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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Marek Vasut <marex@denx.de>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 19/97] spi: dw: Disable clock after unregistering the host
Date:   Fri, 23 Mar 2018 10:54:06 +0100
Message-Id: <20180323094158.546147392@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marek Vasut <marex@denx.de>


[ Upstream commit 400c18e3dc86e04ef5afec9b86a8586ca629b9e9 ]

The dw_mmio driver disables the block clock before unregistering
the host. The code unregistering the host may access the SPI block
registers. If register access happens with block clock disabled,
this may lead to a bus hang. Disable the clock after unregistering
the host to prevent such situation.

This bug was observed on Altera Cyclone V SoC.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/spi/spi-dw-mmio.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -120,8 +120,8 @@ static int dw_spi_mmio_remove(struct pla
 {
 	struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
 
-	clk_disable_unprepare(dwsmmio->clk);
 	dw_spi_remove_host(&dwsmmio->dws);
+	clk_disable_unprepare(dwsmmio->clk);
 
 	return 0;
 }