net: systemport: Implement adaptive interrupt coalescing

Implement support for adaptive RX and TX interrupt coalescing using
net_dim. We have each of our TX ring and our single RX ring implement a
bcm_sysport_net_dim structure which holds an interrupt counter, number
of packets, bytes, and a container for a net_dim instance.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 140 insertions, 15 deletions

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index 3fc549b88c43..4e26f606a7f2 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/net_dim.h>
 #include <linux/etherdevice.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>
@@ -574,21 +575,55 @@ static int bcm_sysport_set_wol(struct net_device *dev,
         return 0;
 }
 
+static void bcm_sysport_set_rx_coalesce(struct bcm_sysport_priv *priv)
+{
+        u32 reg;
+
+        reg = rdma_readl(priv, RDMA_MBDONE_INTR);
+        reg &= ~(RDMA_INTR_THRESH_MASK |
+                 RDMA_TIMEOUT_MASK << RDMA_TIMEOUT_SHIFT);
+        reg |= priv->dim.coal_pkts;
+        reg |= DIV_ROUND_UP(priv->dim.coal_usecs * 1000, 8192) <<
+                            RDMA_TIMEOUT_SHIFT;
+        rdma_writel(priv, reg, RDMA_MBDONE_INTR);
+}
+
+static void bcm_sysport_set_tx_coalesce(struct bcm_sysport_tx_ring *ring)
+{
+        struct bcm_sysport_priv *priv = ring->priv;
+        u32 reg;
+
+        reg = tdma_readl(priv, TDMA_DESC_RING_INTR_CONTROL(ring->index));
+        reg &= ~(RING_INTR_THRESH_MASK |
+                 RING_TIMEOUT_MASK << RING_TIMEOUT_SHIFT);
+        reg |= ring->dim.coal_pkts;
+        reg |= DIV_ROUND_UP(ring->dim.coal_usecs * 1000, 8192) <<
+                            RING_TIMEOUT_SHIFT;
+        tdma_writel(priv, reg, TDMA_DESC_RING_INTR_CONTROL(ring->index));
+}
+
 static int bcm_sysport_get_coalesce(struct net_device *dev,
                                     struct ethtool_coalesce *ec)
 {
         struct bcm_sysport_priv *priv = netdev_priv(dev);
+        struct bcm_sysport_tx_ring *ring;
+        unsigned int i;
         u32 reg;
 
         reg = tdma_readl(priv, TDMA_DESC_RING_INTR_CONTROL(0));
 
         ec->tx_coalesce_usecs = (reg >> RING_TIMEOUT_SHIFT) * 8192 / 1000;
         ec->tx_max_coalesced_frames = reg & RING_INTR_THRESH_MASK;
+        for (i = 0; i < dev->num_tx_queues; i++) {
+                ring = &priv->tx_rings[i];
+                ec->use_adaptive_tx_coalesce |= ring->dim.use_dim;
+        }
 
         reg = rdma_readl(priv, RDMA_MBDONE_INTR);
 
         ec->rx_coalesce_usecs = (reg >> RDMA_TIMEOUT_SHIFT) * 8192 / 1000;
         ec->rx_max_coalesced_frames = reg & RDMA_INTR_THRESH_MASK;
+        ec->use_adaptive_rx_coalesce = priv->dim.use_dim;
 
         return 0;
 }
@@ -597,8 +632,8 @@ static int bcm_sysport_set_coalesce(struct net_device *dev,
                                     struct ethtool_coalesce *ec)
 {
         struct bcm_sysport_priv *priv = netdev_priv(dev);
+        struct bcm_sysport_tx_ring *ring;
         unsigned int i;
-        u32 reg;
 
