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Commit 2cc4cc28 authored by Patrick Daly's avatar Patrick Daly
Browse files

iommu/dma: Allow drivers to reserve an iova range 



Some devices have a memory map which contains gaps or holes. In order for
the device to have as much iova space as possible, allow its driver to
inform the dma-iommu that it should not allocate addresses from these
holes.

Change-Id: I029d50c1f1e84ece48de30ef21b63cac8fe05257
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent 9e9032d1

drivers/iommu/dma-iommu.c

+25 −0
Original line number Diff line number Diff line
@@ -316,6 +316,31 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, 
}

EXPORT_SYMBOL(iommu_dma_init_domain);



/*

 * Should be called prior to using dma-apis

 */

int iommu_dma_reserve_iova(struct device *dev, dma_addr_t base,

			   u64 size)

{

	struct iommu_domain *domain;

	struct iova_domain *iovad;

	unsigned long pfn_lo, pfn_hi;



	domain = iommu_get_domain_for_dev(dev);

	if (!domain || !domain->iova_cookie)

		return -EINVAL;



	iovad = &((struct iommu_dma_cookie *)domain->iova_cookie)->iovad;



	/* iova will be freed automatically by put_iova_domain() */

	pfn_lo = iova_pfn(iovad, base);

	pfn_hi = iova_pfn(iovad, base + size - 1);

	if (!reserve_iova(iovad, pfn_lo, pfn_hi))

		return -EINVAL;



	return 0;

}



/**

 * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API

 *                    page flags.

include/linux/dma-iommu.h

+9 −0
Original line number Diff line number Diff line
@@ -82,6 +82,9 @@ int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr); 
void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg);

void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list);



int iommu_dma_reserve_iova(struct device *dev, dma_addr_t base,

			   u64 size);



#else



struct iommu_domain;
@@ -115,6 +118,12 @@ static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_he 
{

}



static inline int iommu_dma_reserve_iova(struct device *dev, dma_addr_t base,

					 u64 size)

{

	return -ENODEV;

}



#endif	/* CONFIG_IOMMU_DMA */

#endif	/* __KERNEL__ */

#endif	/* __DMA_IOMMU_H */