[PATCH v2] usb: dwc3: Wait unconditionally after issuing EndXfer command

[PATCH v2] usb: dwc3: Wait unconditionally after issuing EndXfer command

[Prashanth K]

Currently all controller IP/revisions except DWC3_usb3 >= 310a
wait 1ms unconditionally for ENDXFER completion when IOC is not
set. This is because DWC_usb3 controller revisions >= 3.10a
supports GUCTL2[14: Rst_actbitlater] bit which allows polling
CMDACT bit to know whether ENDXFER command is completed.

Consider a case where an IN request was queued, and parallelly
soft_disconnect was called (due to ffs_epfile_release). This
eventually calls stop_active_transfer with IOC cleared, hence
send_gadget_ep_cmd() skips waiting for CMDACT cleared during
EndXfer. For DWC3 controllers with revisions >= 310a, we don't
forcefully wait for 1ms either, and we proceed by unmapping the
requests. If ENDXFER didn't complete by this time, it leads to
SMMU faults since the controller would still be accessing those
requests.

Fix this by ensuring ENDXFER completion by adding 1ms delay in
__dwc3_stop_active_transfer() unconditionally.

Cc: <stable@vger.kernel.org>
Fixes: b353eb6dc285 ("usb: dwc3: gadget: Skip waiting for CMDACT cleared during endxfer")
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
---
Changes in v2:
Changed the patch logic from CMDACT polling to 1ms mdelay.
Updated subject and commit accordingly.
Link to v1: https://lore.kernel.org/all/20240422090539.3986723-1-quic_prashk@quicinc.com/

 drivers/usb/dwc3/gadget.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 4df2661f6675..666eae94524f 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1724,8 +1724,7 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
 	dep->resource_index = 0;
 
 	if (!interrupt) {
-		if (!DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC3, 310A))
-			mdelay(1);
+		mdelay(1);
 		dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
 	} else if (!ret) {
 		dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
-- 
2.25.1

Re: [PATCH v2] usb: dwc3: Wait unconditionally after issuing EndXfer command

[Thinh Nguyen]

On Thu, Apr 25, 2024, Prashanth K wrote:
> Currently all controller IP/revisions except DWC3_usb3 >= 310a
> wait 1ms unconditionally for ENDXFER completion when IOC is not
> set. This is because DWC_usb3 controller revisions >= 3.10a
> supports GUCTL2[14: Rst_actbitlater] bit which allows polling
> CMDACT bit to know whether ENDXFER command is completed.
> 
> Consider a case where an IN request was queued, and parallelly
> soft_disconnect was called (due to ffs_epfile_release). This
> eventually calls stop_active_transfer with IOC cleared, hence
> send_gadget_ep_cmd() skips waiting for CMDACT cleared during
> EndXfer. For DWC3 controllers with revisions >= 310a, we don't
> forcefully wait for 1ms either, and we proceed by unmapping the
> requests. If ENDXFER didn't complete by this time, it leads to
> SMMU faults since the controller would still be accessing those
> requests.
> 
> Fix this by ensuring ENDXFER completion by adding 1ms delay in
> __dwc3_stop_active_transfer() unconditionally.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: b353eb6dc285 ("usb: dwc3: gadget: Skip waiting for CMDACT cleared during endxfer")
> Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
> ---
> Changes in v2:
> Changed the patch logic from CMDACT polling to 1ms mdelay.
> Updated subject and commit accordingly.
> Link to v1: https://urldefense.com/v3/__https://lore.kernel.org/all/20240422090539.3986723-1-quic_prashk@quicinc.com/__;!!A4F2R9G_pg!fa3zoJhmfdChG32lHtAa-7bxJpxPsw2wgzQwQAq9gWG2LwWyr9WnIzm9Eol6hmiKLEOTJuqjOeTYVYZ_sNnER6p_uF4$ 
> 
>  drivers/usb/dwc3/gadget.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 4df2661f6675..666eae94524f 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1724,8 +1724,7 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
>  	dep->resource_index = 0;
>  
>  	if (!interrupt) {
> -		if (!DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC3, 310A))
> -			mdelay(1);
> +		mdelay(1);
>  		dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
>  	} else if (!ret) {
>  		dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
> -- 
> 2.25.1
> 

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

Thanks,
Thinh

Re: [PATCH v2] usb: dwc3: Wait unconditionally after issuing EndXfer command

[Greg Kroah-Hartman]

