Re: AM5749: tty serial 8250 omap driver crash

[Tony Lindgren <tony@atomide.com>]

* Romain Naour <romain.naour@smile.fr> [220216 09:04]:
> Hello,
> 
> Le 14/02/2022 à 14:08, Tony Lindgren a écrit :
> > * Tony Lindgren <tony@atomide.com> [220214 07:43]:
> >> Looks like the following script to just toggle the module state locks
> >> up things for me on beagle-x15 very fast. So yeah now I'm able to
> >> reproduce the issue. Seems like the module is not ready right after
> >> enabling it live we've seen for dra7 iva for example.
> > 
> > Looks like the following patch is also needed for uarts to avoid unbind
> > clock_unprepare warnings. But even with this patch dra7 uarts won't behave.
> > On unbind, there will be a clock "l4per-clkctrl:0128:0: failed to disable"
> > warning. Looks like after that any following clock enable does not seem to
> > work and that will cause the register access errors.
> > 
> > Looks like this is a dra7 specific issue as a similar test script on omap4
> > duovero keeps on going instead.
> 
> Thanks for the help and the patch!
> 
> I removed my patch removing the quirk and applied you patch but I can still
> reproduce the issue.

Yeah issues still exists for sure, looks like also omap4 fails but it just
takes a while to produce the clkctrl disable error. And remove for 8250_omap
is incomplete..

Below is a patch that makes the rebind of kernel serial console behave for me
together with the ti-sysc patch.

Additionally I also need to disable dma for now with:

&uart3 {
	/delete-property/ dma-names;
};

> Do you need some info about the kernel configuration?

Not really but if you can please test again with the ti-sysc patch,
8250_omap patch and with your serdev uart dma disabled with
delete-property?

Regards,

Tony

8< -----------------
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -1475,10 +1475,15 @@ static int omap8250_probe(struct platform_device *pdev)
 static int omap8250_remove(struct platform_device *pdev)
 {
 	struct omap8250_priv *priv = platform_get_drvdata(pdev);
+	struct uart_8250_port *up = serial8250_get_port(priv->line);
 
+	pm_runtime_resume_and_get(&pdev->dev);
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	dev_pm_clear_wake_irq(&pdev->dev);
+	cancel_work_sync(&priv->qos_work);
+	cancel_delayed_work(&up->overrun_backoff);
 	serial8250_unregister_port(priv->line);
 	cpu_latency_qos_remove_request(&priv->pm_qos_request);
 	device_init_wakeup(&pdev->dev, false);