netxen: napi and irq cleanup

o separate and simpler irq handler for msi interrupts, avoids few checks
  than legacy mode.
o avoid redudant tx_has_work() and rx_has_work() checks in interrupt
  and napi, which can uncork irq based on racy (lockless) access to tx
  and rx ring indices. If we get interrupt, there's sufficient reason to
  schedule napi.
o replenish rx ring more often, remove self-imposed threshold rcv_free
  that prevents posting rx desc to card. This improves performance in
  low memory.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Tested-by: Vernon Mauery <mauery@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

4 files changed, 48 insertions, 163 deletions

diff --git a/drivers/net/netxen/netxen_nic.h b/drivers/net/netxen/netxen_nic.h
index 876cd0635f2e..8b6546ccb47b 100644
--- a/drivers/net/netxen/netxen_nic.h
+++ b/drivers/net/netxen/netxen_nic.h
@@ -842,7 +842,6 @@ struct netxen_rcv_desc_ctx {
         u32 flags;
         u32 producer;
         u32 rcv_pending;        /* Num of bufs posted in phantom */
-        u32 rcv_free;           /* Num of bufs in free list */
         dma_addr_t phys_addr;
         struct pci_dev *phys_pdev;
         struct rcv_desc *desc_head;     /* address of rx ring in Phantom */
@@ -1076,12 +1075,10 @@ void netxen_tso_check(struct netxen_adapter *adapter,
                       struct cmd_desc_type0 *desc, struct sk_buff *skb);
 int netxen_nic_hw_resources(struct netxen_adapter *adapter);
 void netxen_nic_clear_stats(struct netxen_adapter *adapter);
-int netxen_nic_rx_has_work(struct netxen_adapter *adapter);
-int netxen_nic_tx_has_work(struct netxen_adapter *adapter);
 void netxen_watchdog_task(struct work_struct *work);
 void netxen_post_rx_buffers(struct netxen_adapter *adapter, u32 ctx,
                             u32 ringid);
-int netxen_process_cmd_ring(unsigned long data);
+int netxen_process_cmd_ring(struct netxen_adapter *adapter);
 u32 netxen_process_rcv_ring(struct netxen_adapter *adapter, int ctx, int max);
 void netxen_nic_set_multi(struct net_device *netdev);
 int netxen_nic_change_mtu(struct net_device *netdev, int new_mtu);
diff --git a/drivers/net/netxen/netxen_nic_init.c b/drivers/net/netxen/netxen_nic_init.c
index 43eb1f65152d..64fc18d4afb6 100644
--- a/drivers/net/netxen/netxen_nic_init.c
+++ b/drivers/net/netxen/netxen_nic_init.c
@@ -185,7 +185,6 @@ void netxen_initialize_adapter_sw(struct netxen_adapter *adapter)
                 for (ring = 0; ring < NUM_RCV_DESC_RINGS; ring++) {
                         struct netxen_rx_buffer *rx_buf;
                         rcv_desc = &adapter->recv_ctx[ctxid].rcv_desc[ring];
-                        rcv_desc->rcv_free = rcv_desc->max_rx_desc_count;
                         rcv_desc->begin_alloc = 0;
                         rx_buf = rcv_desc->rx_buf_arr;
                         num_rx_bufs = rcv_desc->max_rx_desc_count;
@@ -976,28 +975,6 @@ int netxen_phantom_init(struct netxen_adapter *adapter, int pegtune_val)
         return 0;
 }
 
-int netxen_nic_rx_has_work(struct netxen_adapter *adapter)
-{
-        int ctx;
-
-        for (ctx = 0; ctx < MAX_RCV_CTX; ++ctx) {
-                struct netxen_recv_context *recv_ctx =
-                    &(adapter->recv_ctx[ctx]);
-                u32 consumer;
-                struct status_desc *desc_head;
-                struct status_desc *desc;
-
-                consumer = recv_ctx->status_rx_consumer;
-                desc_head = recv_ctx->rcv_status_desc_head;
-                desc = &desc_head[consumer];
-
-                if (netxen_get_sts_owner(desc) & STATUS_OWNER_HOST)
-                        return 1;
-        }
-
-        return 0;
-}
-
 static int netxen_nic_check_temp(struct netxen_adapter *adapter)
 {
         struct net_device *netdev = adapter->netdev;
@@ -1040,7 +1017,6 @@ static int netxen_nic_check_temp(struct netxen_adapter *adapter)
 
 void netxen_watchdog_task(struct work_struct *work)
 {
-        struct net_device *netdev;
         struct netxen_adapter *adapter =
                 container_of(work, struct netxen_adapter, watchdog_task);
 
