On Tue, 2014-01-07 at 13:38 +0800, Dongsheng Wang wrote:
> From: Wang Dongsheng <dongsheng.w...@freescale.com>
>
> Currently MPIC provides .mask, but not .disable. This means that
> effectively disable_irq() soft-disables the interrupt, and you get
> a .mask call if an interrupt actually occurs.
>
> I'm not sure if this was intended as a performance benefit (it seems common
> to omit .disable on powerpc interrupt controllers, but nowhere else), but it
> interacts badly with threaded/workqueue interrupts (including KVM
> reflection). In such cases, where the real interrupt handler does a
> disable_irq_nosync(), schedules defered handling, and returns, we get two
> interrupts for every real interrupt. The second interrupt does nothing
> but see that IRQ_DISABLED is set, and decide that it would be a good
> idea to actually call .mask.
We probably don't want to do that for edge, only level interrupts.
Cheers,
Ben.
>
> Signed-off-by: Scott Wood <scottw...@freescale.com>
> Signed-off-by: Wang Dongsheng <dongsheng.w...@freescale.com>
>
> diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
> index 0e166ed..dd7564b 100644
> --- a/arch/powerpc/sysdev/mpic.c
> +++ b/arch/powerpc/sysdev/mpic.c
> @@ -975,6 +975,7 @@ void mpic_set_destination(unsigned int virq, unsigned int
> cpuid)
> }
>
> static struct irq_chip mpic_irq_chip = {
> + .irq_disable = mpic_mask_irq,
> .irq_mask = mpic_mask_irq,
> .irq_unmask = mpic_unmask_irq,
> .irq_eoi = mpic_end_irq,
> @@ -984,6 +985,7 @@ static struct irq_chip mpic_irq_chip = {
>
> #ifdef CONFIG_SMP
> static struct irq_chip mpic_ipi_chip = {
> + .irq_disable = mpic_mask_ipi,
> .irq_mask = mpic_mask_ipi,
> .irq_unmask = mpic_unmask_ipi,
> .irq_eoi = mpic_end_ipi,
> @@ -991,6 +993,7 @@ static struct irq_chip mpic_ipi_chip = {
> #endif /* CONFIG_SMP */
>
> static struct irq_chip mpic_tm_chip = {
> + .irq_disable = mpic_mask_tm,
> .irq_mask = mpic_mask_tm,
> .irq_unmask = mpic_unmask_tm,
> .irq_eoi = mpic_end_irq,
> @@ -1001,6 +1004,7 @@ static struct irq_chip mpic_tm_chip = {
> static struct irq_chip mpic_irq_ht_chip = {
> .irq_startup = mpic_startup_ht_irq,
> .irq_shutdown = mpic_shutdown_ht_irq,
> + .irq_disable = mpic_mask_irq,
> .irq_mask = mpic_mask_irq,
> .irq_unmask = mpic_unmask_ht_irq,
> .irq_eoi = mpic_end_ht_irq,
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