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x86: enable DMA CMA with swiotlb

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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: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Konrad 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2014-06-04 16:06:50 -07:00 committed by Linus Torvalds
parent d92ef66c4f
commit 9c5a362142
7 changed files with 20 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/Kconfig
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@ -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

7
arch/x86/include/asm/swiotlb.h
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@ -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 */

2
arch/x86/kernel/amd_gart_64.c
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@ -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)

9
arch/x86/kernel/pci-swiotlb.c
View File

@ -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)
{
swiotlb_free_coherent(dev, size, vaddr, dma_addr);
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 = {

6
arch/x86/pci/sta2x11-fixup.c
View File

@ -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,

2
include/linux/swiotlb.h
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@ -116,4 +116,6 @@ static inline void swiotlb_free(void) { }
#endif
extern void swiotlb_print_info(void);
extern int is_swiotlb_buffer(phys_addr_t paddr);
#endif /* __LINUX_SWIOTLB_H */

2
lib/swiotlb.c
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@ -374,7 +374,7 @@ void __init swiotlb_free(void)
io_tlb_nslabs = 0;
}
static int is_swiotlb_buffer(phys_addr_t paddr)
int is_swiotlb_buffer(phys_addr_t paddr)
{
return paddr >= io_tlb_start && paddr < io_tlb_end;
}