arch/x86_64/kernel/pci-nommu.c

   1 /* Fallback functions when the main IOMMU code is not compiled in. This
   2    code is roughly equivalent to i386. */
   3 #include <linux/mm.h>
   4 #include <linux/init.h>
   5 #include <linux/pci.h>
   6 #include <linux/string.h>
   7 #include <asm/proto.h>
   8 #include <asm/processor.h>
   9
  10 int iommu_merge = 0;
  11 EXPORT_SYMBOL(iommu_merge);
  12
  13 dma_addr_t bad_dma_address;
  14 EXPORT_SYMBOL(bad_dma_address);
  15
  16 int iommu_bio_merge = 0;
  17 EXPORT_SYMBOL(iommu_bio_merge);
  18
  19 int iommu_sac_force = 0;
  20 EXPORT_SYMBOL(iommu_sac_force);
  21
  22 /*
  23  * Dummy IO MMU functions
  24  */
  25
  26 void *dma_alloc_coherent(struct device *hwdev, size_t size,
  27                          dma_addr_t *dma_handle, unsigned gfp)
  28 {
  29         void *ret;
  30         u64 mask;
  31         int order = get_order(size);
  32
  33         if (hwdev)
  34                 mask = hwdev->coherent_dma_mask & *hwdev->dma_mask;
  35         else
  36                 mask = 0xffffffff;
  37         for (;;) {
  38                 ret = (void *)__get_free_pages(gfp, order);
  39                 if (ret == NULL)
  40                         return NULL;
  41                 *dma_handle = virt_to_bus(ret);
  42                 if ((*dma_handle & ~mask) == 0)
  43                         break;
  44                 free_pages((unsigned long)ret, order);
  45                 if (gfp & GFP_DMA)
  46                         return NULL;
  47                 gfp |= GFP_DMA;
  48         }
  49
  50         memset(ret, 0, size);
  51         return ret;
  52 }
  53 EXPORT_SYMBOL(dma_alloc_coherent);
  54
  55 void dma_free_coherent(struct device *hwdev, size_t size,
  56                          void *vaddr, dma_addr_t dma_handle)
  57 {
  58         free_pages((unsigned long)vaddr, get_order(size));
  59 }
  60 EXPORT_SYMBOL(dma_free_coherent);
  61
  62 int dma_supported(struct device *hwdev, u64 mask)
  63 {
  64         /*
  65          * we fall back to GFP_DMA when the mask isn't all 1s,
  66          * so we can't guarantee allocations that must be
  67          * within a tighter range than GFP_DMA..
  68          * RED-PEN this won't work for pci_map_single. Caller has to
  69          * use GFP_DMA in the first place.
  70          */
  71         if (mask < 0x00ffffff)
  72                 return 0;
  73
  74         return 1;
  75 }
  76 EXPORT_SYMBOL(dma_supported);
  77
  78 int dma_get_cache_alignment(void)
  79 {
  80         return boot_cpu_data.x86_clflush_size;
  81 }
  82 EXPORT_SYMBOL(dma_get_cache_alignment);
  83
  84 static int __init check_ram(void)
  85 {
  86         if (end_pfn >= 0xffffffff>>PAGE_SHIFT) {
  87                 printk(
  88                 KERN_ERR "WARNING more than 4GB of memory but IOMMU not compiled in.\n"
  89                 KERN_ERR "WARNING 32bit PCI may malfunction.\n");
  90         }
  91         return 0;
  92 }
  93 __initcall(check_ram);
  94