Quelle  iommu-platform.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * RISC-V IOMMU as a platform device
 *
 * Copyright © 2023 FORTH-ICS/CARV
 * Copyright © 2023-2024 Rivos Inc.
 *
 * Authors
 * Nick Kossifidis <mick@ics.forth.gr>
 * Tomasz Jeznach <tjeznach@rivosinc.com>
 */

#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, ret;

 iommu = devm_kzalloc(dev, sizeof(*iommu), GFP_KERNEL);
 if (!iommu)
  return -ENOMEM;

 iommu->dev = dev;
 iommu->reg = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 if (IS_ERR(iommu->reg))
  return dev_err_probe(dev, PTR_ERR(iommu->reg),
         "could not map register region\n");

 dev_set_drvdata(dev, iommu);

 /* Check device reported capabilities / features. */
 iommu->caps = riscv_iommu_readq(iommu, RISCV_IOMMU_REG_CAPABILITIES);
 iommu->fctl = riscv_iommu_readl(iommu, RISCV_IOMMU_REG_FCTL);

 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;

 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");
  }

  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)
{
 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[] = {
 {.compatible = "riscv,iommu",},
 {},
};

static struct platform_driver riscv_iommu_platform_driver = {
 .probe = riscv_iommu_platform_probe,
 .remove = riscv_iommu_platform_remove,
 .shutdown = riscv_iommu_platform_shutdown,
 .driver = {
  .name = "riscv,iommu",
  .of_match_table = riscv_iommu_of_match,
  .suppress_bind_attrs = true,
 },
};

builtin_platform_driver(riscv_iommu_platform_driver);