Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/arch/ia64/lib/swiotlb.c b/arch/ia64/lib/swiotlb.c
new file mode 100644
index 0000000..ab7b3ad
--- /dev/null
+++ b/arch/ia64/lib/swiotlb.c
@@ -0,0 +1,658 @@
+/*
+ * Dynamic DMA mapping support.
+ *
+ * This implementation is for IA-64 platforms that do not support
+ * I/O TLBs (aka DMA address translation hardware).
+ * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
+ * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
+ * Copyright (C) 2000, 2003 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * 03/05/07 davidm Switch from PCI-DMA to generic device DMA API.
+ * 00/12/13 davidm Rename to swiotlb.c and add mark_clean() to avoid
+ * unnecessary i-cache flushing.
+ * 04/07/.. ak Better overflow handling. Assorted fixes.
+ */
+
+#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 <asm/io.h>
+#include <asm/pci.h>
+#include <asm/dma.h>
+
+#include <linux/init.h>
+#include <linux/bootmem.h>
+
+#define OFFSET(val,align) ((unsigned long) \
+ ( (val) & ( (align) - 1)))
+
+#define SG_ENT_VIRT_ADDRESS(sg) (page_address((sg)->page) + (sg)->offset)
+#define SG_ENT_PHYS_ADDRESS(SG) virt_to_phys(SG_ENT_VIRT_ADDRESS(SG))
+
+/*
+ * 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;
+
+/*
+ * 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 char *io_tlb_start, *io_tlb_end;
+
+/*
+ * The number of IO TLB blocks (in groups of 64) betweeen io_tlb_start and
+ * io_tlb_end. This is command line adjustable via setup_io_tlb_npages.
+ */
+static unsigned long io_tlb_nslabs;
+
+/*
+ * 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 unsigned char **io_tlb_orig_addr;
+
+/*
+ * Protect the above data structures in the map and unmap calls
+ */
+static DEFINE_SPINLOCK(io_tlb_lock);
+
+static int __init
+setup_io_tlb_npages(char *str)
+{
+ if (isdigit(*str)) {
+ io_tlb_nslabs = simple_strtoul(str, &str, 0) <<
+ (PAGE_SHIFT - IO_TLB_SHIFT);
+ /* avoid tail segment of size < IO_TLB_SEGSIZE */
+ io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ }
+ if (*str == ',')
+ ++str;
+ if (!strcmp(str, "force"))
+ 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;
+
+ if (!io_tlb_nslabs) {
+ io_tlb_nslabs = (default_size >> PAGE_SHIFT);
+ io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ }
+
+ /*
+ * Get IO TLB memory from the low pages
+ */
+ io_tlb_start = alloc_bootmem_low_pages(io_tlb_nslabs *
+ (1 << IO_TLB_SHIFT));
+ if (!io_tlb_start)
+ panic("Cannot allocate SWIOTLB buffer");
+ io_tlb_end = io_tlb_start + io_tlb_nslabs * (1 << IO_TLB_SHIFT);
+
+ /*
+ * Allocate and initialize the free list array. This array is used
+ * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
+ * between io_tlb_start and io_tlb_end.
+ */
+ io_tlb_list = alloc_bootmem(io_tlb_nslabs * sizeof(int));
+ for (i = 0; i < io_tlb_nslabs; i++)
+ io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_index = 0;
+ io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *));
+
+ /*
+ * Get the overflow emergency buffer
+ */
+ io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow);
+ printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n",
+ virt_to_phys(io_tlb_start), virt_to_phys(io_tlb_end));
+}
+
+void
+swiotlb_init (void)
+{
+ swiotlb_init_with_default_size(64 * (1<<20)); /* default to 64MB */
+}
+
+static inline int
+address_needs_mapping(struct device *hwdev, dma_addr_t addr)
+{
+ dma_addr_t mask = 0xffffffff;
+ /* If the device has a mask, use it, otherwise default to 32 bits */
+ if (hwdev && hwdev->dma_mask)
+ mask = *hwdev->dma_mask;
+ return (addr & ~mask) != 0;
+}
+
+/*
+ * Allocates bounce buffer and returns its kernel virtual address.
