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Message-Id: <20180618081213.916723840@linuxfoundation.org>
Date: Mon, 18 Jun 2018 10:13:32 +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, Alexander Graf <agraf@...e.de>,
Marc Zyngier <marc.zyngier@....com>,
Mark Brown <broonie@...nel.org>, Eric Anholt <eric@...olt.net>,
Stefan Wahren <stefan.wahren@...e.com>,
Florian Fainelli <f.fainelli@...il.com>,
Ray Jui <rjui@...adcom.com>,
Scott Branden <sbranden@...adcom.com>,
bcm-kernel-feedback-list@...adcom.com, linux-spi@...r.kernel.org,
linux-rpi-kernel@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org,
Rob Herring <robh@...nel.org>,
Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.14 116/189] spi: bcm2835aux: ensure interrupts are enabled for shared handler
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rob Herring <robh@...nel.org>
[ Upstream commit bc519d9574618e47a0c788000fb78da95e18d953 ]
The BCM2835 AUX SPI has a shared interrupt line (with AUX UART).
Downstream fixes this with an AUX irqchip to demux the IRQ sources and a
DT change which breaks compatibility with older kernels. The AUX irqchip
was already rejected for upstream[1] and the DT change would break
working systems if the DTB is updated to a newer one. The latter issue
was brought to my attention by Alex Graf.
The root cause however is a bug in the shared handler. Shared handlers
must check that interrupts are actually enabled before servicing the
interrupt. Add a check that the TXEMPTY or IDLE interrupts are enabled.
[1] https://patchwork.kernel.org/patch/9781221/
Cc: Alexander Graf <agraf@...e.de>
Cc: Marc Zyngier <marc.zyngier@....com>
Cc: Mark Brown <broonie@...nel.org>
Cc: Eric Anholt <eric@...olt.net>
Cc: Stefan Wahren <stefan.wahren@...e.com>
Cc: Florian Fainelli <f.fainelli@...il.com>
Cc: Ray Jui <rjui@...adcom.com>
Cc: Scott Branden <sbranden@...adcom.com>
Cc: bcm-kernel-feedback-list@...adcom.com
Cc: linux-spi@...r.kernel.org
Cc: linux-rpi-kernel@...ts.infradead.org
Cc: linux-arm-kernel@...ts.infradead.org
Signed-off-by: Rob Herring <robh@...nel.org>
Reviewed-by: Eric Anholt <eric@...olt.net>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/spi/spi-bcm2835aux.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -184,6 +184,11 @@ static irqreturn_t bcm2835aux_spi_interr
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
irqreturn_t ret = IRQ_NONE;
+ /* IRQ may be shared, so return if our interrupts are disabled */
+ if (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_CNTL1) &
+ (BCM2835_AUX_SPI_CNTL1_TXEMPTY | BCM2835_AUX_SPI_CNTL1_IDLE)))
+ return ret;
+
/* check if we have data to read */
while (bs->rx_len &&
(!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
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