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         *dma_handle = virt_to_phys(ret);
  46         return ret_nocache;
  47 }
  48 EXPORT_SYMBOL(dma_alloc_coherent);
  49
  50 void dma_free_coherent(struct device *dev, size_t size,
  51                          void *vaddr, dma_addr_t dma_handle)
  52 {
  53         int order = get_order(size);
  54
  55         if (!dma_release_from_coherent(dev, order, vaddr)) {
  56                 WARN_ON(irqs_disabled());       /* for portability */
  57                 free_pages((unsigned long)phys_to_virt(dma_handle), order);
  58                 iounmap(vaddr);
  59         }
  60 }
  61 EXPORT_SYMBOL(dma_free_coherent);
  62
  63 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
  64                     enum dma_data_direction direction)
  65 {
  66 #ifdef CONFIG_CPU_SH5
  67         void *p1addr = vaddr;
  68 #else
  69         void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
  70 #endif
  71
  72         switch (direction) {
  73         case DMA_FROM_DEVICE:           /* invalidate only */
  74                 __flush_invalidate_region(p1addr, size);
  75                 break;
  76         case DMA_TO_DEVICE:             /* writeback only */
  77                 __flush_wback_region(p1addr, size);
  78                 break;
  79         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  80                 __flush_purge_region(p1addr, size);
  81                 break;
  82         default:
  83                 BUG();
  84         }
  85 }
  86 EXPORT_SYMBOL(dma_cache_sync);
  87
  88 static int __init memchunk_setup(char *str)
  89 {
  90         return 1; /* accept anything that begins with "memchunk." */
  91 }
  92 __setup("memchunk.", memchunk_setup);
  93
  94 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
  95 {
  96         char *p = boot_command_line;
  97         int k = strlen(name);
  98
  99         while ((p = strstr(p, "memchunk."))) {
 100                 p += 9; /* strlen("memchunk.") */
 101                 if (!strncmp(name, p, k) && p[k] == '=') {
 102                         p += k + 1;
 103                         *sizep = memparse(p, NULL);
 104                         pr_info("%s: forcing memory chunk size to 0x%08lx\n",
 105                                 name, *sizep);
 106                         break;
 107                 }
 108         }
 109 }
 110
 111 int __init platform_resource_setup_memory(struct platform_device *pdev,
 112                                           char *name, unsigned long memsize)
 113 {
 114         struct resource *r;
 115         dma_addr_t dma_handle;
 116         void *buf;
 117
 118         r = pdev->resource + pdev->num_resources - 1;
 119         if (r->flags) {
 120                 pr_warning("%s: unable to find empty space for resource\n",
 121                         name);
 122                 return -EINVAL;
 123         }
 124
 125         memchunk_cmdline_override(name, &memsize);
 126         if (!memsize)
 127                 return 0;
 128
 129         buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
 130         if (!buf) {
 131                 pr_warning("%s: unable to allocate memory\n", name);
 132                 return -ENOMEM;
 133         }
 134
 135         memset(buf, 0, memsize);
 136
 137         r->flags = IORESOURCE_MEM;
 138         r->start = dma_handle;
 139         r->end = r->start + memsize - 1;
 140         r->name = name;
 141         return 0;
 142 }