Commit d82303df authored by Jacob Keller's avatar Jacob Keller Committed by Jakub Kicinski
Browse files

mlxsw: update adjfine to use adjust_by_scaled_ppm 



The mlxsw adjfine implementation in the spectrum_ptp.c file converts
scaled_ppm into ppb before updating a cyclecounter multiplier using the
standard "base * ppb / 1billion" calculation.

This can be re-written to use adjust_by_scaled_ppm, directly using the
scaled parts per million and reducing the amount of code required to
express this calculation.

We still calculate the parts per billion for passing into
mlxsw_sp_ptp_phc_adjfreq because this function requires the input to be in
parts per billion.

Signed-off-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Cc: Amit Cohen <amcohen@nvidia.com>
Cc: Petr Machata <petrm@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Tested-by: default avatarIdo Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20221114213701.815132-1-jacob.e.keller@intel.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent bf36267e

drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c

+3 −15
Original line number Diff line number Diff line
@@ -189,29 +189,17 @@ mlxsw_sp1_ptp_phc_settime(struct mlxsw_sp1_ptp_clock *clock, u64 nsec) 
static int mlxsw_sp1_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)

{

	struct mlxsw_sp1_ptp_clock *clock = mlxsw_sp1_ptp_clock(ptp);

	int neg_adj = 0;

	u32 diff;

	u64 adj;

	s32 ppb;



	ppb = scaled_ppm_to_ppb(scaled_ppm);



	if (ppb < 0) {

		neg_adj = 1;

		ppb = -ppb;

	}



	adj = clock->nominal_c_mult;

	adj *= ppb;

	diff = div_u64(adj, NSEC_PER_SEC);



	spin_lock_bh(&clock->lock);

	timecounter_read(&clock->tc);

	clock->cycles.mult = neg_adj ? clock->nominal_c_mult - diff :

				       clock->nominal_c_mult + diff;

	clock->cycles.mult = adjust_by_scaled_ppm(clock->nominal_c_mult,

						  scaled_ppm);

	spin_unlock_bh(&clock->lock);



	return mlxsw_sp_ptp_phc_adjfreq(&clock->common, neg_adj ? -ppb : ppb);

	return mlxsw_sp_ptp_phc_adjfreq(&clock->common, ppb);

}



static int mlxsw_sp1_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)