@@ -32,6 +32,7 @@
*
* Consequently, we support none of these.
*/
+#include "linux/spinlock.h"
#include <linux/io.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/slab.h>
@@ -61,6 +62,8 @@ struct mvpp2_tai {
u64 period; // nanosecond period in 32.32 fixed point
/* This timestamp is updated every two seconds */
struct timespec64 stamp;
+ spinlock_t refcount_lock; /* Protects the poll_worker_refcount variable */
+ u16 poll_worker_refcount;
};
static void mvpp2_tai_modify(void __iomem *reg, u32 mask, u32 set)
@@ -370,16 +373,34 @@ void mvpp22_tai_tstamp(struct mvpp2_tai *tai, u32 tstamp,
void mvpp22_tai_start(struct mvpp2_tai *tai)
{
- long delay;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tai->refcount_lock, flags);
- delay = mvpp22_tai_aux_work(&tai->caps);
+ tai->poll_worker_refcount++;
+ if (tai->poll_worker_refcount > 1)
+ goto out_unlock;
- ptp_schedule_worker(tai->ptp_clock, delay);
+ ptp_schedule_worker(tai->ptp_clock, 0);
+
+out_unlock:
+ spin_unlock_irqrestore(&tai->refcount_lock, flags);
}
void mvpp22_tai_stop(struct mvpp2_tai *tai)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&tai->refcount_lock, flags);
+
+ tai->poll_worker_refcount--;
+ if (tai->poll_worker_refcount)
+ goto unlock_out;
+
ptp_cancel_worker_sync(tai->ptp_clock);
+
+unlock_out:
+ spin_unlock_irqrestore(&tai->refcount_lock, flags);
}
static void mvpp22_tai_remove(void *priv)
@@ -400,6 +421,7 @@ int mvpp22_tai_probe(struct device *dev, struct mvpp2 *priv)
return -ENOMEM;
spin_lock_init(&tai->lock);
+ spin_lock_init(&tai->refcount_lock);
tai->base = priv->iface_base;
In some configurations, a single TAI can be responsible for multiple mvpp2 interfaces. However, the mvpp2 driver will call mvpp22_tai_stop and mvpp22_tai_start per interface RX timestamp disable/enable. As a result, disabling timestamping for one interface would stop the worker and corrupt the other interface's RX timestamps. This commit solves the issue by introducing a simpler ref count for each TAI instance. Due to the ref count, we need now to lock tai->refcount_lock before doing anything. As a result, we can't call mvpp22_tai_do_aux_work as it will cause a deadlock. Therefore, we will just schedule the worker to start immediately. Fixes: ce3497e2072e ("net: mvpp2: ptp: add support for receive timestamping") Signed-off-by: Shmuel Hazan <shmuel.h@siklu.com> --- v1 -> v2: lock tai->lock before touching poll_worker_refcount. v2 -> v3: no change v3 -> v4: added additional lock for poll_worker_refcount due to a possible deadlock. --- .../net/ethernet/marvell/mvpp2/mvpp2_tai.c | 28 +++++++++++++++++-- 1 file changed, 25 insertions(+), 3 deletions(-)