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 <asm/io.h>
19
20void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
21{
22	void *ret;
23
24	ret = consistent_alloc(gfp, size, dma_handle);
25	if (ret)
26		memset(ret, 0, size);
27
28	return ret;
29}
30
31EXPORT_SYMBOL(dma_alloc_coherent);
32
33void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
34{
35	consistent_free(vaddr);
36}
37
38EXPORT_SYMBOL(dma_free_coherent);
39
40/*
41 * Map a single buffer of the indicated size for DMA in streaming mode.
42 * The 32-bit bus address to use is returned.
43 *
44 * Once the device is given the dma address, the device owns this memory
45 * until either pci_unmap_single or pci_dma_sync_single is performed.
46 */
47dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
48			  enum dma_data_direction direction)
49{
50	if (direction == DMA_NONE)
51                BUG();
52
53	frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
54
55	return virt_to_bus(ptr);
56}
57
58EXPORT_SYMBOL(dma_map_single);
59
60/*
61 * Map a set of buffers described by scatterlist in streaming
62 * mode for DMA.  This is the scather-gather version of the
63 * above pci_map_single interface.  Here the scatter gather list
64 * elements are each tagged with the appropriate dma address
65 * and length.  They are obtained via sg_dma_{address,length}(SG).
66 *
67 * NOTE: An implementation may be able to use a smaller number of
68 *       DMA address/length pairs than there are SG table elements.
69 *       (for example via virtual mapping capabilities)
70 *       The routine returns the number of addr/length pairs actually
71 *       used, at most nents.
72 *
73 * Device ownership issues as mentioned above for pci_map_single are
74 * the same here.
75 */
76int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
77	       enum dma_data_direction direction)
78{
79	unsigned long dampr2;
80	void *vaddr;
81	int i;
82
83	if (direction == DMA_NONE)
84                BUG();
85
86	dampr2 = __get_DAMPR(2);
87
88	for (i = 0; i < nents; i++) {
89		vaddr = kmap_atomic(sg[i].page, __KM_CACHE);
90
91		frv_dcache_writeback((unsigned long) vaddr,
92				     (unsigned long) vaddr + PAGE_SIZE);
93
94	}
95
96	kunmap_atomic(vaddr, __KM_CACHE);
97	if (dampr2) {
98		__set_DAMPR(2, dampr2);
99		__set_IAMPR(2, dampr2);
100	}
101
102	return nents;
103}
104
105EXPORT_SYMBOL(dma_map_sg);
106
107dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
108			size_t size, enum dma_data_direction direction)
109{
110	BUG_ON(direction == DMA_NONE);
111	flush_dcache_page(page);
112	return (dma_addr_t) page_to_phys(page) + offset;
113}
114
115EXPORT_SYMBOL(dma_map_page);
116