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 const struct dma_map_ops *dma_ops;
  24 EXPORT_SYMBOL(dma_ops);
  25
  26 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
  27                                  dma_addr_t *dma_handle, gfp_t gfp,
  28                                  unsigned long attrs)
  29 {
  30         void *ret, *ret_nocache;
  31         int order = get_order(size);
  32
  33         gfp |= __GFP_ZERO;
  34
  35         ret = (void *)__get_free_pages(gfp, order);
  36         if (!ret)
  37                 return NULL;
  38
  39         /*
  40          * Pages from the page allocator may have data present in
  41          * cache. So flush the cache before using uncached memory.
  42          */
  43         sh_sync_dma_for_device(ret, size, DMA_BIDIRECTIONAL);
  44
  45         ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size);
  46         if (!ret_nocache) {
  47                 free_pages((unsigned long)ret, order);
  48                 return NULL;
  49         }
  50
  51         split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
  52
  53         *dma_handle = virt_to_phys(ret);
  54         if (!WARN_ON(!dev))
  55                 *dma_handle -= PFN_PHYS(dev->dma_pfn_offset);
  56
  57         return ret_nocache;
  58 }
  59
  60 void dma_generic_free_coherent(struct device *dev, size_t size,
  61                                void *vaddr, dma_addr_t dma_handle,
  62                                unsigned long attrs)
  63 {
  64         int order = get_order(size);
  65         unsigned long pfn = dma_handle >> PAGE_SHIFT;
  66         int k;
  67
  68         if (!WARN_ON(!dev))
  69                 pfn += dev->dma_pfn_offset;
  70
  71         for (k = 0; k < (1 << order); k++)
  72                 __free_pages(pfn_to_page(pfn + k), 0);
  73
  74         iounmap(vaddr);
  75 }
  76
  77 void sh_sync_dma_for_device(void *vaddr, size_t size,
  78                     enum dma_data_direction direction)
  79 {
  80         void *addr;
  81
  82         addr = __in_29bit_mode() ?
  83                (void *)CAC_ADDR((unsigned long)vaddr) : vaddr;
  84
  85         switch (direction) {
  86         case DMA_FROM_DEVICE:           /* invalidate only */
  87                 __flush_invalidate_region(addr, size);
  88                 break;
  89         case DMA_TO_DEVICE:             /* writeback only */
  90                 __flush_wback_region(addr, size);
  91                 break;
  92         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  93                 __flush_purge_region(addr, size);
  94                 break;
  95         default:
  96                 BUG();
  97         }
  98 }
  99 EXPORT_SYMBOL(sh_sync_dma_for_device);
 100
 101 static int __init memchunk_setup(char *str)
 102 {
 103         return 1; /* accept anything that begins with "memchunk." */
 104 }
 105 __setup("memchunk.", memchunk_setup);
 106
 107 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
 108 {
 109         char *p = boot_command_line;
 110         int k = strlen(name);
 111
 112         while ((p = strstr(p, "memchunk."))) {
 113                 p += 9; /* strlen("memchunk.") */
 114                 if (!strncmp(name, p, k) && p[k] == '=') {
 115                         p += k + 1;
 116                         *sizep = memparse(p, NULL);
 117                         pr_info("%s: forcing memory chunk size to 0x%08lx\n",
 118                                 name, *sizep);
 119                         break;
 120                 }
 121         }
 122 }
 123
 124 int __init platform_resource_setup_memory(struct platform_device *pdev,
 125                                           char *name, unsigned long memsize)
 126 {
 127         struct resource *r;
 128         dma_addr_t dma_handle;
 129         void *buf;
 130
 131         r = pdev->resource + pdev->num_resources - 1;
 132         if (r->flags) {
 133                 pr_warning("%s: unable to find empty space for resource\n",
 134                         name);
 135                 return -EINVAL;
 136         }
 137
 138         memchunk_cmdline_override(name, &memsize);
 139         if (!memsize)
 140                 return 0;
 141
 142         buf = dma_alloc_coherent(&pdev->dev, memsize, &dma_handle, GFP_KERNEL);
 143         if (!buf) {
 144                 pr_warning("%s: unable to allocate memory\n", name);
 145                 return -ENOMEM;
 146         }
 147
 148         memset(buf, 0, memsize);
 149
 150         r->flags = IORESOURCE_MEM;
 151         r->start = dma_handle;
 152         r->end = r->start + memsize - 1;
 153         r->name = name;
 154         return 0;
 155 }