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net: phy: Add support for 1PPS out and external timestamps
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The perout function is used to generate a 1PPS signal, synchronized
to the PHC.  This is accomplished by a using the hardware oneshot
functionality, which is reset by a timer.

The external timestamp function is set up for a 1PPS input pulse,
and uses a timer to poll for temestamps.

Both functions use the SYNC_OUT/SYNC_IN1 pin, so cannot run
simultaneously.

Co-developed-by: Lasse Johnsen <l@ssejohnsen.me>
Signed-off-by: Lasse Johnsen <l@ssejohnsen.me>
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Jonathan Lemon authored and Jakub Kicinski committed Jun 24, 2022
1 parent 39db6be commit 7bfe91e
Showing 1 changed file with 226 additions and 0 deletions.
226 changes: 226 additions & 0 deletions drivers/net/phy/bcm-phy-ptp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,8 @@
#define SYNC_OUT_1 0x0879
#define SYNC_OUT_2 0x087a

#define SYNC_IN_DIVIDER 0x087b

#define SYNOUT_TS_0 0x087c
#define SYNOUT_TS_1 0x087d
#define SYNOUT_TS_2 0x087e
Expand All @@ -89,6 +91,7 @@
#define NSE_CAPTURE_EN BIT(13)
#define NSE_INIT BIT(12)
#define NSE_CPU_FRAMESYNC BIT(5)
#define NSE_SYNC1_FRAMESYNC BIT(3)
#define NSE_FRAMESYNC_MASK GENMASK(5, 2)
#define NSE_PEROUT_EN BIT(1)
#define NSE_ONESHOT_EN BIT(0)
Expand Down Expand Up @@ -128,11 +131,14 @@ struct bcm_ptp_private {
struct mii_timestamper mii_ts;
struct ptp_clock *ptp_clock;
struct ptp_clock_info ptp_info;
struct ptp_pin_desc pin;
struct mutex mutex;
struct sk_buff_head tx_queue;
int tx_type;
bool hwts_rx;
u16 nse_ctrl;
bool pin_active;
struct delayed_work pin_work;
};

struct bcm_ptp_skb_cb {
Expand Down Expand Up @@ -511,6 +517,215 @@ static long bcm_ptp_do_aux_work(struct ptp_clock_info *info)
return reschedule ? 1 : -1;
}

static int bcm_ptp_cancel_func(struct bcm_ptp_private *priv)
{
if (!priv->pin_active)
return 0;

priv->pin_active = false;

priv->nse_ctrl &= ~(NSE_SYNC_OUT_MASK | NSE_SYNC1_FRAMESYNC |
NSE_CAPTURE_EN);
bcm_phy_write_exp(priv->phydev, NSE_CTRL, priv->nse_ctrl);

cancel_delayed_work_sync(&priv->pin_work);

return 0;
}

static void bcm_ptp_perout_work(struct work_struct *pin_work)
{
struct bcm_ptp_private *priv =
container_of(pin_work, struct bcm_ptp_private, pin_work.work);
struct phy_device *phydev = priv->phydev;
struct timespec64 ts;
u64 ns, next;
u16 ctrl;

mutex_lock(&priv->mutex);

/* no longer running */
if (!priv->pin_active) {
mutex_unlock(&priv->mutex);
return;
}

bcm_ptp_framesync_ts(phydev, NULL, &ts, priv->nse_ctrl);

/* this is 1PPS only */
next = NSEC_PER_SEC - ts.tv_nsec;
ts.tv_sec += next < NSEC_PER_MSEC ? 2 : 1;
ts.tv_nsec = 0;

ns = timespec64_to_ns(&ts);

/* force 0->1 transition for ONESHOT */
ctrl = bcm_ptp_framesync_disable(phydev,
priv->nse_ctrl & ~NSE_ONESHOT_EN);

bcm_phy_write_exp(phydev, SYNOUT_TS_0, ns & 0xfff0);
bcm_phy_write_exp(phydev, SYNOUT_TS_1, ns >> 16);
bcm_phy_write_exp(phydev, SYNOUT_TS_2, ns >> 32);

/* load values on next framesync */
bcm_phy_write_exp(phydev, SHADOW_LOAD, SYNC_OUT_LOAD);

bcm_ptp_framesync(phydev, ctrl | NSE_ONESHOT_EN | NSE_INIT);

priv->nse_ctrl |= NSE_ONESHOT_EN;
bcm_ptp_framesync_restore(phydev, priv->nse_ctrl);

mutex_unlock(&priv->mutex);

next = next + NSEC_PER_MSEC;
schedule_delayed_work(&priv->pin_work, nsecs_to_jiffies(next));
}

static int bcm_ptp_perout_locked(struct bcm_ptp_private *priv,
struct ptp_perout_request *req, int on)
{
struct phy_device *phydev = priv->phydev;
u64 period, pulse;
u16 val;

if (!on)
return bcm_ptp_cancel_func(priv);

/* 1PPS */
if (req->period.sec != 1 || req->period.nsec != 0)
return -EINVAL;

period = BCM_MAX_PERIOD_8NS; /* write nonzero value */

if (req->flags & PTP_PEROUT_PHASE)
return -EOPNOTSUPP;

if (req->flags & PTP_PEROUT_DUTY_CYCLE)
pulse = ktime_to_ns(ktime_set(req->on.sec, req->on.nsec));
else
pulse = (u64)BCM_MAX_PULSE_8NS << 3;

