usb: gadget: Fix binding to UDC via configfs interface
By default user could store only valid UDC name in configfs UDC
attr by doing:
echo $UDC_NAME > UDC
Commit (855ed04 "usb: gadget: udc-core: independent registration of
gadgets and gadget drivers") broke this behavior and allowed to store
any arbitrary string in UDC file and udc core was waiting for such
controller to appear.
echo "any arbitrary string here" > UDC
This commit fix this by adding a flag which prevents configfs
gadget from being added to list of pending drivers if UDC with
given name has not been found.
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index b6f60ca..70cf347 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -1401,6 +1401,7 @@
.owner = THIS_MODULE,
.name = "configfs-gadget",
},
+ .match_existing_only = 1,
};
static struct config_group *gadgets_make(
diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
index 6e8300d..e1b2dce 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -603,11 +603,15 @@
}
}
- list_add_tail(&driver->pending, &gadget_driver_pending_list);
- pr_info("udc-core: couldn't find an available UDC - added [%s] to list of pending drivers\n",
- driver->function);
+ if (!driver->match_existing_only) {
+ list_add_tail(&driver->pending, &gadget_driver_pending_list);
+ pr_info("udc-core: couldn't find an available UDC - added [%s] to list of pending drivers\n",
+ driver->function);
+ ret = 0;
+ }
+
mutex_unlock(&udc_lock);
- return 0;
+ return ret;
found:
ret = udc_bind_to_driver(udc, driver);
mutex_unlock(&udc_lock);
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 457651b..fefe8b0 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -1034,6 +1034,8 @@
* @udc_name: A name of UDC this driver should be bound to. If udc_name is NULL,
* this driver will be bound to any available UDC.
* @pending: UDC core private data used for deferred probe of this driver.
+ * @match_existing_only: If udc is not found, return an error and don't add this
+ * gadget driver to list of pending driver
*
* Devices are disabled till a gadget driver successfully bind()s, which
* means the driver will handle setup() requests needed to enumerate (and
@@ -1097,6 +1099,7 @@
char *udc_name;
struct list_head pending;
+ unsigned match_existing_only:1;
};
