I2cBus.c File Reference

#include "I2cDxe.h"

Go to the source code of this file.

Functions
EFI_STATUS EFIAPI	I2cBusComponentNameGetDriverName (IN EFI_COMPONENT_NAME2_PROTOCOL *This, IN CHAR8 *Language, OUT CHAR16 **DriverName)
EFI_STATUS EFIAPI	I2cBusComponentNameGetControllerName (IN EFI_COMPONENT_NAME2_PROTOCOL *This, IN EFI_HANDLE ControllerHandle, IN EFI_HANDLE ChildHandle OPTIONAL, IN CHAR8 *Language, OUT CHAR16 **ControllerName)
EFI_STATUS	CheckRemainingDevicePath (IN EFI_DRIVER_BINDING_PROTOCOL *This, IN EFI_HANDLE Controller, IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath, IN BOOLEAN RemainingHasControllerNode, IN UINT32 RemainingControllerNumber)
EFI_STATUS EFIAPI	I2cBusDriverSupported (IN EFI_DRIVER_BINDING_PROTOCOL *This, IN EFI_HANDLE Controller, IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath)
EFI_STATUS EFIAPI	I2cBusDriverStart (IN EFI_DRIVER_BINDING_PROTOCOL *This, IN EFI_HANDLE Controller, IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath)
EFI_STATUS EFIAPI	I2cBusDriverStop (IN EFI_DRIVER_BINDING_PROTOCOL *This, IN EFI_HANDLE Controller, IN UINTN NumberOfChildren, IN EFI_HANDLE *ChildHandleBuffer)
EFI_STATUS	RegisterI2cDevice (IN I2C_BUS_CONTEXT *I2cBusContext, IN EFI_HANDLE Controller, IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath)
EFI_STATUS EFIAPI	I2cBusQueueRequest (IN CONST EFI_I2C_IO_PROTOCOL *This, IN UINTN SlaveAddressIndex, IN EFI_EVENT Event OPTIONAL, IN EFI_I2C_REQUEST_PACKET *RequestPacket, OUT EFI_STATUS *I2cStatus OPTIONAL)
VOID	ReleaseI2cDeviceContext (IN I2C_DEVICE_CONTEXT *I2cDeviceContext)
EFI_STATUS	UnRegisterI2cDevice (IN EFI_DRIVER_BINDING_PROTOCOL *This, IN EFI_HANDLE Controller, IN EFI_HANDLE Handle)
EFI_STATUS	I2cBusDevicePathAppend (IN I2C_DEVICE_CONTEXT *I2cDeviceContext, IN BOOLEAN BuildControllerNode)
EFI_STATUS EFIAPI	InitializeI2cBus (IN EFI_HANDLE ImageHandle, IN EFI_SYSTEM_TABLE *SystemTable)
EFI_STATUS EFIAPI	I2cBusUnload (IN EFI_HANDLE ImageHandle)

Variables
EFI_DRIVER_BINDING_PROTOCOL	gI2cBusDriverBinding
I2C_DEVICE_CONTEXT	gI2cDeviceContextTemplate
CONTROLLER_DEVICE_PATH	gControllerDevicePathTemplate
VENDOR_DEVICE_PATH	gVendorDevicePathTemplate
GLOBAL_REMOVE_IF_UNREFERENCED EFI_UNICODE_STRING_TABLE	mI2cBusDriverNameTable []
GLOBAL_REMOVE_IF_UNREFERENCED EFI_COMPONENT_NAME_PROTOCOL	gI2cBusComponentName
GLOBAL_REMOVE_IF_UNREFERENCED EFI_COMPONENT_NAME2_PROTOCOL	gI2cBusComponentName2

Detailed Description

This file implements I2C IO Protocol which enables the user to manipulate a single I2C device independent of the host controller and I2C design.

Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file I2cBus.c.

Function Documentation

CheckRemainingDevicePath()

EFI_STATUS CheckRemainingDevicePath	(	IN EFI_DRIVER_BINDING_PROTOCOL *	This,
		IN EFI_HANDLE	Controller,
		IN EFI_DEVICE_PATH_PROTOCOL *	RemainingDevicePath,
		IN BOOLEAN	RemainingHasControllerNode,
		IN UINT32	RemainingControllerNumber
	)

Check if the child of I2C controller has been created.

