[PATCH v2 2/3] net: ethernet: ti: cpts: convert to use ptp auxiliary worker

[Grygorii Strashko]

There could be significant delay in CPTS work schedule under high system
load and on -RT which could cause CPTS misbehavior due to internal counter
overflow. Usage of own kthread_worker allows to avoid such kind of issues
and makes it possible to tune priority of CPTS kthread_worker thread on -RT.

Hence, the CPTS driver is converted to use PTP auxiliary worker as PHC
subsystem implements such functionality in a generic way now.

Signed-off-by: Grygorii Strashko <grygorii.stras...@ti.com>
---
 drivers/net/ethernet/ti/cpts.c | 27 +++++++++++++--------------
 drivers/net/ethernet/ti/cpts.h |  1 -
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index 32279d2..3ed438e 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -224,6 +224,17 @@ static int cpts_ptp_enable(struct ptp_clock_info *ptp,
        return -EOPNOTSUPP;
 }
 
+static long cpts_overflow_check(struct ptp_clock_info *ptp)
+{
+       struct cpts *cpts = container_of(ptp, struct cpts, info);
+       unsigned long delay = cpts->ov_check_period;
+       struct timespec64 ts;
+
+       cpts_ptp_gettime(&cpts->info, &ts);
+       pr_debug("cpts overflow check at %lld.%09lu\n", ts.tv_sec, ts.tv_nsec);
+       return (long)delay;
+}
+
 static struct ptp_clock_info cpts_info = {
        .owner          = THIS_MODULE,
        .name           = "CTPS timer",
@@ -236,18 +247,9 @@ static struct ptp_clock_info cpts_info = {
        .gettime64      = cpts_ptp_gettime,
        .settime64      = cpts_ptp_settime,
        .enable         = cpts_ptp_enable,
+       .do_aux_work    = cpts_overflow_check,
 };
 
-static void cpts_overflow_check(struct work_struct *work)
-{
-       struct timespec64 ts;
-       struct cpts *cpts = container_of(work, struct cpts, overflow_work.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->ov_check_period);
-}
-
 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
                      u16 ts_seqid, u8 ts_msgtype)
 {
@@ -378,7 +380,7 @@ int cpts_register(struct cpts *cpts)
        }
        cpts->phc_index = ptp_clock_index(cpts->clock);
 
-       schedule_delayed_work(&cpts->overflow_work, cpts->ov_check_period);
+       ptp_schedule_worker(cpts->clock, cpts->ov_check_period);
        return 0;
 
 err_ptp:
@@ -392,8 +394,6 @@ void cpts_unregister(struct cpts *cpts)
        if (WARN_ON(!cpts->clock))
                return;
 
-       cancel_delayed_work_sync(&cpts->overflow_work);
-
        ptp_clock_unregister(cpts->clock);
        cpts->clock = NULL;
 
@@ -476,7 +476,6 @@ struct cpts *cpts_create(struct device *dev, void __iomem 
*regs,
        cpts->dev = dev;
        cpts->reg = (struct cpsw_cpts __iomem *)regs;
        spin_lock_init(&cpts->lock);
-       INIT_DELAYED_WORK(&cpts->overflow_work, cpts_overflow_check);
 
        ret = cpts_of_parse(cpts, node);
        if (ret)
diff --git a/drivers/net/ethernet/ti/cpts.h b/drivers/net/ethernet/ti/cpts.h
index 01ea82b..586edd9 100644
--- a/drivers/net/ethernet/ti/cpts.h
+++ b/drivers/net/ethernet/ti/cpts.h
@@ -119,7 +119,6 @@ struct cpts {
        u32 cc_mult; /* for the nominal frequency */
        struct cyclecounter cc;
        struct timecounter tc;
-       struct delayed_work overflow_work;
        int phc_index;
        struct clk *refclk;
        struct list_head events;
-- 
2.10.1