Messages in this thread | | | Date | Fri, 17 Mar 2023 17:23:28 -0700 | Subject | Re: [PATCH v12 6/6] usb: gadget: f_ecm: Add suspend/resume and remote wakeup support | From | Elson Serrao <> |
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On 3/17/2023 4:20 PM, Thinh Nguyen wrote: > On Fri, Mar 17, 2023, Thinh Nguyen wrote: >> On Fri, Mar 17, 2023, Elson Serrao wrote: >>> >>> >>> On 3/16/2023 5:11 PM, Thinh Nguyen wrote: >>>> On Thu, Mar 16, 2023, Elson Roy Serrao wrote: >>>>> When host sends a suspend notification to the device, handle >>>>> the suspend callbacks in the function driver. Enhanced super >>>>> speed devices can support function suspend feature to put the >>>>> function in suspend state. Handle function suspend callback. >>>>> >>>>> Depending on the remote wakeup capability the device can either >>>>> trigger a remote wakeup or wait for the host initiated resume to >>>>> start data transfer again. >>>>> >>>>> Signed-off-by: Elson Roy Serrao <quic_eserrao@quicinc.com> >>>>> --- >>>>> drivers/usb/gadget/function/f_ecm.c | 71 +++++++++++++++++++++++++++++++++++ >>>>> drivers/usb/gadget/function/u_ether.c | 63 +++++++++++++++++++++++++++++++ >>>>> drivers/usb/gadget/function/u_ether.h | 4 ++ >>>>> 3 files changed, 138 insertions(+) >>>>> >>>>> diff --git a/drivers/usb/gadget/function/f_ecm.c b/drivers/usb/gadget/function/f_ecm.c >>>>> index a7ab30e..c43cd557 100644 >>>>> --- a/drivers/usb/gadget/function/f_ecm.c >>>>> +++ b/drivers/usb/gadget/function/f_ecm.c >>>>> @@ -633,6 +633,8 @@ static void ecm_disable(struct usb_function *f) >>>>> usb_ep_disable(ecm->notify); >>>>> ecm->notify->desc = NULL; >>>>> + f->func_suspended = false; >>>>> + f->func_wakeup_armed = false; >>>>> } >>>>> /*-------------------------------------------------------------------------*/ >>>>> @@ -885,6 +887,71 @@ static struct usb_function_instance *ecm_alloc_inst(void) >>>>> return &opts->func_inst; >>>>> } >>>>> +static void ecm_suspend(struct usb_function *f) >>>>> +{ >>>>> + struct f_ecm *ecm = func_to_ecm(f); >>>>> + struct usb_composite_dev *cdev = ecm->port.func.config->cdev; >>>>> + >>>>> + if (f->func_suspended) { >>>>> + DBG(cdev, "Function already suspended\n"); >>>>> + return; >>>>> + } >>>>> + >>>>> + DBG(cdev, "ECM Suspend\n"); >>>>> + >>>>> + gether_suspend(&ecm->port); >>>>> +} >>>>> + >>>>> +static void ecm_resume(struct usb_function *f) >>>>> +{ >>>>> + struct f_ecm *ecm = func_to_ecm(f); >>>>> + struct usb_composite_dev *cdev = ecm->port.func.config->cdev; >>>>> + >>>>> + /* >>>>> + * If the function is in USB3 Function Suspend state, resume is >>>>> + * canceled. In this case resume is done by a Function Resume request. >>>>> + */ >>>>> + if (f->func_suspended) >>>>> + return; >>>>> + >>>>> + DBG(cdev, "ECM Resume\n"); >>>>> + >>>>> + gether_resume(&ecm->port); >>>>> +} >>>>> + >>>>> +static int ecm_get_status(struct usb_function *f) >>>>> +{ >>>>> + struct usb_configuration *c = f->config; >>>>> + >>>>> + /* D0 and D1 bit set to 0 if device is not wakeup capable */ >>>>> + if (!(USB_CONFIG_ATT_WAKEUP & c->bmAttributes)) >>>>> + return 0; >>>>> + >>>>> + return (f->func_wakeup_armed ? USB_INTRF_STAT_FUNC_RW : 0) | >>>>> + USB_INTRF_STAT_FUNC_RW_CAP; >>>>> +} >>>> >>>> Why do we need to implement ecm_get_status if it's already handled in >>>> composite.c now? >>>> >>> >>> Yes this can be removed now. Will modify accordingly. >>>>> + >>>>> +static int ecm_func_suspend(struct usb_function *f, u8 options) >>>>> +{ >>>>> + struct usb_composite_dev *cdev = f->config->cdev; >>>>> + >>>>> + DBG(cdev, "func susp %u cmd\n", options); >>>>> + >>>>> + if (options & (USB_INTRF_FUNC_SUSPEND_LP >> 8)) { >>>> >>>> This feature selector doesn't indicate whether it's SetFeature or >>>> ClearFeature request. ecm_func_suspend is supposed to be for >>>> SetFeature(suspend) only. Perhaps we may have to define func_resume() >>>> for ClearFeature(suspend)? >>>> >> >>> Host uses the same feature selector FUNCTION_SUSPEND for function suspend >>> and function resume and func_suspend() callback can be used to >>> handle both the cases ? The distinction comes whether it is a >> >> How