[PATCH net-next 4/9] ptp: ocp: forget a CPLD i2c adapter number that no longer resolves
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COLD24d
From: Sagi Maimon <hidden>
Date: 2026-09-22 14:28:45
Also in:
linux-doc, lkml
Subsystem:
networking drivers, opencompute ptp clock driver, ptp hardware clock support, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vadim Fedorenko, Richard Cochran, Linus Torvalds
adva_x1_bus_claim() returned -ENODEV when i2c_get_adapter() found nothing
for the cached number but left the number in place, so
adva_x1_cache_i2c_adap() kept bailing out on its first test and never
resolved the adapter again. The comment on the parent check claimed a bad
number is forgotten and looked up again on the next sweep; that only held
for a mismatched adapter, not for one that had gone away.
Factor the invalidation out and use it on both paths.
Re-arm the one-shot identification when a new adapter is cached as well: a
different adapter may answer where the previous one did not, and leaving
cpld_id_tried set kept cpld.id absent for the rest of the binding.
Fixes: 3b815e29966f ("ptp: ocp: add TAP CPLD access for ADVA TimeCard X1")
Signed-off-by: Sagi Maimon <redacted>
---
drivers/ptp/ptp_ocp.c | 35 ++++++++++++++++++++++++++++++-----
1 file changed, 30 insertions(+), 5 deletions(-)
diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index feb61355078a..45313143b6f7 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c@@ -4574,6 +4574,19 @@ static int adva_x1_i2c_adap_match(struct device *dev, const void *data) * both the notifier and a single lookup here can miss the same adapter. * Retrying costs a short klist walk per tick until one of them succeeds. */ +/* + * Forget the cached adapter number so the next sweep resolves it again. + * @nr < 0 forgets whatever is cached; otherwise only that number, so a + * caller that raced the notifier cannot clear a newer one. + */ +static void adva_x1_forget_i2c_adap(struct ptp_ocp *bp, int nr) +{ + scoped_guard(spinlock, &bp->cpld_adap_lock) { + if (nr < 0 || bp->cpld_i2c_adap_nr == nr) + bp->cpld_i2c_adap_nr = -1; + } +} + static void adva_x1_cache_i2c_adap(struct ptp_ocp *bp) { struct device *child;
@@ -4598,6 +4611,15 @@ static void adva_x1_cache_i2c_adap(struct ptp_ocp *bp) bp->cpld_i2c_adap_nr = i2c_verify_adapter(child)->nr; } + /* A different adapter may answer differently, so let the one-shot + * identification run again rather than leaving cpld.id absent for + * the rest of the binding. + */ + scoped_guard(mutex, &bp->cpld_lock) { + bp->cpld_id_tried = false; + bp->cpld_id_attempts = 0; + } + put_device(child); }
@@ -4614,8 +4636,14 @@ static int adva_x1_bus_claim(struct ptp_ocp *bp) lockdep_assert_held(&bp->cpld_lock); adap = i2c_get_adapter(READ_ONCE(bp->cpld_i2c_adap_nr)); - if (!adap) + if (!adap) { + /* The adapter behind the cached number is gone. Forget it, + * or adva_x1_cache_i2c_adap() keeps bailing out on its first + * test and never resolves the adapter again. + */ + adva_x1_forget_i2c_adap(bp, -1); return -ENODEV; + } /* The number is freed before the notifier clears it, so it can * already be another adapter's. Check this is still ours, and drop
@@ -4623,10 +4651,7 @@ static int adva_x1_bus_claim(struct ptp_ocp *bp) * way, where forgetting it lets the worker look the adapter up again. */ if (!bp->i2c_ctrl || adap->dev.parent != &bp->i2c_ctrl->dev) { - scoped_guard(spinlock, &bp->cpld_adap_lock) { - if (bp->cpld_i2c_adap_nr == adap->nr) - bp->cpld_i2c_adap_nr = -1; - } + adva_x1_forget_i2c_adap(bp, adap->nr); i2c_put_adapter(adap); return -ENODEV; }
--
2.47.0