Re: [PATCH V10 2/3] ACPI: Add support for ResourceSource/IRQ domain mapping

From: Rafael J. Wysocki
Date: Tue Jan 31 2017 - 17:11:33 EST

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On Wed, Jan 18, 2017 at 5:46 PM, Agustin Vega-Frias
<agustinv@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> ---
> drivers/acpi/Makefile | 2 +-
> drivers/acpi/gsi.c | 98 -----------------
> drivers/acpi/irq.c | 282 ++++++++++++++++++++++++++++++++++++++++++++++++
> drivers/base/platform.c | 9 +-
> include/linux/acpi.h | 10 ++
> 5 files changed, 301 insertions(+), 100 deletions(-)
> delete mode 100644 drivers/acpi/gsi.c
> create mode 100644 drivers/acpi/irq.c
>
> 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/gsi.c
> deleted file mode 100644
> index ee9e0f2..0000000
> --- a/drivers/acpi/gsi.c
> +++ /dev/null
> @@ -1,98 +0,0 @@
> -/*
> - * ACPI GSI IRQ layer
> - *
> - * Copyright (C) 2015 ARM Ltd.
> - * Author: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> - *
> - * 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
> - * published by the Free Software Foundation.
> - */
> -#include <linux/acpi.h>
> -#include <linux/irq.h>
> -#include <linux/irqdomain.h>
> -#include <linux/of.h>
> -
> -enum acpi_irq_model_id acpi_irq_model;
> -
> -static struct fwnode_handle *acpi_gsi_domain_id;
> -
> -/**
> - * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
> - * @gsi: GSI IRQ number to map
> - * @irq: pointer where linux IRQ number is stored
> - *
> - * irq location updated with irq value [>0 on success, 0 on failure]
> - *
> - * Returns: linux IRQ number on success (>0)
> - * -EINVAL on failure
> - */
> -int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
> -{
> - struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> - DOMAIN_BUS_ANY);
> -
> - *irq = irq_find_mapping(d, gsi);
> - /*
> - * *irq == 0 means no mapping, that should
> - * be reported as a failure
> - */
> - return (*irq > 0) ? *irq : -EINVAL;
> -}
> -EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
> -
> -/**
> - * acpi_register_gsi() - Map a GSI to a linux IRQ number
> - * @dev: device for which IRQ has to be mapped
> - * @gsi: GSI IRQ number
> - * @trigger: trigger type of the GSI number to be mapped
> - * @polarity: polarity of the GSI to be mapped
> - *
> - * Returns: a valid linux IRQ number on success
> - * -EINVAL on failure
> - */
> -int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
> - int polarity)
> -{
> - struct irq_fwspec fwspec;
> -
> - if (WARN_ON(!acpi_gsi_domain_id)) {
> - pr_warn("GSI: No registered irqchip, giving up\n");
> - return -EINVAL;
> - }
> -
> - fwspec.fwnode = acpi_gsi_domain_id;
> - fwspec.param[0] = gsi;
> - fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
> - fwspec.param_count = 2;
> -
> - return irq_create_fwspec_mapping(&fwspec);
> -}
> -EXPORT_SYMBOL_GPL(acpi_register_gsi);
> -
> -/**
> - * acpi_unregister_gsi() - Free a GSI<->linux IRQ number mapping
> - * @gsi: GSI IRQ number
> - */
> -void acpi_unregister_gsi(u32 gsi)
> -{
> - struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> - DOMAIN_BUS_ANY);
> - int irq = irq_find_mapping(d, 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
> - * @fwnode: the irq_domain identifier for mapping and looking up
> - * GSI interrupts
> - */
> -void __init acpi_set_irq_model(enum acpi_irq_model_id model,
> - struct fwnode_handle *fwnode)
> -{
> - acpi_irq_model = model;
> - acpi_gsi_domain_id = fwnode;
> -}
> diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
> new file mode 100644
> index 0000000..cadc4cdd
> --- /dev/null
> +++ b/drivers/acpi/irq.c
> @@ -0,0 +1,282 @@
> +/*
> + * ACPI GSI IRQ layer
> + *
> + * Copyright (C) 2015 ARM Ltd.
> + * Author: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> + *
> + * 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
> + * published by the Free Software Foundation.
> + */
> +#include <linux/acpi.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/of.h>
> +
> +enum acpi_irq_model_id acpi_irq_model;
> +
> +static struct fwnode_handle *acpi_gsi_domain_id;
> +
> +/**
> + * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
> + * @gsi: GSI IRQ number to map
> + * @irq: pointer where linux IRQ number is stored
> + *
> + * irq location updated with irq value [>0 on success, 0 on failure]
> + *
> + * Returns: linux IRQ number on success (>0)
> + * -EINVAL on failure
> + */
> +int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
> +{
> + struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> + DOMAIN_BUS_ANY);
> +
> + *irq = irq_find_mapping(d, gsi);
> + /*
> + * *irq == 0 means no mapping, that should
> + * be reported as a failure
> + */
> + return (*irq > 0) ? *irq : -EINVAL;
> +}
> +EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
> +
> +/**
> + * acpi_register_gsi() - Map a GSI to a linux IRQ number