Parameters

[in]	This	A pointer to the EFI_DRIVER_BINDING_PROTOCOL instance.
[in]	Controller	I2C controller handle.
[in]	RemainingDevicePath	A pointer to the remaining portion of a device path.
[in]	RemainingHasControllerNode	Indicate if RemainingDevicePath contains CONTROLLER_DEVICE_PATH.
[in]	RemainingControllerNumber	Controller number in CONTROLLER_DEVICE_PATH.

Return values

EFI_SUCCESS	The child of I2C controller is not created.
Others	The child of I2C controller has been created or other errors happen.

Definition at line 250 of file I2cBus.c.

I2cBusComponentNameGetControllerName()

EFI_STATUS EFIAPI I2cBusComponentNameGetControllerName	(	IN EFI_COMPONENT_NAME2_PROTOCOL *	This,
		IN EFI_HANDLE	ControllerHandle,
		IN EFI_HANDLE ChildHandle	OPTIONAL,
		IN CHAR8 *	Language,
		OUT CHAR16 **	ControllerName
	)

Retrieves a Unicode string that is the user readable name of the controller that is being managed by a driver.

This function retrieves the user readable name of the controller specified by ControllerHandle and ChildHandle in the form of a Unicode string. If the driver specified by This has a user readable name in the language specified by Language, then a pointer to the controller name is returned in ControllerName, and EFI_SUCCESS is returned. If the driver specified by This is not currently managing the controller specified by ControllerHandle and ChildHandle, then EFI_UNSUPPORTED is returned. If the driver specified by This does not support the language specified by Language, then EFI_UNSUPPORTED is returned.

Parameters

This[in]	A pointer to the EFI_COMPONENT_NAME2_PROTOCOL or EFI_COMPONENT_NAME_PROTOCOL instance.
ControllerHandle[in]	The handle of a controller that the driver specified by This is managing. This handle specifies the controller whose name is to be returned.
ChildHandle[in]	The handle of the child controller to retrieve the name of. This is an optional parameter that may be NULL. It will be NULL for device drivers. It will also be NULL for a bus drivers that wish to retrieve the name of the bus controller. It will not be NULL for a bus driver that wishes to retrieve the name of a child controller.
Language[in]	A pointer to a Null-terminated ASCII string array indicating the language. This is the language of the driver name that the caller is requesting, and it must match one of the languages specified in SupportedLanguages. The number of languages supported by a driver is up to the driver writer. Language is specified in RFC 4646 or ISO 639-2 language code format.
ControllerName[out]	A pointer to the Unicode string to return. This Unicode string is the name of the controller specified by ControllerHandle and ChildHandle in the language specified by Language from the point of view of the driver specified by This.

Return values

EFI_SUCCESS	The Unicode string for the user readable name in the language specified by Language for the driver specified by This was returned in DriverName.
EFI_INVALID_PARAMETER	ControllerHandle is NULL.
EFI_INVALID_PARAMETER	ChildHandle is not NULL and it is not a valid EFI_HANDLE.
EFI_INVALID_PARAMETER	Language is NULL.
EFI_INVALID_PARAMETER	ControllerName is NULL.
EFI_UNSUPPORTED	The driver specified by This is not currently managing the controller specified by ControllerHandle and ChildHandle.
EFI_UNSUPPORTED	The driver specified by This does not support the language specified by Language.

Definition at line 225 of file I2cBus.c.

I2cBusComponentNameGetDriverName()

EFI_STATUS EFIAPI I2cBusComponentNameGetDriverName	(	IN EFI_COMPONENT_NAME2_PROTOCOL *	This,
		IN CHAR8 *	Language,
		OUT CHAR16 **	DriverName
	)

Retrieves a Unicode string that is the user readable name of the driver.

This function retrieves the user readable name of a driver in the form of a Unicode string. If the driver specified by This has a user readable name in the language specified by Language, then a pointer to the driver name is returned in DriverName, and EFI_SUCCESS is returned. If the driver specified by This does not support the language specified by Language, then EFI_UNSUPPORTED is returned.

