Hooking an IRQ on a modified mpc8349emitx board

Hooking an IRQ on a modified mpc8349emitx board

[Oscar Takeshita]

Hi,

I've been trying to hook an IRQ on a modified mpc8349emitx board without 
success.

The IRQ is hooked physically to IRQ1/GPIO2[13] on the mpc8349e. No other 
devices are
tied to this pin.

I'm using uboot 1.2.0 and kernel 2.6.22.19.

Do I need to have a dts entry for this interrupt in order to make
request_irq() succeed?

How can I find the IRQ number? I tried probe_irq_on/off unfortunately it 
did not work.
Would it be MPC83xx_IRQ_EXT1 in arch/powerpc/include/asm/mpc83xx.h ?

I'm new doing kernel work. Any hints appreciated.

Oscar

 

Re: Hooking an IRQ on a modified mpc8349emitx board

[Scott Wood]

On Wed, Sep 03, 2008 at 03:55:41PM -0700, Oscar Takeshita wrote:
> I've been trying to hook an IRQ on a modified mpc8349emitx board without 
> success.
> 
> The IRQ is hooked physically to IRQ1/GPIO2[13] on the mpc8349e. No other 
> devices are
> tied to this pin.
> 
> I'm using uboot 1.2.0 and kernel 2.6.22.19.
> 
> Do I need to have a dts entry for this interrupt in order to make
> request_irq() succeed?
> 
> How can I find the IRQ number? I tried probe_irq_on/off unfortunately it 
> did not work.
> Would it be MPC83xx_IRQ_EXT1 in arch/powerpc/include/asm/mpc83xx.h ?
> 
> I'm new doing kernel work. Any hints appreciated.

You need to describe the IRQ in a device tree node and use
irq_of_parse_and_map().  request_irq() takes virtual IRQ numbers.

Maybe we should put together an arch/powerpc FAQ...

-Scott

Re: Hooking an IRQ on a modified mpc8349emitx board

[Gary Thomas]

Scott Wood wrote:
> On Wed, Sep 03, 2008 at 03:55:41PM -0700, Oscar Takeshita wrote:
>> I've been trying to hook an IRQ on a modified mpc8349emitx board without 
>> success.
>>
>> The IRQ is hooked physically to IRQ1/GPIO2[13] on the mpc8349e. No other 
>> devices are
>> tied to this pin.
>>
>> I'm using uboot 1.2.0 and kernel 2.6.22.19.
>>
>> Do I need to have a dts entry for this interrupt in order to make
>> request_irq() succeed?
>>
>> How can I find the IRQ number? I tried probe_irq_on/off unfortunately it 
>> did not work.
>> Would it be MPC83xx_IRQ_EXT1 in arch/powerpc/include/asm/mpc83xx.h ?
>>
>> I'm new doing kernel work. Any hints appreciated.
> 
> You need to describe the IRQ in a device tree node and use
> irq_of_parse_and_map().  request_irq() takes virtual IRQ numbers.
> 
> Maybe we should put together an arch/powerpc FAQ...

That would be wonderful :-)  This could help many [of us] over these
initial speed-bumps.

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

Re: Hooking an IRQ on a modified mpc8349emitx board

[Oscar Takeshita]

Thanks Scott,

It is hooked and alive! Your couple of lines guided me through. Here's 
the outline of what I did after looking
at other powerpc drivers and the ePAPR document from Power.org:

1. Assumed that MPC83xx_IRQ_EXT1 (0x11 without offset) corresponds to IRQ1.
2. Created a node in my dts that looks like:

mydevice@40000 {
     device_type = "network";
     interrupts = <11 8>;
     interrupt-parent = < &ipic >;
}

3. On my kernel device driver I have the following outline:

struct device_node *np;
int irq;
if ((np = of_find_node_by_name(NULL, "mydevice")) == NULL) {
        printk(KERN_ERR "Can't find my device node\n");
        irq = -1;
}
else
        irq = irq_of_parse_and_map(np,0);


4. Ready to use request_irq() on irq!

Thanks,

Oscar

Scott Wood wrote:
> On Wed, Sep 03, 2008 at 03:55:41PM -0700, Oscar Takeshita wrote:
>   
>> I've been trying to hook an IRQ on a modified mpc8349emitx board without 
>> success.
>>
>> The IRQ is hooked physically to IRQ1/GPIO2[13] on the mpc8349e. No other 
>> devices are
>> tied to this pin.
>>
>> I'm using uboot 1.2.0 and kernel 2.6.22.19.
>>
>> Do I need to have a dts entry for this interrupt in order to make
>> request_irq() succeed?
>>
>> How can I find the IRQ number? I tried probe_irq_on/off unfortunately it 
>> did not work.
>> Would it be MPC83xx_IRQ_EXT1 in arch/powerpc/include/asm/mpc83xx.h ?
>>
>> I'm new doing kernel work. Any hints appreciated.
>>     
>
> You need to describe the IRQ in a device tree node and use
> irq_of_parse_and_map().  request_irq() takes virtual IRQ numbers.
>
> Maybe we should put together an arch/powerpc FAQ...
>
> -Scott
>
>
>