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

Laurent Pinchart
2023-12-05T08:20:24Z

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 ?

> 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@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;

--
Regards,

Laurent Pinchart