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Subject[PATCH 6 of 9] swiotlb: Store phys address in io_tlb_orig_addr array
Date
From
From: Becky Bruce <beckyb@kernel.crashing.org>

When we enable swiotlb for platforms that support HIGHMEM, we
can no longer store the virtual address of the original dma
buffer, because that buffer might not have a permament mapping.
Change the iotlb code to instead store the physical address of
the original buffer.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
---
lib/swiotlb.c | 47 ++++++++++++++++++++++++-----------------------
1 files changed, 24 insertions(+), 23 deletions(-)
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -90,7 +90,7 @@
* We need to save away the original address corresponding to a mapped entry
* for the sync operations.
*/
-static unsigned char **io_tlb_orig_addr;
+static phys_addr_t *io_tlb_orig_addr;

/*
* Protect the above data structures in the map and unmap calls
@@ -197,7 +197,7 @@
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 *));
+ io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(phys_addr_t));

/*
* Get the overflow emergency buffer
@@ -271,12 +271,14 @@
io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
io_tlb_index = 0;

- io_tlb_orig_addr = (unsigned char **)__get_free_pages(GFP_KERNEL,
- get_order(io_tlb_nslabs * sizeof(char *)));
+ 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 cleanup3;

- memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(char *));
+ memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t));

/*
* Get the overflow emergency buffer
@@ -291,8 +293,8 @@
return 0;

cleanup4:
- free_pages((unsigned long)io_tlb_orig_addr, get_order(io_tlb_nslabs *
- sizeof(char *)));
+ free_pages((unsigned long)io_tlb_orig_addr,
+ get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
io_tlb_orig_addr = NULL;
cleanup3:
free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
@@ -327,7 +329,7 @@
* Allocates bounce buffer and returns its kernel virtual address.
*/
static void *
-map_single(struct device *hwdev, char *buffer, size_t size, int dir)
+map_single(struct device *hwdev, phys_addr_t phys, size_t size, int dir)
{
unsigned long flags;
char *dma_addr;
@@ -422,9 +424,9 @@
* needed.
*/
for (i = 0; i < nslots; i++)
- io_tlb_orig_addr[index+i] = buffer + (i << IO_TLB_SHIFT);
+ io_tlb_orig_addr[index+i] = phys + (i << IO_TLB_SHIFT);
if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
- memcpy(dma_addr, buffer, size);
+ memcpy(dma_addr, phys_to_virt(phys), size);

return dma_addr;
}
@@ -438,17 +440,17 @@
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];
+ phys_addr_t phys = io_tlb_orig_addr[index];

/*
* First, sync the memory before unmapping the entry
*/
- if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+ if (phys && ((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);
+ memcpy(phys_to_virt(phys), dma_addr, size);

/*
* Return the buffer to the free list by setting the corresponding
@@ -481,20 +483,20 @@
int dir, int target)
{
int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
- char *buffer = io_tlb_orig_addr[index];
+ phys_addr_t phys = io_tlb_orig_addr[index];

- buffer += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));
+ phys += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));

switch (target) {
case SYNC_FOR_CPU:
if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
- memcpy(buffer, dma_addr, size);
+ memcpy(phys_to_virt(phys), dma_addr, size);
else
BUG_ON(dir != DMA_TO_DEVICE);
break;
case SYNC_FOR_DEVICE:
if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
- memcpy(dma_addr, buffer, size);
+ memcpy(dma_addr, phys_to_virt(phys), size);
else
BUG_ON(dir != DMA_FROM_DEVICE);
break;
@@ -533,7 +535,7 @@
* swiotlb_map_single(), which will grab memory from
* the lowest available address range.
*/
- ret = map_single(hwdev, NULL, size, DMA_FROM_DEVICE);
+ ret = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
if (!ret)
return NULL;
}
@@ -615,7 +617,7 @@
/*
* Oh well, have to allocate and map a bounce buffer.
*/
- map = map_single(hwdev, ptr, size, dir);
+ map = map_single(hwdev, virt_to_phys(ptr), size, dir);
if (!map) {
swiotlb_full(hwdev, size, dir, 1);
map = io_tlb_overflow_buffer;
@@ -760,18 +762,18 @@
int dir, struct dma_attrs *attrs)
{
struct scatterlist *sg;
- void *addr;
- dma_addr_t dev_addr;
int i;

BUG_ON(dir == DMA_NONE);

for_each_sg(sgl, sg, nelems, i) {
- addr = sg_virt(sg);
- dev_addr = swiotlb_virt_to_bus(hwdev, addr);
+ void *addr = sg_virt(sg);
+ dma_addr_t dev_addr = swiotlb_virt_to_bus(hwdev, addr);
+
if (range_needs_mapping(addr, sg->length) ||
address_needs_mapping(hwdev, dev_addr, sg->length)) {
- void *map = map_single(hwdev, addr, sg->length, dir);
+ void *map = map_single(hwdev, sg_phys(sg),
+ sg->length, dir);
if (!map) {
/* Don't panic here, we expect map_sg users
to do proper error handling. */



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