4 files changed, 132 insertions, 9 deletions

diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c
index bea7223d7a71..f0edf5c43c03 100644
--- a/drivers/acpi/acpica/evregion.c
+++ b/drivers/acpi/acpica/evregion.c
@@ -55,6 +55,8 @@ static u8
 acpi_ev_has_default_handler(struct acpi_namespace_node *node,
                             acpi_adr_space_type space_id);
 
+static void acpi_ev_orphan_ec_reg_method(void);
+
 static acpi_status
 acpi_ev_reg_run(acpi_handle obj_handle,
                 u32 level, void *context, void **return_value);
@@ -561,7 +563,9 @@ acpi_ev_detach_region(union acpi_operand_object *region_obj,
 
                         /* Now stop region accesses by executing the _REG method */
 
-                        status = acpi_ev_execute_reg_method(region_obj, 0);
+                        status =
+                            acpi_ev_execute_reg_method(region_obj,
+                                                       ACPI_REG_DISCONNECT);
                         if (ACPI_FAILURE(status)) {
                                 ACPI_EXCEPTION((AE_INFO, status,
                                                 "from region _REG, [%s]",
@@ -1062,6 +1066,12 @@ acpi_ev_execute_reg_methods(struct acpi_namespace_node *node,
                                         ACPI_NS_WALK_UNLOCK, acpi_ev_reg_run,
                                         NULL, &space_id, NULL);
 
+        /* Special case for EC: handle "orphan" _REG methods with no region */
+
+        if (space_id == ACPI_ADR_SPACE_EC) {
+                acpi_ev_orphan_ec_reg_method();
+        }
+
         return_ACPI_STATUS(status);
 }
 
@@ -1120,6 +1130,113 @@ acpi_ev_reg_run(acpi_handle obj_handle,
                 return (AE_OK);
         }
 
-        status = acpi_ev_execute_reg_method(obj_desc, 1);
+        status = acpi_ev_execute_reg_method(obj_desc, ACPI_REG_CONNECT);
         return (status);
 }
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_orphan_ec_reg_method
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Execute an "orphan" _REG method that appears under the EC
+ *              device. This is a _REG method that has no corresponding region
+ *              within the EC device scope. The orphan _REG method appears to
+ *              have been enabled by the description of the ECDT in the ACPI
+ *              specification: "The availability of the region space can be
+ *              detected by providing a _REG method object underneath the
+ *              Embedded Controller device."
+ *
+ *              To quickly access the EC device, we use the EC_ID that appears
+ *              within the ECDT. Otherwise, we would need to perform a time-
+ *              consuming namespace walk, executing _HID methods to find the
+ *              EC device.
+ *
+ ******************************************************************************/
+
+static void acpi_ev_orphan_ec_reg_method(void)
+{
+        struct acpi_table_ecdt *table;
+        acpi_status status;
+        struct acpi_object_list args;
+        union acpi_object objects[2];
+        struct acpi_namespace_node *ec_device_node;
+        struct acpi_namespace_node *reg_method;
+        struct acpi_namespace_node *next_node;
+
+        ACPI_FUNCTION_TRACE(ev_orphan_ec_reg_method);
+
+        /* Get the ECDT (if present in system) */
+
+        status = acpi_get_table(ACPI_SIG_ECDT, 0,
+                                ACPI_CAST_INDIRECT_PTR(struct acpi_table_header,
+                                                       &table));
+        if (ACPI_FAILURE(status)) {
+                return_VOID;
+        }
+
+        /* We need a valid EC_ID string */
+
+        if (!(*table->id)) {
+                return_VOID;
+        }
+
+        /* Namespace is currently locked, must release */
+
+        (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+
+        /* Get a handle to the EC device referenced in the ECDT */
+
+        status = acpi_get_handle(NULL,
+                                 ACPI_CAST_PTR(char, table->id),
+                                 ACPI_CAST_PTR(acpi_handle, &ec_device_node));
+        if (ACPI_FAILURE(status)) {
+                goto exit;
+        }
+
+        /* Get a handle to a _REG method immediately under the EC device */
+
+        status = acpi_get_handle(ec_device_node,
+                                 METHOD_NAME__REG, ACPI_CAST_PTR(acpi_handle,
+                                                                 &reg_method));
+        if (ACPI_FAILURE(status)) {
+                goto exit;
+        }
+
+        /*
+         * Execute the _REG method only if there is no Operation Region in
+         * this scope with the Embedded Controller space ID. Otherwise, it
+         * will already have been executed. Note, this allows for Regions
+         * with other space IDs to be present; but the code below will then
+         * execute the _REG method with the EC space ID argument.
+         */
+        next_node = acpi_ns_get_next_node(ec_device_node, NULL);
+        while (next_node) {
+                if ((next_node->type == ACPI_TYPE_REGION) &&
+                    (next_node->object) &&
+                    (next_node->object->region.space_id == ACPI_ADR_SPACE_EC)) {
+                        goto exit;      /* Do not execute _REG */
+                }
+                next_node = acpi_ns_get_next_node(ec_device_node, next_node);
+        }
+
+        /* Evaluate the _REG(EC,Connect) method */
+
+        args.count = 2;
+        args.pointer = objects;
+        objects[0].type = ACPI_TYPE_INTEGER;
+        objects[0].integer.value = ACPI_ADR_SPACE_EC;
+        objects[1].type = ACPI_TYPE_INTEGER;
+        objects[1].integer.value = ACPI_REG_CONNECT;
+
+        status = acpi_evaluate_object(reg_method, NULL, &args, NULL);
+
+      exit:
+        /* We ignore all errors from above, don't care */
+
+        status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+        return_VOID;
+}
diff --git a/drivers/acpi/acpica/evrgnini.c b/drivers/acpi/acpica/evrgnini.c
index 9659cee6093e..55a5d35ef34a 100644
--- a/drivers/acpi/acpica/evrgnini.c
+++ b/drivers/acpi/acpica/evrgnini.c
@@ -637,7 +637,7 @@ acpi_ev_initialize_region(union acpi_operand_object *region_obj,
 
