[PATCH 2/2] iommu/riscv: Add support for platform msi

Andrew Jones
2024-11-06T17:52:40Z

Apply platform_device_msi_init_and_alloc_irqs() to add support for
MSIs when the IOMMU is a platform device.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
drivers/iommu/riscv/iommu-platform.c | 102 ++++++++++++++++++++++-----
1 file changed, 84 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/riscv/iommu-platform.c b/drivers/iommu/riscv/iommu-platform.c
index da336863f152..89aa622bcbde 100644
--- a/drivers/iommu/riscv/iommu-platform.c
+++ b/drivers/iommu/riscv/iommu-platform.c
@@ -11,18 +11,41 @@
*/

#include <linux/kernel.h>
+#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
+#include <linux/msi.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))
+ pr_warn_once("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)
@@ -40,16 +63,6 @@ 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,
@@ -57,13 +70,60 @@ static int riscv_iommu_platform_probe(struct platform_device *pdev)
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");
+ 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");
+ 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) {
+ dev_warn(dev, "\n");
+ return dev_err_probe(dev, -ENODEV,
+ "unable to use wire-signaled interrupts\n");
+ }
+
+ dev_warn(dev, " - falling back to wired irqs\n");
+ fallthrough;

- /* 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);
+ 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);
@@ -71,7 +131,13 @@ static int riscv_iommu_platform_probe(struct platform_device *pdev)

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 const struct of_device_id riscv_iommu_of_match[] = {
--
2.47.0