1/* Glue code to lib/swiotlb.c */
  2
  3#include <linux/pci.h>
  4#include <linux/cache.h>
  5#include <linux/init.h>
  6#include <linux/swiotlb.h>
  7#include <linux/bootmem.h>
  8#include <linux/dma-mapping.h>
  9
 10#include <asm/iommu.h>
 11#include <asm/swiotlb.h>
 12#include <asm/dma.h>
 13#include <asm/xen/swiotlb-xen.h>
 14#include <asm/iommu_table.h>
 15int swiotlb __read_mostly;
 16
 17void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 18					dma_addr_t *dma_handle, gfp_t flags,
 19					unsigned long attrs)
 20{
 21	void *vaddr;
 22
 23	/*
 24	 * Don't print a warning when the first allocation attempt fails.
 25	 * swiotlb_alloc_coherent() will print a warning when the DMA
 26	 * memory allocation ultimately failed.
 27	 */
 28	flags |= __GFP_NOWARN;
 29
 30	vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
 31					   attrs);
 32	if (vaddr)
 33		return vaddr;
 34
 35	return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
 36}
 37
 38void x86_swiotlb_free_coherent(struct device *dev, size_t size,
 39				      void *vaddr, dma_addr_t dma_addr,
 40				      unsigned long attrs)
 41{
 42	if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
 43		swiotlb_free_coherent(dev, size, vaddr, dma_addr);
 44	else
 45		dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
 46}
 47
 48static struct dma_map_ops swiotlb_dma_ops = {
 49	.mapping_error = swiotlb_dma_mapping_error,
 50	.alloc = x86_swiotlb_alloc_coherent,
 51	.free = x86_swiotlb_free_coherent,
 52	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
 53	.sync_single_for_device = swiotlb_sync_single_for_device,
 54	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
 55	.sync_sg_for_device = swiotlb_sync_sg_for_device,
 56	.map_sg = swiotlb_map_sg_attrs,
 57	.unmap_sg = swiotlb_unmap_sg_attrs,
 58	.map_page = swiotlb_map_page,
 59	.unmap_page = swiotlb_unmap_page,
 60	.dma_supported = NULL,
 61};
 62
 63/*
 64 * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
 65 *
 66 * This returns non-zero if we are forced to use swiotlb (by the boot
 67 * option).
 68 */
 69int __init pci_swiotlb_detect_override(void)
 70{
 71	if (swiotlb_force == SWIOTLB_FORCE)
 72		swiotlb = 1;
 73
 74	return swiotlb;
 75}
 76IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
 77		  pci_xen_swiotlb_detect,
 78		  pci_swiotlb_init,
 79		  pci_swiotlb_late_init);
 80
 81/*
 82 * if 4GB or more detected (and iommu=off not set) return 1
 83 * and set swiotlb to 1.
 84 */
 85int __init pci_swiotlb_detect_4gb(void)
 86{
 87	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
 88#ifdef CONFIG_X86_64
 89	if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
 90		swiotlb = 1;
 91#endif
 92	return swiotlb;
 93}
 94IOMMU_INIT(pci_swiotlb_detect_4gb,
 95	   pci_swiotlb_detect_override,
 96	   pci_swiotlb_init,
 97	   pci_swiotlb_late_init);
 98
 99void __init pci_swiotlb_init(void)
100{
101	if (swiotlb) {
102		swiotlb_init(0);
103		dma_ops = &swiotlb_dma_ops;
104	}
105}
106
107void __init pci_swiotlb_late_init(void)
108{
109	/* An IOMMU turned us off. */
110	if (!swiotlb)
111		swiotlb_free();
112	else {
113		printk(KERN_INFO "PCI-DMA: "
114		       "Using software bounce buffering for IO (SWIOTLB)\n");
115		swiotlb_print_info();
116	}
117}