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authorRussell King - ARM Linux <linux@arm.linux.org.uk>2011-01-03 22:31:04 +0000
committerDan Williams <dan.j.williams@intel.com>2011-01-04 19:16:10 -0800
commit91aa5fadb831e7b6ea473a526a6b49c6dc4819ce (patch)
tree4f96e2649b8725b6f58bace588e90c9f38c3dc80 /drivers/dma/amba-pl08x.c
parent4440aacf3a171a0ab498feda58d100a320c5d9ff (diff)
ARM: PL08x: fix atomic_t usage and tx_submit() return value range
The last_issued variable uses an atomic type, which is only incremented inside a protected region, and then read. Everywhere else only reads the value, so it isn't using atomic_t correctly, and it doesn't even need to. Moreover, the DMA engine code provides us with a variable for this already - chan.cookie. Use chan.cookie instead. Also, avoid negative dma_cookie_t values - negative returns from tx_submit() mean failure, yet in reality we always succeed. Restart from cookie 1, just like other DMA engine drivers do. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dma/amba-pl08x.c')
-rw-r--r--drivers/dma/amba-pl08x.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 0809810f9e7..5d9a15652db 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -74,7 +74,6 @@
#include <asm/hardware/pl080.h>
#include <asm/dma.h>
#include <asm/mach/dma.h>
-#include <asm/atomic.h>
#include <asm/processor.h>
#include <asm/cacheflush.h>
@@ -1082,8 +1081,10 @@ static dma_cookie_t pl08x_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct pl08x_dma_chan *plchan = to_pl08x_chan(tx->chan);
- atomic_inc(&plchan->last_issued);
- tx->cookie = atomic_read(&plchan->last_issued);
+ plchan->chan.cookie += 1;
+ if (plchan->chan.cookie < 0)
+ plchan->chan.cookie = 1;
+ tx->cookie = plchan->chan.cookie;
/* This unlock follows the lock in the prep() function */
spin_unlock_irqrestore(&plchan->lock, plchan->lockflags);
@@ -1115,7 +1116,7 @@ pl08x_dma_tx_status(struct dma_chan *chan,
enum dma_status ret;
u32 bytesleft = 0;
- last_used = atomic_read(&plchan->last_issued);
+ last_used = plchan->chan.cookie;
last_complete = plchan->lc;
ret = dma_async_is_complete(cookie, last_complete, last_used);
@@ -1131,7 +1132,7 @@ pl08x_dma_tx_status(struct dma_chan *chan,
/*
* This cookie not complete yet
*/
- last_used = atomic_read(&plchan->last_issued);
+ last_used = plchan->chan.cookie;
last_complete = plchan->lc;
/* Get number of bytes left in the active transactions and queue */
@@ -1641,8 +1642,7 @@ static void pl08x_tasklet(unsigned long data)
/*
* Update last completed
*/
- plchan->lc =
- (plchan->at->tx.cookie);
+ plchan->lc = plchan->at->tx.cookie;
/*
* Callback to signal completion
@@ -1820,8 +1820,8 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
chan->name);
chan->chan.device = dmadev;
- atomic_set(&chan->last_issued, 0);
- chan->lc = atomic_read(&chan->last_issued);
+ chan->chan.cookie = 0;
+ chan->lc = 0;
spin_lock_init(&chan->lock);
INIT_LIST_HEAD(&chan->desc_list);