GPIO IRQ on P1022

Sun, 31 Jul 2011 03:38:36 -0700 

Hi,

I'm running kernel 3.0 on a custom board based on Freescale P1022.
The interrupt line of on-board FPGA is connected to GPIO2_9. FPGA
IRQ is level, active low. The GPIOs are mapped like this:

GPIOs 160-191, /soc@ffe00000/gpio-controller@f200:

GPIOs 192-223, /soc@ffe00000/gpio-controller@f100:

GPIOs 224-255, /soc@ffe00000/gpio-controller@f000:

I've verified that pin mixing is done correctly, and the
FPGA IRQ line is indeed configured as GPIO.

I have the following code in my driver:

    #define FPGA_IRQ_GPIO 169

    err = gpio_request(FPGA_IRQ_GPIO, "FPGA IRQ");
    if (err) {
printk(KERN_ERR "Failed to request FPGA IRQ GPIO, err=%d\n", err); 
        goto out;
    }

    gpio_direction_input(FPGA_IRQ_GPIO);

    irq = gpio_to_irq(FPGA_IRQ_GPIO);
    if (irq < 0) {
        printk(KERN_ERR "Failed to map FPGA GPIO to IRQ\n");
        goto out;
    }

    err = request_irq(irq, gsat_interrupt,
              IRQF_TRIGGER_FALLING, DRVNAME, priv);
Interrupt handler reads FPGA interrupt status register to clear interrupt 
    and exits.
What happens when I load my driver is single execution of interrupt handler followed by system freeze. Even if I call disable_irq() in interrupt handler the 
    system still freezes.

    I've added some prints to mpc8xxx_gpio.c driver, here's what I get:

    mpc8xxx_gpio_to_irq: offset 9
    mpc8xxx_gpio_irq_map: virq 31
irq: irq 9 on host /soc@ffe00000/gpio-controller@f200 mapped to virtual irq 31 
    mpc8xxx_irq_set_type: virq 9 flow_type 2
    mpc8xxx_irq_unmask: irq 9
    mpc8xxx_gpio_irq_cascade: irq 47
    mpc8xxx_irq_mask: irq 9
    mpc8xxx_irq_ack: irq 9


What am I doing wrong ?

Thanks a lot.

Felix.



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