1 files changed, 63 insertions, 9 deletions

diff --git a/drivers/net/e100.c b/drivers/net/e100.c
index 6169663..763810c 100644
--- a/drivers/net/e100.c
+++ b/drivers/net/e100.c
@@ -285,6 +285,12 @@ enum scb_status {
 	rus_mask         = 0x3C,
 };
 
+enum ru_state  {
+	RU_SUSPENDED = 0,
+	RU_RUNNING	 = 1,
+	RU_UNINITIALIZED = -1,
+};
+
 enum scb_stat_ack {
 	stat_ack_not_ours    = 0x00,
 	stat_ack_sw_gen      = 0x04,
@@ -526,6 +532,7 @@ struct nic {
 	struct rx *rx_to_use;
 	struct rx *rx_to_clean;
 	struct rfd blank_rfd;
+	enum ru_state ru_running;
 
 	spinlock_t cb_lock			____cacheline_aligned;
 	spinlock_t cmd_lock;
@@ -947,7 +954,7 @@ static void e100_get_defaults(struct nic *nic)
 		((nic->mac >= mac_82558_D101_A4) ? cb_cid : cb_i));
 
 	/* Template for a freshly allocated RFD */
-	nic->blank_rfd.command = cpu_to_le16(cb_el & cb_s);
+	nic->blank_rfd.command = cpu_to_le16(cb_el);
 	nic->blank_rfd.rbd = 0xFFFFFFFF;
 	nic->blank_rfd.size = cpu_to_le16(VLAN_ETH_FRAME_LEN);
 
@@ -1742,11 +1749,19 @@ static int e100_alloc_cbs(struct nic *nic)
 	return 0;
 }
 
-static inline void e100_start_receiver(struct nic *nic)
+static inline void e100_start_receiver(struct nic *nic, struct rx *rx)
 {
-	/* Start if RFA is non-NULL */
-	if(nic->rx_to_clean->skb)
-		e100_exec_cmd(nic, ruc_start, nic->rx_to_clean->dma_addr);
+	if(!nic->rxs) return;
+	if(RU_SUSPENDED != nic->ru_running) return;
+
+	/* handle init time starts */
+	if(!rx) rx = nic->rxs;
+
+	/* (Re)start RU if suspended or idle and RFA is non-NULL */
+	if(rx->skb) {
+		e100_exec_cmd(nic, ruc_start, rx->dma_addr);
+		nic->ru_running = RU_RUNNING;
+	}
 }
 
 #define RFD_BUF_LEN (sizeof(struct rfd) + VLAN_ETH_FRAME_LEN)
@@ -1775,7 +1790,7 @@ static int e100_rx_alloc_skb(struct nic *nic, struct rx *rx)
 		put_unaligned(cpu_to_le32(rx->dma_addr),
 			(u32 *)&prev_rfd->link);
 		wmb();
-		prev_rfd->command &= ~cpu_to_le16(cb_el & cb_s);
+		prev_rfd->command &= ~cpu_to_le16(cb_el);
 		pci_dma_sync_single_for_device(nic->pdev, rx->prev->dma_addr,
 			sizeof(struct rfd), PCI_DMA_TODEVICE);
 	}
@@ -1813,6 +1828,10 @@ static int e100_rx_indicate(struct nic *nic, struct rx *rx,
 	pci_unmap_single(nic->pdev, rx->dma_addr,
 		RFD_BUF_LEN, PCI_DMA_FROMDEVICE);
 
+	/* this allows for a fast restart without re-enabling interrupts */
+	if(le16_to_cpu(rfd->command) & cb_el)
+		nic->ru_running = RU_SUSPENDED;
+
 	/* Pull off the RFD and put the actual data (minus eth hdr) */
 	skb_reserve(skb, sizeof(struct rfd));
 	skb_put(skb, actual_size);
@@ -1843,18 +1862,45 @@ static void e100_rx_clean(struct nic *nic, unsigned int *work_done,
 	unsigned int work_to_do)
 {
 	struct rx *rx;
+	int restart_required = 0;
+	struct rx *rx_to_start = NULL;
+
+	/* are we already rnr? then pay attention!!! this ensures that
+	 * the state machine progression never allows a start with a
+	 * partially cleaned list, avoiding a race between hardware
+	 * and rx_to_clean when in NAPI mode */
+	if(RU_SUSPENDED == nic->ru_running)
+		restart_required = 1;
 
