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Commit ef6c1dc3 authored by Patrick Daly's avatar Patrick Daly
Browse files

iommu/arm-smmu: support mapping before enabling S1 translations 



For performance reasons there are clients who would like to move
from stage 1 bypass to stage 1 enabled without having to stop their
device.

Currently clients need to stop their device because they have to
create the required stage 1 mappings before re-enabling the device.
Add the new DOMAIN_ATTR_EARLY_MAP domain attribute to allow clients
to create stage 1 mappings after attaching but before enabling
stage 1 translations.

If the clients set the DOMAIN_ATTR_EARLY_MAP domain attribute to 1
before attaching then then once they attach the SMMU driver won't
enable stage 1 translations. This gives the client the opportunity to
create the required early mappings (for example using iommu_map).
When the client has finished creating the necessary early mappings
the client can then set the DOMAIN_ATTR_EARLY_MAP domain attribute
to 0, this will in turn enable stage 1 translations.

Change-Id: I9e95c5d2130f1d371e201eac69dec140cc773b1f
Signed-off-by: default avatarLiam Mark <lmark@codeaurora.org>
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent ef8bd289

drivers/iommu/arm-smmu.c

+50 −2
Original line number Diff line number Diff line
@@ -548,6 +548,8 @@ static void arm_smmu_unassign_table(struct arm_smmu_domain *smmu_domain); 
static int arm_smmu_arch_init(struct arm_smmu_device *smmu);

static void arm_smmu_arch_device_reset(struct arm_smmu_device *smmu);



static int arm_smmu_enable_s1_translations(struct arm_smmu_domain *smmu_domain);



static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)

{

	return container_of(dom, struct arm_smmu_domain, domain);
@@ -1424,7 +1426,9 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain, 


	/* SCTLR */

	reg = SCTLR_CFCFG | SCTLR_CFIE | SCTLR_CFRE | SCTLR_AFE | SCTLR_TRE;

	if (!(smmu_domain->attributes & (1 << DOMAIN_ATTR_S1_BYPASS)) ||



	if ((!(smmu_domain->attributes & (1 << DOMAIN_ATTR_S1_BYPASS)) &&

	     !(smmu_domain->attributes & (1 << DOMAIN_ATTR_EARLY_MAP))) ||

								!stage1)

		reg |= SCTLR_M;

	if (stage1)
@@ -2578,6 +2582,11 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain, 
				   (1 << DOMAIN_ATTR_USE_UPSTREAM_HINT));

		ret = 0;

		break;

	case DOMAIN_ATTR_EARLY_MAP:

		*((int *)data) = !!(smmu_domain->attributes

				    & (1 << DOMAIN_ATTR_EARLY_MAP));

		ret = 0;

		break;

	default:

		return -ENODEV;

	}
@@ -2716,6 +2725,24 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain, 
				1 << DOMAIN_ATTR_USE_UPSTREAM_HINT;

		ret = 0;

		break;

	case DOMAIN_ATTR_EARLY_MAP: {

		int early_map = *((int *)data);



		ret = 0;

		if (early_map) {

			smmu_domain->attributes |=

						1 << DOMAIN_ATTR_EARLY_MAP;

		} else {

			if (smmu_domain->smmu)

				ret = arm_smmu_enable_s1_translations(

								smmu_domain);



			if (!ret)

				smmu_domain->attributes &=

					~(1 << DOMAIN_ATTR_EARLY_MAP);

		}

		break;

	}

	default:

		ret = -ENODEV;

	}
@@ -2738,6 +2765,27 @@ static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args) 
	return iommu_fwspec_add_ids(dev, &fwid, 1);

}



static int arm_smmu_enable_s1_translations(struct arm_smmu_domain *smmu_domain)

{

	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;

	struct arm_smmu_device *smmu = smmu_domain->smmu;

	void __iomem *cb_base;

	u32 reg;

	int ret;



	cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);

	ret = arm_smmu_power_on(smmu->pwr);

	if (ret)

		return ret;



	reg = readl_relaxed(cb_base + ARM_SMMU_CB_SCTLR);

	reg |= SCTLR_M;



	writel_relaxed(reg, cb_base + ARM_SMMU_CB_SCTLR);

	arm_smmu_power_off(smmu->pwr);

	return ret;

}



static void arm_smmu_trigger_fault(struct iommu_domain *domain,

					unsigned long flags)

{

drivers/iommu/iommu-debug.c

+2 −0
Original line number Diff line number Diff line
@@ -69,6 +69,8 @@ static const char *iommu_debug_attr_to_string(enum iommu_attr attr) 
		return "DOMAIN_ATTR_S1_BYPASS";

	case DOMAIN_ATTR_FAST:

		return "DOMAIN_ATTR_FAST";

	case DOMAIN_ATTR_EARLY_MAP:

		return "DOMAIN_ATTR_EARLY_MAP";

	default:

		return "Unknown attr!";

	}

include/linux/iommu.h

+1 −0
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ enum iommu_attr { 
	DOMAIN_ATTR_FAST,

	DOMAIN_ATTR_PGTBL_INFO,

	DOMAIN_ATTR_USE_UPSTREAM_HINT,

	DOMAIN_ATTR_EARLY_MAP,

	DOMAIN_ATTR_MAX,

};