Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / drivers / iommu / of_iommu.c
blob5c36a8b7656ae2b4f298dfa9793807085e9e0708
1 /*
2 * OF helpers for IOMMU
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
13 * more details.
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>
23 #include <linux/of.h>
24 #include <linux/of_iommu.h>
25 #include <linux/of_pci.h>
26 #include <linux/slab.h>
28 #define NO_IOMMU 1
30 static const struct of_device_id __iommu_of_table_sentinel
31 __used __section(__iommu_of_table_end);
33 /**
34 * of_get_dma_window - Parse *dma-window property and returns 0 if found.
36 * @dn: device node
37 * @prefix: prefix for property name if any
38 * @index: index to start to parse
39 * @busno: Returns busno if supported. Otherwise pass NULL
40 * @addr: Returns address that DMA starts
41 * @size: Returns the range that DMA can handle
43 * This supports different formats flexibly. "prefix" can be
44 * configured if any. "busno" and "index" are optionally
45 * specified. Set 0(or NULL) if not used.
47 int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
48 unsigned long *busno, dma_addr_t *addr, size_t *size)
50 const __be32 *dma_window, *end;
51 int bytes, cur_index = 0;
52 char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];
54 if (!dn || !addr || !size)
55 return -EINVAL;
57 if (!prefix)
58 prefix = "";
60 snprintf(propname, sizeof(propname), "%sdma-window", prefix);
61 snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);
62 snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);
64 dma_window = of_get_property(dn, propname, &bytes);
65 if (!dma_window)
66 return -ENODEV;
67 end = dma_window + bytes / sizeof(*dma_window);
69 while (dma_window < end) {
70 u32 cells;
71 const void *prop;
73 /* busno is one cell if supported */
74 if (busno)
75 *busno = be32_to_cpup(dma_window++);
77 prop = of_get_property(dn, addrname, NULL);
78 if (!prop)
79 prop = of_get_property(dn, "#address-cells", NULL);
81 cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
82 if (!cells)
83 return -EINVAL;
84 *addr = of_read_number(dma_window, cells);
85 dma_window += cells;
87 prop = of_get_property(dn, sizename, NULL);
88 cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
89 if (!cells)
90 return -EINVAL;
91 *size = of_read_number(dma_window, cells);
92 dma_window += cells;
94 if (cur_index++ == index)
95 break;
97 return 0;
99 EXPORT_SYMBOL_GPL(of_get_dma_window);
101 static bool of_iommu_driver_present(struct device_node *np)
104 * If the IOMMU still isn't ready by the time we reach init, assume
105 * it never will be. We don't want to defer indefinitely, nor attempt
106 * to dereference __iommu_of_table after it's been freed.
108 if (system_state >= SYSTEM_RUNNING)
109 return false;
111 return of_match_node(&__iommu_of_table, np);
114 static int of_iommu_xlate(struct device *dev,
115 struct of_phandle_args *iommu_spec)
117 const struct iommu_ops *ops;
118 struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
119 int err;
121 ops = iommu_ops_from_fwnode(fwnode);
122 if ((ops && !ops->of_xlate) ||
123 !of_device_is_available(iommu_spec->np) ||
124 (!ops && !of_iommu_driver_present(iommu_spec->np)))
125 return NO_IOMMU;
127 err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
128 if (err)
129 return err;
131 * The otherwise-empty fwspec handily serves to indicate the specific
132 * IOMMU device we're waiting for, which will be useful if we ever get
133 * a proper probe-ordering dependency mechanism in future.
135 if (!ops)
136 return -EPROBE_DEFER;
138 return ops->of_xlate(dev, iommu_spec);
141 struct of_pci_iommu_alias_info {
142 struct device *dev;
143 struct device_node *np;
146 static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
148 struct of_pci_iommu_alias_info *info = data;
149 struct of_phandle_args iommu_spec = { .args_count = 1 };
150 int err;
152 err = of_pci_map_rid(info->np, alias, "iommu-map",
153 "iommu-map-mask", &iommu_spec.np,
154 iommu_spec.args);
155 if (err)
156 return err == -ENODEV ? NO_IOMMU : err;
158 err = of_iommu_xlate(info->dev, &iommu_spec);
159 of_node_put(iommu_spec.np);
160 return err;
163 const struct iommu_ops *of_iommu_configure(struct device *dev,
164 struct device_node *master_np)
166 const struct iommu_ops *ops = NULL;
167 struct iommu_fwspec *fwspec = dev->iommu_fwspec;
168 int err = NO_IOMMU;
170 if (!master_np)
171 return NULL;
173 if (fwspec) {
174 if (fwspec->ops)
175 return fwspec->ops;
177 /* In the deferred case, start again from scratch */
178 iommu_fwspec_free(dev);
182 * We don't currently walk up the tree looking for a parent IOMMU.
183 * See the `Notes:' section of
184 * Documentation/devicetree/bindings/iommu/iommu.txt
186 if (dev_is_pci(dev)) {
187 struct of_pci_iommu_alias_info info = {
188 .dev = dev,
189 .np = master_np,
192 err = pci_for_each_dma_alias(to_pci_dev(dev),
193 of_pci_iommu_init, &info);
194 } else {
195 struct of_phandle_args iommu_spec;
196 int idx = 0;
198 while (!of_parse_phandle_with_args(master_np, "iommus",
199 "#iommu-cells",
200 idx, &iommu_spec)) {
201 err = of_iommu_xlate(dev, &iommu_spec);
202 of_node_put(iommu_spec.np);
203 idx++;
204 if (err)
205 break;
210 * Two success conditions can be represented by non-negative err here:
211 * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
212 * 0 : we found an IOMMU, and dev->fwspec is initialised appropriately
213 * <0 : any actual error
215 if (!err)
216 ops = dev->iommu_fwspec->ops;
218 * If we have reason to believe the IOMMU driver missed the initial
219 * add_device callback for dev, replay it to get things in order.
221 if (ops && ops->add_device && dev->bus && !dev->iommu_group)
222 err = ops->add_device(dev);
224 /* Ignore all other errors apart from EPROBE_DEFER */
225 if (err == -EPROBE_DEFER) {
226 ops = ERR_PTR(err);
227 } else if (err < 0) {
228 dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
229 ops = NULL;
232 return ops;