.. as it should have been from the time lib/swiotlb.c appeared.
As before, the patch works on 2.6.22 and was just made apply to the aged
Xen repository. It also depends on the make logic change submitted before.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Index: head-2007-07-10/arch/i386/kernel/swiotlb.c
===================================================================
--- head-2007-07-10.orig/arch/i386/kernel/swiotlb.c 2007-07-10
11:14:07.000000000 +0200
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,745 +0,0 @@
-/*
- * Dynamic DMA mapping support.
- *
- * This implementation is a fallback for platforms that do not support
- * I/O TLBs (aka DMA address translation hardware).
- * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@xxxxxxxxx>
- * Copyright (C) 2000 Goutham Rao <goutham.rao@xxxxxxxxx>
- * Copyright (C) 2000, 2003 Hewlett-Packard Co
- * David Mosberger-Tang <davidm@xxxxxxxxxx>
- * Copyright (C) 2005 Keir Fraser <keir@xxxxxxxxxxxxx>
- */
-
-#include <linux/cache.h>
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/pci.h>
-#include <linux/spinlock.h>
-#include <linux/string.h>
-#include <linux/types.h>
-#include <linux/ctype.h>
-#include <linux/init.h>
-#include <linux/bootmem.h>
-#include <linux/highmem.h>
-#include <asm/io.h>
-#include <asm/pci.h>
-#include <asm/dma.h>
-#include <asm/uaccess.h>
-#include <xen/gnttab.h>
-#include <xen/interface/memory.h>
-#include <asm-i386/mach-xen/asm/gnttab_dma.h>
-
-int swiotlb;
-EXPORT_SYMBOL(swiotlb);
-
-#define OFFSET(val,align) ((unsigned long)((val) & ( (align) - 1)))
-
-/*
- * Maximum allowable number of contiguous slabs to map,
- * must be a power of 2. What is the appropriate value ?
- * The complexity of {map,unmap}_single is linearly dependent on this value.
- */
-#define IO_TLB_SEGSIZE 128
-
-/*
- * log of the size of each IO TLB slab. The number of slabs is command line
- * controllable.
- */
-#define IO_TLB_SHIFT 11
-
-int swiotlb_force;
-
-static char *iotlb_virt_start;
-static unsigned long iotlb_nslabs;
-
-/*
- * Used to do a quick range check in swiotlb_unmap_single and
- * swiotlb_sync_single_*, to see if the memory was in fact allocated by this
- * API.
- */
-static unsigned long iotlb_pfn_start, iotlb_pfn_end;
-
-/* Does the given dma address reside within the swiotlb aperture? */
-static inline int in_swiotlb_aperture(dma_addr_t dev_addr)
-{
- unsigned long pfn = mfn_to_local_pfn(dev_addr >> PAGE_SHIFT);
- return (pfn_valid(pfn)
- && (pfn >= iotlb_pfn_start)
- && (pfn < iotlb_pfn_end));
-}
-
-/*
- * When the IOMMU overflows we return a fallback buffer. This sets the size.
- */
-static unsigned long io_tlb_overflow = 32*1024;
-
-void *io_tlb_overflow_buffer;
-
-/*
- * This is a free list describing the number of free entries available from
- * each index
- */
-static unsigned int *io_tlb_list;
-static unsigned int io_tlb_index;
-
-/*
- * We need to save away the original address corresponding to a mapped entry
- * for the sync operations.
- */
-static struct phys_addr {
- struct page *page;
- unsigned int offset;
-} *io_tlb_orig_addr;
-
-/*
- * Protect the above data structures in the map and unmap calls
- */
-static DEFINE_SPINLOCK(io_tlb_lock);
-
-static unsigned int dma_bits;
-static unsigned int __initdata max_dma_bits = 32;
-static int __init
-setup_dma_bits(char *str)
-{
- max_dma_bits = simple_strtoul(str, NULL, 0);
- return 0;
-}
-__setup("dma_bits=", setup_dma_bits);
-
-static int __init
-setup_io_tlb_npages(char *str)
-{
- /* Unlike ia64, the size is aperture in megabytes, not 'slabs'! */
- if (isdigit(*str)) {
- iotlb_nslabs = simple_strtoul(str, &str, 0) <<
- (20 - IO_TLB_SHIFT);
- iotlb_nslabs = ALIGN(iotlb_nslabs, IO_TLB_SEGSIZE);
- /* Round up to power of two (xen_create_contiguous_region). */
- while (iotlb_nslabs & (iotlb_nslabs-1))
- iotlb_nslabs += iotlb_nslabs & ~(iotlb_nslabs-1);
- }
- if (*str == ',')
- ++str;
- /*
- * NB. 'force' enables the swiotlb, but doesn't force its use for
- * every DMA like it does on native Linux. 'off' forcibly disables
- * use of the swiotlb.
- */
- if (!strcmp(str, "force"))
- swiotlb_force = 1;
- else if (!strcmp(str, "off"))
- swiotlb_force = -1;
- return 1;
-}
-__setup("swiotlb=", setup_io_tlb_npages);
-/* make io_tlb_overflow tunable too? */
-
-/*
- * Statically reserve bounce buffer space and initialize bounce buffer data
- * structures for the software IO TLB used to implement the PCI DMA API.
- */
-void
-swiotlb_init_with_default_size (size_t default_size)
-{
- unsigned long i, bytes;
- int rc;
-
- if (!iotlb_nslabs) {
- iotlb_nslabs = (default_size >> IO_TLB_SHIFT);
- iotlb_nslabs = ALIGN(iotlb_nslabs, IO_TLB_SEGSIZE);
- /* Round up to power of two (xen_create_contiguous_region). */
- while (iotlb_nslabs & (iotlb_nslabs-1))
- iotlb_nslabs += iotlb_nslabs & ~(iotlb_nslabs-1);
- }
-
- bytes = iotlb_nslabs * (1UL << IO_TLB_SHIFT);
-
- /*
- * Get IO TLB memory from the low pages
- */
- iotlb_virt_start = alloc_bootmem_low_pages(bytes);
- if (!iotlb_virt_start)
- panic("Cannot allocate SWIOTLB buffer!\n");
-
- dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
- for (i = 0; i < iotlb_nslabs; i += IO_TLB_SEGSIZE) {
- do {
- rc = xen_create_contiguous_region(
- (unsigned long)iotlb_virt_start + (i <<
IO_TLB_SHIFT),
- get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT),
- dma_bits);
- } while (rc && dma_bits++ < max_dma_bits);
- if (rc) {
- if (i == 0)
- panic("No suitable physical memory available
for SWIOTLB buffer!\n"
- "Use dom0_mem Xen boot parameter to
reserve\n"
- "some DMA memory (e.g.,
dom0_mem=-128M).\n");
- iotlb_nslabs = i;
- i <<= IO_TLB_SHIFT;
- free_bootmem(__pa(iotlb_virt_start + i), bytes - i);
- bytes = i;
- for (dma_bits = 0; i > 0; i -= IO_TLB_SEGSIZE <<
IO_TLB_SHIFT) {
- unsigned int bits =
fls64(virt_to_bus(iotlb_virt_start + i - 1));
-
- if (bits > dma_bits)
- dma_bits = bits;
- }
- break;
- }
- }
-
- /*
- * Allocate and initialize the free list array. This array is used
- * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE.
