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Date: Tue, 17 Dec 2013 15:46:15 -0600
From: Shawn Bohrer <shawn.bohrer@...il.com>
To: Or Gerlitz <or.gerlitz@...il.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Or Gerlitz <ogerlitz@...lanox.com>,
Amir Vadai <amirv@...lanox.com>,
Richard Cochran <richardcochran@...il.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
tomk@...advisors.com, Hadar Hen Zion <hadarh@...lanox.com>,
Shawn Bohrer <sbohrer@...advisors.com>
Subject: Re: [PATCH net-next 1/2] mlx4_en: Add PTP hardware clock
On Tue, Dec 17, 2013 at 11:04:48PM +0200, Or Gerlitz wrote:
> On Tue, Dec 17, 2013 at 10:32 PM, Shawn Bohrer <shawn.bohrer@...il.com> wrote:
> > From: Shawn Bohrer <sbohrer@...advisors.com>
> >
> > This adds a PHC to the mlx4_en driver. The code is largely based off of
> > the e1000e driver (drivers/net/ethernet/intel/e1000e/ptp.c) which seemed
> > very similar.
> >
> > This driver has been tested with both Documentation/ptp/testptp and the
> > linuxptp project (http://linuxptp.sourceforge.net/) and appears to work
> > on a Mellanox ConnectX-3 card.
>
> so this is V3 -- and what are the V2 --> V3 changes?
Sorry, here is the evolution of this patch:
v2:
* Implemented mlx4_en_phc_adjfreq() in software.
* Protected timecounter with a spinlock
* Set the phc_index in mlx4_en_get_ts_info()
* Use a hard-coded ptp_clock_info.name
v3: is code identical to v2. I simply finished testing it with
linuxptp, cleaned up the commit description a little and sent to davem.
> >
> > Signed-off-by: Shawn Bohrer <sbohrer@...advisors.com>
> > ---
> > drivers/net/ethernet/mellanox/mlx4/en_clock.c | 192 ++++++++++++++++++++++-
> > drivers/net/ethernet/mellanox/mlx4/en_ethtool.c | 3 +
> > drivers/net/ethernet/mellanox/mlx4/en_main.c | 3 +
> > drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 6 +
> > 4 files changed, 196 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
> > index fd64410..9b0d515 100644
> > --- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
> > +++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
> > @@ -103,17 +103,187 @@ void mlx4_en_fill_hwtstamps(struct mlx4_en_dev *mdev,
> > struct skb_shared_hwtstamps *hwts,
> > u64 timestamp)
> > {
> > + unsigned long flags;
> > u64 nsec;
> >
> > + spin_lock_irqsave(&mdev->clock_lock, flags);
> > nsec = timecounter_cyc2time(&mdev->clock, timestamp);
> > + spin_unlock_irqrestore(&mdev->clock_lock, flags);
> >
> > memset(hwts, 0, sizeof(struct skb_shared_hwtstamps));
> > hwts->hwtstamp = ns_to_ktime(nsec);
> > }
> >
> > +/**
> > + * mlx4_en_remove_timestamp - disable PTP device
> > + * @mdev: board private structure
> > + *
> > + * Stop the PTP support.
> > + **/
> > +void mlx4_en_remove_timestamp(struct mlx4_en_dev *mdev)
> > +{
> > + if (mdev->ptp_clock) {
> > + ptp_clock_unregister(mdev->ptp_clock);
> > + mdev->ptp_clock = NULL;
> > + mlx4_info(mdev, "removed PHC\n");
> > + }
> > +}
> > +
> > +void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
> > +{
> > + bool timeout = time_is_before_jiffies(mdev->last_overflow_check +
> > + mdev->overflow_period);
> > + unsigned long flags;
> > +
> > + if (timeout) {
> > + spin_lock_irqsave(&mdev->clock_lock, flags);
> > + timecounter_read(&mdev->clock);
> > + spin_unlock_irqrestore(&mdev->clock_lock, flags);
> > + mdev->last_overflow_check = jiffies;
> > + }
> > +}
> > +
> > +/**
> > + * mlx4_en_phc_adjfreq - adjust the frequency of the hardware clock
> > + * @ptp: ptp clock structure
> > + * @delta: Desired frequency change in parts per billion
> > + *
> > + * Adjust the frequency of the PHC cycle counter by the indicated delta from
> > + * the base frequency.