@@ -1050,20 +1026,6 @@ void netxen_watchdog_task(struct work_struct *work)
         if (adapter->handle_phy_intr)
                 adapter->handle_phy_intr(adapter);
 
-        netdev = adapter->netdev;
-        if ((netif_running(netdev)) && !netif_carrier_ok(netdev) &&
-                        netxen_nic_link_ok(adapter) ) {
-                printk(KERN_INFO "%s %s (port %d), Link is up\n",
-                               netxen_nic_driver_name, netdev->name, adapter->portnum);
-                netif_carrier_on(netdev);
-                netif_wake_queue(netdev);
-        } else if(!(netif_running(netdev)) && netif_carrier_ok(netdev)) {
-                printk(KERN_ERR "%s %s Link is Down\n",
-                                netxen_nic_driver_name, netdev->name);
-                netif_carrier_off(netdev);
-                netif_stop_queue(netdev);
-        }
-
         mod_timer(&adapter->watchdog_timer, jiffies + 2 * HZ);
 }
 
@@ -1177,7 +1139,6 @@ static void netxen_process_rcv(struct netxen_adapter *adapter, int ctxid,
 
         netdev->last_rx = jiffies;
 
-        rcv_desc->rcv_free++;
         rcv_desc->rcv_pending--;
 
         /*
@@ -1202,13 +1163,6 @@ u32 netxen_process_rcv_ring(struct netxen_adapter *adapter, int ctxid, int max)
         u32 producer = 0;
         int count = 0, ring;
 
-        DPRINTK(INFO, "procesing receive\n");
-        /*
-         * we assume in this case that there is only one port and that is
-         * port #1...changes need to be done in firmware to indicate port
-         * number as part of the descriptor. This way we will be able to get
-         * the netdev which is associated with that device.
-         */
         while (count < max) {
                 desc = &desc_head[consumer];
                 if (!(netxen_get_sts_owner(desc) & STATUS_OWNER_HOST)) {
@@ -1221,10 +1175,8 @@ u32 netxen_process_rcv_ring(struct netxen_adapter *adapter, int ctxid, int max)
                 consumer = (consumer + 1) & (adapter->max_rx_desc_count - 1);
                 count++;
         }
-        if (count) {
-                for (ring = 0; ring < NUM_RCV_DESC_RINGS; ring++) {
-                        netxen_post_rx_buffers_nodb(adapter, ctxid, ring);
-                }
+        for (ring = 0; ring < NUM_RCV_DESC_RINGS; ring++) {
+                netxen_post_rx_buffers_nodb(adapter, ctxid, ring);
         }
 
         /* update the consumer index in phantom */
@@ -1235,20 +1187,18 @@ u32 netxen_process_rcv_ring(struct netxen_adapter *adapter, int ctxid, int max)
                 /* Window = 1 */
                 writel(consumer,
                        NETXEN_CRB_NORMALIZE(adapter,
-                                            recv_crb_registers[adapter->portnum].
+                                    recv_crb_registers[adapter->portnum].
                                             crb_rcv_status_consumer));
-                wmb();
         }
 
         return count;
 }
 
 /* Process Command status ring */
-int netxen_process_cmd_ring(unsigned long data)
+int netxen_process_cmd_ring(struct netxen_adapter *adapter)
 {
         u32 last_consumer;
         u32 consumer;
-        struct netxen_adapter *adapter = (struct netxen_adapter *)data;
         int count1 = 0;
         int count2 = 0;
         struct netxen_cmd_buffer *buffer;
@@ -1435,8 +1385,6 @@ void netxen_post_rx_buffers(struct netxen_adapter *adapter, u32 ctx, u32 ringid)
                 rcv_desc->begin_alloc = index;
                 rcv_desc->rcv_pending += count;
                 rcv_desc->producer = producer;
-                if (rcv_desc->rcv_free >= 32) {
-                        rcv_desc->rcv_free = 0;
                         /* Window = 1 */
                         writel((producer - 1) &
                                (rcv_desc->max_rx_desc_count - 1),
@@ -1460,8 +1408,6 @@ void netxen_post_rx_buffers(struct netxen_adapter *adapter, u32 ctx, u32 ringid)
                         writel(msg,
                                DB_NORMALIZE(adapter,
                                             NETXEN_RCV_PRODUCER_OFFSET));
-                        wmb();
-                }
         }
 }
 
