linux-kernel - Re: [PATCH v2 5/7] acpi: gsi: Add acpi_set_irq

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Message-ID: <55B22F16.3040206@arm.com>
Date:	Fri, 24 Jul 2015 13:27:02 +0100
From:	Marc Zyngier <marc.zyngier@....com>
To:	Hanjun Guo <hanjun.guo@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jiang Liu <jiang.liu@...ux.intel.com>,
	Jason Cooper <jason@...edaemon.net>
CC:	"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>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Tomasz Nowicki <tomasz.nowicki@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"suravee.suthikulpanit@....com" <suravee.suthikulpanit@....com>,
	Graeme Gregory <graeme@...a.org.uk>
Subject: Re: [PATCH v2 5/7] acpi: gsi: Add acpi_set_irq_model to initialize
 the GSI layer

On 24/07/15 11:00, Hanjun Guo wrote:
> On 07/23/2015 09:05 PM, Marc Zyngier wrote:
>> In order to start embrassing irqdomains at the GSI level, introduce
>> a new initializer:
>>
>> void acpi_set_irq_model(enum acpi_irq_model_id model,
>> 			unsigned long domain_token,
>> 			int (*populate)(struct acpi_gsi_descriptor *,
>> 					u32, unsigned int));
>>
>> where:
>> - model is the value assigned to acpi_irq_model
>> - domain_token is the identifier for the irqdomain mapping
>>    GSI interrupts
>> - populate is a function provided by the interrupt controller,
>>    populating a struct acpi_gsi_descriptor based on a GSI and
>>    the interrupt trigger information
>>
>> As nobody calls this code yet, the current code is left in place.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@....com>
>> ---
>>   drivers/acpi/gsi.c   | 32 ++++++++++++++++++++++++++++++++
>>   include/linux/acpi.h |  5 +++++
>>   2 files changed, 37 insertions(+)
>>
>> diff --git a/drivers/acpi/gsi.c b/drivers/acpi/gsi.c
>> index a745880..e6f4a0c 100644
>> --- a/drivers/acpi/gsi.c
>> +++ b/drivers/acpi/gsi.c
>> @@ -16,6 +16,9 @@ enum acpi_irq_model_id acpi_irq_model;
>>
>>   static void *acpi_gsi_domain_token;
>>
>> +static int (*acpi_gsi_descriptor_populate)(struct acpi_gsi_descriptor *data,
>> +					   u32 gsi, unsigned int irq_type);
>> +
>>   static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
>>   {
>>   	switch (polarity) {
>> @@ -71,10 +74,20 @@ EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
>>   int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
>>   		      int polarity)
>>   {
>> +	int err;
>>   	unsigned int irq;
>>   	unsigned int irq_type = acpi_gsi_get_irq_type(trigger, polarity);
>>   	struct irq_domain *d = irq_find_host(acpi_gsi_domain_token);
>>
>> +	if (acpi_gsi_descriptor_populate) {
>> +		struct acpi_gsi_descriptor data;
>> +		err = acpi_gsi_descriptor_populate(&data, gsi, irq_type);
>> +		if (err)
>> +			return err;
>> +
>> +		return irq_create_acpi_mapping(d, &data);
>> +	}
>> +
>>   	irq = irq_create_mapping(d, gsi);
>>   	if (!irq)
>>   		return -EINVAL;
>> @@ -99,3 +112,22 @@ void acpi_unregister_gsi(u32 gsi)
>>   	irq_dispose_mapping(irq);
>>   }
>>   EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
>> +
>> +/**
>> + * acpi_set_irq_model - Setup the GSI irqdomain information
>> + * @model: the value assigned to acpi_irq_model
>> + * @domain_token: the irq_domain identifier for mapping and looking up
>> + *                GSI interrupts
>> + * @populate: provided by the interrupt controller, populating a
>> + *            struct acpi_gsi_descriptor based on a GSI and
>> + *            the interrupt trigger information
>> + */
>> +void acpi_set_irq_model(enum acpi_irq_model_id model,
>> +			unsigned long domain_token,
>> +			int (*populate)(struct acpi_gsi_descriptor *,
>> +					u32, unsigned int))
>> +{
>> +	acpi_irq_model = model;
>> +	acpi_gsi_domain_token = (void *)domain_token;
> 
> This will work perfectly fine with ARM as it has single GICD and
> one irq domain, I'm not sure x86 is ok with it because x86 has
> multi ioapics and each ioapic has a irqdomain if I understand
> correctly, but x86 don't use functions in this file at all for now,
> I think I'm over worried :)

When (and if) that day comes, we'll have to either contextualize
acpi_register_gsi to take a domain token, or have a lookup table that
maps GSI ranges to domain tokens.

Either way, this doesn't invalidate what is being done here.

Thanks,

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