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ARM: mvebu: Low level function to disable HW coherency support

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When going to deep idle we need to disable the SoC snooping (aka
hardware coherency support). Playing with the coherency fabric
requires to use assembly code to be sure that the compiler doesn't
reorder the instructions nor do wrong optimization.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1397488214-20685-7-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
This commit is contained in:
Gregory CLEMENT 2014-04-14 17:10:09 +02:00 committed by Jason Cooper
parent 2e8a5942f8
commit 1a6bfbc339
1 changed files with 20 additions and 0 deletions
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20
arch/arm/mach-mvebu/coherency_ll.S
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@ -102,6 +102,26 @@ ENTRY(ll_enable_coherency)
mov pc, lr
ENDPROC(ll_enable_coherency)
ENTRY(ll_disable_coherency)
/*
* r0 being untouched in ll_get_coherency_base and
* ll_get_cpuid, we can use it to save lr modifing it with the
* following bl
*/
mov r0, lr
bl ll_get_coherency_base
bl ll_get_cpuid
mov lr, r0
add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET
1:
ldrex r2, [r0]
bic r2, r2, r3
strex r1, r2, [r0]
cmp r1, #0
bne 1b
dsb
mov pc, lr
ENDPROC(ll_disable_coherency)
.align 2
3: