--- /dev/null
+/*
+ * 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@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.
+ * 05/09/10 linville Add support for syncing ranges, support syncing for
+ * DMA_BIDIRECTIONAL mappings, miscellaneous cleanup.
+ * 08/12/11 beckyb Add highmem support
+ */
+
+#include <linux/cache.h>
+#include <linux/dma-mapping.h>
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/swiotlb.h>
+#include <linux/pfn.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/highmem.h>
+#include <linux/gfp.h>
+
+#include <asm/io.h>
+#include <asm/dma.h>
+#include <asm/scatterlist.h>
+
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/iommu-helper.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/swiotlb.h>
+
+#define OFFSET(val,align) ((unsigned long) \
+ ( (val) & ( (align) - 1)))
+
+#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
+
+/*
+ * Minimum IO TLB size to bother booting with. Systems with mainly
+ * 64bit capable cards will only lightly use the swiotlb. If we can't
+ * allocate a contiguous 1MB, we're probably in trouble anyway.
+ */
+#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
+
+int swiotlb_force;
+
+/*
+ * Used to do a quick range check in swiotlb_tbl_unmap_single and
+ * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
+ * API.
+ */
+static phys_addr_t io_tlb_start, io_tlb_end;
+
+/*
+ * The number of IO TLB blocks (in groups of 64) between 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;
+
+static phys_addr_t 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.
+ */
+#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
+static phys_addr_t *io_tlb_orig_addr;
+
+/*
+ * Protect the above data structures in the map and unmap calls
+ */
+static DEFINE_SPINLOCK(io_tlb_lock);
+
+static int late_alloc;
+
+static int __init
+setup_io_tlb_npages(char *str)
+{
+ if (isdigit(*str)) {
+ io_tlb_nslabs = simple_strtoul(str, &str, 0);
+ /* 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 0;
+}
+early_param("swiotlb", setup_io_tlb_npages);
+/* make io_tlb_overflow tunable too? */
+
+unsigned long swiotlb_nr_tbl(void)
+{
+ return io_tlb_nslabs;
+}
+EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
+
+/* default to 64MB */
+#define IO_TLB_DEFAULT_SIZE (64UL<<20)
+unsigned long swiotlb_size_or_default(void)
+{
+ unsigned long size;
+
+ size = io_tlb_nslabs << IO_TLB_SHIFT;
+
+ return size ? size : (IO_TLB_DEFAULT_SIZE);
+}
+
+/* Note that this doesn't work with highmem page */
+static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
+ volatile void *address)
+{
+ return phys_to_dma(hwdev, virt_to_phys(address));
+}
+
+static bool no_iotlb_memory;
+
+void swiotlb_print_info(void)
+{
+ unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+ unsigned char *vstart, *vend;
+
+ if (no_iotlb_memory) {
+ pr_warn("software IO TLB: No low mem\n");
+ return;
+ }
+
+ vstart = phys_to_virt(io_tlb_start);
+ vend = phys_to_virt(io_tlb_end);
+
+ printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n",
+ (unsigned long long)io_tlb_start,
+ (unsigned long long)io_tlb_end,
+ bytes >> 20, vstart, vend - 1);
+}
+
+int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
+{
+ void *v_overflow_buffer;
+ unsigned long i, bytes;
+
+ bytes = nslabs << IO_TLB_SHIFT;
+
+ io_tlb_nslabs = nslabs;
+ io_tlb_start = __pa(tlb);
+ io_tlb_end = io_tlb_start + bytes;
+
+ /*
+ * Get the overflow emergency buffer
+ */
+ v_overflow_buffer = memblock_virt_alloc_low_nopanic(
+ PAGE_ALIGN(io_tlb_overflow),
+ PAGE_SIZE);
+ if (!v_overflow_buffer)
+ return -ENOMEM;
+
+ io_tlb_overflow_buffer = __pa(v_overflow_buffer);
+
+ /*
+ * 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 = memblock_virt_alloc(
+ PAGE_ALIGN(io_tlb_nslabs * sizeof(int)),
+ PAGE_SIZE);
+ io_tlb_orig_addr = memblock_virt_alloc(
+ PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)),
+ PAGE_SIZE);
+ for (i = 0; i < io_tlb_nslabs; i++) {
+ io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+ }
+ io_tlb_index = 0;
+
+ if (verbose)
+ swiotlb_print_info();
+
+ return 0;
+}
+
+/*
+ * Statically reserve bounce buffer space and initialize bounce buffer data
+ * structures for the software IO TLB used to implement the DMA API.