> > + **/
> > +static int mlx4_en_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta)
> > +{
> > + u64 adj;
> > + u32 diff, mult;
> > + int neg_adj = 0;
> > + unsigned long flags;
> > + struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
> > + ptp_clock_info);
> > +
> > + if (delta < 0) {
> > + neg_adj = 1;
> > + delta = -delta;
> > + }
> > + mult = mdev->nominal_c_mult;
> > + adj = mult;
> > + adj *= delta;
> > + diff = div_u64(adj, 1000000000ULL);
> > +
> > + spin_lock_irqsave(&mdev->clock_lock, flags);
> > + timecounter_read(&mdev->clock);
> > + mdev->cycles.mult = neg_adj ? mult - diff : mult + diff;
> > + spin_unlock_irqrestore(&mdev->clock_lock, flags);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * mlx4_en_phc_adjtime - Shift the time of the hardware clock
> > + * @ptp: ptp clock structure
> > + * @delta: Desired change in nanoseconds
> > + *
> > + * Adjust the timer by resetting the timecounter structure.
> > + **/
> > +static int mlx4_en_phc_adjtime(struct ptp_clock_info *ptp, s64 delta)
> > +{
> > + struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
> > + ptp_clock_info);
> > + unsigned long flags;
> > + s64 now;
> > +
> > + spin_lock_irqsave(&mdev->clock_lock, flags);
> > + now = timecounter_read(&mdev->clock);
> > + now += delta;
> > + timecounter_init(&mdev->clock, &mdev->cycles, now);
> > + spin_unlock_irqrestore(&mdev->clock_lock, flags);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * mlx4_en_phc_gettime - Reads the current time from the hardware clock
> > + * @ptp: ptp clock structure
> > + * @ts: timespec structure to hold the current time value
> > + *
> > + * Read the timecounter and return the correct value in ns after converting
> > + * it into a struct timespec.
> > + **/
> > +static int mlx4_en_phc_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
> > +{
> > + struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
> > + ptp_clock_info);
> > + unsigned long flags;
> > + u32 remainder;
> > + u64 ns;
> > +
> > + spin_lock_irqsave(&mdev->clock_lock, flags);
> > + ns = timecounter_read(&mdev->clock);
> > + spin_unlock_irqrestore(&mdev->clock_lock, flags);
> > +
> > + ts->tv_sec = div_u64_rem(ns, NSEC_PER_SEC, &remainder);
> > + ts->tv_nsec = remainder;
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * mlx4_en_phc_settime - Set the current time on the hardware clock
> > + * @ptp: ptp clock structure
> > + * @ts: timespec containing the new time for the cycle counter
> > + *
> > + * Reset the timecounter to use a new base value instead of the kernel
> > + * wall timer value.
> > + **/
> > +static int mlx4_en_phc_settime(struct ptp_clock_info *ptp,
> > + const struct timespec *ts)
> > +{
> > + struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
> > + ptp_clock_info);
> > + u64 ns = timespec_to_ns(ts);
> > + unsigned long flags;
> > +
> > + /* reset the timecounter */
> > + spin_lock_irqsave(&mdev->clock_lock, flags);
> > + timecounter_init(&mdev->clock, &mdev->cycles, ns);
> > + spin_unlock_irqrestore(&mdev->clock_lock, flags);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * mlx4_en_phc_enable - enable or disable an ancillary feature
> > + * @ptp: ptp clock structure
> > + * @request: Desired resource to enable or disable
> > + * @on: Caller passes one to enable or zero to disable
> > + *
> > + * Enable (or disable) ancillary features of the PHC subsystem.
> > + * Currently, no ancillary features are supported.
> > + **/
> > +static int mlx4_en_phc_enable(struct ptp_clock_info __always_unused *ptp,
> > + struct ptp_clock_request __always_unused *request,
> > + int __always_unused on)
> > +{
> > + return -EOPNOTSUPP;
> > +}
> > +
> > +static const struct ptp_clock_info mlx4_en_ptp_clock_info = {
> > + .owner = THIS_MODULE,
> > + .max_adj = 100000000,
> > + .n_alarm = 0,
> > + .n_ext_ts = 0,
> > + .n_per_out = 0,
> > + .pps = 0,
> > + .adjfreq = mlx4_en_phc_adjfreq,
> > + .adjtime = mlx4_en_phc_adjtime,
> > + .gettime = mlx4_en_phc_gettime,
> > + .settime = mlx4_en_phc_settime,
> > + .enable = mlx4_en_phc_enable,
> > +};
> > +
> > void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
> > {
> > struct mlx4_dev *dev = mdev->dev;
> > + unsigned long flags;
> > u64 ns;
> >
> > memset(&mdev->cycles, 0, sizeof(mdev->cycles));
> > @@ -127,9 +297,12 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
> > mdev->cycles.shift = 14;
> > mdev->cycles.mult =
> > clocksource_khz2mult(1000 * dev->caps.hca_core_clock, mdev->cycles.shift);
> > + mdev->nominal_c_mult = mdev->cycles.mult;
> >
> > + spin_lock_irqsave(&mdev->clock_lock, flags);
> > timecounter_init(&mdev->clock, &mdev->cycles,
> > ktime_to_ns(ktime_get_real()));
> > + spin_unlock_irqrestore(&mdev->clock_lock, flags);
> >
> > /* Calculate period in seconds to call the overflow watchdog - to make
> > * sure counter is checked at least once every wrap around.
