Re: usb: gadget breakage on N900: bind UDC by name passed via usb_gadget_driver structure

Ruslan Bilovol
2016-03-25T03:21:59Z

OK, so at last I finished charging of my N900; found 1.8V USB
to UART adapter and soldered it to the phone.

I managed to boot N900 with working USB gadget (builtin g_ether)
in boardfile mode, can ping it from PC and transfer data. I don't
see any issue (except of musb name issue in twl phy driver, I've
already sent a fix for that: https://lkml.org/lkml/2016/3/24/670 )

Pavel, I still don't see how you've got your issue, please share
more detials

Regards,
Ruslan

On Thu, Mar 24, 2016 at 2:45 AM, Ruslan Bilovol
<ruslan.bilovol@gmail.com> wrote:
> Hi Pavel,
>
> I didn't use my N900 for years, it is deeply discharged and can't
> boot, so I left it connected overnight to the wall adapter to let it
> get some juice.
>
> Meanwhile I looked into sources and still can't understand how
> it happens.
> Could you please attach your full .config and also dmesg
> without hacks?
>
> Regards,
> Ruslan
>
> On Wed, Mar 23, 2016 at 2:21 PM, Pavel Machek <pavel@ucw.cz> wrote:
>> 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