linux-kernel - [PATCH v4 7/8] i2c: tegra: Always terminate DMA transfer

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Message-Id: <20200112171430.27219-8-digetx@gmail.com>
Date:   Sun, 12 Jan 2020 20:14:29 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Mikko Perttunen <cyndis@...si.fi>,
        Wolfram Sang <wsa@...-dreams.de>
Cc:     linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 7/8] 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.

Tested-by: Thierry Reding <treding@...dia.com>
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 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