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ARM: 8389/1: Add cpu_resume_arm() for firmwares that resume in ARM state

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Some platforms always enter the kernel in the ARM state even if
the kernel is compiled for THUMB2. Add a small wrapper on top of
cpu_resume() that switches into THUMB2 state.

This provides the functionality to fix a problem reported by Kevin
Hilman on next-20150601 where the ifc6410 fails to boot a THUMB2
kernel because the platform's firmware always enters the kernel in
ARM mode from deep idle states.

(rmk: tweaked to work without BSYM->badr changes.)

Reported-by: Kevin Hilman <khilman@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Stephen Boyd 2015-06-09 19:24:23 +01:00 committed by Russell King
parent 02b4e2756e
commit 32e55a777f
2 changed files with 8 additions and 0 deletions
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1
arch/arm/include/asm/suspend.h
View File

@ -7,6 +7,7 @@ struct sleep_save_sp {
};
extern void cpu_resume(void);
extern void cpu_resume_arm(void);
extern int cpu_suspend(unsigned long, int (*)(unsigned long));
#endif

7
arch/arm/kernel/sleep.S
View File

@ -118,6 +118,12 @@ ENDPROC(cpu_resume_after_mmu)
.text
.align
.arm
ENTRY(cpu_resume_arm)
THUMB( adr r9, BSYM(1f) ) @ Kernel is entered in ARM.
THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
THUMB( .thumb ) @ switch to Thumb now.
THUMB(1: )
ENTRY(cpu_resume)
ARM_BE8(setend be) @ ensure we are in BE mode
#ifdef CONFIG_ARM_VIRT_EXT
@ -149,6 +155,7 @@ THUMB( ldmia r0!, {r1, r2, r3} )
THUMB( mov sp, r2 )
THUMB( bx r3 )
ENDPROC(cpu_resume)
ENDPROC(cpu_resume_arm)
.align 2
_sleep_save_sp: