[PATCH v4 03/33] dmaengine: apple-admac: use dmaengine BH callback

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

Replace the per-channel tasklet with the shared dmaengine BH helper.
The handler continues to run in softirq context while dmaengine owns
the common scheduling and teardown mechanism.

Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/dma/apple-admac.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/apple-admac.c b/drivers/dma/apple-admac.c
index 4531a301c018..2eb863d1bb58 100644
--- a/drivers/dma/apple-admac.c
+++ b/drivers/dma/apple-admac.c
@@ -97,7 +97,6 @@ struct admac_chan {
 	unsigned int no;
 	struct admac_data *host;
 	struct dma_chan chan;
-	struct tasklet_struct tasklet;
 
 	u32 carveout;
 
@@ -530,10 +529,7 @@ static int admac_terminate_all(struct dma_chan *chan)
 		list_add_tail(&adchan->current_tx->node, &adchan->to_free);
 		adchan->current_tx = NULL;
 	}
-	/*
-	 * Descriptors can only be freed after the tasklet
-	 * has been killed (in admac_synchronize).
-	 */
+	/* Descriptors are released once the BH is flushed in admac_synchronize */
 	list_splice_tail_init(&adchan->submitted, &adchan->to_free);
 	list_splice_tail_init(&adchan->issued, &adchan->to_free);
 	spin_unlock_irqrestore(&adchan->lock, flags);
@@ -552,7 +548,7 @@ static void admac_synchronize(struct dma_chan *chan)
 	list_splice_tail_init(&adchan->to_free, &head);
 	spin_unlock_irqrestore(&adchan->lock, flags);
 
-	tasklet_kill(&adchan->tasklet);
+	dmaengine_kill_bh(&adchan->chan);
 
 	list_for_each_entry_safe(adtx, _adtx, &head, node) {
 		list_del(&adtx->node);
@@ -671,7 +667,7 @@ static void admac_handle_status_desc_done(struct admac_data *ad, int channo)
 		tx->reclaimed_pos %= 2 * tx->buf_len;
 
 		admac_cyclic_write_desc(ad, channo, tx);
-		tasklet_schedule(&adchan->tasklet);
+		dmaengine_schedule_bh(&adchan->chan);
 	}
 	spin_unlock_irqrestore(&adchan->lock, flags);
 }
@@ -721,9 +717,9 @@ static irqreturn_t admac_interrupt(int irq, void *devid)
 	return IRQ_HANDLED;
 }
 
-static void admac_chan_tasklet(struct tasklet_struct *t)
+static void admac_chan_bh(struct dma_chan *chan)
 {
-	struct admac_chan *adchan = from_tasklet(adchan, t, tasklet);
+	struct admac_chan *adchan = to_admac_chan(chan);
 	struct admac_tx *adtx;
 	struct dmaengine_desc_callback cb;
 	struct dmaengine_result tx_result;
@@ -909,7 +905,7 @@ static int admac_probe(struct platform_device *pdev)
 		INIT_LIST_HEAD(&adchan->issued);
 		INIT_LIST_HEAD(&adchan->to_free);
 		list_add_tail(&adchan->chan.device_node, &dma->channels);
-		tasklet_setup(&adchan->tasklet, admac_chan_tasklet);
+		dmaengine_init_bh(&adchan->chan, admac_chan_bh);
 	}
 
 	err = reset_control_reset(ad->rstc);
-- 
2.43.0