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Commit 741f92f5 authored by Liam Mark's avatar Liam Mark Committed by Todd Kjos
Browse files

FROMLIST: 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 layer that it should
not allocate addresses from these holes.

Bug: 149544395
Link: https://lore.kernel.org/lkml/20200220185728.GA32137@pratikp-lnx/


Change-Id: I15bd1d313d889c2572d0eb2adecf6bebde3267f7
Signed-off-by: default avatarIsaac J. Manjarres <isaacm@codeaurora.org>
parent 15b06f49

drivers/iommu/dma-iommu.c

+28 −0
Original line number Diff line number Diff line
@@ -352,6 +352,34 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, 
	return iova_reserve_iommu_regions(dev, 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 iommu_dma_cookie *cookie;

	struct iova_domain *iovad;

	unsigned long pfn_lo, pfn_hi;



	domain = iommu_get_domain_for_dev(dev);

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

		return -EINVAL;



	cookie = domain->iova_cookie;

	iovad = &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;

}

EXPORT_SYMBOL(iommu_dma_reserve_iova);



/**

 * 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
@@ -37,6 +37,9 @@ void iommu_dma_compose_msi_msg(struct msi_desc *desc, 


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 /* CONFIG_IOMMU_DMA */



struct iommu_domain;
@@ -78,5 +81,11 @@ 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	/* __DMA_IOMMU_H */