/* * OF helpers for IOMMU * * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. */ #include #include #include #include #include #include #include static const struct of_device_id __iommu_of_table_sentinel __used __section(__iommu_of_table_end); /** * 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 bool of_iommu_driver_present(struct device_node *np) { /* * If the IOMMU still isn't ready by the time we reach init, assume * it never will be. We don't want to defer indefinitely, nor attempt * to dereference __iommu_of_table after it's been freed. */ if (system_state > SYSTEM_BOOTING) return false; return of_match_node(&__iommu_of_table, np); } static const struct iommu_ops *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) || (!ops && !of_iommu_driver_present(iommu_spec->np))) return NULL; err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops); if (err) return ERR_PTR(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 ERR_PTR(-EPROBE_DEFER); err = ops->of_xlate(dev, iommu_spec); if (err) return ERR_PTR(err); return ops; } static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data) { struct of_phandle_args *iommu_spec = data; iommu_spec->args[0] = alias; return iommu_spec->np == pdev->bus->dev.of_node; } static const struct iommu_ops *of_pci_iommu_init(struct pci_dev *pdev, struct device_node *bridge_np) { const struct iommu_ops *ops; struct of_phandle_args iommu_spec; int err; /* * Start by tracing the RID alias down the PCI topology as * far as the host bridge whose OF node we have... * (we're not even attempting to handle multi-alias devices yet) */ iommu_spec.args_count = 1; iommu_spec.np = bridge_np; pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec); /* * ...then find out what that becomes once it escapes the PCI * bus into the system beyond, and which IOMMU it ends up at. */ iommu_spec.np = NULL; err = of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map", "iommu-map-mask", &iommu_spec.np, iommu_spec.args); if (err) return err == -ENODEV ? NULL : ERR_PTR(err); ops = of_iommu_xlate(&pdev->dev, &iommu_spec); of_node_put(iommu_spec.np); return ops; } static const struct iommu_ops *of_platform_iommu_init(struct device *dev, struct device_node *np) { struct of_phandle_args iommu_spec; const struct iommu_ops *ops = NULL; int idx = 0; /* * We don't currently walk up the tree looking for a parent IOMMU. * See the `Notes:' section of * Documentation/devicetree/bindings/iommu/iommu.txt */ while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", idx, &iommu_spec)) { ops = of_iommu_xlate(dev, &iommu_spec); of_node_put(iommu_spec.np); idx++; if (IS_ERR_OR_NULL(ops)) break; } return ops; } const struct iommu_ops *of_iommu_configure(struct device *dev, struct device_node *master_np) { const struct iommu_ops *ops; struct iommu_fwspec *fwspec = dev->iommu_fwspec; 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); } if (dev_is_pci(dev)) ops = of_pci_iommu_init(to_pci_dev(dev), master_np); else ops = of_platform_iommu_init(dev, master_np); /* * If we have reason to believe the IOMMU driver missed the initial * add_device callback for dev, replay it to get things in order. */ if (!IS_ERR_OR_NULL(ops) && ops->add_device && dev->bus && !dev->iommu_group) { int err = ops->add_device(dev); if (err) ops = ERR_PTR(err); } return ops; } static int __init of_iommu_init(void) { struct device_node *np; const struct of_device_id *match, *matches = &__iommu_of_table; for_each_matching_node_and_match(np, matches, &match) { const of_iommu_init_fn init_fn = match->data; if (init_fn && init_fn(np)) pr_err("Failed to initialise IOMMU %s\n", of_node_full_name(np)); } return 0; } postcore_initcall_sync(of_iommu_init);