Re: [PATCH] USB: initialize struct otg_fsm earlier

["Peter Chen (CIX)" <peter.chen@kernel.org>]

On 25-04-21 11:15:37, Dmitry Osipenko wrote:
> 21.04.2025 04:45, Peter Chen (CIX) пишет:
> > On 25-04-17 13:14:54, Oliver Neukum wrote:
> >> The earlier fix bf88fef0b6f1 ("usb: otg-fsm: Fix hrtimer list
> >> corruption") in effect hid an issue with intialization.
> >> In effect it replaces the racy continous reinitialization
> >> of fsm->hnp_polling_work with a delayed one-time
> >> initialization.
> >>
> >> This just makes no sense. As a single initialization
> >> is sufficient, the clean solution is just to do it once
> >> and do it early enough.
> >>
> >> Signed-off-by: Oliver Neukum <oneukum@suse.com>
> > 
> > Add Dmitry.
> > 
> > I am okay for this change, and see what's the Dmitry's response.
> 
> Thanks for notifying me
> 
> > Peter
> >> ---
> >>  drivers/usb/common/usb-otg-fsm.c | 7 +------
> >>  drivers/usb/phy/phy-fsl-usb.c    | 1 +
> >>  include/linux/usb/otg-fsm.h      | 2 +-
> >>  3 files changed, 3 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/usb/common/usb-otg-fsm.c b/drivers/usb/common/usb-otg-fsm.c
> >> index e11803225775..a22d536ccdf8 100644
> >> --- a/drivers/usb/common/usb-otg-fsm.c
> >> +++ b/drivers/usb/common/usb-otg-fsm.c
> >> @@ -117,7 +117,7 @@ static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
> >>  	}
> >>  }
> >>  
> >> -static void otg_hnp_polling_work(struct work_struct *work)
> >> +void otg_hnp_polling_work(struct work_struct *work)
> >>  {
> >>  	struct otg_fsm *fsm = container_of(to_delayed_work(work),
> >>  				struct otg_fsm, hnp_polling_work);
> >> @@ -193,11 +193,6 @@ static void otg_start_hnp_polling(struct otg_fsm *fsm)
> >>  	if (!fsm->host_req_flag)
> >>  		return;
> >>  
> >> -	if (!fsm->hnp_work_inited) {
> >> -		INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
> >> -		fsm->hnp_work_inited = true;
> >> -	}
> >> -
> >>  	schedule_delayed_work(&fsm->hnp_polling_work,
> >>  					msecs_to_jiffies(T_HOST_REQ_POLL));
> >>  }
> >> diff --git a/drivers/usb/phy/phy-fsl-usb.c b/drivers/usb/phy/phy-fsl-usb.c
> >> index 40ac68e52cee..7f0fdba689de 100644
> >> --- a/drivers/usb/phy/phy-fsl-usb.c
> >> +++ b/drivers/usb/phy/phy-fsl-usb.c
> >> @@ -845,6 +845,7 @@ int usb_otg_start(struct platform_device *pdev)
> >>  
> >>  	/* Initialize the state machine structure with default values */
> >>  	SET_OTG_STATE(otg_trans, OTG_STATE_UNDEFINED);
> >> +	INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
> >>  	fsm->otg = p_otg->phy.otg;
> 
> The original problem was fixed for the ChipIdea driver in the common USB
> code, while this phy-fsl-usb is the Freeescale USB driver that has
> nothing to do with the ChipIdea and the common code, AFAICT. Hence this
> patch should be wrong. I suggest not to change the original logic.
> 

Thanks for confirming it.  I did not check the user for OTG FSM
carefully since there are no active users long time.

I have checked that the phy-fsl-usb has not used hnp polling,
and the fsm->host_req_flag is not allocated. The chipidea driver is
the only user for hnp polling, so this patch is not needed.

By the way, I just curious that are there any products in market still
use OTG FSM?

-- 

Best regards,
Peter