Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / arch / x86 / kernel / amd_gart_64.c
diff --git a/kernel/arch/x86/kernel/amd_gart_64.c b/kernel/arch/x86/kernel/amd_gart_64.c
new file mode 100644 (file)
index 0000000..8e3842f
--- /dev/null
@@ -0,0 +1,898 @@
+/*
+ * Dynamic DMA mapping support for AMD Hammer.
+ *
+ * Use the integrated AGP GART in the Hammer northbridge as an IOMMU for PCI.
+ * This allows to use PCI devices that only support 32bit addresses on systems
+ * with more than 4GB.
+ *
+ * See Documentation/DMA-API-HOWTO.txt for the interface specification.
+ *
+ * Copyright 2002 Andi Kleen, SuSE Labs.
+ * Subject to the GNU General Public License v2 only.
+ */
+
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/agp_backend.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/pci.h>
+#include <linux/module.h>
+#include <linux/topology.h>
+#include <linux/interrupt.h>
+#include <linux/bitmap.h>
+#include <linux/kdebug.h>
+#include <linux/scatterlist.h>
+#include <linux/iommu-helper.h>
+#include <linux/syscore_ops.h>
+#include <linux/io.h>
+#include <linux/gfp.h>
+#include <linux/atomic.h>
+#include <asm/mtrr.h>
+#include <asm/pgtable.h>
+#include <asm/proto.h>
+#include <asm/iommu.h>
+#include <asm/gart.h>
+#include <asm/cacheflush.h>
+#include <asm/swiotlb.h>
+#include <asm/dma.h>
+#include <asm/amd_nb.h>
+#include <asm/x86_init.h>
+#include <asm/iommu_table.h>
+
+static unsigned long iommu_bus_base;   /* GART remapping area (physical) */
+static unsigned long iommu_size;       /* size of remapping area bytes */
+static unsigned long iommu_pages;      /* .. and in pages */
+
+static u32 *iommu_gatt_base;           /* Remapping table */
+
+static dma_addr_t bad_dma_addr;
+
+/*
+ * If this is disabled the IOMMU will use an optimized flushing strategy
+ * of only flushing when an mapping is reused. With it true the GART is
+ * flushed for every mapping. Problem is that doing the lazy flush seems
+ * to trigger bugs with some popular PCI cards, in particular 3ware (but
+ * has been also also seen with Qlogic at least).
+ */
+static int iommu_fullflush = 1;
+
+/* Allocation bitmap for the remapping area: */
+static DEFINE_SPINLOCK(iommu_bitmap_lock);
+/* Guarded by iommu_bitmap_lock: */
+static unsigned long *iommu_gart_bitmap;
+
+static u32 gart_unmapped_entry;
+
+#define GPTE_VALID    1
+#define GPTE_COHERENT 2
+#define GPTE_ENCODE(x) \
+       (((x) & 0xfffff000) | (((x) >> 32) << 4) | GPTE_VALID | GPTE_COHERENT)
+#define GPTE_DECODE(x) (((x) & 0xfffff000) | (((u64)(x) & 0xff0) << 28))
+
+#define EMERGENCY_PAGES 32 /* = 128KB */
+
+#ifdef CONFIG_AGP
+#define AGPEXTERN extern
+#else
+#define AGPEXTERN
+#endif
+
+/* GART can only remap to physical addresses < 1TB */
+#define GART_MAX_PHYS_ADDR     (1ULL << 40)
+
+/* backdoor interface to AGP driver */
+AGPEXTERN int agp_memory_reserved;
+AGPEXTERN __u32 *agp_gatt_table;
+
+static unsigned long next_bit;  /* protected by iommu_bitmap_lock */
+static bool need_flush;                /* global flush state. set for each gart wrap */
+
+static unsigned long alloc_iommu(struct device *dev, int size,
+                                unsigned long align_mask)
+{
+       unsigned long offset, flags;
+       unsigned long boundary_size;
+       unsigned long base_index;
+
+       base_index = ALIGN(iommu_bus_base & dma_get_seg_boundary(dev),
+                          PAGE_SIZE) >> PAGE_SHIFT;
+       boundary_size = ALIGN((u64)dma_get_seg_boundary(dev) + 1,
+                             PAGE_SIZE) >> PAGE_SHIFT;
+
+       spin_lock_irqsave(&iommu_bitmap_lock, flags);
+       offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, next_bit,
+                                 size, base_index, boundary_size, align_mask);
+       if (offset == -1) {
+               need_flush = true;
+               offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, 0,
+                                         size, base_index, boundary_size,
+                                         align_mask);
+       }
+       if (offset != -1) {
+               next_bit = offset+size;
+               if (next_bit >= iommu_pages) {
+                       next_bit = 0;
+                       need_flush = true;
+               }
+       }
+       if (iommu_fullflush)
+               need_flush = true;
+       spin_unlock_irqrestore(&iommu_bitmap_lock, flags);
+
+       return offset;
+}
+
+static void free_iommu(unsigned long offset, int size)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&iommu_bitmap_lock, flags);
+       bitmap_clear(iommu_gart_bitmap, offset, size);
+       if (offset >= next_bit)
+               next_bit = offset + size;
+       spin_unlock_irqrestore(&iommu_bitmap_lock, flags);
+}
+
+/*
+ * Use global flush state to avoid races with multiple flushers.
