Re: kexec on rk3399

[Vicente Bergas]

On Wednesday, August 14, 2019 3:06:04 PM CEST, Felipe Balbi wrote:
> Hi,
>
> Vicente Bergas <vicencb@xxxxxxxxx> writes:
> > On Monday, July 22, 2019 4:31:27 PM CEST, Vicente Bergas wrote:
> > > Hi, i have been running linux on rk3399 booted with kexec fine until 5.2
> > > From 5.2 onwards, there are memory corruption issues as reported here:
> > > http://lkml.iu.edu/hypermail/linux/kernel/1906.2/07211.html
> > > kexec has been identified as the principal reason for the issues.
> > >
> > > It turns out that kexec has never worked reliably on this platform, ...
> >
> > Thank you all for your suggestions on where the issue could be.
> >
> > It seems that it was the USB driver.
> > Now using v5.2.8 booted with kexec from v5.2.8 with a workaround and
> > so far so good. It is being tested on the Sapphire board.
> >
> > The workaround is:
> > --- a/drivers/usb/dwc3/dwc3-of-simple.c
> > +++ b/drivers/usb/dwc3/dwc3-of-simple.c
> > @@ -133,6 +133,13 @@
> >  	return 0;
> >  }
> >  
> > +static void dwc3_of_simple_shutdown(struct platform_device *pdev)
> > +{
> > +	struct dwc3_of_simple *simple = platform_get_drvdata(pdev);
> > +
> > +	reset_control_assert(simple->resets);
> > +}
> > +
> >  static int __maybe_unused dwc3_of_simple_runtime_suspend(struct device 
> > *dev)
> >  {
> >  	struct dwc3_of_simple	*simple = dev_get_drvdata(dev);
> > @@ -190,6 +197,7 @@
> >  static struct platform_driver dwc3_of_simple_driver = {
> >  	.probe		= dwc3_of_simple_probe,
> >  	.remove		= dwc3_of_simple_remove,
> > +	.shutdown	= dwc3_of_simple_shutdown,
> >  	.driver		= {
> >  		.name	= "dwc3-of-simple",
> >  		.of_match_table = of_dwc3_simple_match,
> >
> > If this patch is OK after review i can resubmit it as a pull request.
>
> not a pull request, just send a patch using git send-email
>
> > Should a similar change be applied to drivers/usb/dwc3/core.c ?
>
> Is it necessary? We haven't had any bug reports regarding that. Also, if
> we have reset control support in the core driver, why do we need it in
> of_simple? Seems like of_simple could just rely on what core does.

the workaround has been tested patching only core.c with
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1561,6 +1561,13 @@
	return 0;
}

+static void dwc3_shutdown(struct platform_device *pdev)
+{
+	struct dwc3 *dwc = platform_get_drvdata(pdev);
+
+	reset_control_assert(dwc->reset);
+}
+
#ifdef CONFIG_PM
static int dwc3_core_init_for_resume(struct dwc3 *dwc)
{
@@ -1866,6 +1873,7 @@
static struct platform_driver dwc3_driver = {
	.probe		= dwc3_probe,
	.remove		= dwc3_remove,
+	.shutdown	= dwc3_shutdown,
	.driver		= {
		.name	= "dwc3",
		.of_match_table	= of_match_ptr(of_dwc3_match),

and leaving dwc3-of-simple.c as is, the issue persisted.

Regards,
 VicenÃ.