]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - arch/arc/mm/dma.c
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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.
10 * DMA Coherent API Notes
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.
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}
21 #include <linux/dma-mapping.h>
22 #include <linux/dma-debug.h>
23 #include <linux/export.h>
24 #include <asm/cacheflush.h>
27 * Helpers for Coherent DMA API.
29 void *dma_alloc_noncoherent(struct device
*dev
, size_t size
,
30 dma_addr_t
*dma_handle
, gfp_t gfp
)
34 /* This is linear addr (0x8000_0000 based) */
35 paddr
= alloc_pages_exact(size
, gfp
);
39 /* This is bus address, platform dependent */
40 *dma_handle
= plat_kernel_addr_to_dma(dev
, paddr
);
44 EXPORT_SYMBOL(dma_alloc_noncoherent
);
46 void dma_free_noncoherent(struct device
*dev
, size_t size
, void *vaddr
,
47 dma_addr_t dma_handle
)
49 free_pages_exact((void *)plat_dma_addr_to_kernel(dev
, dma_handle
),
52 EXPORT_SYMBOL(dma_free_noncoherent
);
54 void *dma_alloc_coherent(struct device
*dev
, size_t size
,
55 dma_addr_t
*dma_handle
, gfp_t gfp
)
59 /* This is linear addr (0x8000_0000 based) */
60 paddr
= alloc_pages_exact(size
, gfp
);
64 /* This is kernel Virtual address (0x7000_0000 based) */
65 kvaddr
= ioremap_nocache((unsigned long)paddr
, size
);
67 memset(kvaddr
, 0, size
);
69 /* This is bus address, platform dependent */
70 *dma_handle
= plat_kernel_addr_to_dma(dev
, paddr
);
74 EXPORT_SYMBOL(dma_alloc_coherent
);
76 void dma_free_coherent(struct device
*dev
, size_t size
, void *kvaddr
,
77 dma_addr_t dma_handle
)
79 iounmap((void __force __iomem
*)kvaddr
);
81 free_pages_exact((void *)plat_dma_addr_to_kernel(dev
, dma_handle
),
84 EXPORT_SYMBOL(dma_free_coherent
);
87 * Helper for streaming DMA...
89 void __arc_dma_cache_sync(unsigned long paddr
, size_t size
,
90 enum dma_data_direction dir
)
92 __inline_dma_cache_sync(paddr
, size
, dir
);
94 EXPORT_SYMBOL(__arc_dma_cache_sync
);