+ */
+static void flush_gart(void)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&iommu_bitmap_lock, flags);
+       if (need_flush) {
+               amd_flush_garts();
+               need_flush = false;
+       }
+       spin_unlock_irqrestore(&iommu_bitmap_lock, flags);
+}
+
+#ifdef CONFIG_IOMMU_LEAK
+/* Debugging aid for drivers that don't free their IOMMU tables */
+static int leak_trace;
+static int iommu_leak_pages = 20;
+
+static void dump_leak(void)
+{
+       static int dump;
+
+       if (dump)
+               return;
+       dump = 1;
+
+       show_stack(NULL, NULL);
+       debug_dma_dump_mappings(NULL);
+}
+#endif
+
+static void iommu_full(struct device *dev, size_t size, int dir)
+{
+       /*
+        * Ran out of IOMMU space for this operation. This is very bad.
+        * Unfortunately the drivers cannot handle this operation properly.
+        * Return some non mapped prereserved space in the aperture and
+        * let the Northbridge deal with it. This will result in garbage
+        * in the IO operation. When the size exceeds the prereserved space
+        * memory corruption will occur or random memory will be DMAed
+        * out. Hopefully no network devices use single mappings that big.
+        */
+
+       dev_err(dev, "PCI-DMA: Out of IOMMU space for %lu bytes\n", size);
+
+       if (size > PAGE_SIZE*EMERGENCY_PAGES) {
+               if (dir == PCI_DMA_FROMDEVICE || dir == PCI_DMA_BIDIRECTIONAL)
+                       panic("PCI-DMA: Memory would be corrupted\n");
+               if (dir == PCI_DMA_TODEVICE || dir == PCI_DMA_BIDIRECTIONAL)
+                       panic(KERN_ERR
+                               "PCI-DMA: Random memory would be DMAed\n");
+       }
+#ifdef CONFIG_IOMMU_LEAK
+       dump_leak();
+#endif
+}
+
+static inline int
+need_iommu(struct device *dev, unsigned long addr, size_t size)
+{
+       return force_iommu || !dma_capable(dev, addr, size);
+}
+
+static inline int
+nonforced_iommu(struct device *dev, unsigned long addr, size_t size)
+{
+       return !dma_capable(dev, addr, size);
+}
+
+/* Map a single continuous physical area into the IOMMU.
+ * Caller needs to check if the iommu is needed and flush.
+ */
+static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
+                               size_t size, int dir, unsigned long align_mask)
+{
+       unsigned long npages = iommu_num_pages(phys_mem, size, PAGE_SIZE);
+       unsigned long iommu_page;
+       int i;
+
+       if (unlikely(phys_mem + size > GART_MAX_PHYS_ADDR))
+               return bad_dma_addr;
+
+       iommu_page = alloc_iommu(dev, npages, align_mask);
+       if (iommu_page == -1) {
+               if (!nonforced_iommu(dev, phys_mem, size))
+                       return phys_mem;
+               if (panic_on_overflow)
+                       panic("dma_map_area overflow %lu bytes\n", size);
+               iommu_full(dev, size, dir);
+               return bad_dma_addr;
+       }
+
+       for (i = 0; i < npages; i++) {
+               iommu_gatt_base[iommu_page + i] = GPTE_ENCODE(phys_mem);
+               phys_mem += PAGE_SIZE;
+       }
+       return iommu_bus_base + iommu_page*PAGE_SIZE + (phys_mem & ~PAGE_MASK);
+}
+
+/* Map a single area into the IOMMU */
+static dma_addr_t gart_map_page(struct device *dev, struct page *page,
+                               unsigned long offset, size_t size,
+                               enum dma_data_direction dir,
+                               struct dma_attrs *attrs)
+{
+       unsigned long bus;
+       phys_addr_t paddr = page_to_phys(page) + offset;
+
+       if (!dev)
+               dev = &x86_dma_fallback_dev;
+
+       if (!need_iommu(dev, paddr, size))
+               return paddr;
+
+       bus = dma_map_area(dev, paddr, size, dir, 0);
+       flush_gart();
+
+       return bus;
+}
+
+/*
+ * Free a DMA mapping.
