Re: [RFC v4 3/5] usb: dwc3: core: Do not setup event buffers for host only controllers

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Sun, Jan 15, 2023, Krishna Kurapati wrote:
> Multiport controllers being host-only capable do not have GEVNTADDR
> HI/LO, SIZE, COUNT reigsters present. Accsesing them to setup event

I think you should reword "present" to something else. They're still
present, but those registers are to be set while operating in device
mode. The rest looks fine.

Thanks,
Thinh

> buffers during core_init can cause an SMMU Fault. Avoid event buffers
> setup if the GHWPARAMS0 tells that the controller is host-only.
> 
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
>  drivers/usb/dwc3/core.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 7e0a9a598dfd..f61ebddaecc0 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -871,9 +871,12 @@ static void dwc3_clk_disable(struct dwc3 *dwc)
>  
>  static void dwc3_core_exit(struct dwc3 *dwc)
>  {
> -	int i;
> +	int		i;
> +	unsigned int	hw_mode;
>  
> -	dwc3_event_buffers_cleanup(dwc);
> +	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
> +	if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST)
> +		dwc3_event_buffers_cleanup(dwc);
>  
>  	usb_phy_set_suspend(dwc->usb2_phy, 1);
>  	usb_phy_set_suspend(dwc->usb3_phy, 1);
> @@ -1246,10 +1249,12 @@ static int dwc3_core_init(struct dwc3 *dwc)
>  		}
>  	}
>  
> -	ret = dwc3_event_buffers_setup(dwc);
> -	if (ret) {
> -		dev_err(dwc->dev, "failed to setup event buffers\n");
> -		goto err4;
> +	if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST) {
> +		ret = dwc3_event_buffers_setup(dwc);
> +		if (ret) {
> +			dev_err(dwc->dev, "failed to setup event buffers\n");
> +			goto err4;
> +		}
>  	}
>  
>  	/*
> @@ -1886,7 +1891,7 @@ static int dwc3_probe(struct platform_device *pdev)
>  	struct resource		*res, dwc_res;
>  	struct dwc3		*dwc;
>  	int			ret, i;
> -
> +	unsigned int		hw_mode;
>  	void __iomem		*regs;
>  
>  	dwc = devm_kzalloc(dev, sizeof(*dwc), GFP_KERNEL);
> @@ -2063,7 +2068,9 @@ static int dwc3_probe(struct platform_device *pdev)
>  err5:
>  	dwc3_debugfs_exit(dwc);
>  
> -	dwc3_event_buffers_cleanup(dwc);
> +	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
> +	if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST)
> +		dwc3_event_buffers_cleanup(dwc);
>  
>  	usb_phy_set_suspend(dwc->usb2_phy, 1);
>  	usb_phy_set_suspend(dwc->usb3_phy, 1);
> -- 
> 2.39.0
>