On Tue 09 Oct 02:23 PDT 2018, Greg Kroah-Hartman wrote: > On Mon, Oct 08, 2018 at 11:33:38PM -0700, Nathan Chancellor wrote: > > On Mon, Oct 08, 2018 at 08:31:34PM +0200, Greg Kroah-Hartman wrote: > > > 4.4-stable review patch. If anyone has any objections, please let me know. > > > > > > ------------------ > > > > > > From: Stephen Boyd <swboyd@xxxxxxxxxxxx> > > > > > > [ Upstream commit b55326dc969ea2d704a008d9a97583b128f54f4f ] > > > > > > The interrupt controller hardware in this pin controller has two status > > > enable bits. The first "normal" status enable bit enables or disables > > > the summary interrupt line being raised when a gpio interrupt triggers > > > and the "raw" status enable bit allows or prevents the hardware from > > > latching an interrupt into the status register for a gpio interrupt. > > > Currently we just toggle the "normal" status enable bit in the mask and > > > unmask ops so that the summary irq interrupt going to the CPU's > > > interrupt controller doesn't trigger for the masked gpio interrupt. > > > > > > For a level triggered interrupt, the flow would be as follows: the pin > > > controller sees the interrupt, latches the status into the status > > > register, raises the summary irq to the CPU, summary irq handler runs > > > and calls handle_level_irq(), handle_level_irq() masks and acks the gpio > > > interrupt, the interrupt handler runs, and finally unmask the interrupt. > > > When the interrupt handler completes, we expect that the interrupt line > > > level will go back to the deasserted state so the genirq code can unmask > > > the interrupt without it triggering again. > > > > > > If we only mask the interrupt by clearing the "normal" status enable bit > > > then we'll ack the interrupt but it will continue to show up as pending > > > in the status register because the raw status bit is enabled, the > > > hardware hasn't deasserted the line, and thus the asserted state latches > > > into the status register again. When the hardware deasserts the > > > interrupt the pin controller still thinks there is a pending unserviced > > > level interrupt because it latched it earlier. This behavior causes > > > software to see an extra interrupt for level type interrupts each time > > > the interrupt is handled. > > > > > > Let's fix this by clearing the raw status enable bit for level type > > > interrupts so that the hardware stops latching the status of the > > > interrupt after we ack it. We don't do this for edge type interrupts > > > because it seems that toggling the raw status enable bit for edge type > > > interrupts causes spurious edge interrupts. > > > > > > Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx> > > > Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > > > Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> > > > Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > > > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> > > > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > > --- > > > drivers/pinctrl/qcom/pinctrl-msm.c | 24 ++++++++++++++++++++++++ > > > 1 file changed, 24 insertions(+) > > > > > > --- a/drivers/pinctrl/qcom/pinctrl-msm.c > > > +++ b/drivers/pinctrl/qcom/pinctrl-msm.c > > > @@ -577,6 +577,29 @@ static void msm_gpio_irq_mask(struct irq > > > spin_lock_irqsave(&pctrl->lock, flags); > > > > > > val = readl(pctrl->regs + g->intr_cfg_reg); > > > + /* > > > + * There are two bits that control interrupt forwarding to the CPU. The > > > + * RAW_STATUS_EN bit causes the level or edge sensed on the line to be > > > + * latched into the interrupt status register when the hardware detects > > > + * an irq that it's configured for (either edge for edge type or level > > > + * for level type irq). The 'non-raw' status enable bit causes the > > > + * hardware to assert the summary interrupt to the CPU if the latched > > > + * status bit is set. There's a bug though, the edge detection logic > > > + * seems to have a problem where toggling the RAW_STATUS_EN bit may > > > + * cause the status bit to latch spuriously when there isn't any edge > > > + * so we can't touch that bit for edge type irqs and we have to keep > > > + * the bit set anyway so that edges are latched while the line is masked. > > > + * > > > + * To make matters more complicated, leaving the RAW_STATUS_EN bit > > > + * enabled all the time causes level interrupts to re-latch into the > > > + * status register because the level is still present on the line after > > > + * we ack it. We clear the raw status enable bit during mask here and > > > + * set the bit on unmask so the interrupt can't latch into the hardware > > > + * while it's masked. > > > + */ > > > + if (irqd_get_trigger_type(d) & IRQ_TYPE_LEVEL_MASK) > > > + val &= ~BIT(g->intr_raw_status_bit); > > > + > > > val &= ~BIT(g->intr_enable_bit); > > > writel(val, pctrl->regs + g->intr_cfg_reg); > > > > > > @@ -598,6 +621,7 @@ static void msm_gpio_irq_unmask(struct i > > > spin_lock_irqsave(&pctrl->lock, flags); > > > > > > val = readl(pctrl->regs + g->intr_cfg_reg); > > > + val |= BIT(g->intr_raw_status_bit); > > > val |= BIT(g->intr_enable_bit); > > > writel(val, pctrl->regs + g->intr_cfg_reg); > > > > > > > > > > > > > Sigh, sorry, I caught this after I sent my initial all good email but > > this commit breaks NFC on my Pixel 2 XL (toggle becomes greyed out and > > apps that want to use it ask to enable it). I can't say why, I'm more > > than happy to debug but I'm assuming it's some voodoo that Qualcomm has > > done out of tree. I'll leave it up to you how to proceed given that I > > can't run mainline :( The patch corrects an issue that all level interrupts where delivered twice, so if that breaks NFC then there's something quite broken in that driver - or more likely something else broke. Can you please do some level of investigation to see where in the stack this broke, even if you can't run mainline. > > Ugh, I hate the qualcomm changes... > Noted... Regards, Bjorn > Given the mess that all of the msm driver changes have, I'll go drop > this patch from the stable tree as I don't want to deal with the > fall-out for when people merge this to their device-specific trees. > > thanks for testing and letting me know about this. >