+ */
+static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
+                           size_t size, enum dma_data_direction dir,
+                           struct dma_attrs *attrs)
+{
+       unsigned long iommu_page;
+       int npages;
+       int i;
+
+       if (dma_addr < iommu_bus_base + EMERGENCY_PAGES*PAGE_SIZE ||
+           dma_addr >= iommu_bus_base + iommu_size)
+               return;
+
+       iommu_page = (dma_addr - iommu_bus_base)>>PAGE_SHIFT;
+       npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
+       for (i = 0; i < npages; i++) {
+               iommu_gatt_base[iommu_page + i] = gart_unmapped_entry;
+       }
+       free_iommu(iommu_page, npages);
+}
+
+/*
+ * Wrapper for pci_unmap_single working with scatterlists.
+ */
+static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
+                         enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+       struct scatterlist *s;
+       int i;
+
+       for_each_sg(sg, s, nents, i) {
+               if (!s->dma_length || !s->length)
+                       break;
+               gart_unmap_page(dev, s->dma_address, s->dma_length, dir, NULL);
+       }
+}
+
+/* Fallback for dma_map_sg in case of overflow */
+static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
+                              int nents, int dir)
+{
+       struct scatterlist *s;
+       int i;
+
+#ifdef CONFIG_IOMMU_DEBUG
+       pr_debug("dma_map_sg overflow\n");
+#endif
+
+       for_each_sg(sg, s, nents, i) {
+               unsigned long addr = sg_phys(s);
+
+               if (nonforced_iommu(dev, addr, s->length)) {
+                       addr = dma_map_area(dev, addr, s->length, dir, 0);
+                       if (addr == bad_dma_addr) {
+                               if (i > 0)
+                                       gart_unmap_sg(dev, sg, i, dir, NULL);
+                               nents = 0;
+                               sg[0].dma_length = 0;
+                               break;
+                       }
+               }
+               s->dma_address = addr;
+               s->dma_length = s->length;
+       }
+       flush_gart();
+
+       return nents;
+}
+
+/* Map multiple scatterlist entries continuous into the first. */
+static int __dma_map_cont(struct device *dev, struct scatterlist *start,
+                         int nelems, struct scatterlist *sout,
+                         unsigned long pages)
+{
+       unsigned long iommu_start = alloc_iommu(dev, pages, 0);
+       unsigned long iommu_page = iommu_start;
+       struct scatterlist *s;
+       int i;
+
+       if (iommu_start == -1)
+               return -1;
+
+       for_each_sg(start, s, nelems, i) {
+               unsigned long pages, addr;
+               unsigned long phys_addr = s->dma_address;
+
+               BUG_ON(s != start && s->offset);
+               if (s == start) {
+                       sout->dma_address = iommu_bus_base;
+                       sout->dma_address += iommu_page*PAGE_SIZE + s->offset;
+                       sout->dma_length = s->length;
+               } else {
+                       sout->dma_length += s->length;
+               }
+
+               addr = phys_addr;
+               pages = iommu_num_pages(s->offset, s->length, PAGE_SIZE);
+               while (pages--) {
+                       iommu_gatt_base[iommu_page] = GPTE_ENCODE(addr);
+                       addr += PAGE_SIZE;
+                       iommu_page++;
+               }
+       }
+       BUG_ON(iommu_page - iommu_start != pages);
+
+       return 0;
+}
+
+static inline int
+dma_map_cont(struct device *dev, struct scatterlist *start, int nelems,
+            struct scatterlist *sout, unsigned long pages, int need)
+{
+       if (!need) {
+               BUG_ON(nelems != 1);
+               sout->dma_address = start->dma_address;
+               sout->dma_length = start->length;
+               return 0;
+       }
+       return __dma_map_cont(dev, start, nelems, sout, pages);
+}
+
+/*
+ * DMA map all entries in a scatterlist.
