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 {
  38         void *ret, *ret_nocache;
  39         int order = get_order(size);
  40
  41         gfp |= __GFP_ZERO;
  42
  43         ret = (void *)__get_free_pages(gfp, order);
  44         if (!ret)
  45                 return NULL;
  46
  47         /*
  48          * Pages from the page allocator may have data present in
  49          * cache. So flush the cache before using uncached memory.
  50          */
  51         dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
  52
  53         ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size);
  54         if (!ret_nocache) {
  55                 free_pages((unsigned long)ret, order);
  56                 return NULL;
  57         }
  58
  59         split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
  60
  61         *dma_handle = virt_to_phys(ret);
  62
  63         return ret_nocache;
  64 }
  65
  66 void dma_generic_free_coherent(struct device *dev, size_t size,
  67                                void *vaddr, dma_addr_t dma_handle)
  68 {
  69         int order = get_order(size);
  70         unsigned long pfn = dma_handle >> PAGE_SHIFT;
  71         int k;
  72
  73         for (k = 0; k < (1 << order); k++)
  74                 __free_pages(pfn_to_page(pfn + k), 0);
  75
  76         iounmap(vaddr);
  77 }
  78
  79 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
  80                     enum dma_data_direction direction)
  81 {
  82         void *addr;
  83
  84         addr = __in_29bit_mode() ?
  85                (void *)P1SEGADDR((unsigned long)vaddr) : vaddr;
  86
  87         switch (direction) {
  88         case DMA_FROM_DEVICE:           /* invalidate only */
  89                 __flush_invalidate_region(addr, size);
  90                 break;
  91         case DMA_TO_DEVICE:             /* writeback only */
  92                 __flush_wback_region(addr, size);
  93                 break;
  94         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  95                 __flush_purge_region(addr, size);
  96                 break;
  97         default:
  98                 BUG();
  99         }
 100 }
 101 EXPORT_SYMBOL(dma_cache_sync);
 102
 103 static int __init memchunk_setup(char *str)
 104 {
 105         return 1; /* accept anything that begins with "memchunk." */
 106 }
 107 __setup("memchunk.", memchunk_setup);
 108
 109 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
 110 {
 111         char *p = boot_command_line;
 112         int k = strlen(name);
 113
 114         while ((p = strstr(p, "memchunk."))) {
 115                 p += 9; /* strlen("memchunk.") */
 116                 if (!strncmp(name, p, k) && p[k] == '=') {
 117                         p += k + 1;
 118                         *sizep = memparse(p, NULL);
 119                         pr_info("%s: forcing memory chunk size to 0x%08lx\n",
 120                                 name, *sizep);
 121                         break;
 122                 }
 123         }
 124 }
 125
 126 int __init platform_resource_setup_memory(struct platform_device *pdev,
 127                                           char *name, unsigned long memsize)
 128 {
 129         struct resource *r;
 130         dma_addr_t dma_handle;
 131         void *buf;
 132
 133         r = pdev->resource + pdev->num_resources - 1;
 134         if (r->flags) {
 135                 pr_warning("%s: unable to find empty space for resource\n",
 136                         name);
 137                 return -EINVAL;
 138         }
 139
 140         memchunk_cmdline_override(name, &memsize);
 141         if (!memsize)
 142                 return 0;
 143
 144         buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
 145         if (!buf) {
 146                 pr_warning("%s: unable to allocate memory\n", name);
 147                 return -ENOMEM;
 148         }
 149
 150         memset(buf, 0, memsize);
 151
 152         r->flags = IORESOURCE_MEM;
 153         r->start = dma_handle;
 154         r->end = r->start + memsize - 1;
 155         r->name = name;
 156         return 0;
 157 }