xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ARM: 7338/1: add support for early console output via semihosting

Browse Source 
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>
This commit is contained in:
Nicolas Pitre
2012-02-22 21:58:03 +01:00
committed by Russell King
parent 101d9b0ded
commit 9b5a146a43
3 changed files with 44 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
arch/arm/kernel/debug.S
View File

@@ -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 @@ hexbuf: .space 16
.ltorg
#ifndef CONFIG_DEBUG_SEMIHOSTING
ENTRY(printascii)
addruart_current r3, r1, r2
b 2f
@@ -177,3 +179,24 @@ ENTRY(printch)
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

8
arch/arm/kernel/head.S
View File

@@ -265,7 +265,7 @@ __create_page_tables:
str r6, [r3]
#ifdef CONFIG_DEBUG_LL
#ifndef CONFIG_DEBUG_ICEDCC
#if !defined(CONFIG_DEBUG_ICEDCC) && !defined(CONFIG_DEBUG_SEMIHOSTING)
/*
* Map in IO space for serial debugging.
* This allows debug messages to be output
@@ -297,10 +297,10 @@ __create_page_tables:
cmp r0, r6
blo 1b
#else /* CONFIG_DEBUG_ICEDCC */
/* we don't need any serial debugging mappings for ICEDCC */
#else /* CONFIG_DEBUG_ICEDCC || CONFIG_DEBUG_SEMIHOSTING */
/* we don't need any serial debugging mappings */
ldr r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
#endif /* !CONFIG_DEBUG_ICEDCC */
#endif
#if defined(CONFIG_ARCH_NETWINDER) || defined(CONFIG_ARCH_CATS)
/*