arch/xtensa/kernel/pci-dma.c

   1 /*
   2  * arch/xtensa/kernel/pci-dma.c
   3  *
   4  * DMA coherent memory allocation.
   5  *
   6  * This program is free software; you can redistribute  it and/or modify it
   7  * under  the terms of  the GNU General  Public License as published by the
   8  * Free Software Foundation;  either version 2 of the  License, or (at your
   9  * option) any later version.
  10  *
  11  * Copyright (C) 2002 - 2005 Tensilica Inc.
  12  *
  13  * Based on version for i386.
  14  *
  15  * Chris Zankel <chris@zankel.net>
  16  * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
  17  */
  18
  19 #include <linux/types.h>
  20 #include <linux/mm.h>
  21 #include <linux/string.h>
  22 #include <linux/pci.h>
  23 #include <asm/io.h>
  24 #include <asm/cacheflush.h>
  25
  26 /*
  27  * Note: We assume that the full memory space is always mapped to 'kseg'
  28  *       Otherwise we have to use page attributes (not implemented).
  29  */
  30
  31 void *
  32 dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
  33 {
  34         void *ret;
  35
  36         /* ignore region speicifiers */
  37         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  38
  39         if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  40                 gfp |= GFP_DMA;
  41         ret = (void *)__get_free_pages(gfp, get_order(size));
  42
  43         if (ret != NULL) {
  44                 memset(ret, 0, size);
  45                 *handle = virt_to_bus(ret);
  46         }
  47         return (void*) BYPASS_ADDR((unsigned long)ret);
  48 }
  49
  50 void dma_free_coherent(struct device *hwdev, size_t size,
  51                          void *vaddr, dma_addr_t dma_handle)
  52 {
  53         free_pages(CACHED_ADDR((unsigned long)vaddr), get_order(size));
  54 }
  55
  56
  57 void consistent_sync(void *vaddr, size_t size, int direction)
  58 {
  59         switch (direction) {
  60         case PCI_DMA_NONE:
  61                 BUG();
  62         case PCI_DMA_FROMDEVICE:        /* invalidate only */
  63                 __invalidate_dcache_range((unsigned long)vaddr,
  64                                           (unsigned long)size);
  65                 break;
  66
  67         case PCI_DMA_TODEVICE:          /* writeback only */
  68         case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */
  69                 __flush_invalidate_dcache_range((unsigned long)vaddr,
  70                                                 (unsigned long)size);
  71                 break;
  72         }
  73 }