[mirror_edk2.git] / MdeModulePkg / Library / BaseSerialPortLib16550 / BaseSerialPortLib16550.c

/** @file\r
  16550 UART Serial Port library functions\r
\r
  Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include <Base.h>\r
#include <Library/SerialPortLib.h>\r
#include <Library/PcdLib.h>\r
#include <Library/IoLib.h>\r
#include <Library/PlatformHookLib.h>\r
\r
//\r
// 16550 UART register offsets and bitfields\r
//\r
#define R_UART_RXBUF          0\r
#define R_UART_TXBUF          0\r
#define R_UART_BAUD_LOW       0\r
#define R_UART_BAUD_HIGH      1\r
#define R_UART_FCR            2\r
#define   B_UART_FCR_FIFOE    BIT0\r
#define   B_UART_FCR_FIFO64   BIT5\r
#define R_UART_LCR            3\r
#define   B_UART_LCR_DLAB     BIT7\r
#define R_UART_MCR            4\r
#define   B_UART_MCR_RTS      BIT1\r
#define R_UART_LSR            5\r
#define   B_UART_LSR_RXRDY    BIT0\r
#define   B_UART_LSR_TXRDY    BIT5\r
#define   B_UART_LSR_TEMT     BIT6\r
#define R_UART_MSR            6\r
#define   B_UART_MSR_CTS      BIT4\r
#define   B_UART_MSR_DSR      BIT5\r
\r
/**\r
  Read an 8-bit 16550 register.  If PcdSerialUseMmio is TRUE, then the value is read from \r
  MMIO space.  If PcdSerialUseMmio is FALSE, then the value is read from I/O space.  The\r
  parameter Offset is added to the base address of the 16550 registers that is specified \r
  by PcdSerialRegisterBase. \r
  \r
  @param  Offset  The offset of the 16550 register to read.\r
\r
  @return The value read from the 16550 register.\r
\r
**/\r
UINT8\r
SerialPortReadRegister (\r
  UINTN  Offset\r
  )\r
{\r
  if (PcdGetBool (PcdSerialUseMmio)) {\r
    return MmioRead8 ((UINTN)PcdGet64 (PcdSerialRegisterBase) + Offset);\r
  } else {\r
    return IoRead8 ((UINT16)PcdGet64 (PcdSerialRegisterBase) + Offset);\r
  }\r
}\r
\r
/**\r
  Write an 8-bit 16550 register.  If PcdSerialUseMmio is TRUE, then the value is written to\r
  MMIO space.  If PcdSerialUseMmio is FALSE, then the value is written to I/O space.  The\r
  parameter Offset is added to the base address of the 16550 registers that is specified \r
  by PcdSerialRegisterBase. \r
  \r
  @param  Offset  The offset of the 16550 register to write.\r
  @param  Value   The value to write to the 16550 register specified by Offset.\r
\r
  @return The value written to the 16550 register.\r
\r
**/\r
UINT8\r
SerialPortWriteRegister (\r
  UINTN  Offset,\r
  UINT8  Value\r
  )\r
{\r
  if (PcdGetBool (PcdSerialUseMmio)) {\r
    return MmioWrite8 ((UINTN)PcdGet64 (PcdSerialRegisterBase) + Offset, Value);\r
  } else {\r
    return IoWrite8 ((UINT16)PcdGet64 (PcdSerialRegisterBase) + Offset, Value);\r
  }\r
}\r
\r
/**\r
  Return whether the hardware flow control signal allows writing.\r
\r
  @retval TRUE  The serial port is writable.\r
  @retval FALSE The serial port is not writable.\r
**/\r
BOOLEAN\r
SerialPortWritable (\r
  VOID\r
  )\r
{\r
  if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
    if (PcdGetBool (PcdSerialDetectCable)) {\r
      //\r
      // Wait for both DSR and CTS to be set\r
      //   DSR is set if a cable is connected.\r
      //   CTS is set if it is ok to transmit data\r
      //\r
      //   DSR  CTS  Description                               Action\r
