Commit 8ac69546 authored by Russell King - ARM Linux's avatar Russell King - ARM Linux Committed by Vinod Koul
Browse files

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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarJassi Brar <jassisinghbrar@gmail.com>
[imx-sdma.c & mxs-dma.c]
Tested-by: default avatarShawn Guo <shawn.guo@linaro.org>
Signed-off-by: default avatarVinod Koul <vinod.koul@linux.intel.com>
parent 2a926e46

drivers/dma/fsldma.c

+1 −0
Original line number Diff line number Diff line
@@ -1292,6 +1292,7 @@ static int __devinit fsl_dma_chan_probe(struct fsldma_device *fdev, 
	chan->idle = true;



	chan->common.device = &fdev->common;

	dma_cookie_init(&chan->common);



	/* find the IRQ line, if it exists in the device tree */

	chan->irq = irq_of_parse_and_map(node, 0);

drivers/dma/imx-dma.c

+1 −0
Original line number Diff line number Diff line
@@ -347,6 +347,7 @@ static int __init imxdma_probe(struct platform_device *pdev) 
		spin_lock_init(&imxdmac->lock);



		imxdmac->chan.device = &imxdma->dma_device;

		dma_cookie_init(&imxdmac->chan);

		imxdmac->channel = i;



		/* Add the channel to the DMAC list */

drivers/dma/imx-sdma.c

+1 −0
Original line number Diff line number Diff line
@@ -1355,6 +1355,7 @@ static int __init sdma_probe(struct platform_device *pdev) 
		spin_lock_init(&sdmac->lock);



		sdmac->chan.device = &sdma->dma_device;

		dma_cookie_init(&sdmac->chan);

		sdmac->channel = i;



		/*

drivers/dma/ioat/dma.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

drivers/dma/iop-adma.c

+1 −0
Original line number Diff line number Diff line
@@ -1545,6 +1545,7 @@ static int __devinit iop_adma_probe(struct platform_device *pdev) 
	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)) {

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