linux-kernel - Re: [PATCH V9 2/3] ACPI: Add support for ResourceSource/IRQ domain mapping

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Date:   Wed, 18 Jan 2017 09:40:35 +0800
From:   Hanjun Guo <guohanjun@...wei.com>
To:     Agustin Vega-Frias <agustinv@...eaurora.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-acpi@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <rjw@...ysocki.net>,
        <lenb@...nel.org>, <tglx@...utronix.de>, <jason@...edaemon.net>,
        <marc.zyngier@....com>, <lorenzo.pieralisi@....com>,
        <timur@...eaurora.org>, <cov@...eaurora.org>,
        <agross@...eaurora.org>, <harba@...eaurora.org>, <jcm@...hat.com>,
        <msalter@...hat.com>, <mlangsdo@...hat.com>, <ahs3@...hat.com>,
        <astone@...hat.com>, <graeme.gregory@...aro.org>,
        <charles.garcia-tobin@....com>
Subject: Re: [PATCH V9 2/3] ACPI: Add support for ResourceSource/IRQ domain
 mapping

On 2017/1/17 23:07, Agustin Vega-Frias wrote:
> Hi Hanjun,
>
> On 2017-01-17 07:47, Hanjun Guo wrote:
>> On 2016/12/15 6:10, Agustin Vega-Frias wrote:
>>> ACPI extended IRQ resources may contain a ResourceSource to specify
>>> an alternate interrupt controller. Introduce acpi_irq_get and use it
>>> to implement ResourceSource/IRQ domain mapping.
>>>
>>> The new API is similar to of_irq_get and allows re-initialization
>>> of a platform resource from the ACPI extended IRQ resource, and
>>> provides proper behavior for probe deferral when the domain is not
>>> yet present when called.
>>>
>>> Signed-off-by: Agustin Vega-Frias <agustinv@...eaurora.org>
>>> ---
>>>  drivers/acpi/Makefile         |   2 +-
>>>  drivers/acpi/{gsi.c => irq.c} | 182 ++++++++++++++++++++++++++++++++++++++++++
>>>  drivers/base/platform.c       |   9 ++-
>>>  include/linux/acpi.h          |  10 +++
>>>  4 files changed, 201 insertions(+), 2 deletions(-)
>>>  rename drivers/acpi/{gsi.c => irq.c} (32%)
>>>
>> [...]
>>> +/**
>>> + * acpi_irq_parse_one_cb - Handle the given resource
>>> + * @ares: resource to handle
>>> + * @context: context for the walk, contains the lookup index and references
>>> + *           to the flags and fwspec where the result is returned
>>> + *
>>> + * This is called by acpi_walk_resources passing each resource returned by
>>> + * the _CRS method. We only inspect IRQ resources. Since IRQ resources
>>> + * might contain multiple interrupts we check if the index is within this
>>> + * one's interrupt array, otherwise we subtract the current resource IRQ
>>> + * count from the lookup index to prepare for the next resource.
>>> + * Once a match is found we call acpi_irq_parse_one_match to populate
>>> + * the result and end the walk by returning AE_CTRL_TERMINATE.
>>> + *
>>> + * Return AE_OK if the walk should continue, AE_CTRL_TERMINATE if a matching
>>> + * IRQ resource was found.
>>> + */
>>> +static acpi_status acpi_irq_parse_one_cb(struct acpi_resource *ares,
>>> +                     void *context)
>>> +{
>>> +    struct acpi_irq_parse_one_ctx *ctx = context;
>>> +    struct acpi_resource_irq *irq;
>>> +    struct acpi_resource_extended_irq *eirq;
>>> +    struct fwnode_handle *fwnode;
>>> +
>>> +    switch (ares->type) {
>>> +    case ACPI_RESOURCE_TYPE_IRQ:
>>> +        irq = &ares->data.irq;
>>> +        if (ctx->index >= irq->interrupt_count) {
>>> +            ctx->index -= irq->interrupt_count;
>>> +            return AE_OK;
>>> +        }
>>> +        fwnode = acpi_gsi_domain_id;
>>> +        acpi_irq_parse_one_match(fwnode, irq->interrupts[ctx->index],
>>> +                     irq->triggering, irq->polarity,
>>> +                     irq->sharable, ctx);
>>> +        return AE_CTRL_TERMINATE;
>>> +    case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
>>> +        eirq = &ares->data.extended_irq;
>>
>> If it's an interrupt producer, I think we don't need to map the interrupts in
>> any irqdomain, and return AE_CTRL_TERMINATE here.
>>
>>         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
>>                 eirq = &ares->data.extended_irq;
>> +         if (eirq->producer_consumer == ACPI_PRODUCER)
>> +                 return AE_CTRL_TERMINATE;
>>                 if (ctx->index >= eirq->interrupt_count) {
>
> Agreed. I'll add the check. However, we need to return AE_OK, not
> AE_CTRL_TERMINATE, since that terminates the walk and there might
> be other resources to check after this one.

Yes, thanks for the correction, there might be other Interrupt()
resources under _CRS which needs to be scanned.

Thanks
Hanjun