Initial import

1 files changed, 965 insertions, 0 deletions

diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
new file mode 100644
index 000000000..eddee7720
--- /dev/null
+++ b/arch/alpha/kernel/pci_iommu.c
@@ -0,0 +1,965 @@
+/*
+ *	linux/arch/alpha/kernel/pci_iommu.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/pci.h>
+#include <linux/gfp.h>
+#include <linux/bootmem.h>
+#include <linux/export.h>
+#include <linux/scatterlist.h>
+#include <linux/log2.h>
+#include <linux/dma-mapping.h>
+#include <linux/iommu-helper.h>
+
+#include <asm/io.h>
+#include <asm/hwrpb.h>
+
+#include "proto.h"
+#include "pci_impl.h"
+
+
+#define DEBUG_ALLOC 0
+#if DEBUG_ALLOC > 0
+# define DBGA(args...)		printk(KERN_DEBUG args)
+#else
+# define DBGA(args...)
+#endif
+#if DEBUG_ALLOC > 1
+# define DBGA2(args...)		printk(KERN_DEBUG args)
+#else
+# define DBGA2(args...)
+#endif
+
+#define DEBUG_NODIRECT 0
+
+#define ISA_DMA_MASK		0x00ffffff
+
+static inline unsigned long
+mk_iommu_pte(unsigned long paddr)
+{
+	return (paddr >> (PAGE_SHIFT-1)) | 1;
+}
+
+/* Return the minimum of MAX or the first power of two larger
+   than main memory.  */
+
+unsigned long
+size_for_memory(unsigned long max)
+{
+	unsigned long mem = max_low_pfn << PAGE_SHIFT;
+	if (mem < max)
+		max = roundup_pow_of_two(mem);
+	return max;
+}
+
+struct pci_iommu_arena * __init
+iommu_arena_new_node(int nid, struct pci_controller *hose, dma_addr_t base,
+		     unsigned long window_size, unsigned long align)
+{
+	unsigned long mem_size;
+	struct pci_iommu_arena *arena;
+
+	mem_size = window_size / (PAGE_SIZE / sizeof(unsigned long));
+
+	/* Note that the TLB lookup logic uses bitwise concatenation,
+	   not addition, so the required arena alignment is based on
+	   the size of the window.  Retain the align parameter so that
+	   particular systems can over-align the arena.  */
+	if (align < mem_size)
+		align = mem_size;
+
+
+#ifdef CONFIG_DISCONTIGMEM
+
+	arena = alloc_bootmem_node(NODE_DATA(nid), sizeof(*arena));
+	if (!NODE_DATA(nid) || !arena) {
+		printk("%s: couldn't allocate arena from node %d\n"
+		       "    falling back to system-wide allocation\n",
+		       __func__, nid);
+		arena = alloc_bootmem(sizeof(*arena));
+	}
+
+	arena->ptes = __alloc_bootmem_node(NODE_DATA(nid), mem_size, align, 0);
+	if (!NODE_DATA(nid) || !arena->ptes) {
+		printk("%s: couldn't allocate arena ptes from node %d\n"
+		       "    falling back to system-wide allocation\n",
+		       __func__, nid);
+		arena->ptes = __alloc_bootmem(mem_size, align, 0);
+	}
+
+#else /* CONFIG_DISCONTIGMEM */
+
+	arena = alloc_bootmem(sizeof(*arena));
+	arena->ptes = __alloc_bootmem(mem_size, align, 0);
+
+#endif /* CONFIG_DISCONTIGMEM */
+
+	spin_lock_init(&arena->lock);
+	arena->hose = hose;
+	arena->dma_base = base;
+	arena->size = window_size;
+	arena->next_entry = 0;
+
+	/* Align allocations to a multiple of a page size.  Not needed
+	   unless there are chip bugs.  */
+	arena->align_entry = 1;
+
+	return arena;
+}
+
+struct pci_iommu_arena * __init
+iommu_arena_new(struct pci_controller *hose, dma_addr_t base,
+		unsigned long window_size, unsigned long align)
+{
+	return iommu_arena_new_node(0, hose, base, window_size, align);
+}
+
+/* Must be called with the arena lock held */
+static long
+iommu_arena_find_pages(struct device *dev, struct pci_iommu_arena *arena,
+		       long n, long mask)
+{
+	unsigned long *ptes;
+	long i, p, nent;
+	int pass = 0;
+	unsigned long base;
+	unsigned long boundary_size;
+
+	base = arena->dma_base >> PAGE_SHIFT;
+	if (dev) {
+		boundary_size = dma_get_seg_boundary(dev) + 1;
+		boundary_size >>= PAGE_SHIFT;
+	} else {
+		boundary_size = 1UL << (32 - PAGE_SHIFT);
+	}
+
+	/* Search forward for the first mask-aligned sequence of N free ptes */
+	ptes = arena->ptes;
+	nent = arena->size >> PAGE_SHIFT;
+	p = ALIGN(arena->next_entry, mask + 1);
+	i = 0;
+
+again:
+	while (i < n && p+i < nent) {
+		if (!i && iommu_is_span_boundary(p, n, base, boundary_size)) {
+			p = ALIGN(p + 1, mask + 1);
+			goto again;
+		}
+
+		if (ptes[p+i])
+			p = ALIGN(p + i + 1, mask + 1), i = 0;
+		else
+			i = i + 1;
+	}
+
+	if (i < n) {
+		if (pass < 1) {
+			/*
+			 * Reached the end.  Flush the TLB and restart
+			 * the search from the beginning.