- */
- io_tlb_list = alloc_bootmem(iotlb_nslabs * sizeof(int));
- for (i = 0; i < iotlb_nslabs; i++)
- io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
- io_tlb_index = 0;
- io_tlb_orig_addr = alloc_bootmem(
- iotlb_nslabs * sizeof(*io_tlb_orig_addr));
-
- /*
- * Get the overflow emergency buffer
- */
- io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow);
- if (!io_tlb_overflow_buffer)
- panic("Cannot allocate SWIOTLB overflow buffer!\n");
-
- do {
- rc = xen_create_contiguous_region(
- (unsigned long)io_tlb_overflow_buffer,
- get_order(io_tlb_overflow),
- dma_bits);
- } while (rc && dma_bits++ < max_dma_bits);
- if (rc)
- panic("No suitable physical memory available for SWIOTLB
overflow buffer!\n");
-
- iotlb_pfn_start = __pa(iotlb_virt_start) >> PAGE_SHIFT;
- iotlb_pfn_end = iotlb_pfn_start + (bytes >> PAGE_SHIFT);
-
- printk(KERN_INFO "Software IO TLB enabled: \n"
- " Aperture: %lu megabytes\n"
- " Kernel range: %p - %p\n"
- " Address size: %u bits\n",
- bytes >> 20,
- iotlb_virt_start, iotlb_virt_start + bytes,
- dma_bits);
-}
-
-void
-swiotlb_init(void)
-{
- long ram_end;
- size_t defsz = 64 * (1 << 20); /* 64MB default size */
-
- if (swiotlb_force == 1) {
- swiotlb = 1;
- } else if ((swiotlb_force != -1) &&
- is_running_on_xen() &&
- is_initial_xendomain()) {
- /* Domain 0 always has a swiotlb. */
- ram_end = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
- if (ram_end <= 0x7ffff)
- defsz = 2 * (1 << 20); /* 2MB on <2GB on systems. */
- swiotlb = 1;
- }
-
- if (swiotlb)
- swiotlb_init_with_default_size(defsz);
- else
- printk(KERN_INFO "Software IO TLB disabled\n");
-}
-
-/*
- * We use __copy_to_user_inatomic to transfer to the host buffer because the
- * buffer may be mapped read-only (e.g, in blkback driver) but lower-level
- * drivers map the buffer for DMA_BIDIRECTIONAL access. This causes an
- * unnecessary copy from the aperture to the host buffer, and a page fault.
- */
-static void
-__sync_single(struct phys_addr buffer, char *dma_addr, size_t size, int dir)
-{
- if (PageHighMem(buffer.page)) {
- size_t len, bytes;
- char *dev, *host, *kmp;
- len = size;
- while (len != 0) {
- unsigned long flags;
-
- if (((bytes = len) + buffer.offset) > PAGE_SIZE)
- bytes = PAGE_SIZE - buffer.offset;
- local_irq_save(flags); /* protects KM_BOUNCE_READ */
- kmp = kmap_atomic(buffer.page, KM_BOUNCE_READ);
- dev = dma_addr + size - len;
- host = kmp + buffer.offset;
- if (dir == DMA_FROM_DEVICE) {
- if (__copy_to_user_inatomic(host, dev, bytes))
- /* inaccessible */;
- } else
- memcpy(dev, host, bytes);
- kunmap_atomic(kmp, KM_BOUNCE_READ);
- local_irq_restore(flags);
- len -= bytes;
- buffer.page++;
- buffer.offset = 0;
- }
- } else {
- char *host = (char *)phys_to_virt(
- page_to_pseudophys(buffer.page)) + buffer.offset;
- if (dir == DMA_FROM_DEVICE) {
- if (__copy_to_user_inatomic(host, dma_addr, size))
- /* inaccessible */;
- } else if (dir == DMA_TO_DEVICE)
- memcpy(dma_addr, host, size);
- }
-}
-
-/*
- * Allocates bounce buffer and returns its kernel virtual address.
- */
-static void *
-map_single(struct device *hwdev, struct phys_addr buffer, size_t size, int dir)
-{
- unsigned long flags;
- char *dma_addr;
- unsigned int nslots, stride, index, wrap;
- struct phys_addr slot_buf;
- int i;
-
- /*
- * For mappings greater than a page, we limit the stride (and
- * hence alignment) to a page size.
- */
- nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- if (size > PAGE_SIZE)
- stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
- else
- stride = 1;
-
- BUG_ON(!nslots);
-
- /*
- * Find suitable number of IO TLB entries size that will fit this
- * request and allocate a buffer from that IO TLB pool.
- */
- spin_lock_irqsave(&io_tlb_lock, flags);
- {
- wrap = index = ALIGN(io_tlb_index, stride);
-
- if (index >= iotlb_nslabs)
- wrap = index = 0;
-
- do {
- /*
- * If we find a slot that indicates we have 'nslots'
- * number of contiguous buffers, we allocate the
- * buffers from that slot and mark the entries as '0'
- * indicating unavailable.
- */
- if (io_tlb_list[index] >= nslots) {
- int count = 0;
-
- for (i = index; i < (int)(index + nslots); i++)
- io_tlb_list[i] = 0;
- for (i = index - 1;
- (OFFSET(i, IO_TLB_SEGSIZE) !=
- IO_TLB_SEGSIZE -1) && io_tlb_list[i];
- i--)
- io_tlb_list[i] = ++count;
- dma_addr = iotlb_virt_start +
- (index << IO_TLB_SHIFT);
-
- /*
- * Update the indices to avoid searching in
- * the next round.
