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ARM: PL08x: fix atomic_t usage and tx_submit() return value range

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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>
This commit is contained in:
Russell King - ARM Linux
2011-01-03 22:31:04 +00:00
committed by Dan Williams
parent 4440aacf3a
commit 91aa5fadb8
2 changed files with 9 additions and 10 deletions
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include/linux/amba/pl08x.h
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@@ -174,7 +174,6 @@ struct pl08x_dma_chan {
struct pl08x_channel_data *cd;
dma_addr_t runtime_addr;
enum dma_data_direction runtime_direction;
atomic_t last_issued;
dma_cookie_t lc;
struct list_head desc_list;
struct pl08x_txd *at;