On Mon 2016-03-21 12:51:51, Marek Szyprowski wrote:
> Hi
> 
> On 2016-03-18 21:20, Pavel Machek wrote:
> >Hi!
> >
> >>>USB gadget stops working for me on n900, if I merge
> >>Could you please give us more details?
> >>Which gadget driver do you use (g_nokia?)
> >Ok, so I could get it to work with v4.5, and this patch. I'm including
> >my config, too. No, I don't think I'm using g_nokia.
> 
> This shows that there are some serious problems, probably with your udc
> driver, which doesn't handle deferred probe properly. Your patch workaround
> it by waiting some predefined time before registering gadget driver, however
> this is not the proper way. Please try to isolate what exactly is needed to
> get the gadget driver registered properly in your system or at least please
> provide some logs from the failed case.

Well, Ruslan said he has n900 available, so I provided requested
information.

This is the dmesg with the hack:

[    0.623138] of_get_named_gpiod_flags: parsed 'ti,power-gpio'
property of node '/ocp/spi@480ba00
0/wl1251@0[0]' - status (0)
[    0.623565] wl1251: ERROR vio regulator missing: -517
[    0.624359] musb probe HACK cf9a9e00
[    0.624420] musb probe HACK/2 cf9a9e00
[    0.624511] musb probe HACK/3 cf9a9e00
[    0.624755] HS USB OTG: no transceiver configured
[    0.624847] musb-hdrc musb-hdrc.0.auto: musb_init_controller failed
with status -517
[    0.626525] mousedev: PS/2 mouse device common for all mice
...
[    2.877441] ieee80211 phy1: Selected rate control algorithm
'minstrel'
[    2.879882] wl1251: loaded
[    2.889617] wl1251: initialized
[    2.897521] Two musb controllers?  HACK
[    2.904968] musb probe HACK cf9a9e00
[    2.912048] musb probe HACK/2 cf9a9e00
[    2.918823] musb probe HACK/3 cf9a9e00
[    2.928985] musb-hdrc: ConfigData=0xde (UTMI-8, dyn FIFOs, bulk
combine, bulk split, HB-ISO Rx, HB-ISO Tx, SoftConn)
[    2.929016] musb-hdrc: MHDRC RTL version 1.400
[    2.929046] musb-hdrc: setup fifo_mode 4
[    2.929077] musb-hdrc: 28/31 max ep, 16384/16384 memory
[    2.930511] tsc2005 spi1.0: GPIO lookup for consumer reset
[    2.930541] tsc2005 spi1.0: using device tree for GPIO lookup

In the kernel without the hack, there'll be only the first part of the
dmesg, AFAICT.

If there's an interest, I can repeat the test without the hack.

Thanks,
                                                                        Pavel


