net: ti: prueth: Adds support for RX interrupt coalescing/pacing

Changes for supporting RX interrupt pacing feature using eCAP peripheral
available in PRU-ICSS.

Instead of interrupting the CPU for every packet received, the firmware
running on the PRU-ICSS will interrupt the CPU based on the configured
time period, if interrupt pacing is enabled.

The time period can be configured using ethtool.

RX pacing/coalescing is implemented Using eCAP timer events to give CPU
breathing space from ISR to perform other critical tasks.

The changes include new eCAP driver module which will initialization and
configures the ICSS eCAP HW.

Makefile and Kernel config has been updated to compile the eCAP driver
and to insert the module.

Signed-off-by: Murali Karicheri <[email protected]>
Signed-off-by: Basharath Hussain Khaja <[email protected]>
Signed-off-by: Parvathi Pudi <[email protected]>
Signed-off-by: NipaLocal <nipa@local>

Author: Murali Karicheri

drivers/net/ethernet/ti/Kconfig

@@ -229,6 +229,18 @@ config TI_ICSS_IEP
 	  To compile this driver as a module, choose M here. The module
 	  will be called icss_iep.
 
+config TI_PRUETH_ECAP
+	tristate "TI PRUETH ECAP driver"
+	depends on TI_PRUSS
+	default TI_PRUSS
+	help
+	  This enables support for the PRU-ICSS Enhanced Capture (eCAP) driver
+	  used for rx interrupt pacing support in PRU Driver/firmwares
+	  (Dual EMAC, HSR, PRP).
+
+	  To compile this driver as a module, choose M here. The module
+	  will be called prueth_ecap.
+
 config TI_PRUETH
 	tristate "TI PRU Ethernet EMAC driver"
 	depends on PRU_REMOTEPROC

drivers/net/ethernet/ti/Makefile

@@ -49,3 +49,5 @@ icssg-y := icssg/icssg_common.o \
 	   icssg/icssg_ethtool.o
 
 obj-$(CONFIG_TI_ICSS_IEP) += icssg/icss_iep.o
+
+obj-$(CONFIG_TI_PRUETH_ECAP) += icssm/icssm_prueth_ecap.o

drivers/net/ethernet/ti/icssm/icssm_ethtool.c

@@ -8,6 +8,7 @@
 #include <linux/if_bridge.h>
 #include <linux/if_vlan.h>
 #include "icssm_prueth.h"
+#include "icssm_prueth_ecap.h"
 #include "icssm_vlan_mcast_filter_mmap.h"
 #include "../icssg/icss_iep.h"
 
@@ -281,6 +282,40 @@ static int icssm_emac_get_ts_info(struct net_device *ndev,
 	return 0;
 }
 
+static int icssm_emac_get_coalesce(struct net_device *ndev,
+				   struct ethtool_coalesce *coal,
+				   struct kernel_ethtool_coalesce *kernel_coal,
+				   struct netlink_ext_ack *extack)
+{
+	struct prueth_emac *emac = netdev_priv(ndev);
+	struct prueth *prueth = emac->prueth;
+	struct prueth_ecap *ecap;
+
+	ecap = prueth->ecap;
+	if (IS_ERR(ecap))
+		return -EOPNOTSUPP;
+
+	return ecap->get_coalesce(emac, &coal->use_adaptive_rx_coalesce,
+				  &coal->rx_coalesce_usecs);
+}
+
+static int icssm_emac_set_coalesce(struct net_device *ndev,
+				   struct ethtool_coalesce *coal,
+				   struct kernel_ethtool_coalesce *kernel_coal,
+				   struct netlink_ext_ack *extack)
+{
+	struct prueth_emac *emac = netdev_priv(ndev);
+	struct prueth *prueth = emac->prueth;
+	struct prueth_ecap *ecap;
+
+	ecap = prueth->ecap;
+	if (IS_ERR(ecap))
+		return -EOPNOTSUPP;
+
+	return ecap->set_coalesce(emac, coal->use_adaptive_rx_coalesce,
+				  coal->rx_coalesce_usecs);
+}
+
 /* Ethtool support for EMAC adapter */
 const struct ethtool_ops emac_ethtool_ops = {
 	.get_drvinfo = icssm_emac_get_drvinfo,
@@ -295,5 +330,8 @@ const struct ethtool_ops emac_ethtool_ops = {
 	.get_rmon_stats = icssm_emac_get_rmon_stats,
 	.get_eth_mac_stats = icssm_emac_get_eth_mac_stats,
 	.get_ts_info = icssm_emac_get_ts_info,
+	.supported_coalesce_params = ETHTOOL_COALESCE_RX_USECS,
+	.get_coalesce = icssm_emac_get_coalesce,
+	.set_coalesce = icssm_emac_set_coalesce,
 };
 EXPORT_SYMBOL_GPL(emac_ethtool_ops);