@@ -1525,8 +1471,6 @@ static void netxen_post_rx_buffers_nodb(struct netxen_adapter *adapter,
                 rcv_desc->begin_alloc = index;
                 rcv_desc->rcv_pending += count;
                 rcv_desc->producer = producer;
-                if (rcv_desc->rcv_free >= 32) {
-                        rcv_desc->rcv_free = 0;
                         /* Window = 1 */
                         writel((producer - 1) &
                                (rcv_desc->max_rx_desc_count - 1),
@@ -1536,21 +1480,9 @@ static void netxen_post_rx_buffers_nodb(struct netxen_adapter *adapter,
                                                     rcv_desc_crb[ringid].
                                                     crb_rcv_producer_offset));
                         wmb();
-                }
         }
 }
 
-int netxen_nic_tx_has_work(struct netxen_adapter *adapter)
-{
-        if (find_diff_among(adapter->last_cmd_consumer,
-                            adapter->cmd_producer,
-                            adapter->max_tx_desc_count) > 0)
-                return 1;
-
-        return 0;
-}
-
-
 void netxen_nic_clear_stats(struct netxen_adapter *adapter)
 {
         memset(&adapter->stats, 0, sizeof(adapter->stats));
diff --git a/drivers/net/netxen/netxen_nic_isr.c b/drivers/net/netxen/netxen_nic_isr.c
index 48a404aa66ce..1a2333a52b5d 100644
--- a/drivers/net/netxen/netxen_nic_isr.c
+++ b/drivers/net/netxen/netxen_nic_isr.c
@@ -193,14 +193,14 @@ int netxen_nic_link_ok(struct netxen_adapter *adapter)
 void netxen_nic_xgbe_handle_phy_intr(struct netxen_adapter *adapter)
 {
         struct net_device *netdev = adapter->netdev;
-        u32 val, val1;
+        u32 val;
 
         /* WINDOW = 1 */
         val = readl(NETXEN_CRB_NORMALIZE(adapter, CRB_XG_STATE));
         val >>= (physical_port[adapter->portnum] * 8);
-        val1 = val & 0xff;
+        val &= 0xff;
 
-        if (adapter->ahw.xg_linkup == 1 && val1 != XG_LINK_UP) {
+        if (adapter->ahw.xg_linkup == 1 && val != XG_LINK_UP) {
                 printk(KERN_INFO "%s: %s NIC Link is down\n",
                        netxen_nic_driver_name, netdev->name);
                 adapter->ahw.xg_linkup = 0;
@@ -208,16 +208,7 @@ void netxen_nic_xgbe_handle_phy_intr(struct netxen_adapter *adapter)
                         netif_carrier_off(netdev);
                         netif_stop_queue(netdev);
                 }
-                /* read twice to clear sticky bits */
-                /* WINDOW = 0 */
-                netxen_nic_read_w0(adapter, NETXEN_NIU_XG_STATUS, &val1);
-                netxen_nic_read_w0(adapter, NETXEN_NIU_XG_STATUS, &val1);
-
-                if ((val & 0xffb) != 0xffb) {
-                        printk(KERN_INFO "%s ISR: Sync/Align BAD: 0x%08x\n",
-                               netxen_nic_driver_name, val1);
-                }
-        } else if (adapter->ahw.xg_linkup == 0 && val1 == XG_LINK_UP) {
+        } else if (adapter->ahw.xg_linkup == 0 && val == XG_LINK_UP) {
                 printk(KERN_INFO "%s: %s NIC Link is up\n",
                        netxen_nic_driver_name, netdev->name);
                 adapter->ahw.xg_linkup = 1;
diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index cd665da85c7f..95955204ef59 100644
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -63,12 +63,12 @@ static int netxen_nic_xmit_frame(struct sk_buff *, struct net_device *);
 static void netxen_tx_timeout(struct net_device *netdev);
 static void netxen_tx_timeout_task(struct work_struct *work);
 static void netxen_watchdog(unsigned long);
-static int netxen_handle_int(struct netxen_adapter *, struct net_device *);
 static int netxen_nic_poll(struct napi_struct *napi, int budget);
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void netxen_nic_poll_controller(struct net_device *netdev);
 #endif
 static irqreturn_t netxen_intr(int irq, void *data);
+static irqreturn_t netxen_msi_intr(int irq, void *data);
 