+ */
+void __init
+swiotlb_init(int verbose)
+{
+ size_t default_size = IO_TLB_DEFAULT_SIZE;
+ unsigned char *vstart;
+ unsigned long bytes;
+
+ if (!io_tlb_nslabs) {
+ io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
+ io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ }
+
+ bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+
+ /* Get IO TLB memory from the low pages */
+ vstart = memblock_virt_alloc_low_nopanic(PAGE_ALIGN(bytes), PAGE_SIZE);
+ if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
+ return;
+
+ if (io_tlb_start)
+ memblock_free_early(io_tlb_start,
+ PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
+ pr_warn("Cannot allocate SWIOTLB buffer");
+ no_iotlb_memory = true;
+}
+
+/*
+ * Systems with larger DMA zones (those that don't support ISA) can
+ * initialize the swiotlb later using the slab allocator if needed.
+ * This should be just like above, but with some error catching.
+ */
+int
+swiotlb_late_init_with_default_size(size_t default_size)
+{
+ unsigned long bytes, req_nslabs = io_tlb_nslabs;
+ unsigned char *vstart = NULL;
+ unsigned int order;
+ int rc = 0;
+
+ if (!io_tlb_nslabs) {
+ io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
+ io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ }
+
+ /*
+ * Get IO TLB memory from the low pages
+ */
+ order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
+ io_tlb_nslabs = SLABS_PER_PAGE << order;
+ bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+
+ while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
+ vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
+ order);
+ if (vstart)
+ break;
+ order--;
+ }
+
+ if (!vstart) {
+ io_tlb_nslabs = req_nslabs;
+ return -ENOMEM;
+ }
+ if (order != get_order(bytes)) {
+ printk(KERN_WARNING "Warning: only able to allocate %ld MB "
+ "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
+ io_tlb_nslabs = SLABS_PER_PAGE << order;
+ }
+ rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
+ if (rc)
+ free_pages((unsigned long)vstart, order);
+ return rc;
+}
+
+int
+swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
+{
+ unsigned long i, bytes;
+ unsigned char *v_overflow_buffer;
+
+ bytes = nslabs << IO_TLB_SHIFT;
+
+ io_tlb_nslabs = nslabs;
+ io_tlb_start = virt_to_phys(tlb);
+ io_tlb_end = io_tlb_start + bytes;
+
+ memset(tlb, 0, bytes);
+
+ /*
+ * Get the overflow emergency buffer
+ */
+ v_overflow_buffer = (void *)__get_free_pages(GFP_DMA,
+ get_order(io_tlb_overflow));
+ if (!v_overflow_buffer)
+ goto cleanup2;
+
+ io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer);
+
+ /*
+ * 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 = (unsigned int *)__get_free_pages(GFP_KERNEL,
+ get_order(io_tlb_nslabs * sizeof(int)));
+ if (!io_tlb_list)
+ goto cleanup3;
+
+ io_tlb_orig_addr = (phys_addr_t *)
+ __get_free_pages(GFP_KERNEL,
+ get_order(io_tlb_nslabs *
+ sizeof(phys_addr_t)));
+ if (!io_tlb_orig_addr)
+ goto cleanup4;
+
+ for (i = 0; i < io_tlb_nslabs; i++) {
+ io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+ }
