Commit 166bdbd2 authored by Marc Zyngier's avatar Marc Zyngier Committed by Will Deacon
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iommu/arm-smmu: Add support for MSI on SMMUv3 



Despite being a platform device, the SMMUv3 is capable of signaling
interrupts using MSIs. Hook it into the platform MSI framework and
enjoy faults being reported in a new and exciting way.

Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
[will: tidied up the binding example and reworked most of the code]
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent c88ae5de

Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt

+19 −0
Original line number Diff line number Diff line
@@ -36,5 +36,24 @@ the PCIe specification. 
                      NOTE: this only applies to the SMMU itself, not

                      masters connected upstream of the SMMU.



- msi-parent        : See the generic MSI binding described in

                        devicetree/bindings/interrupt-controller/msi.txt

                      for a description of the msi-parent property.



- hisilicon,broken-prefetch-cmd

                    : Avoid sending CMD_PREFETCH_* commands to the SMMU.



** Example



        smmu@2b400000 {

                compatible = "arm,smmu-v3";

                reg = <0x0 0x2b400000 0x0 0x20000>;

                interrupts = <GIC_SPI 74 IRQ_TYPE_EDGE_RISING>,

                             <GIC_SPI 75 IRQ_TYPE_EDGE_RISING>,

                             <GIC_SPI 77 IRQ_TYPE_EDGE_RISING>,

                             <GIC_SPI 79 IRQ_TYPE_EDGE_RISING>;

                interrupt-names = "eventq", "priq", "cmdq-sync", "gerror";

                dma-coherent;

                #iommu-cells = <0>;

                msi-parent = <&its 0xff0000>;

        };

drivers/iommu/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -362,6 +362,7 @@ config ARM_SMMU_V3 
	depends on ARM64 && PCI

	select IOMMU_API

	select IOMMU_IO_PGTABLE_LPAE

	select GENERIC_MSI_IRQ_DOMAIN

	help

	  Support for implementations of the ARM System MMU architecture

	  version 3 providing translation support to a PCIe root complex.

drivers/iommu/arm-smmu-v3.c

+97 −8
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/iommu.h>

#include <linux/iopoll.h>

#include <linux/module.h>

#include <linux/msi.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/of_platform.h>
@@ -402,6 +403,31 @@ enum pri_resp { 
	PRI_RESP_SUCC,

};



enum arm_smmu_msi_index {

	EVTQ_MSI_INDEX,

	GERROR_MSI_INDEX,

	PRIQ_MSI_INDEX,

	ARM_SMMU_MAX_MSIS,

};



static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {

	[EVTQ_MSI_INDEX] = {

		ARM_SMMU_EVTQ_IRQ_CFG0,

		ARM_SMMU_EVTQ_IRQ_CFG1,

		ARM_SMMU_EVTQ_IRQ_CFG2,

	},

	[GERROR_MSI_INDEX] = {

		ARM_SMMU_GERROR_IRQ_CFG0,

		ARM_SMMU_GERROR_IRQ_CFG1,

		ARM_SMMU_GERROR_IRQ_CFG2,

	},

	[PRIQ_MSI_INDEX] = {

		ARM_SMMU_PRIQ_IRQ_CFG0,

		ARM_SMMU_PRIQ_IRQ_CFG1,

		ARM_SMMU_PRIQ_IRQ_CFG2,

	},

};



struct arm_smmu_cmdq_ent {

	/* Common fields */

	u8				opcode;
@@ -2176,6 +2202,72 @@ static int arm_smmu_write_reg_sync(struct arm_smmu_device *smmu, u32 val, 
					  1, ARM_SMMU_POLL_TIMEOUT_US);

}



static void arm_smmu_free_msis(void *data)

{

	struct device *dev = data;

	platform_msi_domain_free_irqs(dev);

}



static void arm_smmu_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg)

{

	phys_addr_t doorbell;

	struct device *dev = msi_desc_to_dev(desc);

	struct arm_smmu_device *smmu = dev_get_drvdata(dev);

	phys_addr_t *cfg = arm_smmu_msi_cfg[desc->platform.msi_index];



	doorbell = (((u64)msg->address_hi) << 32) | msg->address_lo;

	doorbell &= MSI_CFG0_ADDR_MASK << MSI_CFG0_ADDR_SHIFT;



	writeq_relaxed(doorbell, smmu->base + cfg[0]);

	writel_relaxed(msg->data, smmu->base + cfg[1]);

	writel_relaxed(MSI_CFG2_MEMATTR_DEVICE_nGnRE, smmu->base + cfg[2]);

}



static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)

{

	struct msi_desc *desc;

	int ret, nvec = ARM_SMMU_MAX_MSIS;

	struct device *dev = smmu->dev;



	/* Clear the MSI address regs */

	writeq_relaxed(0, smmu->base + ARM_SMMU_GERROR_IRQ_CFG0);

	writeq_relaxed(0, smmu->base + ARM_SMMU_EVTQ_IRQ_CFG0);



	if (smmu->features & ARM_SMMU_FEAT_PRI)

		writeq_relaxed(0, smmu->base + ARM_SMMU_PRIQ_IRQ_CFG0);

	else

		nvec--;



	if (!(smmu->features & ARM_SMMU_FEAT_MSI))

		return;



	/* Allocate MSIs for evtq, gerror and priq. Ignore cmdq */

	ret = platform_msi_domain_alloc_irqs(dev, nvec, arm_smmu_write_msi_msg);

	if (ret) {

		dev_warn(dev, "failed to allocate MSIs\n");

		return;

	}



	for_each_msi_entry(desc, dev) {

		switch (desc->platform.msi_index) {

		case EVTQ_MSI_INDEX:

			smmu->evtq.q.irq = desc->irq;

			break;

		case GERROR_MSI_INDEX:

			smmu->gerr_irq = desc->irq;

			break;

		case PRIQ_MSI_INDEX:

			smmu->priq.q.irq = desc->irq;

			break;

		default:	/* Unknown */

			continue;

		}

	}



	/* Add callback to free MSIs on teardown */

	devm_add_action(dev, arm_smmu_free_msis, dev);

}



static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)

{

	int ret, irq;
@@ -2189,11 +2281,9 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu) 
		return ret;

	}



	/* Clear the MSI address regs */

	writeq_relaxed(0, smmu->base + ARM_SMMU_GERROR_IRQ_CFG0);

	writeq_relaxed(0, smmu->base + ARM_SMMU_EVTQ_IRQ_CFG0);

	arm_smmu_setup_msis(smmu);



	/* Request wired interrupt lines */

	/* Request interrupt lines */

	irq = smmu->evtq.q.irq;

	if (irq) {

		ret = devm_request_threaded_irq(smmu->dev, irq,
@@ -2222,8 +2312,6 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu) 
	}



	if (smmu->features & ARM_SMMU_FEAT_PRI) {

		writeq_relaxed(0, smmu->base + ARM_SMMU_PRIQ_IRQ_CFG0);



		irq = smmu->priq.q.irq;

		if (irq) {

			ret = devm_request_threaded_irq(smmu->dev, irq,
@@ -2597,13 +2685,14 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev) 
	if (ret)

		return ret;



	/* Record our private device structure */

	platform_set_drvdata(pdev, smmu);



	/* Reset the device */

	ret = arm_smmu_device_reset(smmu);

	if (ret)

		goto out_free_structures;



	/* Record our private device structure */

	platform_set_drvdata(pdev, smmu);

	return 0;



out_free_structures:

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