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Commit 6ccc4c0d authored by Tony Lindgren's avatar Tony Lindgren
Browse files

ARM: OMAP3: Warn about spurious interrupts 



In the case of spurious interrupt, the handler for previous interrupt
handler needs to flush posted writes with a read back of the interrupt
ack register. Warn about handlers that need to flush posted writes.

Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent 64ce2907

arch/arm/mach-omap2/irq.c

+39 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#define INTC_REVISION		0x0000

#define INTC_SYSCONFIG		0x0010

#define INTC_SYSSTATUS		0x0014

#define INTC_SIR		0x0040

#define INTC_CONTROL		0x0048

#define INTC_MIR_CLEAR0		0x0088

#define INTC_MIR_SET0		0x008c
@@ -60,6 +61,30 @@ static u32 intc_bank_read_reg(struct omap_irq_bank *bank, u16 reg) 
	return __raw_readl(bank->base_reg + reg);

}



static int previous_irq;



/*

 * On 34xx we can get occasional spurious interrupts if the ack from

 * an interrupt handler does not get posted before we unmask. Warn about

 * the interrupt handlers that need to flush posted writes.

 */

static int omap_check_spurious(unsigned int irq)

{

	u32 sir, spurious;



	sir = intc_bank_read_reg(&irq_banks[0], INTC_SIR);

	spurious = sir >> 6;



	if (spurious > 1) {

		printk(KERN_WARNING "Spurious irq %i: 0x%08x, please flush "

					"posted write for irq %i\n",

					irq, sir, previous_irq);

		return spurious;

	}



	return 0;

}



/* XXX: FIQ and additional INTC support (only MPU at the moment) */

static void omap_ack_irq(unsigned int irq)

{
@@ -70,6 +95,20 @@ static void omap_mask_irq(unsigned int irq) 
{

	int offset = irq & (~(IRQ_BITS_PER_REG - 1));



	if (cpu_is_omap34xx()) {

		int spurious = 0;



		/*

		 * INT_34XX_GPT12_IRQ is also the spurious irq. Maybe because

		 * it is the highest irq number?

		 */

		if (irq == INT_34XX_GPT12_IRQ)

			spurious = omap_check_spurious(irq);



		if (!spurious)

			previous_irq = irq;

	}



	irq &= (IRQ_BITS_PER_REG - 1);



	intc_bank_write_reg(1 << irq, &irq_banks[0], INTC_MIR_SET0 + offset);