PcAtChipsetPkg/Library/SerialIoLib/SerialPortLib.c

   1 /** @file
   2   UART Serial Port library instance with empty functions.
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include <Base.h>
  16
  17 #include <Library/SerialPortLib.h>
  18 #include <Library/IoLib.h>
  19
  20 //---------------------------------------------
  21 // UART Register Offsets
  22 //---------------------------------------------
  23 #define BAUD_LOW_OFFSET         0x00
  24 #define BAUD_HIGH_OFFSET        0x01
  25 #define IER_OFFSET              0x01
  26 #define LCR_SHADOW_OFFSET       0x01
  27 #define FCR_SHADOW_OFFSET       0x02
  28 #define IR_CONTROL_OFFSET       0x02
  29 #define FCR_OFFSET              0x02
  30 #define EIR_OFFSET              0x02
  31 #define BSR_OFFSET              0x03
  32 #define LCR_OFFSET              0x03
  33 #define MCR_OFFSET              0x04
  34 #define LSR_OFFSET              0x05
  35 #define MSR_OFFSET              0x06
  36
  37 //---------------------------------------------
  38 // UART Register Bit Defines
  39 //---------------------------------------------
  40 #define LSR_TXRDY               0x20
  41 #define LSR_RXDA                0x01
  42 #define DLAB                    0x01
  43
  44 //---------------------------------------------
  45 // UART Settings
  46 //---------------------------------------------
  47 UINT16  gUartBase = 0x3F8;
  48 UINTN   gBps      = 115200;
  49 UINT8   gData     = 8;
  50 UINT8   gStop     = 1;
  51 UINT8   gParity   = 0;
  52 UINT8   gBreakSet = 0;
  53
  54 /**
  55   Initialize the serial device hardware.
  56
  57   If no initialization is required, then return RETURN_SUCCESS.
  58   If the serial device was successfuly initialized, then return RETURN_SUCCESS.
  59   If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.
  60
  61   @retval RETURN_SUCCESS        The serial device was initialized.
  62   @retval RETURN_DEVICE_ERROR   The serail device could not be initialized.
  63
  64 **/
  65 RETURN_STATUS
  66 EFIAPI
  67 SerialPortInitialize (
  68   VOID
  69   )
  70 {
  71   UINTN  Divisor;
  72   UINT8  OutputData;
  73   UINT8  Data;
  74
  75   //
  76   // Map 5..8 to 0..3
  77   //
  78   Data = (UINT8) (gData - (UINT8) 5);
  79
  80   //
  81   // Calculate divisor for baud generator
  82   //
  83   Divisor = 115200 / gBps;
  84
  85   //
  86   // Set communications format
  87   //
  88   OutputData = (UINT8) ((DLAB << 7) | (gBreakSet << 6) | (gParity << 3) | (gStop << 2) | Data);
  89   IoWrite8 ((UINTN) (gUartBase + LCR_OFFSET), OutputData);
  90
  91   //
  92   // Configure baud rate
  93   //
  94   IoWrite8 ((UINTN) (gUartBase + BAUD_HIGH_OFFSET), (UINT8) (Divisor >> 8));
  95   IoWrite8 ((UINTN) (gUartBase + BAUD_LOW_OFFSET), (UINT8) (Divisor & 0xff));
  96
  97   //
  98   // Switch back to bank 0
  99   //
 100   OutputData = (UINT8) ((~DLAB << 7) | (gBreakSet << 6) | (gParity << 3) | (gStop << 2) | Data);
 101   IoWrite8 ((UINTN) (gUartBase + LCR_OFFSET), OutputData);
 102
 103   return RETURN_SUCCESS;
 104 }
 105
 106 /**
 107   Write data from buffer to serial device.
 108
 109   Writes NumberOfBytes data bytes from Buffer to the serial device.
 110   The number of bytes actually written to the serial device is returned.
 111   If the return value is less than NumberOfBytes, then the write operation failed.
 112
 113   If Buffer is NULL, then ASSERT().
 114
 115   If NumberOfBytes is zero, then return 0.
 116
 117   @param  Buffer           Pointer to the data buffer to be written.
 118   @param  NumberOfBytes    Number of bytes to written to the serial device.
 119
 120   @retval 0                NumberOfBytes is 0.
 121   @retval >0               The number of bytes written to the serial device.
 122                            If this value is less than NumberOfBytes, then the read operation failed.
 123
 124 **/
 125 UINTN
 126 EFIAPI
 127 SerialPortWrite (
 128   IN UINT8     *Buffer,
 129   IN UINTN     NumberOfBytes
 130 )
 131 {
 132   UINTN  Result;
 133   UINT8  Data;
 134
 135   if (Buffer == NULL) {
 136     return 0;
 137   }
 138
 139   Result = NumberOfBytes;
 140
 141   while (NumberOfBytes--) {
 142     //
 143     // Wait for the serail port to be ready.
 144     //
 145     do {
 146       Data = IoRead8 ((UINT16) gUartBase + LSR_OFFSET);
 147     } while ((Data & LSR_TXRDY) == 0);
 148     IoWrite8 ((UINT16) gUartBase, *Buffer++);
 149   }
 150
 151   return Result;
 152 }
 153
 154
 155 /**
 156   Reads data from a serial device into a buffer.
 157
 158   @param  Buffer           Pointer to the data buffer to store the data read from the serial device.
 159   @param  NumberOfBytes    Number of bytes to read from the serial device.
 160
 161   @retval 0                NumberOfBytes is 0.
 162   @retval >0               The number of bytes read from the serial device.
 163                            If this value is less than NumberOfBytes, then the read operation failed.
 164
 165 **/
 166 UINTN
 167 EFIAPI
 168 SerialPortRead (
 169   OUT UINT8     *Buffer,
 170   IN  UINTN     NumberOfBytes
 171 )
 172 {
 173   UINTN  Result;
 174   UINT8  Data;
 175
 176   if (NULL == Buffer) {
 177     return 0;
 178   }
 179
 180   Result = NumberOfBytes;
 181
 182   while (NumberOfBytes--) {
 183     //
 184     // Wait for the serail port to be ready.
 185     //
 186     do {
 187       Data = IoRead8 ((UINT16) gUartBase + LSR_OFFSET);
 188     } while ((Data & LSR_RXDA) == 0);
 189
 190     *Buffer++ = IoRead8 ((UINT16) gUartBase);
 191   }
 192
 193   return Result;
 194 }
 195
 196 /**
 197   Polls a serial device to see if there is any data waiting to be read.
 198
 199   Polls aserial device to see if there is any data waiting to be read.
 200   If there is data waiting to be read from the serial device, then TRUE is returned.
 201   If there is no data waiting to be read from the serial device, then FALSE is returned.
 202
 203   @retval TRUE             Data is waiting to be read from the serial device.
 204   @retval FALSE            There is no data waiting to be read from the serial device.
 205
 206 **/
 207 BOOLEAN
 208 EFIAPI
 209 SerialPortPoll (
 210   VOID
 211   )
 212 {
 213   UINT8  Data;
 214
 215   //
 216   // Read the serial port status.
 217   //
 218   Data = IoRead8 ((UINT16) gUartBase + LSR_OFFSET);
 219
 220   return (BOOLEAN) ((Data & LSR_RXDA) != 0);
 221 }
 222