- */
- io_tlb_index =
- ((index + nslots) < iotlb_nslabs
- ? (index + nslots) : 0);
-
- goto found;
- }
- index += stride;
- if (index >= iotlb_nslabs)
- index = 0;
- } while (index != wrap);
-
- spin_unlock_irqrestore(&io_tlb_lock, flags);
- return NULL;
- }
- found:
- spin_unlock_irqrestore(&io_tlb_lock, flags);
-
- /*
- * Save away the mapping from the original address to the DMA address.
- * This is needed when we sync the memory. Then we sync the buffer if
- * needed.
- */
- slot_buf = buffer;
- for (i = 0; i < nslots; i++) {
- slot_buf.page += slot_buf.offset >> PAGE_SHIFT;
- slot_buf.offset &= PAGE_SIZE - 1;
- io_tlb_orig_addr[index+i] = slot_buf;
- slot_buf.offset += 1 << IO_TLB_SHIFT;
- }
- if ((dir == DMA_TO_DEVICE) || (dir == DMA_BIDIRECTIONAL))
- __sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);
-
- return dma_addr;
-}
-
-struct phys_addr dma_addr_to_phys_addr(char *dma_addr)
-{
- int index = (dma_addr - iotlb_virt_start) >> IO_TLB_SHIFT;
- struct phys_addr buffer = io_tlb_orig_addr[index];
- buffer.offset += (long)dma_addr & ((1 << IO_TLB_SHIFT) - 1);
- buffer.page += buffer.offset >> PAGE_SHIFT;
- buffer.offset &= PAGE_SIZE - 1;
- return buffer;
-}
-
-/*
- * dma_addr is the kernel virtual address of the bounce buffer to unmap.
- */
-static void
-unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
-{
- unsigned long flags;
- int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- int index = (dma_addr - iotlb_virt_start) >> IO_TLB_SHIFT;
- struct phys_addr buffer = dma_addr_to_phys_addr(dma_addr);
-
- /*
- * First, sync the memory before unmapping the entry
- */
- if ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))
- __sync_single(buffer, dma_addr, size, DMA_FROM_DEVICE);
-
- /*
- * Return the buffer to the free list by setting the corresponding
- * entries to indicate the number of contigous entries available.
- * While returning the entries to the free list, we merge the entries
- * with slots below and above the pool being returned.
- */
- spin_lock_irqsave(&io_tlb_lock, flags);
- {
- count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
- io_tlb_list[index + nslots] : 0);
- /*
- * Step 1: return the slots to the free list, merging the
- * slots with superceeding slots
- */
- for (i = index + nslots - 1; i >= index; i--)
- io_tlb_list[i] = ++count;
- /*
- * Step 2: merge the returned slots with the preceding slots,
- * if available (non zero)
- */
- for (i = index - 1;
- (OFFSET(i, IO_TLB_SEGSIZE) !=
- IO_TLB_SEGSIZE -1) && io_tlb_list[i];
- i--)
- io_tlb_list[i] = ++count;
- }
- spin_unlock_irqrestore(&io_tlb_lock, flags);
-}
-
-static void
-sync_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
-{
- struct phys_addr buffer = dma_addr_to_phys_addr(dma_addr);
- BUG_ON((dir != DMA_FROM_DEVICE) && (dir != DMA_TO_DEVICE));
- __sync_single(buffer, dma_addr, size, dir);
-}
-
-static void
-swiotlb_full(struct device *dev, size_t size, int dir, int do_panic)
-{
- /*
- * Ran out of IOMMU space for this operation. This is very bad.
- * Unfortunately the drivers cannot handle this operation properly.
- * unless they check for pci_dma_mapping_error (most don't)
- * When the mapping is small enough return a static buffer to limit
- * the damage, or panic when the transfer is too big.
- */
- printk(KERN_ERR "PCI-DMA: Out of SW-IOMMU space for %lu bytes at "
- "device %s\n", (unsigned long)size, dev ? dev->bus_id : "?");
-
- if (size > io_tlb_overflow && do_panic) {
- 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("PCI-DMA: Random memory would be DMAed\n");
- }
-}
-
-/*
- * Map a single buffer of the indicated size for DMA in streaming mode. The
- * PCI address to use is returned.
- *
- * Once the device is given the dma address, the device owns this memory until
- * either swiotlb_unmap_single or swiotlb_dma_sync_single is performed.
- */
-dma_addr_t
-swiotlb_map_single(struct device *hwdev, void *ptr, size_t size, int dir)
-{
- dma_addr_t dev_addr = gnttab_dma_map_page(virt_to_page(ptr)) +
- offset_in_page(ptr);
- void *map;
- struct phys_addr buffer;
-
- BUG_ON(dir == DMA_NONE);
-
- /*
- * If the pointer passed in happens to be in the device's DMA window,
- * we can safely return the device addr and not worry about bounce
- * buffering it.
- */
- if (!range_straddles_page_boundary(__pa(ptr), size) &&
- !address_needs_mapping(hwdev, dev_addr))
- return dev_addr;
-
- /*
- * Oh well, have to allocate and map a bounce buffer.
- */
- gnttab_dma_unmap_page(dev_addr);
- buffer.page = virt_to_page(ptr);
- buffer.offset = (unsigned long)ptr & ~PAGE_MASK;
- map = map_single(hwdev, buffer, size, dir);
- if (!map) {
- swiotlb_full(hwdev, size, dir, 1);
- map = io_tlb_overflow_buffer;
- }
-
- dev_addr = virt_to_bus(map);
- return dev_addr;
-}
-
-/*
- * Unmap a single streaming mode DMA translation. The dma_addr and size must
- * match what was provided for in a previous swiotlb_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.
- */
-void
-swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr, size_t size,
- int dir)
-{
- BUG_ON(dir == DMA_NONE);
- if (in_swiotlb_aperture(dev_addr))
- unmap_single(hwdev, bus_to_virt(dev_addr), size, dir);
- else
- gnttab_dma_unmap_page(dev_addr);
-}
-
-/*
- * Make physical memory consistent for a single streaming mode DMA translation
- * after a transfer.
- *
- * If you perform a swiotlb_map_single() but wish to interrogate the buffer
- * using the cpu, yet do not wish to teardown the PCI dma mapping, you must
- * call this function before doing so. At the next point you give the PCI dma
- * address back to the card, you must first perform a
- * swiotlb_dma_sync_for_device, and then the device again owns the buffer
- */
-void
-swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
- size_t size, int dir)
-{
- BUG_ON(dir == DMA_NONE);
- if (in_swiotlb_aperture(dev_addr))
- sync_single(hwdev, bus_to_virt(dev_addr), size, dir);
-}
-
-void
-swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
- size_t size, int dir)
-{
- BUG_ON(dir == DMA_NONE);
- if (in_swiotlb_aperture(dev_addr))
- sync_single(hwdev, bus_to_virt(dev_addr), size, dir);
-}
-
-/*
- * Map a set of buffers described by scatterlist in streaming mode for DMA.
