[PATCH v4 29/33] dmaengine: pl330: route callbacks via channel BH

[Allen Pais <allen.lkml@gmail.com>]

Convert the per-channel tasklet to dmaengine_*_bh while keeping the
controller tasklet for non-callback events.

Initialize the channel BH once at probe time, alongside the other
per-channel state, rather than in pl330_alloc_chan_resources(). Unlike
tasklet_setup(), dmaengine_init_bh() must not be called again on an
already initialized channel, and a channel can be released and
re-requested many times. pl330_free_chan_resources() still drains the BH
when the channel is released.

Signed-off-by: Allen Pais <allen.lkml@gmail.com>
---
 drivers/dma/pl330.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 977a9fde80ad..6e88f5b45fb4 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -417,9 +417,6 @@ enum desc_status {
 };
 
 struct dma_pl330_chan {
-	/* Schedule desc completion */
-	struct tasklet_struct task;
-
 	/* DMA-Engine Channel */
 	struct dma_chan chan;
 
@@ -1575,7 +1572,7 @@ static void dma_pl330_rqcb(struct dma_pl330_desc *desc, enum pl330_op_err err)
 
 	spin_unlock_irqrestore(&pch->lock, flags);
 
-	tasklet_schedule(&pch->task);
+	dmaengine_schedule_bh(&pch->chan);
 }
 
 static void pl330_dotask(struct tasklet_struct *t)
@@ -2061,14 +2058,15 @@ static inline void fill_queue(struct dma_pl330_chan *pch)
 			desc->status = DONE;
 			dev_err(pch->dmac->ddma.dev, "%s:%d Bad Desc(%d)\n",
 					__func__, __LINE__, desc->txd.cookie);
-			tasklet_schedule(&pch->task);
+			dmaengine_schedule_bh(&pch->chan);
 		}
 	}
 }
 
-static void pl330_tasklet(struct tasklet_struct *t)
+static void pl330_tasklet(struct dma_chan *chan)
 {
-	struct dma_pl330_chan *pch = from_tasklet(pch, t, task);
+	struct dma_pl330_chan *pch = container_of(chan, struct dma_pl330_chan,
+						  chan);
 	struct dma_pl330_desc *desc, *_dt;
 	unsigned long flags;
 	bool power_down = false;
@@ -2174,8 +2172,6 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan)
 		return -ENOMEM;
 	}
 
-	tasklet_setup(&pch->task, pl330_tasklet);
-
 	spin_unlock_irqrestore(&pl330->lock, flags);
 
 	return 1;
@@ -2355,7 +2351,7 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
 	struct pl330_dmac *pl330 = pch->dmac;
 	unsigned long flags;
 
-	tasklet_kill(&pch->task);
+	dmaengine_kill_bh(&pch->chan);
 
 	pm_runtime_get_sync(pch->dmac->ddma.dev);
 	spin_lock_irqsave(&pl330->lock, flags);
@@ -2491,7 +2487,7 @@ static void pl330_issue_pending(struct dma_chan *chan)
 	list_splice_tail_init(&pch->submitted_list, &pch->work_list);
 	spin_unlock_irqrestore(&pch->lock, flags);
 
-	pl330_tasklet(&pch->task);
+	pl330_tasklet(&pch->chan);
 }
 
 /*
@@ -3121,6 +3117,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
 		pch->chan.device = pd;
 		pch->dmac = pl330;
 		pch->dir = DMA_NONE;
+		dmaengine_init_bh(&pch->chan, pl330_tasklet);
 
 		/* Add the channel to the DMAC list */
 		list_add_tail(&pch->chan.device_node, &pd->channels);
-- 
2.43.0