Re: [PATCH] usb: dwc3: Wait for EndXfer completion before restoring GUSB2PHYCFG

[Thinh Nguyen]

On Tue, Sep 24, 2024, Prashanth K wrote:
> DWC3 programming guide mentions that when operating in USB2.0 speeds,
> if GUSB2PHYCFG[6] or GUSB2PHYCFG[8] is set, it must be cleared prior
> to issuing commands and may be set again  after the command completes.
> But currently while issuing EndXfer command without CmdIOC set, we
> wait for 1ms after GUSB2PHYCFG is restored. This results in cases
> where EndXfer command doesn't get completed and causes SMMU faults
> since requests are unmapped afterwards. Hence restore GUSB2PHYCFG
> after waiting for EndXfer command completion.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 1d26ba0944d3 ("usb: dwc3: Wait unconditionally after issuing EndXfer command")
> Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
> ---
>  drivers/usb/dwc3/gadget.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 291bc549935b..50772d611582 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -438,6 +438,10 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd,
>  			dwc3_gadget_ep_get_transfer_index(dep);
>  	}
>  
> +	if (DWC3_DEPCMD_CMD(cmd) == DWC3_DEPCMD_ENDTRANSFER &&
> +	    !(cmd & DWC3_DEPCMD_CMDIOC))
> +		mdelay(1);
> +
>  	if (saved_config) {
>  		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
>  		reg |= saved_config;
> @@ -1715,12 +1719,10 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
>  	WARN_ON_ONCE(ret);
>  	dep->resource_index = 0;
>  
> -	if (!interrupt) {
> -		mdelay(1);
> +	if (!interrupt)
>  		dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
> -	} else if (!ret) {
> +	else if (!ret)
>  		dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
> -	}
>  
>  	dep->flags &= ~DWC3_EP_DELAY_STOP;
>  	return ret;
> -- 
> 2.25.1
> 

Looks good to me!

Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>

Thanks for the fix,
Thinh