2020-01-06 01:06:34

by Dmitry Osipenko

Subject: [PATCH v3 8/9] i2c: tegra: Always terminate DMA transfer

It is possible that I2C could error out in the middle of DMA transfer and
in this case DMA channel needs to be reset, otherwise a follow up transfer
will fail because DMA channel stays blocked.

Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/i2c/busses/i2c-tegra.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 1a390e1bff72..3c7c86d4b0e4 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1220,11 +1220,12 @@ 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);

+ dmaengine_terminate_sync(i2c_dev->msg_read ?
+ i2c_dev->rx_dma_chan :
+ i2c_dev->tx_dma_chan);
+
if (time_left == 0) {
dev_err(i2c_dev->dev, "DMA transfer timeout\n");
- dmaengine_terminate_sync(i2c_dev->msg_read ?
- i2c_dev->rx_dma_chan :
- i2c_dev->tx_dma_chan);
tegra_i2c_init(i2c_dev, true);
return -ETIMEDOUT;
}
@@ -1237,11 +1238,6 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
memcpy(i2c_dev->msg_buf, i2c_dev->dma_buf,
msg->len);
}
-
- if (i2c_dev->msg_err != I2C_ERR_NONE)
- dmaengine_synchronize(i2c_dev->msg_read ?
- i2c_dev->rx_dma_chan :
- i2c_dev->tx_dma_chan);
}

time_left = tegra_i2c_wait_completion_timeout(
--
2.24.0

2020-01-07 12:40:42

by Thierry Reding

Subject: Re: [PATCH v3 8/9] i2c: tegra: Always terminate DMA transfer

On Mon, 06 Jan 2020 04:04:22 +0300, Dmitry Osipenko wrote:
> It is possible that I2C could error out in the middle of DMA transfer and
> in this case DMA channel needs to be reset, otherwise a follow up transfer
> will fail because DMA channel stays blocked.
>
> Signed-off-by: Dmitry Osipenko <[email protected]>
> ---
> drivers/i2c/busses/i2c-tegra.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)

Tested-by: Thierry Reding <[email protected]>