rtt: support channels other than 0

Add support for targets that use channels other than 0. Currently the
channel number is ignored, which duplicates existing functionality,
however furure work may be done to connect other channels to e.g.
different USB endpoints.

Signed-off-by: Sean Cross <[email protected]>

src/include/rtt_if.h

@@ -65,11 +65,11 @@ int rtt_if_init(void);
 /* hosted teardown */
 int rtt_if_exit(void);
 
-/* target to host: write len bytes from the buffer starting at buf. return number bytes written */
-uint32_t rtt_write(const char *buf, uint32_t len);
-/* host to target: read one character, non-blocking. return character, -1 if no character */
-int32_t rtt_getchar(void);
-/* host to target: true if no characters available for reading */
-bool rtt_nodata(void);
+/* target to host: write len bytes from the buffer on the channel starting at buf. return number bytes written */
+uint32_t rtt_write(const uint32_t channel, const char *buf, uint32_t len);
+/* host to target: read one character from the channel, non-blocking. return character, -1 if no character */
+int32_t rtt_getchar(const uint32_t channel);
+/* host to target: true if no characters available for reading in the selected channel */
+bool rtt_nodata(const uint32_t channel);
 
 #endif /* INCLUDE_RTT_IF_H */

src/platforms/common/stm32/rtt_if.c

@@ -93,9 +93,10 @@ void rtt_serial_receive_callback(usbd_device *dev, uint8_t ep)
 }
 
 /* rtt host to target: read one character */
-int32_t rtt_getchar()
+int32_t rtt_getchar(const uint32_t channel)
 {
  int retval;
+ (void)channel;
 
  if (recv_head == recv_tail)
  return -1;
@@ -110,14 +111,20 @@ int32_t rtt_getchar()
 }
 
 /* rtt host to target: true if no characters available for reading */
-bool rtt_nodata()
+bool rtt_nodata(const uint32_t channel)
 {
+ /* only support reading from down channel 0 */
+ if (channel != 0U)
+ return true;
  return recv_head == recv_tail;
 }
 
 /* rtt target to host: write string */
-uint32_t rtt_write(const char *buf, uint32_t len)
+uint32_t rtt_write(const uint32_t channel, const char *buf, uint32_t len)
 {
+ /* only support writing to up channel 0 */
+ if (channel != 0U)
+ return len;
  if (len != 0 && usbdev && usb_get_config() && gdb_serial_get_dtr()) {
  for (uint32_t p = 0; p < len; p += CDCACM_PACKET_SIZE) {
  uint32_t plen = MIN(CDCACM_PACKET_SIZE, len - p);

src/platforms/hosted/rtt_if.c

@@ -71,19 +71,23 @@ int rtt_if_exit()
 
 /* write buffer to terminal */
 
-uint32_t rtt_write(const char *buf, uint32_t len)
+uint32_t rtt_write(const uint32_t channel, const char *buf, uint32_t len)
 {
+ /* only support writing to up channel 0 */
+ if (channel != 0U)
+ return len;
  int unused = write(1, buf, len);
  (void)unused;
  return len;
 }
 
 /* read character from terminal */
 
-int32_t rtt_getchar()
+int32_t rtt_getchar(const uint32_t channel)
 {
  char ch;
  int len;
+ (void)channel;
  len = read(0, &ch, 1);
  if (len == 1)
  return ch;
@@ -92,8 +96,9 @@ int32_t rtt_getchar()
 
 /* true if no characters available */
 
-bool rtt_nodata()
+bool rtt_nodata(const uint32_t channel)
 {
+ (void)channel;
  return false;
 }
 
@@ -113,23 +118,28 @@ int rtt_if_exit()
 
 /* write buffer to terminal */
 
-uint32_t rtt_write(const char *buf, uint32_t len)
+uint32_t rtt_write(const uint32_t channel, const char *buf, uint32_t len)
 {
+ /* only support writing to up channel 0 */
+ if (channel != 0U)
+ return len;
  write(1, buf, len);
  return len;
 }
 
 /* read character from terminal */
 
-int32_t rtt_getchar()
+int32_t rtt_getchar(const uint32_t channel)
 {
+ (void)channel;
  return -1;
 }
 
 /* true if no characters available */
 
-bool rtt_nodata()
+bool rtt_nodata(const uint32_t channel)
 {
+ (void)channel;
  return false;
 }
 

src/platforms/launchpad-icdi/rtt_if.c

@@ -93,9 +93,10 @@ void rtt_serial_receive_callback(usbd_device *dev, uint8_t ep)
 }
 
 /* rtt host to target: read one character */
-int32_t rtt_getchar()
+int32_t rtt_getchar(const uint32_t channel)
 {
  int retval;
+ (void)channel;
 
  if (recv_head == recv_tail)
  return -1;
@@ -110,14 +111,20 @@ int32_t rtt_getchar()
 }
 
 /* rtt host to target: true if no characters available for reading */
-bool rtt_nodata()
+bool rtt_nodata(const uint32_t channel)
 {
+ /* only support reading from down channel 0 */
+ if (channel != 0U)
+ return true;
  return recv_head == recv_tail;
 }
 
 /* rtt target to host: write string */
-uint32_t rtt_write(const char *buf, uint32_t len)
+uint32_t rtt_write(const uint32_t channel, const char *buf, uint32_t len)
 {
+ /* only support writing to up channel 0 */
+ if (channel != 0U)
+ return len;
  if (len != 0 && usbdev && usb_get_config() && gdb_serial_get_dtr()) {
  for (uint32_t p = 0; p < len; p += CDCACM_PACKET_SIZE) {
  uint32_t plen = MIN(CDCACM_PACKET_SIZE, len - p);

src/rtt.c

@@ -222,8 +222,13 @@ static void find_rtt(target_s *const cur_target)
 /* poll if host has new data for target */
 static rtt_retval_e read_rtt(target_s *const cur_target, const uint32_t i)
 {
+ /* down buffers are located in the rtt_channel array after the
+ * up buffers. subtract the index from the total number of
+ * up buffers to get the down buffer number. */
+ uint32_t channel = i - rtt_num_up_chan;
+
  /* copy data from recv_buf to target rtt 'down' buffer */
- if (rtt_nodata())
+ if (rtt_nodata(channel))
  return RTT_IDLE;
 
  if (cur_target == NULL || rtt_channel[i].buf_addr == 0 || rtt_channel[i].buf_size == 0)
@@ -237,7 +242,7 @@ static rtt_retval_e read_rtt(target_s *const cur_target, const uint32_t i)
  const uint32_t next_head = (rtt_channel[i].head + 1U) % rtt_channel[i].buf_size;
  if (rtt_channel[i].tail == next_head)
  break;
- const int ch = rtt_getchar();
+ const int ch = rtt_getchar(channel);
  if (ch == -1)
  break;
  if (target_mem32_write(cur_target, rtt_channel[i].buf_addr + rtt_channel[i].head, &ch, 1))
@@ -320,7 +325,7 @@ static rtt_retval_e print_rtt(target_s *const cur_target, const uint32_t i)
  return RTT_ERR;
 
  /* write buffer to usb */
- rtt_write(xmit_buf, bytes_read);
+ rtt_write(i, xmit_buf, bytes_read);
 
  return RTT_OK;
 }