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consistent.c
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1 /*
2  * arch/sh/mm/consistent.c
3  *
4  * Copyright (C) 2004 - 2007 Paul Mundt
5  *
6  * Declared coherent memory functions based on arch/x86/kernel/pci-dma_32.c
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License. See the file "COPYING" in the main directory of this archive
10  * for more details.
11  */
12 #include <linux/mm.h>
13 #include <linux/init.h>
14 #include <linux/platform_device.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/dma-debug.h>
17 #include <linux/io.h>
18 #include <linux/module.h>
19 #include <linux/gfp.h>
20 #include <asm/cacheflush.h>
21 #include <asm/addrspace.h>
22 
23 #define PREALLOC_DMA_DEBUG_ENTRIES 4096
24 
26 EXPORT_SYMBOL(dma_ops);
27 
28 static int __init dma_init(void)
29 {
31  return 0;
32 }
34 
35 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
37  struct dma_attrs *attrs)
38 {
39  void *ret, *ret_nocache;
40  int order = get_order(size);
41 
42  gfp |= __GFP_ZERO;
43 
44  ret = (void *)__get_free_pages(gfp, order);
45  if (!ret)
46  return NULL;
47 
48  /*
49  * Pages from the page allocator may have data present in
50  * cache. So flush the cache before using uncached memory.
51  */
52  dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
53 
54  ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size);
55  if (!ret_nocache) {
56  free_pages((unsigned long)ret, order);
57  return NULL;
58  }
59 
61 
62  *dma_handle = virt_to_phys(ret);
63 
64  return ret_nocache;
65 }
66 
69  struct dma_attrs *attrs)
70 {
71  int order = get_order(size);
72  unsigned long pfn = dma_handle >> PAGE_SHIFT;
73  int k;
74 
75  for (k = 0; k < (1 << order); k++)
76  __free_pages(pfn_to_page(pfn + k), 0);
77 
78  iounmap(vaddr);
79 }
80 
81 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
83 {
84  void *addr;
85 
86  addr = __in_29bit_mode() ?
87  (void *)CAC_ADDR((unsigned long)vaddr) : vaddr;
88 
89  switch (direction) {
90  case DMA_FROM_DEVICE: /* invalidate only */
91  __flush_invalidate_region(addr, size);
92  break;
93  case DMA_TO_DEVICE: /* writeback only */
94  __flush_wback_region(addr, size);
95  break;
96  case DMA_BIDIRECTIONAL: /* writeback and invalidate */
97  __flush_purge_region(addr, size);
98  break;
99  default:
100  BUG();
101  }
102 }
104 
105 static int __init memchunk_setup(char *str)
106 {
107  return 1; /* accept anything that begins with "memchunk." */
108 }
109 __setup("memchunk.", memchunk_setup);
110 
111 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
112 {
113  char *p = boot_command_line;
114  int k = strlen(name);
115 
116  while ((p = strstr(p, "memchunk."))) {
117  p += 9; /* strlen("memchunk.") */
118  if (!strncmp(name, p, k) && p[k] == '=') {
119  p += k + 1;
120  *sizep = memparse(p, NULL);
121  pr_info("%s: forcing memory chunk size to 0x%08lx\n",
122  name, *sizep);
123  break;
124  }
125  }
126 }
127 
129  char *name, unsigned long memsize)
130 {
131  struct resource *r;
133  void *buf;
134 
135  r = pdev->resource + pdev->num_resources - 1;
136  if (r->flags) {
137  pr_warning("%s: unable to find empty space for resource\n",
138  name);
139  return -EINVAL;
140  }
141 
142  memchunk_cmdline_override(name, &memsize);
143  if (!memsize)
144  return 0;
145 
146  buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
147  if (!buf) {
148  pr_warning("%s: unable to allocate memory\n", name);
149  return -ENOMEM;
150  }
151 
152  memset(buf, 0, memsize);
153 
154  r->flags = IORESOURCE_MEM;
155  r->start = dma_handle;
156  r->end = r->start + memsize - 1;
157  r->name = name;
158  return 0;
159 }