net/mlx5: Refactor real time clock operation checks for PHC

Check if the MTUTC register of the NIC can be modified before attempting to
execute a real-time clock operation. Previous implementation aborted the
real-time clock operation pre-emptively when the MTUTC register used to
control the real-time clock was not modifiable, indicating real-time clock
mode was not enabled on the NIC. The original control flow was confusing
since the noop-if-RTC-disabled branch looked similar to an error handling
guard clause. The purpose of this patch is purely for improving readability
and should lead to no functional change.

Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
index aa29f09e83564270b62c8abfe4e4f81e5e672408..c4f4d1c6346347d00a80da79d7b0daa77daccf93 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
@@ -266,9 +266,6 @@ static int mlx5_ptp_settime_real_time(struct mlx5_core_dev *mdev,
 {
        u32 in[MLX5_ST_SZ_DW(mtutc_reg)] = {};
 
-       if (!mlx5_modify_mtutc_allowed(mdev))
-               return 0;
-
        if (ts->tv_sec < 0 || ts->tv_sec > U32_MAX ||
            ts->tv_nsec < 0 || ts->tv_nsec > NSEC_PER_SEC)
                return -EINVAL;
@@ -286,12 +283,15 @@ static int mlx5_ptp_settime(struct ptp_clock_info *ptp, const struct timespec64
        struct mlx5_timer *timer = &clock->timer;
        struct mlx5_core_dev *mdev;
        unsigned long flags;
-       int err;
 
        mdev = container_of(clock, struct mlx5_core_dev, clock);
-       err = mlx5_ptp_settime_real_time(mdev, ts);
-       if (err)
-               return err;
+
+       if (mlx5_modify_mtutc_allowed(mdev)) {
+               int err = mlx5_ptp_settime_real_time(mdev, ts);
+
+               if (err)
+                       return err;
+       }
 
        write_seqlock_irqsave(&clock->lock, flags);
        timecounter_init(&timer->tc, &timer->cycles, timespec64_to_ns(ts));
@@ -341,9 +341,6 @@ static int mlx5_ptp_adjtime_real_time(struct mlx5_core_dev *mdev, s64 delta)
 {
        u32 in[MLX5_ST_SZ_DW(mtutc_reg)] = {};
 
-       if (!mlx5_modify_mtutc_allowed(mdev))
-               return 0;
-
        /* HW time adjustment range is checked. If out of range, settime instead */
        if (!mlx5_is_mtutc_time_adj_cap(mdev, delta)) {
                struct timespec64 ts;
@@ -367,13 +364,16 @@ static int mlx5_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
        struct mlx5_timer *timer = &clock->timer;
        struct mlx5_core_dev *mdev;
        unsigned long flags;
-       int err;
 
        mdev = container_of(clock, struct mlx5_core_dev, clock);
 
-       err = mlx5_ptp_adjtime_real_time(mdev, delta);
-       if (err)
-               return err;
+       if (mlx5_modify_mtutc_allowed(mdev)) {
+               int err = mlx5_ptp_adjtime_real_time(mdev, delta);
+
+               if (err)
+                       return err;
+       }
+
        write_seqlock_irqsave(&clock->lock, flags);
        timecounter_adjtime(&timer->tc, delta);
        mlx5_update_clock_info_page(mdev);
@@ -391,9 +391,6 @@ static int mlx5_ptp_freq_adj_real_time(struct mlx5_core_dev *mdev, long scaled_p
 {
        u32 in[MLX5_ST_SZ_DW(mtutc_reg)] = {};
 
-       if (!mlx5_modify_mtutc_allowed(mdev))
-               return 0;
-
        MLX5_SET(mtutc_reg, in, operation, MLX5_MTUTC_OPERATION_ADJUST_FREQ_UTC);
 
        if (MLX5_CAP_MCAM_FEATURE(mdev, mtutc_freq_adj_units)) {
@@ -415,13 +412,15 @@ static int mlx5_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
        struct mlx5_core_dev *mdev;
        unsigned long flags;
        u32 mult;
-       int err;
 
        mdev = container_of(clock, struct mlx5_core_dev, clock);
 
-       err = mlx5_ptp_freq_adj_real_time(mdev, scaled_ppm);
-       if (err)
-               return err;
+       if (mlx5_modify_mtutc_allowed(mdev)) {
+               int err = mlx5_ptp_freq_adj_real_time(mdev, scaled_ppm);
+
+               if (err)
+                       return err;
+       }
 
        mult = (u32)adjust_by_scaled_ppm(timer->nominal_c_mult, scaled_ppm);