Message-ID: <20170203090210.GC30745@red-moon>
Date:   Fri, 3 Feb 2017 09:02:10 +0000
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....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, andy.shevchenko@...il.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, guohanjun@...wei.com,
        charles.garcia-tobin@....com
Subject: Re: [PATCH V12 2/3] ACPI: Add support for ResourceSource/IRQ domain
 mapping

On Thu, Feb 02, 2017 at 06:23:58PM -0500, 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.
> 
> Acked-by: Rafael J. Wysocki <rafael@...nel.org>
> Signed-off-by: Agustin Vega-Frias <agustinv@...eaurora.org>
> ---
>  drivers/acpi/Makefile         |   2 +-
>  drivers/acpi/{gsi.c => irq.c} | 199 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/base/platform.c       |  10 +++
>  include/linux/acpi.h          |  10 +++
>  4 files changed, 220 insertions(+), 1 deletion(-)
>  rename drivers/acpi/{gsi.c => irq.c} (31%)

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>

> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 9ed0878..a391bbc 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -55,7 +55,7 @@ acpi-$(CONFIG_DEBUG_FS)		+= debugfs.o
>  acpi-$(CONFIG_ACPI_NUMA)	+= numa.o
>  acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o
>  acpi-y				+= acpi_lpat.o
> -acpi-$(CONFIG_ACPI_GENERIC_GSI) += gsi.o
> +acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
>  acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o
>  
>  # These are (potentially) separate modules
> diff --git a/drivers/acpi/gsi.c b/drivers/acpi/irq.c
> similarity index 31%
> rename from drivers/acpi/gsi.c
> rename to drivers/acpi/irq.c
> index ee9e0f2..830299a 100644
> --- a/drivers/acpi/gsi.c
> +++ b/drivers/acpi/irq.c
> @@ -85,6 +85,205 @@ void acpi_unregister_gsi(u32 gsi)
>  EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
>  
>  /**
> + * acpi_get_irq_source_fwhandle() - Retrieve fwhandle from IRQ resource source.
> + * @source: acpi_resource_source to use for the lookup.
> + *
> + * Description:
> + * Retrieve the fwhandle of the device referenced by the given IRQ resource
> + * source.
> + *
> + * Return:
> + * The referenced device fwhandle or NULL on failure
> + */
> +static struct fwnode_handle *
> +acpi_get_irq_source_fwhandle(const struct acpi_resource_source *source)
> +{
> +	struct fwnode_handle *result;
> +	struct acpi_device *device;
> +	acpi_handle handle;
> +	acpi_status status;
> +
> +	if (!source->string_length)
> +		return acpi_gsi_domain_id;
> +
> +	status = acpi_get_handle(NULL, source->string_ptr, &handle);
> +	if (WARN_ON(ACPI_FAILURE(status)))
> +		return NULL;
> +
> +	device = acpi_bus_get_acpi_device(handle);
> +	if (WARN_ON(!device))
> +		return NULL;
> +
> +	result = &device->fwnode;
> +	acpi_bus_put_acpi_device(device);
> +	return result;
> +}
> +
> +/*
> + * Context for the resource walk used to lookup IRQ resources.
> + * Contains a return code, the lookup index, and references to the flags
> + * and fwspec where the result is returned.
> + */
> +struct acpi_irq_parse_one_ctx {
> +	int rc;
> +	unsigned int index;
> +	unsigned long *res_flags;
> +	struct irq_fwspec *fwspec;
> +};
> +
> +/**
> + * acpi_irq_parse_one_match - Handle a matching IRQ resource.
> + * @fwnode: matching fwnode
> + * @hwirq: hardware IRQ number
> + * @triggering: triggering attributes of hwirq
> + * @polarity: polarity attributes of hwirq
> + * @polarity: polarity attributes of hwirq
> + * @shareable: shareable attributes of hwirq
> + * @ctx: acpi_irq_parse_one_ctx updated by this function
> + *
> + * Description:
> + * Handle a matching IRQ resource by populating the given ctx with
> + * the information passed.
> + */
> +static inline void acpi_irq_parse_one_match(struct fwnode_handle *fwnode,
> +					    u32 hwirq, u8 triggering,
> +					    u8 polarity, u8 shareable,
> +					    struct acpi_irq_parse_one_ctx *ctx)
> +{
> +	if (!fwnode)
> +		return;
> +	ctx->rc = 0;
> +	*ctx->res_flags = acpi_dev_irq_flags(triggering, polarity, shareable);
> +	ctx->fwspec->fwnode = fwnode;
> +	ctx->fwspec->param[0] = hwirq;
> +	ctx->fwspec->param[1] = acpi_dev_get_irq_type(triggering, polarity);
> +	ctx->fwspec->param_count = 2;
> +}
> +
> +/**
