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 <asm/io.h>
  19
  20 static unsigned long pci_sram_allocated = 0xbc000000;
  21
  22 void *dma_alloc_coherent(struct device *dev, size_t size,
  23                          dma_addr_t *dma_handle, int gfp)
  24 {
  25         unsigned long addr;
  26         void *ret;
  27
  28         pr_debug("dma_alloc_coherent(%s,%zu,%x)\n",
  29                  dev ? dev_name(dev) : "?", size, gfp);
  30
  31         if (0xbe000000 - pci_sram_allocated >= size) {
  32                 size = (size + 255) & ~255;
  33                 addr = pci_sram_allocated;
  34                 pci_sram_allocated += size;
  35                 ret = (void *) addr;
  36                 goto done;
  37         }
  38
  39         /* ignore region specifiers */
  40         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  41
  42         if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
  43                 gfp |= GFP_DMA;
  44
  45         addr = __get_free_pages(gfp, get_order(size));
  46         if (!addr)
  47                 return NULL;
  48
  49         /* map the coherent memory through the uncached memory window */
  50         ret = (void *) (addr | 0x20000000);
  51
  52         /* fill the memory with obvious rubbish */
  53         memset((void *) addr, 0xfb, size);
  54
  55         /* write back and evict all cache lines covering this region */
  56         mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
  57
  58 done:
  59         *dma_handle = virt_to_bus((void *) addr);
  60         printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle);
  61         return ret;
  62 }
  63 EXPORT_SYMBOL(dma_alloc_coherent);
  64
  65 void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
  66                        dma_addr_t dma_handle)
  67 {
  68         unsigned long addr = (unsigned long) vaddr & ~0x20000000;
  69
  70         if (addr >= 0x9c000000)
  71                 return;
  72
  73         free_pages(addr, get_order(size));
  74 }
  75 EXPORT_SYMBOL(dma_free_coherent);