hla: API: specify that read_reg/write_reg use regsel as parameter

The API of hla have been defined from ST-Link basic operations.
By chance, all the current implementation of hla (st-link, ti-icdi
and nulink) share the same way to handle the parameter 'num' of
the API read_reg() and write_reg(), that is simply using it to
initialize the field REGSEL (bits [6:0]) of armv7m Debug Core
Register Selector Register (DCRSR).

Add a comment in the API definition to highlight this, in case it
get used by a further hla implementation, then rename as 'regsel'
the 'num' parameter.

Change-Id: I4b6a2c7d78b4fc4de2b9b2bdba065414b15c6ba3
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5882
Reviewed-by: Edward Fewell <edwardfewell@hotmail.com>
Tested-by: jenkins
Reviewed-by: Zale Yu
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

src/jtag/drivers/nulink_usb.c

@@ -411,7 +411,7 @@ static int nulink_usb_step(void *handle)
 	return res;
 }
 
-static int nulink_usb_read_reg(void *handle, int num, uint32_t *val)
+static int nulink_usb_read_reg(void *handle, unsigned int regsel, uint32_t *val)
 {
 	struct nulink_usb_handle_s *h = handle;
 
@@ -434,7 +434,7 @@ static int nulink_usb_read_reg(void *handle, int num, uint32_t *val)
 	h->cmdbuf[h->cmdidx] = 0;
 	h->cmdidx += 1;
 	/* u32Addr */
-	h_u32_to_le(h->cmdbuf + h->cmdidx, num);
+	h_u32_to_le(h->cmdbuf + h->cmdidx, regsel);
 	h->cmdidx += 4;
 	/* u32Data */
 	h_u32_to_le(h->cmdbuf + h->cmdidx, 0);
@@ -450,7 +450,7 @@ static int nulink_usb_read_reg(void *handle, int num, uint32_t *val)
 	return res;
 }
 
-static int nulink_usb_write_reg(void *handle, int num, uint32_t val)
+static int nulink_usb_write_reg(void *handle, unsigned int regsel, uint32_t val)
 {
 	struct nulink_usb_handle_s *h = handle;
 
@@ -473,7 +473,7 @@ static int nulink_usb_write_reg(void *handle, int num, uint32_t val)
 	h->cmdbuf[h->cmdidx] = 0;
 	h->cmdidx += 1;
 	/* u32Addr */
-	h_u32_to_le(h->cmdbuf + h->cmdidx, num);
+	h_u32_to_le(h->cmdbuf + h->cmdidx, regsel);
 	h->cmdidx += 4;
 	/* u32Data */
 	h_u32_to_le(h->cmdbuf + h->cmdidx, val);

src/jtag/drivers/stlink_usb.c

@@ -2016,7 +2016,7 @@ static int stlink_usb_read_regs(void *handle)
 }
 
 /** */
-static int stlink_usb_read_reg(void *handle, int num, uint32_t *val)
+static int stlink_usb_read_reg(void *handle, unsigned int regsel, uint32_t *val)
 {
 	int res;
 	struct stlink_usb_handle_s *h = handle;
@@ -2030,7 +2030,7 @@ static int stlink_usb_read_reg(void *handle, int num, uint32_t *val)
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV1_READREG;
 	else
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_READREG;
-	h->cmdbuf[h->cmdidx++] = num;
+	h->cmdbuf[h->cmdidx++] = regsel;
 
 	if (h->version.jtag_api == STLINK_JTAG_API_V1) {
 		res = stlink_usb_xfer_noerrcheck(handle, h->databuf, 4);
@@ -2048,7 +2048,7 @@ 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)
+static int stlink_usb_write_reg(void *handle, unsigned int regsel, uint32_t val)
 {
 	struct stlink_usb_handle_s *h = handle;
 
@@ -2061,7 +2061,7 @@ static int stlink_usb_write_reg(void *handle, int num, uint32_t val)
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV1_WRITEREG;
 	else
 		h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_WRITEREG;
-	h->cmdbuf[h->cmdidx++] = num;
+	h->cmdbuf[h->cmdidx++] = regsel;
 	h_u32_to_le(h->cmdbuf+h->cmdidx, val);
 	h->cmdidx += 4;
 

src/jtag/drivers/ti_icdi_usb.c

@@ -475,13 +475,13 @@ static int icdi_usb_read_regs(void *handle)
 	return ERROR_OK;
 }
 
-static int icdi_usb_read_reg(void *handle, int num, uint32_t *val)
+static int icdi_usb_read_reg(void *handle, unsigned int regsel, uint32_t *val)
 {
 	int result;
 	struct icdi_usb_handle_s *h = handle;
 	char cmd[10];
 
-	snprintf(cmd, sizeof(cmd), "p%x", num);
+	snprintf(cmd, sizeof(cmd), "p%x", regsel);
 	result = icdi_send_cmd(handle, cmd);
 	if (result != ERROR_OK)
 		return result;
@@ -504,14 +504,14 @@ static int icdi_usb_read_reg(void *handle, int num, uint32_t *val)
 	return result;
 }
 
-static int icdi_usb_write_reg(void *handle, int num, uint32_t val)
+static int icdi_usb_write_reg(void *handle, unsigned int regsel, uint32_t val)
 {
 	int result;
 	char cmd[20];
 	uint8_t buf[4];
 	h_u32_to_le(buf, val);
 
-	int cmd_len = snprintf(cmd, sizeof(cmd), "P%x=", num);
+	int cmd_len = snprintf(cmd, sizeof(cmd), "P%x=", regsel);
 	hexify(cmd + cmd_len, buf, 4, sizeof(cmd));
 
 	result = icdi_send_cmd(handle, cmd);

src/jtag/hla/hla_layout.h

@@ -51,10 +51,25 @@ struct hl_layout_api_s {
 	int (*step)(void *handle);
 	/** */
 	int (*read_regs)(void *handle);
-	/** */
-	int (*read_reg)(void *handle, int num, uint32_t *val);
-	/** */
-	int (*write_reg)(void *handle, int num, uint32_t val);
+	/**
+	 * Read one register from the target
+	 *
+	 * @param handle A pointer to the device-specific handle
+	 * @param regsel Register selection index compatible with all the
+	 * values allowed by armv7m DCRSR.REGSEL
+	 * @param val A pointer to retrieve the register value
+	 * @returns ERROR_OK on success, or an error code on failure.
+	 */
+	int (*read_reg)(void *handle, unsigned int regsel, uint32_t *val);
+	/**
+	 * Write one register to the target
+	 * @param handle A pointer to the device-specific handle
+	 * @param regsel Register selection index compatible with all the
+	 * values allowed by armv7m DCRSR.REGSEL
+	 * @param val The value to be written in the register
+	 * @returns ERROR_OK on success, or an error code on failure.
+	 */
+	int (*write_reg)(void *handle, unsigned int regsel, uint32_t val);
 	/** */
 	int (*read_mem)(void *handle, uint32_t addr, uint32_t size,
 			uint32_t count, uint8_t *buffer);