Re: [PATCH v4 1/6] ACPI: Add an interface to evaluate _OST

[Shuah Khan <shuahkhan@gmail.com>]

On Wed, 2012-05-23 at 20:25 -0600, Toshi Kani wrote:
> Added acpi_evaluate_hotplug_opt(). All ACPI hotplug handlers must call
> this function when evaluating _OST for hotplug operations. If the
> platform does not support _OST, this function returns AE_NOT_FOUND and
> has no effect on the platform.
> 
> ACPI_HOTPLUG_OST is defined when all relevant ACPI hotplug operations,
> such as CPU, memory and container hotplug, are enabled. This assures
> consistent behavior among the hotplug operations with regarding the
> _OST support. When ACPI_HOTPLUG_OST is not defined, this function is
> a no-op.
> 
> ACPI PCI hotplug is not enhanced to support _OST at this time since it
> is a legacy method being replaced by PCIe native hotplug. _OST support
> for ACPI PCI hotplug may be added in future if necessary.
> 
> Some platforms may require the OS to support _OST in order to support
> ACPI hotplug operations. For example, if a platform has the management
> console where user can request a hotplug operation from, this _OST
> support would be required for the management console to show the result
> of the hotplug request to user.
> 
> Added macro definitions of _OST source events and status codes.
> Also renamed OSC_SB_CPUHP_OST_SUPPORT to OSC_SB_HOTPLUG_OST_SUPPORT
> since this _OSC bit is not specific to CPU hotplug. This bit is
> defined in Table 6-147 of ACPI 5.0 as follows.
> 
>   Bits:       3
>   Field Name: Insertion / Ejection _OST Processing Support
>   Definition: This bit is set if OSPM will evaluate the _OST
>               object defined under a device when processing
>               insertion and ejection source event codes.
> 
> Signed-off-by: Toshi Kani <toshi.kani@hp.com>
> ---
>  drivers/acpi/utils.c    |   42 ++++++++++++++++++++++++++++++++++++++++++
>  include/acpi/acpi_bus.h |    3 +++
>  include/linux/acpi.h    |   40 +++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 84 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
> index adbbc1c..3e87c9c 100644
> --- a/drivers/acpi/utils.c
> +++ b/drivers/acpi/utils.c
> @@ -412,3 +412,45 @@ out:
>  	return status;
>  }
>  EXPORT_SYMBOL(acpi_get_physical_device_location);
> +
> +/**
> + * acpi_evaluate_hotplug_ost: Evaluate _OST for hotplug operations
> + * @handle: ACPI device handle
> + * @source_event: source event code
> + * @status_code: status code
> + * @status_buf: optional detailed information (NULL if none)
> + *
> + * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
> + * must call this function when evaluating _OST for hotplug operations.
> + * When the platform does not support _OST, this function has no effect.
> + */
> +acpi_status
> +acpi_evaluate_hotplug_ost(acpi_handle handle, u32 source_event,
> +		u32 status_code, struct acpi_buffer *status_buf)
> +{
> +#ifdef ACPI_HOTPLUG_OST
> +	union acpi_object params[3] = {
> +		{.type = ACPI_TYPE_INTEGER,},
> +		{.type = ACPI_TYPE_INTEGER,},
> +		{.type = ACPI_TYPE_BUFFER,}
> +	};
> +	struct acpi_object_list arg_list = {3, params};
> +	acpi_status status;
> +
> +	params[0].integer.value = source_event;
> +	params[1].integer.value = status_code;
> +	if (status_buf != NULL) {
> +		params[2].buffer.pointer = status_buf->pointer;
> +		params[2].buffer.length = status_buf->length;
> +	} else {
> +		params[2].buffer.pointer = NULL;
> +		params[2].buffer.length = 0;
> +	}
> +
> +	status = acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
> +	return status;
> +#else
> +	return AE_OK;
> +#endif
> +}
> +EXPORT_SYMBOL(acpi_evaluate_hotplug_ost);
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index b0d6282..1139f3a 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -50,6 +50,9 @@ acpi_evaluate_reference(acpi_handle handle,
>  			acpi_string pathname,
>  			struct acpi_object_list *arguments,
>  			struct acpi_handle_list *list);
> +acpi_status
> +acpi_evaluate_hotplug_ost(acpi_handle handle, u32 source_event,
> +			u32 status_code, struct acpi_buffer *status_buf);
>  
>  struct acpi_pld {
>  	unsigned int revision:7; /* 0 */
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index f421dd8..b2b4d2a 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -277,7 +277,7 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context);
>  #define OSC_SB_PAD_SUPPORT		1
>  #define OSC_SB_PPC_OST_SUPPORT		2
>  #define OSC_SB_PR3_SUPPORT		4
> -#define OSC_SB_CPUHP_OST_SUPPORT	8
> +#define OSC_SB_HOTPLUG_OST_SUPPORT	8
>  #define OSC_SB_APEI_SUPPORT		16
>  
>  extern bool osc_sb_apei_support_acked;
> @@ -309,6 +309,44 @@ extern bool osc_sb_apei_support_acked;
>  
>  extern acpi_status acpi_pci_osc_control_set(acpi_handle handle,
>  					     u32 *mask, u32 req);
> +
> +/* Enable _OST when all relevant hotplug operations are enabled */
> +#if defined(CONFIG_ACPI_HOTPLUG_CPU) &&			\
> +	(defined(CONFIG_ACPI_HOTPLUG_MEMORY) ||		\
> +	 defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)) &&	\
> +	(defined(CONFIG_ACPI_CONTAINER) ||		\
> +	 defined(CONFIG_ACPI_CONTAINER_MODULE))
> +#define ACPI_HOTPLUG_OST
> +#endif

