| /*****************************************************************************\ |
| * cmos_lowlevel.c |
| ***************************************************************************** |
| * 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., |
| * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| \*****************************************************************************/ |
| |
| #if defined(__FreeBSD__) |
| #include <fcntl.h> |
| #include <unistd.h> |
| #endif |
| |
| #include "common.h" |
| #include "cmos_lowlevel.h" |
| |
| /* Hardware Abstraction Layer: lowlevel byte-wise write access */ |
| |
| extern cmos_access_t cmos_hal, memory_hal; |
| static cmos_access_t *current_access = &cmos_hal; |
| |
| void select_hal(hal_t hal, void *data) |
| { |
| switch(hal) { |
| case HAL_CMOS: |
| current_access = &cmos_hal; |
| break; |
| case HAL_MEMORY: |
| current_access = &memory_hal; |
| break; |
| } |
| current_access->init(data); |
| } |
| |
| /* Bit-level access */ |
| 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 += ((unsigned long long)(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(const cmos_entry_t * e) |
| { |
| cmos_bit_op_location_t where; |
| unsigned bit = e->bit, length = e->length; |
| unsigned next_bit, bits_left, nr_bits; |
| unsigned long long result = 0; |
| unsigned char value; |
| |
| assert(!verify_cmos_op(bit, length, e->config)); |
| result = 0; |
| |
| if (e->config == CMOS_ENTRY_STRING) { |
| char *newstring = calloc(1, (length + 7) / 8); |
| unsigned usize = (8 * sizeof(unsigned long long)); |
| |
| if (!newstring) { |
| out_of_memory(); |
| } |
| |
| 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 > usize ? usize : bits_left, &where); |
| value = cmos_read_bits(&where, nr_bits); |
| put_bits(value, next_bit % usize, nr_bits, |
| &((unsigned long long *)newstring)[next_bit / |
| usize]); |
| result = (unsigned long)newstring; |
| } |
| } else { |
| 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(const cmos_entry_t * e, unsigned long long value) |
| { |
| cmos_bit_op_location_t where; |
| unsigned bit = e->bit, length = e->length; |
| unsigned next_bit, bits_left, nr_bits; |
| |
| assert(!verify_cmos_op(bit, length, e->config)); |
| |
| if (e->config == CMOS_ENTRY_STRING) { |
| unsigned long long *data = |
| (unsigned long long *)(unsigned long)value; |
| unsigned usize = (8 * sizeof(unsigned long long)); |
| |
| 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 > usize ? usize : bits_left, |
| &where); |
| value = data[next_bit / usize]; |
| cmos_write_bits(&where, nr_bits, |
| get_bits(value, next_bit % usize, nr_bits)); |
| } |
| } else { |
| 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) |
| { |
| return current_access->read(index); |
| } |
| |
| /**************************************************************************** |
| * 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) |
| { |
| current_access->write(index, value); |
| } |
| |
| /**************************************************************************** |
| * 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) |
| { |
| current_access->set_iopl(level); |
| } |
| |
| /**************************************************************************** |
| * 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, cmos_entry_config_t config) |
| { |
| 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 (config == CMOS_ENTRY_STRING) |
| return OK; |
| |
| 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); |
| } |