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consistent.c

/*
 * arch/sh/mm/consistent.c
 *
 * Copyright (C) 2004 - 2007  Paul Mundt
 *
 * Declared coherent memory functions based on arch/x86/kernel/pci-dma_32.c
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/mm.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <asm/cacheflush.h>
#include <asm/addrspace.h>
#include <asm/io.h>

struct dma_coherent_mem {
      void        *virt_base;
      u32         device_base;
      int         size;
      int         flags;
      unsigned long     *bitmap;
};

void *dma_alloc_coherent(struct device *dev, size_t size,
                     dma_addr_t *dma_handle, gfp_t gfp)
{
      void *ret, *ret_nocache;
      int order = get_order(size);

      if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
            return ret;

      ret = (void *)__get_free_pages(gfp, order);
      if (!ret)
            return NULL;

      memset(ret, 0, size);
      /*
       * Pages from the page allocator may have data present in
       * cache. So flush the cache before using uncached memory.
       */
      dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);

      ret_nocache = ioremap_nocache(virt_to_phys(ret), size);
      if (!ret_nocache) {
            free_pages((unsigned long)ret, order);
            return NULL;
      }

      *dma_handle = virt_to_phys(ret);
      return ret_nocache;
}
EXPORT_SYMBOL(dma_alloc_coherent);

void dma_free_coherent(struct device *dev, size_t size,
                   void *vaddr, dma_addr_t dma_handle)
{
      struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
      int order = get_order(size);

      if (!dma_release_from_coherent(dev, order, vaddr)) {
            WARN_ON(irqs_disabled());     /* for portability */
            BUG_ON(mem && mem->flags & DMA_MEMORY_EXCLUSIVE);
            free_pages((unsigned long)phys_to_virt(dma_handle), order);
            iounmap(vaddr);
      }
}
EXPORT_SYMBOL(dma_free_coherent);

void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
                enum dma_data_direction direction)
{
#ifdef CONFIG_CPU_SH5
      void *p1addr = vaddr;
#else
      void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
#endif

      switch (direction) {
      case DMA_FROM_DEVICE:         /* invalidate only */
            __flush_invalidate_region(p1addr, size);
            break;
      case DMA_TO_DEVICE:           /* writeback only */
            __flush_wback_region(p1addr, size);
            break;
      case DMA_BIDIRECTIONAL:       /* writeback and invalidate */
            __flush_purge_region(p1addr, size);
            break;
      default:
            BUG();
      }
}
EXPORT_SYMBOL(dma_cache_sync);

static int __init memchunk_setup(char *str)
{
      return 1; /* accept anything that begins with "memchunk." */
}
__setup("memchunk.", memchunk_setup);

static void memchunk_cmdline_override(char *name, unsigned long *sizep)
{
      char *p = boot_command_line;
      int k = strlen(name);

      while ((p = strstr(p, "memchunk."))) {
            p += 9; /* strlen("memchunk.") */
            if (!strncmp(name, p, k) && p[k] == '=') {
                  p += k + 1;
                  *sizep = memparse(p, NULL);
                  pr_info("%s: forcing memory chunk size to 0x%08lx\n",
                        name, *sizep);
                  break;
            }
      }
}

int platform_resource_setup_memory(struct platform_device *pdev,
                           char *name, unsigned long memsize)
{
      struct resource *r;
      dma_addr_t dma_handle;
      void *buf;

      r = pdev->resource + pdev->num_resources - 1;
      if (r->flags) {
            pr_warning("%s: unable to find empty space for resource\n",
                  name);
            return -EINVAL;
      }

      memchunk_cmdline_override(name, &memsize);
      if (!memsize)
            return 0;

      buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
      if (!buf) {
            pr_warning("%s: unable to allocate memory\n", name);
            return -ENOMEM;
      }

      memset(buf, 0, memsize);

      r->flags = IORESOURCE_MEM;
      r->start = dma_handle;
      r->end = r->start + memsize - 1;
      r->name = name;
      return 0;
}

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