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4e0ee78f HD |
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/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 | */ | |
38 | int 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 | } | |
90 | EXPORT_SYMBOL_GPL(of_get_dma_window); |