ArmPlatformPkg/ArmVirtualizationPkg/Library/FdtPL011SerialPortLib/EarlyFdtPL011SerialPortLib.c

   1 /** @file
   2   Serial I/O Port library functions with base address discovered from FDT
   3
   4   Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
   5   Copyright (c) 2012 - 2013, ARM Ltd. All rights reserved.<BR>
   6   Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
   7
   8   This program and the accompanying materials
   9   are licensed and made available under the terms and conditions of the BSD License
  10   which accompanies this distribution.  The full text of the license may be found at
  11   http://opensource.org/licenses/bsd-license.php
  12
  13   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  14   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  15
  16 **/
  17
  18 #include <Base.h>
  19
  20 #include <Library/PcdLib.h>
  21 #include <Library/SerialPortLib.h>
  22 #include <Library/SerialPortExtLib.h>
  23 #include <libfdt.h>
  24
  25 #include <Drivers/PL011Uart.h>
  26
  27 RETURN_STATUS
  28 EFIAPI
  29 SerialPortInitialize (
  30   VOID
  31   )
  32 {
  33   //
  34   // This SerialPortInitialize() function is completely empty, for a number of
  35   // reasons:
  36   // - if we are executing from flash, it is hard to keep state (i.e., store the
  37   //   discovered base address in a global), and the most robust way to deal
  38   //   with this is to discover the base address at every Write ();
  39   // - calls to the Write() function in this module may be issued before this
  40   //   initialization function is called: this is not a problem when the base
  41   //   address of the UART is hardcoded, and only the baud rate may be wrong,
  42   //   but if we don't know the base address yet, we may be poking into memory
  43   //   that does not tolerate being poked into;
  44   // - SEC and PEI phases produce debug output only, so with debug disabled, no
  45   //   initialization (or device tree parsing) is performed at all.
  46   //
  47   // Note that this means that on *every* Write () call, the device tree will be
  48   // parsed and the UART re-initialized. However, this is a small price to pay
  49   // for having serial debug output on a UART with no fixed base address.
  50   //
  51   return RETURN_SUCCESS;
  52 }
  53
  54 STATIC
  55 UINT64
  56 SerialPortGetBaseAddress (
  57   VOID
  58   )
  59 {
  60   UINT64              BaudRate;
  61   UINT32              ReceiveFifoDepth;
  62   EFI_PARITY_TYPE     Parity;
  63   UINT8               DataBits;
  64   EFI_STOP_BITS_TYPE  StopBits;
  65   VOID                *DeviceTreeBase;
  66   INT32               Node, Prev;
  67   INT32               Len;
  68   CONST CHAR8         *Compatible;
  69   CONST CHAR8         *CompatibleItem;
  70   CONST UINT64        *RegProperty;
  71   UINTN               UartBase;
  72   RETURN_STATUS       Status;
  73
  74   DeviceTreeBase = (VOID *)(UINTN)FixedPcdGet64 (PcdDeviceTreeInitialBaseAddress);
  75
  76   if ((DeviceTreeBase == NULL) || (fdt_check_header (DeviceTreeBase) != 0)) {
  77     return 0;
  78   }
  79
  80   //
  81   // Enumerate all FDT nodes looking for a PL011 and capture its base address
  82   //
  83   for (Prev = 0;; Prev = Node) {
  84     Node = fdt_next_node (DeviceTreeBase, Prev, NULL);
  85     if (Node < 0) {
  86       break;
  87     }
  88
  89     Compatible = fdt_getprop (DeviceTreeBase, Node, "compatible", &Len);
  90     if (Compatible == NULL) {
  91       continue;
  92     }
  93
  94     //
  95     // Iterate over the NULL-separated items in the compatible string
  96     //
  97     for (CompatibleItem = Compatible; CompatibleItem < Compatible + Len;
  98       CompatibleItem += 1 + AsciiStrLen (CompatibleItem)) {
  99
 100       if (AsciiStrCmp (CompatibleItem, "arm,pl011") == 0) {
 101         RegProperty = fdt_getprop (DeviceTreeBase, Node, "reg", &Len);
 102         if (Len != 16) {
 103           return 0;
 104         }
 105         UartBase = (UINTN)fdt64_to_cpu (ReadUnaligned64 (RegProperty));
 106
 107         BaudRate = (UINTN)FixedPcdGet64 (PcdUartDefaultBaudRate);
 108         ReceiveFifoDepth = 0; // Use the default value for Fifo depth
 109         Parity = (EFI_PARITY_TYPE)FixedPcdGet8 (PcdUartDefaultParity);
 110         DataBits = FixedPcdGet8 (PcdUartDefaultDataBits);
 111         StopBits = (EFI_STOP_BITS_TYPE) FixedPcdGet8 (PcdUartDefaultStopBits);
 112
 113         Status = PL011UartInitializePort (
 114                    UartBase,
 115                    &BaudRate, &ReceiveFifoDepth, &Parity, &DataBits, &StopBits);
 116         if (!EFI_ERROR (Status)) {
 117           return UartBase;
 118         }
 119       }
 120     }
 121   }
 122   return 0;
 123 }
 124
 125 /**
 126   Write data to serial device.
 127
 128   @param  Buffer           Point of data buffer which need to be written.
 129   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
 130
 131   @retval 0                Write data failed.
 132   @retval !0               Actual number of bytes written to serial device.
 133
 134 **/
 135 UINTN
 136 EFIAPI
 137 SerialPortWrite (
 138   IN UINT8     *Buffer,
 139   IN UINTN     NumberOfBytes
 140   )
 141 {
 142   UINT64 SerialRegisterBase;
 143
 144   SerialRegisterBase = SerialPortGetBaseAddress ();
 145   if (SerialRegisterBase != 0) {
 146     return PL011UartWrite ((UINTN)SerialRegisterBase, Buffer, NumberOfBytes);
 147   }
 148   return 0;
 149 }
 150
 151 /**
 152   Read data from serial device and save the data in buffer.
 153
 154   @param  Buffer           Point of data buffer which need to be written.
 155   @param  NumberOfBytes    Size of Buffer[].
 156
 157   @retval 0                Read data failed.
 158   @retval !0               Actual number of bytes read from serial device.
 159
 160 **/
 161 UINTN
 162 EFIAPI
 163 SerialPortRead (
 164   OUT UINT8     *Buffer,
 165   IN  UINTN     NumberOfBytes
 166 )
 167 {
 168   return 0;
 169 }
 170
 171 /**
 172   Check to see if any data is available to be read from the debug device.
 173
 174   @retval TRUE       At least one byte of data is available to be read
 175   @retval FALSE      No data is available to be read
 176
 177 **/
 178 BOOLEAN
 179 EFIAPI
 180 SerialPortPoll (
 181   VOID
 182   )
 183 {
 184   return FALSE;
 185 }