Subject: Re: [PATCH v3 22/25] irq_domain/x86: Convert x86 (embedded) to use common irq_domain

From: Sebastian Andrzej Siewior <[email-masked]>
Date: Thu, 23 Feb 2012 22:22:15 +0100

On 02/23/2012 08:56 PM, Grant Likely wrote:
> On Wed, Feb 1, 2012 at 11:06 AM, Grant Likely<[email-masked]>  wrote:
>> On Wed, Feb 1, 2012 at 7:17 AM, Sebastian Andrzej Siewior
>> <[email-masked]>  wrote:
>>> * Grant Likely | 2012-01-30 12:58:42 [-0700]:
>>>
>>>> Ugh.  This isn't easy.  The legacy mapping really needs all the
>>>
>>> Feel free to merge this patch. I don't have the time to look at this now
>>> so I take a look at the ioapic later.
>>
>> There's no rush here.  I can leave it as-is with IRQ_DOMAIN turned off
>> for x86 for now.
>
> Turns out I have to enable IRQ_DOMAIN for x86 because the TI TWL4030
> driver needs it.  I do need to apply this patch.  Until something
> better can be implemented, can I change ioapic_add_ofnode() so that it
> allocates all irq_descs immediately.  It's not ideal, but every other
> approach I've looked at results in nasty hacks.
>
> Looking at the ioapic code, it appears to handle preallocated
> irq_descs gracefully.

Please merge your initial patch as-it.

> Does adding this loop help (apologies if it is whitespace damaged, I
> cut&paste it):
>
> diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
> index 3ae2ced..89c1310 100644
> --- a/arch/x86/kernel/devicetree.c
> +++ b/arch/x86/kernel/devicetree.c
> @@ -345,7 +345,7 @@ const struct irq_domain_ops ioapic_irq_domain_ops = {
>   static void __init ioapic_add_ofnode(struct device_node *np)
>   {
>   	struct resource r;
> -	int i, ret;
> +	int i, j, ret;
>
>   	ret = of_address_to_resource(np, 0,&r);
>   	if (ret) {
> @@ -361,6 +361,14 @@ static void __init ioapic_add_ofnode(struct
> device_node *np)
>
>   			gsi_cfg = mp_ioapic_gsi_routing(i);
>
> +			/*
> +			 * Preallocate irq_descs so that the legacy mapping
> +			 * works, but don't set them up.
> +			 * io_apic_setup_irq_pin_once() will finish the set up.
> +			 */
> +			for (j = 0; j<  32; j++)

It is not 32. If I remember correctly the first ioapic had 24 pins so
did the second. This is ioapic specifc.

> g.

Sebastian