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Message-ID: <Pine.LNX.4.64.1108291948310.5065@axis700.grange>
Date: Mon, 29 Aug 2011 19:50:13 +0200 (CEST)
From: Guennadi Liakhovetski <g.liakhovetski@....de>
To: Vinod Koul <vinod.koul@...ux.intel.com>
cc: Linux Media Mailing List <linux-media@...r.kernel.org>,
Sakari Ailus <sakari.ailus@...well.research.nokia.com>,
Pawel Osciak <pawel@...iak.com>, linux-kernel@...r.kernel.org,
Mauro Carvalho Chehab <mchehab@...radead.org>,
Hans Verkuil <hverkuil@...all.nl>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Sascha Hauer <kernel@...gutronix.de>,
Dan Williams <dan.j.williams@...el.com>,
linux-arm-kernel@...ts.infradead.org,
Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH 1/2] dmaengine: ipu-idmac: add support for the DMA_PAUSE
control
On Mon, 29 Aug 2011, Vinod Koul wrote:
> On Thu, 2011-08-25 at 18:45 +0200, Guennadi Liakhovetski wrote:
> > 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: Guennadi Liakhovetski <g.liakhovetski@....de>
> Acked-by Vinod Koul <vinod.koul@...ux.intel.com>
>
> Do you want this to go thru slave-dma or media tree?
With your above ack I can pull it together with the final form of patch
2/2, when it's ready, via media tree.
Thanks
Guennadi
>
> --
> ~Vinod
> > ---
> > drivers/dma/ipu/ipu_idmac.c | 65 +++++++++++++++++++++++++++---------------
> > 1 files changed, 42 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
> > index c1a125e..42cdf1c 100644
> > --- a/drivers/dma/ipu/ipu_idmac.c
> > +++ b/drivers/dma/ipu/ipu_idmac.c
> > @@ -1306,6 +1306,7 @@ 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);
> > @@ -1427,39 +1428,58 @@ 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);
> >
> > - ipu_disable_channel(idmac, ichan,
> > - ichan->status >= IPU_CHANNEL_ENABLED);
> > + /* Return all descriptors into "prepared" state */
> > + list_for_each_safe(list, tmp, &ichan->queue)
> > + list_del_init(list);
> >
> > - tasklet_disable(&to_ipu(idmac)->tasklet);
> > + ichan->sg[0] = NULL;
> > + ichan->sg[1] = NULL;
> >
> > - /* ichan->queue is modified in ISR, have to spinlock */
> > - spin_lock_irqsave(&ichan->lock, flags);
> > - list_splice_init(&ichan->queue, &ichan->free_list);
> > + spin_unlock_irqrestore(&ipu->lock, flags);
> >
> > - if (ichan->desc)
> > - for (i = 0; i < ichan->n_tx_desc; i++) {
> > - struct idmac_tx_desc *desc = ichan->desc + i;
> > - if (list_empty(&desc->list))
> > - /* Descriptor was prepared, but not submitted */
> > - list_add(&desc->list, &ichan->free_list);
> > + ichan->status = IPU_CHANNEL_INITIALIZED;
> > + break;
> > + case DMA_TERMINATE_ALL:
> > + ipu_disable_channel(idmac, ichan,
> > + ichan->status >= IPU_CHANNEL_ENABLED);
> >
> > - async_tx_clear_ack(&desc->txd);
> > - }
> > + tasklet_disable(&ipu->tasklet);
> >
> > - ichan->sg[0] = NULL;
> > - ichan->sg[1] = NULL;
> > - spin_unlock_irqrestore(&ichan->lock, flags);
> > + /* ichan->queue is modified in ISR, have to spinlock */
> > + spin_lock_irqsave(&ichan->lock, flags);
> > + list_splice_init(&ichan->queue, &ichan->free_list);
> >
> > - tasklet_enable(&to_ipu(idmac)->tasklet);
> > + if (ichan->desc)
> > + for (i = 0; i < ichan->n_tx_desc; i++) {
> > + struct idmac_tx_desc *desc = ichan->desc + i;
> > + if (list_empty(&desc->list))
> > + /* Descriptor was prepared, but not submitted */
> > + list_add(&desc->list, &ichan->free_list);
> >
> > - ichan->status = IPU_CHANNEL_INITIALIZED;
> > + async_tx_clear_ack(&desc->txd);
> > + }
> > +
> > + ichan->sg[0] = NULL;
> > + ichan->sg[1] = NULL;
> > + spin_unlock_irqrestore(&ichan->lock, flags);
> > +
> > + tasklet_enable(&ipu->tasklet);
> > +
> > + ichan->status = IPU_CHANNEL_INITIALIZED;
> > + break;
> > + default:
> > + return -ENOSYS;
> > + }
> >
> > return 0;
> > }
> > @@ -1662,7 +1682,6 @@ 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);
>
>
>
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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