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Date: Thu, 8 Feb 2024 20:46:05 -0600
From: Bjorn Andersson <andersson@kernel.org>
To: Krishna Kurapati <quic_kriskura@quicinc.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
	Rob Herring <robh+dt@kernel.org>, Wesley Cheng <quic_wcheng@quicinc.com>, 
	Konrad Dybcio <konrad.dybcio@linaro.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
	Conor Dooley <conor+dt@kernel.org>, Thinh Nguyen <Thinh.Nguyen@synopsys.com>, 
	Felipe Balbi <balbi@kernel.org>, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, 
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, quic_ppratap@quicinc.com, 
	quic_jackp@quicinc.com, Johan Hovold <johan@kernel.org>, 
	Johan Hovold <johan+linaro@kernel.org>
Subject: Re: [PATCH v14 3/9] usb: dwc3: core: Skip setting event buffers for
 host only controllers
Message-ID: <nty2l5b6fsu3owmnwrfcrp7w67zmfi3guvxqy2cwjtchnerjkp@n42o34comila>
References: <20240206051825.1038685-1-quic_kriskura@quicinc.com>
 <20240206051825.1038685-4-quic_kriskura@quicinc.com>
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In-Reply-To: <20240206051825.1038685-4-quic_kriskura@quicinc.com>

On Tue, Feb 06, 2024 at 10:48:19AM +0530, Krishna Kurapati wrote:
> On some SoC's like SA8295P where the tertiary controller is host-only
> capable, GEVTADDRHI/LO, GEVTSIZ, GEVTCOUNT registers are not accessible.
> Trying to access them leads to a crash.
> 
> For DRD/Peripheral supported controllers, event buffer setup is done
> again in gadget_pullup. Skip setup or cleanup of event buffers if
> controller is host-only capable.
> 
> Suggested-by: Johan Hovold <johan@kernel.org>
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> Reviewed-by: Johan Hovold <johan+linaro@kernel.org>

Reviewed-by: Bjorn Andersson <andersson@kernel.org>

Regards,
Bjorn

> ---
>  drivers/usb/dwc3/core.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 965eaad195fb..c47fec10b231 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -486,6 +486,13 @@ static void dwc3_free_event_buffers(struct dwc3 *dwc)
>  static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned int length)
>  {
>  	struct dwc3_event_buffer *evt;
> +	unsigned int hw_mode;
> +
> +	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
> +	if (hw_mode == DWC3_GHWPARAMS0_MODE_HOST) {
> +		dwc->ev_buf = NULL;
> +		return 0;
> +	}
>  
>  	evt = dwc3_alloc_one_event_buffer(dwc, length);
>  	if (IS_ERR(evt)) {
> @@ -507,6 +514,9 @@ int dwc3_event_buffers_setup(struct dwc3 *dwc)
>  {
>  	struct dwc3_event_buffer	*evt;
>  
> +	if (!dwc->ev_buf)
> +		return 0;
> +
>  	evt = dwc->ev_buf;
>  	evt->lpos = 0;
>  	dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(0),
> @@ -524,6 +534,9 @@ void dwc3_event_buffers_cleanup(struct dwc3 *dwc)
>  {
>  	struct dwc3_event_buffer	*evt;
>  
> +	if (!dwc->ev_buf)
> +		return;
> +
>  	evt = dwc->ev_buf;
>  
>  	evt->lpos = 0;
> -- 
> 2.34.1
>