300 lines
11 KiB
C
300 lines
11 KiB
C
/*****************************************************************************\
|
|
* cmos_lowlevel.c
|
|
* $Id$
|
|
*****************************************************************************
|
|
* Copyright (C) 2002-2005 The Regents of the University of California.
|
|
* Produced at the Lawrence Livermore National Laboratory.
|
|
* Written by David S. Peterson <dsp@llnl.gov> <dave_peterson@pobox.com>.
|
|
* UCRL-CODE-2003-012
|
|
* All rights reserved.
|
|
*
|
|
* This file is part of nvramtool, a utility for reading/writing coreboot
|
|
* parameters and displaying information from the coreboot table.
|
|
* For details, see http://coreboot.org/nvramtool.
|
|
*
|
|
* Please also read the file DISCLAIMER which is included in this software
|
|
* distribution.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License (as published by the
|
|
* Free Software Foundation) version 2, dated June 1991.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
|
|
* conditions of the GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
|
|
\*****************************************************************************/
|
|
|
|
#include <sys/io.h>
|
|
#include "common.h"
|
|
#include "cmos_lowlevel.h"
|
|
|
|
typedef struct
|
|
{ unsigned byte_index;
|
|
unsigned bit_offset;
|
|
}
|
|
cmos_bit_op_location_t;
|
|
|
|
static unsigned cmos_bit_op_strategy (unsigned bit, unsigned bits_left,
|
|
cmos_bit_op_location_t *where);
|
|
static unsigned char cmos_read_bits (const cmos_bit_op_location_t *where,
|
|
unsigned nr_bits);
|
|
static void cmos_write_bits (const cmos_bit_op_location_t *where,
|
|
unsigned nr_bits, unsigned char value);
|
|
static unsigned char get_bits (unsigned long long value, unsigned bit,
|
|
unsigned nr_bits);
|
|
static void put_bits (unsigned char value, unsigned bit, unsigned nr_bits,
|
|
unsigned long long *result);
|
|
|
|
/****************************************************************************
|
|
* get_bits
|
|
*
|
|
* Extract a value 'nr_bits' bits wide starting at bit position 'bit' from
|
|
* 'value' and return the result. It is assumed that 'nr_bits' is at most 8.
|
|
****************************************************************************/
|
|
static inline unsigned char get_bits (unsigned long long value, unsigned bit,
|
|
unsigned nr_bits)
|
|
{ return (value >> bit) & ((unsigned char) ((1 << nr_bits) - 1)); }
|
|
|
|
/****************************************************************************
|
|
* put_bits
|
|
*
|
|
* Extract the low order 'nr_bits' bits from 'value' and store them in the
|
|
* value pointed to by 'result' starting at bit position 'bit'. The bit
|
|
* positions in 'result' where the result is stored are assumed to be
|
|
* initially zero.
|
|
****************************************************************************/
|
|
static inline void put_bits (unsigned char value, unsigned bit,
|
|
unsigned nr_bits, unsigned long long *result)
|
|
{ *result += (value & ((unsigned char) ((1 << nr_bits) - 1))) << bit; }
|
|
|
|
/****************************************************************************
|
|
* cmos_read
|
|
*
|
|
* Read value from nonvolatile RAM at position given by 'bit' and 'length'
|
|
* and return this value. The I/O privilege level of the currently executing
|
|
* process must be set appropriately.
|
|
****************************************************************************/
|
|
unsigned long long cmos_read (unsigned bit, unsigned length)
|
|
{ cmos_bit_op_location_t where;
|
|
unsigned next_bit, bits_left, nr_bits;
|
|
unsigned long long result;
|
|
unsigned char value;
|
|
|
|
assert(!verify_cmos_op(bit, length));
|
|
result = 0;
|
|
|
|
for (next_bit = 0, bits_left = length;
|
|
bits_left;
|
|
next_bit += nr_bits, bits_left -= nr_bits)
|
|
{ nr_bits = cmos_bit_op_strategy(bit + next_bit, bits_left, &where);
|
|
value = cmos_read_bits(&where, nr_bits);
|
|
put_bits(value, next_bit, nr_bits, &result);
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_write
|
|
*
|
|
* Write 'data' to nonvolatile RAM at position given by 'bit' and 'length'.
