This file defines the SPI I/O Protocol.
Copyright (c) 2017, Intel Corporation. All rights reserved.
Copyright (C) 2024 Advanced Micro Devices, Inc. All rights reserved. SPDX-License-Identifier: BSD-2-Clause-Patent
- Revision Reference:
- This Protocol was introduced in UEFI PI Specification 1.8 A.
Definition in file SpiIo.h.
Initiate a SPI transaction between the host and a SPI peripheral.
This routine must be called at or below TPL_NOTIFY. This routine works with the SPI bus layer to pass the SPI transaction to the SPI controller for execution on the SPI bus. There are four types of supported transactions supported by this routine: Full Duplex: WriteBuffer and ReadBuffer are the same size. Write Only: WriteBuffer contains data for SPI peripheral, ReadBytes = 0 Read Only: ReadBuffer to receive data from SPI peripheral, WriteBytes = 0 Write Then Read: WriteBuffer contains control data to write to SPI peripheral before data is placed into the ReadBuffer. Both WriteBytes and ReadBytes must be non-zero.
- Parameters
-
| [in] | This | Pointer to an EFI_SPI_IO_PROTOCOL structure. |
| [in] | TransactionType | Type of SPI transaction. |
| [in] | DebugTransaction | Set TRUE only when debugging is desired. Debugging may be turned on for a single SPI transaction. Only this transaction will display debugging messages. All other transactions with this value set to FALSE will not display any debugging messages. |
| [in] | ClockHz | Specify the ClockHz value as zero (0) to use the maximum clock frequency supported by the SPI controller and part. Specify a non-zero value only when a specific SPI transaction requires a reduced clock rate. |
| [in] | BusWidth | Width of the SPI bus in bits: 1, 2, 4 |
| [in] | FrameSize | Frame size in bits, range: 1 - 32 |
| [in] | WriteBytes | The length of the WriteBuffer in bytes. Specify zero for read-only operations. |
| [in] | WriteBuffer | The buffer containing data to be sent from the host to the SPI chip. Specify NULL for read only operations. Frame sizes 1-8 bits: UINT8 (one byte) per frame Frame sizes 7-16 bits: UINT16 (two bytes) per frame Frame sizes 17-32 bits: UINT32 (four bytes) per frame The transmit frame is in the least significant N bits. |
| [in] | ReadBytes | The length of the ReadBuffer in bytes. Specify zero for write-only operations. |
| [out] | ReadBuffer | The buffer to receeive data from the SPI chip during the transaction. Specify NULL for write only operations. Frame sizes 1-8 bits: UINT8 (one byte) per frame Frame sizes 7-16 bits: UINT16 (two bytes) per frame Frame sizes 17-32 bits: UINT32 (four bytes) per frame The received frame is in the least significant N bits. |
- Return values
-
| EFI_SUCCESS | The SPI transaction completed successfully |
| EFI_BAD_BUFFER_SIZE | The writeBytes value was invalid |
| EFI_BAD_BUFFER_SIZE | The ReadBytes value was invalid |
| EFI_INVALID_PARAMETER | TransactionType is not valid, or BusWidth not supported by SPI peripheral or SPI host controller, or WriteBytes non-zero and WriteBuffer is NULL, or ReadBytes non-zero and ReadBuffer is NULL, or ReadBuffer != WriteBuffer for full-duplex type, or WriteBuffer was NULL, or TPL is too high |
| EFI_OUT_OF_RESOURCES | Insufficient memory for SPI transaction |
| EFI_UNSUPPORTED | The FrameSize is not supported by the SPI bus layer or the SPI host controller |
| EFI_UNSUPPORTED | The SPI controller was not able to support |
Definition at line 128 of file SpiIo.h.
1.9.6