[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: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Vinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 42 insertions, 23 deletions

diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
index 6815905a772f..ddc2a1331822 100644
--- a/drivers/dma/ipu/ipu_idmac.c
+++ b/drivers/dma/ipu/ipu_idmac.c
@@ -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);