| Vineet Gupta | 1162b07 | 2013-01-18 15:12:20 +0530 | [diff] [blame^] | 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); |