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