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Subject[PATCH v6 06/11] ARM: mvebu: Low level function to disable HW coherency support
Date
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>
---
arch/arm/mach-mvebu/coherency_ll.S | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/arch/arm/mach-mvebu/coherency_ll.S b/arch/arm/mach-mvebu/coherency_ll.S
index f2e2e8677c4b..6828f9f157b0 100644
--- a/arch/arm/mach-mvebu/coherency_ll.S
+++ b/arch/arm/mach-mvebu/coherency_ll.S
@@ -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:
--
1.8.1.2


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