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

From: Rafael J. Wysocki
Date: Wed Jun 26 2024 - 15:22:12 EST


On Mon, May 6, 2024 at 7:48 PM John Allen <john.allen@xxxxxxx> 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@xxxxxxx>
> Reviewed-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
> ---
> 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@xxxxxxxxx>

> ---
> 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
>