linux-kernel - [PATCH 4.14 003/125] spi: spi-fsl-dspi: Fix lockup if device is removed during SPI transfer

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Date:   Mon, 20 Jul 2020 17:35:42 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vladimir Oltean <olteanv@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 003/125] spi: spi-fsl-dspi: Fix lockup if device is removed during SPI transfer

From: Krzysztof Kozlowski <krzk@...nel.org>

[ Upstream commit 7684580d45bd3d84ed9b453a4cadf7a9a5605a3f ]

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()")
Reported-by: Vladimir Oltean <olteanv@...il.com>
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
Cc: <stable@...r.kernel.org>
Link: https://lore.kernel.org/r/20200622110543.5035-1-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 d5b56b7814fe3..baf5274485004 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -1070,9 +1070,18 @@ static int dspi_remove(struct platform_device *pdev)
 	struct fsl_dspi *dspi = spi_master_get_devdata(master);
 
 	/* Disconnect from the SPI framework */
+	spi_unregister_controller(dspi->master);
+
+	/* 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_master(dspi->master);
 
 	return 0;
 }
-- 
2.25.1