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>

3 files changed, 69 insertions, 1 deletions

diff --git a/hw/core/Makefile.objs b/hw/core/Makefile.objs
index 981593c..5377d05 100644
--- a/hw/core/Makefile.objs
+++ b/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
diff --git a/hw/core/fw-path-provider.c b/hw/core/fw-path-provider.c
new file mode 100644
index 0000000..b117157
--- /dev/null
+++ b/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)
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 9f0a522..cd09cd4 100644
--- a/hw/core/qdev.c
+++ b/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);