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/*
* Copyright (C) 2021 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.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <ipxe/linux_api.h>
#include <ipxe/linux.h>
#include <ipxe/list.h>
#include <ipxe/init.h>
#include <ipxe/acpi.h>
/** ACPI sysfs directory */
#define ACPI_SYSFS_PREFIX "/sys/firmware/acpi/tables/"
/** A cached ACPI table */
struct linux_acpi_table {
/** List of cached tables */
struct list_head list;
/** Signature */
uint32_t signature;
/** Index */
unsigned int index;
/** Cached data */
void *data;
};
/** List of cached ACPI tables */
static LIST_HEAD ( linux_acpi_tables );
/**
* Locate ACPI table
*
* @v signature Requested table signature
* @v index Requested index of table with this signature
* @ret table Table, or UNULL if not found
*/
static userptr_t linux_acpi_find ( uint32_t signature, unsigned int index ) {
struct linux_acpi_table *table;
struct acpi_header header;
union {
uint32_t signature;
char filename[5];
} u;
static const char prefix[] = ACPI_SYSFS_PREFIX;
char filename[ sizeof ( prefix ) - 1 /* NUL */ + 4 /* signature */
+ 3 /* "999" */ + 1 /* NUL */ ];
ssize_t rlen;
size_t len;
void *data;
int fd;
/* Check for existing table */
list_for_each_entry ( table, &linux_acpi_tables, list ) {
if ( ( table->signature == signature ) &&
( table->index == index ) )
return virt_to_user ( table->data );
}
/* Allocate a new table */
table = malloc ( sizeof ( *table ) );
if ( ! table )
goto err_alloc;
table->signature = signature;
table->index = index;
/* Construct filename */
memset ( &u, 0, sizeof ( u ) );
u.signature = le32_to_cpu ( signature );
snprintf ( filename, sizeof ( filename ), "%s%s%d", prefix,
u.filename, ( index + 1 ) );
/* Open file */
fd = linux_open ( filename, O_RDONLY );
if ( ( fd < 0 ) && ( index == 0 ) ) {
filename[ sizeof ( prefix ) - 1 /* NUL */ +
4 /* signature */ ] = '\0';
fd = linux_open ( filename, O_RDONLY );
}
if ( fd < 0 ) {
DBGC ( &linux_acpi_tables, "ACPI could not open %s: %s\n",
filename, linux_strerror ( linux_errno ) );
goto err_open;
}
/* Read header */
rlen = linux_read ( fd, &header, sizeof ( header ) );
if ( rlen < 0 ) {
DBGC ( &linux_acpi_tables, "ACPI could not read %s header: "
"%s\n", filename, linux_strerror ( linux_errno ) );
goto err_header;
}
if ( ( ( size_t ) rlen ) != sizeof ( header ) ) {
DBGC ( &linux_acpi_tables, "ACPI underlength %s header\n",
filename );
goto err_header_len;
}
/* Parse header */
len = le32_to_cpu ( header.length );
if ( len < sizeof ( header ) ) {
DBGC ( &linux_acpi_tables, "ACPI malformed %s header\n",
filename );
goto err_malformed;
}
/* Allocate data */
table->data = malloc ( len );
if ( ! table->data )
goto err_data;
/* Read table */
memcpy ( table->data, &header, sizeof ( header ) );
data = ( table->data + sizeof ( header ) );
len -= sizeof ( header );
while ( len ) {
rlen = linux_read ( fd, data, len );
if ( rlen < 0 ) {
DBGC ( &linux_acpi_tables, "ACPI could not read %s: "
"%s\n", filename,
linux_strerror ( linux_errno ) );
goto err_body;
}
if ( rlen == 0 ) {
DBGC ( &linux_acpi_tables, "ACPI underlength %s\n",
filename );
goto err_body_len;
}
data += rlen;
len -= rlen;
}
/* Close file */
linux_close ( fd );
/* Add to list of tables */
list_add ( &table->list, &linux_acpi_tables );
DBGC ( &linux_acpi_tables, "ACPI cached %s\n", filename );
return virt_to_user ( table->data );
err_body_len:
err_body:
free ( table->data );
err_data:
err_malformed:
err_header_len:
err_header:
linux_close ( fd );
err_open:
free ( table );
err_alloc:
return UNULL;
}
/**
* Free cached ACPI data
*
*/
static void linux_acpi_shutdown ( int booting __unused ) {
struct linux_acpi_table *table;
struct linux_acpi_table *tmp;
list_for_each_entry_safe ( table, tmp, &linux_acpi_tables, list ) {
list_del ( &table->list );
free ( table->data );
free ( table );
}
}
/** ACPI shutdown function */
struct startup_fn linux_acpi_startup_fn __startup_fn ( STARTUP_NORMAL ) = {
.name = "linux_acpi",
.shutdown = linux_acpi_shutdown,
};
PROVIDE_ACPI ( linux, acpi_find, linux_acpi_find );
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