octeontx2-pf: Use PTP HW timestamp counter atomic update feature

Some of the newer silicon versions in CN10K series supports a feature
where in the current PTP timestamp in HW can be updated atomically
without losing any cpu cycles unlike read/modify/write register.
This patch uses this feature so that PTP accuracy can be improved
while adjusting the master offset in HW. There is no need for SW
timecounter when using this feature. So removed references to SW
timecounter wherever appropriate.

Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Signed-off-by: Naveen Mamindlapalli <naveenm@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 145 insertions, 33 deletions

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
index 5fd05d94de7c..4c6032ee7800 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
@@ -326,6 +326,7 @@ struct otx2_ptp {
 	struct ptp_pin_desc extts_config;
 	u64 (*convert_rx_ptp_tstmp)(u64 timestamp);
 	u64 (*convert_tx_ptp_tstmp)(u64 timestamp);
+	u64 (*ptp_tstamp2nsec)(const struct timecounter *time_counter, u64 timestamp);
 	struct delayed_work synctstamp_work;
 	u64 tstamp;
 	u32 base_ns;
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
index 896b2f9bac34..3a72b0793d4a 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
@@ -10,6 +10,65 @@
 #include "otx2_common.h"
 #include "otx2_ptp.h"
 
+static bool is_tstmp_atomic_update_supported(struct otx2_ptp *ptp)
+{
+	struct ptp_get_cap_rsp *rsp;
+	struct msg_req *req;
+	int err;
+
+	if (!ptp->nic)
+		return false;
+
+	mutex_lock(&ptp->nic->mbox.lock);
+	req = otx2_mbox_alloc_msg_ptp_get_cap(&ptp->nic->mbox);
+	if (!req) {
+		mutex_unlock(&ptp->nic->mbox.lock);
+		return false;
+	}
+
+	err = otx2_sync_mbox_msg(&ptp->nic->mbox);
+	if (err) {
+		mutex_unlock(&ptp->nic->mbox.lock);
+		return false;
+	}
+	rsp = (struct ptp_get_cap_rsp *)otx2_mbox_get_rsp(&ptp->nic->mbox.mbox, 0,
+							  &req->hdr);
+	mutex_unlock(&ptp->nic->mbox.lock);
+
+	if (IS_ERR(rsp))
+		return false;
+
+	if (rsp->cap & PTP_CAP_HW_ATOMIC_UPDATE)
+		return true;
+
+	return false;
+}
+
+static int otx2_ptp_hw_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
+{
+	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
+					    ptp_info);
+	struct otx2_nic *pfvf = ptp->nic;
+	struct ptp_req *req;
+	int rc;
+
+	if (!ptp->nic)
+		return -ENODEV;
+
+	mutex_lock(&pfvf->mbox.lock);
+	req = otx2_mbox_alloc_msg_ptp_op(&ptp->nic->mbox);
+	if (!req) {
+		mutex_unlock(&pfvf->mbox.lock);
+		return -ENOMEM;
+	}
+	req->op = PTP_OP_ADJTIME;
+	req->delta = delta;
+	rc = otx2_sync_mbox_msg(&ptp->nic->mbox);
+	mutex_unlock(&pfvf->mbox.lock);
+
+	return rc;
+}
+
 static u64 otx2_ptp_get_clock(struct otx2_ptp *ptp)
 {
 	struct ptp_req *req;
@@ -37,6 +96,49 @@ static u64 otx2_ptp_get_clock(struct otx2_ptp *ptp)
 	return rsp->clk;
 }
 
