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

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 <[email protected]> Link: https://lkml.kernel.org/r/1397488214-20685-7-git-send-email-gregory.clement@free-electrons.com Signed-off-by: Jason Cooper <[email protected]>
rtvt123 · May 8, 2014 · 1a6bfbc · 1a6bfbc
1 parent 2e8a594
commit 1a6bfbc
Showing 1 changed file with 20 additions and 0 deletions.
diff --git 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: