amd-xgbe: Provide support for receive side scaling

This patch provides support for receive side scaling (RSS). RSS allows
for spreading incoming network packets across the Rx queues.  When used
in conjunction with the per DMA channel interrupt support, this allows
the receive processing to be spread across multiple processors.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 147 insertions, 1 deletions

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
index ac3d319..551794c 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
@@ -351,6 +351,127 @@ static void xgbe_config_sph_mode(struct xgbe_prv_data *pdata)
 	XGMAC_IOWRITE_BITS(pdata, MAC_RCR, HDSMS, XGBE_SPH_HDSMS_SIZE);
 }
 
+static int xgbe_write_rss_reg(struct xgbe_prv_data *pdata, unsigned int type,
+			      unsigned int index, unsigned int val)
+{
+	unsigned int wait;
+	int ret = 0;
+
+	mutex_lock(&pdata->rss_mutex);
+
+	if (XGMAC_IOREAD_BITS(pdata, MAC_RSSAR, OB)) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+
+	XGMAC_IOWRITE(pdata, MAC_RSSDR, val);
+
+	XGMAC_IOWRITE_BITS(pdata, MAC_RSSAR, RSSIA, index);
+	XGMAC_IOWRITE_BITS(pdata, MAC_RSSAR, ADDRT, type);
+	XGMAC_IOWRITE_BITS(pdata, MAC_RSSAR, CT, 0);
+	XGMAC_IOWRITE_BITS(pdata, MAC_RSSAR, OB, 1);
+
+	wait = 1000;
+	while (wait--) {
+		if (!XGMAC_IOREAD_BITS(pdata, MAC_RSSAR, OB))
+			goto unlock;
+
+		usleep_range(1000, 1500);
+	}
+
+	ret = -EBUSY;
+
+unlock:
+	mutex_unlock(&pdata->rss_mutex);
+
+	return ret;
+}
+
+static int xgbe_write_rss_hash_key(struct xgbe_prv_data *pdata)
+{
+	unsigned int key_regs = sizeof(pdata->rss_key) / sizeof(u32);
+	unsigned int *key = (unsigned int *)&pdata->rss_key;
+	int ret;
+
+	while (key_regs--) {
+		ret = xgbe_write_rss_reg(pdata, XGBE_RSS_HASH_KEY_TYPE,
+					 key_regs, *key++);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int xgbe_write_rss_lookup_table(struct xgbe_prv_data *pdata)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(pdata->rss_table); i++) {
+		ret = xgbe_write_rss_reg(pdata,
+					 XGBE_RSS_LOOKUP_TABLE_TYPE, i,
+					 pdata->rss_table[i]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int xgbe_enable_rss(struct xgbe_prv_data *pdata)
+{
+	int ret;
+
+	if (!pdata->hw_feat.rss)
+		return -EOPNOTSUPP;
+
+	/* Program the hash key */
+	ret = xgbe_write_rss_hash_key(pdata);
+	if (ret)
+		return ret;
+
+	/* Program the lookup table */
+	ret = xgbe_write_rss_lookup_table(pdata);
+	if (ret)
+		return ret;
+
+	/* Set the RSS options */
+	XGMAC_IOWRITE(pdata, MAC_RSSCR, pdata->rss_options);
+
+	/* Enable RSS */
+	XGMAC_IOWRITE_BITS(pdata, MAC_RSSCR, RSSE, 1);
+
+	return 0;
+}
+
+static int xgbe_disable_rss(struct xgbe_prv_data *pdata)
+{
+	if (!pdata->hw_feat.rss)
+		return -EOPNOTSUPP;
+
+	XGMAC_IOWRITE_BITS(pdata, MAC_RSSCR, RSSE, 0);
+
+	return 0;
+}
+
+static void xgbe_config_rss(struct xgbe_prv_data *pdata)
+{
+	int ret;
+
+	if (!pdata->hw_feat.rss)
+		return;
+
+	if (pdata->netdev->features & NETIF_F_RXHASH)
+		ret = xgbe_enable_rss(pdata);
+	else
+		ret = xgbe_disable_rss(pdata);
+
+	if (ret)
+		netdev_err(pdata->netdev,
+			   "error configuring RSS, RSS disabled\n");
+}
+
 static int xgbe_disable_tx_flow_control(struct xgbe_prv_data *pdata)
 {
 	unsigned int max_q_count, q_count;
@@ -1408,7 +1529,7 @@ static int xgbe_dev_read(struct xgbe_channel *channel)
 	struct xgbe_ring_desc *rdesc;
 	struct xgbe_packet_data *packet = &ring->packet_data;
 	struct net_device *netdev = channel->pdata->netdev;
-	unsigned int err, etlt;
+	unsigned int err, etlt, l34t;
 
 	DBGPR("-->xgbe_dev_read: cur = %d\n", ring->cur);
 
@@ -1447,6 +1568,26 @@ static int xgbe_dev_read(struct xgbe_channel *channel)
 		rdata->hdr_len = XGMAC_GET_BITS_LE(rdesc->desc2,
 						   RX_NORMAL_DESC2, HL);
 
+	/* Get the RSS hash */
+	if (XGMAC_GET_BITS_LE(rdesc->desc3, RX_NORMAL_DESC3, RSV)) {
+		XGMAC_SET_BITS(packet->attributes, RX_PACKET_ATTRIBUTES,
+			       RSS_HASH, 1);
+
+		packet->rss_hash = le32_to_cpu(rdesc->desc1);
+
+		l34t = XGMAC_GET_BITS_LE(rdesc->desc3, RX_NORMAL_DESC3, L34T);
+		switch (l34t) {
+		case RX_DESC3_L34T_IPV4_TCP:
+		case RX_DESC3_L34T_IPV4_UDP:
+		case RX_DESC3_L34T_IPV6_TCP:
+		case RX_DESC3_L34T_IPV6_UDP:
+			packet->rss_hash_type = PKT_HASH_TYPE_L4;
+
+		default:
+			packet->rss_hash_type = PKT_HASH_TYPE_L3;
+		}
+	}
+
 	/* Get the packet length */
 	rdata->len = XGMAC_GET_BITS_LE(rdesc->desc3, RX_NORMAL_DESC3, PL);
 
@@ -2479,6 +2620,7 @@ static int xgbe_init(struct xgbe_prv_data *pdata)
 	xgbe_config_rx_buffer_size(pdata);
 	xgbe_config_tso_mode(pdata);
 	xgbe_config_sph_mode(pdata);
+	xgbe_config_rss(pdata);
 	desc_if->wrapper_tx_desc_init(pdata);
 	desc_if->wrapper_rx_desc_init(pdata);
 	xgbe_enable_dma_interrupts(pdata);
@@ -2614,5 +2756,9 @@ void xgbe_init_function_ptrs_dev(struct xgbe_hw_if *hw_if)
 	hw_if->config_dcb_tc = xgbe_config_dcb_tc;
 	hw_if->config_dcb_pfc = xgbe_config_dcb_pfc;
 
+	/* For Receive Side Scaling */
+	hw_if->enable_rss = xgbe_enable_rss;
+	hw_if->disable_rss = xgbe_disable_rss;
+
 	DBGPR("<--xgbe_init_function_ptrs\n");
 }