+ * Merge chunks that have page aligned sizes into a continuous mapping.
+ */
+static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+                      enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+       struct scatterlist *s, *ps, *start_sg, *sgmap;
+       int need = 0, nextneed, i, out, start;
+       unsigned long pages = 0;
+       unsigned int seg_size;
+       unsigned int max_seg_size;
+
+       if (nents == 0)
+               return 0;
+
+       if (!dev)
+               dev = &x86_dma_fallback_dev;
+
+       out             = 0;
+       start           = 0;
+       start_sg        = sg;
+       sgmap           = sg;
+       seg_size        = 0;
+       max_seg_size    = dma_get_max_seg_size(dev);
+       ps              = NULL; /* shut up gcc */
+
+       for_each_sg(sg, s, nents, i) {
+               dma_addr_t addr = sg_phys(s);
+
+               s->dma_address = addr;
+               BUG_ON(s->length == 0);
+
+               nextneed = need_iommu(dev, addr, s->length);
+
+               /* Handle the previous not yet processed entries */
+               if (i > start) {
+                       /*
+                        * Can only merge when the last chunk ends on a
+                        * page boundary and the new one doesn't have an
+                        * offset.
+                        */
+                       if (!iommu_merge || !nextneed || !need || s->offset ||
+                           (s->length + seg_size > max_seg_size) ||
+                           (ps->offset + ps->length) % PAGE_SIZE) {
+                               if (dma_map_cont(dev, start_sg, i - start,
+                                                sgmap, pages, need) < 0)
+                                       goto error;
+                               out++;
+
+                               seg_size        = 0;
+                               sgmap           = sg_next(sgmap);
+                               pages           = 0;
+                               start           = i;
+                               start_sg        = s;
+                       }
+               }
+
+               seg_size += s->length;
+               need = nextneed;
+               pages += iommu_num_pages(s->offset, s->length, PAGE_SIZE);
+               ps = s;
+       }
+       if (dma_map_cont(dev, start_sg, i - start, sgmap, pages, need) < 0)
+               goto error;
+       out++;
+       flush_gart();
+       if (out < nents) {
+               sgmap = sg_next(sgmap);
+               sgmap->dma_length = 0;
+       }
+       return out;
+
+error:
+       flush_gart();
+       gart_unmap_sg(dev, sg, out, dir, NULL);
+
+       /* When it was forced or merged try again in a dumb way */
+       if (force_iommu || iommu_merge) {
+               out = dma_map_sg_nonforce(dev, sg, nents, dir);
+               if (out > 0)
+                       return out;
+       }
+       if (panic_on_overflow)
+               panic("dma_map_sg: overflow on %lu pages\n", pages);
+
+       iommu_full(dev, pages << PAGE_SHIFT, dir);
+       for_each_sg(sg, s, nents, i)
+               s->dma_address = bad_dma_addr;
+       return 0;
+}
+
+/* allocate and map a coherent mapping */
+static void *
+gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
+                   gfp_t flag, struct dma_attrs *attrs)
+{
+       dma_addr_t paddr;
+       unsigned long align_mask;
+       struct page *page;
+
+       if (force_iommu && !(flag & GFP_DMA)) {
+               flag &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
+               page = alloc_pages(flag | __GFP_ZERO, get_order(size));
+               if (!page)
+                       return NULL;
+
+               align_mask = (1UL << get_order(size)) - 1;
+               paddr = dma_map_area(dev, page_to_phys(page), size,
+                                    DMA_BIDIRECTIONAL, align_mask);
+
+               flush_gart();
+               if (paddr != bad_dma_addr) {
+                       *dma_addr = paddr;
+                       return page_address(page);
+               }
+               __free_pages(page, get_order(size));
+       } else
+               return dma_generic_alloc_coherent(dev, size, dma_addr, flag,
+                                                 attrs);
+
+       return NULL;
+}
+
+/* free a coherent mapping */
+static void
+gart_free_coherent(struct device *dev, size_t size, void *vaddr,
+                  dma_addr_t dma_addr, struct dma_attrs *attrs)
+{
+       gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, NULL);
+       dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
+}
+
+static int gart_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+       return (dma_addr == bad_dma_addr);
+}
+
+static int no_agp;
+
+static __init unsigned long check_iommu_size(unsigned long aper, u64 aper_size)
+{
+       unsigned long a;
+
+       if (!iommu_size) {
+               iommu_size = aper_size;
+               if (!no_agp)
+                       iommu_size /= 2;
+       }
+
+       a = aper + iommu_size;
+       iommu_size -= round_up(a, PMD_PAGE_SIZE) - a;
+
+       if (iommu_size < 64*1024*1024) {
+               pr_warning(
+                       "PCI-DMA: Warning: Small IOMMU %luMB."