+ io_tlb_index = 0;
+
+ swiotlb_print_info();
+
+ late_alloc = 1;
+
+ return 0;
+
+cleanup4:
+ free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
+ sizeof(int)));
+ io_tlb_list = NULL;
+cleanup3:
+ free_pages((unsigned long)v_overflow_buffer,
+ get_order(io_tlb_overflow));
+ io_tlb_overflow_buffer = 0;
+cleanup2:
+ io_tlb_end = 0;
+ io_tlb_start = 0;
+ io_tlb_nslabs = 0;
+ return -ENOMEM;
+}
+
+void __init swiotlb_free(void)
+{
+ if (!io_tlb_orig_addr)
+ return;
+
+ if (late_alloc) {
+ free_pages((unsigned long)phys_to_virt(io_tlb_overflow_buffer),
+ get_order(io_tlb_overflow));
+ free_pages((unsigned long)io_tlb_orig_addr,
+ get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
+ free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
+ sizeof(int)));
+ free_pages((unsigned long)phys_to_virt(io_tlb_start),
+ get_order(io_tlb_nslabs << IO_TLB_SHIFT));
+ } else {
+ memblock_free_late(io_tlb_overflow_buffer,
+ PAGE_ALIGN(io_tlb_overflow));
+ memblock_free_late(__pa(io_tlb_orig_addr),
+ PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
+ memblock_free_late(__pa(io_tlb_list),
+ PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
+ memblock_free_late(io_tlb_start,
+ PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
+ }
+ io_tlb_nslabs = 0;
+}
+
+int is_swiotlb_buffer(phys_addr_t paddr)
+{
+ return paddr >= io_tlb_start && paddr < io_tlb_end;
+}
+
+/*
+ * Bounce: copy the swiotlb buffer back to the original dma location
+ */
+static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
+ size_t size, enum dma_data_direction dir)
+{
+ unsigned long pfn = PFN_DOWN(orig_addr);
+ unsigned char *vaddr = phys_to_virt(tlb_addr);
+
+ if (PageHighMem(pfn_to_page(pfn))) {
+ /* The buffer does not have a mapping. Map it in and copy */
+ unsigned int offset = orig_addr & ~PAGE_MASK;
+ char *buffer;
+ unsigned int sz = 0;
+ unsigned long flags;
+
+ while (size) {
+ sz = min_t(size_t, PAGE_SIZE - offset, size);
+
+ local_irq_save(flags);
+ buffer = kmap_atomic(pfn_to_page(pfn));
+ if (dir == DMA_TO_DEVICE)
+ memcpy(vaddr, buffer + offset, sz);
+ else
+ memcpy(buffer + offset, vaddr, sz);
+ kunmap_atomic(buffer);
+ local_irq_restore(flags);
+
+ size -= sz;
+ pfn++;
+ vaddr += sz;
+ offset = 0;
+ }
+ } else if (dir == DMA_TO_DEVICE) {
+ memcpy(vaddr, phys_to_virt(orig_addr), size);
+ } else {
+ memcpy(phys_to_virt(orig_addr), vaddr, size);
+ }
+}
+
+phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
+ dma_addr_t tbl_dma_addr,
+ phys_addr_t orig_addr, size_t size,
+ enum dma_data_direction dir)
+{
+ unsigned long flags;
+ phys_addr_t tlb_addr;
+ unsigned int nslots, stride, index, wrap;
+ int i;
+ unsigned long mask;
+ unsigned long offset_slots;
+ unsigned long max_slots;
+
+ if (no_iotlb_memory)
+ panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
+
+ mask = dma_get_seg_boundary(hwdev);
+
+ tbl_dma_addr &= mask;
+
+ offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+
+ /*
+ * Carefully handle integer overflow which can occur when mask == ~0UL.
