[media] dmaengine: ipu-idmac: add support for the DMA_PAUSE control
Guennadi Liakhovetski [Thu, 25 Aug 2011 16:26:53 +0000 (13:26 -0300)]
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@gmx.de>
Acked-by: Vinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/dma/ipu/ipu_idmac.c

index 6815905..ddc2a13 100644 (file)
@@ -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);
@@ -1428,39 +1429,58 @@ 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;
 }
@@ -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);