+			*/
+			alpha_mv.mv_pci_tbi(arena->hose, 0, -1);
+
+			pass++;
+			p = 0;
+			i = 0;
+			goto again;
+		} else
+			return -1;
+	}
+
+	/* Success. It's the responsibility of the caller to mark them
+	   in use before releasing the lock */
+	return p;
+}
+
+static long
+iommu_arena_alloc(struct device *dev, struct pci_iommu_arena *arena, long n,
+		  unsigned int align)
+{
+	unsigned long flags;
+	unsigned long *ptes;
+	long i, p, mask;
+
+	spin_lock_irqsave(&arena->lock, flags);
+
+	/* Search for N empty ptes */
+	ptes = arena->ptes;
+	mask = max(align, arena->align_entry) - 1;
+	p = iommu_arena_find_pages(dev, arena, n, mask);
+	if (p < 0) {
+		spin_unlock_irqrestore(&arena->lock, flags);
+		return -1;
+	}
+
+	/* Success.  Mark them all in use, ie not zero and invalid
+	   for the iommu tlb that could load them from under us.
+	   The chip specific bits will fill this in with something
+	   kosher when we return.  */
+	for (i = 0; i < n; ++i)
+		ptes[p+i] = IOMMU_INVALID_PTE;
+
+	arena->next_entry = p + n;
+	spin_unlock_irqrestore(&arena->lock, flags);
+
+	return p;
+}
+
+static void
+iommu_arena_free(struct pci_iommu_arena *arena, long ofs, long n)
+{
+	unsigned long *p;
+	long i;
+
+	p = arena->ptes + ofs;
+	for (i = 0; i < n; ++i)
+		p[i] = 0;
+}
+
+/*
+ * True if the machine supports DAC addressing, and DEV can
+ * make use of it given MASK.
+ */
+static int pci_dac_dma_supported(struct pci_dev *dev, u64 mask)
+{
+	dma_addr_t dac_offset = alpha_mv.pci_dac_offset;
+	int ok = 1;
+
+	/* If this is not set, the machine doesn't support DAC at all.  */
+	if (dac_offset == 0)
+		ok = 0;
+
+	/* The device has to be able to address our DAC bit.  */
+	if ((dac_offset & dev->dma_mask) != dac_offset)
+		ok = 0;
+
+	/* If both conditions above are met, we are fine. */
+	DBGA("pci_dac_dma_supported %s from %pf\n",
+	     ok ? "yes" : "no", __builtin_return_address(0));
+
+	return ok;
+}
+
+/* Map a single buffer of the indicated size for PCI DMA in streaming
+   mode.  The 32-bit PCI bus mastering address to use is returned.