+ */
+ max_slots = mask + 1
+ ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
+ : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
+
+ /*
+ * 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);
+ index = ALIGN(io_tlb_index, stride);
+ if (index >= io_tlb_nslabs)
+ index = 0;
+ wrap = index;
+
+ do {
+ while (iommu_is_span_boundary(index, nslots, offset_slots,
+ max_slots)) {
+ index += stride;
+ if (index >= io_tlb_nslabs)
+ index = 0;
+ if (index == wrap)
+ goto not_found;
+ }
+
+ /*
+ * 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;
+ tlb_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);
+
+not_found:
+ spin_unlock_irqrestore(&io_tlb_lock, flags);
+ if (printk_ratelimit())
+ dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
+ return SWIOTLB_MAP_ERROR;
+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.
+ */
+ for (i = 0; i < nslots; i++)
+ io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
+ if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
+ swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
+
+ return tlb_addr;
+}
+EXPORT_SYMBOL_GPL(swiotlb_tbl_map_single);
+
+/*
+ * Allocates bounce buffer and returns its kernel virtual address.
+ */
+
+static phys_addr_t
+map_single(struct device *hwdev, phys_addr_t phys, size_t size,
+ enum dma_data_direction dir)
+{
+ dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start);
+
+ return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir);
+}
+
+/*
+ * dma_addr is the kernel virtual address of the bounce buffer to unmap.
+ */
+void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
+ size_t size, enum dma_data_direction dir)
+{
+ unsigned long flags;
+ int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
+ phys_addr_t orig_addr = io_tlb_orig_addr[index];
+
+ /*
+ * First, sync the memory before unmapping the entry
+ */
+ if (orig_addr != INVALID_PHYS_ADDR &&
+ ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+ swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
+
+ /*
+ * Return the buffer to the free list by setting the corresponding
+ * entries to indicate the number of contiguous 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;
+ io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+ }
+ /*
+ * 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);
+}
+EXPORT_SYMBOL_GPL(swiotlb_tbl_unmap_single);
+
+void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
+ size_t size, enum dma_data_direction dir,
+ enum dma_sync_target target)
+{
+ int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
+ phys_addr_t orig_addr = io_tlb_orig_addr[index];
+
+ if (orig_addr == INVALID_PHYS_ADDR)
+ return;
+ orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1);
+
+ switch (target) {
+ case SYNC_FOR_CPU:
+ if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
+ swiotlb_bounce(orig_addr, tlb_addr,
+ size, DMA_FROM_DEVICE);
+ else
+ BUG_ON(dir != DMA_TO_DEVICE);
+ break;
+ case SYNC_FOR_DEVICE:
+ if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
+ swiotlb_bounce(orig_addr, tlb_addr,
+ size, DMA_TO_DEVICE);
+ else
+ BUG_ON(dir != DMA_FROM_DEVICE);
+ break;
+ default:
+ BUG();
+ }
+}
+EXPORT_SYMBOL_GPL(swiotlb_tbl_sync_single);
+
+void *
+swiotlb_alloc_coherent(struct device *hwdev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flags)
+{
+ dma_addr_t dev_addr;
+ void *ret;
+ int order = get_order(size);
+ u64 dma_mask = DMA_BIT_MASK(32);
+
+ if (hwdev && hwdev->coherent_dma_mask)
+ dma_mask = hwdev->coherent_dma_mask;
+
+ ret = (void *)__get_free_pages(flags, order);
+ if (ret) {
+ dev_addr = swiotlb_virt_to_bus(hwdev, ret);
+ if (dev_addr + size - 1 > dma_mask) {
+ /*
+ * The allocated memory isn't reachable by the device.
+ */
+ 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 map_single(), which
+ * will grab memory from the lowest available address range.
