From 356f6c1b64d7a97746d1816cef8ca22bdd8d0b5d Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Tue, 23 May 2017 15:44:22 +0100 Subject: [acpi] Expose ACPI tables via settings mechanism Allow values to be read from ACPI tables using the syntax ${acpi/..0..} where is the ACPI table signature as a 32-bit hexadecimal number (e.g. 0x41504093 for the 'APIC' signature on the MADT), is the index into the array of tables matching this signature, is the byte offset within the table, and is the field length in bytes. Numeric values are returned in reverse byte order, since ACPI numeric values are usually little-endian. For example: ${acpi/0x41504943.0.0.0.0} - entire MADT table in raw hex ${acpi/0x41504943.0.0.0x0a.6:string} - MADT table OEM ID ${acpi/0x41504943.0.0.0x24.4:uint32} - local APIC address Signed-off-by: Michael Brown --- src/core/acpi_settings.c | 161 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 161 insertions(+) create mode 100644 src/core/acpi_settings.c (limited to 'src/core') diff --git a/src/core/acpi_settings.c b/src/core/acpi_settings.c new file mode 100644 index 00000000..7ba2e979 --- /dev/null +++ b/src/core/acpi_settings.c @@ -0,0 +1,161 @@ +/* + * Copyright (C) 2017 Michael Brown . + * + * 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 ); + +/** + * @file + * + * ACPI settings + * + */ + +#include +#include +#include +#include +#include + +/** ACPI settings scope */ +static const struct settings_scope acpi_settings_scope; + +/** + * Check applicability of ACPI setting + * + * @v settings Settings block + * @v setting Setting + * @ret applies Setting applies within this settings block + */ +static int acpi_settings_applies ( struct settings *settings __unused, + const struct setting *setting ) { + + return ( setting->scope == &acpi_settings_scope ); +} + +/** + * Fetch value of ACPI setting + * + * @v settings Settings block + * @v setting Setting to fetch + * @v data Buffer to fill with setting data + * @v len Length of buffer + * @ret len Length of setting data, or negative error + */ +static int acpi_settings_fetch ( struct settings *settings, + struct setting *setting, + void *data, size_t len ) { + struct acpi_header acpi; + uint32_t tag_high; + uint32_t tag_low; + uint32_t tag_signature; + unsigned int tag_index; + size_t tag_offset; + size_t tag_len; + userptr_t table; + size_t offset; + size_t max_len; + int delta; + unsigned int i; + + /* Parse settings tag */ + tag_high = ( setting->tag >> 32 ); + tag_low = setting->tag; + tag_signature = bswap_32 ( tag_high ); + tag_index = ( ( tag_low >> 24 ) & 0xff ); + tag_offset = ( ( tag_low >> 8 ) & 0xffff ); + tag_len = ( ( tag_low >> 0 ) & 0xff ); + DBGC ( settings, "ACPI %s.%d offset %#zx length %#zx\n", + acpi_name ( tag_signature ), tag_index, tag_offset, tag_len ); + + /* Locate ACPI table */ + table = acpi_find ( tag_signature, tag_index ); + if ( ! table ) + return -ENOENT; + + /* Read table header */ + copy_from_user ( &acpi, table, 0, sizeof ( acpi ) ); + + /* Calculate starting offset and maximum available length */ + max_len = le32_to_cpu ( acpi.length ); + if ( tag_offset > max_len ) + return -ENOENT; + offset = tag_offset; + max_len -= offset; + + /* Restrict to requested length, if specified */ + if ( tag_len && ( tag_len < max_len ) ) + max_len = tag_len; + + /* Invert endianness for numeric settings */ + if ( setting->type && setting->type->numerate ) { + offset += ( max_len - 1 ); + delta = -1; + } else { + delta = +1; + } + + /* Read data */ + for ( i = 0 ; ( ( i < max_len ) && ( i < len ) ) ; i++ ) { + copy_from_user ( data, table, offset, 1 ); + data++; + offset += delta; + } + + /* Set type if not already specified */ + if ( ! setting->type ) + setting->type = &setting_type_hexraw; + + return max_len; +} + +/** ACPI settings operations */ +static struct settings_operations acpi_settings_operations = { + .applies = acpi_settings_applies, + .fetch = acpi_settings_fetch, +}; + +/** ACPI settings */ +static struct settings acpi_settings = { + .refcnt = NULL, + .siblings = LIST_HEAD_INIT ( acpi_settings.siblings ), + .children = LIST_HEAD_INIT ( acpi_settings.children ), + .op = &acpi_settings_operations, + .default_scope = &acpi_settings_scope, +}; + +/** Initialise ACPI settings */ +static void acpi_settings_init ( void ) { + int rc; + + if ( ( rc = register_settings ( &acpi_settings, NULL, + "acpi" ) ) != 0 ) { + DBG ( "ACPI could not register settings: %s\n", + strerror ( rc ) ); + return; + } +} + +/** ACPI settings initialiser */ +struct init_fn acpi_settings_init_fn __init_fn ( INIT_NORMAL ) = { + .initialise = acpi_settings_init, +}; -- cgit v1.2.3-55-g7522