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i2c: tegra: Synchronize DMA before termination 

DMA transfer could be completed, but CPU (which handles DMA interrupt)
may get too busy and can't handle the interrupt in a timely manner,
despite of DMA IRQ being raised. In this case the DMA state needs to
synchronized before terminating DMA transfer in order not to miss the
DMA transfer completion.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Dmitry Osipenko 2020-03-24 22:12:17 +03:00 committed by Wolfram Sang
parent a900aeac25
commit 8814044fe0
1 changed files with 9 additions and 0 deletions
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9
drivers/i2c/busses/i2c-tegra.c
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@ -1219,6 +1219,15 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
time_left = tegra_i2c_wait_completion_timeout(
i2c_dev, &i2c_dev->dma_complete, xfer_time);
/*
* Synchronize DMA first, since dmaengine_terminate_sync()
* performs synchronization after the transfer's termination
* and we want to get a completion if transfer succeeded.
*/
dmaengine_synchronize(i2c_dev->msg_read ?
i2c_dev->rx_dma_chan :
i2c_dev->tx_dma_chan);
dmaengine_terminate_sync(i2c_dev->msg_read ?
i2c_dev->rx_dma_chan :
i2c_dev->tx_dma_chan);