- * This is the scatter-gather version of the above swiotlb_map_single
- * interface. Here the scatter gather list elements are each tagged with the
- * appropriate dma address and length. They are obtained via
- * sg_dma_{address,length}(SG).
- *
- * NOTE: An implementation may be able to use a smaller number of
- * DMA address/length pairs than there are SG table elements.
- * (for example via virtual mapping capabilities)
- * The routine returns the number of addr/length pairs actually
- * used, at most nents.
- *
- * Device ownership issues as mentioned above for swiotlb_map_single are the
- * same here.
- */
-int
-swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
- int dir)
-{
- struct phys_addr buffer;
- dma_addr_t dev_addr;
- char *map;
- int i;
-
- BUG_ON(dir == DMA_NONE);
-
- for (i = 0; i < nelems; i++, sg++) {
- dev_addr = gnttab_dma_map_page(sg->page) + sg->offset;
-
- if (range_straddles_page_boundary(page_to_pseudophys(sg->page)
- + sg->offset, sg->length)
- || address_needs_mapping(hwdev, dev_addr)) {
- gnttab_dma_unmap_page(dev_addr);
- buffer.page = sg->page;
- buffer.offset = sg->offset;
- map = map_single(hwdev, buffer, sg->length, dir);
- if (!map) {
- /* Don't panic here, we expect map_sg users
- to do proper error handling. */
- swiotlb_full(hwdev, sg->length, dir, 0);
- swiotlb_unmap_sg(hwdev, sg - i, i, dir);
- sg[0].dma_length = 0;
- return 0;
- }
- sg->dma_address = (dma_addr_t)virt_to_bus(map);
- } else
- sg->dma_address = dev_addr;
- sg->dma_length = sg->length;
- }
- return nelems;
-}
-
-/*
- * Unmap a set of streaming mode DMA translations. Again, cpu read rules
- * concerning calls here are the same as for swiotlb_unmap_single() above.
- */
-void
-swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
- int dir)
-{
- int i;
-
- BUG_ON(dir == DMA_NONE);
-
- for (i = 0; i < nelems; i++, sg++)
- if (in_swiotlb_aperture(sg->dma_address))
- unmap_single(hwdev,
- (void *)bus_to_virt(sg->dma_address),
- sg->dma_length, dir);
- else
- gnttab_dma_unmap_page(sg->dma_address);
-}
-
-/*
- * Make physical memory consistent for a set of streaming mode DMA translations
- * after a transfer.
- *
- * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
- * and usage.
- */
-void
-swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
- int nelems, int dir)
-{
- int i;
-
- BUG_ON(dir == DMA_NONE);
-
- for (i = 0; i < nelems; i++, sg++)
- if (in_swiotlb_aperture(sg->dma_address))
- sync_single(hwdev,
- (void *)bus_to_virt(sg->dma_address),
- sg->dma_length, dir);
-}
-
-void
-swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
- int nelems, int dir)
-{
- int i;
-
- BUG_ON(dir == DMA_NONE);
-
- for (i = 0; i < nelems; i++, sg++)
- if (in_swiotlb_aperture(sg->dma_address))
- sync_single(hwdev,
- (void *)bus_to_virt(sg->dma_address),
- sg->dma_length, dir);
-}
-
-#ifdef CONFIG_HIGHMEM
-
-dma_addr_t
-swiotlb_map_page(struct device *hwdev, struct page *page,
- unsigned long offset, size_t size,
- enum dma_data_direction direction)
-{
- struct phys_addr buffer;
- dma_addr_t dev_addr;
- char *map;
-
- dev_addr = gnttab_dma_map_page(page) + offset;
- if (address_needs_mapping(hwdev, dev_addr)) {
- gnttab_dma_unmap_page(dev_addr);
- buffer.page = page;
- buffer.offset = offset;
- map = map_single(hwdev, buffer, size, direction);
- if (!map) {
- swiotlb_full(hwdev, size, direction, 1);
- map = io_tlb_overflow_buffer;
- }
- dev_addr = (dma_addr_t)virt_to_bus(map);
- }
-
- return dev_addr;
-}
-
-void
-swiotlb_unmap_page(struct device *hwdev, dma_addr_t dma_address,
- size_t size, enum dma_data_direction direction)
-{
- BUG_ON(direction == DMA_NONE);
- if (in_swiotlb_aperture(dma_address))
- unmap_single(hwdev, bus_to_virt(dma_address), size, direction);
- else
- gnttab_dma_unmap_page(dma_address);
-}
-
-#endif
-
-int
-swiotlb_dma_mapping_error(dma_addr_t dma_addr)
-{
- return (dma_addr == virt_to_bus(io_tlb_overflow_buffer));
-}
-
-/*
- * Return whether the given PCI device DMA address mask can be supported
- * properly. For example, if your device can only drive the low 24-bits
- * during PCI bus mastering, then you would pass 0x00ffffff as the mask to
- * this function.
- */
-int
-swiotlb_dma_supported (struct device *hwdev, u64 mask)
-{
- return (mask >= ((1UL << dma_bits) - 1));
-}
-
-EXPORT_SYMBOL(swiotlb_init);
-EXPORT_SYMBOL(swiotlb_map_single);
-EXPORT_SYMBOL(swiotlb_unmap_single);
-EXPORT_SYMBOL(swiotlb_map_sg);
-EXPORT_SYMBOL(swiotlb_unmap_sg);
-EXPORT_SYMBOL(swiotlb_sync_single_for_cpu);
-EXPORT_SYMBOL(swiotlb_sync_single_for_device);
-EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
-EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
-EXPORT_SYMBOL(swiotlb_dma_mapping_error);
-EXPORT_SYMBOL(swiotlb_dma_supported);
Index: head-2007-07-10/lib/Makefile
===================================================================
--- head-2007-07-10.orig/lib/Makefile 2007-07-10 10:29:24.000000000 +0200
+++ head-2007-07-10/lib/Makefile 2007-07-10 11:20:35.000000000 +0200
@@ -58,9 +58,6 @@ obj-$(CONFIG_SMP) += percpu_counter.o
obj-$(CONFIG_AUDIT_GENERIC) += audit.o
obj-$(CONFIG_SWIOTLB) += swiotlb.o
-ifeq ($(CONFIG_X86),y)
-swiotlb-$(CONFIG_XEN) := ../arch/i386/kernel/swiotlb.o
-endif
ifeq ($(CONFIG_IA64),y)
swiotlb-$(CONFIG_XEN) := ../arch/ia64/xen/swiotlb.o
endif
Index: head-2007-07-10/lib/swiotlb-xen.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ head-2007-07-10/lib/swiotlb-xen.c 2007-07-10 11:20:35.000000000 +0200
@@ -0,0 +1,745 @@
+/*
+ * Dynamic DMA mapping support.
