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 struct dma_coherent_mem {
  20         void            *virt_base;
  21         u32             device_base;
  22         int             size;
  23         int             flags;
  24         unsigned long   *bitmap;
  25 };
  26
  27 void *dma_alloc_coherent(struct device *dev, size_t size,
  28                            dma_addr_t *dma_handle, gfp_t gfp)
  29 {
  30         void *ret, *ret_nocache;
  31         int order = get_order(size);
  32
  33         if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
  34                 return ret;
  35
  36         ret = (void *)__get_free_pages(gfp, order);
  37         if (!ret)
  38                 return NULL;
  39
  40         memset(ret, 0, size);
  41         /*
  42          * Pages from the page allocator may have data present in
  43          * cache. So flush the cache before using uncached memory.
  44          */
  45         dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
  46
  47         ret_nocache = ioremap_nocache(virt_to_phys(ret), size);
  48         if (!ret_nocache) {
  49                 free_pages((unsigned long)ret, order);
  50                 return NULL;
  51         }
  52
  53         *dma_handle = virt_to_phys(ret);
  54         return ret_nocache;
  55 }
  56 EXPORT_SYMBOL(dma_alloc_coherent);
  57
  58 void dma_free_coherent(struct device *dev, size_t size,
  59                          void *vaddr, dma_addr_t dma_handle)
  60 {
  61         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
  62         int order = get_order(size);
  63
  64         if (!dma_release_from_coherent(dev, order, vaddr)) {
  65                 WARN_ON(irqs_disabled());       /* for portability */
  66                 BUG_ON(mem && mem->flags & DMA_MEMORY_EXCLUSIVE);
  67                 free_pages((unsigned long)phys_to_virt(dma_handle), order);
  68                 iounmap(vaddr);
  69         }
  70 }
  71 EXPORT_SYMBOL(dma_free_coherent);
  72
  73 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
  74                     enum dma_data_direction direction)
  75 {
  76 #ifdef CONFIG_CPU_SH5
  77         void *p1addr = vaddr;
  78 #else
  79         void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
  80 #endif
  81
  82         switch (direction) {
  83         case DMA_FROM_DEVICE:           /* invalidate only */
  84                 __flush_invalidate_region(p1addr, size);
  85                 break;
  86         case DMA_TO_DEVICE:             /* writeback only */
  87                 __flush_wback_region(p1addr, size);
  88                 break;
  89         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  90                 __flush_purge_region(p1addr, size);
  91                 break;
  92         default:
  93                 BUG();
  94         }
  95 }
  96 EXPORT_SYMBOL(dma_cache_sync);
  97
  98 static int __init memchunk_setup(char *str)
  99 {
 100         return 1; /* accept anything that begins with "memchunk." */
 101 }
 102 __setup("memchunk.", memchunk_setup);
 103
 104 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
 105 {
 106         char *p = boot_command_line;
 107         int k = strlen(name);
 108
 109         while ((p = strstr(p, "memchunk."))) {
 110                 p += 9; /* strlen("memchunk.") */
 111                 if (!strncmp(name, p, k) && p[k] == '=') {
 112                         p += k + 1;
 113                         *sizep = memparse(p, NULL);
 114                         pr_info("%s: forcing memory chunk size to 0x%08lx\n",
 115                                 name, *sizep);
 116                         break;
 117                 }
 118         }
 119 }
 120
 121 int __init platform_resource_setup_memory(struct platform_device *pdev,
 122                                           char *name, unsigned long memsize)
 123 {
 124         struct resource *r;
 125         dma_addr_t dma_handle;
 126         void *buf;
 127
 128         r = pdev->resource + pdev->num_resources - 1;
 129         if (r->flags) {
 130                 pr_warning("%s: unable to find empty space for resource\n",
 131                         name);
 132                 return -EINVAL;
 133         }
 134
 135         memchunk_cmdline_override(name, &memsize);
 136         if (!memsize)
 137                 return 0;
 138
 139         buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
 140         if (!buf) {
 141                 pr_warning("%s: unable to allocate memory\n", name);
 142                 return -ENOMEM;
 143         }
 144
 145         memset(buf, 0, memsize);
 146
 147         r->flags = IORESOURCE_MEM;
 148         r->start = dma_handle;
 149         r->end = r->start + memsize - 1;
 150         r->name = name;
 151         return 0;
 152 }