Parameters

This[in]	A pointer to the EFI_COMPONENT_NAME2_PROTOCOL or EFI_COMPONENT_NAME_PROTOCOL instance.
Language[in]	A pointer to a Null-terminated ASCII string array indicating the language. This is the language of the driver name that the caller is requesting, and it must match one of the languages specified in SupportedLanguages. The number of languages supported by a driver is up to the driver writer. Language is specified in RFC 4646 or ISO 639-2 language code format.
DriverName[out]	A pointer to the Unicode string to return. This Unicode string is the name of the driver specified by This in the language specified by Language.

Return values

EFI_SUCCESS	The Unicode string for the Driver specified by This and the language specified by Language was returned in DriverName.
EFI_INVALID_PARAMETER	Language is NULL.
EFI_INVALID_PARAMETER	DriverName is NULL.
EFI_UNSUPPORTED	The driver specified by This does not support the language specified by Language.

Definition at line 140 of file I2cBus.c.

I2cBusDevicePathAppend()

EFI_STATUS I2cBusDevicePathAppend	(	IN I2C_DEVICE_CONTEXT *	I2cDeviceContext,
		IN BOOLEAN	BuildControllerNode
	)

Create a path for the I2C device

Append the I2C slave path to the I2C master controller path.

Parameters

[in]	I2cDeviceContext	Address of an I2C_DEVICE_CONTEXT structure.
[in]	BuildControllerNode	Flag to build controller node in device path.

Return values

EFI_SUCCESS

The I2C device path is built successfully.

Returns

Others It is failed to built device path.

Definition at line 1317 of file I2cBus.c.

I2cBusDriverStart()

EFI_STATUS EFIAPI I2cBusDriverStart	(	IN EFI_DRIVER_BINDING_PROTOCOL *	This,
		IN EFI_HANDLE	Controller,
		IN EFI_DEVICE_PATH_PROTOCOL *	RemainingDevicePath
	)

Starts a device controller or a bus controller.

The Start() function is designed to be invoked from the EFI boot service ConnectController(). As a result, much of the error checking on the parameters to Start() has been moved into this common boot service. It is legal to call Start() from other locations, but the following calling restrictions must be followed or the system behavior will not be deterministic.

1. ControllerHandle must be a valid EFI_HANDLE.
2. If RemainingDevicePath is not NULL, then it must be a pointer to a naturally aligned EFI_DEVICE_PATH_PROTOCOL.
3. Prior to calling Start(), the Supported() function for the driver specified by This must have been called with the same calling parameters, and Supported() must have returned EFI_SUCCESS.

Parameters

[in]	This	A pointer to the EFI_DRIVER_BINDING_PROTOCOL instance.
[in]	ControllerHandle	The handle of the controller to start. This handle must support a protocol interface that supplies an I/O abstraction to the driver.
[in]	RemainingDevicePath	A pointer to the remaining portion of a device path. This parameter is ignored by device drivers, and is optional for bus drivers. For a bus driver, if this parameter is NULL, then handles for all the children of Controller are created by this driver. If this parameter is not NULL and the first Device Path Node is not the End of Device Path Node, then only the handle for the child device specified by the first Device Path Node of RemainingDevicePath is created by this driver. If the first Device Path Node of RemainingDevicePath is the End of Device Path Node, no child handle is created by this driver.

Return values

EFI_SUCCESS	The device was started.
EFI_DEVICE_ERROR	The device could not be started due to a device error.Currently not implemented.
EFI_OUT_OF_RESOURCES	The request could not be completed due to a lack of resources.
Others	The driver failed to start the device.

Definition at line 557 of file I2cBus.c.

I2cBusDriverStop()

EFI_STATUS EFIAPI I2cBusDriverStop	(	IN EFI_DRIVER_BINDING_PROTOCOL *	This,
		IN EFI_HANDLE	Controller,
		IN UINTN	NumberOfChildren,
		IN EFI_HANDLE *	ChildHandleBuffer
	)

Stops a device controller or a bus controller.

The Stop() function is designed to be invoked from the EFI boot service DisconnectController(). As a result, much of the error checking on the parameters to Stop() has been moved into this common boot service. It is legal to call Stop() from other locations, but the following calling restrictions must be followed or the system behavior will not be deterministic.

