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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); |
91 |
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