[PATCH v4 02/14] dmaengine: tegra-apb: Implement synchronization callback

[Dmitry Osipenko]

The ISR tasklet could be kept scheduled after DMA transfer termination,
let's add synchronization callback which blocks until tasklet is finished.

Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/dma/tegra20-apb-dma.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 319f31d27014..664e9c5df3ba 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -798,6 +798,13 @@ static int tegra_dma_terminate_all(struct dma_chan *dc)
 	return 0;
 }
 
+static void tegra_dma_synchronize(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+
+	tasklet_kill(&tdc->tasklet);
+}
+
 static unsigned int tegra_dma_sg_bytes_xferred(struct tegra_dma_channel *tdc,
 					       struct tegra_dma_sg_req *sg_req)
 {
@@ -1506,6 +1513,7 @@ static int tegra_dma_probe(struct platform_device *pdev)
 	tdma->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
 	tdma->dma_dev.device_config = tegra_dma_slave_config;
 	tdma->dma_dev.device_terminate_all = tegra_dma_terminate_all;
+	tdma->dma_dev.device_synchronize = tegra_dma_synchronize;
 	tdma->dma_dev.device_tx_status = tegra_dma_tx_status;
 	tdma->dma_dev.device_issue_pending = tegra_dma_issue_pending;
 
-- 
2.24.0