From d6a267c618f13092b586c4a155bf90ef6a2fc301 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 18 Feb 2016 11:34:43 +0100 Subject: [PATCH] usb: gadget: provide interface for legacy gadgets to get UDC name Since commit 2a0f75372612193b831d2193ae72ab7fb7548621 ("usb: gadget: udc-core: independent registration of gadgets and gadget drivers") gadget drivers can not assume that UDC drivers are already available on their initialization. This broke the HACK, which was used in gadgetfs driver, to get UDC controller name. This patch removes this hack and replaces it by additional function in the UDC core (which is usefully only for legacy drivers, please don't use it in the new code). Reported-by: Vegard Nossum Signed-off-by: Marek Szyprowski Tested-by: Vegard Nossum Signed-off-by: Felipe Balbi --- drivers/usb/gadget/legacy/inode.c | 28 +++------------------------- drivers/usb/gadget/udc/udc-core.c | 30 ++++++++++++++++++++++++++++++ include/linux/usb/gadget.h | 1 + 3 files changed, 34 insertions(+), 25 deletions(-) diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index 87fb0fd6aaabe..5cdaf0150a4ed 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -1699,28 +1699,6 @@ static struct usb_gadget_driver gadgetfs_driver = { }; /*----------------------------------------------------------------------*/ - -static void gadgetfs_nop(struct usb_gadget *arg) { } - -static int gadgetfs_probe(struct usb_gadget *gadget, - struct usb_gadget_driver *driver) -{ - CHIP = gadget->name; - return -EISNAM; -} - -static struct usb_gadget_driver probe_driver = { - .max_speed = USB_SPEED_HIGH, - .bind = gadgetfs_probe, - .unbind = gadgetfs_nop, - .setup = (void *)gadgetfs_nop, - .disconnect = gadgetfs_nop, - .driver = { - .name = "nop", - }, -}; - - /* DEVICE INITIALIZATION * * fd = open ("/dev/gadget/$CHIP", O_RDWR) @@ -1971,9 +1949,7 @@ gadgetfs_fill_super (struct super_block *sb, void *opts, int silent) if (the_device) return -ESRCH; - /* fake probe to determine $CHIP */ - CHIP = NULL; - usb_gadget_probe_driver(&probe_driver); + CHIP = usb_get_gadget_udc_name(); if (!CHIP) return -ENODEV; @@ -2034,6 +2010,8 @@ gadgetfs_kill_sb (struct super_block *sb) put_dev (the_device); the_device = NULL; } + kfree(CHIP); + CHIP = NULL; } /*----------------------------------------------------------------------*/ diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c index b86a6f03592ec..4151597e9d288 100644 --- a/drivers/usb/gadget/udc/udc-core.c +++ b/drivers/usb/gadget/udc/udc-core.c @@ -442,6 +442,36 @@ err1: } EXPORT_SYMBOL_GPL(usb_add_gadget_udc_release); +/** + * usb_get_gadget_udc_name - get the name of the first UDC controller + * This functions returns the name of the first UDC controller in the system. + * Please note that this interface is usefull only for legacy drivers which + * assume that there is only one UDC controller in the system and they need to + * get its name before initialization. There is no guarantee that the UDC + * of the returned name will be still available, when gadget driver registers + * itself. + * + * Returns pointer to string with UDC controller name on success, NULL + * otherwise. Caller should kfree() returned string. + */ +char *usb_get_gadget_udc_name(void) +{ + struct usb_udc *udc; + char *name = NULL; + + /* For now we take the first available UDC */ + mutex_lock(&udc_lock); + list_for_each_entry(udc, &udc_list, list) { + if (!udc->driver) { + name = kstrdup(udc->gadget->name, GFP_KERNEL); + break; + } + } + mutex_unlock(&udc_lock); + return name; +} +EXPORT_SYMBOL_GPL(usb_get_gadget_udc_name); + /** * usb_add_gadget_udc - adds a new gadget to the udc class driver list * @parent: the parent device to this udc. Usually the controller diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index 42527297f2183..dd7c53279e6ac 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -1136,6 +1136,7 @@ extern int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget, void (*release)(struct device *dev)); extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget); extern void usb_del_gadget_udc(struct usb_gadget *gadget); +extern char *usb_get_gadget_udc_name(void); /*-------------------------------------------------------------------------*/ -- 2.39.5