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

[Greg KH]

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?

And what is userspace supposed to do with this information if it sees
it?

thanks,

greg k-h