                                         status =
                                             acpi_ev_execute_reg_method
-                                            (region_obj, 1);
+                                            (region_obj, ACPI_REG_CONNECT);
 
                                         if (acpi_ns_locked) {
                                                 status =
diff --git a/drivers/acpi/acpica/evxfregn.c b/drivers/acpi/acpica/evxfregn.c
index c85c8c45599d..00cd95692a91 100644
--- a/drivers/acpi/acpica/evxfregn.c
+++ b/drivers/acpi/acpica/evxfregn.c
@@ -130,20 +130,21 @@ acpi_install_address_space_handler(acpi_handle device,
         case ACPI_ADR_SPACE_PCI_CONFIG:
         case ACPI_ADR_SPACE_DATA_TABLE:
 
-                if (acpi_gbl_reg_methods_executed) {
+                if (!acpi_gbl_reg_methods_executed) {
 
-                        /* Run all _REG methods for this address space */
-
-                        status = acpi_ev_execute_reg_methods(node, space_id);
+                        /* We will defer execution of the _REG methods for this space */
+                        goto unlock_and_exit;
                 }
                 break;
 
         default:
-
-                status = acpi_ev_execute_reg_methods(node, space_id);
                 break;
         }
 
+        /* Run all _REG methods for this address space */
+
+        status = acpi_ev_execute_reg_methods(node, space_id);
+
       unlock_and_exit:
         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
         return_ACPI_STATUS(status);
diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
index f3b29fa5654e..a6412b82a572 100644
--- a/include/acpi/actypes.h
+++ b/include/acpi/actypes.h
@@ -726,6 +726,11 @@ typedef u8 acpi_adr_space_type;
 #define ACPI_ADR_SPACE_DATA_TABLE       (acpi_adr_space_type) 0x7E      /* Internal to ACPICA only */
 #define ACPI_ADR_SPACE_FIXED_HARDWARE   (acpi_adr_space_type) 0x7F
 
+/* Values for _REG connection code */
+
+#define ACPI_REG_DISCONNECT             0
+#define ACPI_REG_CONNECT                1
+
 /*
  * bit_register IDs
  *