LXR linux/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
  23static int __init dma_init(void)
  24{
  25        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
  26        return 0;
  27}
  28fs_initcall(dma_init);
  29
  30void *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}
  64EXPORT_SYMBOL(dma_alloc_coherent);
  65
  66void 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}
  83EXPORT_SYMBOL(dma_free_coherent);
  84
  85void 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}
 108EXPORT_SYMBOL(dma_cache_sync);
 109
 110static int __init memchunk_setup(char *str)
 111{
 112        return 1; /* accept anything that begins with "memchunk." */
 113}
 114__setup("memchunk.", memchunk_setup);
 115
 116static 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
 133int __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}
 165