/*
* Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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; either version 2 of the
* License, or any later version.
*
* 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 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 Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <unistd.h>
#include <errno.h>
#include <byteswap.h>
#include <ipxe/io.h>
#include <ipxe/acpi.h>
#include <ipxe/acpipwr.h>
/** @file
*
* ACPI power off
*
*/
/** Colour for debug messages */
#define colour FADT_SIGNATURE
/** _S5_ signature */
#define S5_SIGNATURE ACPI_SIGNATURE ( '_', 'S', '5', '_' )
/**
* Extract \_Sx value from DSDT/SSDT
*
* @v zsdt DSDT or SSDT
* @v len Length of DSDT/SSDT
* @v offset Offset of signature within DSDT/SSDT
* @v data Data buffer
* @ret rc Return status code
*
* In theory, extracting the \_Sx value from the DSDT/SSDT requires a
* full ACPI parser plus some heuristics to work around the various
* broken encodings encountered in real ACPI implementations.
*
* In practice, we can get the same result by scanning through the
* DSDT/SSDT for the signature (e.g. "_S5_"), extracting the first
* four bytes, removing any bytes with bit 3 set, and treating
* whatever is left as a little-endian value. This is one of the
* uglier hacks I have ever implemented, but it's still prettier than
* the ACPI specification itself.
*/
static int acpi_extract_sx ( userptr_t zsdt, size_t len, size_t offset,
void *data ) {
unsigned int *sx = data;
uint8_t bytes[4];
uint8_t *byte;
/* Skip signature and package header */
offset += ( 4 /* signature */ + 3 /* package header */ );
/* Sanity check */
if ( ( offset + sizeof ( bytes ) /* value */ ) > len ) {
return -EINVAL;
}
/* Read first four bytes of value */
copy_from_user ( bytes, zsdt, offset, sizeof ( bytes ) );
DBGC ( colour, "ACPI found \\_Sx containing %02x:%02x:%02x:%02x\n",
bytes[0], bytes[1], bytes[2], bytes[3] );
/* Extract \Sx value. There are three potential encodings
* that we might encounter:
*
* - SLP_TYPa, SLP_TYPb, rsvd, rsvd
*
* - <byteprefix>, SLP_TYPa, <byteprefix>, SLP_TYPb, ...
*
* - <dwordprefix>, SLP_TYPa, SLP_TYPb, 0, 0
*
* Since <byteprefix> and <dwordprefix> both have bit 3 set,
* and valid SLP_TYPx must have bit 3 clear (since SLP_TYPx is
* a 3-bit field), we can just skip any bytes with bit 3 set.
*/
byte = bytes;
if ( *byte & 0x08 )
byte++;
*sx = *(byte++);
if ( *byte & 0x08 )
byte++;
*sx |= ( *byte << 8 );
return 0;
}
/**
* Power off the computer using ACPI
*
* @ret rc Return status code
*/
int acpi_poweroff ( void ) {
struct acpi_fadt fadtab;
userptr_t fadt;
unsigned int pm1a_cnt_blk;
unsigned int pm1b_cnt_blk;
unsigned int pm1a_cnt;
unsigned int pm1b_cnt;
unsigned int slp_typa;
unsigned int slp_typb;
unsigned int s5;
int rc;
/* Locate FADT */
fadt = acpi_table ( FADT_SIGNATURE, 0 );
if ( ! fadt ) {
DBGC ( colour, "ACPI could not find FADT\n" );
return -ENOENT;
}
/* Read FADT */
copy_from_user ( &fadtab, fadt, 0, sizeof ( fadtab ) );
pm1a_cnt_blk = le32_to_cpu ( fadtab.pm1a_cnt_blk );
pm1b_cnt_blk = le32_to_cpu ( fadtab.pm1b_cnt_blk );
pm1a_cnt = ( pm1a_cnt_blk + ACPI_PM1_CNT );
pm1b_cnt = ( pm1b_cnt_blk + ACPI_PM1_CNT );
/* Extract \_S5 from DSDT or any SSDT */
if ( ( rc = acpi_extract ( S5_SIGNATURE, &s5,
acpi_extract_sx ) ) != 0 ) {
DBGC ( colour, "ACPI could not extract \\_S5: %s\n",
strerror ( rc ) );
return rc;
}
/* Power off system */
if ( pm1a_cnt_blk ) {
slp_typa = ( ( s5 >> 0 ) & 0xff );
DBGC ( colour, "ACPI PM1a sleep type %#x => %04x\n",
slp_typa, pm1a_cnt );
outw ( ( ACPI_PM1_CNT_SLP_TYP ( slp_typa ) |
ACPI_PM1_CNT_SLP_EN ), pm1a_cnt );
}
if ( pm1b_cnt_blk ) {
slp_typb = ( ( s5 >> 8 ) & 0xff );
DBGC ( colour, "ACPI PM1b sleep type %#x => %04x\n",
slp_typb, pm1b_cnt );
outw ( ( ACPI_PM1_CNT_SLP_TYP ( slp_typb ) |
ACPI_PM1_CNT_SLP_EN ), pm1b_cnt );
}
/* On some systems, execution will continue briefly. Delay to
* avoid potentially confusing log messages.
*/
mdelay ( 1000 );
DBGC ( colour, "ACPI power off failed\n" );
return -EPROTO;
}
