RE: [PATCH v2 4/6] drivers: soc: xilinx: Fix error message on SGI registration failure

[Buddhabhatti, Jay]

Hi Greg,

> -----Original Message-----
> From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, October 4, 2023 5:45 PM
> To: Buddhabhatti, Jay <jay.buddhabhatti@xxxxxxx>
> Cc: Simek, Michal <michal.simek@xxxxxxx>; Shah, Tanmay
> <tanmay.shah@xxxxxxx>; Manne, Nava kishore
> <nava.kishore.manne@xxxxxxx>; Levinsky, Ben <ben.levinsky@xxxxxxx>;
> robh@xxxxxxxxxx; dhaval.r.shah@xxxxxxx; marex@xxxxxxx; Shaikh, Izhar
> Ameer <izhar.ameer.shaikh@xxxxxxx>; arnd@xxxxxxxx;
> ruanjinjie@xxxxxxxxxx; mathieu.poirier@xxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 4/6] drivers: soc: xilinx: Fix error message on SGI
> registration failure
> 
> On Wed, Oct 04, 2023 at 02:41:14AM -0700, Jay Buddhabhatti wrote:
> > Failure to register SGI for firmware event notification is non-fatal
> > error when feature is not supported by other modules such as Xen and
> > TF-A. Add _info level log message for such special case.
> >
> > Also add XST_PM_INVALID_VERSION error code and map it to -EOPNOSUPP
> > Linux kernel error code. If feature is not supported or EEMI API
> > version is mismatch, firmware can return XST_PM_INVALID_VERSION = 4 or
> > XST_PM_NO_FEATURE = 19 error code.
> >
> > Co-developed-by: Tanmay Shah <tanmay.shah@xxxxxxx>
> > Signed-off-by: Tanmay Shah <tanmay.shah@xxxxxxx>
> > Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@xxxxxxx>
> > ---
> >  drivers/firmware/xilinx/zynqmp.c        | 4 +++-
> >  drivers/soc/xilinx/xlnx_event_manager.c | 7 ++++++-
> >  include/linux/firmware/xlnx-zynqmp.h    | 1 +
> >  3 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/firmware/xilinx/zynqmp.c
> > b/drivers/firmware/xilinx/zynqmp.c
> > index 00ea2508f692..de09d77cf1e4 100644
> > --- a/drivers/firmware/xilinx/zynqmp.c
> > +++ b/drivers/firmware/xilinx/zynqmp.c
> > @@ -92,6 +92,8 @@ static int zynqmp_pm_ret_code(u32 ret_status)
> >  		return 0;
> >  	case XST_PM_NO_FEATURE:
> >  		return -ENOTSUPP;
> > +	case XST_PM_INVALID_VERSION:
> > +		return -EOPNOTSUPP;
> >  	case XST_PM_NO_ACCESS:
> >  		return -EACCES;
> >  	case XST_PM_ABORT_SUSPEND:
> > @@ -379,7 +381,7 @@ int zynqmp_pm_register_sgi(u32 sgi_num, u32 reset)
> >
> >  	ret = zynqmp_pm_invoke_fn(TF_A_PM_REGISTER_SGI, sgi_num, reset,
> 0, 0,
> >  				  0, NULL);
> > -	if (!ret)
> > +	if (ret != -EOPNOTSUPP && !ret)
> >  		return ret;
> >
> >  	/* try old implementation as fallback strategy if above fails */
> > diff --git a/drivers/soc/xilinx/xlnx_event_manager.c
> > b/drivers/soc/xilinx/xlnx_event_manager.c
> > index 38cfc161a713..bfa5cf4a0cab 100644
> > --- a/drivers/soc/xilinx/xlnx_event_manager.c
> > +++ b/drivers/soc/xilinx/xlnx_event_manager.c
> > @@ -653,7 +653,12 @@ static int xlnx_event_manager_probe(struct
> > platform_device *pdev)
> >
> >  	ret = zynqmp_pm_register_sgi(sgi_num, 0);
> >  	if (ret) {
> > -		dev_err(&pdev->dev, "SGI %d Registration over TF-A failed with
> %d\n", sgi_num, ret);
> > +		if (ret == -EOPNOTSUPP)
> > +			dev_info(&pdev->dev, "PM firmware event notification
> not
> > +supported\n");
> 
> Why is this "info"?  Why not error?
[Jay] Because it is non-fatal error which will not cause kernel crash.

> 
> And what is userspace supposed to do with this information if it sees it?
[Jay] This message indicates that SGI registration is not supported by other modules like TF-A or Xen. So user need to use TF-A with this support if they want to use event management driver.

Thanks,
Jay
> 
> thanks,
> 
> greg k-h