+ */
+static void *
+map_single(struct device *hwdev, char *buffer, size_t size, int dir)
+{
+ unsigned long flags;
+ char *dma_addr;
+ unsigned int nslots, stride, index, wrap;
+ 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;
+
+ if (!nslots)
+ BUG();
+
+ /*
+ * 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 >= io_tlb_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 = io_tlb_start + (index << IO_TLB_SHIFT);
+
+ /*
+ * Update the indices to avoid searching in
+ * the next round.
+ */
+ io_tlb_index = ((index + nslots) < io_tlb_nslabs
+ ? (index + nslots) : 0);
+
+ goto found;
+ }
+ index += stride;
+ if (index >= io_tlb_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.
+ */
+ io_tlb_orig_addr[index] = buffer;
+ if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
+ memcpy(dma_addr, buffer, size);
+
+ return dma_addr;
+}
+
+/*
+ * 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 - io_tlb_start) >> IO_TLB_SHIFT;
+ char *buffer = io_tlb_orig_addr[index];
+
+ /*
+ * First, sync the memory before unmapping the entry
+ */
+ if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+ /*
+ * bounce... copy the data back into the original buffer * and
+ * delete the bounce buffer.
+ */
+ memcpy(buffer, dma_addr, size);
+
+ /*
+ * 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)
+{
+ int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
+ char *buffer = io_tlb_orig_addr[index];
+
+ /*
+ * bounce... copy the data back into/from the original buffer
+ * XXX How do you handle DMA_BIDIRECTIONAL here ?
+ */
+ if (dir == DMA_FROM_DEVICE)
+ memcpy(buffer, dma_addr, size);
+ else if (dir == DMA_TO_DEVICE)
+ memcpy(dma_addr, buffer, size);
+ else
+ BUG();
+}
+
+void *
+swiotlb_alloc_coherent(struct device *hwdev, size_t size,
+ dma_addr_t *dma_handle, int flags)
+{
+ unsigned long dev_addr;
+ void *ret;
+ int order = get_order(size);
+
+ /*
+ * XXX fix me: the DMA API should pass us an explicit DMA mask
+ * instead, or use ZONE_DMA32 (ia64 overloads ZONE_DMA to be a ~32
+ * bit range instead of a 16MB one).
+ */
+ flags |= GFP_DMA;
+
+ ret = (void *)__get_free_pages(flags, order);
+ if (ret && address_needs_mapping(hwdev, virt_to_phys(ret))) {
+ /*
+ * The allocated memory isn't reachable by the device.
+ * Fall back on swiotlb_map_single().
+ */
+ free_pages((unsigned long) ret, order);
+ ret = NULL;
+ }
+ if (!ret) {
+ /*
+ * We are either out of memory or the device can't DMA
+ * to GFP_DMA memory; fall back on
+ * swiotlb_map_single(), which will grab memory from
+ * the lowest available address range.
+ */
+ dma_addr_t handle;
+ handle = swiotlb_map_single(NULL, NULL, size, DMA_FROM_DEVICE);
+ if (dma_mapping_error(handle))
+ return NULL;
+
+ ret = phys_to_virt(handle);
+ }
+
+ memset(ret, 0, size);
+ dev_addr = virt_to_phys(ret);
+
+ /* Confirm address can be DMA'd by device */
+ if (address_needs_mapping(hwdev, dev_addr)) {
+ printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016lx\n",
+ (unsigned long long)*hwdev->dma_mask, dev_addr);
+ panic("swiotlb_alloc_coherent: allocated memory is out of "
+ "range for device");
+ }
+ *dma_handle = dev_addr;
+ return ret;
+}
+
+void
+swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
+ dma_addr_t dma_handle)
+{
+ if (!(vaddr >= (void *)io_tlb_start
+ && vaddr < (void *)io_tlb_end))
+ free_pages((unsigned long) vaddr, get_order(size));
+ else
+ /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
+ swiotlb_unmap_single (hwdev, dma_handle, size, DMA_TO_DEVICE);
+}
+
+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", 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)
+{
+ unsigned long dev_addr = virt_to_phys(ptr);
+ void *map;
+
+ if (dir == DMA_NONE)
+ BUG();
+ /*
+ * 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 (!address_needs_mapping(hwdev, dev_addr) && !swiotlb_force)
+ return dev_addr;
+
+ /*
+ * Oh well, have to allocate and map a bounce buffer.
