[PATCH 3/4] media: rkisp1: Fix IRQ handling due to shared interrupts

[Adam Ford]

On Tue, Dec 5, 2023 at 2:27 AM Tomi Valkeinen
<tomi.valkeinen at ideasonboard.com> wrote:
>
> On 05/12/2023 10:20, Laurent Pinchart wrote:
> > Hi Tomi,
> >
> > Thank you for the patch.
> >
> > On Tue, Dec 05, 2023 at 10:09:34AM +0200, Tomi Valkeinen wrote:
> >> The driver requests the interrupts as IRQF_SHARED, so the interrupt
> >> handlers can be called at any time. If such a call happens while the ISP
> >> is powered down, the SoC will hang as the driver tries to access the
> >> ISP registers.
> >
> > Is IRQF_SHARED actually needed ?
>
> I don't have any answer to that, but it seems to have always been there.
> Dropping it would simplify the code, but we can only do that if we are
> sure all the platforms the ISP is used on or will be used on won't share
> the interrupt.

I can't speak for the Rockchip, but from what I can see, the imx8mp
has multiple causes for Interrupt 74 and  75, but they all appear to
be ISP1 and ISP2 related.

adam
>
>   Tomi
>
> >> Fix this by adding a new field, 'irqs_enabled', which is used to bail
> >> out from the interrupt handler when the ISP is not operational.
> >>
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
> >> ---
> >>   .../media/platform/rockchip/rkisp1/rkisp1-capture.c |  3 +++
> >>   .../media/platform/rockchip/rkisp1/rkisp1-common.h  |  2 ++
> >>   drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c |  3 +++
> >>   drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c | 21 +++++++++++++++++++++
> >>   drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c |  3 +++
> >>   5 files changed, 32 insertions(+)
> >>
> >> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c
> >> index b50b044d22af..e92067897f28 100644
> >> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c
> >> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c
> >> @@ -779,6 +779,9 @@ irqreturn_t rkisp1_capture_isr(int irq, void *ctx)
> >>      unsigned int i;
> >>      u32 status;
> >>
> >> +    if (!rkisp1->irqs_enabled)
> >> +            return IRQ_NONE;
> >> +
> >>      status = rkisp1_read(rkisp1, RKISP1_CIF_MI_MIS);
> >>      if (!status)
> >>              return IRQ_NONE;
> >> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> >> index ec28907d978e..7f97fdf6e24c 100644
> >> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> >> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> >> @@ -465,6 +465,7 @@ struct rkisp1_debug {
> >>    * @debug:    debug params to be exposed on debugfs
> >>    * @info:     version-specific ISP information
> >>    * @irqs:          IRQ line numbers
> >> + * @irqs_enabled:  the hardware is enabled and can cause interrupts
> >>    */
> >>   struct rkisp1_device {
> >>      void __iomem *base_addr;
> >> @@ -488,6 +489,7 @@ struct rkisp1_device {
> >>      struct rkisp1_debug debug;
> >>      const struct rkisp1_info *info;
> >>      int irqs[RKISP1_NUM_IRQS];
> >> +    bool irqs_enabled;
> >>   };
> >>
> >>   /*
> >> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
> >> index 47f4353a1784..f6b54654b435 100644
> >> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
> >> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
> >> @@ -184,6 +184,9 @@ irqreturn_t rkisp1_csi_isr(int irq, void *ctx)
> >>      struct rkisp1_device *rkisp1 = dev_get_drvdata(dev);
> >>      u32 val, status;
> >>
> >> +    if (!rkisp1->irqs_enabled)
> >> +            return IRQ_NONE;
> >> +
> >>      status = rkisp1_read(rkisp1, RKISP1_CIF_MIPI_MIS);
> >>      if (!status)
> >>              return IRQ_NONE;
> >> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> >> index 1d60f4b8bd09..fbe03f7864e3 100644
> >> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> >> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> >> @@ -306,6 +306,23 @@ static int __maybe_unused rkisp1_runtime_suspend(struct device *dev)
> >>   {
> >>      struct rkisp1_device *rkisp1 = dev_get_drvdata(dev);
> >>
> >> +    rkisp1->irqs_enabled = false;
> >> +    /* Make sure the IRQ handler will see the above */
> >> +    mb();
> >> +
> >> +    /*
> >> +     * Wait until any running IRQ handler has returned. The IRQ handler
> >> +     * may get called even after this (as it's a shared interrupt line)
> >> +     * but the 'irqs_enabled' flag will make the handler return immediately.
> >> +     */
> >> +    for (unsigned int i = 0; i < RKISP1_NUM_IRQS; ++i) {
> >> +            if (rkisp1->irqs[i] == -1)
> >> +                    continue;
> >> +
> >> +            if (i == 0 || rkisp1->irqs[i - 1] != rkisp1->irqs[i])
> >> +                    synchronize_irq(rkisp1->irqs[i]);
> >> +    }
> >> +
> >>      clk_bulk_disable_unprepare(rkisp1->clk_size, rkisp1->clks);
> >>      return pinctrl_pm_select_sleep_state(dev);
> >>   }
> >> @@ -322,6 +339,10 @@ static int __maybe_unused rkisp1_runtime_resume(struct device *dev)
> >>      if (ret)
> >>              return ret;
> >>
> >> +    rkisp1->irqs_enabled = true;
> >> +    /* Make sure the IRQ handler will see the above */
> >> +    mb();
> >> +
> >>      return 0;
> >>   }
> >>
> >> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> >> index dafbfd230542..d6b8786661ad 100644
> >> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> >> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> >> @@ -1082,6 +1082,9 @@ irqreturn_t rkisp1_isp_isr(int irq, void *ctx)
> >>      struct rkisp1_device *rkisp1 = dev_get_drvdata(dev);
> >>      u32 status, isp_err;
> >>
> >> +    if (!rkisp1->irqs_enabled)
> >> +            return IRQ_NONE;
> >> +
> >>      status = rkisp1_read(rkisp1, RKISP1_CIF_ISP_MIS);
> >>      if (!status)
> >>              return IRQ_NONE;
> >
>