[PATCH] spi: dw: Disable clock after unregistering the host

[PATCH] spi: dw: Disable clock after unregistering the host

[Marek Vasut]

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-ynQEQJNshbs@public.gmane.org>
Cc: Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/spi/spi-dw-mmio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 447497e9124c..d25cc4037e23 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -115,8 +115,8 @@ static int dw_spi_mmio_remove(struct platform_device *pdev)
 {
 	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;
 }
-- 
2.11.0

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Applied "spi: dw: Disable clock after unregistering the host" to the spi tree

[Mark Brown]

The patch

   spi: dw: Disable clock after unregistering the host

has been applied to the spi tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 400c18e3dc86e04ef5afec9b86a8586ca629b9e9 Mon Sep 17 00:00:00 2001
From: Marek Vasut <marex-ynQEQJNshbs@public.gmane.org>
Date: Tue, 18 Apr 2017 20:09:06 +0200
Subject: [PATCH] spi: dw: Disable clock after unregistering the host

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-ynQEQJNshbs@public.gmane.org>
Cc: Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Signed-off-by: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/spi/spi-dw-mmio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 447497e9124c..d25cc4037e23 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -115,8 +115,8 @@ static int dw_spi_mmio_remove(struct platform_device *pdev)
 {
 	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;
 }
-- 
2.11.0

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