console: Add console for GDB

Connection of UARTs to GDB stub got lost in the console transition
process, bring it back. In theory, GDB stub should work also over
usbdebug, but that solution is not really tested at all yet.

Change-Id: I90e05e8132889e788b92e055ee191f35add43bbc
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5343
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/arch/x86/lib/c_start.S

@@ -86,6 +86,7 @@ _start:
 	post_code(POST_PRE_HARDWAREMAIN)	/* post fe */
 
 #if CONFIG_GDB_WAIT
+	call gdb_hw_init
 	call gdb_stub_breakpoint
 #endif
 	call	main

src/arch/x86/lib/exception.c

@@ -1,4 +1,5 @@
 #include <console/console.h>
+#include <console/streams.h>
 #include <string.h>
 
 #if CONFIG_GDB_STUB
@@ -217,12 +218,17 @@ static char out_buffer[BUFMAX];
 
 static inline void stub_putc(int ch)
 {
-	console_tx_byte(ch);
+	gdb_tx_byte(ch);
+}
+
+static inline void stub_flush(void)
+{
+	gdb_tx_flush();
 }
 
 static inline int stub_getc(void)
 {
-	return console_rx_byte();
+	return gdb_rx_byte();
 }
 
 static int hex(char ch)
@@ -322,9 +328,11 @@ static int get_packet(char *buffer)
 
 			if (checksum != xmitcsum) {
 				stub_putc('-');	/* failed checksum */
+				stub_flush();
 			}
 			else {
 				stub_putc('+');	/* successful transfer */
+				stub_flush();
 			}
 		}
 	} while(checksum != xmitcsum);
@@ -353,6 +361,7 @@ static void put_packet(char *buffer)
 		stub_putc('#');
 		stub_putc(hexchars[checksum >> 4]);
 		stub_putc(hexchars[checksum % 16]);
+		stub_flush();
 
 	} while ((stub_getc() & 0x7f) != '+');
 

src/console/console.c

@@ -17,6 +17,7 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <rules.h>
 #include <console/streams.h>
 #include <console/cbmem_console.h>
 #include <console/uart.h>
@@ -53,3 +54,26 @@ void console_tx_flush(void)
 	__ne2k_tx_flush();
 	__usb_tx_flush();
 }
+
+
+#if CONFIG_GDB_STUB && (ENV_ROMSTAGE || ENV_RAMSTAGE)
+void gdb_hw_init(void)
+{
+	__gdb_hw_init();
+}
+
+void gdb_tx_byte(unsigned char byte)
+{
+	__gdb_tx_byte(byte);
+}
+
+void gdb_tx_flush(void)
+{
+	__gdb_tx_flush();
+}
+
+unsigned char gdb_rx_byte(void)
+{
+	return __gdb_rx_byte();
+}
+#endif

src/include/console/streams.h

@@ -22,6 +22,12 @@ void console_hw_init(void);
 void console_tx_byte(unsigned char byte);
 void console_tx_flush(void);
 
+/* For remote GDB debugging. */
+void gdb_hw_init(void);
+void gdb_tx_byte(unsigned char byte);
+void gdb_tx_flush(void);
+unsigned char gdb_rx_byte(void);
+
 /* Helpers for ROMCC console. */
 void console_tx_nibble(unsigned nibble);
 void console_tx_hex8(unsigned char value);

src/include/console/uart.h

@@ -69,6 +69,14 @@ static inline void __uart_tx_byte(u8 data)	{}
 static inline void __uart_tx_flush(void)	{}
 #endif
 
+#if CONFIG_GDB_STUB && (ENV_ROMSTAGE || ENV_RAMSTAGE)
+#define CONFIG_UART_FOR_GDB 	CONFIG_UART_FOR_CONSOLE
+static inline void __gdb_hw_init(void)	{ uart_init(CONFIG_UART_FOR_GDB); }
+static inline void __gdb_tx_byte(u8 data)	{ uart_tx_byte(CONFIG_UART_FOR_GDB, data); }
+static inline void __gdb_tx_flush(void)	{ uart_tx_flush(CONFIG_UART_FOR_GDB); }
+static inline u8 __gdb_rx_byte(void)		{ return uart_rx_byte(CONFIG_UART_FOR_GDB); }
+#endif
+
 #endif /* __ROMCC__ */
 
 #endif /* CONSOLE_UART_H */

src/include/console/usb.h

@@ -34,14 +34,26 @@ int usb_can_rx_byte(int idx);
 #define __CONSOLE_USB_ENABLE__	CONFIG_CONSOLE_USB && \
 	((ENV_ROMSTAGE && CONFIG_USBDEBUG_IN_ROMSTAGE) || ENV_RAMSTAGE)
 
+#define USB_PIPE_FOR_CONSOLE 0
+#define USB_PIPE_FOR_GDB 0
+
 #if __CONSOLE_USB_ENABLE__
 static inline void __usbdebug_init(void)	{ usbdebug_init(); }
-static inline void __usb_tx_byte(u8 data)	{ usb_tx_byte(0, data); }
-static inline void __usb_tx_flush(void)	{ usb_tx_flush(0); }
+static inline void __usb_tx_byte(u8 data)	{ usb_tx_byte(USB_PIPE_FOR_CONSOLE, data); }
+static inline void __usb_tx_flush(void)	{ usb_tx_flush(USB_PIPE_FOR_CONSOLE); }
 #else
 static inline void __usbdebug_init(void)	{}
 static inline void __usb_tx_byte(u8 data)	{}
 static inline void __usb_tx_flush(void)	{}
 #endif
 
+/*  */
+#if 0 && CONFIG_GDB_STUB && \
+	((ENV_ROMSTAGE && CONFIG_USBDEBUG_IN_ROMSTAGE) || ENV_RAMSTAGE)
+static inline void __gdb_hw_init(void)	{ usbdebug_init(); }
+static inline void __gdb_tx_byte(u8 data)	{ usb_tx_byte(USB_PIPE_FOR_GDB, data); }
+static inline void __gdb_tx_flush(void)	{ usb_tx_flush(USB_PIPE_FOR_GDB); }
+static inline u8 __gdb_rx_byte(void)		{ return usb_rx_byte(USB_PIPE_FOR_GDB); }
+#endif
+
 #endif /* _CONSOLE_USB_H_ */