mirror of https://github.com/acidanthera/audk.git
400 lines
12 KiB
C
400 lines
12 KiB
C
/** @file
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16550 UART Serial Port library functions
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Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <Base.h>
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#include <Library/SerialPortLib.h>
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#include <Library/PcdLib.h>
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#include <Library/IoLib.h>
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#include <Library/PlatformHookLib.h>
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//
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// 16550 UART register offsets and bitfields
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//
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#define R_UART_RXBUF 0
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#define R_UART_TXBUF 0
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#define R_UART_BAUD_LOW 0
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#define R_UART_BAUD_HIGH 1
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#define R_UART_FCR 2
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#define B_UART_FCR_FIFOE BIT0
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#define B_UART_FCR_FIFO64 BIT5
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#define R_UART_LCR 3
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#define B_UART_LCR_DLAB BIT7
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#define R_UART_MCR 4
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#define B_UART_MCR_RTS BIT1
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#define R_UART_LSR 5
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#define B_UART_LSR_RXRDY BIT0
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#define B_UART_LSR_TXRDY BIT5
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#define B_UART_LSR_TEMT BIT6
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#define R_UART_MSR 6
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#define B_UART_MSR_CTS BIT4
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#define B_UART_MSR_DSR BIT5
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/**
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Read an 8-bit 16550 register. If PcdSerialUseMmio is TRUE, then the value is read from
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MMIO space. If PcdSerialUseMmio is FALSE, then the value is read from I/O space. The
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parameter Offset is added to the base address of the 16550 registers that is specified
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by PcdSerialRegisterBase.
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@param Offset The offset of the 16550 register to read.
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@return The value read from the 16550 register.
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**/
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UINT8
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SerialPortReadRegister (
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UINTN Offset
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)
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{
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if (PcdGetBool (PcdSerialUseMmio)) {
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return MmioRead8 ((UINTN)PcdGet64 (PcdSerialRegisterBase) + Offset);
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} else {
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return IoRead8 ((UINT16)PcdGet64 (PcdSerialRegisterBase) + Offset);
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}
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}
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/**
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Write an 8-bit 16550 register. If PcdSerialUseMmio is TRUE, then the value is written to
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MMIO space. If PcdSerialUseMmio is FALSE, then the value is written to I/O space. The
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parameter Offset is added to the base address of the 16550 registers that is specified
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by PcdSerialRegisterBase.
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@param Offset The offset of the 16550 register to write.
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@param Value The value to write to the 16550 register specified by Offset.
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@return The value written to the 16550 register.
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**/
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UINT8
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SerialPortWriteRegister (
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UINTN Offset,
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UINT8 Value
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)
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{
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if (PcdGetBool (PcdSerialUseMmio)) {
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return MmioWrite8 ((UINTN)PcdGet64 (PcdSerialRegisterBase) + Offset, Value);
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} else {
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return IoWrite8 ((UINT16)PcdGet64 (PcdSerialRegisterBase) + Offset, Value);
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}
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}
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/**
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Return whether the hardware flow control signal allows writing.
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@retval TRUE The serial port is writable.
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@retval FALSE The serial port is not writable.
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**/
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BOOLEAN
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SerialPortWritable (
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VOID
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)
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{
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if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
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if (PcdGetBool (PcdSerialDetectCable)) {
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//
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// Wait for both DSR and CTS to be set
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// DSR is set if a cable is connected.
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// CTS is set if it is ok to transmit data
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//
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// DSR CTS Description Action
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// === === ======================================== ========
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// 0 0 No cable connected. Wait
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// 0 1 No cable connected. Wait
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// 1 0 Cable connected, but not clear to send. Wait
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// 1 1 Cable connected, and clear to send. Transmit
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//
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return (BOOLEAN) ((SerialPortReadRegister (R_UART_MSR) & (B_UART_MSR_DSR | B_UART_MSR_CTS)) == (B_UART_MSR_DSR | B_UART_MSR_CTS));
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} else {
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//
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// Wait for both DSR and CTS to be set OR for DSR to be clear.
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// DSR is set if a cable is connected.
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// CTS is set if it is ok to transmit data
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//
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// DSR CTS Description Action
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// === === ======================================== ========
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// 0 0 No cable connected. Transmit
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// 0 1 No cable connected. Transmit
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// 1 0 Cable connected, but not clear to send. Wait
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// 1 1 Cable connected, and clar to send. Transmit
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//
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return (BOOLEAN) ((SerialPortReadRegister (R_UART_MSR) & (B_UART_MSR_DSR | B_UART_MSR_CTS)) != (B_UART_MSR_DSR));
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}
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}
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return TRUE;
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}
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/**
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Initialize the serial device hardware.
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If no initialization is required, then return RETURN_SUCCESS.
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If the serial device was successfully initialized, then return RETURN_SUCCESS.
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If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.
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@retval RETURN_SUCCESS The serial device was initialized.
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@retval RETURN_DEVICE_ERROR The serial device could not be initialized.
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**/
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RETURN_STATUS
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EFIAPI
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SerialPortInitialize (
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VOID
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)
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{
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RETURN_STATUS Status;
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UINTN Divisor;
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BOOLEAN Initialized;
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//
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// Perform platform specific initialization required to enable use of the 16550 device
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// at the location specified by PcdSerialUseMmio and PcdSerialRegisterBase.
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//
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Status = PlatformHookSerialPortInitialize ();
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if (RETURN_ERROR (Status)) {
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return Status;
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}
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//
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// See if the serial port is already initialized
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//
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Initialized = TRUE;
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if ((SerialPortReadRegister (R_UART_FCR) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)) !=
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(PcdGet8 (PcdSerialFifoControl) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)) ) {
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Initialized = FALSE;
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}
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if ((SerialPortReadRegister (R_UART_LCR) & 0x3F) != (PcdGet8 (PcdSerialLineControl) & 0x3F)) {
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Initialized = FALSE;
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}
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SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) | B_UART_LCR_DLAB));
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Divisor = SerialPortReadRegister (R_UART_BAUD_HIGH) << 8;
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Divisor |= SerialPortReadRegister (R_UART_BAUD_LOW);
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SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) & ~B_UART_LCR_DLAB));
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if (Divisor != 115200 / PcdGet32 (PcdSerialBaudRate)) {
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Initialized = FALSE;
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}
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if (Initialized) {
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return RETURN_SUCCESS;
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}
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//
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// Configure baud rate
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//
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Divisor = 115200 / PcdGet32 (PcdSerialBaudRate);
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SerialPortWriteRegister (R_UART_LCR, B_UART_LCR_DLAB);
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SerialPortWriteRegister (R_UART_BAUD_HIGH, (UINT8) (Divisor >> 8));
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SerialPortWriteRegister (R_UART_BAUD_LOW, (UINT8) (Divisor & 0xff));
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//
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// Clear DLAB and configure Data Bits, Parity, and Stop Bits.
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// Strip reserved bits from PcdSerialLineControl
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//
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SerialPortWriteRegister (R_UART_LCR, (UINT8)(PcdGet8 (PcdSerialLineControl) & 0x3F));
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//
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// Enable and reset FIFOs
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// Strip reserved bits from PcdSerialFifoControl
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//
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SerialPortWriteRegister (R_UART_FCR, (UINT8)(PcdGet8 (PcdSerialFifoControl) & 0x27));
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//
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// Put Modem Control Register(MCR) into its reset state of 0x00.
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//
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SerialPortWriteRegister (R_UART_MCR, 0x00);
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return RETURN_SUCCESS;
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}
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/**
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Write data from buffer to serial device.
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Writes NumberOfBytes data bytes from Buffer to the serial device.
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The number of bytes actually written to the serial device is returned.
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If the return value is less than NumberOfBytes, then the write operation failed.
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If Buffer is NULL, then ASSERT().
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If NumberOfBytes is zero, then return 0.
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@param Buffer Pointer to the data buffer to be written.
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@param NumberOfBytes Number of bytes to written to the serial device.
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@retval 0 NumberOfBytes is 0.
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@retval >0 The number of bytes written to the serial device.
