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[PATCH v2 13/13] net: ethernet: ti: cpts: fix overflow check period

From Grygorii Strashko <grygorii.strashko@ti.com>
Newsgroups linux.kernel
Subject [PATCH v2 13/13] net: ethernet: ti: cpts: fix overflow check period
Date 2016-11-29 00:10 +0100
Message-ID <sIDdE-75-39@gated-at.bofh.it> (permalink)
References <sIDdD-75-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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The CPTS drivers uses 8sec period for overflow checking with
assumption that CPTS retclk will not exceed 500MHz. But that's not
true on some TI platforms (Kesytone 2). As result, it is possible that
CPTS counter will overflow more than once between two readings.

Hence, fix it by selecting overflow check period dynamically as
max_sec_before_overflow/2, where
 max_sec_before_overflow = max_counter_val / rftclk_freq.

Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
 drivers/net/ethernet/ti/cpts.c | 10 +++++++---
 drivers/net/ethernet/ti/cpts.h |  4 +---
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index 4761d8c..c96a94a 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -245,7 +245,7 @@ static void cpts_overflow_check(struct work_struct *work)
 
 	cpts_ptp_gettime(&cpts->info, &ts);
 	pr_debug("cpts overflow check at %lld.%09lu\n", ts.tv_sec, ts.tv_nsec);
-	schedule_delayed_work(&cpts->overflow_work, CPTS_OVERFLOW_PERIOD);
+	schedule_delayed_work(&cpts->overflow_work, cpts->ov_check_period);
 }
 
 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
@@ -379,8 +379,7 @@ int cpts_register(struct cpts *cpts)
 	}
 	cpts->phc_index = ptp_clock_index(cpts->clock);
 
-	schedule_delayed_work(&cpts->overflow_work, CPTS_OVERFLOW_PERIOD);
-
+	schedule_delayed_work(&cpts->overflow_work, cpts->ov_check_period);
 	return 0;
 
 err_ptp:
@@ -421,6 +420,11 @@ static void cpts_calc_mult_shift(struct cpts *cpts)
 	if (maxsec > 600 && cpts->cc.mask > UINT_MAX)
 		maxsec = 600;
 
+	/* Calc overflow check period (maxsec / 2) */
+	cpts->ov_check_period = (HZ * maxsec) / 2;
+	dev_info(cpts->dev, "cpts: overflow check period %lu (jiffies)\n",
+		 cpts->ov_check_period);
+
 	if (cpts->cc_mult || cpts->cc.shift)
 		return;
 
diff --git a/drivers/net/ethernet/ti/cpts.h b/drivers/net/ethernet/ti/cpts.h
index 5da23af..c96eca2 100644
--- a/drivers/net/ethernet/ti/cpts.h
+++ b/drivers/net/ethernet/ti/cpts.h
@@ -97,9 +97,6 @@ enum {
 	CPTS_EV_TX,   /* Ethernet Transmit Event */
 };
 
-/* This covers any input clock up to about 500 MHz. */
-#define CPTS_OVERFLOW_PERIOD (HZ * 8)
-
 #define CPTS_FIFO_DEPTH 16
 #define CPTS_MAX_EVENTS 32
 
@@ -127,6 +124,7 @@ struct cpts {
 	struct list_head events;
 	struct list_head pool;
 	struct cpts_event pool_data[CPTS_MAX_EVENTS];
+	unsigned long ov_check_period;
 };
 