drivers/net/ethernet/ti/icssm/icssm_prueth.c

@@ -30,6 +30,7 @@
 
 #include "icssm_prueth.h"
 #include "icssm_vlan_mcast_filter_mmap.h"
+#include "icssm_prueth_ecap.h"
 #include "../icssg/icssg_mii_rt.h"
 #include "../icssg/icss_iep.h"
 
@@ -1222,8 +1223,10 @@ static int icssm_emac_ndo_open(struct net_device *ndev)
 {
 	struct prueth_emac *emac = netdev_priv(ndev);
 	struct prueth *prueth = emac->prueth;
+	struct prueth_ecap *ecap;
 	int ret;
 
+	ecap = prueth->ecap;
 	/* set h/w MAC as user might have re-configured */
 	ether_addr_copy(emac->mac_addr, ndev->dev_addr);
 
@@ -1233,6 +1236,9 @@ static int icssm_emac_ndo_open(struct net_device *ndev)
 	icssm_prueth_emac_config(emac);
 
 	icssm_emac_set_stats(emac, &emac->stats);
+	/* initialize ecap for interrupt pacing */
+	if (!IS_ERR(ecap))
+		ecap->init(emac);
 
 	if (!prueth->emac_configured) {
 		icssm_iptp_dram_init(emac);
@@ -2179,12 +2185,25 @@ static int icssm_prueth_probe(struct platform_device *pdev)
 		goto netdev_exit;
 	}
 
+	/* Make rx interrupt pacing optional so that users can use ECAP for
+	 * other use cases if needed
+	 */
+	prueth->ecap = icssm_prueth_ecap_get(np);
+	if (IS_ERR(prueth->ecap)) {
+		ret = PTR_ERR(prueth->ecap);
+		if (ret != -EPROBE_DEFER)
+			dev_info(dev,
+				 "No ECAP. Rx interrupt pacing disabled\n");
+		else
+			goto iep_put;
+	}
+
 	/* register the network devices */
 	if (eth0_node) {
 		ret = register_netdev(prueth->emac[PRUETH_MAC0]->ndev);
 		if (ret) {
 			dev_err(dev, "can't register netdev for port MII0");
-			goto iep_put;
+			goto ecap_put;
 		}
 
 		prueth->registered_netdevs[PRUETH_MAC0] =
@@ -2220,6 +2239,10 @@ static int icssm_prueth_probe(struct platform_device *pdev)
 		unregister_netdev(prueth->registered_netdevs[i]);
 	}
 
+ecap_put:
+	if (!IS_ERR(prueth->ecap))
+		icssm_prueth_ecap_put(prueth->ecap);
+
 iep_put:
 	icss_iep_put(prueth->iep);
 

drivers/net/ethernet/ti/icssm/icssm_prueth.h

@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/pruss_driver.h>
 #include <linux/remoteproc/pruss.h>
+#include <linux/netdevice.h>
 
 #include "icssm_switch.h"
 #include "icssm_prueth_ptp.h"
@@ -403,6 +404,7 @@ struct prueth {
 	struct regmap *mii_rt;
 	struct icss_iep *iep;
 
+	struct prueth_ecap *ecap;
 	const struct prueth_private_data *fw_data;
 	struct prueth_fw_offsets *fw_offsets;
 
@@ -412,6 +414,7 @@ struct prueth {
 
 	unsigned int eth_type;
 	size_t ocmc_ram_size;
+	struct mutex mlock; /* serialize access */
 	u8 emac_configured;
 	u8 base_mac[ETH_ALEN];
 };