 int physical_port[] = {0, 1, 2, 3};
 
@@ -405,7 +405,7 @@ netxen_nic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
         netdev->set_mac_address    = netxen_nic_set_mac;
         netdev->change_mtu         = netxen_nic_change_mtu;
         netdev->tx_timeout         = netxen_tx_timeout;
-        netdev->watchdog_timeo     = HZ;
+        netdev->watchdog_timeo     = 2*HZ;
 
         netxen_nic_change_mtu(netdev, netdev->mtu);
 
@@ -823,6 +823,8 @@ static int netxen_nic_open(struct net_device *netdev)
         struct netxen_adapter *adapter = (struct netxen_adapter *)netdev->priv;
         int err = 0;
         int ctx, ring;
+        irq_handler_t handler;
+        unsigned long flags = IRQF_SAMPLE_RANDOM;
 
         if (adapter->is_up != NETXEN_ADAPTER_UP_MAGIC) {
                 err = netxen_init_firmware(adapter);
@@ -846,9 +848,14 @@ static int netxen_nic_open(struct net_device *netdev)
                                 netxen_post_rx_buffers(adapter, ctx, ring);
                 }
                 adapter->irq = adapter->ahw.pdev->irq;
-                err = request_irq(adapter->ahw.pdev->irq, netxen_intr,
-                                  IRQF_SHARED|IRQF_SAMPLE_RANDOM, netdev->name,
-                                  adapter);
+                if (adapter->flags & NETXEN_NIC_MSI_ENABLED)
+                        handler = netxen_msi_intr;
+                else {
+                        flags |= IRQF_SHARED;
+                        handler = netxen_intr;
+                }
+                err = request_irq(adapter->irq, handler,
+                                  flags, netdev->name, adapter);
                 if (err) {
                         printk(KERN_ERR "request_irq failed with: %d\n", err);
                         netxen_free_hw_resources(adapter);
@@ -857,21 +864,12 @@ static int netxen_nic_open(struct net_device *netdev)
 
                 adapter->is_up = NETXEN_ADAPTER_UP_MAGIC;
         }
-        if (!adapter->driver_mismatch)
-                mod_timer(&adapter->watchdog_timer, jiffies);
-
-        napi_enable(&adapter->napi);
-
-        netxen_nic_enable_int(adapter);
-
         /* Done here again so that even if phantom sw overwrote it,
          * we set it */
         if (adapter->init_port
             && adapter->init_port(adapter, adapter->portnum) != 0) {
-            del_timer_sync(&adapter->watchdog_timer);
                 printk(KERN_ERR "%s: Failed to initialize port %d\n",
                                 netxen_nic_driver_name, adapter->portnum);
-                napi_disable(&adapter->napi);
                 return -EIO;
         }
         if (adapter->macaddr_set)
@@ -884,6 +882,12 @@ static int netxen_nic_open(struct net_device *netdev)
                 adapter->set_mtu(adapter, netdev->mtu);
 
         if (!adapter->driver_mismatch)
+                mod_timer(&adapter->watchdog_timer, jiffies);
+
+        napi_enable(&adapter->napi);
+        netxen_nic_enable_int(adapter);
+
+        if (!adapter->driver_mismatch)
                 netif_start_queue(netdev);
 
         return 0;
@@ -1196,81 +1200,50 @@ static void netxen_tx_timeout_task(struct work_struct *work)
         netif_wake_queue(adapter->netdev);
 }
 
