1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * ACPI configfs support
  4 *
  5 * Copyright (c) 2016 Intel Corporation
  6 */
  7
  8#define pr_fmt(fmt) "ACPI configfs: " fmt
  9
 10#include <linux/init.h>
 11#include <linux/module.h>
 12#include <linux/configfs.h>
 13#include <linux/acpi.h>
 14
 15#include "acpica/accommon.h"
 16#include "acpica/actables.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	u32 index;
 24};
 25
 26static ssize_t acpi_table_aml_write(struct config_item *cfg,
 27				    const void *data, size_t size)
 28{
 29	const struct acpi_table_header *header = data;
 30	struct acpi_table *table;
 31	int ret;
 32
 33	table = container_of(cfg, struct acpi_table, cfg);
 34
 35	if (table->header) {
 36		pr_err("table already loaded\n");
 37		return -EBUSY;
 38	}
 39
 40	if (header->length != size) {
 41		pr_err("invalid table length\n");
 42		return -EINVAL;
 43	}
 44
 45	if (memcmp(header->signature, ACPI_SIG_SSDT, 4)) {
 46		pr_err("invalid table signature\n");
 47		return -EINVAL;
 48	}
 49
 50	table = container_of(cfg, struct acpi_table, cfg);
 51
 52	table->header = kmemdup(header, header->length, GFP_KERNEL);
 53	if (!table->header)
 54		return -ENOMEM;
 55
 56	ret = acpi_load_table(table->header);
 57	if (ret) {
 58		kfree(table->header);
 59		table->header = NULL;
 60	}
 61
 62	return ret;
 63}
 64
 65static inline struct acpi_table_header *get_header(struct config_item *cfg)
 66{
 67	struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
 68
 69	if (!table->header)
 70		pr_err("table not loaded\n");
 71
 72	return table->header;
 73}
 74
 75static ssize_t acpi_table_aml_read(struct config_item *cfg,
 76				   void *data, size_t size)
 77{
 78	struct acpi_table_header *h = get_header(cfg);
 79
 80	if (!h)
 81		return -EINVAL;
 82
 83	if (data)
 84		memcpy(data, h, h->length);
 85
 86	return h->length;
 87}
 88
 89#define MAX_ACPI_TABLE_SIZE (128 * 1024)
 90
 91CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
 92
 93static struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
 94	&acpi_table_attr_aml,
 95	NULL,
 96};
 97
 98static ssize_t acpi_table_signature_show(struct config_item *cfg, char *str)
 99{
100	struct acpi_table_header *h = get_header(cfg);
101
102	if (!h)
103		return -EINVAL;
104
105	return sprintf(str, "%.*s\n", ACPI_NAMESEG_SIZE, h->signature);
106}
107
108static ssize_t acpi_table_length_show(struct config_item *cfg, char *str)
109{
110	struct acpi_table_header *h = get_header(cfg);
111
112	if (!h)
113		return -EINVAL;
114
115	return sprintf(str, "%d\n", h->length);
116}
117
118static ssize_t acpi_table_revision_show(struct config_item *cfg, char *str)
119{
120	struct acpi_table_header *h = get_header(cfg);
121
122	if (!h)
123		return -EINVAL;
124
125	return sprintf(str, "%d\n", h->revision);
126}
127
128static ssize_t acpi_table_oem_id_show(struct config_item *cfg, char *str)
129{
130	struct acpi_table_header *h = get_header(cfg);
131
132	if (!h)
133		return -EINVAL;
134
135	return sprintf(str, "%.*s\n", ACPI_OEM_ID_SIZE, h->oem_id);
136}
137
138static ssize_t acpi_table_oem_table_id_show(struct config_item *cfg, char *str)
139{
140	struct acpi_table_header *h = get_header(cfg);
141
142	if (!h)
143		return -EINVAL;
144
145	return sprintf(str, "%.*s\n", ACPI_OEM_TABLE_ID_SIZE, h->oem_table_id);
146}
147
148static ssize_t acpi_table_oem_revision_show(struct config_item *cfg, char *str)
149{
150	struct acpi_table_header *h = get_header(cfg);
151
152	if (!h)
153		return -EINVAL;
154
155	return sprintf(str, "%d\n", h->oem_revision);
