3 files changed, 95 insertions, 52 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index c8926c1acd22..46c526eb1bab 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -316,6 +316,14 @@ W:	https://01.org/linux-acpi
 S:      Supported
 F:      drivers/acpi/fan.c
 
+ACPI FOR ARM64 (ACPI/arm64)
+M:      Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+M:      Hanjun Guo <hanjun.guo@linaro.org>
+M:      Sudeep Holla <sudeep.holla@arm.com>
+L:      linux-acpi@vger.kernel.org
+S:      Maintained
+F:      drivers/acpi/arm64
+
 ACPI THERMAL DRIVER
 M:      Zhang Rui <rui.zhang@intel.com>
 L:      linux-acpi@vger.kernel.org
diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index f2fd3fee588a..03f5ec11ab31 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -468,10 +468,11 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
 }
 
 /**
- * acpi_data_get_property_reference - returns handle to the referenced object
- * @data: ACPI device data object containing the property
+ * __acpi_node_get_property_reference - returns handle to the referenced object
+ * @fwnode: Firmware node to get the property from
  * @propname: Name of the property
  * @index: Index of the reference to return
+ * @num_args: Maximum number of arguments after each reference
  * @args: Location to store the returned reference with optional arguments
  *
  * Find property with @name, verifify that it is a package containing at least
@@ -482,17 +483,40 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
  * If there's more than one reference in the property value package, @index is
  * used to select the one to return.
  *
+ * It is possible to leave holes in the property value set like in the
+ * example below:
+ *
+ * Package () {
+ *     "cs-gpios",
+ *     Package () {
+ *        ^GPIO, 19, 0, 0,
+ *        ^GPIO, 20, 0, 0,
+ *        0,
+ *        ^GPIO, 21, 0, 0,
+ *     }
+ * }
+ *
+ * Calling this function with index %2 return %-ENOENT and with index %3
+ * returns the last entry. If the property does not contain any more values
+ * %-ENODATA is returned. The NULL entry must be single integer and
+ * preferably contain value %0.
+ *
  * Return: %0 on success, negative error code on failure.
  */
-static int acpi_data_get_property_reference(struct acpi_device_data *data,
-                                            const char *propname, size_t index,
-                                            struct acpi_reference_args *args)
+int __acpi_node_get_property_reference(struct fwnode_handle *fwnode,
+        const char *propname, size_t index, size_t num_args,
+        struct acpi_reference_args *args)
 {
         const union acpi_object *element, *end;
         const union acpi_object *obj;
+        struct acpi_device_data *data;
         struct acpi_device *device;
         int ret, idx = 0;
 
+        data = acpi_device_data_of_node(fwnode);
+        if (!data)
+                return -EINVAL;
+
         ret = acpi_data_get_property(data, propname, ACPI_TYPE_ANY, &obj);
         if (ret)
                 return ret;
@@ -532,59 +556,54 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
         while (element < end) {
                 u32 nargs, i;
 
-                if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
-                        return -EPROTO;
-
-                ret = acpi_bus_get_device(element->reference.handle, &device);
-                if (ret)
-                        return -ENODEV;
-
-                element++;
-                nargs = 0;
-
-                /* assume following integer elements are all args */
-                for (i = 0; element + i < end; i++) {
-                        int type = element[i].type;
+                if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
+                        ret = acpi_bus_get_device(element->reference.handle,
+                                                  &device);
+                        if (ret)
+                                return -ENODEV;
+
+                        nargs = 0;
+                        element++;
+
+                        /* assume following integer elements are all args */
+                        for (i = 0; element + i < end && i < num_args; i++) {
+                                int type = element[i].type;
+
+                                if (type == ACPI_TYPE_INTEGER)
+                                        nargs++;
+                                else if (type == ACPI_TYPE_LOCAL_REFERENCE)
+                                        break;
+                                else
+                                        return -EPROTO;
+                        }
 
-                        if (type == ACPI_TYPE_INTEGER)
-                                nargs++;
-                        else if (type == ACPI_TYPE_LOCAL_REFERENCE)
-                                break;
-                        else
+                        if (nargs > MAX_ACPI_REFERENCE_ARGS)
                                 return -EPROTO;
-                }
 
-                if (idx++ == index) {
-                        args->adev = device;
-                        args->nargs = nargs;
-                        for (i = 0; i < nargs; i++)
-                                args->args[i] = element[i].integer.value;
+                        if (idx == index) {
+                                args->adev = device;
+                                args->nargs = nargs;
+                                for (i = 0; i < nargs; i++)
+                                        args->args[i] = element[i].integer.value;
 
-                        return 0;
+                                return 0;
+                        }
+
+                        element += nargs;
+                } else if (element->type == ACPI_TYPE_INTEGER) {
+                        if (idx == index)
+                                return -ENOENT;
+                        element++;
+                } else {
+                        return -EPROTO;
                 }
 
-                element += nargs;
+                idx++;
         }
 
-        return -EPROTO;
-}
-
-/**
- * acpi_node_get_property_reference - get a handle to the referenced object.
- * @fwnode: Firmware node to get the property from.
- * @propname: Name of the property.
- * @index: Index of the reference to return.
- * @args: Location to store the returned reference with optional arguments.
- */
-int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
-                                     const char *name, size_t index,
-                                     struct acpi_reference_args *args)
-{
-        struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
-
-        return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
+        return -ENODATA;
 }
-EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);
+EXPORT_SYMBOL_GPL(__acpi_node_get_property_reference);
 
 static int acpi_data_prop_read_single(struct acpi_device_data *data,
                                       const char *propname,
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 65932c08afd2..2d42fb7d56b7 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -934,9 +934,17 @@ struct acpi_reference_args {
 #ifdef CONFIG_ACPI
 int acpi_dev_get_property(struct acpi_device *adev, const char *name,
                           acpi_object_type type, const union acpi_object **obj);
-int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
-                                     const char *name, size_t index,
-                                     struct acpi_reference_args *args);
+int __acpi_node_get_property_reference(struct fwnode_handle *fwnode,
+                                const char *name, size_t index, size_t num_args,
+                                struct acpi_reference_args *args);
+
+static inline int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
+                                const char *name, size_t index,
+                                struct acpi_reference_args *args)
+{
+        return __acpi_node_get_property_reference(fwnode, name, index,
+                MAX_ACPI_REFERENCE_ARGS, args);
+}
 
 int acpi_node_prop_get(struct fwnode_handle *fwnode, const char *propname,
                        void **valptr);
@@ -1012,6 +1020,14 @@ static inline int acpi_dev_get_property(struct acpi_device *adev,
         return -ENXIO;
 }
 
+static inline int
+__acpi_node_get_property_reference(struct fwnode_handle *fwnode,
+                                const char *name, size_t index, size_t num_args,
+                                struct acpi_reference_args *args)
+{
+        return -ENXIO;
+}
+
 static inline int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
                                 const char *name, size_t index,
                                 struct acpi_reference_args *args)