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

Buddhabhatti, Jay
2023-10-04T12:48:32Z

Hi Greg,

> -----Original Message-----
> From: Greg KH <gregkh@linuxfoundation.org>
> Sent: Wednesday, October 4, 2023 5:45 PM
> To: Buddhabhatti, Jay <jay.buddhabhatti@amd.com>
> Cc: Simek, Michal <michal.simek@amd.com>; Shah, Tanmay
> <tanmay.shah@amd.com>; Manne, Nava kishore
> <nava.kishore.manne@amd.com>; Levinsky, Ben <ben.levinsky@amd.com>;
> robh@kernel.org; dhaval.r.shah@amd.com; marex@denx.de; Shaikh, Izhar
> Ameer <izhar.ameer.shaikh@amd.com>; arnd@arndb.de;
> ruanjinjie@huawei.com; mathieu.poirier@linaro.org; linux-
> kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org
> 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@amd.com>
> > Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
> > Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@amd.com>
> > ---
> > 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