netdev - Re: [PATCH net-next v3 02/12] net: wwan: t7xx: Add core components

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Message-ID: <5b15709f-cbc6-d922-1151-4543dc5ffc1d@linux.intel.com>
Date:   Wed, 12 Jan 2022 13:58:17 -0800
From:   "Martinez, Ricardo" <ricardo.martinez@...ux.intel.com>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:     netdev@...r.kernel.org, linux-wireless@...r.kernel.org,
        kuba@...nel.org, davem@...emloft.net, johannes@...solutions.net,
        ryazanov.s.a@...il.com, loic.poulain@...aro.org,
        m.chetan.kumar@...el.com, chandrashekar.devegowda@...el.com,
        linuxwwan@...el.com, chiranjeevi.rapolu@...ux.intel.com,
        haijun.liu@...iatek.com, amir.hanania@...el.com,
        andriy.shevchenko@...ux.intel.com, dinesh.sharma@...el.com,
        eliot.lee@...el.com, mika.westerberg@...ux.intel.com,
        moises.veleta@...el.com, pierre-louis.bossart@...el.com,
        muralidharan.sethuraman@...el.com, Soumya.Prakash.Mishra@...el.com,
        sreehari.kancharla@...el.com
Subject: Re: [PATCH net-next v3 02/12] net: wwan: t7xx: Add core components


On 12/16/2021 3:55 AM, Ilpo Järvinen wrote:
...
>
>> +	switch (reason) {
>> +	case EXCEPTION_HS_TIMEOUT:
>> +		dev_err(dev, "BOOT_HS_FAIL\n");
>> +		break;
>> +
>> +	case EXCEPTION_EVENT:
>> +		t7xx_fsm_broadcast_state(ctl, MD_STATE_EXCEPTION);
>> +		t7xx_md_exception_handshake(ctl->md);
>> +
>> +		cnt = 0;
>> +		while (cnt < FSM_MD_EX_REC_OK_TIMEOUT_MS / FSM_EVENT_POLL_INTERVAL_MS) {
>> +			if (kthread_should_stop())
>> +				return;
>> +
>> +			spin_lock_irqsave(&ctl->event_lock, flags);
>> +			event = list_first_entry_or_null(&ctl->event_queue,
>> +							 struct t7xx_fsm_event, entry);
>> +			if (event) {
>> +				if (event->event_id == FSM_EVENT_MD_EX) {
>> +					fsm_del_kf_event(event);
>> +				} else if (event->event_id == FSM_EVENT_MD_EX_REC_OK) {
>> +					rec_ok = true;
>> +					fsm_del_kf_event(event);
>> +				}
>> +			}
>> +
>> +			spin_unlock_irqrestore(&ctl->event_lock, flags);
>> +			if (rec_ok)
>> +				break;
>> +
>> +			cnt++;
>> +			/* Try again after 20ms */
>> +			msleep(FSM_EVENT_POLL_INTERVAL_MS);
>> +		}
>> +
>> +		cnt = 0;
>> +		while (cnt < FSM_MD_EX_PASS_TIMEOUT_MS / FSM_EVENT_POLL_INTERVAL_MS) {
>> +			if (kthread_should_stop())
>> +				return;
>> +
>> +			spin_lock_irqsave(&ctl->event_lock, flags);
>> +			event = list_first_entry_or_null(&ctl->event_queue,
>> +							 struct t7xx_fsm_event, entry);
>> +			if (event && event->event_id == FSM_EVENT_MD_EX_PASS) {
>> +				pass = true;
>> +				fsm_del_kf_event(event);
>> +			}
>> +
>> +			spin_unlock_irqrestore(&ctl->event_lock, flags);
>> +
>> +			if (pass)
>> +				break;
>> +			cnt++;
>> +			/* Try again after 20ms */
>> +			msleep(FSM_EVENT_POLL_INTERVAL_MS);
>> +		}
> It hurts me a bit to see so much code duplication with only that one
> extra if branch + if condition right-hand sides being different. It would
> seem like something that could be solved with a helper taking those two
> things as parameters.
>
> I hope the ordering of FSM_EVENT_MD_EX, FSM_EVENT_MD_EX_REC_OK, and
> FSM_EVENT_MD_EX_PASS is guaranteed by something. Otherwise, the event
> being waited for might not become the first entry in the event_queue and
> the loop just keeps waiting until timeout?
>
Ordering is guaranteed by the modem. Removing code duplication in the 
next iteration.

>> +void t7xx_fsm_clr_event(struct t7xx_fsm_ctl *ctl, enum t7xx_fsm_event_state event_id)
>> +{
>> +       struct device *dev = &ctl->md->t7xx_dev->pdev->dev;
>> +       struct t7xx_fsm_event *event, *evt_next;
>> +       unsigned long flags;
>> +
>> +       spin_lock_irqsave(&ctl->event_lock, flags);
>> +       list_for_each_entry_safe(event, evt_next, &ctl->event_queue, entry) {
>> +               dev_err(dev, "Unhandled event %d\n", event->event_id);
>> +
>> +               if (event->event_id == event_id)
>> +                       fsm_del_kf_event(event);
>> +       }
> It seems that only events matching to event_id are removed from the
> event_queue. Can that dev_err print the same event over and over again
> (I'm assuming here multiple calls to t7xx_fsm_clr_event can occur) because
> the other events still remaining in event_queue?
>
The purpose of this function is just to remove an event if present, it 
is not relevant if there

were other events in the list, so I'll remove the dev_err.