[PATCH] irqchip/sifive-plic: Fix broken irq_set_affinity() callback

[Anup Patel]

On Tue, Oct 20, 2020 at 1:45 PM Greentime Hu <greentime.hu at sifive.com> wrote:
>
> It will always enable the interrupt after calling plic_set_affinity()
> however it should set to it previous setting. Staying disabled or enabled.
>
> This patch can also fix this pwm hang issue in Unleashed board.
>
> [  919.015783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
> [  919.020922] rcu:     0-...0: (0 ticks this GP)
> idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=105807
> [  919.030295]  (detected by 1, t=225825 jiffies, g=1561, q=3496)
> [  919.036109] Task dump for CPU 0:
> [  919.039321] kworker/0:1     R  running task        0    30      2 0x00000008
> [  919.046359] Workqueue: events set_brightness_delayed
> [  919.051302] Call Trace:
> [  919.053738] [<ffffffe000930d92>] __schedule+0x194/0x4de
> [  982.035783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
> [  982.040923] rcu:     0-...0: (0 ticks this GP)
> idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=113325
> [  982.050294]  (detected by 1, t=241580 jiffies, g=1561, q=3509)
> [  982.056108] Task dump for CPU 0:
> [  982.059321] kworker/0:1     R  running task        0    30      2 0x00000008
> [  982.066359] Workqueue: events set_brightness_delayed
> [  982.071302] Call Trace:
> [  982.073739] [<ffffffe000930d92>] __schedule+0x194/0x4de
> [..]
>
> Fixes: bb0fed1c60cc ("irqchip/sifive-plic: Switch to fasteoi flow")
> Signed-off-by: Greentime Hu <greentime.hu at sifive.com>
> ---
>  drivers/irqchip/irq-sifive-plic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> index eaa3e9fe54e9..4048657ece0a 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -151,7 +151,7 @@ static int plic_set_affinity(struct irq_data *d,
>                 return -EINVAL;
>
>         plic_irq_toggle(&priv->lmask, d, 0);
> -       plic_irq_toggle(cpumask_of(cpu), d, 1);
> +       plic_irq_toggle(cpumask_of(cpu), d, !irqd_irq_masked(d));
>
>         irq_data_update_effective_affinity(d, cpumask_of(cpu));
>
> --
> 2.28.0
>

Looks good to me.

Reviewed-by: Anup Patel <anup at brainfault.org>

Regards,
Anup