linux-kernel - [PATCH v4 1/4] spi: spi-fsl-dspi: Fix lockup if device is removed during SPI transfer

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Date:   Mon, 22 Jun 2020 13:05:40 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Mark Brown <broonie@...nel.org>, Peng Ma <peng.ma@....com>,
        linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Vladimir Oltean <vladimir.oltean@....com>,
        Wolfram Sang <wsa@...nel.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Krzysztof Kozlowski <krzk@...nel.org>, stable@...r.kernel.org
Subject: [PATCH v4 1/4] spi: spi-fsl-dspi: Fix lockup if device is removed during SPI transfer

During device removal, the driver should unregister the SPI controller
and stop the hardware.  Otherwise the dspi_transfer_one_message() could
wait on completion infinitely.

Additionally, calling spi_unregister_controller() first in device
removal reverse-matches the probe function, where SPI controller is
registered at the end.

Fixes: 05209f457069 ("spi: fsl-dspi: add missing clk_disable_unprepare() in dspi_remove()")
Cc: <stable@...r.kernel.org>
Reported-by: Vladimir Oltean <olteanv@...il.com>
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>

---

Changes since v3:
1. New patch.
---
 drivers/spi/spi-fsl-dspi.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 58190c94561f..ec0fd0d366eb 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -1434,9 +1434,18 @@ static int dspi_remove(struct platform_device *pdev)
 	struct fsl_dspi *dspi = spi_controller_get_devdata(ctlr);
 
 	/* Disconnect from the SPI framework */
+	spi_unregister_controller(dspi->ctlr);
+
+	/* Disable RX and TX */
+	regmap_update_bits(dspi->regmap, SPI_MCR,
+			   SPI_MCR_DIS_TXF | SPI_MCR_DIS_RXF,
+			   SPI_MCR_DIS_TXF | SPI_MCR_DIS_RXF);
+
+	/* Stop Running */
+	regmap_update_bits(dspi->regmap, SPI_MCR, SPI_MCR_HALT, SPI_MCR_HALT);
+
 	dspi_release_dma(dspi);
 	clk_disable_unprepare(dspi->clk);
-	spi_unregister_controller(dspi->ctlr);
 
 	return 0;
 }
-- 
2.17.1