[U-Boot] [PATCH] usb: ci_udc: fix interaction with CONFIG_USB_ETH_CDC

["Jörg Krause" <jkrause@posteo.de>]

I added the last series of patches beginning from 2014-06-10 for testing 
purposes. The patches from 2014-05-29 were already applied.

First series of patches:

    Applying: usb: ci_udc: call udc_disconnect() from ci_pullup()
    Applying: usb: ci_udc: fix freeing of ep0 req
    Applying: usb: ci_udc: fix probe error cleanup
    Applying: usb: ci_udc: clean up all allocations in unregister

Calling tftp the first time after a reset runs fine, but calling it a 
second time ends always in a crash. I have to reset the device.

Next patch:

    Applying: usb: ci_udc: terminate ep0 INs with a zlp when required

Did not help.

Next patch:

    Applying: usb: ci_udc: fix interaction with CONFIG_USB_ETH_CDC

This helps! U-Boot does not crash anymore. But there is still a problem: 
I have to wait some seconds before I can run a second time tftp. This is 
the output from U-Boot:

    => run update_rootfs
    Updating rootfs ...
    using ci_udc, OUT ep- IN ep- STATUS ep-
    high speed config #1: 2 mA, Ethernet Gadget, using CDC Ethernet
    USB network up!
    Using usb_ether device
    [snip]

    => run update_rootfs
    Updating rootfs ...
    using ci_udc, OUT ep- IN ep- STATUS ep-
    high speed config #1: 2 mA, Ethernet Gadget, using CDC Ethernet
    ERROR: The remote end did not respond in time.
    at drivers/usb/gadget/ether.c:2388/usb_eth_init()

Wait some seconds ...

    => run update_rootfs
    Updating rootfs ...
    using ci_udc, OUT ep- IN ep- STATUS ep-
    high speed config #1: 2 mA, Ethernet Gadget, using CDC Ethernet
    USB network up!
    Using usb_ether device
    [snip]

Best regards
J?rg Krause

On 06/25/2014 06:06 PM, Stephen Warren wrote:
> On 06/25/2014 07:51 AM, Marek Vasut wrote:
>> On Monday, June 23, 2014 at 08:02:48 PM, Stephen Warren wrote:
>>
>> +CC Jorg, rest of email is intact. Jorg, does this patch fix your issue?
> Jorg's issue was timeouts during transfers, whereas this patch addresses
> cleanup issues once the device isn't being used any more. I can't
> imagine how this patch could influence the issue Jorg is seeing.
>
>>> From: Stephen Warren <swarren@nvidia.com>
>>>
>>> ci_udc.c's usb_gadget_unregister_driver() doesn't call driver->unbind()
>>> unlike other USB gadget drivers. Fix it to do this.
>>>
>>> Without this, when ether.c's CDC Ethernet device is torn down,
>>> eth_unbind() is never called, so dev->gadget is never set to NULL.
>>> For some reason, usb_eth_halt() is called both at the end of the first
>>> use of the Ethernet device, and prior to any subsequent use. Since
>>> dev->gadget is never cleared, all calls to usb_eth_halt() attempt to
>>> stop, disconnect, and clean up the device, resulting in double cleanup,
>>> which hangs U-Boot on my Tegra device at least.
>>>
>>> ci_udc allocates its own singleton EP0 request object, and cleans it up
>>> during usb_gadget_unregister_driver(). This appears necessary when using
>>> the USB gadget framework in U-Boot, since that does not allocate/free
>>> the EP0 request. However, the CDC Ethernet driver *does* allocate and
>>> free its own EP0 requests. Consequently, we must protect
>>> ci_ep_free_request() against double-freeing the request.