+                       " Consider increasing the AGP aperture in BIOS\n",
+                               iommu_size >> 20);
+       }
+
+       return iommu_size;
+}
+
+static __init unsigned read_aperture(struct pci_dev *dev, u32 *size)
+{
+       unsigned aper_size = 0, aper_base_32, aper_order;
+       u64 aper_base;
+
+       pci_read_config_dword(dev, AMD64_GARTAPERTUREBASE, &aper_base_32);
+       pci_read_config_dword(dev, AMD64_GARTAPERTURECTL, &aper_order);
+       aper_order = (aper_order >> 1) & 7;
+
+       aper_base = aper_base_32 & 0x7fff;
+       aper_base <<= 25;
+
+       aper_size = (32 * 1024 * 1024) << aper_order;
+       if (aper_base + aper_size > 0x100000000UL || !aper_size)
+               aper_base = 0;
+
+       *size = aper_size;
+       return aper_base;
+}
+
+static void enable_gart_translations(void)
+{
+       int i;
+
+       if (!amd_nb_has_feature(AMD_NB_GART))
+               return;
+
+       for (i = 0; i < amd_nb_num(); i++) {
+               struct pci_dev *dev = node_to_amd_nb(i)->misc;
+
+               enable_gart_translation(dev, __pa(agp_gatt_table));
+       }
+
+       /* Flush the GART-TLB to remove stale entries */
+       amd_flush_garts();
+}
+
+/*
+ * If fix_up_north_bridges is set, the north bridges have to be fixed up on
+ * resume in the same way as they are handled in gart_iommu_hole_init().
+ */
+static bool fix_up_north_bridges;
+static u32 aperture_order;
+static u32 aperture_alloc;
+
+void set_up_gart_resume(u32 aper_order, u32 aper_alloc)
+{
+       fix_up_north_bridges = true;
+       aperture_order = aper_order;
+       aperture_alloc = aper_alloc;
+}
+
+static void gart_fixup_northbridges(void)
+{
+       int i;
+
+       if (!fix_up_north_bridges)
+               return;
+
+       if (!amd_nb_has_feature(AMD_NB_GART))
+               return;
+
+       pr_info("PCI-DMA: Restoring GART aperture settings\n");
+
+       for (i = 0; i < amd_nb_num(); i++) {
+               struct pci_dev *dev = node_to_amd_nb(i)->misc;
+
+               /*
+                * Don't enable translations just yet.  That is the next
+                * step.  Restore the pre-suspend aperture settings.
+                */
+               gart_set_size_and_enable(dev, aperture_order);
+               pci_write_config_dword(dev, AMD64_GARTAPERTUREBASE, aperture_alloc >> 25);
+       }
+}
+
+static void gart_resume(void)
+{
+       pr_info("PCI-DMA: Resuming GART IOMMU\n");
+
+       gart_fixup_northbridges();
+
+       enable_gart_translations();
+}
+
+static struct syscore_ops gart_syscore_ops = {
+       .resume         = gart_resume,
+
+};
+
+/*
+ * Private Northbridge GATT initialization in case we cannot use the
+ * AGP driver for some reason.
