From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <515B5154.2000802@xenomai.org>
Date: Tue, 02 Apr 2013 23:44:52 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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	<5152BAA3.30508@xenomai.org> <5152BC4D.8050501@siemens.com>
	<5152EC25.7060004@xenomai.org> <5152F489.1000106@siemens.com>
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Subject: Re: [Xenomai] one-shot fasteoi irqs
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Xenomai <xenomai@xenomai.org>

On 03/27/2013 02:30 PM, Jan Kiszka wrote:

> I'm wondering now why we need this differently for the I-pipe case.
> 
> Let's revisit what happens with a fasteoi normally:
> 
> - it's masked only if it's a oneshot IRQ before calling the flow handler
> - it's unmasked after the flow handling if the thread was not woken up
> 
> With I-pipe we already enter handle_fasteoi_irq with the IRQ masked. The
> conditions and spots to unmask are:
> - from handle_fasteoi_irq if the thread wasn't woken up or we have
>   non-threaded or non-oneshot handling
> - otherwise on end_irq from the handler thread
> 
> Do you think this is correct? If so, I do not think it matches this
> patch yet.


Hi,

here is a much simpler patch:
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 11e75d1..a1c9918 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -421,6 +421,13 @@ static inline void preflow_handler(struct irq_desc *desc)
 static inline void preflow_handler(struct irq_desc *desc) { }
 #endif
 
+static void cond_release_fasteoi_irq(struct irq_desc *desc)
+{
+	if (desc->irq_data.chip->irq_release && 
+	    !irqd_irq_disabled(&desc->irq_data) && !desc->threads_oneshot)
+		desc->irq_data.chip->irq_release(&desc->irq_data);
+}
+
 /**
  *	handle_fasteoi_irq - irq handler for transparent controllers
  *	@irq:	the interrupt number
@@ -463,8 +470,7 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 
 #ifdef CONFIG_IPIPE
 	/* XXX: IRQCHIP_EOI_IF_HANDLED is ignored. */
-	if (desc->irq_data.chip->irq_release)
-		desc->irq_data.chip->irq_release(&desc->irq_data);
+	cond_release_fasteoi_irq(desc);
 out_eoi:
 #else  /* !CONFIG_IPIPE */
 	if (desc->istate & IRQS_ONESHOT)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e49a288..e7ae8bd 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -715,9 +715,14 @@ again:
 
 	desc->threads_oneshot &= ~action->thread_mask;
 
+#ifndef CONFIG_IPIPE
 	if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 	    irqd_irq_masked(&desc->irq_data))
 		unmask_irq(desc);
+#else /* CONFIG_IPIPE */
+	if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data))
+		desc->ipipe_end(desc->irq_data.irq, desc);
+#endif /* CONFIG_IPIPE */
 
 out_unlock:
 	raw_spin_unlock_irq(&desc->lock);


-- 
                                                                Gilles.