MdePkg/Library/BaseIoLibIntrinsic/IoLibMsc.c

   1 /** @file
   2   I/O Library. This file has compiler specifics for Microsft C as there is no
   3   ANSI C standard for doing IO.
   4
   5   MSC - uses intrinsic functions and the optimize will remove the function call
   6   overhead.
   7
   8   We don't advocate putting compiler specifics in libraries or drivers but there
   9   is no other way to make this work.
  10
  11   Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
  12   SPDX-License-Identifier: BSD-2-Clause-Patent
  13
  14 **/
  15
  16
  17
  18 #include "BaseIoLibIntrinsicInternal.h"
  19
  20 //
  21 // Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  22 //
  23
  24 int            _inp (unsigned short port);
  25 unsigned short _inpw (unsigned short port);
  26 unsigned long  _inpd (unsigned short port);
  27 int            _outp (unsigned short port, int databyte );
  28 unsigned short _outpw (unsigned short port, unsigned short dataword );
  29 unsigned long  _outpd (unsigned short port, unsigned long dataword );
  30 void          _ReadWriteBarrier (void);
  31
  32 #pragma intrinsic(_inp)
  33 #pragma intrinsic(_inpw)
  34 #pragma intrinsic(_inpd)
  35 #pragma intrinsic(_outp)
  36 #pragma intrinsic(_outpw)
  37 #pragma intrinsic(_outpd)
  38 #pragma intrinsic(_ReadWriteBarrier)
  39
  40 //
  41 // _ReadWriteBarrier() forces memory reads and writes to complete at the point
  42 // in the call. This is only a hint to the compiler and does emit code.
  43 // In past versions of the compiler, _ReadWriteBarrier was enforced only
  44 // locally and did not affect functions up the call tree. In Visual C++
  45 // 2005, _ReadWriteBarrier is enforced all the way up the call tree.
  46 //
  47
  48 /**
  49   Reads an 8-bit I/O port.
  50
  51   Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  52   This function must guarantee that all I/O read and write operations are
  53   serialized.
  54
  55   If 8-bit I/O port operations are not supported, then ASSERT().
  56
  57   @param  Port  The I/O port to read.
  58
  59   @return The value read.
  60
  61 **/
  62 UINT8
  63 EFIAPI
  64 IoRead8 (
  65   IN      UINTN                     Port
  66   )
  67 {
  68   UINT8                             Value;
  69
  70   _ReadWriteBarrier ();
  71   Value = (UINT8)_inp ((UINT16)Port);
  72   _ReadWriteBarrier ();
  73   return Value;
  74 }
  75
  76 /**
  77   Writes an 8-bit I/O port.
  78
  79   Writes the 8-bit I/O port specified by Port with the value specified by Value
  80   and returns Value. This function must guarantee that all I/O read and write
  81   operations are serialized.
  82
  83   If 8-bit I/O port operations are not supported, then ASSERT().
  84
  85   @param  Port  The I/O port to write.
  86   @param  Value The value to write to the I/O port.
  87
  88   @return The value written to the I/O port.
  89
  90 **/
  91 UINT8
  92 EFIAPI
  93 IoWrite8 (
  94   IN      UINTN                     Port,
  95   IN      UINT8                     Value
  96   )
  97 {
  98   _ReadWriteBarrier ();
  99   (UINT8)_outp ((UINT16)Port, Value);
 100   _ReadWriteBarrier ();
 101   return Value;
 102 }
 103
 104 /**
 105   Reads a 16-bit I/O port.
 106
 107   Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
 108   This function must guarantee that all I/O read and write operations are
 109   serialized.
 110
 111   If 16-bit I/O port operations are not supported, then ASSERT().
 112   If Port is not aligned on a 16-bit boundary, then ASSERT().
 113
 114   @param  Port  The I/O port to read.
 115
 116   @return The value read.
 117
 118 **/
 119 UINT16
 120 EFIAPI
 121 IoRead16 (
 122   IN      UINTN                     Port
 123   )
 124 {
 125   UINT16                            Value;
 126
 127   ASSERT ((Port & 1) == 0);
 128   _ReadWriteBarrier ();
 129   Value = _inpw ((UINT16)Port);
 130   _ReadWriteBarrier ();
 131   return Value;
 132 }
 133
 134 /**
 135   Writes a 16-bit I/O port.
 136
 137   Writes the 16-bit I/O port specified by Port with the value specified by Value
 138   and returns Value. This function must guarantee that all I/O read and write
 139   operations are serialized.
 140
 141   If 16-bit I/O port operations are not supported, then ASSERT().
 142   If Port is not aligned on a 16-bit boundary, then ASSERT().
 143
 144   @param  Port  The I/O port to write.
 145   @param  Value The value to write to the I/O port.
 146
 147   @return The value written to the I/O port.
 148
 149 **/
 150 UINT16
 151 EFIAPI
 152 IoWrite16 (
 153   IN      UINTN                     Port,
 154   IN      UINT16                    Value
 155   )
 156 {
 157   ASSERT ((Port & 1) == 0);
 158   _ReadWriteBarrier ();
 159   _outpw ((UINT16)Port, Value);
 160   _ReadWriteBarrier ();
 161   return Value;
 162 }
 163
 164 /**
 165   Reads a 32-bit I/O port.
 166
 167   Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
 168   This function must guarantee that all I/O read and write operations are
 169   serialized.
 170
 171   If 32-bit I/O port operations are not supported, then ASSERT().
 172   If Port is not aligned on a 32-bit boundary, then ASSERT().
 173
 174   @param  Port  The I/O port to read.
 175
 176   @return The value read.
 177
 178 **/
 179 UINT32
 180 EFIAPI
 181 IoRead32 (
 182   IN      UINTN                     Port
 183   )
 184 {
 185   UINT32                            Value;
 186
 187   ASSERT ((Port & 3) == 0);
 188   _ReadWriteBarrier ();
 189   Value = _inpd ((UINT16)Port);
 190   _ReadWriteBarrier ();
 191   return Value;
 192 }
 193
 194 /**
 195   Writes a 32-bit I/O port.
 196
 197   Writes the 32-bit I/O port specified by Port with the value specified by Value
 198   and returns Value. This function must guarantee that all I/O read and write
 199   operations are serialized.
 200
 201   If 32-bit I/O port operations are not supported, then ASSERT().
 202   If Port is not aligned on a 32-bit boundary, then ASSERT().
 203
 204   @param  Port  The I/O port to write.
 205   @param  Value The value to write to the I/O port.
 206
 207   @return The value written to the I/O port.
 208
 209 **/
 210 UINT32
 211 EFIAPI
 212 IoWrite32 (
 213   IN      UINTN                     Port,
 214   IN      UINT32                    Value
 215   )
 216 {
 217   ASSERT ((Port & 3) == 0);
 218   _ReadWriteBarrier ();
 219   _outpd ((UINT16)Port, Value);
 220   _ReadWriteBarrier ();
 221   return Value;
 222 }