+static int otx2_ptp_hw_gettime(struct ptp_clock_info *ptp_info,
+			       struct timespec64 *ts)
+{
+	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
+					    ptp_info);
+	u64 tstamp;
+
+	tstamp = otx2_ptp_get_clock(ptp);
+
+	*ts = ns_to_timespec64(tstamp);
+	return 0;
+}
+
+static int otx2_ptp_hw_settime(struct ptp_clock_info *ptp_info,
+			       const struct timespec64 *ts)
+{
+	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
+					    ptp_info);
+	struct otx2_nic *pfvf = ptp->nic;
+	struct ptp_req *req;
+	u64 nsec;
+	int rc;
+
+	if (!ptp->nic)
+		return -ENODEV;
+
+	nsec = timespec64_to_ns(ts);
+
+	mutex_lock(&pfvf->mbox.lock);
+	req = otx2_mbox_alloc_msg_ptp_op(&ptp->nic->mbox);
+	if (!req) {
+		mutex_unlock(&pfvf->mbox.lock);
+		return -ENOMEM;
+	}
+
+	req->op = PTP_OP_SET_CLOCK;
+	req->clk = nsec;
+	rc = otx2_sync_mbox_msg(&ptp->nic->mbox);
+	mutex_unlock(&pfvf->mbox.lock);
+
+	return rc;
+}
+
 static int otx2_ptp_adjfine(struct ptp_clock_info *ptp_info, long scaled_ppm)
 {
 	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
@@ -124,16 +226,7 @@ static u64 ptp_tstmp_read(struct otx2_ptp *ptp)
 	return rsp->clk;
 }
 
-static void otx2_get_ptpclock(struct otx2_ptp *ptp, u64 *tstamp)
-{
-	struct otx2_nic *pfvf = ptp->nic;
-
-	mutex_lock(&pfvf->mbox.lock);
-	*tstamp = timecounter_read(&ptp->time_counter);
-	mutex_unlock(&pfvf->mbox.lock);
-}
-
-static int otx2_ptp_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
+static int otx2_ptp_tc_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
 {
 	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
 					    ptp_info);
@@ -146,32 +239,33 @@ static int otx2_ptp_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
 	return 0;
 }
 
-static int otx2_ptp_gettime(struct ptp_clock_info *ptp_info,
-			    struct timespec64 *ts)
+static int otx2_ptp_tc_gettime(struct ptp_clock_info *ptp_info,
+			       struct timespec64 *ts)
 {
 	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
 					    ptp_info);
 	u64 tstamp;
 
-	otx2_get_ptpclock(ptp, &tstamp);
+	mutex_lock(&ptp->nic->mbox.lock);
+	tstamp = timecounter_read(&ptp->time_counter);
+	mutex_unlock(&ptp->nic->mbox.lock);
 	*ts = ns_to_timespec64(tstamp);
 
 	return 0;
 }
 
-static int otx2_ptp_settime(struct ptp_clock_info *ptp_info,
-			    const struct timespec64 *ts)
+static int otx2_ptp_tc_settime(struct ptp_clock_info *ptp_info,
+			       const struct timespec64 *ts)
 {
 	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
 					    ptp_info);
-	struct otx2_nic *pfvf = ptp->nic;
 	u64 nsec;
 
 	nsec = timespec64_to_ns(ts);
 
-	mutex_lock(&pfvf->mbox.lock);
+	mutex_lock(&ptp->nic->mbox.lock);
 	timecounter_init(&ptp->time_counter, &ptp->cycle_counter, nsec);
-	mutex_unlock(&pfvf->mbox.lock);
+	mutex_unlock(&ptp->nic->mbox.lock);
 
 	return 0;
 }
@@ -190,6 +284,12 @@ static int otx2_ptp_verify_pin(struct ptp_clock_info *ptp, unsigned int pin,
 	return 0;
 }
 
+static u64 otx2_ptp_hw_tstamp2time(const struct timecounter *time_counter, u64 tstamp)
+{
+	/* On HW which supports atomic updates, timecounter is not initialized */
+	return tstamp;
+}
+
 static void otx2_ptp_extts_check(struct work_struct *work)
 {
 	struct otx2_ptp *ptp = container_of(work, struct otx2_ptp,
@@ -204,7 +304,7 @@ static void otx2_ptp_extts_check(struct work_struct *work)
 	if (tstmp != ptp->last_extts) {
 		event.type = PTP_CLOCK_EXTTS;
 		event.index = 0;
-		event.timestamp = timecounter_cyc2time(&ptp->time_counter, tstmp);
+		event.timestamp = ptp->ptp_tstamp2nsec(&ptp->time_counter, tstmp);
 		ptp_clock_event(ptp->ptp_clock, &event);
 		new_thresh = tstmp % 500000000;
 		if (ptp->thresh != new_thresh) {
@@ -229,7 +329,7 @@ static void otx2_sync_tstamp(struct work_struct *work)
 	tstamp = otx2_ptp_get_clock(ptp);
 	mutex_unlock(&pfvf->mbox.lock);
 