Already covered in my general comments, but just in case:

This is restricted to a few of the possible cases _OST is intended for.
What happens when a kernel is configed with all of the above and PCI and
PCIe hotplug configs. _OST will only be evaluated in these cases,
shouldn't OS evaluate _OST in all cases once it tells firmware it
supports _OST in the case of Insertion/Ejection?

> +
> +/* _OST Source Event Code (OSPM Action) */
> +#define ACPI_OST_EC_OSPM_SHUTDOWN		0x100
> +#define ACPI_OST_EC_OSPM_EJECT			0x103
> +#define ACPI_OST_EC_OSPM_INSERTION		0x200
> +
> +/* _OST General Processing Status Code */
> +#define ACPI_OST_SC_SUCCESS			0x0
> +#define ACPI_OST_SC_NON_SPECIFIC_FAILURE	0x1
> +#define ACPI_OST_SC_UNRECOGNIZED_NOTIFY		0x2
> +
> +/* _OST OS Shutdown Processing (0x100) Status Code */
> +#define ACPI_OST_SC_OS_SHUTDOWN_DENIED		0x80
> +#define ACPI_OST_SC_OS_SHUTDOWN_IN_PROGRESS	0x81
> +#define ACPI_OST_SC_OS_SHUTDOWN_COMPLETED	0x82
> +#define ACPI_OST_SC_OS_SHUTDOWN_NOT_SUPPORTED	0x83
> +
> +/* _OST Ejection Request (0x3, 0x103) Status Code */
> +#define ACPI_OST_SC_EJECT_NOT_SUPPORTED		0x80
> +#define ACPI_OST_SC_DEVICE_IN_USE		0x81
> +#define ACPI_OST_SC_DEVICE_BUSY			0x82
> +#define ACPI_OST_SC_EJECT_DEPENDENCY_BUSY	0x83
> +#define ACPI_OST_SC_EJECT_IN_PROGRESS		0x84
> +
> +/* _OST Insertion Request (0x200) Status Code */
> +#define ACPI_OST_SC_INSERT_IN_PROGRESS		0x80
> +#define ACPI_OST_SC_DRIVER_LOAD_FAILURE		0x81
> +#define ACPI_OST_SC_INSERT_NOT_SUPPORTED	0x82
> +
>  extern void acpi_early_init(void);
>  
>  extern int acpi_nvs_register(__u64 start, __u64 size);