         /* Base system clock is 125Mhz, DMA timeout is this reference clock
          * divided by 1024, which yield roughly 8.192 us, our maximum value has
@@ -615,22 +650,26 @@ static int bcm_sysport_set_coalesce(struct net_device *dev,
                 return -EINVAL;
 
         for (i = 0; i < dev->num_tx_queues; i++) {
-                reg = tdma_readl(priv, TDMA_DESC_RING_INTR_CONTROL(i));
-                reg &= ~(RING_INTR_THRESH_MASK |
-                         RING_TIMEOUT_MASK << RING_TIMEOUT_SHIFT);
-                reg |= ec->tx_max_coalesced_frames;
-                reg |= DIV_ROUND_UP(ec->tx_coalesce_usecs * 1000, 8192) <<
-                         RING_TIMEOUT_SHIFT;
-                tdma_writel(priv, reg, TDMA_DESC_RING_INTR_CONTROL(i));
+                ring = &priv->tx_rings[i];
+                ring->dim.coal_pkts = ec->tx_max_coalesced_frames;
+                ring->dim.coal_usecs = ec->tx_coalesce_usecs;
+                if (!ec->use_adaptive_tx_coalesce && ring->dim.use_dim) {
+                        ring->dim.coal_pkts = 1;
+                        ring->dim.coal_usecs = 0;
+                }
+                ring->dim.use_dim = ec->use_adaptive_tx_coalesce;
+                bcm_sysport_set_tx_coalesce(ring);
         }
 
-        reg = rdma_readl(priv, RDMA_MBDONE_INTR);
-        reg &= ~(RDMA_INTR_THRESH_MASK |
-                 RDMA_TIMEOUT_MASK << RDMA_TIMEOUT_SHIFT);
-        reg |= ec->rx_max_coalesced_frames;
-        reg |= DIV_ROUND_UP(ec->rx_coalesce_usecs * 1000, 8192) <<
-                            RDMA_TIMEOUT_SHIFT;
-        rdma_writel(priv, reg, RDMA_MBDONE_INTR);
+        priv->dim.coal_usecs = ec->rx_coalesce_usecs;
+        priv->dim.coal_pkts = ec->rx_max_coalesced_frames;
+
+        if (!ec->use_adaptive_rx_coalesce && priv->dim.use_dim) {
+                priv->dim.coal_pkts = 1;
+                priv->dim.coal_usecs = 0;
+        }
+        priv->dim.use_dim = ec->use_adaptive_rx_coalesce;
+        bcm_sysport_set_rx_coalesce(priv);
 
         return 0;
 }
@@ -709,6 +748,7 @@ static unsigned int bcm_sysport_desc_rx(struct bcm_sysport_priv *priv,
         struct bcm_sysport_stats64 *stats64 = &priv->stats64;
         struct net_device *ndev = priv->netdev;
         unsigned int processed = 0, to_process;
+        unsigned int processed_bytes = 0;
         struct bcm_sysport_cb *cb;
         struct sk_buff *skb;
         unsigned int p_index;
@@ -800,6 +840,7 @@ static unsigned int bcm_sysport_desc_rx(struct bcm_sysport_priv *priv,
                  */
                 skb_pull(skb, sizeof(*rsb) + 2);
                 len -= (sizeof(*rsb) + 2);
+                processed_bytes += len;
 
                 /* UniMAC may forward CRC */
                 if (priv->crc_fwd) {
@@ -824,6 +865,9 @@ next:
                         priv->rx_read_ptr = 0;
         }
 
+        priv->dim.packets = processed;
+        priv->dim.bytes = processed_bytes;
+
         return processed;
 }
 
@@ -896,6 +940,8 @@ static unsigned int __bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv,
         ring->packets += pkts_compl;
         ring->bytes += bytes_compl;
         u64_stats_update_end(&priv->syncp);
+        ring->dim.packets = pkts_compl;
+        ring->dim.bytes = bytes_compl;
 
         ring->c_index = c_index;
 
@@ -941,6 +987,7 @@ static int bcm_sysport_tx_poll(struct napi_struct *napi, int budget)
 {
         struct bcm_sysport_tx_ring *ring =
                 container_of(napi, struct bcm_sysport_tx_ring, napi);
+        struct net_dim_sample dim_sample;
         unsigned int work_done = 0;
 
         work_done = bcm_sysport_tx_reclaim(ring->priv, ring);
@@ -957,6 +1004,12 @@ static int bcm_sysport_tx_poll(struct napi_struct *napi, int budget)
                 return 0;
         }
 
+        if (ring->dim.use_dim) {
+                net_dim_sample(ring->dim.event_ctr, ring->dim.packets,
+                               ring->dim.bytes, &dim_sample);
+                net_dim(&ring->dim.dim, dim_sample);
+        }
+
         return budget;
 }
 
