Implement semihosting debug output redirection to usb-uart port.

src/include/general.h

@@ -74,6 +74,8 @@ enum BMP_DEBUG {
 # define DEBUG_PROBE(...) do {} while(0)
 # define DEBUG_WIRE(...) do {} while(0)
 # define DEBUG_GDB_WIRE(...) do {} while(0)
+
+void usbuart_send_stdout(const uint8_t *data, uint32_t len);
 #else
 # include <stdarg.h>
 extern int cl_debuglevel;
@@ -171,4 +173,3 @@ static inline void DEBUG_WIRE(const char *format, ...)
 #define MORSECNT ((SYSTICKHZ / 10) - 1)
 
 #endif
-

src/platforms/hydrabus/platform.h

@@ -31,6 +31,7 @@
 
 #include <setjmp.h>
 
+#define PLATFORM_HAS_USBUART
 #define PLATFORM_HAS_TRACESWO
 #define PLATFORM_IDENT        " (HydraBus))"
 

src/platforms/launchpad-icdi/platform.h

@@ -22,6 +22,7 @@
 
 #include "timing.h"
 
+#define PLATFORM_HAS_USBUART
 #define PLATFORM_IDENT      "(Launchpad ICDI) "
 
 extern uint8_t running_status;

src/platforms/native/platform.h

@@ -30,6 +30,7 @@
 
 #define PLATFORM_HAS_TRACESWO
 #define PLATFORM_HAS_POWER_SWITCH
+#define PLATFORM_HAS_USBUART
 
 #ifdef ENABLE_DEBUG
 # define PLATFORM_HAS_DEBUG

src/platforms/stlink/platform.h

@@ -39,6 +39,7 @@ extern bool debug_bmp;
 int usbuart_debug_write(const char *buf, size_t len);
 #endif
 
+#define PLATFORM_HAS_USBUART
 #define PLATFORM_IDENT   "(STLINK/V2) "
 
 /* Hardware definitions... */

src/platforms/stm32/usbuart.c

@@ -192,6 +192,20 @@ void usbuart_init(void)
 	usart_enable_rx_dma(USBUSART);
 }
 
+void usbuart_send_stdout(const uint8_t *data, uint32_t len)
+{
+	while (len) {
+		uint32_t cnt = CDCACM_PACKET_SIZE;
+		if (cnt > len)
+			cnt = len;
+		nvic_disable_irq(USB_IRQ);
+		cnt = usbd_ep_write_packet(usbdev, CDCACM_UART_ENDPOINT, data, cnt);
+		nvic_enable_irq(USB_IRQ);
+		data += cnt;
+		len -= cnt;
+	}
+}
+
 void usbuart_set_line_coding(struct usb_cdc_line_coding *coding)
 {
 	usart_set_baudrate(USBUSART, coding->dwDTERate);

src/platforms/swlink/platform.h

@@ -36,6 +36,7 @@ extern bool debug_bmp;
 int usbuart_debug_write(const char *buf, size_t len);
 #endif
 
+#define PLATFORM_HAS_USBUART
 #define PLATFORM_IDENT		"(SWLINK) "
 
 /* Hardware definitions... */

src/platforms/tm4c/usbuart.c

@@ -73,6 +73,20 @@ void usbuart_init(void)
 	nvic_enable_irq(USBUART_IRQ);
 }
 
+void usbuart_send_stdout(const uint8_t *data, uint32_t len)
+{
+	while (len) {
+		uint32_t cnt = CDCACM_PACKET_SIZE;
+		if (cnt > len)
+			cnt = len;
+		nvic_disable_irq(USBUART_IRQ);
+		cnt = usbd_ep_write_packet(usbdev, CDCACM_UART_ENDPOINT, data, cnt);
+		nvic_enable_irq(USBUART_IRQ);
+		data += cnt;
+		len -= cnt;
+	}
+}
+
 void usbuart_set_line_coding(struct usb_cdc_line_coding *coding)
 {
 	uart_set_baudrate(USBUART, coding->dwDTERate);
@@ -180,4 +194,3 @@ void USBUART_ISR(void)
 		buf_rx_out %= FIFO_SIZE;
 	}
 }
-

