Subject: [PATCH 05/11] irqchip / gic: Add stacked irqdomain support for ACPI based GICv2 init

From: [email-masked] (Marc Zyngier)
Date: Wed, 10 Jun 2015 17:27:02 +0100

On 18/05/15 13:59, Hanjun Guo wrote:
> Introduce acpi_irq_domain for GICv2 core domain instead of referring
> to the irq_default_domain, based on that, pass gsi as the argument and
> get the gsi in gic_irq_domain_alloc() to add stacked irqdomain support
> for ACPI based GICv2 init.
> 
> Signed-off-by: Hanjun Guo <[email-masked]>
> ---
>  drivers/acpi/gsi.c                   | 28 +++++++++++++---------------
>  drivers/irqchip/irq-gic.c            | 32 +++++++++++++++++---------------
>  include/linux/irqchip/arm-gic-acpi.h |  2 ++
>  3 files changed, 32 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/acpi/gsi.c b/drivers/acpi/gsi.c
> index 38208f2..55b5f31 100644
> --- a/drivers/acpi/gsi.c
> +++ b/drivers/acpi/gsi.c
> @@ -3,6 +3,7 @@
>   *
>   * Copyright (C) 2015 ARM Ltd.
>   * Author: Lorenzo Pieralisi <[email-masked]>
> + *         Hanjun Guo <[email-masked]> for stacked irqdomains support
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License version 2 as
> @@ -13,6 +14,8 @@
>  #include <linux/irqdomain.h>
>  
>  enum acpi_irq_model_id acpi_irq_model;
> +/* ACPI core domian pointing to GICv2/3 core domain */
> +struct irq_domain *acpi_irq_domain __read_mostly;

How is a single domain pointer going to work when you will have several
domains (GICv2m, ITS)? Crucially, how are you going to perform the
matching of a device with its irq domain?

	M.

>  
>  static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
>  {
> @@ -45,12 +48,7 @@ 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);
> +	*irq = irq_find_mapping(acpi_irq_domain, gsi);
>  	/*
>  	 * *irq == 0 means no mapping, that should
>  	 * be reported as a failure
> @@ -72,16 +70,16 @@ EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
>  int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
>  		      int polarity)
>  {
> -	unsigned int irq;
> +	int irq;
>  	unsigned int irq_type = acpi_gsi_get_irq_type(trigger, polarity);
>  
> -	/*
> -	 * 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
> -	 */
> -	irq = irq_create_mapping(NULL, gsi);
> -	if (!irq)
> +	irq = irq_find_mapping(acpi_irq_domain, gsi);
> +	if (irq > 0)
> +		return irq;
> +
> +	irq = irq_domain_alloc_irqs(acpi_irq_domain, 1, dev_to_node(dev),
> +				    &gsi);
> +	if (irq <= 0)
>  		return -EINVAL;
>  
>  	/* Set irq type if specified and different than the current one */
> @@ -98,7 +96,7 @@ EXPORT_SYMBOL_GPL(acpi_register_gsi);
>   */
>  void acpi_unregister_gsi(u32 gsi)
>  {
> -	int irq = irq_find_mapping(NULL, gsi);
> +	int irq = irq_find_mapping(acpi_irq_domain, gsi);
>  
>  	irq_dispose_mapping(irq);
>  }
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index fefbcb5..869a69f 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -851,15 +851,22 @@ static struct notifier_block gic_cpu_notifier = {
>  static int gic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
>  				unsigned int nr_irqs, void *arg)
>  {
> -	int i, ret;
> +	int i;
>  	irq_hw_number_t hwirq;
> -	unsigned int type = IRQ_TYPE_NONE;
> -	struct of_phandle_args *irq_data = arg;
>  
> -	ret = gic_irq_domain_xlate(domain, irq_data->np, irq_data->args,
> -				   irq_data->args_count, &hwirq, &type);
> -	if (ret)
> -		return ret;
> +	if (domain->of_node) {	/* DT case */
> +		int ret;
> +		unsigned int type = IRQ_TYPE_NONE;
> +		struct of_phandle_args *irq_data = arg;
> +
> +		ret = gic_irq_domain_xlate(domain, irq_data->np,
> +					irq_data->args,
> +					irq_data->args_count, &hwirq, &type);
> +		if (ret)
> +			return ret;
> +	} else {	/* ACPI case */
> +		hwirq = (irq_hw_number_t)*(u32 *)arg;
> +	}
>  
>  	for (i = 0; i < nr_irqs; i++)
>  		gic_irq_domain_map(domain, virq + i, hwirq + i);
> @@ -945,11 +952,11 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
>  		gic_irqs = 1020;
>  	gic->gic_irqs = gic_irqs;
>  
> -	if (node) {		/* DT case */
> +	if (node || !acpi_disabled) {		/* DT or ACPI case */
>  		gic->domain = irq_domain_add_linear(node, gic_irqs,
>  						    &gic_irq_domain_hierarchy_ops,
>  						    gic);
> -	} else {		/* Non-DT case */
> +	} else {		/* Non-DT and ACPI case */
>  		/*
>  		 * For primary GICs, skip over SGIs.
>  		 * For secondary GICs, skip over PPIs, too.
> @@ -1133,13 +1140,8 @@ gic_v2_acpi_init(struct acpi_table_header *table)
>  		return -ENOMEM;
>  	}
>  
> -	/*
> -	 * Initialize zero GIC instance (no multi-GIC support). Also, set GIC
> -	 * as default IRQ domain to allow for GSI registration and GSI to IRQ
> -	 * number translation (see acpi_register_gsi() and acpi_gsi_to_irq()).
> -	 */
>  	gic_init_bases(0, -1, dist_base, cpu_base, 0, NULL);
> -	irq_set_default_host(gic_data[0].domain);
> +	acpi_irq_domain = gic_data[0].domain;
>  
>  	acpi_irq_model = ACPI_IRQ_MODEL_GIC;
>  	return 0;
> diff --git a/include/linux/irqchip/arm-gic-acpi.h b/include/linux/irqchip/arm-gic-acpi.h
> index 021e8e8..245386d 100644
> --- a/include/linux/irqchip/arm-gic-acpi.h
> +++ b/include/linux/irqchip/arm-gic-acpi.h
> @@ -21,6 +21,8 @@
>  #define ACPI_GIC_CPU_IF_MEM_SIZE	(SZ_8K)
>  #define ACPI_GICV3_DIST_MEM_SIZE	(SZ_64K)
>  
> +extern struct irq_domain *acpi_irq_domain;
> +
>  int acpi_gic_version_init(void);
>  u8 acpi_gic_version(void);
>  #endif /* CONFIG_ACPI */
> 

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