+   Once the device is given the dma address, the device owns this memory
+   until either pci_unmap_single or pci_dma_sync_single is performed.  */
+
+static dma_addr_t
+pci_map_single_1(struct pci_dev *pdev, void *cpu_addr, size_t size,
+		 int dac_allowed)
+{
+	struct pci_controller *hose = pdev ? pdev->sysdata : pci_isa_hose;
+	dma_addr_t max_dma = pdev ? pdev->dma_mask : ISA_DMA_MASK;
+	struct pci_iommu_arena *arena;
+	long npages, dma_ofs, i;
+	unsigned long paddr;
+	dma_addr_t ret;
+	unsigned int align = 0;
+	struct device *dev = pdev ? &pdev->dev : NULL;
+
+	paddr = __pa(cpu_addr);
+
+#if !DEBUG_NODIRECT
+	/* First check to see if we can use the direct map window.  */
+	if (paddr + size + __direct_map_base - 1 <= max_dma
+	    && paddr + size <= __direct_map_size) {
+		ret = paddr + __direct_map_base;
+
+		DBGA2("pci_map_single: [%p,%zx] -> direct %llx from %pf\n",
+		      cpu_addr, size, ret, __builtin_return_address(0));
+
+		return ret;
+	}
+#endif
+
+	/* Next, use DAC if selected earlier.  */
+	if (dac_allowed) {
+		ret = paddr + alpha_mv.pci_dac_offset;
+
+		DBGA2("pci_map_single: [%p,%zx] -> DAC %llx from %pf\n",
+		      cpu_addr, size, ret, __builtin_return_address(0));
+
+		return ret;
+	}
+
+	/* If the machine doesn't define a pci_tbi routine, we have to
+	   assume it doesn't support sg mapping, and, since we tried to
+	   use direct_map above, it now must be considered an error. */
+	if (! alpha_mv.mv_pci_tbi) {
+		printk_once(KERN_WARNING "pci_map_single: no HW sg\n");
+		return 0;
+	}
+
+	arena = hose->sg_pci;
+	if (!arena || arena->dma_base + arena->size - 1 > max_dma)
+		arena = hose->sg_isa;
+
+	npages = iommu_num_pages(paddr, size, PAGE_SIZE);
+
+	/* Force allocation to 64KB boundary for ISA bridges. */
+	if (pdev && pdev == isa_bridge)
+		align = 8;
+	dma_ofs = iommu_arena_alloc(dev, arena, npages, align);
+	if (dma_ofs < 0) {
+		printk(KERN_WARNING "pci_map_single failed: "
+		       "could not allocate dma page tables\n");
+		return 0;
+	}
+
+	paddr &= PAGE_MASK;
+	for (i = 0; i < npages; ++i, paddr += PAGE_SIZE)
+		arena->ptes[i + dma_ofs] = mk_iommu_pte(paddr);
+
+	ret = arena->dma_base + dma_ofs * PAGE_SIZE;
+	ret += (unsigned long)cpu_addr & ~PAGE_MASK;
+
+	DBGA2("pci_map_single: [%p,%zx] np %ld -> sg %llx from %pf\n",
+	      cpu_addr, size, npages, ret, __builtin_return_address(0));
+
+	return ret;
+}
+
+/* Helper for generic DMA-mapping functions. */
+static struct pci_dev *alpha_gendev_to_pci(struct device *dev)
+{
+	if (dev && dev_is_pci(dev))
+		return to_pci_dev(dev);
+
+	/* Assume that non-PCI devices asking for DMA are either ISA or EISA,
+	   BUG() otherwise. */
+	BUG_ON(!isa_bridge);
+
+	/* Assume non-busmaster ISA DMA when dma_mask is not set (the ISA
+	   bridge is bus master then). */
+	if (!dev || !dev->dma_mask || !*dev->dma_mask)
+		return isa_bridge;
+
+	/* For EISA bus masters, return isa_bridge (it might have smaller
+	   dma_mask due to wiring limitations). */
+	if (*dev->dma_mask >= isa_bridge->dma_mask)
+		return isa_bridge;
+
+	/* This assumes ISA bus master with dma_mask 0xffffff. */
+	return NULL;
+}
+
+static dma_addr_t alpha_pci_map_page(struct device *dev, struct page *page,
+				     unsigned long offset, size_t size,
+				     enum dma_data_direction dir,
+				     struct dma_attrs *attrs)
+{
+	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
+	int dac_allowed;
+
+	BUG_ON(dir == PCI_DMA_NONE);
+
+	dac_allowed = pdev ? pci_dac_dma_supported(pdev, pdev->dma_mask) : 0; 
+	return pci_map_single_1(pdev, (char *)page_address(page) + offset, 
+				size, dac_allowed);
+}
+
+/* Unmap a single streaming mode DMA translation.  The DMA_ADDR and
