[RFC PATCH 2/2] net: mvneta: Add naive RSS support

[Gregory CLEMENT <gregory.clement@free-electrons.com>]

This patch add the support for the RSS related ethtool
function. Currently it only use one entry in the indirection table which
allows associating an mveneta interface to a given CPU.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
---
 drivers/net/ethernet/marvell/mvneta.c | 114 ++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index c38326b848f9..5f810a458443 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -259,6 +259,11 @@
 
 #define MVNETA_TX_MTU_MAX		0x3ffff
 
+/* The RSS lookup table actually has 256 entries but we do not use
+ * them yet
+ */
+#define MVNETA_RSS_LU_TABLE_SIZE	1
+
 /* TSO header size */
 #define TSO_HEADER_SIZE 128
 
@@ -380,6 +385,8 @@ struct mvneta_port {
 	int use_inband_status:1;
 
 	u64 ethtool_stats[ARRAY_SIZE(mvneta_statistics)];
+
+	u32 indir[MVNETA_RSS_LU_TABLE_SIZE];
 };
 
 /* The mvneta_tx_desc and mvneta_rx_desc structures describe the
@@ -3173,6 +3180,107 @@ static int mvneta_ethtool_get_sset_count(struct net_device *dev, int sset)
 	return -EOPNOTSUPP;
 }
 
+static u32 mvneta_ethtool_get_rxfh_indir_size(struct net_device *dev)
+{
+	return MVNETA_RSS_LU_TABLE_SIZE;
+}
+
+static int mvneta_ethtool_get_rxnfc(struct net_device *dev,
+				    struct ethtool_rxnfc *info,
+				    u32 *rules __always_unused)
+{
+	switch (info->cmd) {
+	case ETHTOOL_GRXRINGS:
+		info->data =  rxq_number;
+		return 0;
+	case ETHTOOL_GRXFH:
+		return -EOPNOTSUPP;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int  mvneta_config_rss(struct mvneta_port *pp)
+{
+	int cpu;
+	u32 val;
+
+	netif_tx_stop_all_queues(pp->dev);
+
+	/* Mask all ethernet port interrupts */
+	mvreg_write(pp, MVNETA_INTR_NEW_MASK, 0);
+	mvreg_write(pp, MVNETA_INTR_OLD_MASK, 0);
+	mvreg_write(pp, MVNETA_INTR_MISC_MASK, 0);
+
+	/* We have to synchronise on the napi of each CPU */
+	for_each_online_cpu(cpu) {
+		struct mvneta_pcpu_port *pcpu_port =
+			per_cpu_ptr(pp->ports, cpu);
+
+		napi_synchronize(&pcpu_port->napi);
+		napi_disable(&pcpu_port->napi);
+	}
+
+	pp->rxq_def = pp->indir[0];
+
+	/* update unicast mapping */
+	mvneta_set_rx_mode(pp->dev);
+
+	/* Update val of portCfg register accordingly with all RxQueue types */
+	val = MVNETA_PORT_CONFIG_DEFL_VALUE(pp->rxq_def);
+	mvreg_write(pp, MVNETA_PORT_CONFIG, val);
+
+	/* Update the elected CPU matching the new rxq_def */
+	mvneta_percpu_elect(pp);
+
+	/* We have to synchronise on the napi of each CPU */
+	for_each_online_cpu(cpu) {
+		struct mvneta_pcpu_port *pcpu_port =
+			per_cpu_ptr(pp->ports, cpu);
+
+		napi_enable(&pcpu_port->napi);
+	}
+
+	netif_tx_start_all_queues(pp->dev);
+
+	return 0;
+}
+
+static int mvneta_ethtool_set_rxfh(struct net_device *dev, const u32 *indir,
+				   const u8 *key, const u8 hfunc)
+{
+	struct mvneta_port *pp = netdev_priv(dev);
+	/* We require at least one supported parameter to be changed
+	* and no change in any of the unsupported parameters
+	*/
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+
+	if (!indir)
+		return 0;
+
+	memcpy(pp->indir, indir, MVNETA_RSS_LU_TABLE_SIZE);
+
+	return mvneta_config_rss(pp);
+}
+
+static int mvneta_ethtool_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
+				   u8 *hfunc)
+{
+	struct mvneta_port *pp = netdev_priv(dev);
+
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+
+	if (!indir)
+		return 0;
+
+	memcpy(indir, pp->indir, MVNETA_RSS_LU_TABLE_SIZE);
+
+	return 0;
+}
+
 static const struct net_device_ops mvneta_netdev_ops = {
 	.ndo_open            = mvneta_open,
 	.ndo_stop            = mvneta_stop,
@@ -3197,6 +3305,10 @@ const struct ethtool_ops mvneta_eth_tool_ops = {
 	.get_strings	= mvneta_ethtool_get_strings,
 	.get_ethtool_stats = mvneta_ethtool_get_stats,
 	.get_sset_count	= mvneta_ethtool_get_sset_count,
+	.get_rxfh_indir_size = mvneta_ethtool_get_rxfh_indir_size,
+	.get_rxnfc	= mvneta_ethtool_get_rxnfc,
+	.get_rxfh	= mvneta_ethtool_get_rxfh,
+	.set_rxfh	= mvneta_ethtool_set_rxfh,
 };
 
 /* Initialize hw */
@@ -3389,6 +3501,8 @@ static int mvneta_probe(struct platform_device *pdev)
 
 	pp->rxq_def = rxq_def;
 
+	pp->indir[0] = rxq_def;
+
 	pp->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(pp->clk)) {
 		err = PTR_ERR(pp->clk);
-- 
2.5.0