[Qemu-devel] [PATCH 4/8] qdev/core: bus list

[Gerd Hoffmann <kraxel@redhat.com>]

 * maintain a list of busses.
 * maintain bus numbers.
 * add function to find busses by type / name / number.
 * add monitor command to list busses.

Use case for the bus list is hot-plugging devices via monitor, where
qemu needs some way to find the bus specified in the monitor command.
The usb patches in the patch queue make use of this.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/qdev.c |   41 ++++++++++++++++++++++++++++++++++++++++-
 hw/qdev.h |    5 +++++
 monitor.c |    2 ++
 3 files changed, 47 insertions(+), 1 deletions(-)

diff --git a/hw/qdev.c b/hw/qdev.c
index 3dc7076..1fb73b1 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -306,22 +306,50 @@ void scsi_bus_new(DeviceState *host, SCSIAttachFn attach)
        attach(host, drives_table[index].bdrv, unit);
    }
 }
+static TAILQ_HEAD(, BusState) buslist = TAILQ_HEAD_INITIALIZER(buslist);
 
 BusState *qbus_create(BusInfo *info, DeviceState *parent, const char *name)
 {
     BusState *bus;
+    char buf[32];
+    int i;
 
     bus = qemu_mallocz(info->size);
     bus->info = info;
+    bus->busnr = info->next_busnr++;
     bus->parent = parent;
+    if (!name) {
+        /* default name: lowercase(type) + busnr, i.e. "scsi0" */
+        snprintf(buf, sizeof(buf), "%s%d", info->name, bus->busnr);
+        for (i = 0; buf[i]; i++)
+            buf[i] = tolower(buf[i]);
+        name = buf;
+    }
     bus->name = qemu_strdup(name);
     LIST_INIT(&bus->children);
     if (parent) {
         LIST_INSERT_HEAD(&parent->child_bus, bus, sibling);
     }
+    TAILQ_INSERT_TAIL(&buslist, bus, next);
     return bus;
 }
 
+BusState *qbus_find(const char *type, const char *name, int busnr)
+{
+    BusState *bus;
+
+    TAILQ_FOREACH(bus, &buslist, next) {
+        if (type && strcmp(type, bus->info->name) != 0)
+            continue;
+        if (name && strcmp(name, bus->name) != 0)
+            continue;
+        if (busnr != -1 && busnr != bus->busnr)
+            continue;
+        return bus;
+    }
+    return NULL;
+}
+
 #define qdev_printf(fmt, ...) monitor_printf(mon, "%*s" fmt, indent, "", ## __VA_ARGS__)
 static void qbus_print(Monitor *mon, BusState *bus, int indent);
 
@@ -368,7 +396,7 @@ static void qbus_print(Monitor *mon, BusState *bus, int indent)
 
     qdev_printf("bus: %s\n", bus->name);
     indent += 2;
-    qdev_printf("type %s\n", bus->info->name);
+    qdev_printf("type %s, nr %d\n", bus->info->name, bus->busnr);
     LIST_FOREACH(dev, &bus->children, sibling) {
         qdev_print(mon, dev, indent);
     }
@@ -380,3 +408,14 @@ void do_info_qtree(Monitor *mon)
     if (main_system_bus)
         qbus_print(mon, main_system_bus, 0);
 }
+
+void do_info_qbus(Monitor *mon)
+{
+    BusState *bus;
+
+    TAILQ_FOREACH(bus, &buslist, next) {
+        monitor_printf(mon, "%s: type %s, nr %d, parent %s\n",
+                       bus->name, bus->info->name, bus->busnr,
+                       bus->parent ? bus->parent->info->name : "<none>");
+    }
+}
diff --git a/hw/qdev.h b/hw/qdev.h
index 18321b3..c4b04c1 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -32,14 +32,17 @@ struct BusInfo {
     const char *name;
     size_t size;
     bus_dev_print print;
+    int next_busnr;
 };
 
 struct BusState {
     DeviceState *parent;
     BusInfo *info;
+    int busnr;
     const char *name;
     LIST_HEAD(, DeviceState) children;
     LIST_ENTRY(BusState) sibling;
+    TAILQ_ENTRY(BusState) next;
 };
 
 /*** Board API.  This should go away once we have a machine config file.  ***/
@@ -117,11 +120,13 @@ void *qdev_get_prop_ptr(DeviceState *dev, const char *name);
 /*** BUS API. ***/
 
 BusState *qbus_create(BusInfo *info, DeviceState *parent, const char *name);
+BusState *qbus_find(const char *type, const char *name, int busnr);
 
 #define FROM_QBUS(type, dev) DO_UPCAST(type, qbus, dev)
 
 /*** monitor commands ***/
 
 void do_info_qtree(Monitor *mon);
+void do_info_qbus(Monitor *mon);
 
 #endif
diff --git a/monitor.c b/monitor.c
index bad79fe..39ce99f 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1759,6 +1759,8 @@ static const mon_cmd_t info_cmds[] = {
       "", "show balloon information" },
     { "qtree", "", do_info_qtree,
       "", "show device tree" },
+    { "qbus", "", do_info_qbus,
+      "", "show qdev bus list" },
     { NULL, NULL, },
 };
 
-- 
1.6.2.5