From 8ac695463f37af902e953d575d3f782e32e170da Mon Sep 17 00:00:00 2001 From: Russell King - ARM Linux Date: Tue, 6 Mar 2012 22:36:27 +0000 Subject: dmaengine: ensure all DMA engine drivers initialize their cookies MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Tested-by: Linus Walleij Reviewed-by: Linus Walleij Acked-by: Jassi Brar [imx-sdma.c & mxs-dma.c] Tested-by: Shawn Guo Signed-off-by: Vinod Koul --- drivers/dma/ioat/dma.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/dma/ioat') diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c index 97e100ce43e..31493d80e0e 100644 --- a/drivers/dma/ioat/dma.c +++ b/drivers/dma/ioat/dma.c @@ -109,6 +109,7 @@ void ioat_init_channel(struct ioatdma_device *device, struct ioat_chan_common *c chan->reg_base = device->reg_base + (0x80 * (idx + 1)); spin_lock_init(&chan->cleanup_lock); chan->common.device = dma; + dma_cookie_init(&chan->common); list_add_tail(&chan->common.device_node, &dma->channels); device->idx[idx] = chan; init_timer(&chan->timer); -- cgit v1.2.3-18-g5258