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MIPS: Loongson 2F: Fix of problems introduced by -mfix-loongson2f-jump 

The -mfix-loongson2f-jump option provided by latest CVS binutils have fixed
the out-of-order issue of Loongson-2F described in chapter 15 of the
Loongson2F User Manual [1, 2], but introduced some problems.

The option changes all of the jump target to "addr & 0xcfffffff" through the
at($1) register, but for the reboot address of Loongson 2F 0xbfc00000 this is
wrong.  Avoids the problem via telling the assembler to not use the $at
register.

[1] Loongson2F User Manual (Chinese Version)
    http://www.loongson.cn/uploadfile/file/200808211
[2] English Version of Chapter 15:
    http://groups.google.com.hk/group/loongson-dev/msg/e0d2e220958f10a6?dmode=source

Reported-and-tested-by: Liu Shiwei <liushiwei@gmail.com>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/1109/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Wu Zhangjin 2010-04-10 20:07:13 +08:00 committed by Ralf Baechle
parent b197b62866
commit 64fc74f5f6
1 changed files with 19 additions and 1 deletions
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20
arch/mips/loongson/common/reset.c
View File

@ -16,13 +16,31 @@
#include <loongson.h>
static inline void loongson_reboot(void)
{
#ifndef CONFIG_CPU_JUMP_WORKAROUNDS
((void (*)(void))ioremap_nocache(LOONGSON_BOOT_BASE, 4)) ();
#else
void (*func)(void);
func = (void *)ioremap_nocache(LOONGSON_BOOT_BASE, 4);
__asm__ __volatile__(
" .set noat \n"
" jr %[func] \n"
" .set at \n"
: /* No outputs */
: [func] "r" (func));
#endif
}
static void loongson_restart(char *command)
{
/* do preparation for reboot */
mach_prepare_reboot();
/* reboot via jumping to boot base address */
((void (*)(void))ioremap_nocache(LOONGSON_BOOT_BASE, 4)) ();
loongson_reboot();
}
static void loongson_poweroff(void)