Commit 9c5a3621 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
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x86: enable DMA CMA with swiotlb 



The DMA Contiguous Memory Allocator support on x86 is disabled when
swiotlb config option is enabled.  So DMA CMA is always disabled on
x86_64 because swiotlb is always enabled.  This attempts to support for
DMA CMA with enabling swiotlb config option.

The contiguous memory allocator on x86 is integrated in the function
dma_generic_alloc_coherent() which is .alloc callback in nommu_dma_ops
for dma_alloc_coherent().

x86_swiotlb_alloc_coherent() which is .alloc callback in swiotlb_dma_ops
tries to allocate with dma_generic_alloc_coherent() firstly and then
swiotlb_alloc_coherent() is called as a fallback.

The main part of supporting DMA CMA with swiotlb is that changing
x86_swiotlb_free_coherent() which is .free callback in swiotlb_dma_ops
for dma_free_coherent() so that it can distinguish memory allocated by
dma_generic_alloc_coherent() from one allocated by
swiotlb_alloc_coherent() and release it with dma_generic_free_coherent()
which can handle contiguous memory.  This change requires making
is_swiotlb_buffer() global function.

This also needs to change .free callback in the dma_map_ops for amd_gart
and sta2x11, because these dma_ops are also using
dma_generic_alloc_coherent().

Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d92ef66c

arch/x86/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ config X86 
	select ARCH_WANT_OPTIONAL_GPIOLIB

	select ARCH_WANT_FRAME_POINTERS

	select HAVE_DMA_ATTRS

	select HAVE_DMA_CONTIGUOUS if !SWIOTLB

	select HAVE_DMA_CONTIGUOUS

	select HAVE_KRETPROBES

	select GENERIC_EARLY_IOREMAP

	select HAVE_OPTPROBES

arch/x86/include/asm/swiotlb.h

+7 −0
Original line number Diff line number Diff line
@@ -29,4 +29,11 @@ static inline void pci_swiotlb_late_init(void) 


static inline void dma_mark_clean(void *addr, size_t size) {}



extern void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,

					dma_addr_t *dma_handle, gfp_t flags,

					struct dma_attrs *attrs);

extern void x86_swiotlb_free_coherent(struct device *dev, size_t size,

					void *vaddr, dma_addr_t dma_addr,

					struct dma_attrs *attrs);



#endif /* _ASM_X86_SWIOTLB_H */

arch/x86/kernel/amd_gart_64.c

+1 −1
Original line number Diff line number Diff line
@@ -512,7 +512,7 @@ gart_free_coherent(struct device *dev, size_t size, void *vaddr, 
		   dma_addr_t dma_addr, struct dma_attrs *attrs)

{

	gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, NULL);

	free_pages((unsigned long)vaddr, get_order(size));

	dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);

}



static int gart_mapping_error(struct device *dev, dma_addr_t dma_addr)

arch/x86/kernel/pci-swiotlb.c

+6 −3
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ 
#include <asm/iommu_table.h>

int swiotlb __read_mostly;



static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,

void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,

					dma_addr_t *dma_handle, gfp_t flags,

					struct dma_attrs *attrs)

{
@@ -28,11 +28,14 @@ static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size, 
	return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);

}



static void x86_swiotlb_free_coherent(struct device *dev, size_t size,

void x86_swiotlb_free_coherent(struct device *dev, size_t size,

				      void *vaddr, dma_addr_t dma_addr,

				      struct dma_attrs *attrs)

{

	if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))

		swiotlb_free_coherent(dev, size, vaddr, dma_addr);

	else

		dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);

}



static struct dma_map_ops swiotlb_dma_ops = {

arch/x86/pci/sta2x11-fixup.c

+2 −4
Original line number Diff line number Diff line
@@ -173,9 +173,7 @@ static void *sta2x11_swiotlb_alloc_coherent(struct device *dev, 
{

	void *vaddr;



	vaddr = dma_generic_alloc_coherent(dev, size, dma_handle, flags, attrs);

	if (!vaddr)

		vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, flags);

	vaddr = x86_swiotlb_alloc_coherent(dev, size, dma_handle, flags, attrs);

	*dma_handle = p2a(*dma_handle, to_pci_dev(dev));

	return vaddr;

}
@@ -183,7 +181,7 @@ static void *sta2x11_swiotlb_alloc_coherent(struct device *dev, 
/* We have our own dma_ops: the same as swiotlb but from alloc (above) */

static struct dma_map_ops sta2x11_dma_ops = {

	.alloc = sta2x11_swiotlb_alloc_coherent,

	.free = swiotlb_free_coherent,

	.free = x86_swiotlb_free_coherent,

	.map_page = swiotlb_map_page,

	.unmap_page = swiotlb_unmap_page,

	.map_sg = swiotlb_map_sg_attrs,

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