Re: [PATCH 1/2] irqdomain: support three-cell scheme interrupts

From: Alex Elder <elder@riscstar.com>
To: Yixun Lan <dlan@gentoo.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Inochi Amaoto <inochiama@gmail.com>,
	linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
	linux-riscv@lists.infradead.org, spacemit@lists.linux.dev
Subject: Re: [PATCH 1/2] irqdomain: support three-cell scheme interrupts
Date: Thu, 27 Feb 2025 10:12:51 -0600	[thread overview]
Message-ID: <8fce8a9c-7946-4e3c-bbf3-25f8b4f4466f@riscstar.com> (raw)
In-Reply-To: <20250227-04-gpio-irq-threecell-v1-1-4ae4d91baadc@gentoo.org>

On 2/27/25 5:24 AM, Yixun Lan wrote:
> The is a prerequisite patch to support parsing three-cell
> interrupts which encoded as <instance hwirq irqflag>,
> the translate function will always retrieve irq number and
> flag from last two cells.
> 
> Signed-off-by: Yixun Lan <dlan@gentoo.org>
> ---
>   kernel/irq/irqdomain.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index ec6d8e72d980f604ded2bfa2143420e0e0095920..cb874ab5e54a4763d601122becd63b6d759e55d2 100644
> --- a/kernel/irq/irqdomain.c
> +++ b/kernel/irq/irqdomain.c
> @@ -1208,10 +1208,17 @@ int irq_domain_translate_twocell(struct irq_domain *d,
>   				 unsigned long *out_hwirq,
>   				 unsigned int *out_type)
>   {

This function is meant for "twocell".  There is also another function
irq_domain_translate_onecell().  Why don't you just create
irq_domain_translate_threecell" instead?

					-Alex

> +	u32 irq, type;
> +
>   	if (WARN_ON(fwspec->param_count < 2))
>   		return -EINVAL;
> -	*out_hwirq = fwspec->param[0];
> -	*out_type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> +
> +	irq = fwspec->param_count - 2;
> +	type = fwspec->param_count - 1;
> +
> +	*out_hwirq = fwspec->param[irq];
> +	*out_type = fwspec->param[type] & IRQ_TYPE_SENSE_MASK;
> +
>   	return 0;
>   }
>   EXPORT_SYMBOL_GPL(irq_domain_translate_twocell);
> 

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