      //   ===  ===  ========================================  ========\r
      //    0    0   No cable connected.                       Wait\r
      //    0    1   No cable connected.                       Wait\r
      //    1    0   Cable connected, but not clear to send.   Wait\r
      //    1    1   Cable connected, and clear to send.       Transmit\r
      //\r
      return (BOOLEAN) ((SerialPortReadRegister (R_UART_MSR) & (B_UART_MSR_DSR | B_UART_MSR_CTS)) == (B_UART_MSR_DSR | B_UART_MSR_CTS));\r
    } else {\r
      //\r
      // Wait for both DSR and CTS to be set OR for DSR to be clear.  \r
      //   DSR is set if a cable is connected.\r
      //   CTS is set if it is ok to transmit data\r
      //\r
      //   DSR  CTS  Description                               Action\r
      //   ===  ===  ========================================  ========\r
      //    0    0   No cable connected.                       Transmit\r
      //    0    1   No cable connected.                       Transmit\r
      //    1    0   Cable connected, but not clear to send.   Wait\r
      //    1    1   Cable connected, and clar to send.        Transmit\r
      //\r
      return (BOOLEAN) ((SerialPortReadRegister (R_UART_MSR) & (B_UART_MSR_DSR | B_UART_MSR_CTS)) != (B_UART_MSR_DSR));\r
    }\r
  }\r
\r
  return TRUE;\r
}\r
\r
/**\r
  Initialize the serial device hardware.\r
  \r
  If no initialization is required, then return RETURN_SUCCESS.\r
  If the serial device was successfully initialized, then return RETURN_SUCCESS.\r
  If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.\r
  \r
  @retval RETURN_SUCCESS        The serial device was initialized.\r
  @retval RETURN_DEVICE_ERROR   The serial device could not be initialized.\r
\r
**/\r
RETURN_STATUS\r
EFIAPI\r
SerialPortInitialize (\r
  VOID\r
  )\r
{\r
  RETURN_STATUS  Status;\r
  UINTN          Divisor;\r
  BOOLEAN        Initialized;\r
\r
  //\r
  // Perform platform specific initialization required to enable use of the 16550 device\r
  // at the location specified by PcdSerialUseMmio and PcdSerialRegisterBase.\r
  //\r
  Status = PlatformHookSerialPortInitialize ();\r
  if (RETURN_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  //\r
  // See if the serial port is already initialized\r
  //\r
  Initialized = TRUE;\r
  if ((SerialPortReadRegister (R_UART_FCR) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)) !=\r
      (PcdGet8 (PcdSerialFifoControl)      & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64))     ) {\r
    Initialized = FALSE;\r
  }\r
  if ((SerialPortReadRegister (R_UART_LCR) & 0x3F) != (PcdGet8 (PcdSerialLineControl) & 0x3F)) {\r
    Initialized = FALSE;\r
  }\r
  SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) | B_UART_LCR_DLAB));\r
  Divisor =  SerialPortReadRegister (R_UART_BAUD_HIGH) << 8;\r
  Divisor |= (UINTN)SerialPortReadRegister (R_UART_BAUD_LOW);\r
  SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) & ~B_UART_LCR_DLAB));\r
  if (Divisor != 115200 / PcdGet32 (PcdSerialBaudRate)) {\r
    Initialized = FALSE;\r
  }\r
  if (Initialized) {\r
    return RETURN_SUCCESS;\r
  }\r
  \r
  //\r
  // Configure baud rate\r