On Thu, Apr 25, 2024 at 11:22:08PM +0000, Thinh Nguyen wrote:
> On Thu, Apr 25, 2024, Prashanth K wrote:
> > Currently all controller IP/revisions except DWC3_usb3 >= 310a
> > wait 1ms unconditionally for ENDXFER completion when IOC is not
> > set. This is because DWC_usb3 controller revisions >= 3.10a
> > supports GUCTL2[14: Rst_actbitlater] bit which allows polling
> > CMDACT bit to know whether ENDXFER command is completed.
> > 
> > Consider a case where an IN request was queued, and parallelly
> > soft_disconnect was called (due to ffs_epfile_release). This
> > eventually calls stop_active_transfer with IOC cleared, hence
> > send_gadget_ep_cmd() skips waiting for CMDACT cleared during
> > EndXfer. For DWC3 controllers with revisions >= 310a, we don't
> > forcefully wait for 1ms either, and we proceed by unmapping the
> > requests. If ENDXFER didn't complete by this time, it leads to
> > SMMU faults since the controller would still be accessing those
> > requests.
> > 
> > Fix this by ensuring ENDXFER completion by adding 1ms delay in
> > __dwc3_stop_active_transfer() unconditionally.
> > 
> > Cc: <stable@vger.kernel.org>
> > Fixes: b353eb6dc285 ("usb: dwc3: gadget: Skip waiting for CMDACT cleared during endxfer")
> > Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
> > ---
> > Changes in v2:
> > Changed the patch logic from CMDACT polling to 1ms mdelay.
> > Updated subject and commit accordingly.
> > Link to v1: https://urldefense.com/v3/__https://lore.kernel.org/all/20240422090539.3986723-1-quic_prashk@quicinc.com/__;!!A4F2R9G_pg!fa3zoJhmfdChG32lHtAa-7bxJpxPsw2wgzQwQAq9gWG2LwWyr9WnIzm9Eol6hmiKLEOTJuqjOeTYVYZ_sNnER6p_uF4$ 
> > 
> >  drivers/usb/dwc3/gadget.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index 4df2661f6675..666eae94524f 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -1724,8 +1724,7 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
> >  	dep->resource_index = 0;
> >  
> >  	if (!interrupt) {
> > -		if (!DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC3, 310A))
> > -			mdelay(1);
> > +		mdelay(1);
> >  		dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
> >  	} else if (!ret) {
> >  		dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
> > -- 
> > 2.25.1
> > 
> 
> Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

This patch breaks the build on my systems:

  CC [M]  drivers/usb/dwc3/gadget.o
drivers/usb/dwc3/gadget.c: In function ‘__dwc3_stop_active_transfer’:
drivers/usb/dwc3/gadget.c:1702:22: error: unused variable ‘dwc’ [-Werror=unused-variable]
 1702 |         struct dwc3 *dwc = dep->dwc;
      |                      ^~~
cc1: all warnings being treated as errors

so I can't take it :(

Re: [PATCH v2] usb: dwc3: Wait unconditionally after issuing EndXfer command

[Thinh Nguyen]

On Tue, Apr 30, 2024, Greg Kroah-Hartman wrote:
> On Thu, Apr 25, 2024 at 11:22:08PM +0000, Thinh Nguyen wrote:
> > On Thu, Apr 25, 2024, Prashanth K wrote:
> > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > > index 4df2661f6675..666eae94524f 100644
> > > --- a/drivers/usb/dwc3/gadget.c
> > > +++ b/drivers/usb/dwc3/gadget.c
> > > @@ -1724,8 +1724,7 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
> > >  	dep->resource_index = 0;
> > >  
> > >  	if (!interrupt) {
> > > -		if (!DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC3, 310A))
> > > -			mdelay(1);
> > > +		mdelay(1);
> > >  		dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
> > >  	} else if (!ret) {
> > >  		dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
> > > -- 
> > > 2.25.1
> > > 
> > 
> > Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> 
> This patch breaks the build on my systems:
> 
>   CC [M]  drivers/usb/dwc3/gadget.o
> drivers/usb/dwc3/gadget.c: In function ‘__dwc3_stop_active_transfer’:
> drivers/usb/dwc3/gadget.c:1702:22: error: unused variable ‘dwc’ [-Werror=unused-variable]
>  1702 |         struct dwc3 *dwc = dep->dwc;
>       |                      ^~~
> cc1: all warnings being treated as errors
> 
> so I can't take it :(

Thanks Greg for reporting.

Hi Prashanth,

Can you resend v3 with the build fix. You can keep my Acked-by. Also,
please help test and catch these issues early to avoid turn-around time.

Thanks,
Thinh