+ */
+ phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
+ if (paddr == SWIOTLB_MAP_ERROR)
+ return NULL;
+
+ ret = phys_to_virt(paddr);
+ dev_addr = phys_to_dma(hwdev, paddr);
+
+ /* Confirm address can be DMA'd by device */
+ if (dev_addr + size - 1 > dma_mask) {
+ printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
+ (unsigned long long)dma_mask,
+ (unsigned long long)dev_addr);
+
+ /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
+ swiotlb_tbl_unmap_single(hwdev, paddr,
+ size, DMA_TO_DEVICE);
+ return NULL;
+ }
+ }
+
+ *dma_handle = dev_addr;
+ memset(ret, 0, size);
+
+ return ret;
+}
+EXPORT_SYMBOL(swiotlb_alloc_coherent);
+
+void
+swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
+ dma_addr_t dev_addr)
+{
+ phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
+
+ WARN_ON(irqs_disabled());
+ if (!is_swiotlb_buffer(paddr))
+ free_pages((unsigned long)vaddr, get_order(size));
+ else
+ /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE);
+}
+EXPORT_SYMBOL(swiotlb_free_coherent);
+
+static void
+swiotlb_full(struct device *dev, size_t size, enum dma_data_direction 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 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 "DMA: Out of SW-IOMMU space for %zu bytes at "
+ "device %s\n", size, dev ? dev_name(dev) : "?");
+
+ if (size <= io_tlb_overflow || !do_panic)
+ return;
+
+ if (dir == DMA_BIDIRECTIONAL)
+ panic("DMA: Random memory could be DMA accessed\n");
+ if (dir == DMA_FROM_DEVICE)
+ panic("DMA: Random memory could be DMA written\n");
+ if (dir == DMA_TO_DEVICE)
+ panic("DMA: Random memory could be DMA read\n");
+}
+
+/*
+ * Map a single buffer of the indicated size for DMA in streaming mode. The
+ * physical address to use is returned.
+ *
+ * Once the device is given the dma address, the device owns this memory until
+ * either swiotlb_unmap_page or swiotlb_dma_sync_single is performed.
+ */
+dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ phys_addr_t map, phys = page_to_phys(page) + offset;
+ dma_addr_t dev_addr = phys_to_dma(dev, phys);
+
+ BUG_ON(dir == DMA_NONE);
+ /*
+ * If the address happens to be in the device's DMA window,
+ * we can safely return the device addr and not worry about bounce
+ * buffering it.
+ */
+ if (dma_capable(dev, dev_addr, size) && !swiotlb_force)
+ return dev_addr;
+
+ trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
+
+ /* Oh well, have to allocate and map a bounce buffer. */
+ map = map_single(dev, phys, size, dir);
+ if (map == SWIOTLB_MAP_ERROR) {
+ swiotlb_full(dev, size, dir, 1);
+ return phys_to_dma(dev, io_tlb_overflow_buffer);
+ }
+
+ dev_addr = phys_to_dma(dev, map);
+
+ /* Ensure that the address returned is DMA'ble */
+ if (!dma_capable(dev, dev_addr, size)) {
+ swiotlb_tbl_unmap_single(dev, map, size, dir);
+ return phys_to_dma(dev, io_tlb_overflow_buffer);
+ }
+
+ return dev_addr;
+}
+EXPORT_SYMBOL_GPL(swiotlb_map_page);
+
+/*
+ * Unmap a single streaming mode DMA translation. The dma_addr and size must
+ * match what was provided for in a previous swiotlb_map_page 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 unmap_single(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir)
+{
+ phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
+
+ BUG_ON(dir == DMA_NONE);
+
+ if (is_swiotlb_buffer(paddr)) {
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
+ return;
+ }
+
+ if (dir != DMA_FROM_DEVICE)
+ return;
+
+ /*
+ * phys_to_virt doesn't work with hihgmem page but we could
+ * call dma_mark_clean() with hihgmem page here. However, we
+ * are fine since dma_mark_clean() is null on POWERPC. We can
+ * make dma_mark_clean() take a physical address if necessary.
+ */
+ dma_mark_clean(phys_to_virt(paddr), size);
+}
+
+void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ unmap_single(hwdev, dev_addr, size, dir);
+}
+EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
+
+/*
+ * Make physical memory consistent for a single streaming mode DMA translation
+ * after a transfer.
