linux-kernel - Re: [PATCH 1/1] usb: dwc2: gadget: don't try to disable ep0 in dwc2_hsotg

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Message-ID: <7bef0e3b-3430-1ad1-127d-7093511b6493@foss.st.com>
Date:   Tue, 14 Dec 2021 13:53:36 +0100
From:   Amelie DELAUNAY <amelie.delaunay@...s.st.com>
To:     Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:     "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        Fabrice Gasnier <fabrice.gasnier@...s.st.com>
Subject: Re: [PATCH 1/1] usb: dwc2: gadget: don't try to disable ep0 in
 dwc2_hsotg_suspend

Hi Minas,

On 12/14/21 7:22 AM, Minas Harutyunyan wrote:
> Hi Amelie,
> 
> On 12/7/2021 5:01 PM, Amelie Delaunay wrote:
>> Calling dwc2_hsotg_ep_disable on ep0 (in/out) will lead to the following
>> logs before returning -EINVAL:
>> dwc2 49000000.usb-otg: dwc2_hsotg_ep_disable: called for ep0
>> dwc2 49000000.usb-otg: dwc2_hsotg_ep_disable: called for ep0
>>
> 
> This messages printed for EP0 OUT which can't be disabled, but EP0 IN
> can and should be disabled. Your patch exclude EP0 IN from disabling flow.


Thanks for the review. I wonder why then in dwc2_hsotg_udc_stop and 
dwc2_hsotg_core_init_disconnected EP0 IN is not disabled (loop starts 
from EP1) ?

Due to:
	/* Same dwc2_hsotg_ep is used in both directions for ep0 */
	hsotg->eps_out[0] = hsotg->eps_in[0];

the condition in dwc2_hsotg_ep_disable to display the error is always 
true for EP0, whatever the direction, so the log appears for EP0 IN & OUT:
	if (ep == &hsotg->eps_out[0]->ep) {
		dev_err(hsotg->dev, "%s: called for ep0\n", __func__);
		return -EINVAL;
	}

Should all loops need to be fixed to start loop from EP0 but exclude EP0 
OUT from being disabled, so that EP0 IN can be disabled ? e.g. for 
dwc2_hsotg_suspend:
	

$ git diff drivers/usb/dwc2/gadget.c
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 11d85a6e0b0d..0c12219bfbf4 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -4231,7 +4231,7 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)

         dev_dbg(hsotg->dev, "%s(ep %p)\n", __func__, ep);

-       if (ep == &hsotg->eps_out[0]->ep) {
+       if (ep == &hsotg->eps_out[0]->ep && !dir_in) {
                 dev_err(hsotg->dev, "%s: called for ep0\n", __func__);
                 return -EINVAL;
         }
@@ -5077,7 +5077,7 @@ int dwc2_hsotg_suspend(struct dwc2_hsotg *hsotg)
                 for (ep = 0; ep < hsotg->num_of_eps; ep++) {
                         if (hsotg->eps_in[ep])
 
dwc2_hsotg_ep_disable_lock(&hsotg->eps_in[ep]->ep);
-                       if (hsotg->eps_out[ep])
+                       if (ep > 0 && hsotg->eps_out[ep])
 
dwc2_hsotg_ep_disable_lock(&hsotg->eps_out[ep]->ep);
                 }
         }

Regards,
Amelie

> 
> Thanks,
> Minas
> 
>> To avoid these two logs while suspending, start disabling the endpoint
>> from the index 1, as done in dwc2_hsotg_udc_stop:
>>
>> 	/* all endpoints should be shutdown */
>> 	for (ep = 1; ep < hsotg->num_of_eps; ep++) {
>> 		if (hsotg->eps_in[ep])
>> 			dwc2_hsotg_ep_disable_lock(&hsotg->eps_in[ep]->ep);
>> 		if (hsotg->eps_out[ep])
>> 			dwc2_hsotg_ep_disable_lock(&hsotg->eps_out[ep]->ep);
>> 	}
>>
>> Signed-off-by: Amelie Delaunay <amelie.delaunay@...s.st.com>
>> ---
>>    drivers/usb/dwc2/gadget.c | 2 +-
>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
>> index b884a83b26a6..ee31f9a328da 100644
>> --- a/drivers/usb/dwc2/gadget.c
>> +++ b/drivers/usb/dwc2/gadget.c
>> @@ -5086,7 +5086,7 @@ int dwc2_hsotg_suspend(struct dwc2_hsotg *hsotg)
>>    		hsotg->gadget.speed = USB_SPEED_UNKNOWN;
>>    		spin_unlock_irqrestore(&hsotg->lock, flags);
>>    
>> -		for (ep = 0; ep < hsotg->num_of_eps; ep++) {
>> +		for (ep = 1; ep < hsotg->num_of_eps; ep++) {
>>    			if (hsotg->eps_in[ep])
>>    				dwc2_hsotg_ep_disable_lock(&hsotg->eps_in[ep]->ep);
>>    			if (hsotg->eps_out[ep])
>