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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 <acpi/acpi.h>
64 
65 #include <linux/sfi.h>
66 #include "sfi_core.h"
67 
68 /*
69  * SFI can access ACPI-defined tables via an optional ACPI XSDT.
70  *
71  * This allows re-use, and avoids re-definition, of standard tables.
72  * For example, the "MCFG" table is defined by PCI, reserved by ACPI,
73  * and is expected to be present many SFI-only systems.
74  */
75 
76 static struct acpi_table_xsdt *xsdt_va __read_mostly;
77 
78 #define XSDT_GET_NUM_ENTRIES(ptable, entry_type) \
79  ((ptable->header.length - sizeof(struct acpi_table_header)) / \
80  (sizeof(entry_type)))
81 
82 static inline struct sfi_table_header *acpi_to_sfi_th(
83  struct acpi_table_header *th)
84 {
85  return (struct sfi_table_header *)th;
86 }
87 
88 static inline struct acpi_table_header *sfi_to_acpi_th(
89  struct sfi_table_header *th)
90 {
91  return (struct acpi_table_header *)th;
92 }
93 
94 /*
95  * sfi_acpi_parse_xsdt()
96  *
97  * Parse the ACPI XSDT for later access by sfi_acpi_table_parse().
98  */
99 static int __init sfi_acpi_parse_xsdt(struct sfi_table_header *th)
100 {
101  struct sfi_table_key key = SFI_ANY_KEY;
102  int tbl_cnt, i;
103  void *ret;
104 
105  xsdt_va = (struct acpi_table_xsdt *)th;
106  tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
107  for (i = 0; i < tbl_cnt; i++) {
108  ret = sfi_check_table(xsdt_va->table_offset_entry[i], &key);
109  if (IS_ERR(ret)) {
110  disable_sfi();
111  return -1;
112  }
113  }
114 
115  return 0;
116 }
117 
119 {
120  struct sfi_table_key xsdt_key = { .sig = SFI_SIG_XSDT };
121 
122  sfi_table_parse(SFI_SIG_XSDT, NULL, NULL, sfi_acpi_parse_xsdt);
123 
124  /* Only call the get_table to keep the table mapped */
125  xsdt_va = (struct acpi_table_xsdt *)sfi_get_table(&xsdt_key);
126  return 0;
127 }
128 
129 static struct acpi_table_header *sfi_acpi_get_table(struct sfi_table_key *key)
130 {
131  u32 tbl_cnt, i;
132  void *ret;
133 
134  tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
135  for (i = 0; i < tbl_cnt; i++) {
136  ret = sfi_check_table(xsdt_va->table_offset_entry[i], key);
137  if (!IS_ERR(ret) && ret)
138  return sfi_to_acpi_th(ret);
139  }
140 
141  return NULL;
142 }
143 
144 static void sfi_acpi_put_table(struct acpi_table_header *table)
145 {
146  sfi_put_table(acpi_to_sfi_th(table));
147 }
148 
149 /*
150  * sfi_acpi_table_parse()
151  *
152  * Find specified table in XSDT, run handler on it and return its return value
153  */
155  int(*handler)(struct acpi_table_header *))
156 {
157  struct acpi_table_header *table = NULL;
158  struct sfi_table_key key;
159  int ret = 0;
160 
161  if (sfi_disabled)
162  return -1;
163 
164  key.sig = signature;
165  key.oem_id = oem_id;
167 
168  table = sfi_acpi_get_table(&key);
169  if (!table)
170  return -EINVAL;
171 
172  ret = handler(table);
173  sfi_acpi_put_table(table);
174  return ret;
175 }
176 
177 static ssize_t sfi_acpi_table_show(struct file *filp, struct kobject *kobj,
178  struct bin_attribute *bin_attr, char *buf,
179  loff_t offset, size_t count)
180 {
181  struct sfi_table_attr *tbl_attr =
182  container_of(bin_attr, struct sfi_table_attr, attr);
183  struct acpi_table_header *th = NULL;
184  struct sfi_table_key key;
185  ssize_t cnt;
186 
187  key.sig = tbl_attr->name;
188  key.oem_id = NULL;
189  key.oem_table_id = NULL;
190 
191  th = sfi_acpi_get_table(&key);
192  if (!th)
193  return 0;
194 
195  cnt = memory_read_from_buffer(buf, count, &offset,
196  th, th->length);
197  sfi_acpi_put_table(th);
198 
199  return cnt;
200 }
201 
202 
204 {
205  u32 tbl_cnt, i;
206  struct sfi_table_attr *tbl_attr;
207 
208  tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
209  for (i = 0; i < tbl_cnt; i++) {
210  tbl_attr =
211  sfi_sysfs_install_table(xsdt_va->table_offset_entry[i]);
212  tbl_attr->attr.read = sfi_acpi_table_show;
213  }
214 
215  return;
216 }