@@ -972,6 +1025,7 @@ static int bcm_sysport_poll(struct napi_struct *napi, int budget)
 {
         struct bcm_sysport_priv *priv =
                 container_of(napi, struct bcm_sysport_priv, napi);
+        struct net_dim_sample dim_sample;
         unsigned int work_done = 0;
 
         work_done = bcm_sysport_desc_rx(priv, budget);
@@ -994,6 +1048,12 @@ static int bcm_sysport_poll(struct napi_struct *napi, int budget)
                 intrl2_0_mask_clear(priv, INTRL2_0_RDMA_MBDONE);
         }
 
+        if (priv->dim.use_dim) {
+                net_dim_sample(priv->dim.event_ctr, priv->dim.packets,
+                               priv->dim.bytes, &dim_sample);
+                net_dim(&priv->dim.dim, dim_sample);
+        }
+
         return work_done;
 }
 
@@ -1012,6 +1072,40 @@ static void bcm_sysport_resume_from_wol(struct bcm_sysport_priv *priv)
         netif_dbg(priv, wol, priv->netdev, "resumed from WOL\n");
 }
 
+static void bcm_sysport_dim_work(struct work_struct *work)
+{
+        struct net_dim *dim = container_of(work, struct net_dim, work);
+        struct bcm_sysport_net_dim *ndim =
+                        container_of(dim, struct bcm_sysport_net_dim, dim);
+        struct bcm_sysport_priv *priv =
+                        container_of(ndim, struct bcm_sysport_priv, dim);
+        struct net_dim_cq_moder cur_profile =
+                                net_dim_get_profile(dim->mode, dim->profile_ix);
+
+        priv->dim.coal_usecs = cur_profile.usec;
+        priv->dim.coal_pkts = cur_profile.pkts;
+
+        bcm_sysport_set_rx_coalesce(priv);
+        dim->state = NET_DIM_START_MEASURE;
+}
+
+static void bcm_sysport_dim_tx_work(struct work_struct *work)
+{
+        struct net_dim *dim = container_of(work, struct net_dim, work);
+        struct bcm_sysport_net_dim *ndim =
+                        container_of(dim, struct bcm_sysport_net_dim, dim);
+        struct bcm_sysport_tx_ring *ring =
+                        container_of(ndim, struct bcm_sysport_tx_ring, dim);
+        struct net_dim_cq_moder cur_profile =
+                                net_dim_get_profile(dim->mode, dim->profile_ix);
+
+        ring->dim.coal_usecs = cur_profile.usec;
+        ring->dim.coal_pkts = cur_profile.pkts;
+
+        bcm_sysport_set_tx_coalesce(ring);
+        dim->state = NET_DIM_START_MEASURE;
+}
+
 /* RX and misc interrupt routine */
 static irqreturn_t bcm_sysport_rx_isr(int irq, void *dev_id)
 {
@@ -1030,6 +1124,7 @@ static irqreturn_t bcm_sysport_rx_isr(int irq, void *dev_id)
         }
 
         if (priv->irq0_stat & INTRL2_0_RDMA_MBDONE) {
+                priv->dim.event_ctr++;
                 if (likely(napi_schedule_prep(&priv->napi))) {
                         /* disable RX interrupts */
                         intrl2_0_mask_set(priv, INTRL2_0_RDMA_MBDONE);
@@ -1057,6 +1152,7 @@ static irqreturn_t bcm_sysport_rx_isr(int irq, void *dev_id)
                         continue;
 
                 txr = &priv->tx_rings[ring];
+                txr->dim.event_ctr++;
 
                 if (likely(napi_schedule_prep(&txr->napi))) {
                         intrl2_0_mask_set(priv, ring_bit);
@@ -1089,6 +1185,7 @@ static irqreturn_t bcm_sysport_tx_isr(int irq, void *dev_id)
                         continue;
 
                 txr = &priv->tx_rings[ring];
+                txr->dim.event_ctr++;
 
                 if (likely(napi_schedule_prep(&txr->napi))) {
                         intrl2_1_mask_set(priv, BIT(ring));
@@ -1354,6 +1451,16 @@ out:
                 phy_print_status(phydev);
 }
 