> + * acpi_irq_parse_one_cb - Handle the given resource.
> + * @ares: resource to handle
> + * @context: context for the walk
> + *
> + * Description:
> + * 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 (eirq->producer_consumer == ACPI_PRODUCER)
> +			return AE_OK;
> +		if (ctx->index >= eirq->interrupt_count) {
> +			ctx->index -= eirq->interrupt_count;
> +			return AE_OK;
> +		}
> +		fwnode = acpi_get_irq_source_fwhandle(&eirq->resource_source);
> +		acpi_irq_parse_one_match(fwnode, eirq->interrupts[ctx->index],
> +					 eirq->triggering, eirq->polarity,
> +					 eirq->sharable, ctx);
> +		return AE_CTRL_TERMINATE;
> +	}
> +
> +	return AE_OK;
> +}
> +
> +/**
> + * acpi_irq_parse_one - Resolve an interrupt for a device
> + * @handle: the device whose interrupt is to be resolved
> + * @index: index of the interrupt to resolve
> + * @fwspec: structure irq_fwspec filled by this function
> + * @flags: resource flags filled by this function
> + *
> + * Description:
> + * Resolves an interrupt for a device by walking its CRS resources to find
> + * the appropriate ACPI IRQ resource and populating the given struct irq_fwspec
> + * and flags.
> + *
> + * Return:
> + * The result stored in ctx.rc by the callback, or the default -EINVAL value
> + * if an error occurs.
> + */
> +static int acpi_irq_parse_one(acpi_handle handle, unsigned int index,
> +			      struct irq_fwspec *fwspec, unsigned long *flags)
> +{
> +	struct acpi_irq_parse_one_ctx ctx = { -EINVAL, index, flags, fwspec };
> +
> +	acpi_walk_resources(handle, METHOD_NAME__CRS, acpi_irq_parse_one_cb, &ctx);
> +	return ctx.rc;
> +}
> +
> +/**
> + * acpi_irq_get - Lookup an ACPI IRQ resource and use it to initialize resource.
> + * @handle: ACPI device handle
> + * @index:  ACPI IRQ resource index to lookup
> + * @res:    Linux IRQ resource to initialize
> + *
> + * Description:
> + * Look for the ACPI IRQ resource with the given index and use it to initialize
> + * the given Linux IRQ resource.
> + *
> + * Return:
> + * 0 on success
> + * -EINVAL if an error occurs
> + * -EPROBE_DEFER if the IRQ lookup/conversion failed
> + */
> +int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res)
> +{
> +	struct irq_fwspec fwspec;
> +	struct irq_domain *domain;
> +	unsigned long flags;
> +	int rc;
> +
> +	rc = acpi_irq_parse_one(handle, index, &fwspec, &flags);
> +	if (rc)
> +		return rc;
> +
> +	domain = irq_find_matching_fwnode(fwspec.fwnode, DOMAIN_BUS_ANY);
> +	if (!domain)
> +		return -EPROBE_DEFER;
> +
> +	rc = irq_create_fwspec_mapping(&fwspec);
> +	if (rc <= 0)
> +		return -EINVAL;
> +
> +	res->start = rc;
> +	res->end = rc;
> +	res->flags = flags;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(acpi_irq_get);
> +
> +/**
>   * acpi_set_irq_model - Setup the GSI irqdomain information
>   * @model: the value assigned to acpi_irq_model
>   * @fwnode: the irq_domain identifier for mapping and looking up
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index c4af003..647e476 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -102,6 +102,16 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
>  	}
>  
>  	r = platform_get_resource(dev, IORESOURCE_IRQ, num);
> +	if (has_acpi_companion(&dev->dev)) {
> +		if (r && r->flags & IORESOURCE_DISABLED) {
> +			int ret;
> +
> +			ret = acpi_irq_get(ACPI_HANDLE(&dev->dev), num, r);
> +			if (ret)
> +				return ret;
> +		}
> +	}
> +
>  	/*
>  	 * The resources may pass trigger flags to the irqs that need
>  	 * to be set up. It so happens that the trigger flags for
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 5b36974..8e577c2 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -1153,4 +1153,14 @@ static inline void acpi_table_upgrade(void) { }
>  static inline int parse_spcr(bool earlycon) { return 0; }
>  #endif
>  
> +#if IS_ENABLED(CONFIG_ACPI_GENERIC_GSI)
> +int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res);
> +#else
> +static inline
> +int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res)
> +{
> +	return -EINVAL;
> +}
> +#endif
> +
>  #endif	/*_LINUX_ACPI_H*/
> -- 
> Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm Technologies, Inc.
> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
> 

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