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