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- /** @file
- UART Serial Port library functions
- Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- **/
- #include <Base.h>
- #include <Library/IoLib.h>
- #include <Library/SerialPortLib.h>
- // ---------------------------------------------
- // UART Register Offsets
- // ---------------------------------------------
- #define BAUD_LOW_OFFSET 0x00
- #define BAUD_HIGH_OFFSET 0x01
- #define IER_OFFSET 0x01
- #define LCR_SHADOW_OFFSET 0x01
- #define FCR_SHADOW_OFFSET 0x02
- #define IR_CONTROL_OFFSET 0x02
- #define FCR_OFFSET 0x02
- #define EIR_OFFSET 0x02
- #define BSR_OFFSET 0x03
- #define LCR_OFFSET 0x03
- #define MCR_OFFSET 0x04
- #define LSR_OFFSET 0x05
- #define MSR_OFFSET 0x06
- // ---------------------------------------------
- // UART Register Bit Defines
- // ---------------------------------------------
- #define LSR_TXRDY 0x20
- #define LSR_RXDA 0x01
- #define DLAB 0x01
- #define MCR_DTRC 0x01
- #define MCR_RTS 0x02
- #define MSR_CTS 0x10
- #define MSR_DSR 0x20
- #define MSR_RI 0x40
- #define MSR_DCD 0x80
- // ---------------------------------------------
- // UART Settings
- // ---------------------------------------------
- UINT16 gUartBase = 0x3F8;
- UINTN gBps = 115200;
- UINT8 gData = 8;
- UINT8 gStop = 1;
- UINT8 gParity = 0;
- UINT8 gBreakSet = 0;
- /**
- Initialize the serial device hardware.
- If no initialization is required, then return RETURN_SUCCESS.
- If the serial device was successfully initialized, then return RETURN_SUCCESS.
- If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.
- @retval RETURN_SUCCESS The serial device was initialized.
- @retval RETURN_DEVICE_ERROR The serial device could not be initialized.
- **/
- RETURN_STATUS
- EFIAPI
- SerialPortInitialize (
- VOID
- )
- {
- UINTN Divisor;
- UINT8 OutputData;
- UINT8 Data;
- //
- // Map 5..8 to 0..3
- //
- Data = (UINT8)(gData - (UINT8)5);
- //
- // Calculate divisor for baud generator
- //
- Divisor = 115200 / gBps;
- //
- // Set communications format
- //
- OutputData = (UINT8)((DLAB << 7) | (gBreakSet << 6) | (gParity << 3) | (gStop << 2) | Data);
- IoWrite8 (gUartBase + LCR_OFFSET, OutputData);
- //
- // Configure baud rate
- //
- IoWrite8 (gUartBase + BAUD_HIGH_OFFSET, (UINT8)(Divisor >> 8));
- IoWrite8 (gUartBase + BAUD_LOW_OFFSET, (UINT8)(Divisor & 0xff));
- //
- // Switch back to bank 0
- //
- OutputData = (UINT8)((gBreakSet << 6) | (gParity << 3) | (gStop << 2) | Data);
- IoWrite8 (gUartBase + LCR_OFFSET, OutputData);
- return RETURN_SUCCESS;
- }
- /**
- Write data from buffer to serial device.
- Writes NumberOfBytes data bytes from Buffer to the serial device.
- The number of bytes actually written to the serial device is returned.
- If the return value is less than NumberOfBytes, then the write operation failed.
- If Buffer is NULL, then ASSERT().
- If NumberOfBytes is zero, then return 0.
- @param Buffer Pointer to the data buffer to be written.
- @param NumberOfBytes Number of bytes to written to the serial device.
- @retval 0 NumberOfBytes is 0.
- @retval >0 The number of bytes written to the serial device.
- If this value is less than NumberOfBytes, then the write operation failed.
- **/
- UINTN
- EFIAPI
- SerialPortWrite (
- IN UINT8 *Buffer,
- IN UINTN NumberOfBytes
- )
- {
- UINTN Result;
- UINT8 Data;
- if (Buffer == NULL) {
- return 0;
- }
- Result = NumberOfBytes;
- while ((NumberOfBytes--) != 0) {
- //
- // Wait for the serial port to be ready.
- //
- do {
- Data = IoRead8 ((UINT16)gUartBase + LSR_OFFSET);
- } while ((Data & LSR_TXRDY) == 0);
- IoWrite8 ((UINT16)gUartBase, *Buffer++);
- }
- return Result;
- }
- /**
- Reads data from a serial device into a buffer.
- @param Buffer Pointer to the data buffer to store the data read from the serial device.
- @param NumberOfBytes Number of bytes to read from the serial device.
- @retval 0 NumberOfBytes is 0.
- @retval >0 The number of bytes read from the serial device.