+static void bcm_sysport_init_dim(struct bcm_sysport_net_dim *dim,
+                                 void (*cb)(struct work_struct *work))
+{
+        INIT_WORK(&dim->dim.work, cb);
+        dim->dim.mode = NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE;
+        dim->event_ctr = 0;
+        dim->packets = 0;
+        dim->bytes = 0;
+}
+
 static int bcm_sysport_init_tx_ring(struct bcm_sysport_priv *priv,
                                     unsigned int index)
 {
@@ -1444,6 +1551,7 @@ static int bcm_sysport_init_tx_ring(struct bcm_sysport_priv *priv,
         reg |= (1 << index);
         tdma_writel(priv, reg, TDMA_TIER1_ARB_0_QUEUE_EN);
 
+        bcm_sysport_init_dim(&ring->dim, bcm_sysport_dim_tx_work);
         napi_enable(&ring->napi);
 
         netif_dbg(priv, hw, priv->netdev,
@@ -1474,6 +1582,7 @@ static void bcm_sysport_fini_tx_ring(struct bcm_sysport_priv *priv,
                 return;
 
         napi_disable(&ring->napi);
+        cancel_work_sync(&ring->dim.dim.work);
         netif_napi_del(&ring->napi);
 
         bcm_sysport_tx_clean(priv, ring);
@@ -1763,6 +1872,7 @@ static void bcm_sysport_netif_start(struct net_device *dev)
         struct bcm_sysport_priv *priv = netdev_priv(dev);
 
         /* Enable NAPI */
+        bcm_sysport_init_dim(&priv->dim, bcm_sysport_dim_work);
         napi_enable(&priv->napi);
 
         /* Enable RX interrupt and TX ring full interrupt */
@@ -1948,6 +2058,7 @@ static void bcm_sysport_netif_stop(struct net_device *dev)
         /* stop all software from updating hardware */
         netif_tx_stop_all_queues(dev);
         napi_disable(&priv->napi);
+        cancel_work_sync(&priv->dim.dim.work);
         phy_stop(dev->phydev);
 
         /* mask all interrupts */
diff --git a/drivers/net/ethernet/broadcom/bcmsysport.h b/drivers/net/ethernet/broadcom/bcmsysport.h
index 19c91c76e327..e1c97d4a82b4 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.h
+++ b/drivers/net/ethernet/broadcom/bcmsysport.h
@@ -12,6 +12,7 @@
 #define __BCM_SYSPORT_H
 
 #include <linux/if_vlan.h>
+#include <linux/net_dim.h>
 
 /* Receive/transmit descriptor format */
 #define DESC_ADDR_HI_STATUS_LEN 0x00
@@ -695,6 +696,16 @@ struct bcm_sysport_hw_params {
         unsigned int    num_rx_desc_words;
 };
 
+struct bcm_sysport_net_dim {
+        u16                     use_dim;
+        u16                     event_ctr;
+        unsigned long           packets;
+        unsigned long           bytes;
+        u32                     coal_usecs;
+        u32                     coal_pkts;
+        struct net_dim          dim;
+};
+
 /* Software view of the TX ring */
 struct bcm_sysport_tx_ring {
         spinlock_t      lock;           /* Ring lock for tx reclaim/xmit */
@@ -712,6 +723,7 @@ struct bcm_sysport_tx_ring {
         struct bcm_sysport_priv *priv;  /* private context backpointer */
         unsigned long   packets;        /* packets statistics */
         unsigned long   bytes;          /* bytes statistics */
+        struct bcm_sysport_net_dim dim; /* Net DIM context */
         unsigned int    switch_queue;   /* switch port queue number */
         unsigned int    switch_port;    /* switch port queue number */
         bool            inspect;        /* inspect switch port and queue */
@@ -743,6 +755,8 @@ struct bcm_sysport_priv {
         unsigned int            rx_read_ptr;
         unsigned int            rx_c_index;
 
+        struct bcm_sysport_net_dim      dim;
+
         /* PHY device */
         struct device_node      *phy_dn;
         phy_interface_t         phy_interface;