arch/x86_64/kernel/pci-nommu.c

   1 #include <linux/mm.h>
   2 #include <linux/init.h>
   3 #include <linux/pci.h>
   4 #include <linux/string.h>
   5
   6 /*
   7  * Dummy IO MMU functions
   8  */
   9
  10 extern unsigned long end_pfn;
  11
  12 void *pci_alloc_consistent(struct pci_dev *hwdev, size_t size,
  13                            dma_addr_t *dma_handle)
  14 {
  15         void *ret;
  16         int gfp = GFP_ATOMIC;
  17
  18         if (hwdev == NULL ||
  19             end_pfn > (hwdev->dma_mask>>PAGE_SHIFT) ||  /* XXX */
  20             (u32)hwdev->dma_mask < 0xffffffff)
  21                 gfp |= GFP_DMA;
  22         ret = (void *)__get_free_pages(gfp, get_order(size));
  23
  24         if (ret != NULL) {
  25                 memset(ret, 0, size);
  26                 *dma_handle = virt_to_bus(ret);
  27         }
  28         return ret;
  29 }
  30
  31 void pci_free_consistent(struct pci_dev *hwdev, size_t size,
  32                          void *vaddr, dma_addr_t dma_handle)
  33 {
  34         free_pages((unsigned long)vaddr, get_order(size));
  35 }
  36
  37
  38 static void __init check_ram(void)
  39 {
  40         if (end_pfn >= 0xffffffff>>PAGE_SHIFT) {
  41                 printk(KERN_ERR "WARNING more than 4GB of memory but no IOMMU.\n"
  42                        KERN_ERR "WARNING 32bit PCI may malfunction.\n");
  43                 /* Could play with highmem_start_page here to trick some subsystems
  44                    into bounce buffers. Unfortunately that would require setting
  45                    CONFIG_HIGHMEM too.
  46                  */
  47         }
  48 }