audk/MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c

185 lines
4.6 KiB
C

/** @file
I/O Library. This file has compiler specifics for GCC as there is no
ANSI C standard for doing IO.
GCC - uses EFIAPI assembler. __asm__ calls GAS. __volatile__ makes sure the
compiler puts the assembler in this exact location. The complex GNUC
operations are not optimzed. It would be possible to also write these
with EFIAPI assembler.
We don't advocate putting compiler specifics in libraries or drivers but there
is no other way to make this work.
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "BaseIoLibIntrinsicInternal.h"
/**
Reads an 8-bit I/O port.
Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
This function must guarantee that all I/O read and write operations are
serialized.
If 8-bit I/O port operations are not supported, then ASSERT().
@param Port The I/O port to read.
@return The value read.
**/
UINT8
EFIAPI
IoRead8 (
IN UINTN Port
)
{
UINT8 Data;
__asm__ __volatile__ ("inb %w1,%b0" : "=a" (Data) : "d" ((UINT16)Port));
return Data;
}
/**
Writes an 8-bit I/O port.
Writes the 8-bit I/O port specified by Port with the value specified by Value
and returns Value. This function must guarantee that all I/O read and write
operations are serialized.
If 8-bit I/O port operations are not supported, then ASSERT().
@param Port The I/O port to write.
@param Value The value to write to the I/O port.
@return The value written the I/O port.
**/
UINT8
EFIAPI
IoWrite8 (
IN UINTN Port,
IN UINT8 Value
)
{
__asm__ __volatile__ ("outb %b0,%w1" : : "a" (Value), "d" ((UINT16)Port));
return Value;;
}
/**
Reads a 16-bit I/O port.
Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
This function must guarantee that all I/O read and write operations are
serialized.
If 16-bit I/O port operations are not supported, then ASSERT().
If Port is not aligned on a 16-bit boundary, then ASSERT().
@param Port The I/O port to read.
@return The value read.
**/
UINT16
EFIAPI
IoRead16 (
IN UINTN Port
)
{
UINT16 Data;
ASSERT ((Port & 1) == 0);
__asm__ __volatile__ ("inw %w1,%w0" : "=a" (Data) : "d" ((UINT16)Port));
return Data;
}
/**
Writes a 16-bit I/O port.
Writes the 16-bit I/O port specified by Port with the value specified by Value
and returns Value. This function must guarantee that all I/O read and write
operations are serialized.
If 16-bit I/O port operations are not supported, then ASSERT().
If Port is not aligned on a 16-bit boundary, then ASSERT().
@param Port The I/O port to write.
@param Value The value to write to the I/O port.
@return The value written the I/O port.
**/
UINT16
EFIAPI
IoWrite16 (
IN UINTN Port,
IN UINT16 Value
)
{
ASSERT ((Port & 1) == 0);
__asm__ __volatile__ ("outw %w0,%w1" : : "a" (Value), "d" ((UINT16)Port));
return Value;;
}
/**
Reads a 32-bit I/O port.
Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
This function must guarantee that all I/O read and write operations are
serialized.
If 32-bit I/O port operations are not supported, then ASSERT().
If Port is not aligned on a 32-bit boundary, then ASSERT().
@param Port The I/O port to read.
@return The value read.
**/
UINT32
EFIAPI
IoRead32 (
IN UINTN Port
)
{
UINT32 Data;
ASSERT ((Port & 3) == 0);
__asm__ __volatile__ ("inl %w1,%0" : "=a" (Data) : "d" ((UINT16)Port));
return Data;
}
/**
Writes a 32-bit I/O port.
Writes the 32-bit I/O port specified by Port with the value specified by Value
and returns Value. This function must guarantee that all I/O read and write
operations are serialized.
If 32-bit I/O port operations are not supported, then ASSERT().
If Port is not aligned on a 32-bit boundary, then ASSERT().
@param Port The I/O port to write.
@param Value The value to write to the I/O port.
@return The value written the I/O port.
**/
UINT32
EFIAPI
IoWrite32 (
IN UINTN Port,
IN UINT32 Value
)
{
ASSERT ((Port & 3) == 0);
__asm__ __volatile__ ("outl %0,%w1" : : "a" (Value), "d" ((UINT16)Port));
return Value;
}