ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c

   1 /** @file
   2   Serial I/O Port library functions with no library constructor/destructor
   3
   4
   5   Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
   6
   7   This program and the accompanying materials
   8   are licensed and made available under the terms and conditions of the BSD License
   9   which accompanies this distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #include <Include/Uefi.h>
  18
  19 #include <Library/IoLib.h>
  20
  21 #include <Drivers/PL011Uart.h>
  22
  23 /*
  24
  25   Programmed hardware of Serial port.
  26
  27   @return    Always return EFI_UNSUPPORTED.
  28
  29 **/
  30 RETURN_STATUS
  31 EFIAPI
  32 PL011UartInitialize (
  33   IN  UINTN       UartBase,
  34   IN  UINTN       BaudRate,
  35   IN  UINTN       LineControl
  36   )
  37 {
  38         if (BaudRate == 115200) {
  39                 // Initialize baud rate generator
  40                 MmioWrite32 (UartBase + UARTIBRD, UART_115200_IDIV);
  41                 MmioWrite32 (UartBase + UARTFBRD, UART_115200_FDIV);
  42         } else if (BaudRate == 38400) {
  43                 // Initialize baud rate generator
  44                 MmioWrite32 (UartBase + UARTIBRD, UART_38400_IDIV);
  45                 MmioWrite32 (UartBase + UARTFBRD, UART_38400_FDIV);
  46         } else if (BaudRate == 19200) {
  47                 // Initialize baud rate generator
  48                 MmioWrite32 (UartBase + UARTIBRD, UART_19200_IDIV);
  49                 MmioWrite32 (UartBase + UARTFBRD, UART_19200_FDIV);
  50         } else {
  51                 return EFI_INVALID_PARAMETER;
  52         }
  53
  54   // No parity, 1 stop, no fifo, 8 data bits
  55   MmioWrite32 (UartBase + UARTLCR_H, LineControl);
  56
  57   // Clear any pending errors
  58   MmioWrite32 (UartBase + UARTECR, 0);
  59
  60   // Enable tx, rx, and uart overall
  61   MmioWrite32 (UartBase + UARTCR, PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN);
  62
  63   return EFI_SUCCESS;
  64 }
  65
  66 /**
  67   Write data to serial device.
  68
  69   @param  Buffer           Point of data buffer which need to be written.
  70   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
  71
  72   @retval 0                Write data failed.
  73   @retval !0               Actual number of bytes written to serial device.
  74
  75 **/
  76 UINTN
  77 EFIAPI
  78 PL011UartWrite (
  79   IN  UINTN    UartBase,
  80   IN UINT8     *Buffer,
  81   IN UINTN     NumberOfBytes
  82   )
  83 {
  84         UINTN  Count;
  85
  86         for (Count = 0; Count < NumberOfBytes; Count++, Buffer++) {
  87                 while ((MmioRead32 (UartBase + UARTFR) & UART_TX_EMPTY_FLAG_MASK) == 0);
  88                 MmioWrite8 (UartBase + UARTDR, *Buffer);
  89         }
  90
  91         return NumberOfBytes;
  92 }
  93
  94 /**
  95   Read data from serial device and save the data in buffer.
  96
  97   @param  Buffer           Point of data buffer which need to be written.
  98   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
  99
 100   @retval 0                Read data failed.
 101   @retval !0               Actual number of bytes read from serial device.
 102
 103 **/
 104 UINTN
 105 EFIAPI
 106 PL011UartRead (
 107   IN  UINTN     UartBase,
 108   OUT UINT8     *Buffer,
 109   IN  UINTN     NumberOfBytes
 110   )
 111 {
 112   UINTN   Count;
 113
 114         for (Count = 0; Count < NumberOfBytes; Count++, Buffer++) {
 115                 while ((MmioRead32 (UartBase + UARTFR) & UART_RX_EMPTY_FLAG_MASK) != 0);
 116                 *Buffer = MmioRead8 (UartBase + UARTDR);
 117         }
 118
 119         return NumberOfBytes;
 120 }
 121
 122 /**
 123   Check to see if any data is available to be read from the debug device.
 124
 125   @retval EFI_SUCCESS       At least one byte of data is available to be read
 126   @retval EFI_NOT_READY     No data is available to be read
 127   @retval EFI_DEVICE_ERROR  The serial device is not functioning properly
 128
 129 **/
 130 BOOLEAN
 131 EFIAPI
 132 PL011UartPoll (
 133   IN  UINTN     UartBase
 134   )
 135 {
 136   return ((MmioRead32 (UartBase + UARTFR) & UART_RX_EMPTY_FLAG_MASK) == 0);
 137 }