-static int
-netxen_handle_int(struct netxen_adapter *adapter, struct net_device *netdev)
+static inline void
+netxen_handle_int(struct netxen_adapter *adapter)
 {
-        u32 ret = 0;
-
-        DPRINTK(INFO, "Entered handle ISR\n");
-        adapter->stats.ints++;
-
         netxen_nic_disable_int(adapter);
-
-        if (netxen_nic_rx_has_work(adapter) || netxen_nic_tx_has_work(adapter)) {
-                if (netif_rx_schedule_prep(netdev, &adapter->napi)) {
-                        /*
-                         * Interrupts are already disabled.
-                         */
-                        __netif_rx_schedule(netdev, &adapter->napi);
-                } else {
-                        static unsigned int intcount = 0;
-                        if ((++intcount & 0xfff) == 0xfff)
-                                DPRINTK(KERN_ERR
-                                       "%s: %s interrupt %d while in poll\n",
-                                       netxen_nic_driver_name, netdev->name,
-                                       intcount);
-                }
-                ret = 1;
-        }
-
-        if (ret == 0) {
-                netxen_nic_enable_int(adapter);
-        }
-
-        return ret;
+        napi_schedule(&adapter->napi);
 }
 
-/*
- * netxen_intr - Interrupt Handler
- * @irq: interrupt number
- * data points to adapter stucture (which may be handling more than 1 port
- */
 irqreturn_t netxen_intr(int irq, void *data)
 {
         struct netxen_adapter *adapter = data;
-        struct net_device *netdev = adapter->netdev;
         u32 our_int = 0;
 
-        if (!(adapter->flags & NETXEN_NIC_MSI_ENABLED)) {
-                our_int = readl(NETXEN_CRB_NORMALIZE(adapter, CRB_INT_VECTOR));
-                /* not our interrupt */
-                if ((our_int & (0x80 << adapter->portnum)) == 0)
-                        return IRQ_NONE;
-        }
+        our_int = readl(NETXEN_CRB_NORMALIZE(adapter, CRB_INT_VECTOR));
+        /* not our interrupt */
+        if ((our_int & (0x80 << adapter->portnum)) == 0)
+                return IRQ_NONE;
 
         if (adapter->intr_scheme == INTR_SCHEME_PERPORT) {
                 /* claim interrupt */
-                if (!(adapter->flags & NETXEN_NIC_MSI_ENABLED)) {
-                        writel(our_int & ~((u32)(0x80 << adapter->portnum)),
+                writel(our_int & ~((u32)(0x80 << adapter->portnum)),
                         NETXEN_CRB_NORMALIZE(adapter, CRB_INT_VECTOR));
-                }
         }
 
-        if (netif_running(netdev))
-                netxen_handle_int(adapter, netdev);
+        netxen_handle_int(adapter);
 
         return IRQ_HANDLED;
 }
 
+irqreturn_t netxen_msi_intr(int irq, void *data)
+{
+        struct netxen_adapter *adapter = data;
+
+        netxen_handle_int(adapter);
+        return IRQ_HANDLED;
+}
+
 static int netxen_nic_poll(struct napi_struct *napi, int budget)
 {
         struct netxen_adapter *adapter = container_of(napi, struct netxen_adapter, napi);
-        struct net_device *netdev = adapter->netdev;
-        int done = 1;
+        int tx_complete;
         int ctx;
         int work_done;
 
-        DPRINTK(INFO, "polling for %d descriptors\n", *budget);
+        tx_complete = netxen_process_cmd_ring(adapter);
 
         work_done = 0;
         for (ctx = 0; ctx < MAX_RCV_CTX; ++ctx) {
@@ -1290,16 +1263,8 @@ static int netxen_nic_poll(struct napi_struct *napi, int budget)
                                                      budget / MAX_RCV_CTX);
         }
 
-        if (work_done >= budget)
-                done = 0;
-
-        if (netxen_process_cmd_ring((unsigned long)adapter) == 0)
-                done = 0;
-
-        DPRINTK(INFO, "new work_done: %d work_to_do: %d\n",
-                work_done, work_to_do);
-        if (done) {
-                netif_rx_complete(netdev, napi);
+        if ((work_done < budget) && tx_complete) {
+                netif_rx_complete(adapter->netdev, &adapter->napi);
                 netxen_nic_enable_int(adapter);
         }