+   SIZE must match what was provided for in a previous pci_map_single
+   call.  All other usages are undefined.  After this call, reads by
+   the cpu to the buffer are guaranteed to see whatever the device
+   wrote there.  */
+
+static void alpha_pci_unmap_page(struct device *dev, dma_addr_t dma_addr,
+				 size_t size, enum dma_data_direction dir,
+				 struct dma_attrs *attrs)
+{
+	unsigned long flags;
+	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
+	struct pci_controller *hose = pdev ? pdev->sysdata : pci_isa_hose;
+	struct pci_iommu_arena *arena;
+	long dma_ofs, npages;
+
+	BUG_ON(dir == PCI_DMA_NONE);
+
+	if (dma_addr >= __direct_map_base
+	    && dma_addr < __direct_map_base + __direct_map_size) {
+		/* Nothing to do.  */
+
+		DBGA2("pci_unmap_single: direct [%llx,%zx] from %pf\n",
+		      dma_addr, size, __builtin_return_address(0));
+
+		return;
+	}
+
+	if (dma_addr > 0xffffffff) {
+		DBGA2("pci64_unmap_single: DAC [%llx,%zx] from %pf\n",
+		      dma_addr, size, __builtin_return_address(0));
+		return;
+	}
+
+	arena = hose->sg_pci;
+	if (!arena || dma_addr < arena->dma_base)
+		arena = hose->sg_isa;
+
+	dma_ofs = (dma_addr - arena->dma_base) >> PAGE_SHIFT;
+	if (dma_ofs * PAGE_SIZE >= arena->size) {
+		printk(KERN_ERR "Bogus pci_unmap_single: dma_addr %llx "
+		       " base %llx size %x\n",
+		       dma_addr, arena->dma_base, arena->size);
+		return;
+		BUG();
+	}
+
+	npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
+
+	spin_lock_irqsave(&arena->lock, flags);
+
+	iommu_arena_free(arena, dma_ofs, npages);
+
+        /* If we're freeing ptes above the `next_entry' pointer (they
+           may have snuck back into the TLB since the last wrap flush),
+           we need to flush the TLB before reallocating the latter.  */
+	if (dma_ofs >= arena->next_entry)
+		alpha_mv.mv_pci_tbi(hose, dma_addr, dma_addr + size - 1);
+
+	spin_unlock_irqrestore(&arena->lock, flags);
+
+	DBGA2("pci_unmap_single: sg [%llx,%zx] np %ld from %pf\n",
+	      dma_addr, size, npages, __builtin_return_address(0));
+}
+
+/* Allocate and map kernel buffer using consistent mode DMA for PCI
+   device.  Returns non-NULL cpu-view pointer to the buffer if
+   successful and sets *DMA_ADDRP to the pci side dma address as well,
+   else DMA_ADDRP is undefined.  */
+
+static void *alpha_pci_alloc_coherent(struct device *dev, size_t size,
+				      dma_addr_t *dma_addrp, gfp_t gfp,
+				      struct dma_attrs *attrs)
+{
+	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
+	void *cpu_addr;
+	long order = get_order(size);
+
+	gfp &= ~GFP_DMA;
+
+try_again:
+	cpu_addr = (void *)__get_free_pages(gfp, order);
+	if (! cpu_addr) {
+		printk(KERN_INFO "pci_alloc_consistent: "
+		       "get_free_pages failed from %pf\n",
+			__builtin_return_address(0));
+		/* ??? Really atomic allocation?  Otherwise we could play
+		   with vmalloc and sg if we can't find contiguous memory.  */
+		return NULL;
+	}
+	memset(cpu_addr, 0, size);
+
+	*dma_addrp = pci_map_single_1(pdev, cpu_addr, size, 0);
+	if (*dma_addrp == 0) {
+		free_pages((unsigned long)cpu_addr, order);
+		if (alpha_mv.mv_pci_tbi || (gfp & GFP_DMA))
+			return NULL;
+		/* The address doesn't fit required mask and we
+		   do not have iommu. Try again with GFP_DMA. */
+		gfp |= GFP_DMA;
+		goto try_again;
+	}
+
+	DBGA2("pci_alloc_consistent: %zx -> [%p,%llx] from %pf\n",
+	      size, cpu_addr, *dma_addrp, __builtin_return_address(0));
+
+	return cpu_addr;
+}
+
+/* Free and unmap a consistent DMA buffer.  CPU_ADDR and DMA_ADDR must
+   be values that were returned from pci_alloc_consistent.  SIZE must
+   be the same as what as passed into pci_alloc_consistent.