+ *
+ * This implementation is a fallback for platforms that do not support
+ * I/O TLBs (aka DMA address translation hardware).
+ * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@xxxxxxxxx>
+ * Copyright (C) 2000 Goutham Rao <goutham.rao@xxxxxxxxx>
+ * Copyright (C) 2000, 2003 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@xxxxxxxxxx>
+ * Copyright (C) 2005 Keir Fraser <keir@xxxxxxxxxxxxx>
+ */
+
+#include <linux/cache.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <asm/io.h>
+#include <asm/pci.h>
+#include <asm/dma.h>
+#include <asm/uaccess.h>
+#include <xen/gnttab.h>
+#include <xen/interface/memory.h>
+#include <asm-i386/mach-xen/asm/gnttab_dma.h>
+
+int swiotlb;
+EXPORT_SYMBOL(swiotlb);
+
+#define OFFSET(val,align) ((unsigned long)((val) & ( (align) - 1)))
+
+/*
+ * Maximum allowable number of contiguous slabs to map,
+ * must be a power of 2. What is the appropriate value ?
+ * The complexity of {map,unmap}_single is linearly dependent on this value.
+ */
+#define IO_TLB_SEGSIZE 128
+
+/*
+ * log of the size of each IO TLB slab. The number of slabs is command line
+ * controllable.
+ */
+#define IO_TLB_SHIFT 11
+
+int swiotlb_force;
+
+static char *iotlb_virt_start;
+static unsigned long iotlb_nslabs;
+
+/*
+ * Used to do a quick range check in swiotlb_unmap_single and
+ * swiotlb_sync_single_*, to see if the memory was in fact allocated by this
+ * API.
+ */
+static unsigned long iotlb_pfn_start, iotlb_pfn_end;
+
+/* Does the given dma address reside within the swiotlb aperture? */
+static inline int in_swiotlb_aperture(dma_addr_t dev_addr)
+{
+ unsigned long pfn = mfn_to_local_pfn(dev_addr >> PAGE_SHIFT);
+ return (pfn_valid(pfn)
+ && (pfn >= iotlb_pfn_start)
+ && (pfn < iotlb_pfn_end));
+}
+
+/*
+ * When the IOMMU overflows we return a fallback buffer. This sets the size.
+ */
+static unsigned long io_tlb_overflow = 32*1024;
+
+void *io_tlb_overflow_buffer;
+
+/*
+ * This is a free list describing the number of free entries available from
+ * each index
+ */
+static unsigned int *io_tlb_list;
+static unsigned int io_tlb_index;
+
+/*
+ * We need to save away the original address corresponding to a mapped entry
+ * for the sync operations.
+ */
+static struct phys_addr {
+ struct page *page;
+ unsigned int offset;
+} *io_tlb_orig_addr;
+
+/*
+ * Protect the above data structures in the map and unmap calls
+ */
+static DEFINE_SPINLOCK(io_tlb_lock);
+
+static unsigned int dma_bits;
+static unsigned int __initdata max_dma_bits = 32;
+static int __init
+setup_dma_bits(char *str)
+{
+ max_dma_bits = simple_strtoul(str, NULL, 0);
+ return 0;
+}
+__setup("dma_bits=", setup_dma_bits);
+
+static int __init
+setup_io_tlb_npages(char *str)
+{
+ /* Unlike ia64, the size is aperture in megabytes, not 'slabs'! */
+ if (isdigit(*str)) {
+ iotlb_nslabs = simple_strtoul(str, &str, 0) <<
+ (20 - IO_TLB_SHIFT);
+ iotlb_nslabs = ALIGN(iotlb_nslabs, IO_TLB_SEGSIZE);
+ /* Round up to power of two (xen_create_contiguous_region). */
+ while (iotlb_nslabs & (iotlb_nslabs-1))
+ iotlb_nslabs += iotlb_nslabs & ~(iotlb_nslabs-1);
+ }
+ if (*str == ',')
+ ++str;
+ /*
+ * NB. 'force' enables the swiotlb, but doesn't force its use for
+ * every DMA like it does on native Linux. 'off' forcibly disables
+ * use of the swiotlb.
+ */
+ if (!strcmp(str, "force"))
+ swiotlb_force = 1;
+ else if (!strcmp(str, "off"))
+ swiotlb_force = -1;
+ return 1;
+}
+__setup("swiotlb=", setup_io_tlb_npages);
+/* make io_tlb_overflow tunable too? */
+
+/*
+ * Statically reserve bounce buffer space and initialize bounce buffer data
+ * structures for the software IO TLB used to implement the PCI DMA API.
+ */
+void
+swiotlb_init_with_default_size (size_t default_size)
+{
+ unsigned long i, bytes;
+ int rc;
+
+ if (!iotlb_nslabs) {
+ iotlb_nslabs = (default_size >> IO_TLB_SHIFT);
+ iotlb_nslabs = ALIGN(iotlb_nslabs, IO_TLB_SEGSIZE);
+ /* Round up to power of two (xen_create_contiguous_region). */
+ while (iotlb_nslabs & (iotlb_nslabs-1))
+ iotlb_nslabs += iotlb_nslabs & ~(iotlb_nslabs-1);
+ }
+
+ bytes = iotlb_nslabs * (1UL << IO_TLB_SHIFT);
+
+ /*
+ * Get IO TLB memory from the low pages
+ */
+ iotlb_virt_start = alloc_bootmem_low_pages(bytes);
+ if (!iotlb_virt_start)
+ panic("Cannot allocate SWIOTLB buffer!\n");
+
+ dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
+ for (i = 0; i < iotlb_nslabs; i += IO_TLB_SEGSIZE) {
+ do {
+ rc = xen_create_contiguous_region(
+ (unsigned long)iotlb_virt_start + (i <<
IO_TLB_SHIFT),
+ get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT),
+ dma_bits);
+ } while (rc && dma_bits++ < max_dma_bits);
+ if (rc) {
+ if (i == 0)
+ panic("No suitable physical memory available
for SWIOTLB buffer!\n"
+ "Use dom0_mem Xen boot parameter to
reserve\n"
+ "some DMA memory (e.g.,
dom0_mem=-128M).\n");
+ iotlb_nslabs = i;
+ i <<= IO_TLB_SHIFT;
+ free_bootmem(__pa(iotlb_virt_start + i), bytes - i);
+ bytes = i;
+ for (dma_bits = 0; i > 0; i -= IO_TLB_SEGSIZE <<
IO_TLB_SHIFT) {
+ unsigned int bits =
fls64(virt_to_bus(iotlb_virt_start + i - 1));
+
+ if (bits > dma_bits)
+ dma_bits = bits;
+ }
+ break;
+ }
+ }
+
+ /*
+ * Allocate and initialize the free list array. This array is used
+ * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE.
