1/*
  2 * OF helpers for IOMMU
  3 *
  4 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  5 *
  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.
  9 *
 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.
 14 *
 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.
 18 */
 19
 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>
 27
 28static const struct of_device_id __iommu_of_table_sentinel
 29	__used __section(__iommu_of_table_end);
 30
 31/**
 32 * of_get_dma_window - Parse *dma-window property and returns 0 if found.
 33 *
 34 * @dn: device node
 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
 40 *
 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.
 44 */
 45int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
 46		      unsigned long *busno, dma_addr_t *addr, size_t *size)
 47{
 48	const __be32 *dma_window, *end;
 49	int bytes, cur_index = 0;
 50	char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];
 51
 52	if (!dn || !addr || !size)
 53		return -EINVAL;
 54
 55	if (!prefix)
 56		prefix = "";
 57
 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);
 61
 62	dma_window = of_get_property(dn, propname, &bytes);
 63	if (!dma_window)
 64		return -ENODEV;
 65	end = dma_window + bytes / sizeof(*dma_window);
 66
 67	while (dma_window < end) {
 68		u32 cells;
 69		const void *prop;
 70
 71		/* busno is one cell if supported */
 72		if (busno)
 73			*busno = be32_to_cpup(dma_window++);
 74
 75		prop = of_get_property(dn, addrname, NULL);
 76		if (!prop)
 77			prop = of_get_property(dn, "#address-cells", NULL);
 78
 79		cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
 80		if (!cells)
 81			return -EINVAL;
 82		*addr = of_read_number(dma_window, cells);
 83		dma_window += cells;
 84
 85		prop = of_get_property(dn, sizename, NULL);
 86		cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
 87		if (!cells)
 88			return -EINVAL;
 89		*size = of_read_number(dma_window, cells);
 90		dma_window += cells;
 91
 92		if (cur_index++ == index)
 93			break;
 94	}
 95	return 0;
 96}
 97EXPORT_SYMBOL_GPL(of_get_dma_window);
 98
 99static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
100{
101	struct of_phandle_args *iommu_spec = data;
102
103	iommu_spec->args[0] = alias;
104	return iommu_spec->np == pdev->bus->dev.of_node;
105}
106
107static const struct iommu_ops
108*of_pci_iommu_configure(struct pci_dev *pdev, struct device_node *bridge_np)
109{
110	const struct iommu_ops *ops;
111	struct of_phandle_args iommu_spec;
112
113	/*
114	 * Start by tracing the RID alias down the PCI topology as
115	 * far as the host bridge whose OF node we have...
116	 * (we're not even attempting to handle multi-alias devices yet)
117	 */
118	iommu_spec.args_count = 1;
119	iommu_spec.np = bridge_np;
120	pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
121	/*
122	 * ...then find out what that becomes once it escapes the PCI
123	 * bus into the system beyond, and which IOMMU it ends up at.
124	 */
125	iommu_spec.np = NULL;
126	if (of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
127			   "iommu-map-mask", &iommu_spec.np, iommu_spec.args))
128		return NULL;
129
130	ops = of_iommu_get_ops(iommu_spec.np);
131	if (!ops || !ops->of_xlate ||
132	    iommu_fwspec_init(&pdev->dev, &iommu_spec.np->fwnode, ops) ||
133	    ops->of_xlate(&pdev->dev, &iommu_spec))
134		ops = NULL;
135
136	of_node_put(iommu_spec.np);
137	return ops;
138}
139
140const struct iommu_ops *of_iommu_configure(struct device *dev,
141					   struct device_node *master_np)
142{
143	struct of_phandle_args iommu_spec;
144	struct device_node *np;
145	const struct iommu_ops *ops = NULL;
146	int idx = 0;
147
148	if (dev_is_pci(dev))
149		return of_pci_iommu_configure(to_pci_dev(dev), master_np);
150
151	/*
152	 * We don't currently walk up the tree looking for a parent IOMMU.
153	 * See the `Notes:' section of
154	 * Documentation/devicetree/bindings/iommu/iommu.txt
155	 */
156	while (!of_parse_phandle_with_args(master_np, "iommus",
157					   "#iommu-cells", idx,
158					   &iommu_spec)) {
159		np = iommu_spec.np;
160		ops = of_iommu_get_ops(np);
161
162		if (!ops || !ops->of_xlate ||
163		    iommu_fwspec_init(dev, &np->fwnode, ops) ||
164		    ops->of_xlate(dev, &iommu_spec))
165			goto err_put_node;
166
167		of_node_put(np);
168		idx++;
169	}
170
171	return ops;
172
173err_put_node:
174	of_node_put(np);
175	return NULL;
176}
177
178static int __init of_iommu_init(void)
179{
180	struct device_node *np;
181	const struct of_device_id *match, *matches = &__iommu_of_table;
182
183	for_each_matching_node_and_match(np, matches, &match) {
184		const of_iommu_init_fn init_fn = match->data;
185
186		if (init_fn(np))
187			pr_err("Failed to initialise IOMMU %s\n",
188				of_node_full_name(np));
189	}
190
191	return 0;
192}
193postcore_initcall_sync(of_iommu_init);