|
|
* The I/O privilege level of the currently executing process must be set
|
|
* appropriately.
|
|
****************************************************************************/
|
|
void cmos_write (unsigned bit, unsigned length, unsigned long long value)
|
|
{ cmos_bit_op_location_t where;
|
|
unsigned next_bit, bits_left, nr_bits;
|
|
|
|
assert(!verify_cmos_op(bit, length));
|
|
|
|
for (next_bit = 0, bits_left = length;
|
|
bits_left;
|
|
next_bit += nr_bits, bits_left -= nr_bits)
|
|
{ nr_bits = cmos_bit_op_strategy(bit + next_bit, bits_left, &where);
|
|
cmos_write_bits(&where, nr_bits, get_bits(value, next_bit, nr_bits));
|
|
}
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_read_byte
|
|
*
|
|
* Read a byte from nonvolatile RAM at a position given by 'index' and return
|
|
* the result. An 'index' value of 0 represents the first byte of
|
|
* nonvolatile RAM.
|
|
*
|
|
* Note: the first 14 bytes of nonvolatile RAM provide an interface to the
|
|
* real time clock.
|
|
****************************************************************************/
|
|
unsigned char cmos_read_byte (unsigned index)
|
|
{ unsigned short port_0, port_1;
|
|
|
|
assert(!verify_cmos_byte_index(index));
|
|
|
|
if (index < 128)
|
|
{ port_0 = 0x70;
|
|
port_1 = 0x71;
|
|
}
|
|
else
|
|
{ port_0 = 0x72;
|
|
port_1 = 0x73;
|
|
}
|
|
|
|
outb(index, port_0);
|
|
return inb(port_1);
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_write_byte
|
|
*
|
|
* Write 'value' to nonvolatile RAM at a position given by 'index'. An
|
|
* 'index' of 0 represents the first byte of nonvolatile RAM.
|
|
*
|
|
* Note: the first 14 bytes of nonvolatile RAM provide an interface to the
|
|
* real time clock. Writing to any of these bytes will therefore
|
|
* affect its functioning.
|
|
****************************************************************************/
|
|
void cmos_write_byte (unsigned index, unsigned char value)
|
|
{ unsigned short port_0, port_1;
|
|
|
|
assert(!verify_cmos_byte_index(index));
|
|
|
|
if (index < 128)
|
|
{ port_0 = 0x70;
|
|
port_1 = 0x71;
|
|
}
|
|
else
|
|
{ port_0 = 0x72;
|
|
port_1 = 0x73;
|
|
}
|
|
|
|
outb(index, port_0);
|
|
outb(value, port_1);
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_read_all
|
|
*
|
|
* Read all contents of CMOS memory into array 'data'. The first 14 bytes of
|
|
* 'data' are set to zero since this corresponds to the real time clock area.
|
|
****************************************************************************/
|
|
void cmos_read_all (unsigned char data[])
|
|
{ unsigned i;
|
|
|
|
for (i = 0; i < CMOS_RTC_AREA_SIZE; i++)
|
|
data[i] = 0;
|
|
|
|
for (; i < CMOS_SIZE; i++)
|
|
data[i] = cmos_read_byte(i);
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_write_all
|
|
*
|
|
* Update all of CMOS memory with the contents of array 'data'. The first 14
|
|
* bytes of 'data' are ignored since this corresponds to the real time clock
|
|
* area.