- If this value is less than NumberOfBytes, then the read operation failed.
- **/
- UINTN
- EFIAPI
- SerialPortRead (
- OUT UINT8 *Buffer,
- IN UINTN NumberOfBytes
- )
- {
- UINTN Result;
- UINT8 Data;
- if (NULL == Buffer) {
- return 0;
- }
- Result = NumberOfBytes;
- while ((NumberOfBytes--) != 0) {
- //
- // Wait for the serial port to be ready.
- //
- do {
- Data = IoRead8 ((UINT16)gUartBase + LSR_OFFSET);
- } while ((Data & LSR_RXDA) == 0);
- *Buffer++ = IoRead8 ((UINT16)gUartBase);
- }
- return Result;
- }
- /**
- Polls a serial device to see if there is any data waiting to be read.
- Polls a serial device to see if there is any data waiting to be read.
- If there is data waiting to be read from the serial device, then TRUE is returned.
- If there is no data waiting to be read from the serial device, then FALSE is returned.
- @retval TRUE Data is waiting to be read from the serial device.
- @retval FALSE There is no data waiting to be read from the serial device.
- **/
- BOOLEAN
- EFIAPI
- SerialPortPoll (
- VOID
- )
- {
- UINT8 Data;
- //
- // Read the serial port status.
- //
- Data = IoRead8 ((UINT16)gUartBase + LSR_OFFSET);
- return (BOOLEAN)((Data & LSR_RXDA) != 0);
- }
- /**
- Sets the control bits on a serial device.
- @param Control Sets the bits of Control that are settable.
- @retval RETURN_SUCCESS The new control bits were set on the serial device.
- @retval RETURN_UNSUPPORTED The serial device does not support this operation.
- @retval RETURN_DEVICE_ERROR The serial device is not functioning correctly.
- **/
- RETURN_STATUS
- EFIAPI
- SerialPortSetControl (
- IN UINT32 Control
- )
- {
- UINT8 Mcr;
- //
- // First determine the parameter is invalid.
- //
- if ((Control & (~(EFI_SERIAL_REQUEST_TO_SEND | EFI_SERIAL_DATA_TERMINAL_READY))) != 0) {
- return RETURN_UNSUPPORTED;
- }
- //
- // Read the Modem Control Register.
- //
- Mcr = IoRead8 ((UINT16)gUartBase + MCR_OFFSET);
- Mcr &= (~(MCR_DTRC | MCR_RTS));
- if ((Control & EFI_SERIAL_DATA_TERMINAL_READY) == EFI_SERIAL_DATA_TERMINAL_READY) {
- Mcr |= MCR_DTRC;
- }
- if ((Control & EFI_SERIAL_REQUEST_TO_SEND) == EFI_SERIAL_REQUEST_TO_SEND) {
- Mcr |= MCR_RTS;
- }
- //
- // Write the Modem Control Register.
- //
- IoWrite8 ((UINT16)gUartBase + MCR_OFFSET, Mcr);
- return RETURN_SUCCESS;
- }
- /**
- Retrieve the status of the control bits on a serial device.
- @param Control A pointer to return the current control signals from the serial device.
- @retval RETURN_SUCCESS The control bits were read from the serial device.
- @retval RETURN_UNSUPPORTED The serial device does not support this operation.
- @retval RETURN_DEVICE_ERROR The serial device is not functioning correctly.
- **/
- RETURN_STATUS
- EFIAPI
- SerialPortGetControl (
- OUT UINT32 *Control
- )
- {
- UINT8 Msr;
- UINT8 Mcr;
- UINT8 Lsr;
- *Control = 0;
- //
- // Read the Modem Status Register.
- //
- Msr = IoRead8 ((UINT16)gUartBase + MSR_OFFSET);
- if ((Msr & MSR_CTS) == MSR_CTS) {
- *Control |= EFI_SERIAL_CLEAR_TO_SEND;
- }
- if ((Msr & MSR_DSR) == MSR_DSR) {
- *Control |= EFI_SERIAL_DATA_SET_READY;
- }
- if ((Msr & MSR_RI) == MSR_RI) {
- *Control |= EFI_SERIAL_RING_INDICATE;
- }
- if ((Msr & MSR_DCD) == MSR_DCD) {
- *Control |= EFI_SERIAL_CARRIER_DETECT;
- }
- //
- // Read the Modem Control Register.
- //
- Mcr = IoRead8 ((UINT16)gUartBase + MCR_OFFSET);
- if ((Mcr & MCR_DTRC) == MCR_DTRC) {
- *Control |= EFI_SERIAL_DATA_TERMINAL_READY;
- }
- if ((Mcr & MCR_RTS) == MCR_RTS) {
- *Control |= EFI_SERIAL_REQUEST_TO_SEND;
- }
- //
- // Read the Line Status Register.