1. ControllerHandle must be a valid EFI_HANDLE that was used on a previous call to this same driver's Start() function.
2. The first NumberOfChildren handles of ChildHandleBuffer must all be a valid EFI_HANDLE. In addition, all of these handles must have been created in this driver's Start() function, and the Start() function must have called OpenProtocol() on ControllerHandle with an Attribute of EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER.

Parameters

[in]	This	A pointer to the EFI_DRIVER_BINDING_PROTOCOL instance.
[in]	ControllerHandle	A handle to the device being stopped. The handle must support a bus specific I/O protocol for the driver to use to stop the device.
[in]	NumberOfChildren	The number of child device handles in ChildHandleBuffer.
[in]	ChildHandleBuffer	An array of child handles to be freed. May be NULL if NumberOfChildren is 0.

Return values

EFI_SUCCESS	The device was stopped.
EFI_DEVICE_ERROR	The device could not be stopped due to a device error.

Definition at line 777 of file I2cBus.c.

I2cBusDriverSupported()

EFI_STATUS EFIAPI I2cBusDriverSupported	(	IN EFI_DRIVER_BINDING_PROTOCOL *	This,
		IN EFI_HANDLE	Controller,
		IN EFI_DEVICE_PATH_PROTOCOL *	RemainingDevicePath
	)

Tests to see if this driver supports a given controller. If a child device is provided, it further tests to see if this driver supports creating a handle for the specified child device.

This function checks to see if the driver specified by This supports the device specified by ControllerHandle. Drivers will typically use the device path attached to ControllerHandle and/or the services from the bus I/O abstraction attached to ControllerHandle to determine if the driver supports ControllerHandle. This function may be called many times during platform initialization. In order to reduce boot times, the tests performed by this function must be very small, and take as little time as possible to execute. This function must not change the state of any hardware devices, and this function must be aware that the device specified by ControllerHandle may already be managed by the same driver or a different driver. This function must match its calls to AllocatePages() with FreePages(), AllocatePool() with FreePool(), and OpenProtocol() with CloseProtocol(). Since ControllerHandle may have been previously started by the same driver, if a protocol is already in the opened state, then it must not be closed with CloseProtocol(). This is required to guarantee the state of ControllerHandle is not modified by this function.

Parameters

[in]	This	A pointer to the EFI_DRIVER_BINDING_PROTOCOL instance.
[in]	ControllerHandle	The handle of the controller to test. This handle must support a protocol interface that supplies an I/O abstraction to the driver.
[in]	RemainingDevicePath	A pointer to the remaining portion of a device path. This parameter is ignored by device drivers, and is optional for bus drivers. For bus drivers, if this parameter is not NULL, then the bus driver must determine if the bus controller specified by ControllerHandle and the child controller specified by RemainingDevicePath are both supported by this bus driver.

Return values

EFI_SUCCESS	The device specified by ControllerHandle and RemainingDevicePath is supported by the driver specified by This.
EFI_ALREADY_STARTED	The device specified by ControllerHandle and RemainingDevicePath is already being managed by the driver specified by This.
EFI_ACCESS_DENIED	The device specified by ControllerHandle and RemainingDevicePath is already being managed by a different driver or an application that requires exclusive access. Currently not implemented.
EFI_UNSUPPORTED	The device specified by ControllerHandle and RemainingDevicePath is not supported by the driver specified by This.

Definition at line 385 of file I2cBus.c.

I2cBusQueueRequest()

EFI_STATUS EFIAPI I2cBusQueueRequest	(	IN CONST EFI_I2C_IO_PROTOCOL *	This,
		IN UINTN	SlaveAddressIndex,
		IN EFI_EVENT Event	OPTIONAL,
		IN EFI_I2C_REQUEST_PACKET *	RequestPacket,
		OUT EFI_STATUS *I2cStatus	OPTIONAL
	)

Queue an I2C transaction for execution on the I2C device.

This routine must be called at or below TPL_NOTIFY. For synchronous requests this routine must be called at or below TPL_CALLBACK.

This routine queues an I2C transaction to the I2C controller for execution on the I2C bus.

When Event is NULL, QueueRequest() operates synchronously and returns the I2C completion status as its return value.

