Re: [PATCH 2/3] platform/x86: ISST : Check major minor version

[Ilpo Järvinen]

On Mon, 25 Sep 2023, Srinivas Pandruvada wrote:

> Parse major and minor version number from the version field. If there
> is a mismatch for major version, exit from further processing for that
> domain.
> 
> If there is mismatch in minor version, driver continue to process with
> an error message.

This sentence sounds odd.

> Minor version change doesn't change offsets and bit
> structures of TPMI fields.
> 
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
> ---
>  .../x86/intel/speed_select_if/isst_tpmi_core.c   | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> index 63faa2ea8327..37f17e229419 100644
> --- a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> +++ b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> @@ -30,7 +30,8 @@
>  #include "isst_if_common.h"
>  
>  /* Supported SST hardware version by this driver */
> -#define ISST_HEADER_VERSION		1
> +#define ISST_MAJOR_VERSION	0
> +#define ISST_MINOR_VERSION	1
>  
>  /*
>   * Used to indicate if value read from MMIO needs to get multiplied
> @@ -352,12 +353,19 @@ static int sst_main(struct auxiliary_device *auxdev, struct tpmi_per_power_domai
>  	pd_info->sst_header.cp_offset *= 8;
>  	pd_info->sst_header.pp_offset *= 8;
>  
> -	if (pd_info->sst_header.interface_version != ISST_HEADER_VERSION) {
> -		dev_err(&auxdev->dev, "SST: Unsupported version:%x\n",
> -			pd_info->sst_header.interface_version);
> +	if (pd_info->sst_header.interface_version == TPMI_VERSION_INVALID)
> +		return -ENODEV;
> +
> +	if (TPMI_MAJOR_VERSION(pd_info->sst_header.interface_version) != ISST_MAJOR_VERSION) {
> +		dev_err(&auxdev->dev, "SST: Unsupported major version:%lx\n",
> +			TPMI_MAJOR_VERSION(pd_info->sst_header.interface_version));
>  		return -ENODEV;
>  	}
>  
> +	if (TPMI_MINOR_VERSION(pd_info->sst_header.interface_version) != ISST_MINOR_VERSION)
> +		dev_err(&auxdev->dev, "SST: Ignore: Unsupported minor version:%lx\n",
> +			TPMI_MINOR_VERSION(pd_info->sst_header.interface_version));

Why is this dev_err(), wouldn't dev_info() be more appropriate since 
after this patch it's no longer an error?

> +
>  	/* Read SST CP Header */
>  	*((u64 *)&pd_info->cp_header) = readq(pd_info->sst_base + pd_info->sst_header.cp_offset);
>  
> 

-- 
 i.