+ */
+ io_tlb_list = alloc_bootmem(iotlb_nslabs * sizeof(int));
+ for (i = 0; i < iotlb_nslabs; i++)
+ io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_index = 0;
+ io_tlb_orig_addr = alloc_bootmem(
+ iotlb_nslabs * sizeof(*io_tlb_orig_addr));
+
+ /*
+ * Get the overflow emergency buffer
+ */
+ io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow);
+ if (!io_tlb_overflow_buffer)
+ panic("Cannot allocate SWIOTLB overflow buffer!\n");
+
+ do {
+ rc = xen_create_contiguous_region(
+ (unsigned long)io_tlb_overflow_buffer,
+ get_order(io_tlb_overflow),
+ dma_bits);
+ } while (rc && dma_bits++ < max_dma_bits);
+ if (rc)
+ panic("No suitable physical memory available for SWIOTLB
overflow buffer!\n");
+
+ iotlb_pfn_start = __pa(iotlb_virt_start) >> PAGE_SHIFT;
+ iotlb_pfn_end = iotlb_pfn_start + (bytes >> PAGE_SHIFT);
+
+ printk(KERN_INFO "Software IO TLB enabled: \n"
+ " Aperture: %lu megabytes\n"
+ " Kernel range: %p - %p\n"
+ " Address size: %u bits\n",
+ bytes >> 20,
+ iotlb_virt_start, iotlb_virt_start + bytes,
+ dma_bits);
+}
+
+void
+swiotlb_init(void)
+{
+ long ram_end;
+ size_t defsz = 64 * (1 << 20); /* 64MB default size */
+
+ if (swiotlb_force == 1) {
+ swiotlb = 1;
+ } else if ((swiotlb_force != -1) &&
+ is_running_on_xen() &&
+ is_initial_xendomain()) {
+ /* Domain 0 always has a swiotlb. */
+ ram_end = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
+ if (ram_end <= 0x7ffff)
+ defsz = 2 * (1 << 20); /* 2MB on <2GB on systems. */
+ swiotlb = 1;
+ }
+
+ if (swiotlb)
+ swiotlb_init_with_default_size(defsz);
+ else
+ printk(KERN_INFO "Software IO TLB disabled\n");
+}
+
+/*
+ * We use __copy_to_user_inatomic to transfer to the host buffer because the
+ * buffer may be mapped read-only (e.g, in blkback driver) but lower-level
+ * drivers map the buffer for DMA_BIDIRECTIONAL access. This causes an
+ * unnecessary copy from the aperture to the host buffer, and a page fault.
+ */
+static void
+__sync_single(struct phys_addr buffer, char *dma_addr, size_t size, int dir)
+{
+ if (PageHighMem(buffer.page)) {
+ size_t len, bytes;
+ char *dev, *host, *kmp;
+ len = size;
+ while (len != 0) {
+ unsigned long flags;
+
+ if (((bytes = len) + buffer.offset) > PAGE_SIZE)
+ bytes = PAGE_SIZE - buffer.offset;
+ local_irq_save(flags); /* protects KM_BOUNCE_READ */
+ kmp = kmap_atomic(buffer.page, KM_BOUNCE_READ);
+ dev = dma_addr + size - len;
+ host = kmp + buffer.offset;
+ if (dir == DMA_FROM_DEVICE) {
+ if (__copy_to_user_inatomic(host, dev, bytes))
+ /* inaccessible */;
+ } else
+ memcpy(dev, host, bytes);
+ kunmap_atomic(kmp, KM_BOUNCE_READ);
+ local_irq_restore(flags);
+ len -= bytes;
+ buffer.page++;
+ buffer.offset = 0;
+ }
+ } else {
+ char *host = (char *)phys_to_virt(
+ page_to_pseudophys(buffer.page)) + buffer.offset;
+ if (dir == DMA_FROM_DEVICE) {
+ if (__copy_to_user_inatomic(host, dma_addr, size))
+ /* inaccessible */;
+ } else if (dir == DMA_TO_DEVICE)
+ memcpy(dma_addr, host, size);
+ }
+}
+
+/*
+ * Allocates bounce buffer and returns its kernel virtual address.
+ */
+static void *
+map_single(struct device *hwdev, struct phys_addr buffer, size_t size, int dir)
+{
+ unsigned long flags;
+ char *dma_addr;
+ unsigned int nslots, stride, index, wrap;
+ struct phys_addr slot_buf;
+ int i;
+
+ /*
+ * For mappings greater than a page, we limit the stride (and
+ * hence alignment) to a page size.
+ */
+ nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ if (size > PAGE_SIZE)
+ stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
+ else
+ stride = 1;
+
+ BUG_ON(!nslots);
+
+ /*
+ * Find suitable number of IO TLB entries size that will fit this
+ * request and allocate a buffer from that IO TLB pool.
+ */
+ spin_lock_irqsave(&io_tlb_lock, flags);
+ {
+ wrap = index = ALIGN(io_tlb_index, stride);
+
+ if (index >= iotlb_nslabs)
+ wrap = index = 0;
+
+ do {
+ /*
+ * If we find a slot that indicates we have 'nslots'
+ * number of contiguous buffers, we allocate the
+ * buffers from that slot and mark the entries as '0'
+ * indicating unavailable.
+ */
+ if (io_tlb_list[index] >= nslots) {
+ int count = 0;
+
+ for (i = index; i < (int)(index + nslots); i++)
+ io_tlb_list[i] = 0;
+ for (i = index - 1;
+ (OFFSET(i, IO_TLB_SEGSIZE) !=
+ IO_TLB_SEGSIZE -1) && io_tlb_list[i];
+ i--)
+ io_tlb_list[i] = ++count;
+ dma_addr = iotlb_virt_start +
+ (index << IO_TLB_SHIFT);
+
+ /*
+ * Update the indices to avoid searching in
+ * the next round.
