 ? 4 : 8);
+	stlink_usb_init_buffer(handle, h->rx_ep, h->jtag_api == STLINK_JTAG_API_V1 ? 4 : 8);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	if (h->jtag_api == STLINK_JTAG_API_V1)
@@ -1263,13 +1257,11 @@ static int stlink_usb_read_reg(void *handle, int num, uint32_t *val)
 static int stlink_usb_write_reg(void *handle, int num, uint32_t val)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	if (h->jtag_api == STLINK_JTAG_API_V1)
@@ -1291,16 +1283,14 @@ static int stlink_usb_write_reg(void *handle, int num, uint32_t val)
 static int stlink_usb_get_rw_status(void *handle)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
-	h = (struct stlink_usb_handle_s *)handle;
-
 	if (h->jtag_api == STLINK_JTAG_API_V1)
 		return ERROR_OK;
 
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, 2);
+	stlink_usb_init_buffer(handle, h->rx_ep, 2);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_GETLASTRWSTATUS;
@@ -1319,7 +1309,7 @@ static int stlink_usb_read_mem8(void *handle, uint32_t addr, uint16_t len,
 {
 	int res;
 	uint16_t read_len = len;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
@@ -1329,9 +1319,7 @@ static int stlink_usb_read_mem8(void *handle, uint32_t addr, uint16_t len,
 		return ERROR_FAIL;
 	}
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, read_len);
+	stlink_usb_init_buffer(handle, h->rx_ep, read_len);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_READMEM_8BIT;
@@ -1359,7 +1347,7 @@ static int stlink_usb_write_mem8(void *handle, uint32_t addr, uint16_t len,
 			   const uint8_t *buffer)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
@@ -1369,9 +1357,7 @@ static int stlink_usb_write_mem8(void *handle, uint32_t addr, uint16_t len,
 		return ERROR_FAIL;
 	}
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_TX_EP, len);
+	stlink_usb_init_buffer(handle, h->tx_ep, len);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_WRITEMEM_8BIT;
@@ -1393,7 +1379,7 @@ static int stlink_usb_read_mem32(void *handle, uint32_t addr, uint16_t len,
 			  uint8_t *buffer)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
@@ -1403,9 +1389,7 @@ static int stlink_usb_read_mem32(void *handle, uint32_t addr, uint16_t len,
 		return ERROR_TARGET_UNALIGNED_ACCESS;
 	}
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_RX_EP, len);
+	stlink_usb_init_buffer(handle, h->rx_ep, len);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_READMEM_32BIT;
@@ -1429,7 +1413,7 @@ static int stlink_usb_write_mem32(void *handle, uint32_t addr, uint16_t len,
 			   const uint8_t *buffer)
 {
 	int res;
-	struct stlink_usb_handle_s *h;
+	struct stlink_usb_handle_s *h = handle;
 
 	assert(handle != NULL);
 
@@ -1439,9 +1423,7 @@ static int stlink_usb_write_mem32(void *handle, uint32_t addr, uint16_t len,
 		return ERROR_TARGET_UNALIGNED_ACCESS;
 	}
 
-	h = (struct stlink_usb_handle_s *)handle;
-
-	stlink_usb_init_buffer(handle, STLINK_TX_EP, len);
+	stlink_usb_init_buffer(handle, h->tx_ep, len);
 
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND;
 	h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_WRITEMEM_32BIT;
@@ -1471,7 +1453,7 @@ static int stlink_usb_read_mem(void *handle, uint32_t addr, uint32_t size,
 {
 	int retval = ERROR_OK;
 	uint32_t bytes_remaining;
-	struct stlink_usb_handle_s *h = (struct stlink_usb_handle_s *)handle;
+	struct stlink_usb_handle_s *h = handle;
 
 	/* calculate byte count */
 	count *= size;
@@ -1532,7 +1514,7 @@ static int stlink_usb_write_mem(void *handle, uint32_t addr, uint32_t size,
 {
 	int retval = ERROR_OK;
 	uint32_t bytes_remaining;
-	struct stlink_usb_handle_s *h = (struct stlink_usb_handle_s *)handle;
+	struct stlink_usb_handle_s *h = handle;
 
 	/* calculate byte count */
 	count *= size;
@@ -1591,9 +1573,7 @@ static int stlink_usb_write_mem(void *handle, uint32_t addr, uint32_t size,
 /** */
 static int stlink_usb_close(void *fd)
 {
-	struct stlink_usb_handle_s *h;
-
-	h = (struct stlink_usb_handle_s *)fd;
+	struct stlink_usb_handle_s *h = fd;
 
 	if (h->fd)
 		jtag_libusb_close(h->fd);
@@ -1649,14 +1629,28 @@ static int stlink_usb_open(struct hl_interface_param_s *param, void **fd)
 			goto error_open;
 		}
 
+		/* RX EP is common for all versions */
+		h->rx_ep = STLINK_RX_EP;
+
 		/* wrap version for first read */
 		switch (param->pid) {
-		case 0x3744:
-			h->version.stlink = 1;
-			break;
-		default:
-			h->version.stlink = 2;
-			break;
+			case STLINK_V1_PID:
+				h->version.stlink = 1;
+				h->tx_ep = STLINK_TX_EP;
+				h->trace_ep = STLINK_TRACE_EP;
+				break;
+			case STLINK_V2_1_PID:
+				h->version.stlink = 2;
+				h->tx_ep = STLINK_V2_1_TX_EP;
+				h->trace_ep = STLINK_V2_1_TRACE_EP;
+				break;
+			default:
+			/* fall through - we assume V2 to be the default version*/
+			case STLINK_V2_PID:
+				h->version.stlink = 2;
+				h->tx_ep = STLINK_TX_EP;
+				h->trace_ep = STLINK_TRACE_EP;
+				break;
 		}
 
 		/* get the device version */
@@ -1722,17 +1716,12 @@ static int stlink_usb_open(struct hl_interface_param_s *param, void **fd)
 
 	api = h->version.jtag_api_max;
 
-	/* check that user has not requested certain api version
-	 * and if they have check it is supported */
-	if ((param->api != 0) && (param->api <= h->version.jtag_api_max)) {
-		api = param->api;
-		LOG_INFO("using stlink api v%d", api);
-	}
+	LOG_INFO("using stlink api v%d", api);
 
 	/* set the used jtag api, this will default to the newest supported version */
 	h->jtag_api = api;
 
-	if (h->jtag_api >= 2 && param->trace_f && param->trace_source_hz > 0) {
+	if (h->jtag_api >= 2 && param->trace_source_hz > 0) {
 		uint32_t prescale;
 
 		prescale = param->trace_source_hz > STLINK_TRACE_MAX_HZ ?