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usb: gadget: udc-core: Rescan pending list on driver unbind

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Since:

commit 855ed04a37 ("usb: gadget: udc-core: independent registration
of gadgets and gadget drivers")

if we load gadget module but there is no free udc available
then it will be stored on a pending gadgets list.

$ modprobe g_zero.ko
$ modprobe g_ether.ko
[] udc-core: couldn't find an available UDC - added [g_ether] to list
of pending drivers

We scan this list each time when new UDC appears in system.
But we can get a free UDC each time after gadget unbind.
This commit add scanning of that list directly after unbinding
gadget from udc.

Thanks to this, when we unload first gadget:

$ rmmod g_zero.ko

gadget which is pending is automatically
attached to that UDC (if name matches).

Fixes: 855ed04a37  ("usb: gadget: udc-core: independent registration of gadgets and gadget drivers")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Krzysztof Opasiak 2017-01-16 08:40:57 +01:00 committed by Felipe Balbi
parent 49def18533
commit 8236800da1
1 changed files with 31 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
drivers/usb/gadget/udc/core.c
View File

@ -1080,6 +1080,24 @@ static void usb_udc_nop_release(struct device *dev)
dev_vdbg(dev, "%s\n", __func__);
}
/* should be called with udc_lock held */
static int check_pending_gadget_drivers(struct usb_udc *udc)
{
struct usb_gadget_driver *driver;
int ret = 0;
list_for_each_entry(driver, &gadget_driver_pending_list, pending)
if (!driver->udc_name || strcmp(driver->udc_name,
dev_name(&udc->dev)) == 0) {
ret = udc_bind_to_driver(udc, driver);
if (ret != -EPROBE_DEFER)
list_del(&driver->pending);
break;
}
return ret;
}
/**
* usb_add_gadget_udc_release - adds a new gadget to the udc class driver list
* @parent: the parent device to this udc. Usually the controller driver's
@ -1093,7 +1111,6 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
void (*release)(struct device *dev))
{
struct usb_udc *udc;
struct usb_gadget_driver *driver;
int ret = -ENOMEM;
udc = kzalloc(sizeof(*udc), GFP_KERNEL);
@ -1136,17 +1153,9 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
udc->vbus = true;
/* pick up one of pending gadget drivers */
list_for_each_entry(driver, &gadget_driver_pending_list, pending) {
if (!driver->udc_name || strcmp(driver->udc_name,
dev_name(&udc->dev)) == 0) {
ret = udc_bind_to_driver(udc, driver);
if (ret != -EPROBE_DEFER)
list_del(&driver->pending);
if (ret)
goto err5;
break;
}
}
ret = check_pending_gadget_drivers(udc);
if (ret)
goto err5;
mutex_unlock(&udc_lock);
@ -1356,14 +1365,22 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
return -EINVAL;
mutex_lock(&udc_lock);
list_for_each_entry(udc, &udc_list, list)
list_for_each_entry(udc, &udc_list, list) {
if (udc->driver == driver) {
usb_gadget_remove_driver(udc);
usb_gadget_set_state(udc->gadget,
USB_STATE_NOTATTACHED);
USB_STATE_NOTATTACHED);
/* Maybe there is someone waiting for this UDC? */
check_pending_gadget_drivers(udc);
/*
* For now we ignore bind errors as probably it's
* not a valid reason to fail other's gadget unbind
*/
ret = 0;
break;
}
}
if (ret) {
list_del(&driver->pending);