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 <linux/gfp.h>
  24 #include <linux/module.h>
  25 #include <asm/io.h>
  26 #include <asm/cacheflush.h>
  27
  28 /*
  29  * Note: We assume that the full memory space is always mapped to 'kseg'
  30  *       Otherwise we have to use page attributes (not implemented).
  31  */
  32
  33 void *
  34 dma_alloc_coherent(struct device *dev,size_t size,dma_addr_t *handle,gfp_t flag)
  35 {
  36         unsigned long ret;
  37         unsigned long uncached = 0;
  38
  39         /* ignore region speicifiers */
  40
  41         flag &= ~(__GFP_DMA | __GFP_HIGHMEM);
  42
  43         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
  44                 flag |= GFP_DMA;
  45         ret = (unsigned long)__get_free_pages(flag, get_order(size));
  46
  47         if (ret == 0)
  48                 return NULL;
  49
  50         /* We currently don't support coherent memory outside KSEG */
  51
  52         BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
  53                ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
  54
  55
  56         if (ret != 0) {
  57                 memset((void*) ret, 0, size);
  58                 uncached = ret+XCHAL_KSEG_BYPASS_VADDR-XCHAL_KSEG_CACHED_VADDR;
  59                 *handle = virt_to_bus((void*)ret);
  60                 __flush_invalidate_dcache_range(ret, size);
  61         }
  62
  63         return (void*)uncached;
  64 }
  65 EXPORT_SYMBOL(dma_alloc_coherent);
  66
  67 void dma_free_coherent(struct device *hwdev, size_t size,
  68                          void *vaddr, dma_addr_t dma_handle)
  69 {
  70         unsigned long addr = (unsigned long)vaddr +
  71                 XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
  72
  73         BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
  74                addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
  75
  76         free_pages(addr, get_order(size));
  77 }
  78 EXPORT_SYMBOL(dma_free_coherent);
  79
  80
  81 void consistent_sync(void *vaddr, size_t size, int direction)
  82 {
  83         switch (direction) {
  84         case PCI_DMA_NONE:
  85                 BUG();
  86         case PCI_DMA_FROMDEVICE:        /* invalidate only */
  87                 __invalidate_dcache_range((unsigned long)vaddr,
  88                                           (unsigned long)size);
  89                 break;
  90
  91         case PCI_DMA_TODEVICE:          /* writeback only */
  92         case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */
  93                 __flush_invalidate_dcache_range((unsigned long)vaddr,
  94                                                 (unsigned long)size);
  95                 break;
  96         }
  97 }
  98 EXPORT_SYMBOL(consistent_sync);