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+1. Introduction
+---------------
+**MvEeprom** driver creates MARVELL_EEPROM_PROTOCOL, which
++is used for managing eeprom.
+
+2. MvEeprom driver design
+-------------------------
+Every I2C device driver should implement EFI_DRIVER_BINDING_PROTOCOL and
+consume EFI_I2C_IO_PROTOCOL for transactions on I2C bus. MvEeprom driver
+additionally implements MARVELL_EEPROM_PROTOCOL.
+
+ 2.1 EFI_DRIVER_BINDING_PROTOCOL
+ -------------------------------
+ Driver Binding protocol is extensively covered in UEFI documentation, as
+ it is not specific to I2C stack. The only difference is that Supported()
+ function should check if EFI_I2C_IO_PROTOCOL provides valid EFI_GUID and
+ DeviceIndex values.
+ Excerpt from MvEepromSupported():
+
+ Status = gBS->OpenProtocol (
+ ControllerHandle,
+ &gEfiI2cIoProtocolGuid,
+ (VOID **) &TmpI2cIo,
+ gImageHandle,
+ ControllerHandle,
+ EFI_OPEN_PROTOCOL_BY_DRIVER
+ );
+ if (EFI_ERROR(Status)) {
+ return EFI_UNSUPPORTED;
+ }
+
+ /* get EEPROM devices' addresses from PCD */
+ EepromAddresses = PcdGetPtr (PcdEepromI2cAddresses);
+ if (EepromAddresses == 0) {
+ Status = EFI_UNSUPPORTED;
+ goto out;
+ }
+
+ Status = EFI_UNSUPPORTED;
+ for (i = 0; EepromAddresses[i] != '\0'; i++) {
+ /* I2C guid must fit and valid DeviceIndex must be provided */
+ if (CompareGuid(TmpI2cIo->DeviceGuid, &I2cGuid) &&
+ TmpI2cIo->DeviceIndex == EepromAddresses[i]) {
+ DEBUG((DEBUG_INFO, "A8kEepromSupported: attached to EEPROM device\n"));
+ Status = EFI_SUCCESS;
+ break;
+ }
+ }
+
+ 2.2 EFI_I2C_IO_PROTOCOL
+ -----------------------
+ This protocol is provided by generic I2C stack. Multiple drivers can use IO
+ protocol at once, as queueing is implemented.
+
+ QueueRequest is a routine that queues an I2C transaction to the I2C
+ controller for execution on the I2C bus.
+
+ 2.3 MARVELL_EEPROM_PROTOCOL
+ -----------------------
+ typedef struct _MARVELL_EEPROM_PROTOCOL MARVELL_EEPROM_PROTOCOL;
+
+ #define EEPROM_READ 0x1
+ #define EEPROM_WRITE 0x0
+ typedef
+ EFI_STATUS
+ (EFIAPI *EFI_EEPROM_TRANSFER) (
+ IN CONST MARVELL_EEPROM_PROTOCOL *This,
+ IN UINT16 Address,
+ IN UINT32 Length,
+ IN UINT8 *Buffer,
+ IN UINT8 Operation
+ );
+
+ struct _MARVELL_EEPROM_PROTOCOL {
+ EFI_EEPROM_TRANSFER Transfer;
+ UINT8 Identifier;
+ };
+
+3. Adding new I2C slave device drivers
+--------------------------------------
+In order to support I2C slave device other than EEPROM, new driver should
+be created. Required steps follow.
+
+ 1. Create driver directory (Platform/Marvell/Drivers/I2c/Devices/...).
+ 2. Create stubs of .inf and .c files (MvEeprom files are a reference),
+ include .inf file in platform .dsc and .fdf files.
+ 3. Implement EFI_DRIVER_BINDING_PROTOCOL - Start(), Stop(), Supported()
+ functions' implementation is a must. EFI_DRIVER_BINDING_PROTOCOL
+ should be installed at driver's entry point.
+ 4. Add I2C address of device to PcdI2cSlaveAddresses in .dsc file.
+ 5. Test available EFI_I2C_IO_PROTOCOLs in Supported() - find instance
+ with valid GUID and DeviceIndex (I2C slave address).
+ 6. Open EFI_I2C_IO_PROTOCOL for usage in Start(). After that, QueueRequest
+ function should be available.
+ 7. Implement core functionality of driver (using QueueRequest to access I2C).
+ 8. (not mandatory) Produce/consume additional protocols.