[4.4,068/134] usb: dwc2: Make sure we disconnect the gadget state

[Ben Hutchings <ben.hutchings@codethink.co.uk>]

On Mon, 2018-03-19 at 19:05 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: John Stultz <john.stultz@linaro.org>
> 
> 
> [ Upstream commit dad3f793f20fbb5c0c342f0f5a0bdf69a4d76089 ]

Maybe we should also have:

commit d2471d4a24dfbff5e463d382e2c6fec7d7e25a09
Author: John Stultz <john.stultz@linaro.org>
Date:   Mon Oct 23 14:32:48 2017 -0700

    usb: dwc2: Improve gadget state disconnection handling

Ben.

> I had seen some odd behavior with HiKey's usb-gadget interface
> that I finally seemed to have chased down. Basically every other
> time I plugged in the OTG port, the gadget interface would
> properly initialize. The other times, I'd get a big WARN_ON
> in dwc2_hsotg_init_fifo() about the fifo_map not being clear.
> 
> Ends up if we don't disconnect the gadget state, the fifo-map
> doesn't get cleared properly, which causes WARN_ON messages and
> also results in the device not properly being setup as a gadget
> every other time the OTG port is connected.
> 
> So this patch adds a call to dwc2_hsotg_disconnect() in the
> reset path so the state is properly cleared.
> 
> With it, the gadget interface initializes properly on every
> plug in.
> 
> Cc: Wei Xu <xuwei5@hisilicon.com>
> Cc: Guodong Xu <guodong.xu@linaro.org>
> Cc: Amit Pundir <amit.pundir@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: John Youn <johnyoun@synopsys.com>
> Cc: Douglas Anderson <dianders@chromium.org>
> Cc: Chen Yu <chenyu56@huawei.com>
> Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-usb@vger.kernel.org
> Acked-by: John Youn <johnyoun@synopsys.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/usb/dwc2/hcd.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -1385,6 +1385,7 @@ static void dwc2_conn_id_status_change(s
>  		dwc2_core_init(hsotg, false, -1);
>  		dwc2_enable_global_interrupts(hsotg);
>  		spin_lock_irqsave(&hsotg->lock, flags);
> +		dwc2_hsotg_disconnect(hsotg);
>  		dwc2_hsotg_core_init_disconnected(hsotg, false);
>  		spin_unlock_irqrestore(&hsotg->lock, flags);
> 		dwc2_hsotg_core_connect(hsotg);