  //\r
  Divisor = 115200 / PcdGet32 (PcdSerialBaudRate);\r
  SerialPortWriteRegister (R_UART_LCR, B_UART_LCR_DLAB);\r
  SerialPortWriteRegister (R_UART_BAUD_HIGH, (UINT8) (Divisor >> 8));\r
  SerialPortWriteRegister (R_UART_BAUD_LOW, (UINT8) (Divisor & 0xff));\r
\r
  //\r
  // Clear DLAB and configure Data Bits, Parity, and Stop Bits.\r
  // Strip reserved bits from PcdSerialLineControl\r
  //\r
  SerialPortWriteRegister (R_UART_LCR, (UINT8)(PcdGet8 (PcdSerialLineControl) & 0x3F));\r
\r
  //\r
  // Enable and reset FIFOs\r
  // Strip reserved bits from PcdSerialFifoControl\r
  //\r
  SerialPortWriteRegister (R_UART_FCR, (UINT8)(PcdGet8 (PcdSerialFifoControl) & 0x27));\r
\r
  //\r
  // Put Modem Control Register(MCR) into its reset state of 0x00.\r
  //  \r
  SerialPortWriteRegister (R_UART_MCR, 0x00);\r
  \r
  return RETURN_SUCCESS;\r
}\r
\r
/**\r
  Write data from buffer to serial device. \r
 \r
  Writes NumberOfBytes data bytes from Buffer to the serial device.  \r
  The number of bytes actually written to the serial device is returned.\r
  If the return value is less than NumberOfBytes, then the write operation failed.\r
\r
  If Buffer is NULL, then ASSERT(). \r
\r
  If NumberOfBytes is zero, then return 0.\r
\r
  @param  Buffer           Pointer to the data buffer to be written.\r
  @param  NumberOfBytes    Number of bytes to written to the serial device.\r
\r
  @retval 0                NumberOfBytes is 0.\r
  @retval >0               The number of bytes written to the serial device.  \r
                           If this value is less than NumberOfBytes, then the read operation failed.\r
\r
**/\r
UINTN\r
EFIAPI\r
SerialPortWrite (\r
  IN UINT8     *Buffer,\r
  IN UINTN     NumberOfBytes\r
)\r
{\r
  UINTN    Result;\r
  UINTN    Index;\r
  UINTN    FifoSize;\r
\r
  if (Buffer == NULL) {\r
    return 0;\r
  }\r
\r
  if (NumberOfBytes == 0) {\r
    //\r
    // Flush the hardware\r
    //\r
\r
    //\r
    // Wait for both the transmit FIFO and shift register empty.\r
    //\r
    while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);\r
\r
    //\r
    // Wait for the hardware flow control signal\r
    //\r
    while (!SerialPortWritable ());\r
    return 0;\r
  }\r
\r
  //\r
  // Compute the maximum size of the Tx FIFO\r
  //\r
  FifoSize = 1;\r
  if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFOE) != 0) {\r
    if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFO64) == 0) {\r
      FifoSize = 16;\r
    } else {\r
      FifoSize = 64;\r
    }\r
  }\r
\r
  Result = NumberOfBytes;\r
  while (NumberOfBytes != 0) {\r
    //\r
    // Wait for the serial port to be ready, to make sure both the transmit FIFO\r
    // and shift register empty.\r
    //\r
    while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);\r
\r
    //\r
    // Fill then entire Tx FIFO\r
    //\r
    for (Index = 0; Index < FifoSize && NumberOfBytes != 0; Index++, NumberOfBytes--, Buffer++) {\r
      //\r
      // Wait for the hardware flow control signal\r
      //\r
      while (!SerialPortWritable ());\r
\r
      //\r
      // Write byte to the transmit buffer.\r
      //\r
      SerialPortWriteRegister (R_UART_TXBUF, *Buffer);\r
