| Hiroshi Doyu | 4e0ee78 | 2012-06-25 14:23:54 +0300 | [diff] [blame] | 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); |