linux-kernel - Re: [PATCH v2 1/2] ACPI: PRM: Add PRM handler direct call support

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Message-ID: <CAJZ5v0hAnQvBo0vyCwXC=NysA+HTrMi_45hKBdk+xTy5KUZMMA@mail.gmail.com>
Date: Wed, 26 Jun 2024 21:21:49 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: John Allen <john.allen@....com>
Cc: rafael@...nel.org, lenb@...nel.org, bp@...en8.de, yazen.ghannam@....com, 
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-edac@...r.kernel.org
Subject: Re: [PATCH v2 1/2] ACPI: PRM: Add PRM handler direct call support

On Mon, May 6, 2024 at 7:48 PM John Allen <john.allen@....com> wrote:
>
> Platform Runtime Mechanism (PRM) handlers can be invoked from either the
> AML interpreter or directly by an OS driver. Implement the direct call
> method.
>
> Export the symbol as this will be used by modules such as the AMD
> Address Translation Library and likely others in the future.
>
> Signed-off-by: John Allen <john.allen@....com>
> Reviewed-by: Yazen Ghannam <yazen.ghannam@....com>
> ---
> v2:
>   - Align statements setting fields in context buffer on '='

I would actually prefer spaces around the "=" there, but anyway

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

> ---
>  drivers/acpi/prmt.c  | 24 ++++++++++++++++++++++++
>  include/linux/prmt.h |  5 +++++
>  2 files changed, 29 insertions(+)
>
> diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> index c78453c74ef5..1cfaa5957ac4 100644
> --- a/drivers/acpi/prmt.c
> +++ b/drivers/acpi/prmt.c
> @@ -214,6 +214,30 @@ static struct prm_handler_info *find_prm_handler(const guid_t *guid)
>  #define UPDATE_LOCK_ALREADY_HELD       4
>  #define UPDATE_UNLOCK_WITHOUT_LOCK     5
>
> +int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
> +{
> +       struct prm_handler_info *handler = find_prm_handler(&handler_guid);
> +       struct prm_module_info *module = find_prm_module(&handler_guid);
> +       struct prm_context_buffer context;
> +       efi_status_t status;
> +
> +       if (!module || !handler)
> +               return -ENODEV;
> +
> +       memset(&context, 0, sizeof(context));
> +       ACPI_COPY_NAMESEG(context.signature, "PRMC");
> +       context.identifier         = handler->guid;
> +       context.static_data_buffer = handler->static_data_buffer_addr;
> +       context.mmio_ranges        = module->mmio_info;
> +
> +       status = efi_call_acpi_prm_handler(handler->handler_addr,
> +                                          (u64)param_buffer,
> +                                          &context);
> +
> +       return efi_status_to_err(status);
> +}
> +EXPORT_SYMBOL_GPL(acpi_call_prm_handler);
> +
>  /*
>   * This is the PlatformRtMechanism opregion space handler.
>   * @function: indicates the read/write. In fact as the PlatformRtMechanism
> diff --git a/include/linux/prmt.h b/include/linux/prmt.h
> index 24da8364b919..9c094294403f 100644
> --- a/include/linux/prmt.h
> +++ b/include/linux/prmt.h
> @@ -2,6 +2,11 @@
>
>  #ifdef CONFIG_ACPI_PRMT
>  void init_prmt(void);
> +int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer);
>  #else
>  static inline void init_prmt(void) { }
> +static inline int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
> +{
> +       return -EOPNOTSUPP;
> +}
>  #endif
> --
> 2.34.1
>