1 /* pci-dma.c: Dynamic DMA mapping support for the FRV CPUs that have MMUs
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #include <linux/types.h>
13 #include <linux/slab.h>
14 #include <linux/dma-mapping.h>
15 #include <linux/list.h>
16 #include <linux/pci.h>
17 #include <linux/highmem.h>
18 #include <linux/scatterlist.h>
19 #include <asm/io.h>
20
dma_alloc_coherent(struct device * hwdev,size_t size,dma_addr_t * dma_handle,gfp_t gfp)21 void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
22 {
23 void *ret;
24
25 ret = consistent_alloc(gfp, size, dma_handle);
26 if (ret)
27 memset(ret, 0, size);
28
29 return ret;
30 }
31
32 EXPORT_SYMBOL(dma_alloc_coherent);
33
dma_free_coherent(struct device * hwdev,size_t size,void * vaddr,dma_addr_t dma_handle)34 void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
35 {
36 consistent_free(vaddr);
37 }
38
39 EXPORT_SYMBOL(dma_free_coherent);
40
41 /*
42 * Map a single buffer of the indicated size for DMA in streaming mode.
43 * The 32-bit bus address to use is returned.
44 *
45 * Once the device is given the dma address, the device owns this memory
46 * until either pci_unmap_single or pci_dma_sync_single is performed.
47 */
dma_map_single(struct device * dev,void * ptr,size_t size,enum dma_data_direction direction)48 dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
49 enum dma_data_direction direction)
50 {
51 if (direction == DMA_NONE)
52 BUG();
53
54 frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
55
56 return virt_to_bus(ptr);
57 }
58
59 EXPORT_SYMBOL(dma_map_single);
60
61 /*
62 * Map a set of buffers described by scatterlist in streaming
63 * mode for DMA. This is the scather-gather version of the
64 * above dma_map_single interface. Here the scatter gather list
65 * elements are each tagged with the appropriate dma address
66 * and length. They are obtained via sg_dma_{address,length}(SG).
67 *
68 * NOTE: An implementation may be able to use a smaller number of
69 * DMA address/length pairs than there are SG table elements.
70 * (for example via virtual mapping capabilities)
71 * The routine returns the number of addr/length pairs actually
72 * used, at most nents.
73 *
74 * Device ownership issues as mentioned above for dma_map_single are
75 * the same here.
76 */
dma_map_sg(struct device * dev,struct scatterlist * sg,int nents,enum dma_data_direction direction)77 int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
78 enum dma_data_direction direction)
79 {
80 unsigned long dampr2;
81 void *vaddr;
82 int i;
83
84 if (direction == DMA_NONE)
85 BUG();
86
87 dampr2 = __get_DAMPR(2);
88
89 for (i = 0; i < nents; i++) {
90 vaddr = kmap_atomic(sg_page(&sg[i]), __KM_CACHE);
91
92 frv_dcache_writeback((unsigned long) vaddr,
93 (unsigned long) vaddr + PAGE_SIZE);
94
95 }
96
97 kunmap_atomic(vaddr, __KM_CACHE);
98 if (dampr2) {
99 __set_DAMPR(2, dampr2);
100 __set_IAMPR(2, dampr2);
101 }
102
103 return nents;
104 }
105
106 EXPORT_SYMBOL(dma_map_sg);
107
108 /*
109 * Map a single page of the indicated size for DMA in streaming mode.
110 * The 32-bit bus address to use is returned.
111 *
112 * Device ownership issues as mentioned above for dma_map_single are
113 * the same here.
114 */
dma_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction direction)115 dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
116 size_t size, enum dma_data_direction direction)
117 {
118 BUG_ON(direction == DMA_NONE);
119 flush_dcache_page(page);
120 return (dma_addr_t) page_to_phys(page) + offset;
121 }
122
123 EXPORT_SYMBOL(dma_map_page);
124