Manuel,
Have you actually seen this happen (outside of inducing it manually)? I
have some concern that by doing this we may either miss interrupts on
devices that send a lot (by design) or miss a design bug in a system
because we are masking out some interrupts. I know that system
stability is important, but I don't like hiding problems.
=Kevin
On Tue, 2009-01-20 at 11:03 +0100, Manuel Lauss wrote:
> Introduce separate mack_ack callbacks which really do shut up the
> edge-triggered irqs when called. Without this change, high-frequency
> edge interrupts can result in an endless irq storm, hanging the system.
>
> This can be easily triggered for example by setting an irq to falling
> edge type and manually connecting the associated pin to ground.
>
> Signed-off-by: Manuel Lauss <mano@xxxxxxxxxxxxxxxxxxxxxxx>
> ---
> arch/mips/alchemy/common/irq.c | 32 ++++++++++++++++++++++++--------
> 1 files changed, 24 insertions(+), 8 deletions(-)
>
> diff --git a/arch/mips/alchemy/common/irq.c b/arch/mips/alchemy/common/irq.c
> index c88c821..60da581 100644
> --- a/arch/mips/alchemy/common/irq.c
> +++ b/arch/mips/alchemy/common/irq.c
> @@ -320,6 +320,16 @@ static void au1x_ic0_mask(unsigned int irq_nr)
> au_sync();
> }
>
> +static void au1x_ic0_maskack(unsigned int irq_nr)
> +{
> + unsigned int bit = irq_nr - AU1000_INTC0_INT_BASE;
> + au_writel(1 << bit, IC0_MASKCLR);
> + au_writel(1 << bit, IC0_WAKECLR);
> + au_writel(1 << bit, IC0_FALLINGCLR);
> + au_writel(1 << bit, IC0_RISINGCLR);
> + au_sync();
> +}
> +
> static void au1x_ic1_mask(unsigned int irq_nr)
> {
> unsigned int bit = irq_nr - AU1000_INTC1_INT_BASE;
> @@ -328,6 +338,16 @@ static void au1x_ic1_mask(unsigned int irq_nr)
> au_sync();
> }
>
> +static void au1x_ic1_maskack(unsigned int irq_nr)
> +{
> + unsigned int bit = irq_nr - AU1000_INTC1_INT_BASE;
> + au_writel(1 << bit, IC1_MASKCLR);
> + au_writel(1 << bit, IC1_WAKECLR);
> + au_writel(1 << bit, IC1_FALLINGCLR);
> + au_writel(1 << bit, IC1_RISINGCLR);
> + au_sync();
> +}
> +
> static void au1x_ic0_ack(unsigned int irq_nr)
> {
> unsigned int bit = irq_nr - AU1000_INTC0_INT_BASE;
> @@ -379,25 +399,21 @@ static int au1x_ic1_setwake(unsigned int irq, unsigned int on)
> /*
> * irq_chips for both ICs; this way the mask handlers can be
> * as short as possible.
> - *
> - * NOTE: the ->ack() callback is used by the handle_edge_irq
> - * flowhandler only, the ->mask_ack() one by handle_level_irq,
> - * so no need for an irq_chip for each type of irq (level/edge).
> */
> static struct irq_chip au1x_ic0_chip = {
> .name = "Alchemy-IC0",
> - .ack = au1x_ic0_ack, /* edge */
> + .ack = au1x_ic0_ack,
> .mask = au1x_ic0_mask,
> - .mask_ack = au1x_ic0_mask, /* level */
> + .mask_ack = au1x_ic0_maskack,
> .unmask = au1x_ic0_unmask,
> .set_type = au1x_ic_settype,
> };
>
> static struct irq_chip au1x_ic1_chip = {
> .name = "Alchemy-IC1",
> - .ack = au1x_ic1_ack, /* edge */
> + .ack = au1x_ic1_ack,
> .mask = au1x_ic1_mask,
> - .mask_ack = au1x_ic1_mask, /* level */
> + .mask_ack = au1x_ic1_maskack,
> .unmask = au1x_ic1_unmask,
> .set_type = au1x_ic_settype,
> .set_wake = au1x_ic1_setwake,
--
=Kevin
