Re: [PATCH v24 08/11] acpi: Introduce acpi_unregister_irq function

[Mark Rutland <mark.rutland@arm.com>]

On Sat, Apr 15, 2017 at 02:40:11AM +0800, fu.wei@linaro.org wrote:
> From: Fu Wei <fu.wei@linaro.org>
> 
> This patch introduces acpi_unregister_irq function to free a
> linux IRQ number<->GSI mapping by a given linux IRQ number.
> 
> Even we have successfully registered the GSI, when some error occurs, we
> may need to unmap it for freeing the IRQ resource. But in some cases, we
> only have IRQ, but not GSI.
> 
> This patch is the preparation for memory-mapped timer support in GTDT
> driver.
> 
> Signed-off-by: Fu Wei <fu.wei@linaro.org>
> ---
>  drivers/acpi/irq.c   | 10 ++++++++++
>  include/linux/acpi.h |  7 +++++++
>  2 files changed, 17 insertions(+)

This will need comments/acks from the ACPI folk.

Lorenzo, do you prefer this to direct use of irq_dispose_mapping() in
the GTDT parsing code?

Thanks,
Mark.

> diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
> index 830299a..59de777 100644
> --- a/drivers/acpi/irq.c
> +++ b/drivers/acpi/irq.c
> @@ -85,6 +85,16 @@ void acpi_unregister_gsi(u32 gsi)
>  EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
>  
>  /**
> + * acpi_unregister_irq() - Free a linux IRQ number<->GSI mapping
> + * @irq: linux IRQ number
> + */
> +void acpi_unregister_irq(int irq)
> +{
> +	irq_dispose_mapping(irq);
> +}
> +EXPORT_SYMBOL_GPL(acpi_unregister_irq);
> +
> +/**
>   * acpi_get_irq_source_fwhandle() - Retrieve fwhandle from IRQ resource source.
>   * @source: acpi_resource_source to use for the lookup.
>   *
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 4b5c146..728d1ed 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -336,6 +336,13 @@ extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
>   */
>  void acpi_unregister_gsi (u32 gsi);
>  
> +/*
> + * This function undoes the effect of one call to acpi_register_gsi().
> + * The irq should be the return value of acpi_register_gsi().
> + * If the irq is valid, free a linux IRQ number<->GSI mapping.
> + */
> +void acpi_unregister_irq(int irq);
> +
>  struct pci_dev;
>  
>  int acpi_pci_irq_enable (struct pci_dev *dev);
> -- 
> 2.9.3
>