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Commit 1d3564d9 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Mauro Carvalho Chehab
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[media] dmaengine: ipu-idmac: add support for the DMA_PAUSE control 



To support multi-size buffers in the mx3_camera V4L2 driver we have to be
able to stop DMA on a channel without releasing descriptors and completely
halting the hardware. Use the DMA_PAUSE control to implement this mode.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: default avatarVinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 2d86401c

drivers/dma/ipu/ipu_idmac.c

+42 −23
Original line number Diff line number Diff line
@@ -1307,6 +1307,7 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id) 
	    ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0) {

		callback = descnew->txd.callback;

		callback_param = descnew->txd.callback_param;

		list_del_init(&descnew->list);

		spin_unlock(&ichan->lock);

		if (callback)

			callback(callback_param);
@@ -1428,17 +1429,32 @@ static int __idmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, 
{

	struct idmac_channel *ichan = to_idmac_chan(chan);

	struct idmac *idmac = to_idmac(chan->device);

	struct ipu *ipu = to_ipu(idmac);

	struct list_head *list, *tmp;

	unsigned long flags;

	int i;



	/* Only supports DMA_TERMINATE_ALL */

	if (cmd != DMA_TERMINATE_ALL)

		return -ENXIO;

	switch (cmd) {

	case DMA_PAUSE:

		spin_lock_irqsave(&ipu->lock, flags);

		ipu_ic_disable_task(ipu, chan->chan_id);



		/* Return all descriptors into "prepared" state */

		list_for_each_safe(list, tmp, &ichan->queue)

			list_del_init(list);



		ichan->sg[0] = NULL;

		ichan->sg[1] = NULL;



		spin_unlock_irqrestore(&ipu->lock, flags);



		ichan->status = IPU_CHANNEL_INITIALIZED;

		break;

	case DMA_TERMINATE_ALL:

		ipu_disable_channel(idmac, ichan,

				    ichan->status >= IPU_CHANNEL_ENABLED);



	tasklet_disable(&to_ipu(idmac)->tasklet);

		tasklet_disable(&ipu->tasklet);



		/* ichan->queue is modified in ISR, have to spinlock */

		spin_lock_irqsave(&ichan->lock, flags);
@@ -1458,9 +1474,13 @@ static int __idmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, 
		ichan->sg[1] = NULL;

		spin_unlock_irqrestore(&ichan->lock, flags);



	tasklet_enable(&to_ipu(idmac)->tasklet);

		tasklet_enable(&ipu->tasklet);



		ichan->status = IPU_CHANNEL_INITIALIZED;

		break;

	default:

		return -ENOSYS;

	}



	return 0;

}
@@ -1663,7 +1683,6 @@ static void __exit ipu_idmac_exit(struct ipu *ipu) 
		struct idmac_channel *ichan = ipu->channel + i;



		idmac_control(&ichan->dma_chan, DMA_TERMINATE_ALL, 0);

		idmac_prep_slave_sg(&ichan->dma_chan, NULL, 0, DMA_NONE, 0);

	}



	dma_async_device_unregister(&idmac->dma);