+   References to the memory and mappings associated with CPU_ADDR or
+   DMA_ADDR past this call are illegal.  */
+
+static void alpha_pci_free_coherent(struct device *dev, size_t size,
+				    void *cpu_addr, dma_addr_t dma_addr,
+				    struct dma_attrs *attrs)
+{
+	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
+	pci_unmap_single(pdev, dma_addr, size, PCI_DMA_BIDIRECTIONAL);
+	free_pages((unsigned long)cpu_addr, get_order(size));
+
+	DBGA2("pci_free_consistent: [%llx,%zx] from %pf\n",
+	      dma_addr, size, __builtin_return_address(0));
+}
+
+/* Classify the elements of the scatterlist.  Write dma_address
+   of each element with:
+	0   : Followers all physically adjacent.
+	1   : Followers all virtually adjacent.
+	-1  : Not leader, physically adjacent to previous.
+	-2  : Not leader, virtually adjacent to previous.
+   Write dma_length of each leader with the combined lengths of
+   the mergable followers.  */
+
+#define SG_ENT_VIRT_ADDRESS(SG) (sg_virt((SG)))
+#define SG_ENT_PHYS_ADDRESS(SG) __pa(SG_ENT_VIRT_ADDRESS(SG))
+
+static void
+sg_classify(struct device *dev, struct scatterlist *sg, struct scatterlist *end,
+	    int virt_ok)
+{
+	unsigned long next_paddr;
+	struct scatterlist *leader;
+	long leader_flag, leader_length;
+	unsigned int max_seg_size;
+
+	leader = sg;
+	leader_flag = 0;
+	leader_length = leader->length;
+	next_paddr = SG_ENT_PHYS_ADDRESS(leader) + leader_length;
+
+	/* we will not marge sg without device. */
+	max_seg_size = dev ? dma_get_max_seg_size(dev) : 0;
+	for (++sg; sg < end; ++sg) {
+		unsigned long addr, len;
+		addr = SG_ENT_PHYS_ADDRESS(sg);
+		len = sg->length;
+
+		if (leader_length + len > max_seg_size)
+			goto new_segment;
+
+		if (next_paddr == addr) {
+			sg->dma_address = -1;
+			leader_length += len;
+		} else if (((next_paddr | addr) & ~PAGE_MASK) == 0 && virt_ok) {
+			sg->dma_address = -2;
+			leader_flag = 1;
+			leader_length += len;
+		} else {
+new_segment:
+			leader->dma_address = leader_flag;
+			leader->dma_length = leader_length;
+			leader = sg;
+			leader_flag = 0;
+			leader_length = len;
+		}
+
+		next_paddr = addr + len;
+	}
+
+	leader->dma_address = leader_flag;
+	leader->dma_length = leader_length;
+}
+
+/* Given a scatterlist leader, choose an allocation method and fill
+   in the blanks.  */
+
+static int
+sg_fill(struct device *dev, struct scatterlist *leader, struct scatterlist *end,
+	struct scatterlist *out, struct pci_iommu_arena *arena,
+	dma_addr_t max_dma, int dac_allowed)
+{
+	unsigned long paddr = SG_ENT_PHYS_ADDRESS(leader);
+	long size = leader->dma_length;
+	struct scatterlist *sg;
+	unsigned long *ptes;
+	long npages, dma_ofs, i;
+
+#if !DEBUG_NODIRECT
+	/* If everything is physically contiguous, and the addresses
+	   fall into the direct-map window, use it.  */
+	if (leader->dma_address == 0
+	    && paddr + size + __direct_map_base - 1 <= max_dma
+	    && paddr + size <= __direct_map_size) {
+		out->dma_address = paddr + __direct_map_base;
+		out->dma_length = size;
+
+		DBGA("    sg_fill: [%p,%lx] -> direct %llx\n",
+		     __va(paddr), size, out->dma_address);
+
+		return 0;
+	}
+#endif
+
+	/* If physically contiguous and DAC is available, use it.  */
+	if (leader->dma_address == 0 && dac_allowed) {
+		out->dma_address = paddr + alpha_mv.pci_dac_offset;
+		out->dma_length = size;
+
+		DBGA("    sg_fill: [%p,%lx] -> DAC %llx\n",
+		     __va(paddr), size, out->dma_address);
+
+		return 0;
+	}
+
+	/* Otherwise, we'll use the iommu to make the pages virtually
+	   contiguous.  */
+
+	paddr &= ~PAGE_MASK;
+	npages = iommu_num_pages(paddr, size, PAGE_SIZE);
+	dma_ofs = iommu_arena_alloc(dev, arena, npages, 0);
+	if (dma_ofs < 0) {