When Event is not NULL, QueueRequest() synchronously returns EFI_SUCCESS indicating that the asynchronous I2C transaction was queued. The values above are returned in the buffer pointed to by I2cStatus upon the completion of the I2C transaction when I2cStatus is not NULL.

The upper layer driver writer provides the following to the platform vendor:

1. Vendor specific GUID for the I2C part
2. Guidance on proper construction of the slave address array when the I2C device uses more than one slave address. The I2C bus protocol uses the SlaveAddressIndex to perform relative to physical address translation to access the blocks of hardware within the I2C device.

Parameters

[in]	This	Pointer to an EFI_I2C_IO_PROTOCOL structure.
[in]	SlaveAddressIndex	Index value into an array of slave addresses for the I2C device. The values in the array are specified by the board designer, with the third party I2C device driver writer providing the slave address order.

For devices that have a single slave address, this value must be zero. If the I2C device uses more than one slave address then the third party (upper level) I2C driver writer needs to specify the order of entries in the slave address array.

Third Party I2C Drivers" section in I2cMaster.h.

Parameters

[in]	Event	Event to signal for asynchronous transactions, NULL for synchronous transactions
[in]	RequestPacket	Pointer to an EFI_I2C_REQUEST_PACKET structure describing the I2C transaction
[out]	I2cStatus	Optional buffer to receive the I2C transaction completion status

Return values

EFI_SUCCESS	The asynchronous transaction was successfully queued when Event is not NULL.
EFI_SUCCESS	The transaction completed successfully when Event is NULL.
EFI_BAD_BUFFER_SIZE	The RequestPacket->LengthInBytes value is too large.
EFI_DEVICE_ERROR	There was an I2C error (NACK) during the transaction.
EFI_INVALID_PARAMETER	RequestPacket is NULL
EFI_NO_MAPPING	The EFI_I2C_HOST_PROTOCOL could not set the bus configuration required to access this I2C device.
EFI_NO_RESPONSE	The I2C device is not responding to the slave address selected by SlaveAddressIndex. EFI_DEVICE_ERROR will be returned if the controller cannot distinguish when the NACK occurred.
EFI_OUT_OF_RESOURCES	Insufficient memory for I2C transaction
EFI_UNSUPPORTED	The controller does not support the requested transaction.

Definition at line 1141 of file I2cBus.c.

I2cBusUnload()

EFI_STATUS EFIAPI I2cBusUnload

(

IN EFI_HANDLE

ImageHandle

)

This is the unload handle for I2C bus module.

Disconnect the driver specified by ImageHandle from all the devices in the handle database. Uninstall all the protocols installed in the driver entry point.

Parameters

[in]

ImageHandle

The drivers' driver image.

Return values

EFI_SUCCESS	The image is unloaded.
Others	Failed to unload the image.

Definition at line 1409 of file I2cBus.c.

InitializeI2cBus()

EFI_STATUS EFIAPI InitializeI2cBus	(	IN EFI_HANDLE	ImageHandle,
		IN EFI_SYSTEM_TABLE *	SystemTable
	)

The user entry point for the I2C bus module. The user code starts with this function.

Parameters

[in]	ImageHandle	The firmware allocated handle for the EFI image.
[in]	SystemTable	A pointer to the EFI System Table.

Return values

EFI_SUCCESS	The entry point is executed successfully.
other	Some error occurs when executing this entry point.

Definition at line 1372 of file I2cBus.c.

RegisterI2cDevice()

EFI_STATUS RegisterI2cDevice	(	IN I2C_BUS_CONTEXT *	I2cBusContext,
		IN EFI_HANDLE	Controller,
		IN EFI_DEVICE_PATH_PROTOCOL *	RemainingDevicePath
	)

Enumerate the I2C bus

This routine walks the platform specific data describing the I2C bus to create the I2C devices where driver GUIDs were specified.

Parameters

[in]	I2cBusContext	Address of an I2C_BUS_CONTEXT structure
[in]	Controller	Handle to the controller
[in]	RemainingDevicePath	A pointer to the remaining portion of a device path.

Return values

EFI_SUCCESS

The bus is successfully configured

Definition at line 866 of file I2cBus.c.

