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Commit 0980131b authored by Patrick Daly's avatar Patrick Daly
Browse files

iommu: arm-smmu: Disable default DMA Domain support 



The current upstream arm-smmu implementation supports a 'stub' default DMA
domain. This domain is automatically attached at bootup, but has no context
bank or stream-ids. A device may choose to attach a different domain with
other context bank/stream-id settings. When the device detaches from this
domain, the 'default domain' is again attached automatically. This behavior
conflicts with several qcom-added features.

Dynamic domains:

When a dynamic domain is detached, the stream-ids of the dynamic domain
must not be removed.

Power:

Qcom uses the attach_dev() and detach_dev() callbacks as a signal that
power to the iommu can be removed. But with a default domain, the iommu is
always attached.

Change-Id: I84ec42667b986e5abfdbb0b5b7956a38532cabaa
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent c190d93b

drivers/iommu/arm-smmu.c

+21 −5
Original line number Diff line number Diff line
@@ -1313,7 +1313,8 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) 
{

	struct arm_smmu_domain *smmu_domain;



	if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)

	/* Do not support DOMAIN_DMA for now */

	if (type != IOMMU_DOMAIN_UNMANAGED)

		return NULL;

	/*

	 * Allocate the domain and initialise some of its data structures.
@@ -1483,11 +1484,25 @@ static void arm_smmu_domain_remove_master(struct arm_smmu_domain *smmu_domain, 
	arm_smmu_master_free_smrs(smmu, cfg);

}



static void arm_smmu_detach_dev(struct device *dev,

				struct arm_smmu_master_cfg *cfg)

static void arm_smmu_detach_dev(struct iommu_domain *domain,

				struct device *dev)

{

	struct iommu_domain *domain = dev->archdata.iommu;

	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

	struct arm_smmu_device *smmu = smmu_domain->smmu;

	struct arm_smmu_master_cfg *cfg;

	int dynamic = smmu_domain->attributes & (1 << DOMAIN_ATTR_DYNAMIC);



	if (dynamic)

		return;



	cfg = find_smmu_master_cfg(dev);

	if (!cfg)

		return;



	if (!smmu) {

		dev_err(dev, "Domain not attached; cannot detach!\n");

		return;

	}



	dev->archdata.iommu = NULL;

	arm_smmu_domain_remove_master(smmu_domain, cfg);
@@ -1533,7 +1548,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) 


	/* Detach the dev from its current domain */

	if (dev->archdata.iommu)

		arm_smmu_detach_dev(dev, cfg);

		arm_smmu_detach_dev(dev->archdata.iommu, dev);



	ret = arm_smmu_domain_add_master(smmu_domain, cfg);

	if (!ret)
@@ -1939,6 +1954,7 @@ static struct iommu_ops arm_smmu_ops = { 
	.domain_alloc		= arm_smmu_domain_alloc,

	.domain_free		= arm_smmu_domain_free,

	.attach_dev		= arm_smmu_attach_dev,

	.detach_dev		= arm_smmu_detach_dev,

	.map			= arm_smmu_map,

	.unmap			= arm_smmu_unmap,

	.map_sg			= default_iommu_map_sg,