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 <asm/cacheflush.h>
  19 #include <asm/addrspace.h>
  20
  21 #define PREALLOC_DMA_DEBUG_ENTRIES      4096
  22
  23 static int __init dma_init(void)
  24 {
  25         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
  26         return 0;
  27 }
  28 fs_initcall(dma_init);
  29
  30 void *dma_alloc_coherent(struct device *dev, size_t size,
  31                            dma_addr_t *dma_handle, gfp_t gfp)
  32 {
  33         void *ret, *ret_nocache;
  34         int order = get_order(size);
  35
  36         if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
  37                 return ret;
  38
  39         ret = (void *)__get_free_pages(gfp, order);
  40         if (!ret)
  41                 return NULL;
  42
  43         memset(ret, 0, size);
  44         /*
  45          * Pages from the page allocator may have data present in
  46          * cache. So flush the cache before using uncached memory.
  47          */
  48         dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
  49
  50         ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size);
  51         if (!ret_nocache) {
  52                 free_pages((unsigned long)ret, order);
  53                 return NULL;
  54         }
  55
  56         split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
  57
  58         *dma_handle = virt_to_phys(ret);
  59
  60         debug_dma_alloc_coherent(dev, size, *dma_handle, ret_nocache);
  61
  62         return ret_nocache;
  63 }
  64 EXPORT_SYMBOL(dma_alloc_coherent);
  65
  66 void dma_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         WARN_ON(irqs_disabled());       /* for portability */
  74
  75         if (dma_release_from_coherent(dev, order, vaddr))
  76                 return;
  77
  78         debug_dma_free_coherent(dev, size, vaddr, dma_handle);
  79         for (k = 0; k < (1 << order); k++)
  80                 __free_pages(pfn_to_page(pfn + k), 0);
  81         iounmap(vaddr);
  82 }
  83 EXPORT_SYMBOL(dma_free_coherent);
  84
  85 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
  86                     enum dma_data_direction direction)
  87 {
  88 #ifdef CONFIG_CPU_SH5
  89         void *p1addr = vaddr;
  90 #else
  91         void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
  92 #endif
  93
  94         switch (direction) {
  95         case DMA_FROM_DEVICE:           /* invalidate only */
  96                 __flush_invalidate_region(p1addr, size);
  97                 break;
  98         case DMA_TO_DEVICE:             /* writeback only */
  99                 __flush_wback_region(p1addr, size);
 100                 break;
 101         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
 102                 __flush_purge_region(p1addr, size);
 103                 break;
 104         default:
 105                 BUG();
 106         }
 107 }
 108 EXPORT_SYMBOL(dma_cache_sync);
 109
 110 static int __init memchunk_setup(char *str)
 111 {
 112         return 1; /* accept anything that begins with "memchunk." */
 113 }
 114 __setup("memchunk.", memchunk_setup);
 115
 116 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
 117 {
 118         char *p = boot_command_line;
 119         int k = strlen(name);
 120
 121         while ((p = strstr(p, "memchunk."))) {
 122                 p += 9; /* strlen("memchunk.") */
 123                 if (!strncmp(name, p, k) && p[k] == '=') {
 124                         p += k + 1;
 125                         *sizep = memparse(p, NULL);
 126                         pr_info("%s: forcing memory chunk size to 0x%08lx\n",
 127                                 name, *sizep);
 128                         break;
 129                 }
 130         }
 131 }
 132
 133 int __init platform_resource_setup_memory(struct platform_device *pdev,
 134                                           char *name, unsigned long memsize)
 135 {
 136         struct resource *r;
 137         dma_addr_t dma_handle;
 138         void *buf;
 139
 140         r = pdev->resource + pdev->num_resources - 1;
 141         if (r->flags) {
 142                 pr_warning("%s: unable to find empty space for resource\n",
 143                         name);
 144                 return -EINVAL;
 145         }
 146
 147         memchunk_cmdline_override(name, &memsize);
 148         if (!memsize)
 149                 return 0;
 150
 151         buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
 152         if (!buf) {
 153                 pr_warning("%s: unable to allocate memory\n", name);
 154                 return -ENOMEM;
 155         }
 156
 157         memset(buf, 0, memsize);
 158
 159         r->flags = IORESOURCE_MEM;
 160         r->start = dma_handle;
 161         r->end = r->start + memsize - 1;
 162         r->name = name;
 163         return 0;
 164 }