qdev: Introduce FWPathProvider interface

QEMU supports firmware names for all devices in the QEMU tree but
some architectures expect some parts of firmware path names in different
format.

This introduces a firmware-pathname-change interface definition.
If some machines needs to redefine the firmware path format, it has
to add the TYPE_FW_PATH_PROVIDER interface to an object that is above
the device on the QOM tree (typically /machine).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Andreas Färber <afaerber@suse.de>

hw/core/Makefile.objs

@@ -1,5 +1,6 @@
 # core qdev-related obj files, also used by *-user:
 common-obj-y += qdev.o qdev-properties.o
+common-obj-y += fw-path-provider.o
 # irq.o needed for qdev GPIO handling:
 common-obj-y += irq.o
 common-obj-y += hotplug.o

hw/core/fw-path-provider.c

@@ -0,0 +1,51 @@
+/*
+ *  Firmware patch provider class and helpers.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "hw/fw-path-provider.h"
+
+char *fw_path_provider_get_dev_path(FWPathProvider *p, BusState *bus,
+                                    DeviceState *dev)
+{
+    FWPathProviderClass *k = FW_PATH_PROVIDER_GET_CLASS(p);
+
+    return k->get_dev_path(p, bus, dev);
+}
+
+char *fw_path_provider_try_get_dev_path(Object *o, BusState *bus,
+                                        DeviceState *dev)
+{
+    FWPathProvider *p = (FWPathProvider *)
+        object_dynamic_cast(o, TYPE_FW_PATH_PROVIDER);
+
+    if (p) {
+        return fw_path_provider_get_dev_path(p, bus, dev);
+    }
+
+    return NULL;
+}
+
+static const TypeInfo fw_path_provider_info = {
+    .name          = TYPE_FW_PATH_PROVIDER,
+    .parent        = TYPE_INTERFACE,
+    .class_size    = sizeof(FWPathProviderClass),
+};
+
+static void fw_path_provider_register_types(void)
+{
+    type_register_static(&fw_path_provider_info);
+}
+
+type_init(fw_path_provider_register_types)

hw/core/qdev.c

@@ -26,6 +26,7 @@
    this API directly.  */
 
 #include "hw/qdev.h"
+#include "hw/fw-path-provider.h"
 #include "sysemu/sysemu.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qerror.h"
@@ -568,6 +569,18 @@ static char *bus_get_fw_dev_path(BusState *bus, DeviceState *dev)
     return NULL;
 }
 
+static char *qdev_get_fw_dev_path_from_handler(BusState *bus, DeviceState *dev)
+{
+    Object *obj = OBJECT(dev);
+    char *d = NULL;
+
+    while (!d && obj->parent) {
+        obj = obj->parent;
+        d = fw_path_provider_try_get_dev_path(obj, bus, dev);
+    }
+    return d;
+}
+
 static int qdev_get_fw_dev_path_helper(DeviceState *dev, char *p, int size)
 {
     int l = 0;
@@ -575,7 +588,10 @@ static int qdev_get_fw_dev_path_helper(DeviceState *dev, char *p, int size)
     if (dev && dev->parent_bus) {
         char *d;
         l = qdev_get_fw_dev_path_helper(dev->parent_bus->parent, p, size);
-        d = bus_get_fw_dev_path(dev->parent_bus, dev);
+        d = qdev_get_fw_dev_path_from_handler(dev->parent_bus, dev);
+        if (!d) {
+            d = bus_get_fw_dev_path(dev->parent_bus, dev);
+        }
         if (d) {
             l += snprintf(p + l, size - l, "%s", d);
             g_free(d);

include/hw/fw-path-provider.h

@@ -0,0 +1,47 @@
+/*
+ *  Firmware patch provider class and helpers definitions.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef FW_PATH_PROVIDER_H
+#define FW_PATH_PROVIDER_H 1
+
+#include "qemu-common.h"
+#include "qom/object.h"
+
+#define TYPE_FW_PATH_PROVIDER "fw-path-provider"
+
+#define FW_PATH_PROVIDER_CLASS(klass) \
+     OBJECT_CLASS_CHECK(FWPathProviderClass, (klass), TYPE_FW_PATH_PROVIDER)
+#define FW_PATH_PROVIDER_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(FWPathProviderClass, (obj), TYPE_FW_PATH_PROVIDER)
+#define FW_PATH_PROVIDER(obj) \
+     INTERFACE_CHECK(FWPathProvider, (obj), TYPE_FW_PATH_PROVIDER)
+
+typedef struct FWPathProvider {
+    Object parent_obj;
+} FWPathProvider;
+
+typedef struct FWPathProviderClass {
+    InterfaceClass parent_class;
+
+    char *(*get_dev_path)(FWPathProvider *p, BusState *bus, DeviceState *dev);
+} FWPathProviderClass;
+
+char *fw_path_provider_get_dev_path(FWPathProvider *p, BusState *bus,
+                                    DeviceState *dev);
+char *fw_path_provider_try_get_dev_path(Object *o, BusState *bus,
+                                        DeviceState *dev);
+
+#endif /* FW_PATH_PROVIDER_H */

tests/Makefile

@@ -206,6 +206,7 @@ tests/test-int128$(EXESUF): tests/test-int128.o
 tests/test-qdev-global-props$(EXESUF): tests/test-qdev-global-props.o \
 	hw/core/qdev.o hw/core/qdev-properties.o hw/core/hotplug.o\
 	hw/core/irq.o \
+	hw/core/fw-path-provider.o \
 	$(qom-core-obj) \
 	$(test-qapi-obj-y) \
 	libqemuutil.a libqemustub.a