xref: /openbmc/linux/drivers/acpi/acpi_configfs.c (revision 82003e04)
1 /*
2  * ACPI configfs support
3  *
4  * Copyright (c) 2016 Intel Corporation
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published by
8  * the Free Software Foundation.
9  */
10 
11 #define pr_fmt(fmt) "ACPI configfs: " fmt
12 
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/configfs.h>
16 #include <linux/acpi.h>
17 
18 static struct config_group *acpi_table_group;
19 
20 struct acpi_table {
21 	struct config_item cfg;
22 	struct acpi_table_header *header;
23 };
24 
25 static ssize_t acpi_table_aml_write(struct config_item *cfg,
26 				    const void *data, size_t size)
27 {
28 	const struct acpi_table_header *header = data;
29 	struct acpi_table *table;
30 	int ret;
31 
32 	table = container_of(cfg, struct acpi_table, cfg);
33 
34 	if (table->header) {
35 		pr_err("table already loaded\n");
36 		return -EBUSY;
37 	}
38 
39 	if (header->length != size) {
40 		pr_err("invalid table length\n");
41 		return -EINVAL;
42 	}
43 
44 	if (memcmp(header->signature, ACPI_SIG_SSDT, 4)) {
45 		pr_err("invalid table signature\n");
46 		return -EINVAL;
47 	}
48 
49 	table = container_of(cfg, struct acpi_table, cfg);
50 
51 	table->header = kmemdup(header, header->length, GFP_KERNEL);
52 	if (!table->header)
53 		return -ENOMEM;
54 
55 	ret = acpi_load_table(table->header);
56 	if (ret) {
57 		kfree(table->header);
58 		table->header = NULL;
59 	}
60 
61 	return ret;
62 }
63 
64 static inline struct acpi_table_header *get_header(struct config_item *cfg)
65 {
66 	struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
67 
68 	if (!table->header)
69 		pr_err("table not loaded\n");
70 
71 	return table->header;
72 }
73 
74 static ssize_t acpi_table_aml_read(struct config_item *cfg,
75 				   void *data, size_t size)
76 {
77 	struct acpi_table_header *h = get_header(cfg);
78 
79 	if (!h)
80 		return -EINVAL;
81 
82 	if (data)
83 		memcpy(data, h, h->length);
84 
85 	return h->length;
86 }
87 
88 #define MAX_ACPI_TABLE_SIZE (128 * 1024)
89 
90 CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
91 
92 struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
93 	&acpi_table_attr_aml,
94 	NULL,
95 };
96 
97 ssize_t acpi_table_signature_show(struct config_item *cfg, char *str)
98 {
99 	struct acpi_table_header *h = get_header(cfg);
100 
101 	if (!h)
102 		return -EINVAL;
103 
104 	return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->signature);
105 }
106 
107 ssize_t acpi_table_length_show(struct config_item *cfg, char *str)
108 {
109 	struct acpi_table_header *h = get_header(cfg);
110 
111 	if (!h)
112 		return -EINVAL;
113 
114 	return sprintf(str, "%d\n", h->length);
115 }
116 
117 ssize_t acpi_table_revision_show(struct config_item *cfg, char *str)
118 {
119 	struct acpi_table_header *h = get_header(cfg);
120 
121 	if (!h)
122 		return -EINVAL;
123 
124 	return sprintf(str, "%d\n", h->revision);
125 }
126 
127 ssize_t acpi_table_oem_id_show(struct config_item *cfg, char *str)
128 {
129 	struct acpi_table_header *h = get_header(cfg);
130 
131 	if (!h)
132 		return -EINVAL;
133 
134 	return sprintf(str, "%.*s\n", ACPI_OEM_ID_SIZE, h->oem_id);
135 }
136 
137 ssize_t acpi_table_oem_table_id_show(struct config_item *cfg, char *str)
138 {
139 	struct acpi_table_header *h = get_header(cfg);
140 
141 	if (!h)
142 		return -EINVAL;
143 
144 	return sprintf(str, "%.*s\n", ACPI_OEM_TABLE_ID_SIZE, h->oem_table_id);
145 }
146 
