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Subject[PATCH net-next v3 04/11] net: ethernet: ti: cpts: switch to use new .gettimex64() interface
Date
The CPTS HW latches and saves CPTS counter value in CPTS fifo immediately
after writing to CPSW_CPTS_PUSH.TS_PUSH (bit 0), so the total time that the
driver needs to read the CPTS timestamp is the time required CPSW_CPTS_PUSH
write to actually reach HW.

Hence switch CPTS driver to implement new .gettimex64() callback for more
precise measurement of the offset between a PHC and the system clock which
is measured as time between
write(CPSW_CPTS_PUSH)
read(CPSW_CPTS_PUSH)

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
drivers/net/ethernet/ti/cpts.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index e6a8ccae711c..7e4c1de0d207 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -203,9 +203,13 @@ static u64 cpts_systim_read(const struct cyclecounter *cc)
return READ_ONCE(cpts->cur_timestamp);
}

-static void cpts_update_cur_time(struct cpts *cpts, int match)
+static void cpts_update_cur_time(struct cpts *cpts, int match,
+ struct ptp_system_timestamp *sts)
{
+ ptp_read_system_prets(sts);
cpts_write32(cpts, TS_PUSH, ts_push);
+ cpts_read32(cpts, ts_push);
+ ptp_read_system_postts(sts);

if (cpts_fifo_read(cpts, match) && match != -1)
dev_err(cpts->dev, "cpts: unable to obtain a time stamp\n");
@@ -234,7 +238,7 @@ static int cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)

cpts->mult_new = neg_adj ? mult - diff : mult + diff;

- cpts_update_cur_time(cpts, CPTS_EV_PUSH);
+ cpts_update_cur_time(cpts, CPTS_EV_PUSH, NULL);

spin_unlock_irqrestore(&cpts->lock, flags);

@@ -253,15 +257,17 @@ static int cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
return 0;
}

-static int cpts_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
+static int cpts_ptp_gettimeex(struct ptp_clock_info *ptp,
+ struct timespec64 *ts,
+ struct ptp_system_timestamp *sts)
{
- u64 ns;
- unsigned long flags;
struct cpts *cpts = container_of(ptp, struct cpts, info);
+ unsigned long flags;
+ u64 ns;

spin_lock_irqsave(&cpts->lock, flags);

- cpts_update_cur_time(cpts, CPTS_EV_PUSH);
+ cpts_update_cur_time(cpts, CPTS_EV_PUSH, sts);

ns = timecounter_read(&cpts->tc);
spin_unlock_irqrestore(&cpts->lock, flags);
@@ -302,7 +308,7 @@ static long cpts_overflow_check(struct ptp_clock_info *ptp)

spin_lock_irqsave(&cpts->lock, flags);

- cpts_update_cur_time(cpts, -1);
+ cpts_update_cur_time(cpts, -1, NULL);

ns = timecounter_read(&cpts->tc);

@@ -326,7 +332,7 @@ static const struct ptp_clock_info cpts_info = {
.pps = 0,
.adjfreq = cpts_ptp_adjfreq,
.adjtime = cpts_ptp_adjtime,
- .gettime64 = cpts_ptp_gettime,
+ .gettimex64 = cpts_ptp_gettimeex,
.settime64 = cpts_ptp_settime,
.enable = cpts_ptp_enable,
.do_aux_work = cpts_overflow_check,
--
2.17.1
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