nvethernet: add support for RIWT

This support enables the configuration of Receive Interrupt
Watchdog Timer register which indicates the watchdog timeout for
Receive Interrupt (RI) from the DMA.

Bug 200512422
Bug 2624476

Change-Id: I01bf170faa3c0f337d433eb19ebec49270483e18
Signed-off-by: Narayan Reddy <narayanr@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2139369
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

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

@@ -3017,6 +3017,22 @@ static int ether_parse_dt(struct ether_priv_data *pdata)
 		osi_core->dcs_en = OSI_DISABLE;
 	}
 
+	/* RIWT value to be set */
+	ret = of_property_read_u32(np, "nvidia,rx_riwt", &osi_dma->rx_riwt);
+	if (ret < 0) {
+		osi_dma->use_riwt = OSI_DISABLE;
+	} else {
+		if ((osi_dma->rx_riwt > OSI_MAX_RX_COALESCE_USEC) ||
+		    (osi_dma->rx_riwt < OSI_MIN_RX_COALESCE_USEC)) {
+			dev_err(dev,
+				"invalid rx_riwt, must be inrange %d to %d\n",
+				OSI_MIN_RX_COALESCE_USEC,
+				OSI_MAX_RX_COALESCE_USEC);
+			return -EINVAL;
+		}
+		osi_dma->use_riwt = OSI_ENABLE;
+	}
+
 	ret = ether_parse_phy_dt(pdata, np);
 	if (ret < 0) {
 		dev_err(dev, "failed to parse PHY DT\n");

drivers/net/ethernet/nvidia/nvethernet/ethtool.c

@@ -514,6 +514,102 @@ static int ether_get_ts_info(struct net_device *net,
 	return 0;
 }
 
+/**
+ *	ether_set_coalesce: Set interrupt coalescing parameters.
+ *	@dev: Net device data.
+ *	@ec: pointer to ethtool_coalesce structure
+ *
+ *	Algorithm: This function is invoked by kernel when user request to set
+ *	interrupt coalescing parameters. This driver maintains same coalescing
+ *	parameters for all the channels, hence same changes will be applied to
+ *	all the channels.
+ *
+ *	Dependencies:
+ *	1) Interface need to be bring down for setting these parameters
+ *
+ *	Protection: None.
+ *
+ *	Return: 0 on success and -ve number on failure.
+ */
+static int ether_set_coalesce(struct net_device *dev,
+			      struct ethtool_coalesce *ec)
+{
+	struct ether_priv_data *pdata = netdev_priv(dev);
+	struct osi_dma_priv_data *osi_dma = pdata->osi_dma;
+
+	if (netif_running(dev)) {
+		netdev_err(dev, "Coalesce parameters can be changed"
+			   " only if interface is down\n");
+		return -EINVAL;
+	}
+
+	/* Check for not supported parameters  */
+	if ((ec->rx_coalesce_usecs_irq) ||
+	    (ec->rx_max_coalesced_frames_irq) || (ec->tx_coalesce_usecs_irq) ||
+	    (ec->use_adaptive_rx_coalesce) || (ec->use_adaptive_tx_coalesce) ||
+	    (ec->pkt_rate_low) || (ec->rx_coalesce_usecs_low) ||
+	    (ec->rx_max_coalesced_frames_low) || (ec->tx_coalesce_usecs_high) ||
+	    (ec->tx_max_coalesced_frames_low) || (ec->pkt_rate_high) ||
+	    (ec->tx_coalesce_usecs_low) || (ec->rx_coalesce_usecs_high) ||
+	    (ec->rx_max_coalesced_frames_high) ||
+	    (ec->tx_max_coalesced_frames_irq)  ||
+	    (ec->stats_block_coalesce_usecs)   ||
+	    (ec->tx_max_coalesced_frames_high) || (ec->rate_sample_interval) ||
+	    (ec->tx_coalesce_usecs) || (ec->tx_max_coalesced_frames) ||
+	    (ec->rx_max_coalesced_frames)) {
+		return -EOPNOTSUPP;
+	}
+
+	if (ec->rx_coalesce_usecs == OSI_DISABLE) {
+		osi_dma->use_riwt = OSI_DISABLE;
+	} else if ((ec->rx_coalesce_usecs > OSI_MAX_RX_COALESCE_USEC) ||
+		   (ec->rx_coalesce_usecs < OSI_MIN_RX_COALESCE_USEC)) {
+		netdev_err(dev,
+			   "invalid rx_usecs, must be in a range of"
+			   " %d to %d usec\n", OSI_MIN_RX_COALESCE_USEC,
+			   OSI_MAX_RX_COALESCE_USEC);
+		return -EINVAL;
+	} else {
+		osi_dma->use_riwt = OSI_ENABLE;
+	}
+
+	netdev_err(dev, "RX COALESCING is %s\n", osi_dma->use_riwt ? "ENABLED" :
+		   "DISABLED");
+
+	osi_dma->rx_riwt = ec->rx_coalesce_usecs;
+
+	return 0;
+}
+
+/**
+ *	ether_get_coalesce: Set interrupt coalescing parameters.
+ *	@dev: Net device data.
+ *	@ec: pointer to ethtool_coalesce structure
+ *
+ *	Algorithm: This function is invoked by kernel when user request to get
+ *	interrupt coalescing parameters. As coalescing parameters are same
+ *	for all the channels, so this function will get coalescing
+ *	details from channel zero and return.
+ *
+ *	Dependencies:
+ *	1) MAC and PHY need to be initialized.
+ *
+ *	Protection: None.
+ *
+ *	Return: 0.
+ */
+static int ether_get_coalesce(struct net_device *dev,
+			      struct ethtool_coalesce *ec)
+{
+	struct ether_priv_data *pdata = netdev_priv(dev);
+	struct osi_dma_priv_data *osi_dma = pdata->osi_dma;
+
+	memset(ec, 0, sizeof(struct ethtool_coalesce));
+	ec->rx_coalesce_usecs = osi_dma->rx_riwt;
+
+	return 0;
+}
+
 static const struct ethtool_ops ether_ethtool_ops = {
 	.get_link = ethtool_op_get_link,
 	.get_link_ksettings = phy_ethtool_get_link_ksettings,
@@ -524,6 +620,8 @@ static const struct ethtool_ops ether_ethtool_ops = {
 	.get_strings = ether_get_strings,
 	.get_ethtool_stats = ether_get_ethtool_stats,
 	.get_sset_count = ether_get_sset_count,
+	.get_coalesce = ether_get_coalesce,
+	.set_coalesce = ether_set_coalesce,
 };
 
 /**

drivers/net/ethernet/nvidia/nvethernet/osd.c

@@ -188,8 +188,7 @@ static void ether_realloc_rx_skb(struct ether_priv_data *pdata,
 				osi_update_stats_counter(val, 1UL);
 			break;
 		}
-
+		osi_rx_dma_desc_init(rx_swcx, rx_desc, osi_dma->use_riwt);
-		osi_rx_dma_desc_init(rx_swcx, rx_desc);
 		INCR_RX_DESC_INDEX(rx_ring->refill_idx, 1U);
 	}