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Commit f1ae98da authored by Marek Szyprowski's avatar Marek Szyprowski
Browse files

ARM: dma-mapping: remove unconditional dependency on CMA 



CMA has been enabled unconditionally on all ARMv6+ systems to solve the
long standing issue of double kernel mappings for all dma coherent
buffers. This however created a dependency on CONFIG_EXPERIMENTAL for
the whole ARM architecture what should be really avoided. This patch
removes this dependency and lets one use old, well-tested dma-mapping
implementation also on ARMv6+ systems without the need to use
EXPERIMENTAL stuff.

Reported-by: default avatarRussell King <linux@arm.linux.org.uk>
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
parent f8f5701b

arch/arm/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ config ARM 
	select HAVE_IDE if PCI || ISA || PCMCIA

	select HAVE_DMA_ATTRS

	select HAVE_DMA_CONTIGUOUS if (CPU_V6 || CPU_V6K || CPU_V7)

	select CMA if (CPU_V6 || CPU_V6K || CPU_V7)

	select HAVE_MEMBLOCK

	select RTC_LIB

	select SYS_SUPPORTS_APM_EMULATION

arch/arm/mm/dma-mapping.c

+4 −6
Original line number Diff line number Diff line
@@ -268,10 +268,8 @@ static int __init consistent_init(void) 
	unsigned long base = consistent_base;

	unsigned long num_ptes = (CONSISTENT_END - base) >> PMD_SHIFT;



#ifndef CONFIG_ARM_DMA_USE_IOMMU

	if (cpu_architecture() >= CPU_ARCH_ARMv6)

	if (IS_ENABLED(CONFIG_CMA) && !IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))

		return 0;

#endif



	consistent_pte = kmalloc(num_ptes * sizeof(pte_t), GFP_KERNEL);

	if (!consistent_pte) {
@@ -342,7 +340,7 @@ static int __init coherent_init(void) 
	struct page *page;

	void *ptr;



	if (cpu_architecture() < CPU_ARCH_ARMv6)

	if (!IS_ENABLED(CONFIG_CMA))

		return 0;



	ptr = __alloc_from_contiguous(NULL, size, prot, &page);
@@ -704,7 +702,7 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, 


	if (arch_is_coherent() || nommu())

		addr = __alloc_simple_buffer(dev, size, gfp, &page);

	else if (cpu_architecture() < CPU_ARCH_ARMv6)

	else if (!IS_ENABLED(CONFIG_CMA))

		addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);

	else if (gfp & GFP_ATOMIC)

		addr = __alloc_from_pool(dev, size, &page, caller);
@@ -773,7 +771,7 @@ void arm_dma_free(struct device *dev, size_t size, void *cpu_addr, 


	if (arch_is_coherent() || nommu()) {

		__dma_free_buffer(page, size);

	} else if (cpu_architecture() < CPU_ARCH_ARMv6) {

	} else if (!IS_ENABLED(CONFIG_CMA)) {

		__dma_free_remap(cpu_addr, size);

		__dma_free_buffer(page, size);

	} else {