Commit | Line | Data |
---|---|---|
1162b070 VG |
1 | /* |
2 | * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | ||
9 | /* | |
10 | * DMA Coherent API Notes | |
11 | * | |
12 | * I/O is inherently non-coherent on ARC. So a coherent DMA buffer is | |
13 | * implemented by accessintg it using a kernel virtual address, with | |
14 | * Cache bit off in the TLB entry. | |
15 | * | |
16 | * The default DMA address == Phy address which is 0x8000_0000 based. | |
17 | * A platform/device can make it zero based, by over-riding | |
18 | * plat_{dma,kernel}_addr_to_{kernel,dma} | |
19 | */ | |
20 | ||
21 | #include <linux/dma-mapping.h> | |
22 | #include <linux/dma-debug.h> | |
23 | #include <linux/export.h> | |
24 | #include <asm/cacheflush.h> | |
25 | ||
26 | /* | |
27 | * Helpers for Coherent DMA API. | |
28 | */ | |
29 | void *dma_alloc_noncoherent(struct device *dev, size_t size, | |
30 | dma_addr_t *dma_handle, gfp_t gfp) | |
31 | { | |
32 | void *paddr; | |
33 | ||
34 | /* This is linear addr (0x8000_0000 based) */ | |
35 | paddr = alloc_pages_exact(size, gfp); | |
36 | if (!paddr) | |
37 | return NULL; | |
38 | ||
39 | /* This is bus address, platform dependent */ | |
40 | *dma_handle = plat_kernel_addr_to_dma(dev, paddr); | |
41 | ||
42 | return paddr; | |
43 | } | |
44 | EXPORT_SYMBOL(dma_alloc_noncoherent); | |
45 | ||
46 | void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr, | |
47 | dma_addr_t dma_handle) | |
48 | { | |
49 | free_pages_exact((void *)plat_dma_addr_to_kernel(dev, dma_handle), | |
50 | size); | |
51 | } | |
52 | EXPORT_SYMBOL(dma_free_noncoherent); | |
53 | ||
54 | void *dma_alloc_coherent(struct device *dev, size_t size, | |
55 | dma_addr_t *dma_handle, gfp_t gfp) | |
56 | { | |
57 | void *paddr, *kvaddr; | |
58 | ||
59 | /* This is linear addr (0x8000_0000 based) */ | |
60 | paddr = alloc_pages_exact(size, gfp); | |
61 | if (!paddr) | |
62 | return NULL; | |
63 | ||
64 | /* This is kernel Virtual address (0x7000_0000 based) */ | |
65 | kvaddr = ioremap_nocache((unsigned long)paddr, size); | |
66 | if (kvaddr != NULL) | |
67 | memset(kvaddr, 0, size); | |
68 | ||
69 | /* This is bus address, platform dependent */ | |
70 | *dma_handle = plat_kernel_addr_to_dma(dev, paddr); | |
71 | ||
72 | return kvaddr; | |
73 | } | |
74 | EXPORT_SYMBOL(dma_alloc_coherent); | |
75 | ||
76 | void dma_free_coherent(struct device *dev, size_t size, void *kvaddr, | |
77 | dma_addr_t dma_handle) | |
78 | { | |
79 | iounmap((void __force __iomem *)kvaddr); | |
80 | ||
81 | free_pages_exact((void *)plat_dma_addr_to_kernel(dev, dma_handle), | |
82 | size); | |
83 | } | |
84 | EXPORT_SYMBOL(dma_free_coherent); | |
85 | ||
86 | /* | |
87 | * Helper for streaming DMA... | |
88 | */ | |
89 | void __arc_dma_cache_sync(unsigned long paddr, size_t size, | |
90 | enum dma_data_direction dir) | |
91 | { | |
92 | __inline_dma_cache_sync(paddr, size, dir); | |
93 | } | |
94 | EXPORT_SYMBOL(__arc_dma_cache_sync); |