147 ssize_t acpi_table_oem_revision_show(struct config_item *cfg, char *str)
148 {
149 	struct acpi_table_header *h = get_header(cfg);
150 
151 	if (!h)
152 		return -EINVAL;
153 
154 	return sprintf(str, "%d\n", h->oem_revision);
155 }
156 
157 ssize_t acpi_table_asl_compiler_id_show(struct config_item *cfg, char *str)
158 {
159 	struct acpi_table_header *h = get_header(cfg);
160 
161 	if (!h)
162 		return -EINVAL;
163 
164 	return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->asl_compiler_id);
165 }
166 
167 ssize_t acpi_table_asl_compiler_revision_show(struct config_item *cfg,
168 					      char *str)
169 {
170 	struct acpi_table_header *h = get_header(cfg);
171 
172 	if (!h)
173 		return -EINVAL;
174 
175 	return sprintf(str, "%d\n", h->asl_compiler_revision);
176 }
177 
178 CONFIGFS_ATTR_RO(acpi_table_, signature);
179 CONFIGFS_ATTR_RO(acpi_table_, length);
180 CONFIGFS_ATTR_RO(acpi_table_, revision);
181 CONFIGFS_ATTR_RO(acpi_table_, oem_id);
182 CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
183 CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
184 CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
185 CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);
186 
187 struct configfs_attribute *acpi_table_attrs[] = {
188 	&acpi_table_attr_signature,
189 	&acpi_table_attr_length,
190 	&acpi_table_attr_revision,
191 	&acpi_table_attr_oem_id,
192 	&acpi_table_attr_oem_table_id,
193 	&acpi_table_attr_oem_revision,
194 	&acpi_table_attr_asl_compiler_id,
195 	&acpi_table_attr_asl_compiler_revision,
196 	NULL,
197 };
198 
199 static struct config_item_type acpi_table_type = {
200 	.ct_owner = THIS_MODULE,
201 	.ct_bin_attrs = acpi_table_bin_attrs,
202 	.ct_attrs = acpi_table_attrs,
203 };
204 
205 static struct config_item *acpi_table_make_item(struct config_group *group,
206 						const char *name)
207 {
208 	struct acpi_table *table;
209 
210 	table = kzalloc(sizeof(*table), GFP_KERNEL);
211 	if (!table)
212 		return ERR_PTR(-ENOMEM);
213 
214 	config_item_init_type_name(&table->cfg, name, &acpi_table_type);
215 	return &table->cfg;
216 }
217 
218 struct configfs_group_operations acpi_table_group_ops = {
219 	.make_item = acpi_table_make_item,
220 };
221 
222 static struct config_item_type acpi_tables_type = {
223 	.ct_owner = THIS_MODULE,
224 	.ct_group_ops = &acpi_table_group_ops,
225 };
226 
227 static struct config_item_type acpi_root_group_type = {
228 	.ct_owner = THIS_MODULE,
229 };
230 
231 static struct configfs_subsystem acpi_configfs = {
232 	.su_group = {
233 		.cg_item = {
234 			.ci_namebuf = "acpi",
235 			.ci_type = &acpi_root_group_type,
236 		},
237 	},
238 	.su_mutex = __MUTEX_INITIALIZER(acpi_configfs.su_mutex),
239 };
240 
241 static int __init acpi_configfs_init(void)
242 {
243 	int ret;
244 	struct config_group *root = &acpi_configfs.su_group;
245 
246 	config_group_init(root);
247 
248 	ret = configfs_register_subsystem(&acpi_configfs);
249 	if (ret)
250 		return ret;
251 
252 	acpi_table_group = configfs_register_default_group(root, "table",
253 							   &acpi_tables_type);
254 	return PTR_ERR_OR_ZERO(acpi_table_group);
255 }
256 module_init(acpi_configfs_init);
257 
258 static void __exit acpi_configfs_exit(void)
259 {
260 	configfs_unregister_default_group(acpi_table_group);
261 	configfs_unregister_subsystem(&acpi_configfs);
262 }
263 module_exit(acpi_configfs_exit);
264 
265 MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
266 MODULE_DESCRIPTION("ACPI configfs support");
267 MODULE_LICENSE("GPL v2");
268