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SubjectRe: [PATCH HACK] powerpc: quick hack to get a functional eHEA with hardirq preemption
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Sebastien Dugue <sebastien.dugue@bull.net> wrote on 15.09.2008 10:04:06:
> [PATCH HACK] powerpc: quick hack to get a functional eHEA with
> hardirq preemption
>
> Sebastien Dugue
>
> to:
>
> 15.09.2008 10:07
>
> Cc:
>
> linux-ppc, linux-kernel, Linux-rt, netdev, Jan-Bernd Themann, Thomas
> Q Klein, Christoph Raisch, jean-pierre.dion, gilles.carry, tinytim
>
>
> WARNING: HACK - HACK - HACK
> Not-Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
> ---
> --- a/arch/powerpc/kernel/ibmebus.c
> +++ b/arch/powerpc/kernel/ibmebus.c
> @@ -41,6 +41,7 @@
> - return request_irq(irq, handler, irq_flags, devname, dev_id);
> + ret = request_irq(irq, handler, irq_flags, devname, dev_id);
> +
> + desc = irq_desc + irq;
> + desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
> + desc->status |= IRQ_TYPE_EDGE_RISING;
> +
> + return ret;
This looks a bit like a set_irq_type call.
Don't know if this is fully implemented for xics though...
> }
> EXPORT_SYMBOL(ibmebus_request_irq);
>
> diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
> index b7b397a..6d366ca 100644
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -430,7 +430,7 @@ handle_fasteoi_irq(unsigned int irq, struct
> irq_desc *desc)
> action = desc->action;
> if (unlikely(!action || (desc->status & (IRQ_INPROGRESS |
> IRQ_DISABLED)))) {
> - desc->status |= IRQ_PENDING;
> + desc->status |= IRQ_PENDING | IRQ_MASKED;
> if (desc->chip->mask)
> desc->chip->mask(irq);
> goto out;
> @@ -439,9 +439,10 @@ handle_fasteoi_irq(unsigned int irq, struct
> irq_desc *desc)
> desc->status |= IRQ_INPROGRESS;
> /*
> * In the threaded case we fall back to a mask+eoi sequence:
> + * excepted for edge interrupts which are not masked.
> */
> if (redirect_hardirq(desc)) {
> - if (desc->chip->mask)
> + if (desc->chip->mask && !(desc->status & IRQ_TYPE_EDGE_BOTH))
> desc->chip->mask(irq);
> goto out;
> }
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 3bffa20..3e39c71 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -788,9 +788,12 @@ static void do_hardirq(struct irq_desc *desc)
> thread_simple_irq(desc);
> else if (desc->handle_irq == handle_level_irq)
> thread_level_irq(desc);
> - else if (desc->handle_irq == handle_fasteoi_irq)
> - thread_fasteoi_irq(desc);
> - else if (desc->handle_irq == handle_edge_irq)
> + else if (desc->handle_irq == handle_fasteoi_irq) {
> + if (desc->status & IRQ_TYPE_EDGE_BOTH)
> + thread_edge_irq(desc);
> + else
> + thread_fasteoi_irq(desc);
> + } else if (desc->handle_irq == handle_edge_irq)
> thread_edge_irq(desc);
> else
> thread_do_irq(desc);
> --
> 1.6.0.1.308.gede4c
>
According to the specs at some point in the system the HEA IRQs have a edge
characteristic.
But since PCI-E edge and level can both be forwarded through a message
interface
(HEA is not PCI-E, it's only connected to the same internal bus, where the
PHB resides)

Anybody from the xics experts want to comment on this?



Gruss / Regards
Christoph R. & Jan-Bernd



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