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Commit f0dbb6af authored by Patrick Daly's avatar Patrick Daly
Browse files

arm64: dma-mapping: add support for IOMMU mapper 



On systems with IOMMUs, it's useful to handle IOMMU mappings in the
dma-mapping layer. This is currently supported on arm but not arm64. Add
support in arm64 by gratuitously lifting most of the IOMMU-related stuff
from dma-mapping.c in arm.

The original arm work was done by Marek Szyprowski in [4ce63fcd:
"ARM: dma-mapping: add support for IOMMU mapper"].

Change-Id: I1c3c8fe15049fe456751074398fd179ebd2ec64e
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent cc3ff310

arch/arm64/Kconfig

+26 −0
Original line number Diff line number Diff line
@@ -219,6 +219,32 @@ config NEED_SG_DMA_LENGTH 
config SMP

	def_bool y



config ARM64_DMA_USE_IOMMU

	bool

	select ARM_HAS_SG_CHAIN

	select NEED_SG_DMA_LENGTH



if ARM64_DMA_USE_IOMMU



config ARM64_DMA_IOMMU_ALIGNMENT

	int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers"

	range 4 9

	default 8

	help

	  DMA mapping framework by default aligns all buffers to the smallest

	  PAGE_SIZE order which is greater than or equal to the requested buffer

	  size. This works well for buffers up to a few hundreds kilobytes, but

	  for larger buffers it just a waste of address space. Drivers which has

	  relatively small addressing window (like 64Mib) might run out of

	  virtual space with just a few allocations.



	  With this parameter you can specify the maximum PAGE_SIZE order for

	  DMA IOMMU buffers. Larger buffers will be aligned only to this

	  specified order. The order is expressed as a power of two multiplied

	  by the PAGE_SIZE.



endif



config SWIOTLB

	def_bool y

arch/arm64/include/asm/device.h

+9 −0
Original line number Diff line number Diff line
@@ -22,10 +22,19 @@ struct dev_archdata { 
	void *iommu;			/* private IOMMU data */

#endif

	bool dma_coherent;

#ifdef CONFIG_ARM64_DMA_USE_IOMMU

	struct dma_iommu_mapping	*mapping;

#endif

};



struct pdev_archdata {

	u64 dma_mask;

};



#ifdef CONFIG_ARM64_DMA_USE_IOMMU

#define to_dma_iommu_mapping(dev) ((dev)->archdata.mapping)

#else

#define to_dma_iommu_mapping(dev) NULL

#endif



#endif

arch/arm64/include/asm/dma-iommu.h

0 → 100644
+36 −0
Original line number Diff line number Diff line 
#ifndef ASMARM_DMA_IOMMU_H

#define ASMARM_DMA_IOMMU_H



#ifdef __KERNEL__



#include <linux/mm_types.h>

#include <linux/scatterlist.h>

#include <linux/dma-debug.h>

#include <linux/kmemcheck.h>

#include <linux/kref.h>



struct dma_iommu_mapping {

	/* iommu specific data */

	struct iommu_domain	*domain;



	void			*bitmap;

	size_t			bits;

	unsigned int		order;

	dma_addr_t		base;



	spinlock_t		lock;

	struct kref		kref;

};



struct dma_iommu_mapping *

arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,

			 int order);



void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);



int arm_iommu_attach_device(struct device *dev,

					struct dma_iommu_mapping *mapping);

void arm_iommu_detach_device(struct device *dev);



#endif /* __KERNEL__ */

#endif

arch/arm64/mm/dma-mapping.c

+973 −0

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