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![Jan Kiszka](/assets/img/avatar_default.png)
Call directly into acpica to load a table to obtain its index on return. We choose the direct call of acpica internal functions to avoid having to modify its API which is used outside of Linux as well. Use that index to unload the table again when the corresponding directory in configfs gets removed. This allows to change SSDTs without rebooting the system. It also allows to destroy devices again that a dynamically loaded SSDT created. This is widely similar to the DT overlay behavior. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
285 lines
6.4 KiB
C
285 lines
6.4 KiB
C
/*
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* ACPI configfs support
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*
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* Copyright (c) 2016 Intel Corporation
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#define pr_fmt(fmt) "ACPI configfs: " fmt
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/configfs.h>
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#include <linux/acpi.h>
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#include "acpica/accommon.h"
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#include "acpica/actables.h"
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static struct config_group *acpi_table_group;
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struct acpi_table {
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struct config_item cfg;
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struct acpi_table_header *header;
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u32 index;
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};
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static ssize_t acpi_table_aml_write(struct config_item *cfg,
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const void *data, size_t size)
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{
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const struct acpi_table_header *header = data;
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struct acpi_table *table;
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int ret;
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table = container_of(cfg, struct acpi_table, cfg);
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if (table->header) {
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pr_err("table already loaded\n");
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return -EBUSY;
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}
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if (header->length != size) {
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pr_err("invalid table length\n");
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return -EINVAL;
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}
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if (memcmp(header->signature, ACPI_SIG_SSDT, 4)) {
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pr_err("invalid table signature\n");
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return -EINVAL;
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}
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table = container_of(cfg, struct acpi_table, cfg);
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table->header = kmemdup(header, header->length, GFP_KERNEL);
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if (!table->header)
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return -ENOMEM;
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ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
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ret = acpi_tb_install_and_load_table(
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ACPI_PTR_TO_PHYSADDR(table->header),
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ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE,
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&table->index);
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if (ret) {
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kfree(table->header);
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table->header = NULL;
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}
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return ret;
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}
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static inline struct acpi_table_header *get_header(struct config_item *cfg)
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{
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struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
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if (!table->header)
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pr_err("table not loaded\n");
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return table->header;
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}
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static ssize_t acpi_table_aml_read(struct config_item *cfg,
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void *data, size_t size)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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if (data)
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memcpy(data, h, h->length);
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return h->length;
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}
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#define MAX_ACPI_TABLE_SIZE (128 * 1024)
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CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
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struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
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&acpi_table_attr_aml,
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NULL,
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};
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ssize_t acpi_table_signature_show(struct config_item *cfg, char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->signature);
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}
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ssize_t acpi_table_length_show(struct config_item *cfg, char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%d\n", h->length);
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}
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ssize_t acpi_table_revision_show(struct config_item *cfg, char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%d\n", h->revision);
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}
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ssize_t acpi_table_oem_id_show(struct config_item *cfg, char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%.*s\n", ACPI_OEM_ID_SIZE, h->oem_id);
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}
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ssize_t acpi_table_oem_table_id_show(struct config_item *cfg, char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%.*s\n", ACPI_OEM_TABLE_ID_SIZE, h->oem_table_id);
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}
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ssize_t acpi_table_oem_revision_show(struct config_item *cfg, char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%d\n", h->oem_revision);
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}
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ssize_t acpi_table_asl_compiler_id_show(struct config_item *cfg, char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->asl_compiler_id);
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}
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ssize_t acpi_table_asl_compiler_revision_show(struct config_item *cfg,
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char *str)
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{
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struct acpi_table_header *h = get_header(cfg);
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if (!h)
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return -EINVAL;
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return sprintf(str, "%d\n", h->asl_compiler_revision);
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}
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CONFIGFS_ATTR_RO(acpi_table_, signature);
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CONFIGFS_ATTR_RO(acpi_table_, length);
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CONFIGFS_ATTR_RO(acpi_table_, revision);
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CONFIGFS_ATTR_RO(acpi_table_, oem_id);
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CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
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CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
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CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
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CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);
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struct configfs_attribute *acpi_table_attrs[] = {
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&acpi_table_attr_signature,
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&acpi_table_attr_length,
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&acpi_table_attr_revision,
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&acpi_table_attr_oem_id,
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&acpi_table_attr_oem_table_id,
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&acpi_table_attr_oem_revision,
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&acpi_table_attr_asl_compiler_id,
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&acpi_table_attr_asl_compiler_revision,
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NULL,
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};
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static struct config_item_type acpi_table_type = {
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.ct_owner = THIS_MODULE,
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.ct_bin_attrs = acpi_table_bin_attrs,
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.ct_attrs = acpi_table_attrs,
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};
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static struct config_item *acpi_table_make_item(struct config_group *group,
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const char *name)
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{
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struct acpi_table *table;
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table = kzalloc(sizeof(*table), GFP_KERNEL);
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if (!table)
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return ERR_PTR(-ENOMEM);
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config_item_init_type_name(&table->cfg, name, &acpi_table_type);
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return &table->cfg;
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}
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static void acpi_table_drop_item(struct config_group *group,
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struct config_item *cfg)
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{
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struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
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ACPI_INFO(("Host-directed Dynamic ACPI Table Unload"));
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acpi_tb_unload_table(table->index);
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}
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struct configfs_group_operations acpi_table_group_ops = {
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.make_item = acpi_table_make_item,
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.drop_item = acpi_table_drop_item,
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};
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static struct config_item_type acpi_tables_type = {
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.ct_owner = THIS_MODULE,
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.ct_group_ops = &acpi_table_group_ops,
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};
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static struct config_item_type acpi_root_group_type = {
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.ct_owner = THIS_MODULE,
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};
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static struct configfs_subsystem acpi_configfs = {
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.su_group = {
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.cg_item = {
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.ci_namebuf = "acpi",
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.ci_type = &acpi_root_group_type,
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},
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},
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.su_mutex = __MUTEX_INITIALIZER(acpi_configfs.su_mutex),
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};
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static int __init acpi_configfs_init(void)
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{
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int ret;
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struct config_group *root = &acpi_configfs.su_group;
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config_group_init(root);
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ret = configfs_register_subsystem(&acpi_configfs);
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if (ret)
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return ret;
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acpi_table_group = configfs_register_default_group(root, "table",
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&acpi_tables_type);
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return PTR_ERR_OR_ZERO(acpi_table_group);
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}
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module_init(acpi_configfs_init);
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static void __exit acpi_configfs_exit(void)
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{
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configfs_unregister_default_group(acpi_table_group);
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configfs_unregister_subsystem(&acpi_configfs);
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}
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module_exit(acpi_configfs_exit);
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MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
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MODULE_DESCRIPTION("ACPI configfs support");
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MODULE_LICENSE("GPL v2");
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