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linux-next/arch/arm/kernel/debug.S
Rob Herring e5c5f2adeb ARM: implement debug_ll_io_init()
When using DEBUG_LL, the UART's (or other HW's) registers are mapped
into early page tables based on the results of assembly macro addruart.
Later, when the page tables are replaced, the same virtual address must
remain valid. Historically, this has been ensured by using defines from
<mach/iomap.h> in both the implementation of addruart, and the machine's
.map_io() function. However, with the move to single zImage, we wish to
remove <mach/iomap.h>. To enable this, the macro addruart may be used
when constructing the late page tables too; addruart is exposed as a
C function debug_ll_addr(), and used to set up the required mapping in
debug_ll_io_init(), which may called on an opt-in basis from a machine's
.map_io() function.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
[swarren: Mask map.virtual with PAGE_MASK. Checked for NULL results from
 debug_ll_addr (e.g. when selected UART isn't valid). Fixed compile when
 either !CONFIG_DEBUG_LL or CONFIG_DEBUG_SEMIHOSTING.]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
2012-11-05 09:35:59 -08:00

137 lines
2.3 KiB
ArmAsm

/*
* linux/arch/arm/kernel/debug.S
*
* Copyright (C) 1994-1999 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 32-bit debugging code
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.text
/*
* Some debugging routines (useful if you've got MM problems and
* printk isn't working). For DEBUGGING ONLY!!! Do not leave
* references to these in a production kernel!
*/
#if !defined(CONFIG_DEBUG_SEMIHOSTING)
#include CONFIG_DEBUG_LL_INCLUDE
#endif
#ifdef CONFIG_MMU
.macro addruart_current, rx, tmp1, tmp2
addruart \tmp1, \tmp2, \rx
mrc p15, 0, \rx, c1, c0
tst \rx, #1
moveq \rx, \tmp1
movne \rx, \tmp2
.endm
#else /* !CONFIG_MMU */
.macro addruart_current, rx, tmp1, tmp2
addruart \rx, \tmp1
.endm
#endif /* CONFIG_MMU */
/*
* Useful debugging routines
*/
ENTRY(printhex8)
mov r1, #8
b printhex
ENDPROC(printhex8)
ENTRY(printhex4)
mov r1, #4
b printhex
ENDPROC(printhex4)
ENTRY(printhex2)
mov r1, #2
printhex: adr r2, hexbuf
add r3, r2, r1
mov r1, #0
strb r1, [r3]
1: and r1, r0, #15
mov r0, r0, lsr #4
cmp r1, #10
addlt r1, r1, #'0'
addge r1, r1, #'a' - 10
strb r1, [r3, #-1]!
teq r3, r2
bne 1b
mov r0, r2
b printascii
ENDPROC(printhex2)
hexbuf: .space 16
.ltorg
#ifndef CONFIG_DEBUG_SEMIHOSTING
ENTRY(printascii)
addruart_current r3, r1, r2
b 2f
1: waituart r2, r3
senduart r1, r3
busyuart r2, r3
teq r1, #'\n'
moveq r1, #'\r'
beq 1b
2: teq r0, #0
ldrneb r1, [r0], #1
teqne r1, #0
bne 1b
mov pc, lr
ENDPROC(printascii)
ENTRY(printch)
addruart_current r3, r1, r2
mov r1, r0
mov r0, #0
b 1b
ENDPROC(printch)
ENTRY(debug_ll_addr)
addruart r2, r3, ip
str r2, [r0]
str r3, [r1]
mov pc, lr
ENDPROC(debug_ll_addr)
#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)
ENTRY(debug_ll_addr)
mov r2, #0
str r2, [r0]
str r2, [r1]
mov pc, lr
ENDPROC(debug_ll_addr)
#endif