Commit ad7d4eae authored by Shawn Bohrer's avatar Shawn Bohrer Committed by David S. Miller

mlx4_en: Add PTP hardware clock

This adds a PHC to the mlx4_en driver. We use reader/writer spinlocks to
protect the timecounter since every packet received needs to call
timecounter_cycle2time() when timestamping is enabled.  This can become
a performance bottleneck with RSS and multiple receive queues if normal
spinlocks are used.

This driver has been tested with both Documentation/ptp/testptp and the
linuxptp project (http://linuxptp.sourceforge.net/) on a Mellanox
ConnectX-3 card.
Signed-off-by: default avatarShawn Bohrer <sbohrer@rgmadvisors.com>
Acked-By: default avatarHadar Hen Zion <hadarh@mellanox.com>
Acked-by: default avatarRichard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dd9b4559
......@@ -103,19 +103,191 @@ void mlx4_en_fill_hwtstamps(struct mlx4_en_dev *mdev,
struct skb_shared_hwtstamps *hwts,
u64 timestamp)
{
unsigned long flags;
u64 nsec;
read_lock_irqsave(&mdev->clock_lock, flags);
nsec = timecounter_cyc2time(&mdev->clock, timestamp);
read_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) {
write_lock_irqsave(&mdev->clock_lock, flags);
timecounter_read(&mdev->clock);
write_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);
write_lock_irqsave(&mdev->clock_lock, flags);
timecounter_read(&mdev->clock);
mdev->cycles.mult = neg_adj ? mult - diff : mult + diff;
write_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;
write_lock_irqsave(&mdev->clock_lock, flags);
now = timecounter_read(&mdev->clock);
now += delta;
timecounter_init(&mdev->clock, &mdev->cycles, now);
write_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;
write_lock_irqsave(&mdev->clock_lock, flags);
ns = timecounter_read(&mdev->clock);
write_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 */
write_lock_irqsave(&mdev->clock_lock, flags);
timecounter_init(&mdev->clock, &mdev->cycles, ns);
write_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;
rwlock_init(&mdev->clock_lock);
memset(&mdev->cycles, 0, sizeof(mdev->cycles));
mdev->cycles.read = mlx4_en_read_clock;
mdev->cycles.mask = CLOCKSOURCE_MASK(48);
......@@ -127,9 +299,12 @@ 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;
write_lock_irqsave(&mdev->clock_lock, flags);
timecounter_init(&mdev->clock, &mdev->cycles,
ktime_to_ns(ktime_get_real()));
write_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 +312,18 @@ 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");
}
}
......@@ -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;
......
......@@ -199,6 +199,9 @@ 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);
......
......@@ -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>
......@@ -375,10 +376,14 @@ struct mlx4_en_dev {
u32 priv_pdn;
spinlock_t uar_lock;
u8 mac_removed[MLX4_MAX_PORTS + 1];
rwlock_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;
};
......@@ -791,6 +796,7 @@ 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);
......
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