    }\r
  }\r
  return Result;\r
}\r
\r
/**\r
  Reads data from a serial device into a buffer.\r
\r
  @param  Buffer           Pointer to the data buffer to store the data read from the serial device.\r
  @param  NumberOfBytes    Number of bytes to read from the serial device.\r
\r
  @retval 0                NumberOfBytes is 0.\r
  @retval >0               The number of bytes read from the serial device.  \r
                           If this value is less than NumberOfBytes, then the read operation failed.\r
\r
**/\r
UINTN\r
EFIAPI\r
SerialPortRead (\r
  OUT UINT8     *Buffer,\r
  IN  UINTN     NumberOfBytes\r
)\r
{\r
  UINTN  Result;\r
  UINT8  Mcr;\r
\r
  if (NULL == Buffer) {\r
    return 0;\r
  }\r
\r
  Mcr = (UINT8)(SerialPortReadRegister (R_UART_MCR) & ~B_UART_MCR_RTS);\r
  \r
  for (Result = 0; NumberOfBytes-- != 0; Result++, Buffer++) {\r
    //\r
    // Wait for the serial port to have some data.\r
    //\r
    while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) == 0) {\r
      if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
        //\r
        // Set RTS to let the peer send some data\r
        //\r
        SerialPortWriteRegister (R_UART_MCR, (UINT8)(Mcr | B_UART_MCR_RTS));\r
      }\r
    }\r
    if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
      //\r
      // Clear RTS to prevent peer from sending data\r
      //\r
      SerialPortWriteRegister (R_UART_MCR, Mcr);\r
    }\r
    \r
    //\r
    // Read byte from the receive buffer.\r
    //\r
    *Buffer = SerialPortReadRegister (R_UART_RXBUF);\r
  }\r
  \r
  return Result;\r
}\r
\r
/**\r
  Polls a serial device to see if there is any data waiting to be read.\r
\r
  Polls aserial device to see if there is any data waiting to be read.\r
  If there is data waiting to be read from the serial device, then TRUE is returned.\r
  If there is no data waiting to be read from the serial device, then FALSE is returned.\r
\r
  @retval TRUE             Data is waiting to be read from the serial device.\r
  @retval FALSE            There is no data waiting to be read from the serial device.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
SerialPortPoll (\r
  VOID\r
  )\r
{\r
  //\r
  // Read the serial port status\r
  //\r
  if ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) != 0) {\r
    if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
      //\r
      // Clear RTS to prevent peer from sending data\r
      //\r
      SerialPortWriteRegister (R_UART_MCR, (UINT8)(SerialPortReadRegister (R_UART_MCR) & ~B_UART_MCR_RTS));\r
    }\r
    return TRUE;\r
  }    \r
  \r
  if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
    //\r
    // Set RTS to let the peer send some data\r
    //\r
    SerialPortWriteRegister (R_UART_MCR, (UINT8)(SerialPortReadRegister (R_UART_MCR) | B_UART_MCR_RTS));\r
  }\r
  \r
  return FALSE;\r
}\r
Commit	Line	Data
	1	/** @file\r
	2	16550 UART Serial Port library functions\r
	3	\r
	4	Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>\r
	5	This program and the accompanying materials\r
	6	are licensed and made available under the terms and conditions of the BSD License\r
