Module autoprobing support for virtio drivers.

This adds the logic to convert the virtio ids into module aliases, and
includes a modalias entry in sysfs and the env var to make probing work.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/virtio/virtio.c

@@ -20,10 +20,19 @@ static ssize_t status_show(struct device *_d,
 	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
 	return sprintf(buf, "0x%08x", dev->config->get_status(dev));
 }
+static ssize_t modalias_show(struct device *_d,
+			     struct device_attribute *attr, char *buf)
+{
+	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
+
+	return sprintf(buf, "virtio:d%08Xv%08X\n",
+		       dev->id.device, dev->id.vendor);
+}
 static struct device_attribute virtio_dev_attrs[] = {
 	__ATTR_RO(device),
 	__ATTR_RO(vendor),
 	__ATTR_RO(status),
+	__ATTR_RO(modalias),
 	__ATTR_NULL
 };
 
@@ -51,10 +60,19 @@ static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
 	return 0;
 }
 
+static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
+{
+	struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
+
+	return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
+			      dev->id.device, dev->id.vendor);
+}
+
 static struct bus_type virtio_bus = {
 	.name  = "virtio",
 	.match = virtio_dev_match,
 	.dev_attrs = virtio_dev_attrs,
+	.uevent = virtio_uevent,
 };
 
 static void add_status(struct virtio_device *dev, unsigned status)

scripts/mod/file2alias.c

@@ -525,6 +525,20 @@ static int do_ssb_entry(const char *filename,
 	return 1;
 }
 
+/* Looks like: virtio:dNvN */
+static int do_virtio_entry(const char *filename, struct virtio_device_id *id,
+			   char *alias)
+{
+	id->device = TO_NATIVE(id->device);
+	id->vendor = TO_NATIVE(id->vendor);
+
+	strcpy(alias, "virtio:");
+	ADD(alias, "d", 1, id->device);
+	ADD(alias, "v", id->vendor != VIRTIO_DEV_ANY_ID, id->vendor);
+
+	return 1;
+}
+
 /* Ignore any prefix, eg. v850 prepends _ */
 static inline int sym_is(const char *symbol, const char *name)
 {
@@ -651,6 +665,10 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 		do_table(symval, sym->st_size,
 			 sizeof(struct ssb_device_id), "ssb",
 			 do_ssb_entry, mod);
+	else if (sym_is(symname, "__mod_virtio_device_table"))
+		do_table(symval, sym->st_size,
+			 sizeof(struct virtio_device_id), "virtio",
+			 do_virtio_entry, mod);
 	free(zeros);
 }