Re: [PATCH v2] ARM: at91: aic can use fast eoi handler type

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Hi Will,

Le 06/01/2012 05:24 AM, Will Deacon a écrit :
Hi Ludovic,

Thanks for the update. Few comments inline.

On Thu, May 31, 2012 at 03:31:44PM +0100, ludovic.desroches@xxxxxxxxx wrote:
diff --git a/arch/arm/mach-at91/gpio.c b/arch/arm/mach-at91/gpio.c
index 325837a..a8bd715 100644
--- a/arch/arm/mach-at91/gpio.c
+++ b/arch/arm/mach-at91/gpio.c
@@ -593,7 +593,7 @@ static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
  	int		n;

  	/* temporarily mask (level sensitive) parent IRQ */
-	chip->irq_ack(idata);
+	chip->irq_mask(idata);

You don't need to mask the IRQ for fasteoi. However, you shouldn't be coding
the flow control like this -- use chained_irq_enter instead.

  	for (;;) {
  		/* Reading ISR acks pending (edge triggered) GPIO interrupts.
  		 * When there none are pending, we're finished unless we need
@@ -614,6 +614,7 @@ static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
  			n = find_next_bit(&isr, BITS_PER_LONG, n + 1);
+	chip->irq_eoi(idata);


Thanks I was not aware about this two functions.

diff --git a/arch/arm/mach-at91/irq.c b/arch/arm/mach-at91/irq.c
index 601b4ee..3aa18a6 100644
--- a/arch/arm/mach-at91/irq.c
+++ b/arch/arm/mach-at91/irq.c
@@ -55,6 +55,15 @@ static void at91_aic_unmask_irq(struct irq_data *d)
  	at91_aic_write(AT91_AIC_IECR, 1<<  d->hwirq);

+static void at91_aic_eoi(struct irq_data *d)
+	/*
+	 * Mark end-of-interrupt on AIC, the controller doesn't care about
+	 * the value written in this register.
+	 */
+	at91_aic_write(AT91_AIC_EOICR, 0);

Does the EOICR read as zero, or can you read back the value which you wrote?
In the latter case, writing the interrupt number can be a useful debugging
aid when you have to debug IRQ issues with JTAG. Your call.

It is a write only register so value read back is 0. Moreover there is a new version of AIC where writing '1 << d->hwirq' as no more sense since we have an interrupt select register.



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