> > @@ -137,15 +310,18 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
> > ns = cyclecounter_cyc2ns(&mdev->cycles, mdev->cycles.mask);
> > do_div(ns, NSEC_PER_SEC / 2 / HZ);
> > mdev->overflow_period = ns;
> > -}
> >
> > -void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
> > -{
> > - bool timeout = time_is_before_jiffies(mdev->last_overflow_check +
> > - mdev->overflow_period);
> > + /* Configure the PHC */
> > + mdev->ptp_clock_info = mlx4_en_ptp_clock_info;
> > + snprintf(mdev->ptp_clock_info.name, 16, "mlx4 ptp");
> >
> > - if (timeout) {
> > - timecounter_read(&mdev->clock);
> > - mdev->last_overflow_check = jiffies;
> > + mdev->ptp_clock = ptp_clock_register(&mdev->ptp_clock_info,
> > + &mdev->pdev->dev);
> > + if (IS_ERR(mdev->ptp_clock)) {
> > + mdev->ptp_clock = NULL;
> > + mlx4_err(mdev, "ptp_clock_register failed\n");
> > + } else {
> > + mlx4_info(mdev, "registered PHC clock\n");
> > }
> > +
> > }
> > diff --git a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
> > index 0596f9f..3e8d336 100644
> > --- a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
> > +++ b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
> > @@ -1193,6 +1193,9 @@ static int mlx4_en_get_ts_info(struct net_device *dev,
> > info->rx_filters =
> > (1 << HWTSTAMP_FILTER_NONE) |
> > (1 << HWTSTAMP_FILTER_ALL);
> > +
> > + if (mdev->ptp_clock)
> > + info->phc_index = ptp_clock_index(mdev->ptp_clock);
> > }
> >
> > return ret;
> > diff --git a/drivers/net/ethernet/mellanox/mlx4/en_main.c b/drivers/net/ethernet/mellanox/mlx4/en_main.c
> > index 0d087b0..6268057 100644
> > --- a/drivers/net/ethernet/mellanox/mlx4/en_main.c
> > +++ b/drivers/net/ethernet/mellanox/mlx4/en_main.c
> > @@ -196,6 +196,9 @@ static void mlx4_en_remove(struct mlx4_dev *dev, void *endev_ptr)
> > if (mdev->pndev[i])
> > mlx4_en_destroy_netdev(mdev->pndev[i]);
> >
> > + if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_TS)
> > + mlx4_en_remove_timestamp(mdev);
> > +
> > flush_workqueue(mdev->workqueue);
> > destroy_workqueue(mdev->workqueue);
> > (void) mlx4_mr_free(dev, &mdev->mr);
> > diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> > index f3758de..2b4083f 100644
> > --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> > +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> > @@ -45,6 +45,7 @@
> > #include <linux/dcbnl.h>
> > #endif
> > #include <linux/cpu_rmap.h>
> > +#include <linux/ptp_clock_kernel.h>
> >
> > #include <linux/mlx4/device.h>
> > #include <linux/mlx4/qp.h>
> > @@ -373,10 +374,14 @@ struct mlx4_en_dev {
> > u32 priv_pdn;
> > spinlock_t uar_lock;
> > u8 mac_removed[MLX4_MAX_PORTS + 1];
> > + spinlock_t clock_lock;
> > + u32 nominal_c_mult;
> > struct cyclecounter cycles;
> > struct timecounter clock;
> > unsigned long last_overflow_check;
> > unsigned long overflow_period;
> > + struct ptp_clock *ptp_clock;
> > + struct ptp_clock_info ptp_clock_info;
> > };
> >
> >
> > @@ -786,6 +791,7 @@ void mlx4_en_fill_hwtstamps(struct mlx4_en_dev *mdev,
> > struct skb_shared_hwtstamps *hwts,
> > u64 timestamp);
> > void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev);
> > +void mlx4_en_remove_timestamp(struct mlx4_en_dev *mdev);
> > int mlx4_en_timestamp_config(struct net_device *dev,
> > int tx_type,
> > int rx_filter);
> > --
> > 1.7.7.6
> >
> > --
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