162 lines
4.2 KiB
C
162 lines
4.2 KiB
C
/*
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* Copyright (C) 2017 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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/**
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* @file
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*
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* ACPI settings
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*
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*/
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#include <string.h>
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#include <errno.h>
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#include <ipxe/init.h>
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#include <ipxe/settings.h>
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#include <ipxe/acpi.h>
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/** ACPI settings scope */
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static const struct settings_scope acpi_settings_scope;
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/**
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* Check applicability of ACPI setting
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*
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* @v settings Settings block
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* @v setting Setting
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* @ret applies Setting applies within this settings block
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*/
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static int acpi_settings_applies ( struct settings *settings __unused,
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const struct setting *setting ) {
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return ( setting->scope == &acpi_settings_scope );
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}
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/**
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* Fetch value of ACPI setting
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*
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* @v settings Settings block
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* @v setting Setting to fetch
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* @v data Buffer to fill with setting data
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* @v len Length of buffer
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* @ret len Length of setting data, or negative error
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*/
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static int acpi_settings_fetch ( struct settings *settings,
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struct setting *setting,
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void *data, size_t len ) {
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struct acpi_header acpi;
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uint32_t tag_high;
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uint32_t tag_low;
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uint32_t tag_signature;
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unsigned int tag_index;
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size_t tag_offset;
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size_t tag_len;
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userptr_t table;
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size_t offset;
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size_t max_len;
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int delta;
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unsigned int i;
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/* Parse settings tag */
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tag_high = ( setting->tag >> 32 );
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tag_low = setting->tag;
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tag_signature = bswap_32 ( tag_high );
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tag_index = ( ( tag_low >> 24 ) & 0xff );
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tag_offset = ( ( tag_low >> 8 ) & 0xffff );
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tag_len = ( ( tag_low >> 0 ) & 0xff );
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DBGC ( settings, "ACPI %s.%d offset %#zx length %#zx\n",
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acpi_name ( tag_signature ), tag_index, tag_offset, tag_len );
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/* Locate ACPI table */
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table = acpi_find ( tag_signature, tag_index );
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if ( ! table )
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return -ENOENT;
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/* Read table header */
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copy_from_user ( &acpi, table, 0, sizeof ( acpi ) );
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/* Calculate starting offset and maximum available length */
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max_len = le32_to_cpu ( acpi.length );
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if ( tag_offset > max_len )
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return -ENOENT;
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offset = tag_offset;
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max_len -= offset;
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/* Restrict to requested length, if specified */
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if ( tag_len && ( tag_len < max_len ) )
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max_len = tag_len;
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/* Invert endianness for numeric settings */
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if ( setting->type && setting->type->numerate ) {
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offset += ( max_len - 1 );
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delta = -1;
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} else {
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delta = +1;
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}
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/* Read data */
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for ( i = 0 ; ( ( i < max_len ) && ( i < len ) ) ; i++ ) {
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copy_from_user ( data, table, offset, 1 );
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data++;
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offset += delta;
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}
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/* Set type if not already specified */
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if ( ! setting->type )
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setting->type = &setting_type_hexraw;
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return max_len;
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}
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/** ACPI settings operations */
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static struct settings_operations acpi_settings_operations = {
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.applies = acpi_settings_applies,
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.fetch = acpi_settings_fetch,
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};
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/** ACPI settings */
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static struct settings acpi_settings = {
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.refcnt = NULL,
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.siblings = LIST_HEAD_INIT ( acpi_settings.siblings ),
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.children = LIST_HEAD_INIT ( acpi_settings.children ),
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.op = &acpi_settings_operations,
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.default_scope = &acpi_settings_scope,
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};
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/** Initialise ACPI settings */
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static void acpi_settings_init ( void ) {
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int rc;
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if ( ( rc = register_settings ( &acpi_settings, NULL,
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"acpi" ) ) != 0 ) {
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DBG ( "ACPI could not register settings: %s\n",
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strerror ( rc ) );
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return;
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}
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}
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/** ACPI settings initialiser */
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struct init_fn acpi_settings_init_fn __init_fn ( INIT_NORMAL ) = {
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.initialise = acpi_settings_init,
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};
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