sync: rvck #114: Backport Linux RISC-V IOMMU Support

drivers/iommu/riscv/iommu-pci.c

@@ -101,6 +101,13 @@ static void riscv_iommu_pci_remove(struct pci_dev *pdev)
 	riscv_iommu_remove(iommu);
 }
 
+static void riscv_iommu_pci_shutdown(struct pci_dev *pdev)
+{
+	struct riscv_iommu_device *iommu = dev_get_drvdata(&pdev->dev);
+
+	riscv_iommu_disable(iommu);
+}
+
 static const struct pci_device_id riscv_iommu_pci_tbl[] = {
 	{PCI_VDEVICE(REDHAT, PCI_DEVICE_ID_REDHAT_RISCV_IOMMU), 0},
 	{PCI_VDEVICE(RIVOS, PCI_DEVICE_ID_RIVOS_RISCV_IOMMU_GA), 0},
@@ -112,6 +119,7 @@ static struct pci_driver riscv_iommu_pci_driver = {
 	.id_table = riscv_iommu_pci_tbl,
 	.probe = riscv_iommu_pci_probe,
 	.remove = riscv_iommu_pci_remove,
+	.shutdown = riscv_iommu_pci_shutdown,
 	.driver = {
 		.suppress_bind_attrs = true,
 	},

drivers/iommu/riscv/iommu-platform.c

@@ -11,18 +11,43 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 
 #include "iommu-bits.h"
 #include "iommu.h"
 
+static void riscv_iommu_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct device *dev = msi_desc_to_dev(desc);
+	struct riscv_iommu_device *iommu = dev_get_drvdata(dev);
+	u16 idx = desc->msi_index;
+	u64 addr;
+
+	addr = ((u64)msg->address_hi << 32) | msg->address_lo;
+
+	if (addr != (addr & RISCV_IOMMU_MSI_CFG_TBL_ADDR)) {
+		dev_err_once(dev,
+			     "uh oh, the IOMMU can't send MSIs to 0x%llx, sending to 0x%llx instead\n",
+			     addr, addr & RISCV_IOMMU_MSI_CFG_TBL_ADDR);
+	}
+
+	addr &= RISCV_IOMMU_MSI_CFG_TBL_ADDR;
+
+	riscv_iommu_writeq(iommu, RISCV_IOMMU_REG_MSI_CFG_TBL_ADDR(idx), addr);
+	riscv_iommu_writel(iommu, RISCV_IOMMU_REG_MSI_CFG_TBL_DATA(idx), msg->data);
+	riscv_iommu_writel(iommu, RISCV_IOMMU_REG_MSI_CFG_TBL_CTRL(idx), 0);
+}
+
 static int riscv_iommu_platform_probe(struct platform_device *pdev)
 {
+	enum riscv_iommu_igs_settings igs;
 	struct device *dev = &pdev->dev;
 	struct riscv_iommu_device *iommu = NULL;
 	struct resource *res = NULL;
-	int vec;
+	int vec, ret;
 
 	iommu = devm_kzalloc(dev, sizeof(*iommu), GFP_KERNEL);
 	if (!iommu)
@@ -40,38 +65,84 @@ static int riscv_iommu_platform_probe(struct platform_device *pdev)
 	iommu->caps = riscv_iommu_readq(iommu, RISCV_IOMMU_REG_CAPABILITIES);
 	iommu->fctl = riscv_iommu_readl(iommu, RISCV_IOMMU_REG_FCTL);
 
-	/* For now we only support WSI */
-	switch (FIELD_GET(RISCV_IOMMU_CAPABILITIES_IGS, iommu->caps)) {
-	case RISCV_IOMMU_CAPABILITIES_IGS_WSI:
-	case RISCV_IOMMU_CAPABILITIES_IGS_BOTH:
-		break;
-	default:
-		return dev_err_probe(dev, -ENODEV,
-				     "unable to use wire-signaled interrupts\n");
-	}
-
 	iommu->irqs_count = platform_irq_count(pdev);
 	if (iommu->irqs_count <= 0)
 		return dev_err_probe(dev, -ENODEV,
 				     "no IRQ resources provided\n");
 	if (iommu->irqs_count > RISCV_IOMMU_INTR_COUNT)
 		iommu->irqs_count = RISCV_IOMMU_INTR_COUNT;
 
-	for (vec = 0; vec < iommu->irqs_count; vec++)
-		iommu->irqs[vec] = platform_get_irq(pdev, vec);
+	igs = FIELD_GET(RISCV_IOMMU_CAPABILITIES_IGS, iommu->caps);
+	switch (igs) {
+	case RISCV_IOMMU_CAPABILITIES_IGS_BOTH:
+	case RISCV_IOMMU_CAPABILITIES_IGS_MSI:
+		if (is_of_node(dev->fwnode))
+			of_msi_configure(dev, to_of_node(dev->fwnode));
+
+		if (!dev_get_msi_domain(dev)) {
+			dev_warn(dev, "failed to find an MSI domain\n");
+			goto msi_fail;
+		}
+
+		ret = platform_device_msi_init_and_alloc_irqs(dev, iommu->irqs_count,
+							      riscv_iommu_write_msi_msg);
+		if (ret) {
+			dev_warn(dev, "failed to allocate MSIs\n");
+			goto msi_fail;
+		}
+
+		for (vec = 0; vec < iommu->irqs_count; vec++)
+			iommu->irqs[vec] = msi_get_virq(dev, vec);
+
+		/* Enable message-signaled interrupts, fctl.WSI */
+		if (iommu->fctl & RISCV_IOMMU_FCTL_WSI) {
+			iommu->fctl ^= RISCV_IOMMU_FCTL_WSI;
+			riscv_iommu_writel(iommu, RISCV_IOMMU_REG_FCTL, iommu->fctl);
+		}
+
+		dev_info(dev, "using MSIs\n");
+		break;
+
+msi_fail:
+		if (igs != RISCV_IOMMU_CAPABILITIES_IGS_BOTH) {
+			return dev_err_probe(dev, -ENODEV,
+					     "unable to use wire-signaled interrupts\n");
+		}
 