	7	which accompanies this distribution. The full text of the license may be found at\r
	8	http://opensource.org/licenses/bsd-license.php\r
	9	\r
	10	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	11	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	\r
	13	**/\r
	14	\r
	15	#include <Base.h>\r
	16	#include <Library/SerialPortLib.h>\r
	17	#include <Library/PcdLib.h>\r
	18	#include <Library/IoLib.h>\r
	19	#include <Library/PlatformHookLib.h>\r
	20	\r
	21	//\r
	22	// 16550 UART register offsets and bitfields\r
	23	//\r
	24	#define R_UART_RXBUF 0\r
	25	#define R_UART_TXBUF 0\r
	26	#define R_UART_BAUD_LOW 0\r
	27	#define R_UART_BAUD_HIGH 1\r
	28	#define R_UART_FCR 2\r
	29	#define B_UART_FCR_FIFOE BIT0\r
	30	#define B_UART_FCR_FIFO64 BIT5\r
	31	#define R_UART_LCR 3\r
	32	#define B_UART_LCR_DLAB BIT7\r
	33	#define R_UART_MCR 4\r
	34	#define B_UART_MCR_RTS BIT1\r
	35	#define R_UART_LSR 5\r
	36	#define B_UART_LSR_RXRDY BIT0\r
	37	#define B_UART_LSR_TXRDY BIT5\r
	38	#define B_UART_LSR_TEMT BIT6\r
	39	#define R_UART_MSR 6\r
	40	#define B_UART_MSR_CTS BIT4\r
	41	#define B_UART_MSR_DSR BIT5\r
	42	\r
	43	/**\r
	44	Read an 8-bit 16550 register. If PcdSerialUseMmio is TRUE, then the value is read from \r
	45	MMIO space. If PcdSerialUseMmio is FALSE, then the value is read from I/O space. The\r
	46	parameter Offset is added to the base address of the 16550 registers that is specified \r
	47	by PcdSerialRegisterBase. \r
	48	\r
	49	@param Offset The offset of the 16550 register to read.\r
	50	\r
	51	@return The value read from the 16550 register.\r
	52	\r
	53	**/\r
	54	UINT8\r
	55	SerialPortReadRegister (\r
	56	UINTN Offset\r
	57	)\r
	58	{\r
	59	if (PcdGetBool (PcdSerialUseMmio)) {\r
	60	return MmioRead8 ((UINTN)PcdGet64 (PcdSerialRegisterBase) + Offset);\r
	61	} else {\r
	62	return IoRead8 ((UINT16)PcdGet64 (PcdSerialRegisterBase) + Offset);\r
	63	}\r
	64	}\r
	65	\r
	66	/**\r
	67	Write an 8-bit 16550 register. If PcdSerialUseMmio is TRUE, then the value is written to\r
	68	MMIO space. If PcdSerialUseMmio is FALSE, then the value is written to I/O space. The\r
	69	parameter Offset is added to the base address of the 16550 registers that is specified \r
	70	by PcdSerialRegisterBase. \r
	71	\r
	72	@param Offset The offset of the 16550 register to write.\r
	73	@param Value The value to write to the 16550 register specified by Offset.\r
	74	\r
	75	@return The value written to the 16550 register.\r
	76	\r
	77	**/\r
	78	UINT8\r
	79	SerialPortWriteRegister (\r
	80	UINTN Offset,\r
	81	UINT8 Value\r
	82	)\r
	83	{\r
	84	if (PcdGetBool (PcdSerialUseMmio)) {\r
	85	return MmioWrite8 ((UINTN)PcdGet64 (PcdSerialRegisterBase) + Offset, Value);\r
	86	} else {\r
	87	return IoWrite8 ((UINT16)PcdGet64 (PcdSerialRegisterBase) + Offset, Value);\r
	88	}\r
	89	}\r
	90	\r
	91	/**\r
	92	Return whether the hardware flow control signal allows writing.\r
	93	\r
	94	@retval TRUE The serial port is writable.\r
	95	@retval FALSE The serial port is not writable.\r
	96	**/\r
	97	BOOLEAN\r
	98	SerialPortWritable (\r
	99	VOID\r
	100	)\r
	101	{\r
	102	if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
	103	if (PcdGetBool (PcdSerialDetectCable)) {\r
	104	//\r
	105	// Wait for both DSR and CTS to be set\r