ReleaseI2cDeviceContext()

VOID ReleaseI2cDeviceContext

(

IN I2C_DEVICE_CONTEXT *

I2cDeviceContext

)

Release all the resources allocated for the I2C device.

This function releases all the resources allocated for the I2C device.

Parameters

I2cDeviceContext

The I2C child device involved for the operation.

Definition at line 1198 of file I2cBus.c.

UnRegisterI2cDevice()

EFI_STATUS UnRegisterI2cDevice	(	IN EFI_DRIVER_BINDING_PROTOCOL *	This,
		IN EFI_HANDLE	Controller,
		IN EFI_HANDLE	Handle
	)

Unregister an I2C device.

This function removes the protocols installed on the controller handle and frees the resources allocated for the I2C device.

Parameters

This	The pointer to EFI_DRIVER_BINDING_PROTOCOL instance.
Controller	The controller handle of the I2C device.
Handle	The child handle.

Return values

EFI_SUCCESS

The I2C device is successfully unregistered.

Returns

Others Some error occurs when unregistering the I2C device.

Definition at line 1228 of file I2cBus.c.

Variable Documentation

gControllerDevicePathTemplate

CONTROLLER_DEVICE_PATH gControllerDevicePathTemplate

Initial value:

= {
  {
    HARDWARE_DEVICE_PATH,
    HW_CONTROLLER_DP,
    {
      (UINT8)(sizeof (CONTROLLER_DEVICE_PATH)),
      (UINT8)((sizeof (CONTROLLER_DEVICE_PATH)) >> 8)
    }
  },
  0
}

Definition at line 45 of file I2cBus.c.

gI2cBusComponentName

GLOBAL_REMOVE_IF_UNREFERENCED EFI_COMPONENT_NAME_PROTOCOL gI2cBusComponentName

Initial value:

= {
  (EFI_COMPONENT_NAME_GET_DRIVER_NAME)I2cBusComponentNameGetDriverName,
  (EFI_COMPONENT_NAME_GET_CONTROLLER_NAME)I2cBusComponentNameGetControllerName,
  "eng"
}

Definition at line 84 of file I2cBus.c.

gI2cBusComponentName2

GLOBAL_REMOVE_IF_UNREFERENCED EFI_COMPONENT_NAME2_PROTOCOL gI2cBusComponentName2

Initial value:

= {
  I2cBusComponentNameGetDriverName,
  I2cBusComponentNameGetControllerName,
  "en"
}

Definition at line 93 of file I2cBus.c.

gI2cBusDriverBinding

EFI_DRIVER_BINDING_PROTOCOL gI2cBusDriverBinding

Initial value:

= {
  I2cBusDriverSupported,
  I2cBusDriverStart,
  I2cBusDriverStop,
  0x10,
  NULL,
  NULL
}

Definition at line 15 of file I2cBus.c.

gI2cDeviceContextTemplate

I2C_DEVICE_CONTEXT gI2cDeviceContextTemplate

Initial value:

= {
  I2C_DEVICE_SIGNATURE,
  NULL,
  {                     
    I2cBusQueueRequest, 
    NULL,               
    0,                  
    0,                  
    NULL                
  },
  NULL,                 
  NULL,                 
  NULL,                 
}

Definition at line 27 of file I2cBus.c.

gVendorDevicePathTemplate

VENDOR_DEVICE_PATH gVendorDevicePathTemplate

Initial value:

= {
  {
    HARDWARE_DEVICE_PATH,
    HW_VENDOR_DP,
    {
      (UINT8)(sizeof (VENDOR_DEVICE_PATH)),
      (UINT8)((sizeof (VENDOR_DEVICE_PATH)) >> 8)
    }
  },
  { 0x0, 0x0, 0x0, { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 }
  }
}

Definition at line 60 of file I2cBus.c.

mI2cBusDriverNameTable

GLOBAL_REMOVE_IF_UNREFERENCED EFI_UNICODE_STRING_TABLE mI2cBusDriverNameTable[]

Initial value:

= {
  { "eng;en", (CHAR16 *)L"I2C Bus Driver" },
  { NULL,     NULL                        }
}

Definition at line 76 of file I2cBus.c.