/* convert to 8ns units */
pulse >>= 3;

if (!pulse || pulse > period || pulse > BCM_MAX_PULSE_8NS)
return -EINVAL;

bcm_phy_write_exp(phydev, SYNC_OUT_0, period);

val = ((pulse & 0x3) << 14) | ((period >> 16) & 0x3fff);
bcm_phy_write_exp(phydev, SYNC_OUT_1, val);

val = ((pulse >> 2) & 0x7f) | (pulse << 7);
bcm_phy_write_exp(phydev, SYNC_OUT_2, val);

if (priv->pin_active)
cancel_delayed_work_sync(&priv->pin_work);

priv->pin_active = true;
INIT_DELAYED_WORK(&priv->pin_work, bcm_ptp_perout_work);
schedule_delayed_work(&priv->pin_work, 0);

return 0;
}

static void bcm_ptp_extts_work(struct work_struct *pin_work)
{
struct bcm_ptp_private *priv =
container_of(pin_work, struct bcm_ptp_private, pin_work.work);
struct phy_device *phydev = priv->phydev;
struct ptp_clock_event event;
struct timespec64 ts;
u16 reg;

mutex_lock(&priv->mutex);

/* no longer running */
if (!priv->pin_active) {
mutex_unlock(&priv->mutex);
return;
}

reg = bcm_phy_read_exp(phydev, INTR_STATUS);
if ((reg & INTC_FSYNC) == 0)
goto out;

bcm_ptp_get_framesync_ts(phydev, &ts);

event.index = 0;
event.type = PTP_CLOCK_EXTTS;
event.timestamp = timespec64_to_ns(&ts);
ptp_clock_event(priv->ptp_clock, &event);

out:
mutex_unlock(&priv->mutex);
schedule_delayed_work(&priv->pin_work, HZ / 4);
}

static int bcm_ptp_extts_locked(struct bcm_ptp_private *priv, int on)
{
struct phy_device *phydev = priv->phydev;

if (!on)
return bcm_ptp_cancel_func(priv);

if (priv->pin_active)
cancel_delayed_work_sync(&priv->pin_work);

bcm_ptp_framesync_disable(phydev, priv->nse_ctrl);

priv->nse_ctrl |= NSE_SYNC1_FRAMESYNC | NSE_CAPTURE_EN;

bcm_ptp_framesync_restore(phydev, priv->nse_ctrl);

priv->pin_active = true;
INIT_DELAYED_WORK(&priv->pin_work, bcm_ptp_extts_work);
schedule_delayed_work(&priv->pin_work, 0);

return 0;
}

static int bcm_ptp_enable(struct ptp_clock_info *info,
struct ptp_clock_request *rq, int on)
{
struct bcm_ptp_private *priv = ptp2priv(info);
int err = -EBUSY;

mutex_lock(&priv->mutex);

switch (rq->type) {
case PTP_CLK_REQ_PEROUT:
if (priv->pin.func == PTP_PF_PEROUT)
err = bcm_ptp_perout_locked(priv, &rq->perout, on);
break;
case PTP_CLK_REQ_EXTTS:
if (priv->pin.func == PTP_PF_EXTTS)
err = bcm_ptp_extts_locked(priv, on);
break;
default:
err = -EOPNOTSUPP;
break;
}

mutex_unlock(&priv->mutex);

return err;
}

static int bcm_ptp_verify(struct ptp_clock_info *info, unsigned int pin,
enum ptp_pin_function func, unsigned int chan)
{
switch (func) {
case PTP_PF_NONE:
case PTP_PF_EXTTS:
case PTP_PF_PEROUT:
break;
default:
return -EOPNOTSUPP;
}
return 0;
}

static const struct ptp_clock_info bcm_ptp_clock_info = {
.owner = THIS_MODULE,
.name = KBUILD_MODNAME,
Expand All @@ -519,7 +734,12 @@ static const struct ptp_clock_info bcm_ptp_clock_info = {
.settime64 = bcm_ptp_settime,
.adjtime = bcm_ptp_adjtime,
.adjfine = bcm_ptp_adjfine,
.enable = bcm_ptp_enable,
.verify = bcm_ptp_verify,
.do_aux_work = bcm_ptp_do_aux_work,
.n_pins = 1,
.n_per_out = 1,
.n_ext_ts = 1,
};

static void bcm_ptp_txtstamp(struct mii_timestamper *mii_ts,
Expand Down Expand Up @@ -648,6 +868,7 @@ static int bcm_ptp_ts_info(struct mii_timestamper *mii_ts,
void bcm_ptp_stop(struct bcm_ptp_private *priv)
{
ptp_cancel_worker_sync(priv->ptp_clock);
bcm_ptp_cancel_func(priv);
}
EXPORT_SYMBOL_GPL(bcm_ptp_stop);

Expand All @@ -667,6 +888,8 @@ void bcm_ptp_config_init(struct phy_device *phydev)

/* always allow FREQ_LOAD on framesync */
bcm_phy_write_exp(phydev, SHADOW_CTRL, FREQ_LOAD);

bcm_phy_write_exp(phydev, SYNC_IN_DIVIDER, 1);
}
EXPORT_SYMBOL_GPL(bcm_ptp_config_init);

Expand Down Expand Up @@ -703,6 +926,9 @@ struct bcm_ptp_private *bcm_ptp_probe(struct phy_device *phydev)

priv->ptp_info = bcm_ptp_clock_info;

snprintf(priv->pin.name, sizeof(priv->pin.name), "SYNC_OUT");
priv->ptp_info.pin_config = &priv->pin;

clock = ptp_clock_register(&priv->ptp_info, &phydev->mdio.dev);
if (IS_ERR(clock))
return ERR_CAST(clock);
Expand Down

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