+		/* If we attempted a direct map above but failed, die.  */
+		if (leader->dma_address == 0)
+			return -1;
+
+		/* Otherwise, break up the remaining virtually contiguous
+		   hunks into individual direct maps and retry.  */
+		sg_classify(dev, leader, end, 0);
+		return sg_fill(dev, leader, end, out, arena, max_dma, dac_allowed);
+	}
+
+	out->dma_address = arena->dma_base + dma_ofs*PAGE_SIZE + paddr;
+	out->dma_length = size;
+
+	DBGA("    sg_fill: [%p,%lx] -> sg %llx np %ld\n",
+	     __va(paddr), size, out->dma_address, npages);
+
+	/* All virtually contiguous.  We need to find the length of each
+	   physically contiguous subsegment to fill in the ptes.  */
+	ptes = &arena->ptes[dma_ofs];
+	sg = leader;
+	do {
+#if DEBUG_ALLOC > 0
+		struct scatterlist *last_sg = sg;
+#endif
+
+		size = sg->length;
+		paddr = SG_ENT_PHYS_ADDRESS(sg);
+
+		while (sg+1 < end && (int) sg[1].dma_address == -1) {
+			size += sg[1].length;
+			sg++;
+		}
+
+		npages = iommu_num_pages(paddr, size, PAGE_SIZE);
+
+		paddr &= PAGE_MASK;
+		for (i = 0; i < npages; ++i, paddr += PAGE_SIZE)
+			*ptes++ = mk_iommu_pte(paddr);
+
+#if DEBUG_ALLOC > 0
+		DBGA("    (%ld) [%p,%x] np %ld\n",
+		     last_sg - leader, SG_ENT_VIRT_ADDRESS(last_sg),
+		     last_sg->length, npages);
+		while (++last_sg <= sg) {
+			DBGA("        (%ld) [%p,%x] cont\n",
+			     last_sg - leader, SG_ENT_VIRT_ADDRESS(last_sg),
+			     last_sg->length);
+		}
+#endif
+	} while (++sg < end && (int) sg->dma_address < 0);
+
+	return 1;
+}
+
+static int alpha_pci_map_sg(struct device *dev, struct scatterlist *sg,
+			    int nents, enum dma_data_direction dir,
+			    struct dma_attrs *attrs)
+{
+	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
+	struct scatterlist *start, *end, *out;
+	struct pci_controller *hose;
+	struct pci_iommu_arena *arena;
+	dma_addr_t max_dma;
+	int dac_allowed;
+
+	BUG_ON(dir == PCI_DMA_NONE);
+
+	dac_allowed = dev ? pci_dac_dma_supported(pdev, pdev->dma_mask) : 0;
+
+	/* Fast path single entry scatterlists.  */
+	if (nents == 1) {
+		sg->dma_length = sg->length;
+		sg->dma_address
+		  = pci_map_single_1(pdev, SG_ENT_VIRT_ADDRESS(sg),
+				     sg->length, dac_allowed);
+		return sg->dma_address != 0;
+	}
+
+	start = sg;
+	end = sg + nents;
+
+	/* First, prepare information about the entries.  */
+	sg_classify(dev, sg, end, alpha_mv.mv_pci_tbi != 0);
+
+	/* Second, figure out where we're going to map things.  */
+	if (alpha_mv.mv_pci_tbi) {
+		hose = pdev ? pdev->sysdata : pci_isa_hose;
+		max_dma = pdev ? pdev->dma_mask : ISA_DMA_MASK;
+		arena = hose->sg_pci;
+		if (!arena || arena->dma_base + arena->size - 1 > max_dma)
+			arena = hose->sg_isa;
+	} else {
+		max_dma = -1;
+		arena = NULL;
+		hose = NULL;
+	}
+
+	/* Third, iterate over the scatterlist leaders and allocate
+	   dma space as needed.  */
+	for (out = sg; sg < end; ++sg) {
+		if ((int) sg->dma_address < 0)
+			continue;
+		if (sg_fill(dev, sg, end, out, arena, max_dma, dac_allowed) < 0)
+			goto error;
+		out++;
+	}
+
+	/* Mark the end of the list for pci_unmap_sg.  */
+	if (out < end)
+		out->dma_length = 0;
+
+	if (out - start == 0)
+		printk(KERN_WARNING "pci_map_sg failed: no entries?\n");
+	DBGA("pci_map_sg: %ld entries\n", out - start);
+
+	return out - start;
+
+ error:
+	printk(KERN_WARNING "pci_map_sg failed: "
+	       "could not allocate dma page tables\n");
+
+	/* Some allocation failed while mapping the scatterlist
+	   entries.  Unmap them now.  */
+	if (out > start)
+		pci_unmap_sg(pdev, start, out - start, dir);
+	return 0;
+}
+
+/* Unmap a set of streaming mode DMA translations.  Again, cpu read
+   rules concerning calls here are the same as for pci_unmap_single()
+   above.  */
+