+ */
+ io_tlb_index =
+ ((index + nslots) < iotlb_nslabs
+ ? (index + nslots) : 0);
+
+ goto found;
+ }
+ index += stride;
+ if (index >= iotlb_nslabs)
+ index = 0;
+ } while (index != wrap);
+
+ spin_unlock_irqrestore(&io_tlb_lock, flags);
+ return NULL;
+ }
+ found:
+ spin_unlock_irqrestore(&io_tlb_lock, flags);
+
+ /*
+ * Save away the mapping from the original address to the DMA address.
+ * This is needed when we sync the memory. Then we sync the buffer if
+ * needed.
+ */
+ slot_buf = buffer;
+ for (i = 0; i < nslots; i++) {
+ slot_buf.page += slot_buf.offset >> PAGE_SHIFT;
+ slot_buf.offset &= PAGE_SIZE - 1;
+ io_tlb_orig_addr[index+i] = slot_buf;
+ slot_buf.offset += 1 << IO_TLB_SHIFT;
+ }
+ if ((dir == DMA_TO_DEVICE) || (dir == DMA_BIDIRECTIONAL))
+ __sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);
+
+ return dma_addr;
+}
+
+struct phys_addr dma_addr_to_phys_addr(char *dma_addr)
+{
+ int index = (dma_addr - iotlb_virt_start) >> IO_TLB_SHIFT;
+ struct phys_addr buffer = io_tlb_orig_addr[index];
+ buffer.offset += (long)dma_addr & ((1 << IO_TLB_SHIFT) - 1);
+ buffer.page += buffer.offset >> PAGE_SHIFT;
+ buffer.offset &= PAGE_SIZE - 1;
+ return buffer;
+}
+
+/*
+ * dma_addr is the kernel virtual address of the bounce buffer to unmap.
+ */
+static void
+unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
+{
+ unsigned long flags;
+ int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ int index = (dma_addr - iotlb_virt_start) >> IO_TLB_SHIFT;
+ struct phys_addr buffer = dma_addr_to_phys_addr(dma_addr);
+
+ /*
+ * First, sync the memory before unmapping the entry
+ */
+ if ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))
+ __sync_single(buffer, dma_addr, size, DMA_FROM_DEVICE);
+
+ /*
+ * Return the buffer to the free list by setting the corresponding
+ * entries to indicate the number of contigous entries available.
+ * While returning the entries to the free list, we merge the entries
+ * with slots below and above the pool being returned.
+ */
+ spin_lock_irqsave(&io_tlb_lock, flags);
+ {
+ count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
+ io_tlb_list[index + nslots] : 0);
+ /*
+ * Step 1: return the slots to the free list, merging the
+ * slots with superceeding slots
+ */
+ for (i = index + nslots - 1; i >= index; i--)
+ io_tlb_list[i] = ++count;
+ /*
+ * Step 2: merge the returned slots with the preceding slots,
+ * if available (non zero)
+ */
+ for (i = index - 1;
+ (OFFSET(i, IO_TLB_SEGSIZE) !=
+ IO_TLB_SEGSIZE -1) && io_tlb_list[i];
+ i--)
+ io_tlb_list[i] = ++count;
+ }
+ spin_unlock_irqrestore(&io_tlb_lock, flags);
+}
+
+static void
+sync_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
+{
+ struct phys_addr buffer = dma_addr_to_phys_addr(dma_addr);
+ BUG_ON((dir != DMA_FROM_DEVICE) && (dir != DMA_TO_DEVICE));
+ __sync_single(buffer, dma_addr, size, dir);
+}
+
+static void
+swiotlb_full(struct device *dev, size_t size, int dir, int do_panic)
+{
+ /*
+ * Ran out of IOMMU space for this operation. This is very bad.
+ * Unfortunately the drivers cannot handle this operation properly.
+ * unless they check for pci_dma_mapping_error (most don't)
+ * When the mapping is small enough return a static buffer to limit
+ * the damage, or panic when the transfer is too big.
+ */
+ printk(KERN_ERR "PCI-DMA: Out of SW-IOMMU space for %lu bytes at "
+ "device %s\n", (unsigned long)size, dev ? dev->bus_id : "?");
+
+ if (size > io_tlb_overflow && do_panic) {
+ 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("PCI-DMA: Random memory would be DMAed\n");
+ }
+}
+
+/*
+ * Map a single buffer of the indicated size for DMA in streaming mode. The
+ * PCI address to use is returned.
+ *
+ * Once the device is given the dma address, the device owns this memory until
+ * either swiotlb_unmap_single or swiotlb_dma_sync_single is performed.
+ */
+dma_addr_t
+swiotlb_map_single(struct device *hwdev, void *ptr, size_t size, int dir)
+{
+ dma_addr_t dev_addr = gnttab_dma_map_page(virt_to_page(ptr)) +
+ offset_in_page(ptr);
+ void *map;
+ struct phys_addr buffer;
+
+ BUG_ON(dir == DMA_NONE);
+
+ /*
+ * If the pointer passed in happens to be in the device's DMA window,
+ * we can safely return the device addr and not worry about bounce
+ * buffering it.
+ */
+ if (!range_straddles_page_boundary(__pa(ptr), size) &&
+ !address_needs_mapping(hwdev, dev_addr))
+ return dev_addr;
+
+ /*
+ * Oh well, have to allocate and map a bounce buffer.
+ */
+ gnttab_dma_unmap_page(dev_addr);
+ buffer.page = virt_to_page(ptr);
+ buffer.offset = (unsigned long)ptr & ~PAGE_MASK;
+ map = map_single(hwdev, buffer, size, dir);
+ if (!map) {
+ swiotlb_full(hwdev, size, dir, 1);
+ map = io_tlb_overflow_buffer;
+ }
+
+ dev_addr = virt_to_bus(map);
+ return dev_addr;
+}
+
+/*
+ * Unmap a single streaming mode DMA translation. The dma_addr and size must
+ * match what was provided for in a previous swiotlb_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.
+ */
+void
+swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr, size_t size,
+ int dir)
+{
+ BUG_ON(dir == DMA_NONE);
+ if (in_swiotlb_aperture(dev_addr))
+ unmap_single(hwdev, bus_to_virt(dev_addr), size, dir);
+ else
+ gnttab_dma_unmap_page(dev_addr);
+}
+
+/*
+ * Make physical memory consistent for a single streaming mode DMA translation
+ * after a transfer.
