ACPI: introduce sysfs I/F for dynamic tables

SSDT tables may be loaded at runtime.
create sysfs I/F for these dynamic tables in
/sys/firmware/acpi/tables/dynamic/.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 48 insertions, 3 deletions

diff --git a/drivers/acpi/system.c b/drivers/acpi/system.c
index 391d0358a592..c8859047acfe 100644
--- a/drivers/acpi/system.c
+++ b/drivers/acpi/system.c
@@ -62,6 +62,7 @@ module_param_call(acpica_version, NULL, param_get_acpica_version, NULL, 0444);
    -------------------------------------------------------------------------- */
 static LIST_HEAD(acpi_table_attr_list);
 static struct kobject *tables_kobj;
+static struct kobject *dynamic_tables_kobj;
 
 struct acpi_table_attr {
         struct bin_attribute attr;
@@ -128,6 +129,40 @@ static void acpi_table_attr_init(struct acpi_table_attr *table_attr,
         return;
 }
 
+static acpi_status
+acpi_sysfs_table_handler(u32 event, void *table, void *context)
+{
+        struct acpi_table_attr *table_attr;
+
+        switch (event) {
+        case ACPI_TABLE_EVENT_LOAD:
+                table_attr =
+                        kzalloc(sizeof(struct acpi_table_attr), GFP_KERNEL);
+                if (!table_attr)
+                        return AE_NO_MEMORY;
+
+                acpi_table_attr_init(table_attr, table);
+                if (sysfs_create_bin_file(dynamic_tables_kobj,
+                                        &table_attr->attr)) {
+                        kfree(table_attr);
+                        return AE_ERROR;
+                } else
+                        list_add_tail(&table_attr->node,
+                                        &acpi_table_attr_list);
+                break;
+        case ACPI_TABLE_EVENT_UNLOAD:
+                /*
+                 * we do not need to do anything right now
+                 * because the table is not deleted from the
+                 * global table list when unloading it.
+                 */
+                break;
+        default:
+                return AE_BAD_PARAMETER;
+        }
+        return AE_OK;
+}
+
 static int acpi_system_sysfs_init(void)
 {
         struct acpi_table_attr *table_attr;
@@ -137,7 +172,11 @@ static int acpi_system_sysfs_init(void)
 
         tables_kobj = kobject_create_and_add("tables", acpi_kobj);
         if (!tables_kobj)
-                return -ENOMEM;
+                goto err;
+
+        dynamic_tables_kobj = kobject_create_and_add("dynamic", tables_kobj);
+        if (!dynamic_tables_kobj)
+                goto err_dynamic_tables;
 
         do {
                 result = acpi_get_table_by_index(table_index, &table_header);
@@ -162,8 +201,14 @@ static int acpi_system_sysfs_init(void)
                 }
         } while (!result);
         kobject_uevent(tables_kobj, KOBJ_ADD);
-
-        return 0;
+        kobject_uevent(dynamic_tables_kobj, KOBJ_ADD);
+        result = acpi_install_table_handler(acpi_sysfs_table_handler, NULL);
+
+        return result == AE_OK ? 0 : -EINVAL;
+err_dynamic_tables:
+        kobject_put(tables_kobj);
+err:
+        return -ENOMEM;
 }
 
 /*