// SPDX-License-Identifier: GPL-2.0-only /* * OF helpers for IOMMU * * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. */ #include <linux/export.h> #include <linux/iommu.h> #include <linux/limits.h> #include <linux/pci.h> #include <linux/msi.h> #include <linux/of.h> #include <linux/of_iommu.h> #include <linux/of_pci.h> #include <linux/slab.h> #include <linux/fsl/mc.h> #define NO_IOMMU 1 /** * of_get_dma_window - Parse *dma-window property and returns 0 if found. * * @dn: device node * @prefix: prefix for property name if any * @index: index to start to parse * @busno: Returns busno if supported. Otherwise pass NULL * @addr: Returns address that DMA starts * @size: Returns the range that DMA can handle * * This supports different formats flexibly. "prefix" can be * configured if any. "busno" and "index" are optionally * specified. Set 0(or NULL) if not used. */ int of_get_dma_window(struct device_node *dn, const char *prefix, int index, unsigned long *busno, dma_addr_t *addr, size_t *size) { const __be32 *dma_window, *end; int bytes, cur_index = 0; char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX]; if (!dn || !addr || !size) return -EINVAL; if (!prefix) prefix = ""; snprintf(propname, sizeof(propname), "%sdma-window", prefix); snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix); snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix); dma_window = of_get_property(dn, propname, &bytes); if (!dma_window) return -ENODEV; end = dma_window + bytes / sizeof(*dma_window); while (dma_window < end) { u32 cells; const void *prop; /* busno is one cell if supported */ if (busno) *busno = be32_to_cpup(dma_window++); prop = of_get_property(dn, addrname, NULL); if (!prop) prop = of_get_property(dn, "#address-cells", NULL); cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn); if (!cells) return -EINVAL; *addr = of_read_number(dma_window, cells); dma_window += cells; prop = of_get_property(dn, sizename, NULL); cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn); if (!cells) return -EINVAL; *size = of_read_number(dma_window, cells); dma_window += cells; if (cur_index++ == index) break; } return 0; } EXPORT_SYMBOL_GPL(of_get_dma_window); static int of_iommu_xlate(struct device *dev, struct of_phandle_args *iommu_spec) { const struct iommu_ops *ops; struct fwnode_handle *fwnode = &iommu_spec->np->fwnode; int err; ops = iommu_ops_from_fwnode(fwnode); if ((ops && !ops->of_xlate) || !of_device_is_available(iommu_spec->np)) return NO_IOMMU; err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops); if (err) return err; /* * The otherwise-empty fwspec handily serves to indicate the specific * IOMMU device we're waiting for, which will be useful if we ever get * a proper probe-ordering dependency mechanism in future. */ if (!ops) return driver_deferred_probe_check_state(dev); return ops->of_xlate(dev, iommu_spec); } struct of_pci_iommu_alias_info { struct device *dev; struct device_node *np; }; static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data) { struct of_pci_iommu_alias_info *info = data; struct of_phandle_args iommu_spec = { .args_count = 1 }; int err; err = of_map_rid(info->np, alias, "iommu-map", "iommu-map-mask", &iommu_spec.np, iommu_spec.args); if (err) return err == -ENODEV ? NO_IOMMU : err; err = of_iommu_xlate(info->dev, &iommu_spec); of_node_put(iommu_spec.np); return err; } static int of_fsl_mc_iommu_init(struct fsl_mc_device *mc_dev, struct device_node *master_np) { struct of_phandle_args iommu_spec = { .args_count = 1 }; int err; err = of_map_rid(master_np, mc_dev->icid, "iommu-map", "iommu-map-mask", &iommu_spec.np, iommu_spec.args); if (err) return err == -ENODEV ? NO_IOMMU : err; err = of_iommu_xlate(&mc_dev->dev, &iommu_spec); of_node_put(iommu_spec.np); return err; } const struct iommu_ops *of_iommu_configure(struct device *dev, struct device_node *master_np) { const struct iommu_ops *ops = NULL; struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); int err = NO_IOMMU; if (!master_np) return NULL; if (fwspec) { if (fwspec->ops) return fwspec->ops; /* In the deferred case, start again from scratch */ iommu_fwspec_free(dev); } /* * We don't currently walk up the tree looking for a parent IOMMU. * See the `Notes:' section of * Documentation/devicetree/bindings/iommu/iommu.txt */ if (dev_is_pci(dev)) { struct of_pci_iommu_alias_info info = { .dev = dev, .np = master_np, }; err = pci_for_each_dma_alias(to_pci_dev(dev), of_pci_iommu_init, &info); } else if (dev_is_fsl_mc(dev)) { err = of_fsl_mc_iommu_init(to_fsl_mc_device(dev), master_np); } else { struct of_phandle_args iommu_spec; int idx = 0; while (!of_parse_phandle_with_args(master_np, "iommus", "#iommu-cells", idx, &iommu_spec)) { err = of_iommu_xlate(dev, &iommu_spec); of_node_put(iommu_spec.np); idx++; if (err) break; } } /* * Two success conditions can be represented by non-negative err here: * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons * 0 : we found an IOMMU, and dev->fwspec is initialised appropriately * <0 : any actual error */ if (!err) { /* The fwspec pointer changed, read it again */ fwspec = dev_iommu_fwspec_get(dev); ops = fwspec->ops; } /* * If we have reason to believe the IOMMU driver missed the initial * probe for dev, replay it to get things in order. */ if (!err && dev->bus && !device_iommu_mapped(dev)) err = iommu_probe_device(dev); /* Ignore all other errors apart from EPROBE_DEFER */ if (err == -EPROBE_DEFER) { ops = ERR_PTR(err); } else if (err < 0) { dev_dbg(dev, "Adding to IOMMU failed: %d\n", err); ops = NULL; } return ops; }