LXR linux/arch/mn10300/mm/dma-alloc.c

   1/* MN10300 Dynamic DMA mapping support
   2 *
   3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 * Derived from: arch/i386/kernel/pci-dma.c
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public Licence
   9 * as published by the Free Software Foundation; either version
  10 * 2 of the Licence, or (at your option) any later version.
  11 */
  12
  13#include <linux/types.h>
  14#include <linux/mm.h>
  15#include <linux/string.h>
  16#include <linux/pci.h>
  17#include <linux/gfp.h>
  18#include <linux/export.h>
  19#include <asm/io.h>
  20
  21static unsigned long pci_sram_allocated = 0xbc000000;
  22
  23void *dma_alloc_coherent(struct device *dev, size_t size,
  24                         dma_addr_t *dma_handle, int gfp)
  25{
  26        unsigned long addr;
  27        void *ret;
  28
  29        pr_debug("dma_alloc_coherent(%s,%zu,%x)\n",
  30                 dev ? dev_name(dev) : "?", size, gfp);
  31
  32        if (0xbe000000 - pci_sram_allocated >= size) {
  33                size = (size + 255) & ~255;
  34                addr = pci_sram_allocated;
  35                pci_sram_allocated += size;
  36                ret = (void *) addr;
  37                goto done;
  38        }
  39
  40        /* ignore region specifiers */
  41        gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  42
  43        if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
  44                gfp |= GFP_DMA;
  45
  46        addr = __get_free_pages(gfp, get_order(size));
  47        if (!addr)
  48                return NULL;
  49
  50        /* map the coherent memory through the uncached memory window */
  51        ret = (void *) (addr | 0x20000000);
  52
  53        /* fill the memory with obvious rubbish */
  54        memset((void *) addr, 0xfb, size);
  55
  56        /* write back and evict all cache lines covering this region */
  57        mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
  58
  59done:
  60        *dma_handle = virt_to_bus((void *) addr);
  61        printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle);
  62        return ret;
  63}
  64EXPORT_SYMBOL(dma_alloc_coherent);
  65
  66void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
  67                       dma_addr_t dma_handle)
  68{
  69        unsigned long addr = (unsigned long) vaddr & ~0x20000000;
  70
  71        if (addr >= 0x9c000000)
  72                return;
  73
  74        free_pages(addr, get_order(size));
  75}
  76EXPORT_SYMBOL(dma_free_coherent);
  77