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authorRob Herring <robh@kernel.org>2018-05-03 13:09:44 -0500
committerMark Brown <broonie@kernel.org>2018-05-04 08:09:02 +0900
commitbc519d9574618e47a0c788000fb78da95e18d953 (patch)
treec1405de627823cde094254b4a65817d73c14a06a /drivers/spi/spi-bcm2835aux.c
parent602805fb618b018b7a41fbb3f93c1992b078b1ae (diff)
downloadlinux-bc519d9574618e47a0c788000fb78da95e18d953.tar.bz2
spi: bcm2835aux: ensure interrupts are enabled for shared handler
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@suse.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Brown <broonie@kernel.org> Cc: Eric Anholt <eric@anholt.net> Cc: Stefan Wahren <stefan.wahren@i2se.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ray Jui <rjui@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: linux-spi@vger.kernel.org Cc: linux-rpi-kernel@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Rob Herring <robh@kernel.org> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-bcm2835aux.c')
-rw-r--r--drivers/spi/spi-bcm2835aux.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 1431cb98fe40..3094d818cf06 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -184,6 +184,11 @@ static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)
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) &