- //
- Lsr = IoRead8 ((UINT16)gUartBase + LSR_OFFSET);
- if ((Lsr & LSR_TXRDY) == LSR_TXRDY) {
- *Control |= EFI_SERIAL_OUTPUT_BUFFER_EMPTY;
- }
- if ((Lsr & LSR_RXDA) == 0) {
- *Control |= EFI_SERIAL_INPUT_BUFFER_EMPTY;
- }
- return RETURN_SUCCESS;
- }
- /**
- Sets the baud rate, receive FIFO depth, transmit/receive time out, parity,
- data bits, and stop bits on a serial device.
- @param BaudRate The requested baud rate. A BaudRate value of 0 will use the
- device's default interface speed.
- On output, the value actually set.
- @param ReceiveFifoDepth The requested depth of the FIFO on the receive side of the
- serial interface. A ReceiveFifoDepth value of 0 will use
- the device's default FIFO depth.
- On output, the value actually set.
- @param Timeout The requested time out for a single character in microseconds.
- This timeout applies to both the transmit and receive side of the
- interface. A Timeout value of 0 will use the device's default time
- out value.
- On output, the value actually set.
- @param Parity The type of parity to use on this serial device. A Parity value of
- DefaultParity will use the device's default parity value.
- On output, the value actually set.
- @param DataBits The number of data bits to use on the serial device. A DataBits
- value of 0 will use the device's default data bit setting.
- On output, the value actually set.
- @param StopBits The number of stop bits to use on this serial device. A StopBits
- value of DefaultStopBits will use the device's default number of
- stop bits.
- On output, the value actually set.
- @retval RETURN_SUCCESS The new attributes were set on the serial device.
- @retval RETURN_UNSUPPORTED The serial device does not support this operation.
- @retval RETURN_INVALID_PARAMETER One or more of the attributes has an unsupported value.
- @retval RETURN_DEVICE_ERROR The serial device is not functioning correctly.
- **/
- RETURN_STATUS
- EFIAPI
- SerialPortSetAttributes (
- IN OUT UINT64 *BaudRate,
- IN OUT UINT32 *ReceiveFifoDepth,
- IN OUT UINT32 *Timeout,
- IN OUT EFI_PARITY_TYPE *Parity,
- IN OUT UINT8 *DataBits,
- IN OUT EFI_STOP_BITS_TYPE *StopBits
- )
- {
- UINTN Divisor;
- UINT8 OutputData;
- UINT8 LcrData;
- UINT8 LcrParity;
- UINT8 LcrStop;
- //
- // Check for default settings and fill in actual values.
- //
- if (*BaudRate == 0) {
- *BaudRate = gBps;
- }
- if (*DataBits == 0) {
- *DataBits = gData;
- }
- if (*Parity == DefaultParity) {
- *Parity = NoParity;
- }
- if (*StopBits == DefaultStopBits) {
- *StopBits = OneStopBit;
- }
- if ((*DataBits < 5) || (*DataBits > 8)) {
- return RETURN_INVALID_PARAMETER;
- }
- //
- // Map 5..8 to 0..3
- //
- LcrData = (UINT8)(*DataBits - (UINT8)5);
- switch (*Parity) {
- case NoParity:
- LcrParity = 0;
- break;
- case EvenParity:
- LcrParity = 3;
- break;
- case OddParity:
- LcrParity = 1;
- break;
- case SpaceParity:
- LcrParity = 7;
- break;
- case MarkParity:
- LcrParity = 5;
- break;
- default:
- return RETURN_INVALID_PARAMETER;
- }
- switch (*StopBits) {
- case OneStopBit:
- LcrStop = 0;
- break;
- case OneFiveStopBits:
- case TwoStopBits:
- LcrStop = 1;
- break;
- default:
- return RETURN_INVALID_PARAMETER;
- }
- //
- // Calculate divisor for baud generator
- //
- Divisor = 115200 / (UINTN)*BaudRate;
- //
- // Set communications format
- //
- OutputData = (UINT8)((DLAB << 7) | (gBreakSet << 6) | (LcrParity << 3) | (LcrStop << 2) | LcrData);
- IoWrite8 (gUartBase + LCR_OFFSET, OutputData);
- //
- // Configure baud rate
- //
- IoWrite8 (gUartBase + BAUD_HIGH_OFFSET, (UINT8)(Divisor >> 8));
- IoWrite8 (gUartBase + BAUD_LOW_OFFSET, (UINT8)(Divisor & 0xff));
- //
- // Switch back to bank 0
- //
- OutputData = (UINT8)((gBreakSet << 6) | (LcrParity << 3) | (LcrStop << 2) | LcrData);
- IoWrite8 (gUartBase + LCR_OFFSET, OutputData);
- return RETURN_SUCCESS;
- }
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