Re: [PATCH 1/1] irqchip: exynos-combiner: Save IRQ enable set on suspend

[Shuah Khan]

On Wed, Jun 10, 2015 at 7:10 AM, Javier Martinez Canillas
<javier.martinez@xxxxxxxxxxxxxxx> wrote:
> The Exynos interrupt combiner IP looses its state when the SoC enters
> into a low power state during a Suspend-to-RAM. This means that if a
> IRQ is used as a source, the interrupts for the devices are disabled
> when the system is resumed from a sleep state so are not triggered.
>
> Save the interrupt enable set register for each combiner group and
> restore it after resume to make sure that the interrupts are enabled.
>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
> ---
>
> Hello,
>
> I noticed this issue because after a S2R, IRQs for some devices didn't
> trigger anymore but others continued working and all of them had lines
> from a GPIO chip as their interrupt source.
>
> The only difference was that the GPIO pins that were not working after
> a resume, were the ones that had the interrupt combiner as interrupt
> parent.
>
> With this patch now all perhiperals are working correctly after a resume.
> Tested on an Exynos5250 Snow, Exynos5420 Peach Pit and Exynos5800 Peach Pi
> Chromebooks.
>
> Best regards,
> Javier
>
>  drivers/irqchip/exynos-combiner.c | 61 +++++++++++++++++++++++++++++++++++----
>  1 file changed, 56 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/irqchip/exynos-combiner.c b/drivers/irqchip/exynos-combiner.c
> index 5945223b73fa..69c710641bfa 100644
> --- a/drivers/irqchip/exynos-combiner.c
> +++ b/drivers/irqchip/exynos-combiner.c
> @@ -13,6 +13,7 @@
>  #include <linux/init.h>
>  #include <linux/io.h>
>  #include <linux/slab.h>
> +#include <linux/syscore_ops.h>
>  #include <linux/irqdomain.h>
>  #include <linux/irqchip/chained_irq.h>
>  #include <linux/interrupt.h>
> @@ -34,9 +35,14 @@ struct combiner_chip_data {
>         unsigned int irq_mask;
>         void __iomem *base;
>         unsigned int parent_irq;
> +#ifdef CONFIG_PM
> +       u32 pm_save;
> +#endif
>  };
>
> +static struct combiner_chip_data *combiner_data;
>  static struct irq_domain *combiner_irq_domain;
> +static unsigned int max_nr = 20;
>
>  static inline void __iomem *combiner_base(struct irq_data *data)
>  {
> @@ -170,12 +176,10 @@ static struct irq_domain_ops combiner_irq_domain_ops = {
>  };
>
>  static void __init combiner_init(void __iomem *combiner_base,
> -                                struct device_node *np,
> -                                unsigned int max_nr)
> +                                struct device_node *np)
>  {
>         int i, irq;
>         unsigned int nr_irq;
> -       struct combiner_chip_data *combiner_data;
>
>         nr_irq = max_nr * IRQ_IN_COMBINER;
>
> @@ -201,11 +205,56 @@ static void __init combiner_init(void __iomem *combiner_base,
>         }
>  }
>
> +#ifdef CONFIG_PM
> +
> +/**
> + * combiner_suspend - save interrupt combiner state before suspend
> + *
> + * Save the interrupt enable set register for all combiner groups since
> + * the state is lost when the system enters into a sleep state.
> + *
> + */
> +static int combiner_suspend(void)
> +{
> +       int i;
> +
> +       for (i = 0; i < max_nr; i++)
> +               combiner_data[i].pm_save =
> +                       __raw_readl(combiner_data[i].base + COMBINER_ENABLE_SET);
> +
> +       return 0;
> +}
> +
> +/**
> + * combiner_resume - restore interrupt combiner state after resume
> + *
> + * Restore the interrupt enable set register for all combiner groups since
> + * the state is lost when the system enters into a sleep state on suspend.
> + *
> + */
> +static void combiner_resume(void)
> +{
> +       int i;
> +
> +       for (i = 0; i < max_nr; i++)
> +               __raw_writel(combiner_data[i].pm_save,
> +                            combiner_data[i].base + COMBINER_ENABLE_SET);
> +}
> +
> +#else
> +#define combiner_suspend       NULL
> +#define combiner_resume                NULL
> +#endif
> +
> +static struct syscore_ops combiner_syscore_ops = {
> +       .suspend        = combiner_suspend,
> +       .resume         = combiner_resume,
> +};
> +

Should this be static const  struct syscore_ops?

>  static int __init combiner_of_init(struct device_node *np,
>                                    struct device_node *parent)
>  {
>         void __iomem *combiner_base;
> -       unsigned int max_nr = 20;
>
>         combiner_base = of_iomap(np, 0);
>         if (!combiner_base) {
> @@ -219,7 +268,9 @@ static int __init combiner_of_init(struct device_node *np,
>                         __func__, max_nr);
>         }
>
> -       combiner_init(combiner_base, np, max_nr);
> +       combiner_init(combiner_base, np);
> +
> +       register_syscore_ops(&combiner_syscore_ops);
>
>         return 0;
>  }
> --
> 2.1.4
>
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