+ */
+ map = map_single(hwdev, ptr, size, dir);
+ if (!map) {
+ swiotlb_full(hwdev, size, dir, 1);
+ map = io_tlb_overflow_buffer;
+ }
+
+ dev_addr = virt_to_phys(map);
+
+ /*
+ * Ensure that the address returned is DMA'ble
+ */
+ if (address_needs_mapping(hwdev, dev_addr))
+ panic("map_single: bounce buffer is not DMA'ble");
+
+ return dev_addr;
+}
+
+/*
+ * Since DMA is i-cache coherent, any (complete) pages that were written via
+ * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
+ * flush them when they get mapped into an executable vm-area.
+ */
+static void
+mark_clean(void *addr, size_t size)
+{
+ unsigned long pg_addr, end;
+
+ pg_addr = PAGE_ALIGN((unsigned long) addr);
+ end = (unsigned long) addr + size;
+ while (pg_addr + PAGE_SIZE <= end) {
+ struct page *page = virt_to_page(pg_addr);
+ set_bit(PG_arch_1, &page->flags);
+ pg_addr += PAGE_SIZE;
+ }
+}
+
+/*
+ * 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)
+{
+ char *dma_addr = phys_to_virt(dev_addr);
+
+ if (dir == DMA_NONE)
+ BUG();
+ if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
+ unmap_single(hwdev, dma_addr, size, dir);
+ else if (dir == DMA_FROM_DEVICE)
+ mark_clean(dma_addr, size);
+}
+
+/*
+ * 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)
+{
+ char *dma_addr = phys_to_virt(dev_addr);
+
+ if (dir == DMA_NONE)
+ BUG();
+ if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
+ sync_single(hwdev, dma_addr, size, dir);
+ else if (dir == DMA_FROM_DEVICE)
+ mark_clean(dma_addr, size);
+}
+
+void
+swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, int dir)
+{
+ char *dma_addr = phys_to_virt(dev_addr);
+
+ if (dir == DMA_NONE)
+ BUG();
+ if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
+ sync_single(hwdev, dma_addr, size, dir);
+ else if (dir == DMA_FROM_DEVICE)
+ mark_clean(dma_addr, size);
+}
+
+/*
+ * 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)
+{
+ void *addr;
+ unsigned long dev_addr;
+ int i;
+
+ if (dir == DMA_NONE)
+ BUG();
+
+ for (i = 0; i < nelems; i++, sg++) {
+ addr = SG_ENT_VIRT_ADDRESS(sg);
+ dev_addr = virt_to_phys(addr);
+ if (swiotlb_force || address_needs_mapping(hwdev, dev_addr)) {
+ sg->dma_address = (dma_addr_t) virt_to_phys(map_single(hwdev, addr, sg->length, dir));
+ if (!sg->dma_address) {
+ /* 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;
+ }
+ } 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;
+
+ if (dir == DMA_NONE)
+ BUG();
+
+ for (i = 0; i < nelems; i++, sg++)
+ if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
+ unmap_single(hwdev, (void *) phys_to_virt(sg->dma_address), sg->dma_length, dir);
+ else if (dir == DMA_FROM_DEVICE)
+ mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
+}
+
+/*
+ * 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;
+
+ if (dir == DMA_NONE)
+ BUG();
+
+ for (i = 0; i < nelems; i++, sg++)
+ if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
+ sync_single(hwdev, (void *) 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;
+
+ if (dir == DMA_NONE)
+ BUG();
+
+ for (i = 0; i < nelems; i++, sg++)
+ if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
+ sync_single(hwdev, (void *) sg->dma_address,
+ sg->dma_length, dir);
+}
+
+int
+swiotlb_dma_mapping_error(dma_addr_t dma_addr)
+{
+ return (dma_addr == virt_to_phys(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 (virt_to_phys (io_tlb_end) - 1) <= mask;
+}
+
+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_alloc_coherent);
+EXPORT_SYMBOL(swiotlb_free_coherent);
+EXPORT_SYMBOL(swiotlb_dma_supported);