src/target/cortexm.c

@@ -58,9 +58,15 @@
 static const char cortexm_driver_str[] = "ARM Cortex-M";
 
 static bool cortexm_vector_catch(target *t, int argc, char *argv[]);
+#ifdef PLATFORM_HAS_USBUART
+static bool cortexm_redirect_stdout(target *t, int argc, const char **argv);
+#endif
 
 const struct command_s cortexm_cmd_list[] = {
 	{"vector_catch", (cmd_handler)cortexm_vector_catch, "Catch exception vectors"},
+#ifdef PLATFORM_HAS_USBUART
+	{"redirect_stdout", (cmd_handler)cortexm_redirect_stdout, "Redirect semihosting stdout to USB UART"},
+#endif
 	{NULL, NULL, NULL}
 };
 
@@ -1207,6 +1213,17 @@ static bool cortexm_vector_catch(target *t, int argc, char *argv[])
 #define SYS_WRITEC	0x03
 #define SYS_WRITE0	0x04
 
+#ifdef PLATFORM_HAS_USBUART
+static bool cortexm_redirect_stdout(target *t, int argc, const char **argv)
+{
+	if (argc == 1)
+		gdb_outf("Semihosting stdout redirection: %s\n", t->stdout_redirected ? "enabled" : "disabled");
+	else
+		t->stdout_redirected = !strncmp(argv[1], "enable", strlen(argv[1]));
+	return true;
+}
+#endif
+
 #if PC_HOSTED == 0
 /* probe memory access functions */
 static void probe_mem_read(target *t __attribute__((unused)), void *probe_dest, target_addr target_src, size_t len)
@@ -1216,7 +1233,6 @@ static void probe_mem_read(target *t __attribute__((unused)), void *probe_dest,
 
 	DEBUG_INFO("probe_mem_read\n");
 	while (len--) *dst++=*src++;
-	return;
 }
 
 static void probe_mem_write(target *t __attribute__((unused)), target_addr target_dest, const void *probe_src, size_t len)
@@ -1226,7 +1242,6 @@ static void probe_mem_write(target *t __attribute__((unused)), target_addr targe
 
 	DEBUG_INFO("probe_mem_write\n");
 	while (len--) *dst++=*src++;
-	return;
 }
 #endif
 

src/target/target.c

@@ -22,9 +22,12 @@
 #include "target_internal.h"
 
 #include <stdarg.h>
+#include <unistd.h>
 
 target *target_list = NULL;
 
+#define STDOUT_READ_BUF_SIZE	64
+
 static int target_flash_write_buffered(struct target_flash *f,
                                        target_addr dest, const void *src, size_t len);
 static int target_flash_done_buffered(struct target_flash *f);
@@ -630,6 +633,22 @@ int tc_read(target *t, int fd, target_addr buf, unsigned int count)
 
 int tc_write(target *t, int fd, target_addr buf, unsigned int count)
 {
+#ifdef PLATFORM_HAS_USBUART
+	if (t->stdout_redirected && (fd == STDOUT_FILENO || fd == STDERR_FILENO)) {
+		while (count) {
+			uint8_t tmp[STDOUT_READ_BUF_SIZE];
+			unsigned int cnt = sizeof(tmp);
+			if (cnt > count)
+				cnt = count;
+			target_mem_read(t, tmp, buf, cnt);
+			usbuart_send_stdout(tmp, cnt);
+			count -= cnt;
+			buf += cnt;
+		}
+		return 0;
+	}
+#endif
+
 	if (t->tc->write == NULL)
 		return 0;
 	return t->tc->write(t->tc, fd, buf, count);

src/target/target_internal.h

@@ -129,6 +129,9 @@ struct target_s {
 	char cmdline[MAX_CMDLINE];
 	target_addr heapinfo[4];
 	struct target_command_s *commands;
+#ifdef PLATFORM_HAS_USBUART
+	bool stdout_redirected;
+#endif
 
 	struct target_s *next;