arch/sh/mm/consistent.c

   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
  25 struct dma_map_ops *dma_ops;
  26 EXPORT_SYMBOL(dma_ops);
  27
  28 static int __init dma_init(void)
  29 {
  30         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
  31         return 0;
  32 }
  33 fs_initcall(dma_init);
  34
  35 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
  36                                  dma_addr_t *dma_handle, gfp_t gfp,
  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
  60         split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
  61
  62         *dma_handle = virt_to_phys(ret);
  63
  64         return ret_nocache;
  65 }
  66
  67 void dma_generic_free_coherent(struct device *dev, size_t size,
  68                                void *vaddr, dma_addr_t dma_handle,
  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,
  82                     enum dma_data_direction direction)
  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 }
 103 EXPORT_SYMBOL(dma_cache_sync);
 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
 128 int __init platform_resource_setup_memory(struct platform_device *pdev,
 129                                           char *name, unsigned long memsize)
 130 {
 131         struct resource *r;
 132         dma_addr_t dma_handle;
 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 }