4 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20 #include <linux/export.h>
21 #include <linux/iommu.h>
22 #include <linux/limits.h>
24 #include <linux/of_iommu.h>
25 #include <linux/of_pci.h>
26 #include <linux/slab.h>
28 static const struct of_device_id __iommu_of_table_sentinel
29 __used __section(__iommu_of_table_end);
32 * of_get_dma_window - Parse *dma-window property and returns 0 if found.
35 * @prefix: prefix for property name if any
36 * @index: index to start to parse
37 * @busno: Returns busno if supported. Otherwise pass NULL
38 * @addr: Returns address that DMA starts
39 * @size: Returns the range that DMA can handle
41 * This supports different formats flexibly. "prefix" can be
42 * configured if any. "busno" and "index" are optionally
43 * specified. Set 0(or NULL) if not used.
45 int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
46 unsigned long *busno, dma_addr_t *addr, size_t *size)
48 const __be32 *dma_window, *end;
49 int bytes, cur_index = 0;
50 char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];
52 if (!dn || !addr || !size)
58 snprintf(propname, sizeof(propname), "%sdma-window", prefix);
59 snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);
60 snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);
62 dma_window = of_get_property(dn, propname, &bytes);
65 end = dma_window + bytes / sizeof(*dma_window);
67 while (dma_window < end) {
71 /* busno is one cell if supported */
73 *busno = be32_to_cpup(dma_window++);
75 prop = of_get_property(dn, addrname, NULL);
77 prop = of_get_property(dn, "#address-cells", NULL);
79 cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
82 *addr = of_read_number(dma_window, cells);
85 prop = of_get_property(dn, sizename, NULL);
86 cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
89 *size = of_read_number(dma_window, cells);
92 if (cur_index++ == index)
97 EXPORT_SYMBOL_GPL(of_get_dma_window);
99 static bool of_iommu_driver_present(struct device_node *np)
102 * If the IOMMU still isn't ready by the time we reach init, assume
103 * it never will be. We don't want to defer indefinitely, nor attempt
104 * to dereference __iommu_of_table after it's been freed.
106 if (system_state > SYSTEM_BOOTING)
109 return of_match_node(&__iommu_of_table, np);
112 static const struct iommu_ops
113 *of_iommu_xlate(struct device *dev, struct of_phandle_args *iommu_spec)
115 const struct iommu_ops *ops;
116 struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
119 ops = iommu_ops_from_fwnode(fwnode);
120 if ((ops && !ops->of_xlate) ||
121 !of_device_is_available(iommu_spec->np) ||
122 (!ops && !of_iommu_driver_present(iommu_spec->np)))
125 err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
129 * The otherwise-empty fwspec handily serves to indicate the specific
130 * IOMMU device we're waiting for, which will be useful if we ever get
131 * a proper probe-ordering dependency mechanism in future.
134 return ERR_PTR(-EPROBE_DEFER);
136 err = ops->of_xlate(dev, iommu_spec);
143 static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
145 struct of_phandle_args *iommu_spec = data;
147 iommu_spec->args[0] = alias;
148 return iommu_spec->np == pdev->bus->dev.of_node;
151 static const struct iommu_ops
152 *of_pci_iommu_init(struct pci_dev *pdev, struct device_node *bridge_np)
154 const struct iommu_ops *ops;
155 struct of_phandle_args iommu_spec;
159 * Start by tracing the RID alias down the PCI topology as
160 * far as the host bridge whose OF node we have...
161 * (we're not even attempting to handle multi-alias devices yet)
163 iommu_spec.args_count = 1;
164 iommu_spec.np = bridge_np;
165 pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
167 * ...then find out what that becomes once it escapes the PCI
168 * bus into the system beyond, and which IOMMU it ends up at.
170 iommu_spec.np = NULL;
171 err = of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
172 "iommu-map-mask", &iommu_spec.np,
175 return err == -ENODEV ? NULL : ERR_PTR(err);
177 ops = of_iommu_xlate(&pdev->dev, &iommu_spec);
179 of_node_put(iommu_spec.np);
183 static const struct iommu_ops
184 *of_platform_iommu_init(struct device *dev, struct device_node *np)
186 struct of_phandle_args iommu_spec;
187 const struct iommu_ops *ops = NULL;
191 * We don't currently walk up the tree looking for a parent IOMMU.
192 * See the `Notes:' section of
193 * Documentation/devicetree/bindings/iommu/iommu.txt
195 while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells",
197 ops = of_iommu_xlate(dev, &iommu_spec);
198 of_node_put(iommu_spec.np);
200 if (IS_ERR_OR_NULL(ops))
207 const struct iommu_ops *of_iommu_configure(struct device *dev,
208 struct device_node *master_np)
210 const struct iommu_ops *ops;
211 struct iommu_fwspec *fwspec = dev->iommu_fwspec;
220 /* In the deferred case, start again from scratch */
221 iommu_fwspec_free(dev);
225 ops = of_pci_iommu_init(to_pci_dev(dev), master_np);
227 ops = of_platform_iommu_init(dev, master_np);
229 * If we have reason to believe the IOMMU driver missed the initial
230 * add_device callback for dev, replay it to get things in order.
232 if (!IS_ERR_OR_NULL(ops) && ops->add_device &&
233 dev->bus && !dev->iommu_group) {
234 int err = ops->add_device(dev);
240 /* Ignore all other errors apart from EPROBE_DEFER */
241 if (IS_ERR(ops) && (PTR_ERR(ops) != -EPROBE_DEFER)) {
242 dev_dbg(dev, "Adding to IOMMU failed: %ld\n", PTR_ERR(ops));
249 static int __init of_iommu_init(void)
251 struct device_node *np;
252 const struct of_device_id *match, *matches = &__iommu_of_table;
254 for_each_matching_node_and_match(np, matches, &match) {
255 const of_iommu_init_fn init_fn = match->data;
257 if (init_fn && init_fn(np))
258 pr_err("Failed to initialise IOMMU %s\n",
259 of_node_full_name(np));
264 postcore_initcall_sync(of_iommu_init);