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
 18static struct config_group *acpi_table_group;
 19
 20struct acpi_table {
 21	struct config_item cfg;
 22	struct acpi_table_header *header;
 23};
 24
 25static 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
 64static 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
 74static 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
 90CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
 91
 92struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
 93	&acpi_table_attr_aml,
 94	NULL,
 95};
 96
 97ssize_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
107ssize_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
117ssize_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
127ssize_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
137ssize_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
147ssize_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
157ssize_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
167ssize_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
178CONFIGFS_ATTR_RO(acpi_table_, signature);
179CONFIGFS_ATTR_RO(acpi_table_, length);
180CONFIGFS_ATTR_RO(acpi_table_, revision);
181CONFIGFS_ATTR_RO(acpi_table_, oem_id);
182CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
183CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
184CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
185CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);
186
187struct 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
199static 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
205static 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
218struct configfs_group_operations acpi_table_group_ops = {
219	.make_item = acpi_table_make_item,
220};
221
222static struct config_item_type acpi_tables_type = {
223	.ct_owner = THIS_MODULE,
224	.ct_group_ops = &acpi_table_group_ops,
225};
226
227static struct config_item_type acpi_root_group_type = {
228	.ct_owner = THIS_MODULE,
229};
230
231static 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
241static 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}
256module_init(acpi_configfs_init);
257
258static void __exit acpi_configfs_exit(void)
259{
260	configfs_unregister_default_group(acpi_table_group);
261	configfs_unregister_subsystem(&acpi_configfs);
262}
263module_exit(acpi_configfs_exit);
264
265MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
266MODULE_DESCRIPTION("ACPI configfs support");
267MODULE_LICENSE("GPL v2");