- 根目录:
- lib
- swiotlb.c
/*
* 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 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.
*/
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 = alloc_bootmem_low_pages_nopanic(
PAGE_ALIGN(io_tlb_overflow));
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 = alloc_bootmem_pages(PAGE_ALIGN(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_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
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 = alloc_bootmem_low_pages_nopanic(PAGE_ALIGN(bytes));
if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
return;
if (io_tlb_start)
free_bootmem(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;
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 = (phys_addr_t *)
__get_free_pages(GFP_KERNEL,
get_order(io_tlb_nslabs *
sizeof(phys_addr_t)));
if (!io_tlb_orig_addr)
goto cleanup4;
memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t));
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 {
free_bootmem_late(io_tlb_overflow_buffer,
PAGE_ALIGN(io_tlb_overflow));
free_bootmem_late(__pa(io_tlb_orig_addr),
PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
free_bootmem_late(__pa(io_tlb_list),
PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
free_bootmem_late(io_tlb_start,
PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
}
io_tlb_nslabs = 0;
}
static 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);
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.
*/
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 && ((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;
/*
* 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];
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;
/* 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);
sgl[0].dma_length = 0;
return 0;
}
sg->dma_address = phys_to_dma(hwdev, map);
} else
sg->dma_address = dev_addr;
sg->dma_length = 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_length, 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_length, 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);