+static void alpha_pci_unmap_sg(struct device *dev, struct scatterlist *sg,
+			       int nents, enum dma_data_direction dir,
+			       struct dma_attrs *attrs)
+{
+	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
+	unsigned long flags;
+	struct pci_controller *hose;
+	struct pci_iommu_arena *arena;
+	struct scatterlist *end;
+	dma_addr_t max_dma;
+	dma_addr_t fbeg, fend;
+
+	BUG_ON(dir == PCI_DMA_NONE);
+
+	if (! alpha_mv.mv_pci_tbi)
+		return;
+
+	hose = pdev ? pdev->sysdata : pci_isa_hose;
+	max_dma = pdev ? pdev->dma_mask : ISA_DMA_MASK;
+	arena = hose->sg_pci;
+	if (!arena || arena->dma_base + arena->size - 1 > max_dma)
+		arena = hose->sg_isa;
+
+	fbeg = -1, fend = 0;
+
+	spin_lock_irqsave(&arena->lock, flags);
+
+	for (end = sg + nents; sg < end; ++sg) {
+		dma_addr_t addr;
+		size_t size;
+		long npages, ofs;
+		dma_addr_t tend;
+
+		addr = sg->dma_address;
+		size = sg->dma_length;
+		if (!size)
+			break;
+
+		if (addr > 0xffffffff) {
+			/* It's a DAC address -- nothing to do.  */
+			DBGA("    (%ld) DAC [%llx,%zx]\n",
+			      sg - end + nents, addr, size);
+			continue;
+		}
+
+		if (addr >= __direct_map_base
+		    && addr < __direct_map_base + __direct_map_size) {
+			/* Nothing to do.  */
+			DBGA("    (%ld) direct [%llx,%zx]\n",
+			      sg - end + nents, addr, size);
+			continue;
+		}
+
+		DBGA("    (%ld) sg [%llx,%zx]\n",
+		     sg - end + nents, addr, size);
+
+		npages = iommu_num_pages(addr, size, PAGE_SIZE);
+		ofs = (addr - arena->dma_base) >> PAGE_SHIFT;
+		iommu_arena_free(arena, ofs, npages);
+
+		tend = addr + size - 1;
+		if (fbeg > addr) fbeg = addr;
+		if (fend < tend) fend = tend;
+	}
+
+        /* If we're freeing ptes above the `next_entry' pointer (they
+           may have snuck back into the TLB since the last wrap flush),
+           we need to flush the TLB before reallocating the latter.  */
+	if ((fend - arena->dma_base) >> PAGE_SHIFT >= arena->next_entry)
+		alpha_mv.mv_pci_tbi(hose, fbeg, fend);
+
+	spin_unlock_irqrestore(&arena->lock, flags);
+
+	DBGA("pci_unmap_sg: %ld entries\n", nents - (end - sg));
+}
+
+/* Return whether the given PCI device DMA address mask can be
+   supported properly.  */
+
+static int alpha_pci_supported(struct device *dev, u64 mask)
+{
+	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
+	struct pci_controller *hose;
+	struct pci_iommu_arena *arena;
+
+	/* If there exists a direct map, and the mask fits either
+	   the entire direct mapped space or the total system memory as
+	   shifted by the map base */
+	if (__direct_map_size != 0
+	    && (__direct_map_base + __direct_map_size - 1 <= mask ||
+		__direct_map_base + (max_low_pfn << PAGE_SHIFT) - 1 <= mask))
+		return 1;
+
+	/* Check that we have a scatter-gather arena that fits.  */
+	hose = pdev ? pdev->sysdata : pci_isa_hose;
+	arena = hose->sg_isa;
+	if (arena && arena->dma_base + arena->size - 1 <= mask)
+		return 1;
+	arena = hose->sg_pci;
+	if (arena && arena->dma_base + arena->size - 1 <= mask)
+		return 1;
+
+	/* As last resort try ZONE_DMA.  */
+	if (!__direct_map_base && MAX_DMA_ADDRESS - IDENT_ADDR - 1 <= mask)
+		return 1;
+
+	return 0;
+}
+
+
+/*
+ * AGP GART extensions to the IOMMU
+ */
+int
+iommu_reserve(struct pci_iommu_arena *arena, long pg_count, long align_mask) 
+{
+	unsigned long flags;
+	unsigned long *ptes;
+	long i, p;
+
+	if (!arena) return -EINVAL;
+
+	spin_lock_irqsave(&arena->lock, flags);
+
+	/* Search for N empty ptes.  */
+	ptes = arena->ptes;
+	p = iommu_arena_find_pages(NULL, arena, pg_count, align_mask);
+	if (p < 0) {
+		spin_unlock_irqrestore(&arena->lock, flags);
+		return -1;
+	}
+
+	/* Success.  Mark them all reserved (ie not zero and invalid)
+	   for the iommu tlb that could load them from under us.
