drivers/iommu/riscv/iommu-platform.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * RISC-V IOMMU as a platform device
   4  *
   5  * Copyright © 2023 FORTH-ICS/CARV
   6  * Copyright © 2023-2024 Rivos Inc.
   7  *
   8  * Authors
   9  *      Nick Kossifidis <mick@ics.forth.gr>
  10  *      Tomasz Jeznach <tjeznach@rivosinc.com>
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/of_platform.h>
  15 #include <linux/platform_device.h>
  16
  17 #include "iommu-bits.h"
  18 #include "iommu.h"
  19
  20 static int riscv_iommu_platform_probe(struct platform_device *pdev)
  21 {
  22         struct device *dev = &pdev->dev;
  23         struct riscv_iommu_device *iommu = NULL;
  24         struct resource *res = NULL;
  25         int vec;
  26
  27         iommu = devm_kzalloc(dev, sizeof(*iommu), GFP_KERNEL);
  28         if (!iommu)
  29                 return -ENOMEM;
  30
  31         iommu->dev = dev;
  32         iommu->reg = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
  33         if (IS_ERR(iommu->reg))
  34                 return dev_err_probe(dev, PTR_ERR(iommu->reg),
  35                                      "could not map register region\n");
  36
  37         dev_set_drvdata(dev, iommu);
  38
  39         /* Check device reported capabilities / features. */
  40         iommu->caps = riscv_iommu_readq(iommu, RISCV_IOMMU_REG_CAPABILITIES);
  41         iommu->fctl = riscv_iommu_readl(iommu, RISCV_IOMMU_REG_FCTL);
  42
  43         /* For now we only support WSI */
  44         switch (FIELD_GET(RISCV_IOMMU_CAPABILITIES_IGS, iommu->caps)) {
  45         case RISCV_IOMMU_CAPABILITIES_IGS_WSI:
  46         case RISCV_IOMMU_CAPABILITIES_IGS_BOTH:
  47                 break;
  48         default:
  49                 return dev_err_probe(dev, -ENODEV,
  50                                      "unable to use wire-signaled interrupts\n");
  51         }
  52
  53         iommu->irqs_count = platform_irq_count(pdev);
  54         if (iommu->irqs_count <= 0)
  55                 return dev_err_probe(dev, -ENODEV,
  56                                      "no IRQ resources provided\n");
  57         if (iommu->irqs_count > RISCV_IOMMU_INTR_COUNT)
  58                 iommu->irqs_count = RISCV_IOMMU_INTR_COUNT;
  59
  60         for (vec = 0; vec < iommu->irqs_count; vec++)
  61                 iommu->irqs[vec] = platform_get_irq(pdev, vec);
  62
  63         /* Enable wire-signaled interrupts, fctl.WSI */
  64         if (!(iommu->fctl & RISCV_IOMMU_FCTL_WSI)) {
  65                 iommu->fctl |= RISCV_IOMMU_FCTL_WSI;
  66                 riscv_iommu_writel(iommu, RISCV_IOMMU_REG_FCTL, iommu->fctl);
  67         }
  68
  69         return riscv_iommu_init(iommu);
  70 };
  71
  72 static void riscv_iommu_platform_remove(struct platform_device *pdev)
  73 {
  74         riscv_iommu_remove(dev_get_drvdata(&pdev->dev));
  75 };
  76
  77 static const struct of_device_id riscv_iommu_of_match[] = {
  78         {.compatible = "riscv,iommu",},
  79         {},
  80 };
  81
  82 static struct platform_driver riscv_iommu_platform_driver = {
  83         .probe = riscv_iommu_platform_probe,
  84         .remove = riscv_iommu_platform_remove,
  85         .driver = {
  86                 .name = "riscv,iommu",
  87                 .of_match_table = riscv_iommu_of_match,
  88                 .suppress_bind_attrs = true,
  89         },
  90 };
  91
  92 builtin_platform_driver(riscv_iommu_platform_driver);