-	ptp->tstamp = timecounter_cyc2time(&pfvf->ptp->time_counter, tstamp);
+	ptp->tstamp = ptp->ptp_tstamp2nsec(&ptp->time_counter, tstamp);
 	ptp->base_ns = tstamp % NSEC_PER_SEC;
 
 	schedule_delayed_work(&ptp->synctstamp_work, msecs_to_jiffies(250));
@@ -302,15 +402,6 @@ int otx2_ptp_init(struct otx2_nic *pfvf)
 
 	ptp_ptr->nic = pfvf;
 
-	cc = &ptp_ptr->cycle_counter;
-	cc->read = ptp_cc_read;
-	cc->mask = CYCLECOUNTER_MASK(64);
-	cc->mult = 1;
-	cc->shift = 0;
-
-	timecounter_init(&ptp_ptr->time_counter, &ptp_ptr->cycle_counter,
-			 ktime_to_ns(ktime_get_real()));
-
 	snprintf(ptp_ptr->extts_config.name, sizeof(ptp_ptr->extts_config.name), "TSTAMP");
 	ptp_ptr->extts_config.index = 0;
 	ptp_ptr->extts_config.func = PTP_PF_NONE;
@@ -324,13 +415,33 @@ int otx2_ptp_init(struct otx2_nic *pfvf)
 		.pps            = 0,
 		.pin_config     = &ptp_ptr->extts_config,
 		.adjfine        = otx2_ptp_adjfine,
-		.adjtime        = otx2_ptp_adjtime,
-		.gettime64      = otx2_ptp_gettime,
-		.settime64      = otx2_ptp_settime,
 		.enable         = otx2_ptp_enable,
 		.verify         = otx2_ptp_verify_pin,
 	};
 
+	/* Check whether hardware supports atomic updates to timestamp */
+	if (is_tstmp_atomic_update_supported(ptp_ptr)) {
+		ptp_ptr->ptp_info.adjtime = otx2_ptp_hw_adjtime;
+		ptp_ptr->ptp_info.gettime64 = otx2_ptp_hw_gettime;
+		ptp_ptr->ptp_info.settime64 = otx2_ptp_hw_settime;
+
+		ptp_ptr->ptp_tstamp2nsec = otx2_ptp_hw_tstamp2time;
+	} else {
+		ptp_ptr->ptp_info.adjtime = otx2_ptp_tc_adjtime;
+		ptp_ptr->ptp_info.gettime64 = otx2_ptp_tc_gettime;
+		ptp_ptr->ptp_info.settime64 = otx2_ptp_tc_settime;
+
+		cc = &ptp_ptr->cycle_counter;
+		cc->read = ptp_cc_read;
+		cc->mask = CYCLECOUNTER_MASK(64);
+		cc->mult = 1;
+		cc->shift = 0;
+		ptp_ptr->ptp_tstamp2nsec = timecounter_cyc2time;
+
+		timecounter_init(&ptp_ptr->time_counter, &ptp_ptr->cycle_counter,
+				 ktime_to_ns(ktime_get_real()));
+	}
+
 	INIT_DELAYED_WORK(&ptp_ptr->extts_work, otx2_ptp_extts_check);
 
 	ptp_ptr->ptp_clock = ptp_clock_register(&ptp_ptr->ptp_info, pfvf->dev);
@@ -387,7 +498,7 @@ int otx2_ptp_tstamp2time(struct otx2_nic *pfvf, u64 tstamp, u64 *tsns)
 	if (!pfvf->ptp)
 		return -ENODEV;
 
-	*tsns = timecounter_cyc2time(&pfvf->ptp->time_counter, tstamp);
+	*tsns = pfvf->ptp->ptp_tstamp2nsec(&pfvf->ptp->time_counter, tstamp);
 
 	return 0;
 }