audk/MdePkg/Include/Protocol/SmmPeriodicTimerDispatch.h

/** @file
  This file declares EFI Smm Periodic Timer Smi Child Protocol

  Copyright (c) 2006, Intel Corporation                                                         
  All rights reserved. This program and the accompanying materials                          
  are licensed and made available under the terms and conditions of the BSD License         
  which accompanies this distribution.  The full text of the license may be found at        
  http://opensource.org/licenses/bsd-license.php                                            

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             

  Module Name:  SmmPeriodicTimerDispatch.h

  @par Revision Reference:
  This Protocol is defined in Framework of EFI SMM Core Interface Spec
  Version 0.9.

**/

#ifndef _EFI_SMM_PERIODIC_TIMER_DISPATCH_H_
#define _EFI_SMM_PERIODIC_TIMER_DISPATCH_H_

//
// Global ID for the Periodic Timer SMI Protocol
//
#define EFI_SMM_PERIODIC_TIMER_DISPATCH_PROTOCOL_GUID \
  { \
    0x9cca03fc, 0x4c9e, 0x4a19, {0x9b, 0x6, 0xed, 0x7b, 0x47, 0x9b, 0xde, 0x55 } \
  }

typedef struct _EFI_SMM_PERIODIC_TIMER_DISPATCH_PROTOCOL  EFI_SMM_PERIODIC_TIMER_DISPATCH_PROTOCOL;

//
// Related Definitions
//
//
// Period is the minimum period of time in 100 nanosecond units that child gets called.
// The child will be called back after a time greater than the time Period.
//
// SmiTickInterval is the period of time interval between SMIs.  Children of this interface
// should use this field when registering for periodic timer intervals when a finer
// granularity periodic SMI is desired.  Valid values for this field are those returned
// by GetNextInterval.  A value of 0 indicates the parent is allowed to use any SMI
// interval period to satisfy the requested period.
//    Example: A chipset supports periodic SMIs on every 64ms or 2 seconds.
//      A child wishes schedule a period SMI to fire on a period of 3 seconds, there
//      are several ways to approach the problem:
//      1. The child may accept a 4 second periodic rate, in which case it registers with
//           Period = 40000
//           SmiTickInterval = 20000
//         The resulting SMI will occur every 2 seconds with the child called back on
//         every 2nd SMI.
//         NOTE: the same result would occur if the child set SmiTickInterval = 0.
//      2. The child may choose the finer granularity SMI (64ms):
//           Period = 30000
//           SmiTickInterval = 640
//         The resulting SMI will occur every 64ms with the child called back on
//         every 47th SMI.
//         NOTE: the child driver should be aware that this will result in more
//           SMIs occuring during system runtime which can negatively impact system
//           performance.
//
// ElapsedTime is the actual time in 100 nanosecond units elapsed since last called, a
// value of 0 indicates an unknown amount of time.
//
typedef struct {
  UINT64  Period;
  UINT64  SmiTickInterval;
  UINT64  ElapsedTime;
} EFI_SMM_PERIODIC_TIMER_DISPATCH_CONTEXT;

//
// Member functions
//
/**
  Dispatch function for a Periodic Timer SMI handler.

  @param  DispatchHandle        Handle of this dispatch function.
  @param  DispatchContext       Pointer to the dispatch function's context.
                                The DispatchContext fields are filled in
                                by the dispatching driver prior to
                                invoking this dispatch function.

  Nothing

**/
typedef
VOID
(EFIAPI *EFI_SMM_PERIODIC_TIMER_DISPATCH) (
  IN  EFI_HANDLE                                DispatchHandle,
  IN  EFI_SMM_PERIODIC_TIMER_DISPATCH_CONTEXT   *DispatchContext
  );

/**
  Returns the next SMI tick period supported by the chipset.  The order
  returned is from longest to shortest interval period.

  @param  This                  Protocol instance pointer.
  @param  SmiTickInterval       Pointer to pointer of next shorter SMI interval
                                period supported by the child. This parameter works as a get-first,
                                get-next field.The first time this function is called, *SmiTickInterval
                                should be set to NULL to get the longest SMI interval.The returned
                                *SmiTickInterval should be passed in on subsequent calls to get the
                                next shorter interval period until *SmiTickInterval = NULL.

  @retval EFI_SUCCESS           The service returned successfully.

**/
typedef
EFI_STATUS
(EFIAPI *EFI_SMM_PERIODIC_TIMER_INTERVAL) (
  IN EFI_SMM_PERIODIC_TIMER_DISPATCH_PROTOCOL           *This,
  IN OUT UINT64                                         **SmiTickInterval
  );

/**
  Register a child SMI source dispatch function with a parent SMM driver

  @param  This                  Protocol instance pointer.
  @param  DispatchFunction      Pointer to dispatch function to be invoked for
                                this SMI source
  @param  DispatchContext       Pointer to the dispatch function's context.
                                The caller fills this context in before calling
                                the register function to indicate to the register
                                function the period at which the dispatch function
                                should be invoked.
  @param  DispatchHandle        Handle of dispatch function, for when interfacing
                                with the parent Sx state SMM driver.

  @retval EFI_SUCCESS           The dispatch function has been successfully
                                registered and the SMI source has been enabled.
  @retval EFI_DEVICE_ERROR      The driver was unable to enable the SMI source.
  @retval EFI_OUT_OF_RESOURCES  Not enough memory (system or SMM) to manage this
                                child.
  @retval EFI_INVALID_PARAMETER DispatchContext is invalid. The period input value
                                is not within valid range.

**/
typedef
EFI_STATUS
(EFIAPI *EFI_SMM_PERIODIC_TIMER_REGISTER) (
  IN EFI_SMM_PERIODIC_TIMER_DISPATCH_PROTOCOL           *This,
  IN  EFI_SMM_PERIODIC_TIMER_DISPATCH                   DispatchFunction,
  IN  EFI_SMM_PERIODIC_TIMER_DISPATCH_CONTEXT           *DispatchContext,
  OUT EFI_HANDLE                                        *DispatchHandle
  );

/**
  Unregister a child SMI source dispatch function with a parent SMM driver

  @param  This                  Protocol instance pointer.
  @param  DispatchHandle        Handle of dispatch function to deregister.

  @retval EFI_SUCCESS           The dispatch function has been successfully
                                unregistered and the SMI source has been disabled
                                if there are no other registered child dispatch
                                functions for this SMI source.
  @retval EFI_INVALID_PARAMETER Handle is invalid.

**/
typedef
EFI_STATUS
(EFIAPI *EFI_SMM_PERIODIC_TIMER_UNREGISTER) (
  IN EFI_SMM_PERIODIC_TIMER_DISPATCH_PROTOCOL           *This,
  IN  EFI_HANDLE                                        DispatchHandle
  );

//
// Interface structure for the SMM Periodic Timer Dispatch Protocol
//
/**
  @par Protocol Description:
  Provides the parent dispatch service for the periodical timer SMI source generator.

  @param Register
  Installs a child service to be dispatched by this protocol.

  @param UnRegister
  Removes a child service dispatched by this protocol.

  @param GetNextShorterInterval
  Returns the next SMI tick period that is supported by the chipset. 

**/
struct _EFI_SMM_PERIODIC_TIMER_DISPATCH_PROTOCOL {
  EFI_SMM_PERIODIC_TIMER_REGISTER   Register;
  EFI_SMM_PERIODIC_TIMER_UNREGISTER UnRegister;
  EFI_SMM_PERIODIC_TIMER_INTERVAL   GetNextShorterInterval;
};

extern EFI_GUID gEfiSmmPeriodicTimerDispatchProtocolGuid;

#endif