kernel/2.6.29.6-aldebaran-rt/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/platform_device.h>
  14 #include <linux/dma-mapping.h>
  15 #include <asm/cacheflush.h>
  16 #include <asm/addrspace.h>
  17 #include <asm/io.h>
  18
  19 void *dma_alloc_coherent(struct device *dev, size_t size,
  20                            dma_addr_t *dma_handle, gfp_t gfp)
  21 {
  22         void *ret, *ret_nocache;
  23         int order = get_order(size);
  24
  25         if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
  26                 return ret;
  27
  28         ret = (void *)__get_free_pages(gfp, order);
  29         if (!ret)
  30                 return NULL;
  31
  32         memset(ret, 0, size);
  33         /*
  34          * Pages from the page allocator may have data present in
  35          * cache. So flush the cache before using uncached memory.
  36          */
  37         dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
  38
  39         ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size);
  40         if (!ret_nocache) {
  41                 free_pages((unsigned long)ret, order);
  42                 return NULL;
  43         }
  44
  45         split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
  46
  47         *dma_handle = virt_to_phys(ret);
  48         return ret_nocache;
  49 }
  50 EXPORT_SYMBOL(dma_alloc_coherent);
  51
  52 void dma_free_coherent(struct device *dev, size_t size,
  53                          void *vaddr, dma_addr_t dma_handle)
  54 {
  55         int order = get_order(size);
  56         unsigned long pfn = dma_handle >> PAGE_SHIFT;
  57         int k;
  58
  59         if (!dma_release_from_coherent(dev, order, vaddr)) {
  60                 WARN_ON(irqs_disabled());       /* for portability */
  61                 for (k = 0; k < (1 << order); k++)
  62                         __free_pages(pfn_to_page(pfn + k), 0);
  63                 iounmap(vaddr);
  64         }
  65 }
  66 EXPORT_SYMBOL(dma_free_coherent);
  67
  68 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
  69                     enum dma_data_direction direction)
  70 {
  71 #ifdef CONFIG_CPU_SH5
  72         void *p1addr = vaddr;
  73 #else
  74         void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
  75 #endif
  76
  77         switch (direction) {
  78         case DMA_FROM_DEVICE:           /* invalidate only */
  79                 __flush_invalidate_region(p1addr, size);
  80                 break;
  81         case DMA_TO_DEVICE:             /* writeback only */
  82                 __flush_wback_region(p1addr, size);
  83                 break;
  84         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  85                 __flush_purge_region(p1addr, size);
  86                 break;
  87         default:
  88                 BUG();
  89         }
  90 }
  91 EXPORT_SYMBOL(dma_cache_sync);
  92
  93 static int __init memchunk_setup(char *str)
  94 {
  95         return 1; /* accept anything that begins with "memchunk." */
  96 }
  97 __setup("memchunk.", memchunk_setup);
  98
  99 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
 100 {
 101         char *p = boot_command_line;
 102         int k = strlen(name);
 103
 104         while ((p = strstr(p, "memchunk."))) {
 105                 p += 9; /* strlen("memchunk.") */
 106                 if (!strncmp(name, p, k) && p[k] == '=') {
 107                         p += k + 1;
 108                         *sizep = memparse(p, NULL);
 109                         pr_info("%s: forcing memory chunk size to 0x%08lx\n",
 110                                 name, *sizep);
 111                         break;
 112                 }
 113         }
 114 }
 115
 116 int __init platform_resource_setup_memory(struct platform_device *pdev,
 117                                           char *name, unsigned long memsize)
 118 {
 119         struct resource *r;
 120         dma_addr_t dma_handle;
 121         void *buf;
 122
 123         r = pdev->resource + pdev->num_resources - 1;
 124         if (r->flags) {
 125                 pr_warning("%s: unable to find empty space for resource\n",
 126                         name);
 127                 return -EINVAL;
 128         }
 129
 130         memchunk_cmdline_override(name, &memsize);
 131         if (!memsize)
 132                 return 0;
 133
 134         buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
 135         if (!buf) {
 136                 pr_warning("%s: unable to allocate memory\n", name);
 137                 return -ENOMEM;
 138         }
 139
 140         memset(buf, 0, memsize);
 141
 142         r->flags = IORESOURCE_MEM;
 143         r->start = dma_handle;
 144         r->end = r->start + memsize - 1;
 145         r->name = name;
 146         return 0;
 147 }