> >diff --git a/drivers/usb/gadget/udc/udc-core.c 
> >b/drivers/usb/gadget/udc/udc-core.c
> >index b86a6f0..bee109f 100644
> >--- a/drivers/usb/gadget/udc/udc-core.c
> >+++ b/drivers/usb/gadget/udc/udc-core.c
> >@@ -542,14 +542,37 @@ err1:
> >     return ret;
> >  }
> >-int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> >+int usb_udc_attach_driver(const char *name, struct usb_gadget_driver 
> >*driver)
> >+{
> >+    struct usb_udc *udc = NULL;
> >+    int ret = -ENODEV;
> >+
> >+    mutex_lock(&udc_lock);
> >+    list_for_each_entry(udc, &udc_list, list) {
> >+            ret = strcmp(name, dev_name(&udc->dev));
> >+            if (!ret)
> >+                    break;
> >+    }
> >+    if (ret) {
> >+            ret = -ENODEV;
> >+            goto out;
> >+    }
> >+    if (udc->driver) {
> >+            ret = -EBUSY;
> >+            goto out;
> >+    }
> >+    ret = udc_bind_to_driver(udc, driver);
> >+out:
> >+    mutex_unlock(&udc_lock);
> >+    return ret;
> >+}
> >+EXPORT_SYMBOL_GPL(usb_udc_attach_driver);
> >+
> >+int __usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> >  {
> >     struct usb_udc          *udc = NULL;
> >     int                     ret = -ENODEV;
> >-    if (!driver || !driver->bind || !driver->setup)
> >-            return -EINVAL;
> >-
> >     mutex_lock(&udc_lock);
> >     if (driver->udc_name) {
> >             list_for_each_entry(udc, &udc_list, list) {
> >@@ -567,16 +590,47 @@ int usb_gadget_probe_driver(struct usb_gadget_driver 
> >*driver)
> >             }
> >     }
> >-    list_add_tail(&driver->pending, &gadget_driver_pending_list);
> >+//  list_add_tail(&driver->pending, &gadget_driver_pending_list); FIXME
> >     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 0;
> >+    return ret;
> >  found:
> >     ret = udc_bind_to_driver(udc, driver);
> >     mutex_unlock(&udc_lock);
> >     return ret;
> >  }
> >+
> >+#define USB_GADGET_BIND_RETRIES             5
> >+#define USB_GADGET_BIND_TIMEOUT             (3 * HZ)
> >+static void usb_gadget_work(struct work_struct *work)
> >+{
> >+    struct usb_gadget_driver *driver = container_of(work,
> >+                                            struct usb_gadget_driver,
> >+                                            work.work);
> >+    int res;
> >+    
> >+    if (driver->retries++ > USB_GADGET_BIND_RETRIES) {
> >+            pr_err("couldn't find an available UDC\n");
> >+            return;
> >+    }
> >+
> >+    res = __usb_gadget_probe_driver(driver);
> >+    if (res == -ENODEV)
> >+            schedule_delayed_work(&driver->work, USB_GADGET_BIND_TIMEOUT);
> >+}
> >+
> >+int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> >+{
> >+    if (!driver || !driver->bind || !driver->setup)
> >+            return -EINVAL;
> >+
> >+    INIT_DELAYED_WORK(&driver->work, usb_gadget_work);
> >+    schedule_delayed_work(&driver->work, 0);
> >+
> >+    return 0;
> >+}
> >  EXPORT_SYMBOL_GPL(usb_gadget_probe_driver);
> >  int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
> >@@ -587,6 +641,8 @@ int usb_gadget_unregister_driver(struct 
> >usb_gadget_driver *driver)
> >     if (!driver || !driver->unbind)
> >             return -EINVAL;
> >+    cancel_delayed_work(&driver->work);
> >+
> >     mutex_lock(&udc_lock);
> >     list_for_each_entry(udc, &udc_list, list)
> >             if (udc->driver == driver) {
> >@@ -747,7 +803,7 @@ static int __init usb_udc_init(void)
> >     udc_class->dev_uevent = usb_udc_uevent;
> >     return 0;
> >  }
> >-subsys_initcall(usb_udc_init);
> >+late_initcall_sync(usb_udc_init);
> >  static void __exit usb_udc_exit(void)
> >  {
> >diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> >index d82d006..adb1e68 100644
> >--- a/include/linux/usb/gadget.h
> >+++ b/include/linux/usb/gadget.h
> >@@ -1014,6 +1014,8 @@ static inline int usb_gadget_activate(struct 
> >usb_gadget *gadget)
> >   * @resume: Invoked on USB resume.  May be called in_interrupt.
> >   * @reset: Invoked on USB bus reset. It is mandatory for all gadget drivers
> >   * and should be called in_interrupt.
> >+ * @work: Gadget work used to bind to the USB controller.
> >+ * @retries: Gadget retries to bind to the USB controller.
> >   * @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.
> >@@ -1075,6 +1077,8 @@ struct usb_gadget_driver {
> >     void                    (*suspend)(struct usb_gadget *);
> >     void                    (*resume)(struct usb_gadget *);
> >     void                    (*reset)(struct usb_gadget *);
> >+    struct delayed_work     work;
> >+    int                     retries;
> >     /* FIXME support safe rmmod */
> >     struct device_driver    driver;
> >
> 
> Best regards

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) 
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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