 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb);
-- 
2.10.1

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[PATCH v2 00/13] net: ethernet: ti: cpts: update and fixes Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
  [PATCH  v2 12/13] net: ethernet: ti: cpts: calc mult and shift from refclk freq Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH  v2 12/13] net: ethernet: ti: cpts: calc mult and shift  from refclk freq Richard Cochran <richardcochran@gmail.com> - 2016-11-29 11:40 +0100
      Re: [PATCH v2 12/13] net: ethernet: ti: cpts: calc mult and shift  from refclk freq Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 17:30 +0100
  [PATCH  v2 03/13] net: ethernet: ti: cpsw: minimize direct access to struct cpts Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
  [PATCH v2 10/13] net: ethernet: ti: cpts: drop excessive writes to CTRL and INT_EN regs Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH v2 10/13] net: ethernet: ti: cpts: drop excessive writes  to CTRL and INT_EN regs Richard Cochran <richardcochran@gmail.com> - 2016-11-29 11:20 +0100
  [PATCH  v2 06/13] net: ethernet: ti: cpts: disable cpts when unregistered Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH  v2 06/13] net: ethernet: ti: cpts: disable cpts when  unregistered Richard Cochran <richardcochran@gmail.com> - 2016-11-29 11:00 +0100
  [PATCH  v2 07/13] net: ethernet: ti: cpts: rework initialization/deinitialization Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH  v2 07/13] net: ethernet: ti: cpts: rework  initialization/deinitialization Richard Cochran <richardcochran@gmail.com> - 2016-11-29 11:10 +0100
      Re: [PATCH v2 07/13] net: ethernet: ti: cpts: rework  initialization/deinitialization Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 17:00 +0100
        Re: [PATCH v2 07/13] net: ethernet: ti: cpts: rework  initialization/deinitialization Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-30 19:40 +0100
  [PATCH  v2 02/13] net: ethernet: ti: allow cpts to be built separately Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH  v2 02/13] net: ethernet: ti: allow cpts to be built  separately Richard Cochran <richardcochran@gmail.com> - 2016-11-29 10:40 +0100
  [PATCH  v2 01/13] net: ethernet: ti: cpts: switch to readl/writel_relaxed() Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH  v2 01/13] net: ethernet: ti: cpts: switch to  readl/writel_relaxed() Richard Cochran <richardcochran@gmail.com> - 2016-11-29 10:40 +0100
  [PATCH  v2 13/13] net: ethernet: ti: cpts: fix overflow check period Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH  v2 13/13] net: ethernet: ti: cpts: fix overflow check  period Richard Cochran <richardcochran@gmail.com> - 2016-11-30 10:20 +0100
  [PATCH  v2 11/13] clocksource: export the clocks_calc_mult_shift to use by timestamp code Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:10 +0100
    Re: [PATCH v2 11/13] clocksource: export the clocks_calc_mult_shift  to use by timestamp code Thomas Gleixner <tglx@linutronix.de> - 2016-11-29 10:20 +0100
  [PATCH  v2 09/13] net: ethernet: ti: cpts: clean up event list if event pool is empty Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:20 +0100
    Re: [PATCH  v2 09/13] net: ethernet: ti: cpts: clean up event list  if event pool is empty Richard Cochran <richardcochran@gmail.com> - 2016-11-29 11:20 +0100
  [PATCH  v2 04/13] net: ethernet: ti: cpts: fix unbalanced clk api usage in cpts_register/unregister Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:20 +0100
    Re: [PATCH  v2 04/13] net: ethernet: ti: cpts: fix unbalanced clk  api usage in cpts_register/unregister Richard Cochran <richardcochran@gmail.com> - 2016-11-29 10:50 +0100
  [PATCH  v2 08/13] net: ethernet: ti: cpts: move dt props parsing to cpts driver Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:20 +0100
    Re: [PATCH  v2 08/13] net: ethernet: ti: cpts: move dt props parsing  to cpts driver Richard Cochran <richardcochran@gmail.com> - 2016-11-29 11:20 +0100
      Re: [PATCH v2 08/13] net: ethernet: ti: cpts: move dt props parsing  to cpts driver Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 17:00 +0100
  [PATCH  v2 05/13] net: ethernet: ti: cpts: fix registration order Grygorii Strashko <grygorii.strashko@ti.com> - 2016-11-29 00:20 +0100
    Re: [PATCH  v2 05/13] net: ethernet: ti: cpts: fix registration order Richard Cochran <richardcochran@gmail.com> - 2016-11-29 10:50 +0100

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