linux/drivers/sfi/sfi_acpi.c
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   1/* sfi_acpi.c Simple Firmware Interface - ACPI extensions */
   2
   3/*
   4
   5  This file is provided under a dual BSD/GPLv2 license.  When using or
   6  redistributing this file, you may do so under either license.
   7
   8  GPL LICENSE SUMMARY
   9
  10  Copyright(c) 2009 Intel Corporation. All rights reserved.
  11
  12  This program is free software; you can redistribute it and/or modify
  13  it under the terms of version 2 of the GNU General Public License as
  14  published by the Free Software Foundation.
  15
  16  This program is distributed in the hope that it will be useful, but
  17  WITHOUT ANY WARRANTY; without even the implied warranty of
  18  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  General Public License for more details.
  20
  21  You should have received a copy of the GNU General Public License
  22  along with this program; if not, write to the Free Software
  23  Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  24  The full GNU General Public License is included in this distribution
  25  in the file called LICENSE.GPL.
  26
  27  BSD LICENSE
  28
  29  Copyright(c) 2009 Intel Corporation. All rights reserved.
  30
  31  Redistribution and use in source and binary forms, with or without
  32  modification, are permitted provided that the following conditions
  33  are met:
  34
  35    * Redistributions of source code must retain the above copyright
  36      notice, this list of conditions and the following disclaimer.
  37    * Redistributions in binary form must reproduce the above copyright
  38      notice, this list of conditions and the following disclaimer in
  39      the documentation and/or other materials provided with the
  40      distribution.
  41    * Neither the name of Intel Corporation nor the names of its
  42      contributors may be used to endorse or promote products derived
  43      from this software without specific prior written permission.
  44
  45  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  46  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  47  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  48  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  49  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  50  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  51  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  52  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  53  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  54  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  55  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  56
  57*/
  58
  59#define KMSG_COMPONENT "SFI"
  60#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  61
  62#include <linux/kernel.h>
  63#include <linux/sfi_acpi.h>
  64#include "sfi_core.h"
  65
  66/*
  67 * SFI can access ACPI-defined tables via an optional ACPI XSDT.
  68 *
  69 * This allows re-use, and avoids re-definition, of standard tables.
  70 * For example, the "MCFG" table is defined by PCI, reserved by ACPI,
  71 * and is expected to be present many SFI-only systems.
  72 */
  73
  74static struct acpi_table_xsdt *xsdt_va __read_mostly;
  75
  76#define XSDT_GET_NUM_ENTRIES(ptable, entry_type) \
  77        ((ptable->header.length - sizeof(struct acpi_table_header)) / \
  78        (sizeof(entry_type)))
  79
  80static inline struct sfi_table_header *acpi_to_sfi_th(
  81                                struct acpi_table_header *th)
  82{
  83        return (struct sfi_table_header *)th;
  84}
  85
  86static inline struct acpi_table_header *sfi_to_acpi_th(
  87                                struct sfi_table_header *th)
  88{
  89        return (struct acpi_table_header *)th;
  90}
  91
  92/*
  93 * sfi_acpi_parse_xsdt()
  94 *
  95 * Parse the ACPI XSDT for later access by sfi_acpi_table_parse().
  96 */
  97static int __init sfi_acpi_parse_xsdt(struct sfi_table_header *th)
  98{
  99        struct sfi_table_key key = SFI_ANY_KEY;
 100        int tbl_cnt, i;
 101        void *ret;
 102
 103        xsdt_va = (struct acpi_table_xsdt *)th;
 104        tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
 105        for (i = 0; i < tbl_cnt; i++) {
 106                ret = sfi_check_table(xsdt_va->table_offset_entry[i], &key);
 107                if (IS_ERR(ret)) {
 108                        disable_sfi();
 109                        return -1;
 110                }
 111        }
 112
 113        return 0;
 114}
 115
 116int __init sfi_acpi_init(void)
 117{
 118        struct sfi_table_key xsdt_key = { .sig = SFI_SIG_XSDT };
 119
 120        sfi_table_parse(SFI_SIG_XSDT, NULL, NULL, sfi_acpi_parse_xsdt);
 121
 122        /* Only call the get_table to keep the table mapped */
 123        xsdt_va = (struct acpi_table_xsdt *)sfi_get_table(&xsdt_key);
 124        return 0;
 125}
 126
 127static struct acpi_table_header *sfi_acpi_get_table(struct sfi_table_key *key)
 128{
 129        u32 tbl_cnt, i;
 130        void *ret;
 131
 132        tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
 133        for (i = 0; i < tbl_cnt; i++) {
 134                ret = sfi_check_table(xsdt_va->table_offset_entry[i], key);
 135                if (!IS_ERR(ret) && ret)
 136                        return sfi_to_acpi_th(ret);
 137        }
 138
 139        return NULL;
 140}
 141
 142static void sfi_acpi_put_table(struct acpi_table_header *table)
 143{
 144        sfi_put_table(acpi_to_sfi_th(table));
 145}
 146
 147/*
 148 * sfi_acpi_table_parse()
 149 *
 150 * Find specified table in XSDT, run handler on it and return its return value
 151 */
 152int sfi_acpi_table_parse(char *signature, char *oem_id, char *oem_table_id,
 153                        int(*handler)(struct acpi_table_header *))
 154{
 155        struct acpi_table_header *table = NULL;
 156        struct sfi_table_key key;
 157        int ret = 0;
 158
 159        if (sfi_disabled)
 160                return -1;
 161
 162        key.sig = signature;
 163        key.oem_id = oem_id;
 164        key.oem_table_id = oem_table_id;
 165
 166        table = sfi_acpi_get_table(&key);
 167        if (!table)
 168                return -EINVAL;
 169
 170        ret = handler(table);
 171        sfi_acpi_put_table(table);
 172        return ret;
 173}
 174
 175static ssize_t sfi_acpi_table_show(struct file *filp, struct kobject *kobj,
 176                               struct bin_attribute *bin_attr, char *buf,
 177                               loff_t offset, size_t count)
 178{
 179        struct sfi_table_attr *tbl_attr =
 180            container_of(bin_attr, struct sfi_table_attr, attr);
 181        struct acpi_table_header *th = NULL;
 182        struct sfi_table_key key;
 183        ssize_t cnt;
 184
 185        key.sig = tbl_attr->name;
 186        key.oem_id = NULL;
 187        key.oem_table_id = NULL;
 188
 189        th = sfi_acpi_get_table(&key);
 190        if (!th)
 191                return 0;
 192
 193        cnt =  memory_read_from_buffer(buf, count, &offset,
 194                                        th, th->length);
 195        sfi_acpi_put_table(th);
 196
 197        return cnt;
 198}
 199
 200
 201void __init sfi_acpi_sysfs_init(void)
 202{
 203        u32 tbl_cnt, i;
 204        struct sfi_table_attr *tbl_attr;
 205
 206        tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
 207        for (i = 0; i < tbl_cnt; i++) {
 208                tbl_attr =
 209                        sfi_sysfs_install_table(xsdt_va->table_offset_entry[i]);
 210                tbl_attr->attr.read = sfi_acpi_table_show;
 211        }
 212
 213        return;
 214}
 215