156}
157
158static ssize_t acpi_table_asl_compiler_id_show(struct config_item *cfg,
159					       char *str)
160{
161	struct acpi_table_header *h = get_header(cfg);
162
163	if (!h)
164		return -EINVAL;
165
166	return sprintf(str, "%.*s\n", ACPI_NAMESEG_SIZE, h->asl_compiler_id);
167}
168
169static ssize_t acpi_table_asl_compiler_revision_show(struct config_item *cfg,
170						     char *str)
171{
172	struct acpi_table_header *h = get_header(cfg);
173
174	if (!h)
175		return -EINVAL;
176
177	return sprintf(str, "%d\n", h->asl_compiler_revision);
178}
179
180CONFIGFS_ATTR_RO(acpi_table_, signature);
181CONFIGFS_ATTR_RO(acpi_table_, length);
182CONFIGFS_ATTR_RO(acpi_table_, revision);
183CONFIGFS_ATTR_RO(acpi_table_, oem_id);
184CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
185CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
186CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
187CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);
188
189static struct configfs_attribute *acpi_table_attrs[] = {
190	&acpi_table_attr_signature,
191	&acpi_table_attr_length,
192	&acpi_table_attr_revision,
193	&acpi_table_attr_oem_id,
194	&acpi_table_attr_oem_table_id,
195	&acpi_table_attr_oem_revision,
196	&acpi_table_attr_asl_compiler_id,
197	&acpi_table_attr_asl_compiler_revision,
198	NULL,
199};
200
201static const struct config_item_type acpi_table_type = {
202	.ct_owner = THIS_MODULE,
203	.ct_bin_attrs = acpi_table_bin_attrs,
204	.ct_attrs = acpi_table_attrs,
205};
206
207static struct config_item *acpi_table_make_item(struct config_group *group,
208						const char *name)
209{
210	struct acpi_table *table;
211
212	table = kzalloc(sizeof(*table), GFP_KERNEL);
213	if (!table)
214		return ERR_PTR(-ENOMEM);
215
216	config_item_init_type_name(&table->cfg, name, &acpi_table_type);
217	return &table->cfg;
218}
219
220static void acpi_table_drop_item(struct config_group *group,
221				 struct config_item *cfg)
222{
223	struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
224
225	ACPI_INFO(("Host-directed Dynamic ACPI Table Unload"));
226	acpi_tb_unload_table(table->index);
227}
228
229static struct configfs_group_operations acpi_table_group_ops = {
230	.make_item = acpi_table_make_item,
231	.drop_item = acpi_table_drop_item,
232};
233
234static const struct config_item_type acpi_tables_type = {
235	.ct_owner = THIS_MODULE,
236	.ct_group_ops = &acpi_table_group_ops,
237};
238
239static const struct config_item_type acpi_root_group_type = {
240	.ct_owner = THIS_MODULE,
241};
242
243static struct configfs_subsystem acpi_configfs = {
244	.su_group = {
245		.cg_item = {
246			.ci_namebuf = "acpi",
247			.ci_type = &acpi_root_group_type,
248		},
249	},
250	.su_mutex = __MUTEX_INITIALIZER(acpi_configfs.su_mutex),
251};
252
253static int __init acpi_configfs_init(void)
254{
255	int ret;
256	struct config_group *root = &acpi_configfs.su_group;
257
258	config_group_init(root);
259
260	ret = configfs_register_subsystem(&acpi_configfs);
261	if (ret)
262		return ret;
263
264	acpi_table_group = configfs_register_default_group(root, "table",
265							   &acpi_tables_type);
266	return PTR_ERR_OR_ZERO(acpi_table_group);
267}
268module_init(acpi_configfs_init);
269
270static void __exit acpi_configfs_exit(void)
271{
272	configfs_unregister_default_group(acpi_table_group);
273	configfs_unregister_subsystem(&acpi_configfs);
274}
275module_exit(acpi_configfs_exit);
276
277MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
278MODULE_DESCRIPTION("ACPI configfs support");
279MODULE_LICENSE("GPL v2");