+ */
+static __init int init_amd_gatt(struct agp_kern_info *info)
+{
+       unsigned aper_size, gatt_size, new_aper_size;
+       unsigned aper_base, new_aper_base;
+       struct pci_dev *dev;
+       void *gatt;
+       int i;
+
+       pr_info("PCI-DMA: Disabling AGP.\n");
+
+       aper_size = aper_base = info->aper_size = 0;
+       dev = NULL;
+       for (i = 0; i < amd_nb_num(); i++) {
+               dev = node_to_amd_nb(i)->misc;
+               new_aper_base = read_aperture(dev, &new_aper_size);
+               if (!new_aper_base)
+                       goto nommu;
+
+               if (!aper_base) {
+                       aper_size = new_aper_size;
+                       aper_base = new_aper_base;
+               }
+               if (aper_size != new_aper_size || aper_base != new_aper_base)
+                       goto nommu;
+       }
+       if (!aper_base)
+               goto nommu;
+
+       info->aper_base = aper_base;
+       info->aper_size = aper_size >> 20;
+
+       gatt_size = (aper_size >> PAGE_SHIFT) * sizeof(u32);
+       gatt = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+                                       get_order(gatt_size));
+       if (!gatt)
+               panic("Cannot allocate GATT table");
+       if (set_memory_uc((unsigned long)gatt, gatt_size >> PAGE_SHIFT))
+               panic("Could not set GART PTEs to uncacheable pages");
+
+       agp_gatt_table = gatt;
+
+       register_syscore_ops(&gart_syscore_ops);
+
+       flush_gart();
+
+       pr_info("PCI-DMA: aperture base @ %x size %u KB\n",
+              aper_base, aper_size>>10);
+
+       return 0;
+
+ nommu:
+       /* Should not happen anymore */
+       pr_warning("PCI-DMA: More than 4GB of RAM and no IOMMU\n"
+              "falling back to iommu=soft.\n");
+       return -1;
+}
+
+static struct dma_map_ops gart_dma_ops = {
+       .map_sg                         = gart_map_sg,
+       .unmap_sg                       = gart_unmap_sg,
+       .map_page                       = gart_map_page,
+       .unmap_page                     = gart_unmap_page,
+       .alloc                          = gart_alloc_coherent,
+       .free                           = gart_free_coherent,
+       .mapping_error                  = gart_mapping_error,
+};
+
+static void gart_iommu_shutdown(void)
+{
+       struct pci_dev *dev;
+       int i;
+
+       /* don't shutdown it if there is AGP installed */
+       if (!no_agp)
+               return;
+
+       if (!amd_nb_has_feature(AMD_NB_GART))
+               return;
+
+       for (i = 0; i < amd_nb_num(); i++) {
+               u32 ctl;
+
+               dev = node_to_amd_nb(i)->misc;
+               pci_read_config_dword(dev, AMD64_GARTAPERTURECTL, &ctl);
+
+               ctl &= ~GARTEN;
+
+               pci_write_config_dword(dev, AMD64_GARTAPERTURECTL, ctl);
+       }
+}
+
+int __init gart_iommu_init(void)
+{
+       struct agp_kern_info info;
+       unsigned long iommu_start;
+       unsigned long aper_base, aper_size;
+       unsigned long start_pfn, end_pfn;
+       unsigned long scratch;
+       long i;
+
+       if (!amd_nb_has_feature(AMD_NB_GART))
+               return 0;
+
+#ifndef CONFIG_AGP_AMD64
+       no_agp = 1;
+#else
+       /* Makefile puts PCI initialization via subsys_initcall first. */
+       /* Add other AMD AGP bridge drivers here */
+       no_agp = no_agp ||
+               (agp_amd64_init() < 0) ||
+               (agp_copy_info(agp_bridge, &info) < 0);
+#endif
+
+       if (no_iommu ||
+           (!force_iommu && max_pfn <= MAX_DMA32_PFN) ||
+           !gart_iommu_aperture ||
+           (no_agp && init_amd_gatt(&info) < 0)) {
+               if (max_pfn > MAX_DMA32_PFN) {
+                       pr_warning("More than 4GB of memory but GART IOMMU not available.\n");
+                       pr_warning("falling back to iommu=soft.\n");
+               }
+               return 0;
+       }
+
+       /* need to map that range */
+       aper_size       = info.aper_size << 20;
+       aper_base       = info.aper_base;
+       end_pfn         = (aper_base>>PAGE_SHIFT) + (aper_size>>PAGE_SHIFT);
+
+       start_pfn = PFN_DOWN(aper_base);
+       if (!pfn_range_is_mapped(start_pfn, end_pfn))
+               init_memory_mapping(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
+
+       pr_info("PCI-DMA: using GART IOMMU.\n");
+       iommu_size = check_iommu_size(info.aper_base, aper_size);
+       iommu_pages = iommu_size >> PAGE_SHIFT;
+
+       iommu_gart_bitmap = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+                                                     get_order(iommu_pages/8));
+       if (!iommu_gart_bitmap)
+               panic("Cannot allocate iommu bitmap\n");
+
+#ifdef CONFIG_IOMMU_LEAK
+       if (leak_trace) {
+               int ret;
+
+               ret = dma_debug_resize_entries(iommu_pages);
+               if (ret)
+                       pr_debug("PCI-DMA: Cannot trace all the entries\n");
+       }
+#endif
+
+       /*
+        * Out of IOMMU space handling.