-	/* Enable wire-signaled interrupts, fctl.WSI */
-	if (!(iommu->fctl & RISCV_IOMMU_FCTL_WSI)) {
-		iommu->fctl |= RISCV_IOMMU_FCTL_WSI;
-		riscv_iommu_writel(iommu, RISCV_IOMMU_REG_FCTL, iommu->fctl);
+		fallthrough;
+
+	case RISCV_IOMMU_CAPABILITIES_IGS_WSI:
+		for (vec = 0; vec < iommu->irqs_count; vec++)
+			iommu->irqs[vec] = platform_get_irq(pdev, vec);
+
+		/* Enable wire-signaled interrupts, fctl.WSI */
+		if (!(iommu->fctl & RISCV_IOMMU_FCTL_WSI)) {
+			iommu->fctl |= RISCV_IOMMU_FCTL_WSI;
+			riscv_iommu_writel(iommu, RISCV_IOMMU_REG_FCTL, iommu->fctl);
+		}
+		dev_info(dev, "using wire-signaled interrupts\n");
+		break;
+	default:
+		return dev_err_probe(dev, -ENODEV, "invalid IGS\n");
 	}
 
 	return riscv_iommu_init(iommu);
 };
 
 static void riscv_iommu_platform_remove(struct platform_device *pdev)
 {
-	riscv_iommu_remove(dev_get_drvdata(&pdev->dev));
+	struct riscv_iommu_device *iommu = dev_get_drvdata(&pdev->dev);
+	bool msi = !(iommu->fctl & RISCV_IOMMU_FCTL_WSI);
+
+	riscv_iommu_remove(iommu);
+
+	if (msi)
+		platform_device_msi_free_irqs_all(&pdev->dev);
+};
+
+static void riscv_iommu_platform_shutdown(struct platform_device *pdev)
+{
+	riscv_iommu_disable(dev_get_drvdata(&pdev->dev));
 };
 
 static const struct of_device_id riscv_iommu_of_match[] = {
@@ -82,6 +153,7 @@ static const struct of_device_id riscv_iommu_of_match[] = {
 static struct platform_driver riscv_iommu_platform_driver = {
 	.probe = riscv_iommu_platform_probe,
 	.remove_new = riscv_iommu_platform_remove,
+	.shutdown = riscv_iommu_platform_shutdown,
 	.driver = {
 		.name = "riscv,iommu",
 		.of_match_table = riscv_iommu_of_match,

drivers/iommu/riscv/iommu.c

@@ -240,6 +240,12 @@ static int riscv_iommu_queue_enable(struct riscv_iommu_device *iommu,
 		return rc;
 	}
 
+	/* Empty queue before enabling it */
+	if (queue->qid == RISCV_IOMMU_INTR_CQ)
+		riscv_iommu_writel(queue->iommu, Q_TAIL(queue), 0);
+	else
+		riscv_iommu_writel(queue->iommu, Q_HEAD(queue), 0);
+
 	/*
 	 * Enable queue with interrupts, clear any memory fault if any.
 	 * Wait for the hardware to acknowledge request and activate queue
@@ -645,9 +651,11 @@ static struct riscv_iommu_dc *riscv_iommu_get_dc(struct riscv_iommu_device *iomm
  * This is best effort IOMMU translation shutdown flow.
  * Disable IOMMU without waiting for hardware response.
  */
-static void riscv_iommu_disable(struct riscv_iommu_device *iommu)
+void riscv_iommu_disable(struct riscv_iommu_device *iommu)
 {
-	riscv_iommu_writeq(iommu, RISCV_IOMMU_REG_DDTP, 0);
+	riscv_iommu_writeq(iommu, RISCV_IOMMU_REG_DDTP,
+			   FIELD_PREP(RISCV_IOMMU_DDTP_IOMMU_MODE,
+				      RISCV_IOMMU_DDTP_IOMMU_MODE_BARE));
 	riscv_iommu_writel(iommu, RISCV_IOMMU_REG_CQCSR, 0);
 	riscv_iommu_writel(iommu, RISCV_IOMMU_REG_FQCSR, 0);
 	riscv_iommu_writel(iommu, RISCV_IOMMU_REG_PQCSR, 0);
@@ -1270,11 +1278,11 @@ static phys_addr_t riscv_iommu_iova_to_phys(struct iommu_domain *iommu_domain,
 					    dma_addr_t iova)
 {
 	struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
-	unsigned long pte_size;
+	size_t pte_size;
 	unsigned long *ptr;
 
 	ptr = riscv_iommu_pte_fetch(domain, iova, &pte_size);
-	if (_io_pte_none(*ptr) || !_io_pte_present(*ptr))
+	if (!ptr)
 		return 0;
 
 	return pfn_to_phys(__page_val_to_pfn(*ptr)) | (iova & (pte_size - 1));

drivers/iommu/riscv/iommu.h

@@ -64,6 +64,7 @@ struct riscv_iommu_device {
 
 int riscv_iommu_init(struct riscv_iommu_device *iommu);
 void riscv_iommu_remove(struct riscv_iommu_device *iommu);
+void riscv_iommu_disable(struct riscv_iommu_device *iommu);
 
 #define riscv_iommu_readl(iommu, addr) \
 	readl_relaxed((iommu)->reg + (addr))