Commit 7423e017 authored by Lu Baolu's avatar Lu Baolu Committed by Joerg Roedel
Browse files

iommu: Add API to request DMA domain for device 



Normally during iommu probing a device, a default doamin will
be allocated and attached to the device. The domain type of
the default domain is statically defined, which results in a
situation where the allocated default domain isn't suitable
for the device due to some limitations. We already have API
iommu_request_dm_for_dev() to replace a DMA domain with an
identity one. This adds iommu_request_dma_domain_for_dev()
to request a dma domain if an allocated identity domain isn't
suitable for the device in question.

Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent dd5142ca

drivers/iommu/iommu.c

+25 −11
Original line number Diff line number Diff line
@@ -1907,10 +1907,10 @@ struct iommu_resv_region *iommu_alloc_resv_region(phys_addr_t start, 
	return region;

}



/* Request that a device is direct mapped by the IOMMU */

int iommu_request_dm_for_dev(struct device *dev)

static int

request_default_domain_for_dev(struct device *dev, unsigned long type)

{

	struct iommu_domain *dm_domain;

	struct iommu_domain *domain;

	struct iommu_group *group;

	int ret;
@@ -1923,8 +1923,7 @@ int iommu_request_dm_for_dev(struct device *dev) 


	/* Check if the default domain is already direct mapped */

	ret = 0;

	if (group->default_domain &&

	    group->default_domain->type == IOMMU_DOMAIN_IDENTITY)

	if (group->default_domain && group->default_domain->type == type)

		goto out;



	/* Don't change mappings of existing devices */
@@ -1934,23 +1933,26 @@ int iommu_request_dm_for_dev(struct device *dev) 


	/* Allocate a direct mapped domain */

	ret = -ENOMEM;

	dm_domain = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_IDENTITY);

	if (!dm_domain)

	domain = __iommu_domain_alloc(dev->bus, type);

	if (!domain)

		goto out;



	/* Attach the device to the domain */

	ret = __iommu_attach_group(dm_domain, group);

	ret = __iommu_attach_group(domain, group);

	if (ret) {

		iommu_domain_free(dm_domain);

		iommu_domain_free(domain);

		goto out;

	}



	iommu_group_create_direct_mappings(group, dev);



	/* Make the direct mapped domain the default for this group */

	if (group->default_domain)

		iommu_domain_free(group->default_domain);

	group->default_domain = dm_domain;

	group->default_domain = domain;



	dev_info(dev, "Using iommu direct mapping\n");

	dev_info(dev, "Using iommu %s mapping\n",

		 type == IOMMU_DOMAIN_DMA ? "dma" : "direct");



	ret = 0;

out:
@@ -1960,6 +1962,18 @@ out: 
	return ret;

}



/* Request that a device is direct mapped by the IOMMU */

int iommu_request_dm_for_dev(struct device *dev)

{

	return request_default_domain_for_dev(dev, IOMMU_DOMAIN_IDENTITY);

}



/* Request that a device can't be direct mapped by the IOMMU */

int iommu_request_dma_domain_for_dev(struct device *dev)

{

	return request_default_domain_for_dev(dev, IOMMU_DOMAIN_DMA);

}



const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)

{

	const struct iommu_ops *ops = NULL;

include/linux/iommu.h

+6 −0
Original line number Diff line number Diff line
@@ -362,6 +362,7 @@ extern void iommu_set_fault_handler(struct iommu_domain *domain, 
extern void iommu_get_resv_regions(struct device *dev, struct list_head *list);

extern void iommu_put_resv_regions(struct device *dev, struct list_head *list);

extern int iommu_request_dm_for_dev(struct device *dev);

extern int iommu_request_dma_domain_for_dev(struct device *dev);

extern struct iommu_resv_region *

iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot,

			enum iommu_resv_type type);
@@ -626,6 +627,11 @@ static inline int iommu_request_dm_for_dev(struct device *dev) 
	return -ENODEV;

}



static inline int iommu_request_dma_domain_for_dev(struct device *dev)

{

	return -ENODEV;

}



static inline int iommu_attach_group(struct iommu_domain *domain,

				     struct iommu_group *group)

{

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