blob: 12cc6485b2185c4eae5399adbda4598da619a1dd [file] [log] [blame]
Vineet Gupta1162b072013-01-18 15:12:20 +05301/*
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 */
29void *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}
44EXPORT_SYMBOL(dma_alloc_noncoherent);
45
46void 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}
52EXPORT_SYMBOL(dma_free_noncoherent);
53
54void *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}
74EXPORT_SYMBOL(dma_alloc_coherent);
75
76void 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}
84EXPORT_SYMBOL(dma_free_coherent);
85
86/*
87 * Helper for streaming DMA...
88 */
89void __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}
94EXPORT_SYMBOL(__arc_dma_cache_sync);