+ *
+ * If you perform a swiotlb_map_single() but wish to interrogate the buffer
+ * using the cpu, yet do not wish to teardown the PCI dma mapping, you must
+ * call this function before doing so. At the next point you give the PCI dma
+ * address back to the card, you must first perform a
+ * swiotlb_dma_sync_for_device, and then the device again owns the buffer
+ */
+void
+swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, int dir)
+{
+ BUG_ON(dir == DMA_NONE);
+ if (in_swiotlb_aperture(dev_addr))
+ sync_single(hwdev, bus_to_virt(dev_addr), size, dir);
+}
+
+void
+swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, int dir)
+{
+ BUG_ON(dir == DMA_NONE);
+ if (in_swiotlb_aperture(dev_addr))
+ sync_single(hwdev, bus_to_virt(dev_addr), size, dir);
+}
+
+/*
+ * Map a set of buffers described by scatterlist in streaming mode for DMA.
+ * This is the scatter-gather version of the above swiotlb_map_single
+ * interface. Here the scatter gather list elements are each tagged with the
+ * appropriate dma address and length. They are obtained via
+ * sg_dma_{address,length}(SG).
+ *
+ * NOTE: An implementation may be able to use a smaller number of
+ * DMA address/length pairs than there are SG table elements.
+ * (for example via virtual mapping capabilities)
+ * The routine returns the number of addr/length pairs actually
+ * used, at most nents.
+ *
+ * Device ownership issues as mentioned above for swiotlb_map_single are the
+ * same here.
+ */
+int
+swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
+ int dir)
+{
+ struct phys_addr buffer;
+ dma_addr_t dev_addr;
+ char *map;
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for (i = 0; i < nelems; i++, sg++) {
+ dev_addr = gnttab_dma_map_page(sg->page) + sg->offset;
+
+ if (range_straddles_page_boundary(page_to_pseudophys(sg->page)
+ + sg->offset, sg->length)
+ || address_needs_mapping(hwdev, dev_addr)) {
+ gnttab_dma_unmap_page(dev_addr);
+ buffer.page = sg->page;
+ buffer.offset = sg->offset;
+ map = map_single(hwdev, buffer, sg->length, dir);
+ if (!map) {
+ /* Don't panic here, we expect map_sg users
+ to do proper error handling. */
+ swiotlb_full(hwdev, sg->length, dir, 0);
+ swiotlb_unmap_sg(hwdev, sg - i, i, dir);
+ sg[0].dma_length = 0;
+ return 0;
+ }
+ sg->dma_address = (dma_addr_t)virt_to_bus(map);
+ } else
+ sg->dma_address = dev_addr;
+ sg->dma_length = sg->length;
+ }
+ return nelems;
+}
+
+/*
+ * Unmap a set of streaming mode DMA translations. Again, cpu read rules
+ * concerning calls here are the same as for swiotlb_unmap_single() above.
+ */
+void
+swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
+ int dir)
+{
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for (i = 0; i < nelems; i++, sg++)
+ if (in_swiotlb_aperture(sg->dma_address))
+ unmap_single(hwdev,
+ (void *)bus_to_virt(sg->dma_address),
+ sg->dma_length, dir);
+ else
+ gnttab_dma_unmap_page(sg->dma_address);
+}
+
+/*
+ * Make physical memory consistent for a set of streaming mode DMA translations
+ * after a transfer.
+ *
+ * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
+ * and usage.
+ */
+void
+swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
+ int nelems, int dir)
+{
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for (i = 0; i < nelems; i++, sg++)
+ if (in_swiotlb_aperture(sg->dma_address))
+ sync_single(hwdev,
+ (void *)bus_to_virt(sg->dma_address),
+ sg->dma_length, dir);
+}
+
+void
+swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
+ int nelems, int dir)
+{
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for (i = 0; i < nelems; i++, sg++)
+ if (in_swiotlb_aperture(sg->dma_address))
+ sync_single(hwdev,
+ (void *)bus_to_virt(sg->dma_address),
+ sg->dma_length, dir);
+}
+
+#ifdef CONFIG_HIGHMEM
+
+dma_addr_t
+swiotlb_map_page(struct device *hwdev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction direction)
+{
+ struct phys_addr buffer;
+ dma_addr_t dev_addr;
+ char *map;
+
+ dev_addr = gnttab_dma_map_page(page) + offset;
+ if (address_needs_mapping(hwdev, dev_addr)) {
+ gnttab_dma_unmap_page(dev_addr);
+ buffer.page = page;
+ buffer.offset = offset;
+ map = map_single(hwdev, buffer, size, direction);
+ if (!map) {
+ swiotlb_full(hwdev, size, direction, 1);
+ map = io_tlb_overflow_buffer;
+ }
+ dev_addr = (dma_addr_t)virt_to_bus(map);
+ }
+
+ return dev_addr;
+}
+
+void
+swiotlb_unmap_page(struct device *hwdev, dma_addr_t dma_address,
+ size_t size, enum dma_data_direction direction)
+{
+ BUG_ON(direction == DMA_NONE);
+ if (in_swiotlb_aperture(dma_address))
+ unmap_single(hwdev, bus_to_virt(dma_address), size, direction);
+ else
+ gnttab_dma_unmap_page(dma_address);
+}
+
+#endif
+
+int
+swiotlb_dma_mapping_error(dma_addr_t dma_addr)
+{
+ return (dma_addr == virt_to_bus(io_tlb_overflow_buffer));
+}
+
+/*
+ * Return whether the given PCI device DMA address mask can be supported
+ * properly. For example, if your device can only drive the low 24-bits
+ * during PCI bus mastering, then you would pass 0x00ffffff as the mask to
+ * this function.
+ */
+int
+swiotlb_dma_supported (struct device *hwdev, u64 mask)
+{
+ return (mask >= ((1UL << dma_bits) - 1));
+}
+
+EXPORT_SYMBOL(swiotlb_init);
+EXPORT_SYMBOL(swiotlb_map_single);
+EXPORT_SYMBOL(swiotlb_unmap_single);
+EXPORT_SYMBOL(swiotlb_map_sg);
+EXPORT_SYMBOL(swiotlb_unmap_sg);
+EXPORT_SYMBOL(swiotlb_sync_single_for_cpu);
+EXPORT_SYMBOL(swiotlb_sync_single_for_device);
+EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
+EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
+EXPORT_SYMBOL(swiotlb_dma_mapping_error);
+EXPORT_SYMBOL(swiotlb_dma_supported);
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