	106	// DSR is set if a cable is connected.\r
	107	// CTS is set if it is ok to transmit data\r
	108	//\r
	109	// DSR CTS Description Action\r
	110	// === === ======================================== ========\r
	111	// 0 0 No cable connected. Wait\r
	112	// 0 1 No cable connected. Wait\r
	113	// 1 0 Cable connected, but not clear to send. Wait\r
	114	// 1 1 Cable connected, and clear to send. Transmit\r
	115	//\r
	116	return (BOOLEAN) ((SerialPortReadRegister (R_UART_MSR) & (B_UART_MSR_DSR \| B_UART_MSR_CTS)) == (B_UART_MSR_DSR \| B_UART_MSR_CTS));\r
	117	} else {\r
	118	//\r
	119	// Wait for both DSR and CTS to be set OR for DSR to be clear. \r
	120	// DSR is set if a cable is connected.\r
	121	// CTS is set if it is ok to transmit data\r
	122	//\r
	123	// DSR CTS Description Action\r
	124	// === === ======================================== ========\r
	125	// 0 0 No cable connected. Transmit\r
	126	// 0 1 No cable connected. Transmit\r
	127	// 1 0 Cable connected, but not clear to send. Wait\r
	128	// 1 1 Cable connected, and clar to send. Transmit\r
	129	//\r
	130	return (BOOLEAN) ((SerialPortReadRegister (R_UART_MSR) & (B_UART_MSR_DSR \| B_UART_MSR_CTS)) != (B_UART_MSR_DSR));\r
	131	}\r
	132	}\r
	133	\r
	134	return TRUE;\r
	135	}\r
	136	\r
	137	/**\r
	138	Initialize the serial device hardware.\r
	139	\r
	140	If no initialization is required, then return RETURN_SUCCESS.\r
	141	If the serial device was successfully initialized, then return RETURN_SUCCESS.\r
	142	If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.\r
	143	\r
	144	@retval RETURN_SUCCESS The serial device was initialized.\r
	145	@retval RETURN_DEVICE_ERROR The serial device could not be initialized.\r
	146	\r
	147	**/\r
	148	RETURN_STATUS\r
	149	EFIAPI\r
	150	SerialPortInitialize (\r
	151	VOID\r
	152	)\r
	153	{\r
	154	RETURN_STATUS Status;\r
	155	UINTN Divisor;\r
	156	BOOLEAN Initialized;\r
	157	\r
	158	//\r
	159	// Perform platform specific initialization required to enable use of the 16550 device\r
	160	// at the location specified by PcdSerialUseMmio and PcdSerialRegisterBase.\r
	161	//\r
	162	Status = PlatformHookSerialPortInitialize ();\r
	163	if (RETURN_ERROR (Status)) {\r
	164	return Status;\r
	165	}\r
	166	\r
	167	//\r
	168	// See if the serial port is already initialized\r
	169	//\r
	170	Initialized = TRUE;\r
	171	if ((SerialPortReadRegister (R_UART_FCR) & (B_UART_FCR_FIFOE \| B_UART_FCR_FIFO64)) !=\r
	172	(PcdGet8 (PcdSerialFifoControl) & (B_UART_FCR_FIFOE \| B_UART_FCR_FIFO64)) ) {\r
	173	Initialized = FALSE;\r
	174	}\r
	175	if ((SerialPortReadRegister (R_UART_LCR) & 0x3F) != (PcdGet8 (PcdSerialLineControl) & 0x3F)) {\r
	176	Initialized = FALSE;\r
	177	}\r
	178	SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) \| B_UART_LCR_DLAB));\r
	179	Divisor = SerialPortReadRegister (R_UART_BAUD_HIGH) << 8;\r
	180	Divisor \|= (UINTN)SerialPortReadRegister (R_UART_BAUD_LOW);\r
	181	SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) & ~B_UART_LCR_DLAB));\r
	182	if (Divisor != 115200 / PcdGet32 (PcdSerialBaudRate)) {\r
	183	Initialized = FALSE;\r
	184	}\r
	185	if (Initialized) {\r
	186	return RETURN_SUCCESS;\r
	187	}\r
	188	\r
	189	//\r
	190	// Configure baud rate\r