> + * @dev: device for which IRQ has to be mapped
> + * @gsi: GSI IRQ number
> + * @trigger: trigger type of the GSI number to be mapped
> + * @polarity: polarity of the GSI to be mapped
> + *
> + * Returns: a valid linux IRQ number on success
> + * -EINVAL on failure
> + */
> +int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
> + int polarity)
> +{
> + struct irq_fwspec fwspec;
> +
> + if (WARN_ON(!acpi_gsi_domain_id)) {
> + pr_warn("GSI: No registered irqchip, giving up\n");
> + return -EINVAL;
> + }
> +
> + fwspec.fwnode = acpi_gsi_domain_id;
> + fwspec.param[0] = gsi;
> + fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
> + fwspec.param_count = 2;
> +
> + return irq_create_fwspec_mapping(&fwspec);
> +}
> +EXPORT_SYMBOL_GPL(acpi_register_gsi);
> +
> +/**
> + * acpi_unregister_gsi() - Free a GSI<->linux IRQ number mapping
> + * @gsi: GSI IRQ number
> + */
> +void acpi_unregister_gsi(u32 gsi)
> +{
> + struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> + DOMAIN_BUS_ANY);
> + int irq = irq_find_mapping(d, gsi);
> +
> + irq_dispose_mapping(irq);
> +}
> +EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
> +
> +/**
> + * acpi_get_irq_source_fwhandle() - Retrieve the fwhandle of the given
> + * acpi_resource_source which is used
> + * as an IRQ domain id
> + * @source: acpi_resource_source to use for the lookup
> + *
> + * Returns: The appropriate IRQ fwhandle domain id
> + * 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 (ACPI_FAILURE(status)) {
> + pr_warn("Could not find handle for %s\n", source->string_ptr);
> + return NULL;
> + }
> +
> + device = acpi_bus_get_acpi_device(handle);
> + if (!device) {
> + pr_warn("Could not get device for %s\n", source->string_ptr);
> + return NULL;
> + }
> +
> + result = &device->fwnode;
> + acpi_bus_put_acpi_device(device);
> +
> + return result;
> +}
> +
> +/**
> + * Context for the resource walk used to lookup IRQ resources.
> + */
> +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
> + */
> +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)
> +{
> + 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, 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 (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
> + *
> + * This function resolves an interrupt for a device by walking its CRS resources
> + * to find the appropriate ACPI IRQ resource and populating the given structure
> + * which can be used to retrieve a Linux IRQ number.
> + *
> + * Returns the result stored in ctx.rc by the callback, or -EINVAL if the given
> + * index is out of range.
> + */
> +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_status status;
> +
> + status = acpi_walk_resources(handle, METHOD_NAME__CRS,
> + acpi_irq_parse_one_cb, &ctx);
> + if (ACPI_FAILURE(status))
> + return -EINVAL;
> + return ctx.rc;
> +}
> +
> +/**
> + * acpi_irq_get - Look for the ACPI IRQ resource with the given index and
> + * use it to initialize the given Linux IRQ resource.
> + * @handle ACPI device handle
> + * @index ACPI IRQ resource index to lookup
> + * @res Linux IRQ resource to initialize
> + *
> + * 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)
> +{
> + int rc;
> + struct irq_fwspec fwspec;
> + struct irq_domain *domain;
> + unsigned long flags;
> +
> + 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
> + * GSI interrupts
> + */
> +void __init acpi_set_irq_model(enum acpi_irq_model_id model,
> + struct fwnode_handle *fwnode)
> +{
> + acpi_irq_model = model;
> + acpi_gsi_domain_id = fwnode;
> +}
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index c4af003..61423d2 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -102,6 +102,14 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
> }
>
> r = platform_get_resource(dev, IORESOURCE_IRQ, num);
> + if (r && r->flags & IORESOURCE_DISABLED && ACPI_COMPANION(&dev->dev)) {
> + int ret;
> +
> + ret = acpi_irq_get(ACPI_HANDLE(&dev->dev), num, r);
> + if (ret)
> + return ret;
> + }

The code above is a bit convoluted. It would be better to write it as
something like

if (r && r->flags & IORESOURCE_DISABLED) {
struct acpi_device *adev = ACPI_COMPANION(&dev->dev);

if (adev) {
int ret = acpi_irq_get(adev->handle, 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
> @@ -1450,4 +1458,3 @@ void __init early_platform_cleanup(void)
> memset(&pd->dev.devres_head, 0, sizeof(pd->dev.devres_head));
> }
> }
> -
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 5b36974..03a94cd 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
>
> +#ifdef 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*/

The rest looks reasonable to me.

Thanks,
Rafael

Next message: Tejun Heo: "Re: [GIT PULL] percpu fix for v4.10-rc6"
Previous message: Guenter Roeck: "Re: [PATCH] r8152: Allocate interrupt buffer as part of struct r8152"
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