Commit f4d6477f authored by Catalin Marinas's avatar Catalin Marinas Committed by Russell King
Browse files

ARM: 6111/1: Implement read/write for ownership in the ARMv6 DMA cache ops 



The Snoop Control Unit on the ARM11MPCore hardware does not detect the
cache operations and the dma_cache_maint*() functions may leave stale
cache entries on other CPUs. The solution implemented in this patch
performs a Read or Write For Ownership in the ARMv6 DMA cache
maintenance functions. These LDR/STR instructions change the cache line
state to shared or exclusive so that the cache maintenance operation has
the desired effect.

Tested-by: default avatarGeorge G. Davis <gdavis@mvista.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent b5a07faa

arch/arm/mm/cache-v6.S

+13 −4
Original line number Diff line number Diff line
@@ -211,6 +211,9 @@ v6_dma_inv_range: 
	mcrne	p15, 0, r1, c7, c15, 1		@ clean & invalidate unified line

#endif

1:

#ifdef CONFIG_SMP

	str	r0, [r0]			@ write for ownership

#endif

#ifdef HARVARD_CACHE

	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D line

#else
@@ -231,6 +234,9 @@ v6_dma_inv_range: 
v6_dma_clean_range:

	bic	r0, r0, #D_CACHE_LINE_SIZE - 1

1:

#ifdef CONFIG_SMP

	ldr	r2, [r0]			@ read for ownership

#endif

#ifdef HARVARD_CACHE

	mcr	p15, 0, r0, c7, c10, 1		@ clean D line

#else
@@ -251,6 +257,10 @@ v6_dma_clean_range: 
ENTRY(v6_dma_flush_range)

	bic	r0, r0, #D_CACHE_LINE_SIZE - 1

1:

#ifdef CONFIG_SMP

	ldr	r2, [r0]			@ read for ownership

	str	r2, [r0]			@ write for ownership

#endif

#ifdef HARVARD_CACHE

	mcr	p15, 0, r0, c7, c14, 1		@ clean & invalidate D line

#else
@@ -273,7 +283,9 @@ ENTRY(v6_dma_map_area) 
	add	r1, r1, r0

	teq	r2, #DMA_FROM_DEVICE

	beq	v6_dma_inv_range

	b	v6_dma_clean_range

	teq	r2, #DMA_TO_DEVICE

	beq	v6_dma_clean_range

	b	v6_dma_flush_range

ENDPROC(v6_dma_map_area)



/*
@@ -283,9 +295,6 @@ ENDPROC(v6_dma_map_area) 
 *	- dir	- DMA direction

 */

ENTRY(v6_dma_unmap_area)

	add	r1, r1, r0

	teq	r2, #DMA_TO_DEVICE

	bne	v6_dma_inv_range

	mov	pc, lr

ENDPROC(v6_dma_unmap_area)

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