linux-kernel - Re: [PATCH 1/4] irqchip: sifive: Support hierarchy irq domain

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Message-ID: <ad0a3b419a3f5c3475d5fafcc2a037fb@www.loen.fr>
Date:   Tue, 12 Nov 2019 13:52:09 +0109
From:   Marc Zyngier <maz@...nel.org>
To:     Yash Shah <yash.shah@...ive.com>
Cc:     <linus.walleij@...aro.org>, <bgolaszewski@...libre.com>,
        <robh+dt@...nel.org>, <mark.rutland@....com>, <palmer@...belt.com>,
        "Paul Walmsley ( Sifive)" <paul.walmsley@...ive.com>,
        <aou@...s.berkeley.edu>, <tglx@...utronix.de>,
        <jason@...edaemon.net>, <bmeng.cn@...il.com>,
        <atish.patra@....com>, Sagar Kadam <sagar.kadam@...ive.com>,
        <linux-gpio@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-riscv@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        Sachin Ghadi <sachin.ghadi@...ive.com>
Subject: Re: [PATCH 1/4] irqchip: sifive: Support hierarchy irq domain

On 2019-11-12 13:21, Yash Shah wrote:
> Add support for hierarchy irq domains. This is needed as 
> pre-requisite for
> gpio-sifive driver.
>
> Signed-off-by: Yash Shah <yash.shah@...ive.com>
> ---
>  drivers/irqchip/Kconfig           |  1 +
>  drivers/irqchip/irq-sifive-plic.c | 41
> +++++++++++++++++++++++++++++++++++----
>  2 files changed, 38 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index ccbb897..a398552 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -488,6 +488,7 @@ endmenu
>  config SIFIVE_PLIC
>  	bool "SiFive Platform-Level Interrupt Controller"
>  	depends on RISCV
> +	select IRQ_DOMAIN_HIERARCHY
>  	help
>  	   This enables support for the PLIC chip found in SiFive (and
>  	   potentially other) RISC-V systems.  The PLIC controls devices
> diff --git a/drivers/irqchip/irq-sifive-plic.c
> b/drivers/irqchip/irq-sifive-plic.c
> index 7d0a12f..2fa1c84 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -154,15 +154,48 @@ static struct irq_chip plic_chip = {
>  static int plic_irqdomain_map(struct irq_domain *d, unsigned int 
> irq,
>  			      irq_hw_number_t hwirq)
>  {
> -	irq_set_chip_and_handler(irq, &plic_chip, handle_fasteoi_irq);
> -	irq_set_chip_data(irq, NULL);
> +	irq_domain_set_info(d, irq, hwirq, &plic_chip, d->host_data,
> +			    handle_fasteoi_irq, NULL, NULL);
>  	irq_set_noprobe(irq);
>  	return 0;
>  }
>
> +static int plic_irq_domain_translate(struct irq_domain *d,
> +				     struct irq_fwspec *fwspec,
> +				     unsigned long *hwirq, unsigned int *type)
> +{
> +	if (WARN_ON(fwspec->param_count < 1))
> +		return -EINVAL;
> +	*hwirq = fwspec->param[0];
> +	*type = IRQ_TYPE_NONE;
> +	return 0;
> +}

This is actually what should be called irq_domain_translate_onecell().

Consider implementing that instead, and using it in this driver. I'm
pretty sure other drivers could use it (I spotted irq-nvic.c).

> +
> +static int plic_irq_domain_alloc(struct irq_domain *domain, unsigned
> int virq,
> +				 unsigned int nr_irqs, void *arg)
> +{
> +	int i, ret;
> +	irq_hw_number_t hwirq;
> +	unsigned int type = IRQ_TYPE_NONE;
> +	struct irq_fwspec *fwspec = arg;
> +
> +	ret = plic_irq_domain_translate(domain, fwspec, &hwirq, &type);
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < nr_irqs; i++) {
> +		ret = plic_irqdomain_map(domain, virq + i, hwirq + i);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static const struct irq_domain_ops plic_irqdomain_ops = {
> -	.map		= plic_irqdomain_map,
> -	.xlate		= irq_domain_xlate_onecell,
> +	.translate	= plic_irq_domain_translate,
> +	.alloc		= plic_irq_domain_alloc,
> +	.free		= irq_domain_free_irqs_top,
>  };
>
>  static struct irq_domain *plic_irqdomain;

Otherwise, looks OK.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...