Subject: [PATCH v2 6/9] irqchip / gic: Add stacked irqdomain support for ACPI based GICv2 init

From: [email-masked] (Hanjun Guo)
Date: Tue, 23 Jun 2015 23:11:38 +0800

On 06/23/2015 01:20 AM, Lorenzo Pieralisi wrote:
> On Fri, Jun 19, 2015 at 09:46:09AM +0100, 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.
>
> This commit log does not parse and we can read the code, there is no
> point in trying to rewrite it here.
>
>> 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 */
>
> This code is not GIC specific and does not have to be.
>
>> +struct irq_domain *acpi_irq_domain __read_mostly;
>
> Make it static and create helpers to set it.
>
>>   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 8fc67bc..d1b2131 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;
>> +	}
>
> If domain->of_node is NULL and system booted with DT the code above
> does not fail (and if it fails almost certainly that won't be graceful)
> but it should.

how about the following logic?

if (!domain->of_node && acpi_disabled)
	return -ENODEV;
else if (domain->of_node)
	dt related code;
else
	ACPI related code;

>
>>   	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.
>> @@ -1130,13 +1137,8 @@ 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 56cd82c..a4a5edb 100644
>> --- a/include/linux/irqchip/arm-gic-acpi.h
>> +++ b/include/linux/irqchip/arm-gic-acpi.h
>> @@ -21,5 +21,7 @@
>>   #define ACPI_GIC_CPU_IF_MEM_SIZE	(SZ_8K)
>>   #define ACPI_GICV3_DIST_MEM_SIZE	(SZ_64K)
>>
>> +extern struct irq_domain *acpi_irq_domain;
>> +
>
> This declaration does not belong here, see above.

will update in next version.

Thanks
Hanjun