blob: ee249bc959f84bb2bc50eb652ea1b34d449db77a [file] [log] [blame]
Hiroshi Doyu4e0ee782012-06-25 14:23:54 +03001/*
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/limits.h>
22#include <linux/of.h>
23
24/**
25 * of_get_dma_window - Parse *dma-window property and returns 0 if found.
26 *
27 * @dn: device node
28 * @prefix: prefix for property name if any
29 * @index: index to start to parse
30 * @busno: Returns busno if supported. Otherwise pass NULL
31 * @addr: Returns address that DMA starts
32 * @size: Returns the range that DMA can handle
33 *
34 * This supports different formats flexibly. "prefix" can be
35 * configured if any. "busno" and "index" are optionally
36 * specified. Set 0(or NULL) if not used.
37 */
38int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
39 unsigned long *busno, dma_addr_t *addr, size_t *size)
40{
41 const __be32 *dma_window, *end;
42 int bytes, cur_index = 0;
43 char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];
44
45 if (!dn || !addr || !size)
46 return -EINVAL;
47
48 if (!prefix)
49 prefix = "";
50
51 snprintf(propname, sizeof(propname), "%sdma-window", prefix);
52 snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);
53 snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);
54
55 dma_window = of_get_property(dn, propname, &bytes);
56 if (!dma_window)
57 return -ENODEV;
58 end = dma_window + bytes / sizeof(*dma_window);
59
60 while (dma_window < end) {
61 u32 cells;
62 const void *prop;
63
64 /* busno is one cell if supported */
65 if (busno)
66 *busno = be32_to_cpup(dma_window++);
67
68 prop = of_get_property(dn, addrname, NULL);
69 if (!prop)
70 prop = of_get_property(dn, "#address-cells", NULL);
71
72 cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
73 if (!cells)
74 return -EINVAL;
75 *addr = of_read_number(dma_window, cells);
76 dma_window += cells;
77
78 prop = of_get_property(dn, sizename, NULL);
79 cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
80 if (!cells)
81 return -EINVAL;
82 *size = of_read_number(dma_window, cells);
83 dma_window += cells;
84
85 if (cur_index++ == index)
86 break;
87 }
88 return 0;
89}
90EXPORT_SYMBOL_GPL(of_get_dma_window);