From: Rob Herring <robh@kernel.org> To: Mark Brown <broonie@kernel.org> Cc: Stefan Wahren <stefan.wahren@i2se.com>, Florian Fainelli <f.fainelli@gmail.com>, Scott Branden <sbranden@broadcom.com>, Marc Zyngier <marc.zyngier@arm.com>, Ray Jui <rjui@broadcom.com>, Alexander Graf <agraf@suse.de>, linux-spi@vger.kernel.org, Eric Anholt <eric@anholt.net>, bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] spi: bcm2835aux: ensure interrupts are enabled for shared handler Date: Thu, 3 May 2018 13:09:44 -0500 [thread overview] Message-ID: <20180503180945.3502-1-robh@kernel.org> (raw) 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> --- Compile tested only. I'll add something to the related github issue on this and hopefully someone can test and confirm. I'm assuming the 8250 driver can handle shared irqs correctly. Rob drivers/spi/spi-bcm2835aux.c | 5 +++++ 1 file changed, 5 insertions(+) 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) & -- 2.17.0
WARNING: multiple messages have this Message-ID (diff)
From: robh@kernel.org (Rob Herring) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] spi: bcm2835aux: ensure interrupts are enabled for shared handler Date: Thu, 3 May 2018 13:09:44 -0500 [thread overview] Message-ID: <20180503180945.3502-1-robh@kernel.org> (raw) 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 at broadcom.com Cc: linux-spi at vger.kernel.org Cc: linux-rpi-kernel at lists.infradead.org Cc: linux-arm-kernel at lists.infradead.org Signed-off-by: Rob Herring <robh@kernel.org> --- Compile tested only. I'll add something to the related github issue on this and hopefully someone can test and confirm. I'm assuming the 8250 driver can handle shared irqs correctly. Rob drivers/spi/spi-bcm2835aux.c | 5 +++++ 1 file changed, 5 insertions(+) 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) & -- 2.17.0
next reply other threads:[~2018-05-03 18:09 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-03 18:09 Rob Herring [this message] 2018-05-03 18:09 ` [PATCH] spi: bcm2835aux: ensure interrupts are enabled for shared handler Rob Herring 2018-05-03 18:31 ` Stefan Wahren 2018-05-03 18:31 ` Stefan Wahren 2018-05-03 21:15 ` Eric Anholt 2018-05-03 21:15 ` Eric Anholt 2018-05-03 22:06 ` Rob Herring 2018-05-03 22:06 ` Rob Herring 2018-05-03 22:36 ` Eric Anholt 2018-05-03 22:36 ` Eric Anholt 2018-05-03 23:06 ` Mark Brown 2018-05-03 23:06 ` Mark Brown 2018-05-03 23:19 ` Applied "spi: bcm2835aux: ensure interrupts are enabled for shared handler" to the spi tree Mark Brown 2018-05-03 23:19 ` Mark Brown
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20180503180945.3502-1-robh@kernel.org \ --to=robh@kernel.org \ --cc=agraf@suse.de \ --cc=bcm-kernel-feedback-list@broadcom.com \ --cc=broonie@kernel.org \ --cc=eric@anholt.net \ --cc=f.fainelli@gmail.com \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-rpi-kernel@lists.infradead.org \ --cc=linux-spi@vger.kernel.org \ --cc=marc.zyngier@arm.com \ --cc=rjui@broadcom.com \ --cc=sbranden@broadcom.com \ --cc=stefan.wahren@i2se.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.