[PATCH net-next 2/2] net/mlx5: Support cross-timestamping on ARM architectures

From: Tariq Toukan

Date: Mon Mar 16 2026 - 09:44:35 EST


From: Carolina Jubran <cjubran@xxxxxxxxxx>

Extend cross-timestamp support for ARM systems that implement the ARM
architected timer.

Signed-off-by: Carolina Jubran <cjubran@xxxxxxxxxx>
Reviewed-by: Shahar Shitrit <shshitrit@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
---
.../net/ethernet/mellanox/mlx5/core/lib/clock.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
index 3322814819ea..d785f1b4f2e1 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
@@ -38,10 +38,10 @@
#include "lib/eq.h"
#include "en.h"
#include "clock.h"
-#ifdef CONFIG_X86
+#if defined(CONFIG_X86) || defined(CONFIG_ARM_ARCH_TIMER)
#include <linux/timekeeping.h>
#include <linux/cpufeature.h>
-#endif /* CONFIG_X86 */
+#endif /* CONFIG_X86 || CONFIG_ARM_ARCH_TIMER */

#define MLX5_RT_CLOCK_IDENTITY_SIZE MLX5_FLD_SZ_BYTES(mrtcq_reg, rt_clock_identity)

@@ -229,7 +229,7 @@ static int mlx5_set_mtutc(struct mlx5_core_dev *dev, u32 *mtutc, u32 size)
MLX5_REG_MTUTC, 0, 1);
}

-#ifdef CONFIG_X86
+#if defined(CONFIG_X86) || defined(CONFIG_ARM_ARCH_TIMER)
static bool mlx5_is_ptm_source_time_available(struct mlx5_core_dev *dev)
{
u32 out[MLX5_ST_SZ_DW(mtptm_reg)] = {0};
@@ -275,7 +275,8 @@ static int mlx5_mtctr_read(struct mlx5_core_dev *mdev,
host = MLX5_GET64(mtctr_reg, out, first_clock_timestamp);
*sys_counterval = (struct system_counterval_t) {
.cycles = host,
- .cs_id = CSID_X86_ART,
+ .cs_id = IS_ENABLED(CONFIG_X86) ? CSID_X86_ART :
+ CSID_ARM_ARCH_COUNTER,
.use_nsecs = true,
};
*device = MLX5_GET64(mtctr_reg, out, second_clock_timestamp);
@@ -373,7 +374,7 @@ static int mlx5_ptp_getcrosscycles(struct ptp_clock_info *ptp,
mlx5_clock_unlock(clock);
return err;
}
-#endif /* CONFIG_X86 */
+#endif /* CONFIG_X86 || CONFIG_ARM_ARCH_TIMER */

static u64 mlx5_read_time(struct mlx5_core_dev *dev,
struct ptp_system_timestamp *sts,
@@ -1307,7 +1308,8 @@ static void mlx5_init_crosststamp(struct mlx5_core_dev *mdev,
#if defined(CONFIG_X86)
if (!boot_cpu_has(X86_FEATURE_ART))
return;
-
+#endif /* CONFIG_X86 */
+#if defined(CONFIG_X86) || defined(CONFIG_ARM_ARCH_TIMER)
if (!MLX5_CAP_MCAM_REG3(mdev, mtptm) ||
!MLX5_CAP_MCAM_REG3(mdev, mtctr))
return;
@@ -1316,7 +1318,7 @@ static void mlx5_init_crosststamp(struct mlx5_core_dev *mdev,
if (expose_cycles)
clock->ptp_info.getcrosscycles = mlx5_ptp_getcrosscycles;

-#endif /* CONFIG_X86 */
+#endif /* CONFIG_X86 || CONFIG_ARM_ARCH_TIMER */
}

static void mlx5_init_timer_clock(struct mlx5_core_dev *mdev)
--
2.44.0