nvethernet: consume the timestamp if available in tx done

Issue: Observed Tx timestamp timeout from application since
workqueue is not getting scheduled at the driver layer to consume
the Tx timestamp from the OSI layer which resulted in tx_timeout
from APP layer.

Fix: Invoke the timestamp consume function in tx done instead
of scheduling through workqueue. Schedule the work queue only
if the timestamp is not found.

Bug 3658701

Change-Id: If97aebc1980f685e3cc34f135ace91298ee78657
Signed-off-by: Bhadram Varka <vbhadram@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2732444
Reviewed-by: Troy Kong <troyk@nvidia.com>
Reviewed-by: Narayan Reddy <narayanr@nvidia.com>
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svc_kernel_abi <svc_kernel_abi@nvidia.com>
Reviewed-by: Rakesh Goyal <rgoyal@nvidia.com>
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>
Tested-by: Troy Kong <troyk@nvidia.com>
GVS: Gerrit_Virtual_Submit

drivers/net/ethernet/nvidia/nvethernet/ether_linux.h

@@ -125,11 +125,6 @@
  */
 #define ETHER_DEFAULT_PTP_QUEUE		3U
 
-/**
- * @brief  TX timestamp miss threshold
- */
-#define TS_MISS_THRESHOLD		200U
-
 /**
  * @brief SEC to MSEC converter
  */
@@ -626,6 +621,8 @@ struct ether_priv_data {
 #endif
 	/** Protect critical section of TX TS SKB list */
 	raw_spinlock_t txts_lock;
+	/** Ref count for ether_get_tx_ts_func */
+	atomic_t tx_ts_ref_cnt;
 };
 
 /**
@@ -800,6 +797,18 @@ int ether_tc_setup_cbs(struct ether_priv_data *pdata,
 		       struct tc_cbs_qopt_offload *qopt);
 
 #endif
+
+/**
+ * @brief Get Tx done timestamp from OSI and update in skb
+ *
+ * @param[in] pdata: Pointer to private data structure.
+ *
+ * @note Network interface should be up
+ *
+ * @retval 0 on success
+ * @retval EAGAIN on Failure
+ */
+int ether_get_tx_ts(struct ether_priv_data *pdata);
 #ifdef ETHER_NVGRO
 void ether_nvgro_purge_timer(struct timer_list *t);
 #endif /* ETHER_NVGRO */