From 855ed04a3758b205e84b269f92d26ab36ed8e2f7 Mon Sep 17 00:00:00 2001 From: Ruslan Bilovol Date: Mon, 23 Nov 2015 09:56:38 +0100 Subject: [PATCH] usb: gadget: udc-core: independent registration of gadgets and gadget drivers Change behavior during registration of gadgets and gadget drivers in udc-core. Instead of previous approach when for successful probe of usb gadget driver at least one usb gadget should be already registered use another one where gadget drivers and gadgets can be registered in udc-core independently. Independent registration of gadgets and gadget drivers is useful for built-in into kernel gadget and gadget driver case - because it's possible that gadget is really probed only on late_init stage (due to deferred probe) whereas gadget driver's probe is silently failed on module_init stage due to no any UDC added. Also it is useful for modules case - now there is no difference what module to insert first: gadget module or gadget driver one. Tested-by: Maxime Ripard Signed-off-by: Ruslan Bilovol [simplified code as requested by Alan Stern and Felipe Balbi, fixed checkpatch issues] Signed-off-by: Marek Szyprowski Tested-by: Peter Chen Signed-off-by: Felipe Balbi --- drivers/usb/gadget/udc/udc-core.c | 41 ++++++++++++++++++++++++------- include/linux/usb/gadget.h | 2 ++ 2 files changed, 34 insertions(+), 9 deletions(-) diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c index f76ebc8c1ed2..fd73a3ea07c2 100644 --- a/drivers/usb/gadget/udc/udc-core.c +++ b/drivers/usb/gadget/udc/udc-core.c @@ -51,8 +51,12 @@ struct usb_udc { static struct class *udc_class; static LIST_HEAD(udc_list); +static LIST_HEAD(gadget_driver_pending_list); static DEFINE_MUTEX(udc_lock); +static int udc_bind_to_driver(struct usb_udc *udc, + struct usb_gadget_driver *driver); + /* ------------------------------------------------------------------------- */ #ifdef CONFIG_HAS_DMA @@ -356,6 +360,7 @@ 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); @@ -403,6 +408,18 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget, usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED); 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) + goto err4; + list_del(&driver->pending); + break; + } + } + mutex_unlock(&udc_lock); return 0; @@ -473,10 +490,14 @@ void usb_del_gadget_udc(struct usb_gadget *gadget) mutex_lock(&udc_lock); list_del(&udc->list); - mutex_unlock(&udc_lock); - if (udc->driver) + if (udc->driver) { + struct usb_gadget_driver *driver = udc->driver; + usb_gadget_remove_driver(udc); + list_add(&driver->pending, &gadget_driver_pending_list); + } + mutex_unlock(&udc_lock); kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE); flush_work(&gadget->work); @@ -535,11 +556,7 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver) if (!ret) break; } - if (ret) - ret = -ENODEV; - else if (udc->driver) - ret = -EBUSY; - else + if (!ret && !udc->driver) goto found; } else { list_for_each_entry(udc, &udc_list, list) { @@ -549,9 +566,11 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver) } } - pr_debug("couldn't find an available UDC\n"); + 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); mutex_unlock(&udc_lock); - return ret; + return 0; found: ret = udc_bind_to_driver(udc, driver); mutex_unlock(&udc_lock); @@ -577,6 +596,10 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver) break; } + if (ret) { + list_del(&driver->pending); + ret = 0; + } mutex_unlock(&udc_lock); return ret; } diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index ce2188d338e6..92467eea76de 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -1014,6 +1014,7 @@ static inline int usb_gadget_activate(struct usb_gadget *gadget) * @driver: Driver model state for this driver. * @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. * * Devices are disabled till a gadget driver successfully bind()s, which * means the driver will handle setup() requests needed to enumerate (and @@ -1076,6 +1077,7 @@ struct usb_gadget_driver { struct device_driver driver; char *udc_name; + struct list_head pending; };