MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c

   1 /** @file
   2   I/O Library. This file has compiler specifics for GCC as there is no
   3   ANSI C standard for doing IO.
   4
   5   GCC - uses EFIAPI assembler. __asm__ calls GAS. __volatile__ makes sure the
   6   compiler puts the assembler in this exact location. The complex GNUC
   7   operations are not optimzed. It would be possible to also write these
   8   with EFIAPI assembler.
   9
  10   We don't advocate putting compiler specifics in libraries or drivers but there
  11   is no other way to make this work.
  12
  13   Copyright (c) 2006 - 2008, Intel Corporation<BR>
  14   All rights reserved. This program and the accompanying materials
  15   are licensed and made available under the terms and conditions of the BSD License
  16   which accompanies this distribution.  The full text of the license may be found at
  17   http://opensource.org/licenses/bsd-license.php
  18
  19   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  20   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  21
  22 **/
  23
  24
  25 #include "BaseIoLibIntrinsicInternal.h"
  26
  27 /**
  28   Reads an 8-bit I/O port.
  29
  30   Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  31   This function must guarantee that all I/O read and write operations are
  32   serialized.
  33
  34   If 8-bit I/O port operations are not supported, then ASSERT().
  35
  36   @param  Port  The I/O port to read.
  37
  38   @return The value read.
  39
  40 **/
  41 __inline__
  42 UINT8
  43 EFIAPI
  44 IoRead8 (
  45   IN      UINTN                     Port
  46   )
  47 {
  48   UINT8   Data;
  49
  50   __asm__ __volatile__ ("inb %w1,%b0" : "=a" (Data) : "d" ((UINT16)Port));
  51   return Data;
  52 }
  53
  54 /**
  55   Writes an 8-bit I/O port.
  56
  57   Writes the 8-bit I/O port specified by Port with the value specified by Value
  58   and returns Value. This function must guarantee that all I/O read and write
  59   operations are serialized.
  60
  61   If 8-bit I/O port operations are not supported, then ASSERT().
  62
  63   @param  Port  The I/O port to write.
  64   @param  Value The value to write to the I/O port.
  65
  66   @return The value written the I/O port.
  67
  68 **/
  69 __inline__
  70 UINT8
  71 EFIAPI
  72 IoWrite8 (
  73   IN      UINTN                     Port,
  74   IN      UINT8                     Value
  75   )
  76 {
  77   __asm__ __volatile__ ("outb %b0,%w1" : : "a" (Value), "d" ((UINT16)Port));
  78   return Value;;
  79 }
  80
  81 /**
  82   Reads a 16-bit I/O port.
  83
  84   Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
  85   This function must guarantee that all I/O read and write operations are
  86   serialized.
  87
  88   If 16-bit I/O port operations are not supported, then ASSERT().
  89   If Port is not aligned on a 16-bit boundary, then ASSERT().
  90
  91   @param  Port  The I/O port to read.
  92
  93   @return The value read.
  94
  95 **/
  96 __inline__
  97 UINT16
  98 EFIAPI
  99 IoRead16 (
 100   IN      UINTN                     Port
 101   )
 102 {
 103   UINT16   Data;
 104
 105   ASSERT ((Port & 1) == 0);
 106   __asm__ __volatile__ ("inw %w1,%w0" : "=a" (Data) : "d" ((UINT16)Port));
 107   return Data;
 108 }
 109
 110 /**
 111   Writes a 16-bit I/O port.
 112
 113   Writes the 16-bit I/O port specified by Port with the value specified by Value
 114   and returns Value. This function must guarantee that all I/O read and write
 115   operations are serialized.
 116
 117   If 16-bit I/O port operations are not supported, then ASSERT().
 118   If Port is not aligned on a 16-bit boundary, then ASSERT().
 119
 120   @param  Port  The I/O port to write.
 121   @param  Value The value to write to the I/O port.
 122
 123   @return The value written the I/O port.
 124
 125 **/
 126 __inline__
 127 UINT16
 128 EFIAPI
 129 IoWrite16 (
 130   IN      UINTN                     Port,
 131   IN      UINT16                    Value
 132   )
 133 {
 134   ASSERT ((Port & 1) == 0);
 135   __asm__ __volatile__ ("outw %w0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 136   return Value;;
 137 }
 138
 139 /**
 140   Reads a 32-bit I/O port.
 141
 142   Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
 143   This function must guarantee that all I/O read and write operations are
 144   serialized.
 145
 146   If 32-bit I/O port operations are not supported, then ASSERT().
 147   If Port is not aligned on a 32-bit boundary, then ASSERT().
 148
 149   @param  Port  The I/O port to read.
 150
 151   @return The value read.
 152
 153 **/
 154 __inline__
 155 UINT32
 156 EFIAPI
 157 IoRead32 (
 158   IN      UINTN                     Port
 159   )
 160 {
 161   UINT32   Data;
 162
 163   ASSERT ((Port & 3) == 0);
 164   __asm__ __volatile__ ("inl %w1,%0" : "=a" (Data) : "d" ((UINT16)Port));
 165   return Data;
 166 }
 167
 168 /**
 169   Writes a 32-bit I/O port.
 170
 171   Writes the 32-bit I/O port specified by Port with the value specified by Value
 172   and returns Value. This function must guarantee that all I/O read and write
 173   operations are serialized.
 174
 175   If 32-bit I/O port operations are not supported, then ASSERT().
 176   If Port is not aligned on a 32-bit boundary, then ASSERT().
 177
 178   @param  Port  The I/O port to write.
 179   @param  Value The value to write to the I/O port.
 180
 181   @return The value written the I/O port.
 182
 183 **/
 184 __inline__
 185 UINT32
 186 EFIAPI
 187 IoWrite32 (
 188   IN      UINTN                     Port,
 189   IN      UINT32                    Value
 190   )
 191 {
 192   ASSERT ((Port & 3) == 0);
 193   __asm__ __volatile__ ("outl %0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 194   return Value;
 195 }
 196