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247 lines
6.2 KiB
247 lines
6.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* OF helpers for IOMMU |
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* |
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* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. |
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*/ |
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#include <linux/export.h> |
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#include <linux/iommu.h> |
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#include <linux/limits.h> |
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#include <linux/module.h> |
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#include <linux/msi.h> |
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#include <linux/of.h> |
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#include <linux/of_iommu.h> |
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#include <linux/of_pci.h> |
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#include <linux/pci.h> |
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#include <linux/slab.h> |
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#include <linux/fsl/mc.h> |
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#define NO_IOMMU 1 |
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/** |
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* of_get_dma_window - Parse *dma-window property and returns 0 if found. |
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* |
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* @dn: device node |
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* @prefix: prefix for property name if any |
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* @index: index to start to parse |
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* @busno: Returns busno if supported. Otherwise pass NULL |
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* @addr: Returns address that DMA starts |
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* @size: Returns the range that DMA can handle |
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* |
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* This supports different formats flexibly. "prefix" can be |
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* configured if any. "busno" and "index" are optionally |
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* specified. Set 0(or NULL) if not used. |
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*/ |
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int of_get_dma_window(struct device_node *dn, const char *prefix, int index, |
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unsigned long *busno, dma_addr_t *addr, size_t *size) |
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{ |
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const __be32 *dma_window, *end; |
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int bytes, cur_index = 0; |
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char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX]; |
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if (!dn || !addr || !size) |
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return -EINVAL; |
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if (!prefix) |
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prefix = ""; |
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snprintf(propname, sizeof(propname), "%sdma-window", prefix); |
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snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix); |
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snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix); |
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dma_window = of_get_property(dn, propname, &bytes); |
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if (!dma_window) |
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return -ENODEV; |
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end = dma_window + bytes / sizeof(*dma_window); |
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while (dma_window < end) { |
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u32 cells; |
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const void *prop; |
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/* busno is one cell if supported */ |
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if (busno) |
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*busno = be32_to_cpup(dma_window++); |
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prop = of_get_property(dn, addrname, NULL); |
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if (!prop) |
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prop = of_get_property(dn, "#address-cells", NULL); |
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cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn); |
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if (!cells) |
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return -EINVAL; |
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*addr = of_read_number(dma_window, cells); |
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dma_window += cells; |
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prop = of_get_property(dn, sizename, NULL); |
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cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn); |
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if (!cells) |
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return -EINVAL; |
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*size = of_read_number(dma_window, cells); |
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dma_window += cells; |
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if (cur_index++ == index) |
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break; |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(of_get_dma_window); |
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static int of_iommu_xlate(struct device *dev, |
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struct of_phandle_args *iommu_spec) |
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{ |
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const struct iommu_ops *ops; |
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struct fwnode_handle *fwnode = &iommu_spec->np->fwnode; |
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int ret; |
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ops = iommu_ops_from_fwnode(fwnode); |
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if ((ops && !ops->of_xlate) || |
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!of_device_is_available(iommu_spec->np)) |
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return NO_IOMMU; |
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ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops); |
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if (ret) |
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return ret; |
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/* |
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* The otherwise-empty fwspec handily serves to indicate the specific |
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* IOMMU device we're waiting for, which will be useful if we ever get |
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* a proper probe-ordering dependency mechanism in future. |
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*/ |
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if (!ops) |
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return driver_deferred_probe_check_state(dev); |
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if (!try_module_get(ops->owner)) |
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return -ENODEV; |
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ret = ops->of_xlate(dev, iommu_spec); |
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module_put(ops->owner); |
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return ret; |
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} |
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static int of_iommu_configure_dev_id(struct device_node *master_np, |
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struct device *dev, |
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const u32 *id) |
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{ |
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struct of_phandle_args iommu_spec = { .args_count = 1 }; |
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int err; |
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err = of_map_id(master_np, *id, "iommu-map", |
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"iommu-map-mask", &iommu_spec.np, |
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iommu_spec.args); |
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if (err) |
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return err == -ENODEV ? NO_IOMMU : err; |
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err = of_iommu_xlate(dev, &iommu_spec); |
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of_node_put(iommu_spec.np); |
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return err; |
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} |
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static int of_iommu_configure_dev(struct device_node *master_np, |
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struct device *dev) |
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{ |
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struct of_phandle_args iommu_spec; |
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int err = NO_IOMMU, idx = 0; |
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while (!of_parse_phandle_with_args(master_np, "iommus", |
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"#iommu-cells", |
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idx, &iommu_spec)) { |
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err = of_iommu_xlate(dev, &iommu_spec); |
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of_node_put(iommu_spec.np); |
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idx++; |
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if (err) |
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break; |
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} |
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return err; |
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} |
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struct of_pci_iommu_alias_info { |
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struct device *dev; |
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struct device_node *np; |
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}; |
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static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data) |
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{ |
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struct of_pci_iommu_alias_info *info = data; |
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u32 input_id = alias; |
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return of_iommu_configure_dev_id(info->np, info->dev, &input_id); |
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} |
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static int of_iommu_configure_device(struct device_node *master_np, |
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struct device *dev, const u32 *id) |
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{ |
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return (id) ? of_iommu_configure_dev_id(master_np, dev, id) : |
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of_iommu_configure_dev(master_np, dev); |
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} |
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const struct iommu_ops *of_iommu_configure(struct device *dev, |
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struct device_node *master_np, |
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const u32 *id) |
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{ |
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const struct iommu_ops *ops = NULL; |
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struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); |
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int err = NO_IOMMU; |
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if (!master_np) |
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return NULL; |
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if (fwspec) { |
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if (fwspec->ops) |
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return fwspec->ops; |
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/* In the deferred case, start again from scratch */ |
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iommu_fwspec_free(dev); |
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} |
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/* |
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* We don't currently walk up the tree looking for a parent IOMMU. |
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* See the `Notes:' section of |
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* Documentation/devicetree/bindings/iommu/iommu.txt |
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*/ |
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if (dev_is_pci(dev)) { |
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struct of_pci_iommu_alias_info info = { |
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.dev = dev, |
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.np = master_np, |
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}; |
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pci_request_acs(); |
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err = pci_for_each_dma_alias(to_pci_dev(dev), |
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of_pci_iommu_init, &info); |
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} else { |
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err = of_iommu_configure_device(master_np, dev, id); |
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fwspec = dev_iommu_fwspec_get(dev); |
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if (!err && fwspec) |
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of_property_read_u32(master_np, "pasid-num-bits", |
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&fwspec->num_pasid_bits); |
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} |
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/* |
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* Two success conditions can be represented by non-negative err here: |
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* >0 : there is no IOMMU, or one was unavailable for non-fatal reasons |
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* 0 : we found an IOMMU, and dev->fwspec is initialised appropriately |
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* <0 : any actual error |
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*/ |
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if (!err) { |
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/* The fwspec pointer changed, read it again */ |
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fwspec = dev_iommu_fwspec_get(dev); |
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ops = fwspec->ops; |
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} |
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/* |
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* If we have reason to believe the IOMMU driver missed the initial |
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* probe for dev, replay it to get things in order. |
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*/ |
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if (!err && dev->bus && !device_iommu_mapped(dev)) |
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err = iommu_probe_device(dev); |
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/* Ignore all other errors apart from EPROBE_DEFER */ |
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if (err == -EPROBE_DEFER) { |
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ops = ERR_PTR(err); |
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} else if (err < 0) { |
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dev_dbg(dev, "Adding to IOMMU failed: %d\n", err); |
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ops = NULL; |
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} |
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return ops; |
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}
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