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. 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 > -- 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
