ARM: 7338/1: add support for early console output via semihosting
This is a very simple method for code running in an emulator, or under
the supervision of a debugger, to use I/O facilities on the controlling
host.
Tested with OpenOCD, and ARM's Fast Models.
Details on semihosting can be found in chapter 8 of
DUI0203I_rvct_developer_guide.pdf from ARM Ltd.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S
index 204e216..e5a765c 100644
--- a/arch/arm/kernel/debug.S
+++ b/arch/arm/kernel/debug.S
@@ -100,7 +100,7 @@
#endif /* CONFIG_CPU_V6 */
-#else
+#elif !defined(CONFIG_DEBUG_SEMIHOSTING)
#include <mach/debug-macro.S>
#endif /* CONFIG_DEBUG_ICEDCC */
@@ -155,6 +155,8 @@
.ltorg
+#ifndef CONFIG_DEBUG_SEMIHOSTING
+
ENTRY(printascii)
addruart_current r3, r1, r2
b 2f
@@ -177,3 +179,24 @@
mov r0, #0
b 1b
ENDPROC(printch)
+
+#else
+
+ENTRY(printascii)
+ mov r1, r0
+ mov r0, #0x04 @ SYS_WRITE0
+ ARM( svc #0x123456 )
+ THUMB( svc #0xab )
+ mov pc, lr
+ENDPROC(printascii)
+
+ENTRY(printch)
+ adr r1, hexbuf
+ strb r0, [r1]
+ mov r0, #0x03 @ SYS_WRITEC
+ ARM( svc #0x123456 )
+ THUMB( svc #0xab )
+ mov pc, lr
+ENDPROC(printch)
+
+#endif