+	   They will be filled in with valid bits by _bind() */
+	for (i = 0; i < pg_count; ++i)
+		ptes[p+i] = IOMMU_RESERVED_PTE;
+
+	arena->next_entry = p + pg_count;
+	spin_unlock_irqrestore(&arena->lock, flags);
+
+	return p;
+}
+
+int 
+iommu_release(struct pci_iommu_arena *arena, long pg_start, long pg_count)
+{
+	unsigned long *ptes;
+	long i;
+
+	if (!arena) return -EINVAL;
+
+	ptes = arena->ptes;
+
+	/* Make sure they're all reserved first... */
+	for(i = pg_start; i < pg_start + pg_count; i++)
+		if (ptes[i] != IOMMU_RESERVED_PTE)
+			return -EBUSY;
+
+	iommu_arena_free(arena, pg_start, pg_count);
+	return 0;
+}
+
+int
+iommu_bind(struct pci_iommu_arena *arena, long pg_start, long pg_count, 
+	   struct page **pages)
+{
+	unsigned long flags;
+	unsigned long *ptes;
+	long i, j;
+
+	if (!arena) return -EINVAL;
+	
+	spin_lock_irqsave(&arena->lock, flags);
+
+	ptes = arena->ptes;
+
+	for(j = pg_start; j < pg_start + pg_count; j++) {
+		if (ptes[j] != IOMMU_RESERVED_PTE) {
+			spin_unlock_irqrestore(&arena->lock, flags);
+			return -EBUSY;
+		}
+	}
+		
+	for(i = 0, j = pg_start; i < pg_count; i++, j++)
+		ptes[j] = mk_iommu_pte(page_to_phys(pages[i]));
+
+	spin_unlock_irqrestore(&arena->lock, flags);
+
+	return 0;
+}
+
+int
+iommu_unbind(struct pci_iommu_arena *arena, long pg_start, long pg_count)
+{
+	unsigned long *p;
+	long i;
+
+	if (!arena) return -EINVAL;
+
+	p = arena->ptes + pg_start;
+	for(i = 0; i < pg_count; i++)
+		p[i] = IOMMU_RESERVED_PTE;
+
+	return 0;
+}
+
+static int alpha_pci_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	return dma_addr == 0;
+}
+
+static int alpha_pci_set_mask(struct device *dev, u64 mask)
+{
+	if (!dev->dma_mask ||
+	    !pci_dma_supported(alpha_gendev_to_pci(dev), mask))
+		return -EIO;
+
+	*dev->dma_mask = mask;
+	return 0;
+}
+
+struct dma_map_ops alpha_pci_ops = {
+	.alloc			= alpha_pci_alloc_coherent,
+	.free			= alpha_pci_free_coherent,
+	.map_page		= alpha_pci_map_page,
+	.unmap_page		= alpha_pci_unmap_page,
+	.map_sg			= alpha_pci_map_sg,
+	.unmap_sg		= alpha_pci_unmap_sg,
+	.mapping_error		= alpha_pci_mapping_error,
+	.dma_supported		= alpha_pci_supported,
+	.set_dma_mask		= alpha_pci_set_mask,
+};
+
+struct dma_map_ops *dma_ops = &alpha_pci_ops;
+EXPORT_SYMBOL(dma_ops);