Messages in this thread | | | Date | Mon, 20 Mar 2023 10:42:09 -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 7:26 PM, Thinh Nguyen wrote: > On Fri, Mar 17, 2023, Elson Serrao wrote: >> >> >> 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. > > Ok. So do you plan to update composite_resume to check that? Perhaps > document this expected behavior also? > Yes I will update composite resume to handle this scenario. I was handling it in f_ecm till now, but based on this new discussion I will move all handling to composite layer. >> >> Please let me know if you see any alternative or better approach here. >> > > If we have a use for it in composite.c, then it should be made > available. Otherwise it should only exist in the function driver (ie. in > f_ecm structure). > Yes I will keep it for now. Since we are moving all handling to composite layer better to have some kind of flag that function drivers/composite layer can use to check if a given function is in FUNCTION_SUSPEND state or composite_suspend() state.
Thanks Elson
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