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20e9969b DB |
1 | /* |
2 | * mach-davinci/sram.c - DaVinci simple SRAM allocator | |
3 | * | |
4 | * Copyright (C) 2009 David Brownell | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | */ | |
11 | #include <linux/module.h> | |
20e9969b DB |
12 | #include <linux/init.h> |
13 | #include <linux/genalloc.h> | |
14 | ||
15 | #include <mach/common.h> | |
20e9969b DB |
16 | #include <mach/sram.h> |
17 | ||
20e9969b DB |
18 | static struct gen_pool *sram_pool; |
19 | ||
20 | void *sram_alloc(size_t len, dma_addr_t *dma) | |
21 | { | |
22 | unsigned long vaddr; | |
23 | dma_addr_t dma_base = davinci_soc_info.sram_dma; | |
24 | ||
25 | if (dma) | |
26 | *dma = 0; | |
27 | if (!sram_pool || (dma && !dma_base)) | |
28 | return NULL; | |
29 | ||
30 | vaddr = gen_pool_alloc(sram_pool, len); | |
31 | if (!vaddr) | |
32 | return NULL; | |
33 | ||
34 | if (dma) | |
35 | *dma = dma_base + (vaddr - SRAM_VIRT); | |
36 | return (void *)vaddr; | |
37 | ||
38 | } | |
39 | EXPORT_SYMBOL(sram_alloc); | |
40 | ||
41 | void sram_free(void *addr, size_t len) | |
42 | { | |
43 | gen_pool_free(sram_pool, (unsigned long) addr, len); | |
44 | } | |
45 | EXPORT_SYMBOL(sram_free); | |
46 | ||
47 | ||
48 | /* | |
49 | * REVISIT This supports CPU and DMA access to/from SRAM, but it | |
50 | * doesn't (yet?) support some other notable uses of SRAM: as TCM | |
51 | * for data and/or instructions; and holding code needed to enter | |
52 | * and exit suspend states (while DRAM can't be used). | |
53 | */ | |
54 | static int __init sram_init(void) | |
55 | { | |
56 | unsigned len = davinci_soc_info.sram_len; | |
57 | int status = 0; | |
58 | ||
59 | if (len) { | |
1d3bba61 | 60 | len = min_t(unsigned, len, SRAM_SIZE); |
20e9969b DB |
61 | sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1); |
62 | if (!sram_pool) | |
63 | status = -ENOMEM; | |
64 | } | |
65 | if (sram_pool) | |
66 | status = gen_pool_add(sram_pool, SRAM_VIRT, len, -1); | |
67 | WARN_ON(status < 0); | |
68 | return status; | |
69 | } | |
70 | core_initcall(sram_init); | |
71 |