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- // 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/module.h>
- #include <linux/msi.h>
- #include <linux/of.h>
- #include <linux/of_iommu.h>
- #include <linux/of_pci.h>
- #include <linux/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 ret;
- ops = iommu_ops_from_fwnode(fwnode);
- if ((ops && !ops->of_xlate) ||
- !of_device_is_available(iommu_spec->np))
- return NO_IOMMU;
- ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
- if (ret)
- return ret;
- /*
- * 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);
- if (!try_module_get(ops->owner))
- return -ENODEV;
- ret = ops->of_xlate(dev, iommu_spec);
- module_put(ops->owner);
- return ret;
- }
- static int of_iommu_configure_dev_id(struct device_node *master_np,
- struct device *dev,
- const u32 *id)
- {
- struct of_phandle_args iommu_spec = { .args_count = 1 };
- int err;
- err = of_map_id(master_np, *id, "iommu-map",
- "iommu-map-mask", &iommu_spec.np,
- iommu_spec.args);
- if (err)
- return err == -ENODEV ? NO_IOMMU : err;
- err = of_iommu_xlate(dev, &iommu_spec);
- of_node_put(iommu_spec.np);
- return err;
- }
- static int of_iommu_configure_dev(struct device_node *master_np,
- struct device *dev)
- {
- struct of_phandle_args iommu_spec;
- int err = NO_IOMMU, 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;
- }
- return err;
- }
- 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;
- u32 input_id = alias;
- return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
- }
- static int of_iommu_configure_device(struct device_node *master_np,
- struct device *dev, const u32 *id)
- {
- return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
- of_iommu_configure_dev(master_np, dev);
- }
- const struct iommu_ops *of_iommu_configure(struct device *dev,
- struct device_node *master_np,
- const u32 *id)
- {
- 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,
- };
- pci_request_acs();
- err = pci_for_each_dma_alias(to_pci_dev(dev),
- of_pci_iommu_init, &info);
- } else {
- err = of_iommu_configure_device(master_np, dev, id);
- fwspec = dev_iommu_fwspec_get(dev);
- if (!err && fwspec)
- of_property_read_u32(master_np, "pasid-num-bits",
- &fwspec->num_pasid_bits);
- }
- /*
- * 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;
- }
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