linux-kernel - Re: [PATCH v3 1/2] irq: add irq_domain support to generic-chip

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Message-ID: <4F27FB7D.9030003@gmail.com>
Date:	Tue, 31 Jan 2012 08:32:29 -0600
From:	Rob Herring <robherring2@...il.com>
To:	Shawn Guo <shawn.guo@...aro.org>
CC:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Grant Likely <grant.likely@...retlab.ca>, b-cousson@...com,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v3 1/2] irq: add irq_domain support to generic-chip

On 01/31/2012 08:13 AM, Shawn Guo wrote:
> On Mon, Jan 30, 2012 at 11:31:38AM -0600, Rob Herring wrote:
> ...
>> +#ifdef CONFIG_IRQ_DOMAIN
>> +static int irq_gc_irq_domain_match(struct irq_domain *d, struct device_node *np)
>> +{
>> +	struct irq_chip_generic *gc;
>> +
>> +	if (d->of_node != NULL && d->of_node == np) {
>> +		list_for_each_entry(gc, &gc_list, list) {
>> +			if ((gc == d->host_data) && (d == gc->domain))
>> +				return 1;
>> +		}
>> +	}
> 
> IIRC, we talked about this a little bit, but I'm still unsure how this
> works for imx5 tzic case, where we have the same one tzic device_node
> for 4 irqdomains representing 128 irq lines.  It seems to me the match
> function here will always find the first irqdomain of the 4 for any
> of those 128 tzic irqs.
> 
> The following is my code change against your branch for testing.  Am I
> missing anything?

The irq domain code is a bit different now, so it's matching differently
than before. See the match function. The host_data ptr for a domain is
set to the gc ptr. I then check that the gc->domain matches the domain
passed in. So the fact that 4 domains point to 1 device_node doesn't matter.

> 
> 8<---
> diff --git a/arch/arm/mach-imx/imx51-dt.c b/arch/arm/mach-imx/imx51-dt.c
> index e1b5edf..45abf11 100644
> --- a/arch/arm/mach-imx/imx51-dt.c
> +++ b/arch/arm/mach-imx/imx51-dt.c
> @@ -44,13 +44,6 @@ static const struct of_dev_auxdata
> imx51_auxdata_lookup[] __initconst = {
>         { /* sentinel */ }
>  };
> 
> -static int __init imx51_tzic_add_irq_domain(struct device_node *np,
> -                               struct device_node *interrupt_parent)
> -{
> -       irq_domain_add_legacy(np, 32, 0, 0, &irq_domain_simple_ops, NULL);
> -       return 0;
> -}
> -
>  static int __init imx51_gpio_add_irq_domain(struct device_node *np,
>                                 struct device_node *interrupt_parent)
>  {
> @@ -63,7 +56,6 @@ static int __init imx51_gpio_add_irq_domain(struct
> device_node *np,
>  }
> 
>  static const struct of_device_id imx51_irq_match[] __initconst = {
> -       { .compatible = "fsl,imx51-tzic", .data = imx51_tzic_add_irq_domain, },
>         { .compatible = "fsl,imx51-gpio", .data = imx51_gpio_add_irq_domain, },
>         { /* sentinel */ }
>  };
> 
> diff --git a/arch/arm/plat-mxc/tzic.c b/arch/arm/plat-mxc/tzic.c
> index 98308ec..ffb615d 100644
> --- a/arch/arm/plat-mxc/tzic.c
> +++ b/arch/arm/plat-mxc/tzic.c
> @@ -122,7 +122,9 @@ static __init void tzic_init_gc(unsigned int irq_start)
>         ct->regs.disable = TZIC_ENCLEAR0(idx);
>         ct->regs.enable = TZIC_ENSET0(idx);
> 
> -       irq_setup_generic_chip(gc, IRQ_MSK(32), 0, IRQ_NOREQUEST, 0);
> +       irq_setup_generic_chip_domain(gc,
> +               of_find_compatible_node(NULL, NULL, "fsl,tzic"),
> +               IRQ_MSK(32), 0, IRQ_NOREQUEST, 0);

Looks right, but I wouldn't lookup the node ptr every time.

>  }
> 
>  asmlinkage void __exception_irq_entry tzic_handle_irq(struct pt_regs *regs)
> --->8
> 
>> +	return 0;
>> +}
>> +
> ...
>> +void irq_setup_generic_chip_domain(struct irq_chip_generic *gc,
>> +			    struct device_node *node, u32 msk,
>> +			    enum irq_gc_flags flags, unsigned int clr,
>> +			    unsigned int set)
>> +{
>> +	struct irq_chip_type *ct = gc->chip_types;
>> +
>> +	if (!node) {
>> +		irq_setup_generic_chip(gc, msk, flags, clr, set);
>> +		return;
>> +	}
>> +
>> +	raw_spin_lock(&gc_lock);
>> +	list_add_tail(&gc->list, &gc_list);
>> +	raw_spin_unlock(&gc_lock);
>> +
>> +	/* Init mask cache ? */
>> +	if (flags & IRQ_GC_INIT_MASK_CACHE)
>> +		gc->mask_cache = irq_reg_readl(gc->reg_base + ct->regs.mask);
>> +
>> +	gc->flags = flags;
>> +	gc->irq_clr = clr;
>> +	gc->irq_set = set;
>> +
>> +	/* Users of domains should not use irq_base */
>> +	if ((int)gc->irq_base > 0)
>> +		gc->domain = irq_domain_add_legacy(node, fls(msk),
>> +						   gc->irq_base, 0,
>> +						   &irq_gc_irq_domain_ops, gc);
>> +	else {
>> +		gc->irq_base = 0;
>> +		gc->domain = irq_domain_add_linear(node, fls(msk),
>> +						   &irq_gc_irq_domain_ops, gc);
>> +	}
> 
> We have 4 generic_chips for tzic with irq_base as 0, 32, 64, 96.  In
> this case, we end up with having the first domain as the linear, and
> the other 3 as the legacy?

Umm, yes. So it should be '>= 0' instead until we stop using IRQ0. I
could base it on NULL node ptr instead...

For the DT case, you want irq_base to be -1.

Rob
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