	191	//\r
	192	Divisor = 115200 / PcdGet32 (PcdSerialBaudRate);\r
	193	SerialPortWriteRegister (R_UART_LCR, B_UART_LCR_DLAB);\r
	194	SerialPortWriteRegister (R_UART_BAUD_HIGH, (UINT8) (Divisor >> 8));\r
	195	SerialPortWriteRegister (R_UART_BAUD_LOW, (UINT8) (Divisor & 0xff));\r
	196	\r
	197	//\r
	198	// Clear DLAB and configure Data Bits, Parity, and Stop Bits.\r
	199	// Strip reserved bits from PcdSerialLineControl\r
	200	//\r
	201	SerialPortWriteRegister (R_UART_LCR, (UINT8)(PcdGet8 (PcdSerialLineControl) & 0x3F));\r
	202	\r
	203	//\r
	204	// Enable and reset FIFOs\r
	205	// Strip reserved bits from PcdSerialFifoControl\r
	206	//\r
	207	SerialPortWriteRegister (R_UART_FCR, (UINT8)(PcdGet8 (PcdSerialFifoControl) & 0x27));\r
	208	\r
	209	//\r
	210	// Put Modem Control Register(MCR) into its reset state of 0x00.\r
	211	// \r
	212	SerialPortWriteRegister (R_UART_MCR, 0x00);\r
	213	\r
	214	return RETURN_SUCCESS;\r
	215	}\r
	216	\r
	217	/**\r
	218	Write data from buffer to serial device. \r
	219	\r
	220	Writes NumberOfBytes data bytes from Buffer to the serial device. \r
	221	The number of bytes actually written to the serial device is returned.\r
	222	If the return value is less than NumberOfBytes, then the write operation failed.\r
	223	\r
	224	If Buffer is NULL, then ASSERT(). \r
	225	\r
	226	If NumberOfBytes is zero, then return 0.\r
	227	\r
	228	@param Buffer Pointer to the data buffer to be written.\r
	229	@param NumberOfBytes Number of bytes to written to the serial device.\r
	230	\r
	231	@retval 0 NumberOfBytes is 0.\r
	232	@retval >0 The number of bytes written to the serial device. \r
	233	If this value is less than NumberOfBytes, then the read operation failed.\r
	234	\r
	235	**/\r
	236	UINTN\r
	237	EFIAPI\r
	238	SerialPortWrite (\r
	239	IN UINT8 *Buffer,\r
	240	IN UINTN NumberOfBytes\r
	241	)\r
	242	{\r
	243	UINTN Result;\r
	244	UINTN Index;\r
	245	UINTN FifoSize;\r
	246	\r
	247	if (Buffer == NULL) {\r
	248	return 0;\r
	249	}\r
	250	\r
	251	if (NumberOfBytes == 0) {\r
	252	//\r
	253	// Flush the hardware\r
	254	//\r
	255	\r
	256	//\r
	257	// Wait for both the transmit FIFO and shift register empty.\r
	258	//\r
	259	while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);\r
	260	\r
	261	//\r
	262	// Wait for the hardware flow control signal\r
	263	//\r
	264	while (!SerialPortWritable ());\r
	265	return 0;\r
	266	}\r
	267	\r
	268	//\r
	269	// Compute the maximum size of the Tx FIFO\r
	270	//\r
	271	FifoSize = 1;\r
	272	if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFOE) != 0) {\r
	273	if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFO64) == 0) {\r
	274	FifoSize = 16;\r
	275	} else {\r
	276	FifoSize = 64;\r
	277	}\r
	278	}\r
	279	\r
	280	Result = NumberOfBytes;\r
	281	while (NumberOfBytes != 0) {\r
	282	//\r
	283	// Wait for the serial port to be ready, to make sure both the transmit FIFO\r
	284	// and shift register empty.\r
	285	//\r
	286	while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);\r
	287	\r
	288	//\r
	289	// Fill then entire Tx FIFO\r
	290	//\r
	291	for (Index = 0; Index < FifoSize && NumberOfBytes != 0; Index++, NumberOfBytes--, Buffer++) {\r
	292	//\r
