Re: [Intel-wired-lan] [PATCH iwl-net v1 1/1] e1000e: set fixed clock frequency indication for Nahum 11 and Nahum 13

["Fine, Gil" <gil.fine@linux.intel.com>]

On 5/25/2025 11:38, Vitaly Lifshits wrote:
> On some systems with Nahum 11 and Nahum 13 the value of the XTAL clock in
> the software STRAP is incorrect. This causes the PTP timer to run at the
> wrong rate and can lead to synchronization issues.
>
> The STRAP value is configured by the system firmware, and a firmware
> update is not always possible. Since the XTAL clock on these systems
> always runs at 38.4MHz, the driver may ignore the STRAP and just set
> the correct value.
>
> Fixes: cc23f4f0b6b9 ("e1000e: Add support for Meteor Lake")
> Signed-off-by: Vitaly Lifshits <vitaly.lifshits@intel.com>
Reviewed-by: Gil Fine <gil.fine@linux.intel.com>
> ---
>   drivers/net/ethernet/intel/e1000e/netdev.c | 14 +++++++++++---
>   drivers/net/ethernet/intel/e1000e/ptp.c    |  9 ++++++---
>   2 files changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 8ebcb6a7d608..9d2098ed4969 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -3534,9 +3534,6 @@ s32 e1000e_get_base_timinca(struct e1000_adapter *adapter, u32 *timinca)
>   	case e1000_pch_cnp:
>   	case e1000_pch_tgp:
>   	case e1000_pch_adp:
> -	case e1000_pch_mtp:
> -	case e1000_pch_lnp:
> -	case e1000_pch_ptp:
>   	case e1000_pch_nvp:
>   		if (er32(TSYNCRXCTL) & E1000_TSYNCRXCTL_SYSCFI) {
>   			/* Stable 24MHz frequency */
> @@ -3552,6 +3549,17 @@ s32 e1000e_get_base_timinca(struct e1000_adapter *adapter, u32 *timinca)
>   			adapter->cc.shift = shift;
>   		}
>   		break;
> +	case e1000_pch_mtp:
> +	case e1000_pch_lnp:
> +	case e1000_pch_ptp:
> +			/* System firmware can misreport this value, so set it to a
> +			 * stable 38400KHz frequency.
> +			 */
> +			incperiod = INCPERIOD_38400KHZ;
> +			incvalue = INCVALUE_38400KHZ;
> +			shift = INCVALUE_SHIFT_38400KHZ;
> +			adapter->cc.shift = shift;
> +		break;
>   	case e1000_82574:
>   	case e1000_82583:
>   		/* Stable 25MHz frequency */
> diff --git a/drivers/net/ethernet/intel/e1000e/ptp.c b/drivers/net/ethernet/intel/e1000e/ptp.c
> index 89d57dd911dc..992aec8a4538 100644
> --- a/drivers/net/ethernet/intel/e1000e/ptp.c
> +++ b/drivers/net/ethernet/intel/e1000e/ptp.c
> @@ -295,15 +295,18 @@ void e1000e_ptp_init(struct e1000_adapter *adapter)
>   	case e1000_pch_cnp:
>   	case e1000_pch_tgp:
>   	case e1000_pch_adp:
> -	case e1000_pch_mtp:
> -	case e1000_pch_lnp:
> -	case e1000_pch_ptp:
>   	case e1000_pch_nvp:
>   		if (er32(TSYNCRXCTL) & E1000_TSYNCRXCTL_SYSCFI)
>   			adapter->ptp_clock_info.max_adj = MAX_PPB_24MHZ;
>   		else
>   			adapter->ptp_clock_info.max_adj = MAX_PPB_38400KHZ;
>   		break;
> +	case e1000_pch_mtp:
> +	case e1000_pch_lnp:
> +	case e1000_pch_ptp:
> +		adapter->ptp_clock_info.max_adj = MAX_PPB_38400KHZ;
> +		break;
> +
>   	case e1000_82574:
>   	case e1000_82583:
>   		adapter->ptp_clock_info.max_adj = MAX_PPB_25MHZ;