|
|
****************************************************************************/
|
|
void cmos_write_all (unsigned char data[])
|
|
{ unsigned i;
|
|
|
|
for (i = CMOS_RTC_AREA_SIZE; i < CMOS_SIZE; i++)
|
|
cmos_write_byte(i, data[i]);
|
|
}
|
|
|
|
/****************************************************************************
|
|
* set_iopl
|
|
*
|
|
* Set the I/O privilege level of the executing process. Root privileges are
|
|
* required for performing this action. A sufficient I/O privilege level
|
|
* allows the process to access x86 I/O address space and to disable/reenable
|
|
* interrupts while executing in user space. Messing with the I/O privilege
|
|
* level is therefore somewhat dangerous.
|
|
****************************************************************************/
|
|
void set_iopl (int level)
|
|
{ assert((level >= 0) && (level <= 3));
|
|
|
|
if (iopl(level))
|
|
{ fprintf(stderr,
|
|
"%s: iopl() system call failed. You must be root to do "
|
|
"this.\n",
|
|
prog_name);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
/****************************************************************************
|
|
* verify_cmos_op
|
|
*
|
|
* 'bit' represents a bit position in the nonvolatile RAM. The first bit
|
|
* (i.e. the lowest order bit of the first byte) of nonvolatile RAM is
|
|
* labeled as bit 0. 'length' represents the width in bits of a value we
|
|
* wish to read or write. Perform sanity checking on 'bit' and 'length'. If
|
|
* no problems were encountered, return OK. Else return an error code.
|
|
****************************************************************************/
|
|
int verify_cmos_op (unsigned bit, unsigned length)
|
|
{ if ((bit >= (8 * CMOS_SIZE)) || ((bit + length) > (8 * CMOS_SIZE)))
|
|
return CMOS_AREA_OUT_OF_RANGE;
|
|
|
|
if (bit < (8 * CMOS_RTC_AREA_SIZE))
|
|
return CMOS_AREA_OVERLAPS_RTC;
|
|
|
|
if (length > (8 * sizeof(unsigned long long)))
|
|
return CMOS_AREA_TOO_WIDE;
|
|
|
|
return OK;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_bit_op_strategy
|
|
*
|
|
* Helper function used by cmos_read() and cmos_write() to determine which
|
|
* bits to read or write next.
|
|
****************************************************************************/
|
|
static unsigned cmos_bit_op_strategy (unsigned bit, unsigned bits_left,
|
|
cmos_bit_op_location_t *where)
|
|
{ unsigned max_bits;
|
|
|
|
where->byte_index = bit >> 3;
|
|
where->bit_offset = bit & 0x07;
|
|
max_bits = 8 - where->bit_offset;
|
|
return (bits_left > max_bits) ? max_bits : bits_left;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_read_bits
|
|
*
|
|
* Read a chunk of bits from a byte location within CMOS memory. Return the
|
|
* value represented by the chunk of bits.
|
|
****************************************************************************/
|
|
static unsigned char cmos_read_bits (const cmos_bit_op_location_t *where,
|
|
unsigned nr_bits)
|
|
{ return (cmos_read_byte(where->byte_index) >> where->bit_offset) &
|
|
((unsigned char) ((1 << nr_bits) - 1));
|
|
}
|
|
|
|
/****************************************************************************
|
|
* cmos_write_bits
|
|
*
|
|
* Write a chunk of bits (the low order 'nr_bits' bits of 'value') to an area
|
|
* within a particular byte of CMOS memory.
|
|
****************************************************************************/
|
|
static void cmos_write_bits (const cmos_bit_op_location_t *where,
|
|
unsigned nr_bits, unsigned char value)
|
|
{ unsigned char n, mask;
|
|
|
|
if (nr_bits == 8)
|
|
{ cmos_write_byte(where->byte_index, value);
|
|
return;
|
|
}
|
|
|
|
n = cmos_read_byte(where->byte_index);
|
|
mask = ((unsigned char) ((1 << nr_bits) - 1)) << where->bit_offset;
|
|
n = (n & ~mask) + ((value << where->bit_offset) & mask);
|
|
cmos_write_byte(where->byte_index, n);
|
|
}
|