dmaengine: ensure all DMA engine drivers initialize their cookies
Ensure all DMA engine drivers initialize their cookies in the same way,
so that they all behave in a similar fashion. This means their first
issued cookie will be 2 rather than 1, and will increment to INT_MAX
before returning 1 and starting over.
In connection with this, Dan Williams said:
> Russell King wrote:
> > Secondly, some DMA engine drivers initialize the dma_chan cookie to 0,
> > others to 1. Is there a reason for this, or are these all buggy?
>
> I know that ioat and iop-adma expect 0 to mean "I have cleaned up this
> descriptor and it is idle", and would break if zero was an in-flight
> cookie value. The reserved usage of zero is an driver internal
> concern, but I have no problem formalizing it as a reserved value.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c
index 4370b10..1f3a703 100644
--- a/drivers/dma/iop-adma.c
+++ b/drivers/dma/iop-adma.c
@@ -1545,6 +1545,7 @@
INIT_LIST_HEAD(&iop_chan->chain);
INIT_LIST_HEAD(&iop_chan->all_slots);
iop_chan->common.device = dma_dev;
+ dma_cookie_init(&iop_chan->common);
list_add_tail(&iop_chan->common.device_node, &dma_dev->channels);
if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {