summaryrefslogtreecommitdiff
path: root/drivers/iommu/of_iommu.c
blob: c13eecac0e8a63f2569a862e09146c7be9b0b6b5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/*
 * OF helpers for IOMMU
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <linux/export.h>
#include <linux/iommu.h>
#include <linux/limits.h>
#include <linux/of.h>
#include <linux/of_iommu.h>
#include <linux/of_pci.h>
#include <linux/slab.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 err;

	ops = iommu_ops_from_fwnode(fwnode);
	if ((ops && !ops->of_xlate) ||
	    !of_device_is_available(iommu_spec->np))
		return NO_IOMMU;

	err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
	if (err)
		return err;
	/*
	 * 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);

	return ops->of_xlate(dev, iommu_spec);
}

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;
	struct of_phandle_args iommu_spec = { .args_count = 1 };
	int err;

	err = of_map_rid(info->np, alias, "iommu-map", "iommu-map-mask",
			 &iommu_spec.np, iommu_spec.args);
	if (err)
		return err == -ENODEV ? NO_IOMMU : err;

	err = of_iommu_xlate(info->dev, &iommu_spec);
	of_node_put(iommu_spec.np);
	return err;
}

const struct iommu_ops *of_iommu_configure(struct device *dev,
					   struct device_node *master_np)
{
	const struct iommu_ops *ops = NULL;
	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
	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,
		};

		err = pci_for_each_dma_alias(to_pci_dev(dev),
					     of_pci_iommu_init, &info);
	} else {
		struct of_phandle_args iommu_spec;
		int 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;
		}
	}

	/*
	 * 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)
		ops = dev->iommu_fwspec->ops;
	/*
	 * If we have reason to believe the IOMMU driver missed the initial
	 * add_device callback for dev, replay it to get things in order.
	 */
	if (ops && ops->add_device && dev->bus && !dev->iommu_group)
		err = ops->add_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;
}