On Fri, Mar 20, 2015 at 01:08:25PM +0200, Roger Quadros wrote: > On 20/03/15 11:46, Roger Quadros wrote: > > On 20/03/15 09:18, Peter Chen wrote: > >> On Thu, Mar 19, 2015 at 04:50:31PM +0200, Roger Quadros wrote: > >>> On 19/03/15 16:09, Li Jun wrote: > >>>> On Thu, Mar 19, 2015 at 12:14:39PM +0200, Roger Quadros wrote: > >>>>> On 19/03/15 05:30, Peter Chen wrote: > >>>>>> On Wed, Mar 18, 2015 at 03:55:56PM +0200, Roger Quadros wrote: > >>>>>>> The OTG state machine needs a mechanism to start and > >>>>>>> stop the gadget controller. Add usb_gadget_start() > >>>>>>> and usb_gadget_stop(). > >>>>>>> > >>>>>>> Signed-off-by: Roger Quadros <rogerq@xxxxxx> > >>>>>>> --- > >>>>>>> drivers/usb/gadget/udc/udc-core.c | 166 +++++++++++++++++++++++++++++++++++--- > >>>>>>> include/linux/usb/gadget.h | 3 + > >>>>>>> 2 files changed, 158 insertions(+), 11 deletions(-) > >>>>>>> > >>>>>>> diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c > >>>>>>> index 5a81cb0..69b4123 100644 > >>>>>>> --- a/drivers/usb/gadget/udc/udc-core.c > >>>>>>> +++ b/drivers/usb/gadget/udc/udc-core.c > >>>>>>> @@ -35,6 +35,8 @@ > >>>>>>> * @dev - the child device to the actual controller > >>>>>>> * @gadget - the gadget. For use by the class code > >>>>>>> * @list - for use by the udc class driver > >>>>>>> + * @running - udc is running > >>>>>> > >>>>>> Doesn't OTG FSM should know it? > >>>>> > >>>>> Not really, as the gadget driver might not have been loaded yet or userspace might > >>>>> have disabled softconnect when the OTG FSM wants UDC to start. > >>>>> > >>>>> So only UDC knows if it has really started or not based on this flag. > >>>>> > >>>> > >>>> why this can not be known by check the otg fsm state? i.e. if the device in > >>>> b_peripheral or a_peripheral state, udc should had started, isn't it? > >>> > >>> If gadget function driver (which is different from UDC driver) is not yet loaded > >>> then we can't start UDC even if otg fsm is in b_peripheral. > >>> Also, if userspace has disabled softconnect we can't start UDC. > >>> > >>> So, b_peripheral != UDC_started. > >>> > >>> I've tried to address this issue by adding the checks in usb_gadget_start(). > >>> > >> > >> Ok, maybe we have different understanding for 'B-Device' at software, > >> In spec, it says the Micro-AB receptacle with nothing connected can be > >> 'B-Device', but in fact, we may not enable device mode before loading > >> gadget driver, in chipidea fsm design, if the gadget driver is not > >> loaded, the FSM will not start, and it is at OTG_STATE_UNDEFINED. > > > > Right. I mixed up into thinking that we should respect the softconnect > > while in OTG mode. It seems that we should ignore it. > > > >> > >> One more thing is we may need to find a place to issue SRP when we > >> load gadget driver, since we may at b_idle at that time due to host > >> closes the vbus (timeout for a_wait_bcon). > > > > Issuing SRP should be done by the otg-fsm and not udc-core. > > The udc-core can at the least call usb_otg_kick_fsm() after setting the gadget > > driver so that otg-fsm knows that we now have a valid gadget and can take > > necessary action. i.e. change from b_idle to b_srp_init and then to b_peripheral. > > To clarify further. Is it right to assume that OTG FSM will not be started till > both gadget UDC driver _AND_ gadget function driver are loaded? > > And it will be stopped when either of them unloads. > > This simplifies things a lot. Yes, you are right. > > cheers, > -roger > > > > >> > >> What is the "softconnect" used for? In otg fsm, we use b_bus_req for FSM. > >> > > I understand now that we shouldn't bother with softconnect when we are in OTG fsm mode. > > That solves our problem with the running flags. > > > > So now, b_peripheral == UDC_started. > > > > I will address this in v2. > > > > cheers, > > -roger > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
