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Message-ID: <20241012114751.2508834-1-maheshb@google.com>
Date: Sat, 12 Oct 2024 04:47:51 -0700
From: Mahesh Bandewar <maheshb@...gle.com>
To: Netdev <netdev@...r.kernel.org>, Tariq Toukan <tariqt@...dia.com>,
Yishai Hadas <yishaih@...dia.com>
Cc: Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
David Miller <davem@...emloft.net>, Paolo Abeni <pabeni@...hat.com>,
Richard Cochran <richardcochran@...il.com>, Mahesh Bandewar <mahesh@...dewar.net>,
Mahesh Bandewar <maheshb@...gle.com>
Subject: [PATCHv2 net-next 1/3] mlx4: introduce the time_cache into the mlx4
PTP implementation
The mlx4_clock_read() function, when invoked by cycle_counter->read(),
previously returned only the raw cycle count. However, for PTP helpers
like gettimex64(), which require both pre- and post-timestamps,
returning just the raw cycles is insufficient; the necessary
timestamps must also be provided.
This patch introduces the time_cache into the implementation. As a
result, mlx4_en_read_clock() is now responsible for reading and
updating the clock_cache. This allows the function
mlx4_en_read_clock_cache() to serve as the cycle reader for
cycle_counter->read(), maintaining the same interface
Signed-off-by: Mahesh Bandewar <maheshb@...gle.com>
---
drivers/net/ethernet/mellanox/mlx4/en_clock.c | 28 +++++++++++++++----
drivers/net/ethernet/mellanox/mlx4/main.c | 1 -
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 +
3 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index cd754cd76bde..cab9221a0b26 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -36,15 +36,22 @@
#include "mlx4_en.h"
-/* mlx4_en_read_clock - read raw cycle counter (to be used by time counter)
+/* mlx4_en_read_clock_cache - read cached raw cycle counter (to be
+ * used by time counter)
*/
-static u64 mlx4_en_read_clock(const struct cyclecounter *tc)
+static u64 mlx4_en_read_clock_cache(const struct cyclecounter *tc)
{
struct mlx4_en_dev *mdev =
container_of(tc, struct mlx4_en_dev, cycles);
- struct mlx4_dev *dev = mdev->dev;
- return mlx4_read_clock(dev) & tc->mask;
+ return READ_ONCE(mdev->clock_cache) & tc->mask;
+}
+
+static void mlx4_en_read_clock(struct mlx4_en_dev *mdev)
+{
+ u64 cycles = mlx4_read_clock(mdev->dev);
+
+ WRITE_ONCE(mdev->clock_cache, cycles);
}
u64 mlx4_en_get_cqe_ts(struct mlx4_cqe *cqe)
@@ -109,6 +116,9 @@ void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
if (timeout) {
write_seqlock_irqsave(&mdev->clock_lock, flags);
+ /* refresh the clock_cache */
+ mlx4_en_read_clock(mdev);
+
timecounter_read(&mdev->clock);
write_sequnlock_irqrestore(&mdev->clock_lock, flags);
mdev->last_overflow_check = jiffies;
@@ -135,6 +145,8 @@ static int mlx4_en_phc_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
mult = (u32)adjust_by_scaled_ppm(mdev->nominal_c_mult, scaled_ppm);
write_seqlock_irqsave(&mdev->clock_lock, flags);
+ /* refresh the clock_cache */
+ mlx4_en_read_clock(mdev);
timecounter_read(&mdev->clock);
mdev->cycles.mult = mult;
write_sequnlock_irqrestore(&mdev->clock_lock, flags);
@@ -179,6 +191,8 @@ static int mlx4_en_phc_gettime(struct ptp_clock_info *ptp,
u64 ns;
write_seqlock_irqsave(&mdev->clock_lock, flags);
+ /* refresh the clock_cache */
+ mlx4_en_read_clock(mdev);
ns = timecounter_read(&mdev->clock);
write_sequnlock_irqrestore(&mdev->clock_lock, flags);
@@ -205,6 +219,8 @@ static int mlx4_en_phc_settime(struct ptp_clock_info *ptp,
/* reset the timecounter */
write_seqlock_irqsave(&mdev->clock_lock, flags);
+ /* refresh the clock_cache */
+ mlx4_en_read_clock(mdev);
timecounter_init(&mdev->clock, &mdev->cycles, ns);
write_sequnlock_irqrestore(&mdev->clock_lock, flags);
@@ -273,7 +289,7 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
seqlock_init(&mdev->clock_lock);
memset(&mdev->cycles, 0, sizeof(mdev->cycles));
- mdev->cycles.read = mlx4_en_read_clock;
+ mdev->cycles.read = mlx4_en_read_clock_cache;
mdev->cycles.mask = CLOCKSOURCE_MASK(48);
mdev->cycles.shift = freq_to_shift(dev->caps.hca_core_clock);
mdev->cycles.mult =
@@ -281,6 +297,8 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
mdev->nominal_c_mult = mdev->cycles.mult;
write_seqlock_irqsave(&mdev->clock_lock, flags);
+ /* initialize the clock_cache */
+ mlx4_en_read_clock(mdev);
timecounter_init(&mdev->clock, &mdev->cycles,
ktime_to_ns(ktime_get_real()));
write_sequnlock_irqrestore(&mdev->clock_lock, flags);
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index febeadfdd5a5..9408313b0f4d 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -1946,7 +1946,6 @@ u64 mlx4_read_clock(struct mlx4_dev *dev)
}
EXPORT_SYMBOL_GPL(mlx4_read_clock);
-
static int map_internal_clock(struct mlx4_dev *dev)
{
struct mlx4_priv *priv = mlx4_priv(dev);
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 28b70dcc652e..077b529eb01a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -435,6 +435,7 @@ struct mlx4_en_dev {
unsigned long last_overflow_check;
struct ptp_clock *ptp_clock;
struct ptp_clock_info ptp_clock_info;
+ u64 clock_cache;
struct notifier_block netdev_nb;
struct notifier_block mlx_nb;
};
--
2.47.0.rc1.288.g06298d1525-goog
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