	293	// Wait for the hardware flow control signal\r
	294	//\r
	295	while (!SerialPortWritable ());\r
	296	\r
	297	//\r
	298	// Write byte to the transmit buffer.\r
	299	//\r
	300	SerialPortWriteRegister (R_UART_TXBUF, *Buffer);\r
	301	}\r
	302	}\r
	303	return Result;\r
	304	}\r
	305	\r
	306	/**\r
	307	Reads data from a serial device into a buffer.\r
	308	\r
	309	@param Buffer Pointer to the data buffer to store the data read from the serial device.\r
	310	@param NumberOfBytes Number of bytes to read from the serial device.\r
	311	\r
	312	@retval 0 NumberOfBytes is 0.\r
	313	@retval >0 The number of bytes read from the serial device. \r
	314	If this value is less than NumberOfBytes, then the read operation failed.\r
	315	\r
	316	**/\r
	317	UINTN\r
	318	EFIAPI\r
	319	SerialPortRead (\r
	320	OUT UINT8 *Buffer,\r
	321	IN UINTN NumberOfBytes\r
	322	)\r
	323	{\r
	324	UINTN Result;\r
	325	UINT8 Mcr;\r
	326	\r
	327	if (NULL == Buffer) {\r
	328	return 0;\r
	329	}\r
	330	\r
	331	Mcr = (UINT8)(SerialPortReadRegister (R_UART_MCR) & ~B_UART_MCR_RTS);\r
	332	\r
	333	for (Result = 0; NumberOfBytes-- != 0; Result++, Buffer++) {\r
	334	//\r
	335	// Wait for the serial port to have some data.\r
	336	//\r
	337	while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) == 0) {\r
	338	if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
	339	//\r
	340	// Set RTS to let the peer send some data\r
	341	//\r
	342	SerialPortWriteRegister (R_UART_MCR, (UINT8)(Mcr \| B_UART_MCR_RTS));\r
	343	}\r
	344	}\r
	345	if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
	346	//\r
	347	// Clear RTS to prevent peer from sending data\r
	348	//\r
	349	SerialPortWriteRegister (R_UART_MCR, Mcr);\r
	350	}\r
	351	\r
	352	//\r
	353	// Read byte from the receive buffer.\r
	354	//\r
	355	*Buffer = SerialPortReadRegister (R_UART_RXBUF);\r
	356	}\r
	357	\r
	358	return Result;\r
	359	}\r
	360	\r
	361	/**\r
	362	Polls a serial device to see if there is any data waiting to be read.\r
	363	\r
	364	Polls aserial device to see if there is any data waiting to be read.\r
	365	If there is data waiting to be read from the serial device, then TRUE is returned.\r
	366	If there is no data waiting to be read from the serial device, then FALSE is returned.\r
	367	\r
	368	@retval TRUE Data is waiting to be read from the serial device.\r
	369	@retval FALSE There is no data waiting to be read from the serial device.\r
	370	\r
	371	**/\r
	372	BOOLEAN\r
	373	EFIAPI\r
	374	SerialPortPoll (\r
	375	VOID\r
	376	)\r
	377	{\r
	378	//\r
	379	// Read the serial port status\r
	380	//\r
	381	if ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) != 0) {\r
	382	if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
	383	//\r
	384	// Clear RTS to prevent peer from sending data\r
	385	//\r
	386	SerialPortWriteRegister (R_UART_MCR, (UINT8)(SerialPortReadRegister (R_UART_MCR) & ~B_UART_MCR_RTS));\r
	387	}\r
	388	return TRUE;\r
	389	} \r
	390	\r
	391	if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {\r
	392	//\r
	393	// Set RTS to let the peer send some data\r
	394	//\r
	395	SerialPortWriteRegister (R_UART_MCR, (UINT8)(SerialPortReadRegister (R_UART_MCR) \| B_UART_MCR_RTS));\r
	396	}\r
	397	\r
	398	return FALSE;\r
	399	}\r