[ARM] dma: fix dmabounce dma_sync_xxx() implementations
The dmabounce dma_sync_xxx() implementation have been broken for
quite some time; they all copy data between the DMA buffer and
the CPU visible buffer no irrespective of the change of ownership.
(IOW, a DMA_FROM_DEVICE mapping copies data from the DMA buffer
to the CPU buffer during a call to dma_sync_single_for_device().)
Fix it by getting rid of sync_single(), moving the contents into
the recently created dmabounce_sync_for_xxx() functions and adjusting
appropriately.
This also makes it possible to properly support the DMA range sync
functions.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 1cb880b..d4b0c60 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -205,6 +205,21 @@
/* ************************************************** */
+static struct safe_buffer *find_safe_buffer_dev(struct device *dev,
+ dma_addr_t dma_addr, const char *where)
+{
+ if (!dev || !dev->archdata.dmabounce)
+ return NULL;
+ if (dma_mapping_error(dev, dma_addr)) {
+ if (dev)
+ dev_err(dev, "Trying to %s invalid mapping\n", where);
+ else
+ pr_err("unknown device: Trying to %s invalid mapping\n", where);
+ return NULL;
+ }
+ return find_safe_buffer(dev->archdata.dmabounce, dma_addr);
+}
+
static inline dma_addr_t
map_single(struct device *dev, void *ptr, size_t size,
enum dma_data_direction dir)
@@ -274,19 +289,7 @@
unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
enum dma_data_direction dir)
{
- struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
- struct safe_buffer *buf = NULL;
-
- /*
- * Trying to unmap an invalid mapping
- */
- if (dma_mapping_error(dev, dma_addr)) {
- dev_err(dev, "Trying to unmap invalid mapping\n");
- return;
- }
-
- if (device_info)
- buf = find_safe_buffer(device_info, dma_addr);
+ struct safe_buffer *buf = find_safe_buffer_dev(dev, dma_addr, "unmap");
if (buf) {
BUG_ON(buf->size != size);
@@ -296,7 +299,7 @@
__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
buf->safe, buf->safe_dma_addr);
- DO_STATS ( device_info->bounce_count++ );
+ DO_STATS(dev->archdata.dmabounce->bounce_count++);
if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
void *ptr = buf->ptr;
@@ -317,74 +320,7 @@
dmac_clean_range(ptr, ptr + size);
outer_clean_range(__pa(ptr), __pa(ptr) + size);
}
- free_safe_buffer(device_info, buf);
- }
-}
-
-static int sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
- enum dma_data_direction dir)
-{
- struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
- struct safe_buffer *buf = NULL;
-
- if (device_info)
- buf = find_safe_buffer(device_info, dma_addr);
-
- if (buf) {
- /*
- * Both of these checks from original code need to be
- * commented out b/c some drivers rely on the following:
- *
- * 1) Drivers may map a large chunk of memory into DMA space
- * but only sync a small portion of it. Good example is
- * allocating a large buffer, mapping it, and then
- * breaking it up into small descriptors. No point
- * in syncing the whole buffer if you only have to
- * touch one descriptor.
- *
- * 2) Buffers that are mapped as DMA_BIDIRECTIONAL are
- * usually only synced in one dir at a time.
- *
- * See drivers/net/eepro100.c for examples of both cases.
- *
- * -ds
- *
- * BUG_ON(buf->size != size);
- * BUG_ON(buf->direction != dir);
- */
-
- dev_dbg(dev,
- "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
- __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
- buf->safe, buf->safe_dma_addr);
-
- DO_STATS ( device_info->bounce_count++ );
-
- switch (dir) {
- case DMA_FROM_DEVICE:
- dev_dbg(dev,
- "%s: copy back safe %p to unsafe %p size %d\n",
- __func__, buf->safe, buf->ptr, size);
- memcpy(buf->ptr, buf->safe, size);
- break;
- case DMA_TO_DEVICE:
- dev_dbg(dev,
- "%s: copy out unsafe %p to safe %p, size %d\n",
- __func__,buf->ptr, buf->safe, size);
- memcpy(buf->safe, buf->ptr, size);
- break;
- case DMA_BIDIRECTIONAL:
- BUG(); /* is this allowed? what does it mean? */
- default:
- BUG();
- }
- /*
- * No need to sync the safe buffer - it was allocated
- * via the coherent allocators.
- */
- return 0;
- } else {
- return 1;
+ free_safe_buffer(dev->archdata.dmabounce, buf);
}
}
@@ -447,18 +383,54 @@
int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
unsigned long off, size_t sz, enum dma_data_direction dir)
{
- dev_dbg(dev, "%s(dma=%#lx,off=%#lx,sz=%zx,dir=%x)\n",
+ struct safe_buffer *buf;
+
+ dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
__func__, addr, off, sz, dir);
- return sync_single(dev, addr, off + sz, dir);
+
+ buf = find_safe_buffer_dev(dev, addr, __func__);
+ if (!buf)
+ return 1;
+
+ dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
+ __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
+ buf->safe, buf->safe_dma_addr);
+
+ DO_STATS(dev->archdata.dmabounce->bounce_count++);
+
+ if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
+ dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
+ __func__, buf->safe + off, buf->ptr + off, sz);
+ memcpy(buf->ptr + off, buf->safe + off, sz);
+ }
+ return 0;
}
EXPORT_SYMBOL(dmabounce_sync_for_cpu);
int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
unsigned long off, size_t sz, enum dma_data_direction dir)
{
- dev_dbg(dev, "%s(dma=%#lx,off=%#lx,sz=%zx,dir=%x)\n",
+ struct safe_buffer *buf;
+
+ dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
__func__, addr, off, sz, dir);
- return sync_single(dev, addr, off + sz, dir);
+
+ buf = find_safe_buffer_dev(dev, addr, __func__);
+ if (!buf)
+ return 1;
+
+ dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
+ __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
+ buf->safe, buf->safe_dma_addr);
+
+ DO_STATS(dev->archdata.dmabounce->bounce_count++);
+
+ if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
+ dev_dbg(dev, "%s: copy out unsafe %p to safe %p, size %d\n",
+ __func__,buf->ptr + off, buf->safe + off, sz);
+ memcpy(buf->safe + off, buf->ptr + off, sz);
+ }
+ return 0;
}
EXPORT_SYMBOL(dmabounce_sync_for_device);