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If this value is less than NumberOfBytes, then the read operation failed.
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**/
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UINTN
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EFIAPI
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SerialPortWrite (
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IN UINT8 *Buffer,
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IN UINTN NumberOfBytes
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)
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{
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UINTN Result;
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UINTN Index;
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UINTN FifoSize;
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if (Buffer == NULL) {
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return 0;
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}
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if (NumberOfBytes == 0) {
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//
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// Flush the hardware
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//
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//
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// Wait for both the transmit FIFO and shift register empty.
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//
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while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);
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//
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// Wait for the hardware flow control signal
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//
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while (!SerialPortWritable ());
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return 0;
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}
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//
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// Compute the maximum size of the Tx FIFO
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//
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FifoSize = 1;
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if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFOE) != 0) {
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if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFO64) == 0) {
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FifoSize = 16;
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} else {
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FifoSize = 64;
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}
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}
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Result = NumberOfBytes;
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while (NumberOfBytes != 0) {
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//
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// Wait for the serial port to be ready, to make sure both the transmit FIFO
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// and shift register empty.
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//
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while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);
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//
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// Fill then entire Tx FIFO
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//
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for (Index = 0; Index < FifoSize && NumberOfBytes != 0; Index++, NumberOfBytes--, Buffer++) {
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//
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// Wait for the hardware flow control signal
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//
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while (!SerialPortWritable ());
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//
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// Write byte to the transmit buffer.
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//
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SerialPortWriteRegister (R_UART_TXBUF, *Buffer);
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}
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}
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return Result;
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}
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/**
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Reads data from a serial device into a buffer.
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@param Buffer Pointer to the data buffer to store the data read from the serial device.
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@param NumberOfBytes Number of bytes to read from the serial device.
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@retval 0 NumberOfBytes is 0.
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@retval >0 The number of bytes read from the serial device.
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If this value is less than NumberOfBytes, then the read operation failed.
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**/
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UINTN
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EFIAPI
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SerialPortRead (
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OUT UINT8 *Buffer,
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IN UINTN NumberOfBytes
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)
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{
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UINTN Result;
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UINT8 Mcr;
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if (NULL == Buffer) {
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return 0;
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}
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Mcr = (UINT8)(SerialPortReadRegister (R_UART_MCR) & ~B_UART_MCR_RTS);
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for (Result = 0; NumberOfBytes-- != 0; Result++, Buffer++) {
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//
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// Wait for the serial port to have some data.
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//
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while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) == 0) {
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if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
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//
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// Set RTS to let the peer send some data
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//
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SerialPortWriteRegister (R_UART_MCR, (UINT8)(Mcr | B_UART_MCR_RTS));
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}
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}
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if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
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//
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// Clear RTS to prevent peer from sending data
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//
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SerialPortWriteRegister (R_UART_MCR, Mcr);
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}
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//
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// Read byte from the receive buffer.
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//
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*Buffer = SerialPortReadRegister (R_UART_RXBUF);
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}
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return Result;
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}
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/**
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Polls a serial device to see if there is any data waiting to be read.
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Polls aserial device to see if there is any data waiting to be read.
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If there is data waiting to be read from the serial device, then TRUE is returned.
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If there is no data waiting to be read from the serial device, then FALSE is returned.
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@retval TRUE Data is waiting to be read from the serial device.
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@retval FALSE There is no data waiting to be read from the serial device.
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**/
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BOOLEAN
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EFIAPI
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SerialPortPoll (
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VOID
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)
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{
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//
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// Read the serial port status
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//
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if ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) != 0) {
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if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
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//
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// Clear RTS to prevent peer from sending data
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//
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SerialPortWriteRegister (R_UART_MCR, (UINT8)(SerialPortReadRegister (R_UART_MCR) & ~B_UART_MCR_RTS));
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}
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return TRUE;
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}
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if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
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//
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// Set RTS to let the peer send some data
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//
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SerialPortWriteRegister (R_UART_MCR, (UINT8)(SerialPortReadRegister (R_UART_MCR) | B_UART_MCR_RTS));
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}
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return FALSE;
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}
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