Hello Mathieu,
I've talked to Peng and if my understanding is correct I think the patch is OK.
Maybe we can split the patch in two:
* first, adding the power off callback with explanations.
* second, adding the restart callback with explanations.
And also add a more detailed explanation.
Power off and restart are totally different operations and are not complementary
as I thought in the beginning. There are not like suspend/resume for example.
> > static int imx_rproc_probe(struct platform_device *pdev)
> > {
> > struct device *dev = &pdev->dev;
> > @@ -1104,6 +1122,24 @@ static int imx_rproc_probe(struct platform_device *pdev)
> > if (rproc->state != RPROC_DETACHED)
> > rproc->auto_boot = of_property_read_bool(np, "fsl,auto-boot");
> >
> > + if (of_device_is_compatible(dev->of_node, "fsl,imx7ulp-cm4")) {
> > + ret = devm_register_sys_off_handler(dev, SYS_OFF_MODE_POWER_OFF_PREPARE,
> > + SYS_OFF_PRIO_DEFAULT,
> > + imx_rproc_sys_off_handler, rproc);
>
> Why does the mailbox needs to be set up again when the system is going down...
Scenario: We call Linux *shutdown -P * command to power off the machine.
At this point mailbox TX operation is configured as *blocking*. Power
off is done via
an atomic notifier call which doesn't allow blocking. If we do so we
will endup in a kernel crash.
So, at this moment we setup again the mailboxes configuring them with
*non-blocking* option.
>
> > + if (ret) {
> > + dev_err(dev, "register power off handler failure\n");
> > + goto err_put_clk;
> > + }
> > +
> > + ret = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART_PREPARE,
> > + SYS_OFF_PRIO_DEFAULT,
> > + imx_rproc_sys_off_handler, rproc);
>
> ... and why does it need to be free'd when the system is going up?
System is not going up here. System is running and we do a reboot.
Scenario: We call Linux *shutdown -r* command to reboot the machine.
Similarly, mailboxes are already set and configured as *blocking*. We
cannot use the mailboxes
as they are because reboot is done via an atomic notifier which if we
call a blocking function it will endup in crash.
So, we need to free the existing mailbox and create new ones with the
*non-blocking* options.
I think this is really fair to me. The one thing, I admit we must work
on, create a better commit message.
What do you say? Does this work for you?
Thanks a lot for your help!