 	/* Indicate newly arrived packets */
 	for(rx = nic->rx_to_clean; rx->skb; rx = nic->rx_to_clean = rx->next) {
-		if(e100_rx_indicate(nic, rx, work_done, work_to_do))
+		int err = e100_rx_indicate(nic, rx, work_done, work_to_do);
+		if(-EAGAIN == err) {
+			/* hit quota so have more work to do, restart once
+			 * cleanup is complete */
+			restart_required = 0;
+			break;
+		} else if(-ENODATA == err)
 			break; /* No more to clean */
 	}
 
+	/* save our starting point as the place we'll restart the receiver */
+	if(restart_required)
+		rx_to_start = nic->rx_to_clean;
+
 	/* Alloc new skbs to refill list */
 	for(rx = nic->rx_to_use; !rx->skb; rx = nic->rx_to_use = rx->next) {
 		if(unlikely(e100_rx_alloc_skb(nic, rx)))
 			break; /* Better luck next time (see watchdog) */
 	}
+
+	if(restart_required) {
+		// ack the rnr?
+		writeb(stat_ack_rnr, &nic->csr->scb.stat_ack);
+		e100_start_receiver(nic, rx_to_start);
+		if(work_done)
+			(*work_done)++;
+	}
 }
 
 static void e100_rx_clean_list(struct nic *nic)
@@ -1862,6 +1908,8 @@ static void e100_rx_clean_list(struct nic *nic)
 	struct rx *rx;
 	unsigned int i, count = nic->params.rfds.count;
 
+	nic->ru_running = RU_UNINITIALIZED;
+
 	if(nic->rxs) {
 		for(rx = nic->rxs, i = 0; i < count; rx++, i++) {
 			if(rx->skb) {
@@ -1883,6 +1931,7 @@ static int e100_rx_alloc_list(struct nic *nic)
 	unsigned int i, count = nic->params.rfds.count;
 
 	nic->rx_to_use = nic->rx_to_clean = NULL;
+	nic->ru_running = RU_UNINITIALIZED;
 
 	if(!(nic->rxs = kcalloc(count, sizeof(struct rx), GFP_ATOMIC)))
 		return -ENOMEM;
@@ -1897,6 +1946,7 @@ static int e100_rx_alloc_list(struct nic *nic)
 	}
 
 	nic->rx_to_use = nic->rx_to_clean = nic->rxs;
+	nic->ru_running = RU_SUSPENDED;
 
 	return 0;
 }
@@ -1916,6 +1966,10 @@ static irqreturn_t e100_intr(int irq, void *dev_id)
 	/* Ack interrupt(s) */
 	iowrite8(stat_ack, &nic->csr->scb.stat_ack);
 
+	/* We hit Receive No Resource (RNR); restart RU after cleaning */
+	if(stat_ack & stat_ack_rnr)
+		nic->ru_running = RU_SUSPENDED;
+
 	if(likely(netif_rx_schedule_prep(netdev))) {
 		e100_disable_irq(nic);
 		__netif_rx_schedule(netdev);
@@ -2007,7 +2061,7 @@ static int e100_up(struct nic *nic)
 	if((err = e100_hw_init(nic)))
 		goto err_clean_cbs;
 	e100_set_multicast_list(nic->netdev);
-	e100_start_receiver(nic);
+	e100_start_receiver(nic, NULL);
 	mod_timer(&nic->watchdog, jiffies);
 	if((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
 		nic->netdev->name, nic->netdev)))
@@ -2088,7 +2142,7 @@ static int e100_loopback_test(struct nic *nic, enum loopback loopback_mode)
 		mdio_write(nic->netdev, nic->mii.phy_id, MII_BMCR,
 			BMCR_LOOPBACK);
 
-	e100_start_receiver(nic);
+	e100_start_receiver(nic, NULL);
 
 	if(!(skb = netdev_alloc_skb(nic->netdev, ETH_DATA_LEN))) {
 		err = -ENOMEM;