+ *
+ * If you perform a swiotlb_map_page() but wish to interrogate the buffer
+ * using the cpu, yet do not wish to teardown the dma mapping, you must
+ * call this function before doing so. At the next point you give the dma
+ * address back to the card, you must first perform a
+ * swiotlb_dma_sync_for_device, and then the device again owns the buffer
+ */
+static void
+swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir,
+ enum dma_sync_target target)
+{
+ phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
+
+ BUG_ON(dir == DMA_NONE);
+
+ if (is_swiotlb_buffer(paddr)) {
+ swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
+ return;
+ }
+
+ if (dir != DMA_FROM_DEVICE)
+ return;
+
+ dma_mark_clean(phys_to_virt(paddr), size);
+}
+
+void
+swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir)
+{
+ swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
+}
+EXPORT_SYMBOL(swiotlb_sync_single_for_cpu);
+
+void
+swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir)
+{
+ swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
+}
+EXPORT_SYMBOL(swiotlb_sync_single_for_device);
+
+/*
+ * Map a set of buffers described by scatterlist in streaming mode for DMA.
+ * This is the scatter-gather version of the above swiotlb_map_page
+ * 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_page are the
+ * same here.
+ */
+int
+swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+ struct scatterlist *sg;
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for_each_sg(sgl, sg, nelems, i) {
+ phys_addr_t paddr = sg_phys(sg);
+ dma_addr_t dev_addr = phys_to_dma(hwdev, paddr);
+
+ if (swiotlb_force ||
+ !dma_capable(hwdev, dev_addr, sg->length)) {
+ phys_addr_t map = map_single(hwdev, sg_phys(sg),
+ sg->length, dir);
+ if (map == SWIOTLB_MAP_ERROR) {
+ /* Don't panic here, we expect map_sg users
+ to do proper error handling. */
+ swiotlb_full(hwdev, sg->length, dir, 0);
+ swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
+ attrs);
+ sg_dma_len(sgl) = 0;
+ return 0;
+ }
+ sg->dma_address = phys_to_dma(hwdev, map);
+ } else
+ sg->dma_address = dev_addr;
+ sg_dma_len(sg) = sg->length;
+ }
+ return nelems;
+}
+EXPORT_SYMBOL(swiotlb_map_sg_attrs);
+
+int
+swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
+ enum dma_data_direction dir)
+{
+ return swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
+}
+EXPORT_SYMBOL(swiotlb_map_sg);
+
+/*
+ * Unmap a set of streaming mode DMA translations. Again, cpu read rules
+ * concerning calls here are the same as for swiotlb_unmap_page() above.
+ */
+void
+swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
+ int nelems, enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+ struct scatterlist *sg;
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for_each_sg(sgl, sg, nelems, i)
+ unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir);
+
+}
+EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
+
+void
+swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
+ enum dma_data_direction dir)
+{
+ return swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
+}
+EXPORT_SYMBOL(swiotlb_unmap_sg);
+
+/*
+ * 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.
+ */
+static void
+swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
+ int nelems, enum dma_data_direction dir,
+ enum dma_sync_target target)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sgl, sg, nelems, i)
+ swiotlb_sync_single(hwdev, sg->dma_address,
+ sg_dma_len(sg), dir, target);
+}
+
+void
+swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
+ int nelems, enum dma_data_direction dir)
+{
+ swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
+}
+EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
+
+void
+swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
+ int nelems, enum dma_data_direction dir)
+{
+ swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
+}
+EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
+
+int
+swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
+{
+ return (dma_addr == phys_to_dma(hwdev, io_tlb_overflow_buffer));
+}
+EXPORT_SYMBOL(swiotlb_dma_mapping_error);
+
+/*
+ * Return whether the given device DMA address mask can be supported
+ * properly. For example, if your device can only drive the low 24-bits
+ * during bus mastering, then you would pass 0x00ffffff as the mask to
+ * this function.
+ */
+int
+swiotlb_dma_supported(struct device *hwdev, u64 mask)
+{
+ return phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
+}
+EXPORT_SYMBOL(swiotlb_dma_supported);
Code Review / kvmfornfv.git / blobdiff