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 - 2018, Intel Corporation. All rights reserved.<BR>
  14   SPDX-License-Identifier: BSD-2-Clause-Patent
  15
  16 **/
  17
  18
  19 #include "BaseIoLibIntrinsicInternal.h"
  20
  21 /**
  22   Reads an 8-bit I/O port.
  23
  24   Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  25   This function must guarantee that all I/O read and write operations are
  26   serialized.
  27
  28   If 8-bit I/O port operations are not supported, then ASSERT().
  29
  30   @param  Port  The I/O port to read.
  31
  32   @return The value read.
  33
  34 **/
  35 __inline__
  36 UINT8
  37 EFIAPI
  38 IoRead8 (
  39   IN      UINTN                     Port
  40   )
  41 {
  42   UINT8   Data;
  43
  44   __asm__ __volatile__ ("inb %w1,%b0" : "=a" (Data) : "d" ((UINT16)Port));
  45   return Data;
  46 }
  47
  48 /**
  49   Writes an 8-bit I/O port.
  50
  51   Writes the 8-bit I/O port specified by Port with the value specified by Value
  52   and returns Value. This function must guarantee that all I/O read and write
  53   operations are serialized.
  54
  55   If 8-bit I/O port operations are not supported, then ASSERT().
  56
  57   @param  Port  The I/O port to write.
  58   @param  Value The value to write to the I/O port.
  59
  60   @return The value written the I/O port.
  61
  62 **/
  63 __inline__
  64 UINT8
  65 EFIAPI
  66 IoWrite8 (
  67   IN      UINTN                     Port,
  68   IN      UINT8                     Value
  69   )
  70 {
  71   __asm__ __volatile__ ("outb %b0,%w1" : : "a" (Value), "d" ((UINT16)Port));
  72   return Value;;
  73 }
  74
  75 /**
  76   Reads a 16-bit I/O port.
  77
  78   Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
  79   This function must guarantee that all I/O read and write operations are
  80   serialized.
  81
  82   If 16-bit I/O port operations are not supported, then ASSERT().
  83   If Port is not aligned on a 16-bit boundary, then ASSERT().
  84
  85   @param  Port  The I/O port to read.
  86
  87   @return The value read.
  88
  89 **/
  90 __inline__
  91 UINT16
  92 EFIAPI
  93 IoRead16 (
  94   IN      UINTN                     Port
  95   )
  96 {
  97   UINT16   Data;
  98
  99   ASSERT ((Port & 1) == 0);
 100   __asm__ __volatile__ ("inw %w1,%w0" : "=a" (Data) : "d" ((UINT16)Port));
 101   return Data;
 102 }
 103
 104 /**
 105   Writes a 16-bit I/O port.
 106
 107   Writes the 16-bit I/O port specified by Port with the value specified by Value
 108   and returns Value. This function must guarantee that all I/O read and write
 109   operations are 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 write.
 115   @param  Value The value to write to the I/O port.
 116
 117   @return The value written the I/O port.
 118
 119 **/
 120 __inline__
 121 UINT16
 122 EFIAPI
 123 IoWrite16 (
 124   IN      UINTN                     Port,
 125   IN      UINT16                    Value
 126   )
 127 {
 128   ASSERT ((Port & 1) == 0);
 129   __asm__ __volatile__ ("outw %w0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 130   return Value;;
 131 }
 132
 133 /**
 134   Reads a 32-bit I/O port.
 135
 136   Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
 137   This function must guarantee that all I/O read and write operations are
 138   serialized.
 139
 140   If 32-bit I/O port operations are not supported, then ASSERT().
 141   If Port is not aligned on a 32-bit boundary, then ASSERT().
 142
 143   @param  Port  The I/O port to read.
 144
 145   @return The value read.
 146
 147 **/
 148 __inline__
 149 UINT32
 150 EFIAPI
 151 IoRead32 (
 152   IN      UINTN                     Port
 153   )
 154 {
 155   UINT32   Data;
 156
 157   ASSERT ((Port & 3) == 0);
 158   __asm__ __volatile__ ("inl %w1,%0" : "=a" (Data) : "d" ((UINT16)Port));
 159   return Data;
 160 }
 161
 162 /**
 163   Writes a 32-bit I/O port.
 164
 165   Writes the 32-bit I/O port specified by Port with the value specified by Value
 166   and returns Value. This function must guarantee that all I/O read and write
 167   operations are serialized.
 168
 169   If 32-bit I/O port operations are not supported, then ASSERT().
 170   If Port is not aligned on a 32-bit boundary, then ASSERT().
 171
 172   @param  Port  The I/O port to write.
 173   @param  Value The value to write to the I/O port.
 174
 175   @return The value written the I/O port.
 176
 177 **/
 178 __inline__
 179 UINT32
 180 EFIAPI
 181 IoWrite32 (
 182   IN      UINTN                     Port,
 183   IN      UINT32                    Value
 184   )
 185 {
 186   ASSERT ((Port & 3) == 0);
 187   __asm__ __volatile__ ("outl %0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 188   return Value;
 189 }
 190