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SubjectRe: [PATCH v10 5/5] usb: gadget: f_ecm: Add suspend/resume and remote wakeup support
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On 3/15/2023 2:15 PM, Thinh Nguyen wrote:
> On Wed, Mar 15, 2023, Thinh Nguyen wrote:
>> On Wed, Mar 15, 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 | 77 +++++++++++++++++++++++++++++++++++
>>> drivers/usb/gadget/function/u_ether.c | 63 ++++++++++++++++++++++++++++
>>> drivers/usb/gadget/function/u_ether.h | 4 ++
>>> 3 files changed, 144 insertions(+)
>>>
>>> diff --git a/drivers/usb/gadget/function/f_ecm.c b/drivers/usb/gadget/function/f_ecm.c
>>> index a7ab30e..fea07ab 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 +887,77 @@ 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;
>>> +}
>>> +
>>> +static int ecm_func_suspend(struct usb_function *f, u8 options)
>>> +{
>>> + struct usb_configuration *c = f->config;
>>> +
>>> + DBG(c->cdev, "func susp %u cmd\n", options);
>>> +
>>> + /* Respond with negative errno if request is not supported */
>>> + if (!(USB_CONFIG_ATT_WAKEUP & c->bmAttributes))
>>> + return -EINVAL;
>>
>> We only need to return early if the host tries to enable remote wake
>> while the device isn't capable of it:
>>
>> wakeup_sel = !!(options & (USB_INTRF_FUNC_SUSPEND_RW >> 8));
>> if (wakeup_sel && !(USB_CONFIG_ATT_WAKEUP & c->bmAttributes))
>> return -EINVAL;
>>
>> f->func_wakeup_armed = wakeup_sel;
>>
>
> Also, I notice that we can't differentiate between ClearFeature() and
> SetFeature() in f->func_suspend(). Perhaps we should handle arming the
> remote wakeup in the composite layer so we can set/clear the remote
> wake. It's common across multiple devices. It's probably better to be
> there.
>
> Thanks,
> Thinh

Yeah agree with that. We check for function_wakeup_armed flag before
sending remote wakeup in composite.c. So it makes more sense
to set/reset this flag in composite.c itself. I will make that change
and upload v12 along with fixing 'value = 0' removal that we discussed
earlier. Please let me know if that is fine

Thanks
Elson

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