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    Subject[PATCH V9 2/3] ACPI: Add support for ResourceSource/IRQ domain mapping
    Date
    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@codeaurora.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%)

    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 32%
    rename from drivers/acpi/gsi.c
    rename to drivers/acpi/irq.c
    index ee9e0f2..133d3f8 100644
    --- a/drivers/acpi/gsi.c
    +++ b/drivers/acpi/irq.c
    @@ -85,6 +85,188 @@ void acpi_unregister_gsi(u32 gsi)
    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 (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
    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 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 61a3d90..2284fc6 100644
    --- a/include/linux/acpi.h
    +++ b/include/linux/acpi.h
    @@ -1123,4 +1123,14 @@ 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*/
    --
    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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