[Qemu-devel] [PATCH v4 04/23] qdev: Allow device addressing via 'driver.instance'

[Jan Kiszka]

From: Jan Kiszka <address@hidden>

Extend qbus_find_dev to allow addressing of devices without an unique id
via an optional per-bus instance number. The new formats are
'driver.instance' and 'alias.instance'. Attach this name extension
whenever an instantiated device is printed.

Signed-off-by: Jan Kiszka <address@hidden>
---
 docs/qdev-device-use.txt |   13 +++++++++++-
 hw/qdev.c                |   48 +++++++++++++++++++++++++++++++++++++--------
 2 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/docs/qdev-device-use.txt b/docs/qdev-device-use.txt
index f252c8e..58f2630 100644
--- a/docs/qdev-device-use.txt
+++ b/docs/qdev-device-use.txt
@@ -1,6 +1,6 @@
 = How to convert to -device & friends =
 
-=== Specifying Bus and Address on Bus ===
+=== Specifying Bus, Address on Bus, and Devices ===
 
 In qdev, each device has a parent bus.  Some devices provide one or
 more buses for children.  You can specify a device's parent bus with
@@ -20,6 +20,17 @@ bus named pci.0.  To put a FOO device into its slot 4, use 
-device
 FOO,bus=/i440FX-pcihost/pci.0,addr=4.  The abbreviated form bus=pci.0
 also works as long as the bus name is unique.
 
+Existing devices can be addressed either via a unique ID if it was
+assigned during creation or via the device tree path:
+
+/full_bus_address/driver_name[.instance_number]
+
+The instance number counts devices managed by the same driver on a
+specifc bus. It is zero-based.
+
+Example: /i440FX-pcihost/pci.0/e1000.1 addresses the second e1000
+adapter on the bus 'pci.0'.
+
 Note: the USB device address can't be controlled at this time.
 
 === Block Devices ===
diff --git a/hw/qdev.c b/hw/qdev.c
index aa25155..f4ae4a6 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -492,12 +492,29 @@ static DeviceState *qdev_find_recursive(BusState *bus, 
const char *id)
     return NULL;
 }
 
+static int qdev_instance_no(DeviceState *dev)
+{
+    struct DeviceState *sibling;
+    int instance = 0;
+
+    QLIST_FOREACH(sibling, &dev->parent_bus->children, sibling) {
+        if (sibling->info == dev->info) {
+            if (sibling == dev) {
+                break;
+            }
+            instance++;
+        }
+    }
+    return instance;
+}
+
 static void qbus_list_bus(DeviceState *dev)
 {
     BusState *child;
     const char *sep = " ";
 
-    error_printf("child busses at \"%s\":", dev->info->name);
+    error_printf("child busses at \"%s.%d\":",
+                 dev->info->name, qdev_instance_no(dev));
     QLIST_FOREACH(child, &dev->child_bus, sibling) {
         error_printf("%s\"%s\"", sep, child->name);
         sep = ", ";
@@ -512,7 +529,8 @@ static void qbus_list_dev(BusState *bus)
 
     error_printf("devices at \"%s\":", bus->name);
     QLIST_FOREACH(dev, &bus->children, sibling) {
-        error_printf("%s\"%s\"", sep, dev->info->name);
+        error_printf("%s\"%s.%d\"", sep, dev->info->name,
+                     qdev_instance_no(dev));
         sep = ", ";
     }
     error_printf("\n");
@@ -530,23 +548,35 @@ static BusState *qbus_find_bus(DeviceState *dev, char 
*elem)
     return NULL;
 }
 
-static DeviceState *qbus_find_dev(BusState *bus, char *elem)
+static DeviceState *qbus_find_dev(BusState *bus, const char *elem)
 {
     DeviceState *dev;
+    int instance, n;
+    char buf[128];
 
     /*
      * try to match in order:
-     *   (1) driver name
-     *   (2) driver alias, if present
+     *   (1) driver name [.instance]
+     *   (2) driver alias [.instance], if present
      */
 
+    if (sscanf(elem, "%127[^.].%u", buf, &instance) == 2) {
+        elem = buf;
+    } else {
+        instance = 0;
+    }
+
+    n = 0;
     QLIST_FOREACH(dev, &bus->children, sibling) {
-        if (strcmp(dev->info->name, elem) == 0) {
+        if (strcmp(dev->info->name, elem) == 0 && n++ == instance) {
             return dev;
         }
     }
+
+    n = 0;
     QLIST_FOREACH(dev, &bus->children, sibling) {
-        if (dev->info->alias && strcmp(dev->info->alias, elem) == 0) {
+        if (dev->info->alias && strcmp(dev->info->alias, elem) == 0 &&
+            n++ == instance) {
             return dev;
         }
     }
@@ -710,8 +740,8 @@ static void qdev_print_props(Monitor *mon, DeviceState 
*dev, Property *props,
 static void qdev_print(Monitor *mon, DeviceState *dev, int indent)
 {
     BusState *child;
-    qdev_printf("dev: %s, id \"%s\"\n", dev->info->name,
-                dev->id ? dev->id : "");
+    qdev_printf("dev: %s.%d, id \"%s\"\n", dev->info->name,
+                qdev_instance_no(dev), dev->id ? dev->id : "");
     indent += 2;
     if (dev->num_gpio_in) {
         qdev_printf("gpio-in %d\n", dev->num_gpio_in);
-- 
1.6.0.2