linux-kernel - Re: [PATCH 4/5] acpi: gsi: Use acpi_gsi

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Message-ID: <20150721181646.GC32187@red-moon>
Date:	Tue, 21 Jul 2015 19:16:46 +0100
From:	Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:	Marc Zyngier <marc.zyngier@....com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Jiang Liu <jiang.liu@...ux.intel.com>,
	Jason Cooper <jason@...edaemon.net>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Tomasz Nowicki <tomasz.nowicki@...aro.org>,
	"hanjun.guo@...aro.org" <hanjun.guo@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"suravee.suthikulpanit@....com" <suravee.suthikulpanit@....com>
Subject: Re: [PATCH 4/5] acpi: gsi: Use acpi_gsi_descriptor to allocate
 interrupts

On Tue, Jul 21, 2015 at 11:07:59AM +0100, Marc Zyngier wrote:
> Now that the irqdomain layer is a bit more ACPI friendly, add the
> mapping code that allows irq_create_acpi_mapping to be called.
> 
> As we only support the GIC so far, support is pretty limited.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@....com>
> ---
>  drivers/acpi/gsi.c | 54 ++++++++++++++++++++++++++++++++++++------------------
>  1 file changed, 36 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/acpi/gsi.c b/drivers/acpi/gsi.c
> index 38208f2..005d843 100644
> --- a/drivers/acpi/gsi.c
> +++ b/drivers/acpi/gsi.c
> @@ -33,6 +33,12 @@ static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
>  	}
>  }
>  
> +static struct irq_domain *irq_find_acpi_domain(enum acpi_irq_model_id id,
> +					       enum irq_domain_bus_token bus_token)
> +{
> +	return irq_find_matching_host((void *)id, bus_token);
> +}
> +
>  /**
>   * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
>   * @gsi: GSI IRQ number to map
> @@ -45,12 +51,10 @@ static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
>   */
>  int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
>  {
> -	/*
> -	 * Only default domain is supported at present, always find
> -	 * the mapping corresponding to default domain by passing NULL
> -	 * as irq_domain parameter
> -	 */
> -	*irq = irq_find_mapping(NULL, gsi);
> +	struct irq_domain *d = irq_find_acpi_domain(acpi_irq_model,
> +						    DOMAIN_BUS_ANY);
> +
> +	*irq = irq_find_mapping(d, gsi);
>  	/*
>  	 * *irq == 0 means no mapping, that should
>  	 * be reported as a failure
> @@ -72,23 +76,35 @@ EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
>  int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
>  		      int polarity)
>  {
> -	unsigned int irq;
> +	struct acpi_gsi_descriptor data;
>  	unsigned int irq_type = acpi_gsi_get_irq_type(trigger, polarity);
> +	struct irq_domain *d = irq_find_acpi_domain(acpi_irq_model,
> +						    DOMAIN_BUS_ANY);
>  
>  	/*
> -	 * There is no way at present to look-up the IRQ domain on ACPI,
> -	 * hence always create mapping referring to the default domain
> -	 * by passing NULL as irq_domain parameter
> +	 * Populate the GSI descriptor in a way that matches the way
> +	 * the driver expects its of_phandle_args.
>  	 */
> -	irq = irq_create_mapping(NULL, gsi);
> -	if (!irq)
> +	switch (acpi_irq_model) {
> +	case ACPI_IRQ_MODEL_GIC:
> +		if (gsi >= 32) {
> +			data.param[0] = 0;
> +			data.param[1] = gsi - 32;
> +			data.param[2] = irq_type;
> +		} else {
> +			data.param[0] = 1;
> +			data.param[1] = gsi - 16;
> +			data.param[2] = 0xff << 4 | irq_type;
> +		}
> +
> +		data.param_count = 3;
> +		break;
> +	default:
> +		pr_warn("Unknown acpi_irq_model = %d\n", acpi_irq_model);
>  		return -EINVAL;
> +	}

Nit: you could move the switch in a function (in this file) so that
code that is irq model specific is self-contained and in a function
on its own, if we ever have to add other irq models later I think it
is easier to parse.

Lorenzo

>  
> -	/* Set irq type if specified and different than the current one */
> -	if (irq_type != IRQ_TYPE_NONE &&
> -		irq_type != irq_get_trigger_type(irq))
> -		irq_set_irq_type(irq, irq_type);
> -	return irq;
> +	return irq_create_acpi_mapping(d, &data);
>  }
>  EXPORT_SYMBOL_GPL(acpi_register_gsi);
>  
> @@ -98,7 +114,9 @@ EXPORT_SYMBOL_GPL(acpi_register_gsi);
>   */
>  void acpi_unregister_gsi(u32 gsi)
>  {
> -	int irq = irq_find_mapping(NULL, gsi);
> +	struct irq_domain *d = irq_find_acpi_domain(acpi_irq_model,
> +						    DOMAIN_BUS_ANY);
> +	int irq = irq_find_mapping(d, gsi);
>  
>  	irq_dispose_mapping(irq);
>  }
> -- 
> 2.1.4
> 
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