Re: External interrupt on 460EX

Hi, Stefan

Stefan Roese wrote:

Felix,

On Wednesday 15 October 2008, Felix Radensky wrote:
  

quoted

I'm running Linux 2.6.26 on custom board based on AMCC 460EX.
I'm trying to catch interrupt generated by CPLD, but without any luck.

The interrupt is connected to GPIO 45. U-Boot (1.3.4) configures this
pin as external interrupt 12 (interrupt 20 in UIC 3). I've added the
following
entry to board device tree (in opb section)

cpld@2,0 {
    device_type = "cpld";
    interrupts = <20 1>;
    

Is this interrupt active on rising edge? This is what you have configured 
here. When you need level, active low, then you need to write:

     interrupts = <20 8>;

And be careful which dts version you are using. Is this 20 decimal or hex?

  

The interrupt is indeed level, active low. Where can I find information 
on UIC
interrupt settings for device tree ? I'm using dtc 1.2.0, 20 is decimal. 
Is it ok ?

quoted

    interrupt-parent = <&UIC3>;
};

In my driver I do the following:

    /* Find CPLD node in device tree */
    np = of_find_node_by_type(NULL, "cpld");
    if (!np) {
        printk(KERN_INFO "No CPLD found in device tree\n");
        return -1;
    }

    /* Get and map irq number from device tree */
    cpld_irq = irq_of_parse_and_map(np, 0);
    if (cpld_irq == NO_IRQ) {
        printk(KERN_ERR "irq_of_parse_and_map failed\n");
        of_node_put(np);
        return -ENODEV;
    }

    /* Register CPLD interrupt handler */
    rc = request_irq(cpld_irq, cpld_interrupt,
             IRQF_TRIGGER_LOW, "CPLD", NULL);

And I see this interrupt in /proc/interrups after loading
the driver. However interrupt handler is never invoked,
although hardware guys see that GPIO line goes down
when interrupt is generated.

What am I doing wrong ?
    

Another idea is that you didn't configure the pin multiplexing correctly. Most 
external IRQ's are shared with other functions and/or GPIO's. You need to 
configure the multiplexing correctly for external IRQ functionality. This is 
usually done in U-Boot with the CFG_4xx_GPIO_TABLE. 

I suggest you check here first.
  

I've checked that, here's the relevant line from u-boot:
{GPIO1_BASE, GPIO_IN , GPIO_ALT3, GPIO_OUT_0}, /* GPIO45 CS(5)          
EOT/TC1         IRQ(12)*/

If I understand this code correctly, u-boot configures this line as ALT3 
(which is external IRQ 12)

Thanks.

Felix.