+        * Reserve some invalid pages at the beginning of the GART.
+        */
+       bitmap_set(iommu_gart_bitmap, 0, EMERGENCY_PAGES);
+
+       pr_info("PCI-DMA: Reserving %luMB of IOMMU area in the AGP aperture\n",
+              iommu_size >> 20);
+
+       agp_memory_reserved     = iommu_size;
+       iommu_start             = aper_size - iommu_size;
+       iommu_bus_base          = info.aper_base + iommu_start;
+       bad_dma_addr            = iommu_bus_base;
+       iommu_gatt_base         = agp_gatt_table + (iommu_start>>PAGE_SHIFT);
+
+       /*
+        * Unmap the IOMMU part of the GART. The alias of the page is
+        * always mapped with cache enabled and there is no full cache
+        * coherency across the GART remapping. The unmapping avoids
+        * automatic prefetches from the CPU allocating cache lines in
+        * there. All CPU accesses are done via the direct mapping to
+        * the backing memory. The GART address is only used by PCI
+        * devices.
+        */
+       set_memory_np((unsigned long)__va(iommu_bus_base),
+                               iommu_size >> PAGE_SHIFT);
+       /*
+        * Tricky. The GART table remaps the physical memory range,
+        * so the CPU wont notice potential aliases and if the memory
+        * is remapped to UC later on, we might surprise the PCI devices
+        * with a stray writeout of a cacheline. So play it sure and
+        * do an explicit, full-scale wbinvd() _after_ having marked all
+        * the pages as Not-Present:
+        */
+       wbinvd();
+
+       /*
+        * Now all caches are flushed and we can safely enable
+        * GART hardware.  Doing it early leaves the possibility
+        * of stale cache entries that can lead to GART PTE
+        * errors.
+        */
+       enable_gart_translations();
+
+       /*
+        * Try to workaround a bug (thanks to BenH):
+        * Set unmapped entries to a scratch page instead of 0.
+        * Any prefetches that hit unmapped entries won't get an bus abort
+        * then. (P2P bridge may be prefetching on DMA reads).
+        */
+       scratch = get_zeroed_page(GFP_KERNEL);
+       if (!scratch)
+               panic("Cannot allocate iommu scratch page");
+       gart_unmapped_entry = GPTE_ENCODE(__pa(scratch));
+       for (i = EMERGENCY_PAGES; i < iommu_pages; i++)
+               iommu_gatt_base[i] = gart_unmapped_entry;
+
+       flush_gart();
+       dma_ops = &gart_dma_ops;
+       x86_platform.iommu_shutdown = gart_iommu_shutdown;
+       swiotlb = 0;
+
+       return 0;
+}
+
+void __init gart_parse_options(char *p)
+{
+       int arg;
+
+#ifdef CONFIG_IOMMU_LEAK
+       if (!strncmp(p, "leak", 4)) {
+               leak_trace = 1;
+               p += 4;
+               if (*p == '=')
+                       ++p;
+               if (isdigit(*p) && get_option(&p, &arg))
+                       iommu_leak_pages = arg;
+       }
+#endif
+       if (isdigit(*p) && get_option(&p, &arg))
+               iommu_size = arg;
+       if (!strncmp(p, "fullflush", 9))
+               iommu_fullflush = 1;
+       if (!strncmp(p, "nofullflush", 11))
+               iommu_fullflush = 0;
+       if (!strncmp(p, "noagp", 5))
+               no_agp = 1;
+       if (!strncmp(p, "noaperture", 10))
+               fix_aperture = 0;
+       /* duplicated from pci-dma.c */
+       if (!strncmp(p, "force", 5))
+               gart_iommu_aperture_allowed = 1;
+       if (!strncmp(p, "allowed", 7))
+               gart_iommu_aperture_allowed = 1;
+       if (!strncmp(p, "memaper", 7)) {
+               fallback_aper_force = 1;
+               p += 7;
+               if (*p == '=') {
+                       ++p;
+                       if (get_option(&p, &arg))
+                               fallback_aper_order = arg;
+               }
+       }
+}
+IOMMU_INIT_POST(gart_iommu_hole_init);