do you plan to handle that? Pass this info in some unused/reserved >> bit of the "options" argument? Introduce a new parameter to the >> func_suspend()? >> >> If that's the case, then you need to update the document on >> func_suspend() to also support ClearFeature(suspend). Right now it's >> documented for SetFeature only. Also, make sure that other existing >> function drivers will not break because of the change of the >> func_suspend behavior. >> >>> SetFeature(FUNCTION_SUSPEND) or ClearFeature(FUNCTION_SUSPEND) which can be >>> easily done in the func_suspend callback itself. We can add another callback >>> func_resume specific to ClearFeature(FUNCTION_SUSPEND) but wont that be >>> redundant and more callback handling on function driver/composite side as >>> well? Please let me know your opinion. >>> >> >> We actually didn't properly define func_suspend and its counter part. It >> seems cleaner to me to introduce func_resume as it seems more intuitive >> and easier to read. Let me know how you plan to use func_suspend() for >> both cases. >> > > How about we handle function suspend resume in composite also? I mean > something like this: > > diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c > index 36add1879ed2..79dc055eb5f7 100644 > --- a/drivers/usb/gadget/composite.c > +++ b/drivers/usb/gadget/composite.c > @@ -1948,9 +1948,18 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) > f = cdev->config->interface[intf]; > if (!f) > break; > - status = f->get_status ? f->get_status(f) : 0; > - if (status < 0) > - break; > + > + if (f->get_status) { > + status = f->get_status(f); > + if (status < 0) > + break; > + } else { > + if (f->config->bmAttributes & USB_CONFIG_ATT_WAKEUP) { > + status |= USB_INTRF_STAT_FUNC_RW_CAP; > + if (f->func_wakeup_armed) > + status |= USB_INTRF_STAT_FUNC_RW; > + } > + } > put_unaligned_le16(status & 0x0000ffff, req->buf); > break; > /* > @@ -1971,9 +1980,28 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) > f = cdev->config->interface[intf]; > if (!f) > break; > + if (w_index & USB_INTRF_FUNC_SUSPEND_RW) { > + if (!(f->config->bmAttributes & USB_CONFIG_ATT_WAKEUP)) > + break; > + > + f->func_wakeup_armed = (ctrl->bRequest == USB_REQ_SET_FEATURE); > + } > + > value = 0; > - if (f->func_suspend) > + if (f->func_suspend) { > value = f->func_suspend(f, w_index >> 8); > + } else if (w_index & USB_INTRF_FUNC_SUSPEND_LP) { > + if (f->suspend && && !f->func_suspended && > + ctrl->bRequest == USB_REQ_SET_FEATURE)) { > + f->suspend(f); > + f->func_suspended = true; > + } else if (f->resume && f->func_suspended && > + ctrl->bRequest == USB_REQ_CLEAR_FEATURE_FEATURE)) { > + f->resume(f); > + f->func_suspended = false; > + } > + } > + > if (value < 0) { > ERROR(cdev, > "func_suspend() returned error %d\n", > At individual function driver level there is no need to differentiate between suspend() and func_suspend() APIs, as both are intended to put the function in suspend state. So your idea/implementation above makes it much more clearer. Let composite also handle this and call either f->suspend() or f->resume() callback based on the setup packet received. Thank you for this suggestion.
> > Also, do we need the f->func_suspended flag? we'd need the remote wakeup > flag for the status, but when do we need f->func_suspended? It seems > like it can be handled within the function driver's scope.
f->func_suspended flag I had added for below purposes
1.) Function drivers should know the right wakeup() op to be called. That is if they are in FUNC_SUSPEND then call usb_func_wakeup() and if they are in device suspend then call usb_gadget_wakeup(). (we can use f->func_wakeup_armed flag for this purpose as well)
2.) If a function is in USB3 FUNCTION_SUSPEND state then it shouldn't allow f->resume() called through composite_resume() as the exit from FUNCTION_SUSPEND state is via ClearFeature(FUNCTION_SUSPEND).
So we need a way to tell function drivers if they are in USB3 FUNCTION_SUSPEND state OR device suspend.
Please let me know if you see any alternative or better approach here.
Thanks Elson
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