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From:   Felipe Balbi <balbi@kernel.org>
To:     Dejin Zheng <zhengdejin5@gmail.com>, gregkh@linuxfoundation.org,
        linux-usb@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, Dejin Zheng <zhengdejin5@gmail.com>
Subject: Re: [PATCH v1] usb: dwc3: core: fix a issue about clear connect state
In-Reply-To: <20201018134734.10406-1-zhengdejin5@gmail.com>
References: <20201018134734.10406-1-zhengdejin5@gmail.com>
Date:   Tue, 27 Oct 2020 11:12:14 +0200
Message-ID: <87pn54c9sh.fsf@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Hi,

Dejin Zheng <zhengdejin5@gmail.com> writes:
> According to Synopsys Programming Guide chapter 2.2 Register Resets,
> it cannot reset the DCTL register by set DCTL.CSFTRST for Core Soft Reset,
> if DWC3 controller as a slave device and stay connected with a usb host,
> then, reboot linux, it will fail to reinitialize dwc3 as a slave device
> when the DWC3 controller did not power off. because the connection status
> is incorrect, so we also need clear DCTL.RUN_STOP bit for disable connect
> when do core soft reset.
>
> Fixes: f59dcab176293b6 ("usb: dwc3: core: improve reset sequence")
> Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
> ---
>  drivers/usb/dwc3/core.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 2eb34c8b4065..239636c454c2 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -256,6 +256,7 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
>  
>  	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
>  	reg |= DWC3_DCTL_CSFTRST;
> +	reg &= ~DWC3_DCTL_RUN_STOP;

as I mentioned in the other thread, I would rather figure out why we're
getting to probe() with RUN_STOP already set.

-- 
balbi