net: mvpp2: add support for TX interrupts and RX queue distribution modes

This commit adds the support for two related features:

 - Support for TX interrupts, with one interrupt for each CPU

 - Support for different RX queue distribution modes
   MVPP2_QDIST_SINGLE_MODE where a single interrupt, shared by all
   CPUs, receives the RX events, and MVPP2_QDIST_MULTI_MODE, where the
   per-CPU interrupts used for TX events are also used for RX events.

Since additional interrupts are needed, an update to the Device Tree
binding is needed. However, backward compatibility is preserved with
the old Device Tree binding, by gracefully degrading to the original
behavior, with only one RX interrupt, and TX completion being handled
by an hrtimer.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2.c

@@ -120,6 +120,9 @@
 #define MVPP2_TXQ_DESC_ADDR_REG			0x2084
 #define MVPP2_TXQ_DESC_SIZE_REG			0x2088
 #define     MVPP2_TXQ_DESC_SIZE_MASK		0x3ff0
+#define MVPP2_TXQ_THRESH_REG			0x2094
+#define	    MVPP2_TXQ_THRESH_OFFSET		16
+#define	    MVPP2_TXQ_THRESH_MASK		0x3fff
 #define MVPP2_AGGR_TXQ_UPDATE_REG		0x2090
 #define MVPP2_TXQ_INDEX_REG			0x2098
 #define MVPP2_TXQ_PREF_BUF_REG			0x209c
@@ -183,6 +186,9 @@
 #define MVPP22_AXI_CODE_DOMAIN_SYSTEM		3
 
 /* Interrupt Cause and Mask registers */
+#define MVPP2_ISR_TX_THRESHOLD_REG(port)	(0x5140 + 4 * (port))
+#define     MVPP2_MAX_ISR_TX_THRESHOLD		0xfffff0
+
 #define MVPP2_ISR_RX_THRESHOLD_REG(rxq)		(0x5200 + 4 * (rxq))
 #define     MVPP2_MAX_ISR_RX_THRESHOLD		0xfffff0
 #define MVPP21_ISR_RXQ_GROUP_REG(port)		(0x5400 + 4 * (port))
@@ -206,6 +212,7 @@
 #define MVPP2_ISR_RX_TX_CAUSE_REG(port)		(0x5480 + 4 * (port))
 #define     MVPP2_CAUSE_RXQ_OCCUP_DESC_ALL_MASK	0xffff
 #define     MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_MASK	0xff0000
+#define     MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_OFFSET	16
 #define     MVPP2_CAUSE_RX_FIFO_OVERRUN_MASK	BIT(24)
 #define     MVPP2_CAUSE_FCS_ERR_MASK		BIT(25)
 #define     MVPP2_CAUSE_TX_FIFO_UNDERRUN_MASK	BIT(26)
@@ -372,6 +379,7 @@
 /* Coalescing */
 #define MVPP2_TXDONE_COAL_PKTS_THRESH	15
 #define MVPP2_TXDONE_HRTIMER_PERIOD_NS	1000000UL
+#define MVPP2_TXDONE_COAL_USEC		1000
 #define MVPP2_RX_COAL_PKTS		32
 #define MVPP2_RX_COAL_USEC		100
 
@@ -811,6 +819,9 @@ struct mvpp2_port {
 
 	struct mvpp2_queue_vector qvecs[MVPP2_MAX_QVECS];
 	unsigned int nqvecs;
+	bool has_tx_irqs;
+
+	u32 tx_time_coal;
 };
 
 /* The mvpp2_tx_desc and mvpp2_rx_desc structures describe the
@@ -1076,6 +1087,15 @@ struct mvpp2_bm_pool {
 	u32 port_map;
 };
 
+/* Queue modes */
+#define MVPP2_QDIST_SINGLE_MODE	0
+#define MVPP2_QDIST_MULTI_MODE	1
+
+static int queue_mode = MVPP2_QDIST_SINGLE_MODE;
+
+module_param(queue_mode, int, 0444);
+MODULE_PARM_DESC(queue_mode, "Set queue_mode (single=0, multi=1)");
+
 #define MVPP2_DRIVER_NAME "mvpp2"
 #define MVPP2_DRIVER_VERSION "1.0"
 
@@ -4187,11 +4207,40 @@ static void mvpp2_interrupts_mask(void *arg)
 static void mvpp2_interrupts_unmask(void *arg)
 {
 	struct mvpp2_port *port = arg;
+	u32 val;
+
+	val = MVPP2_CAUSE_MISC_SUM_MASK |
+		MVPP2_CAUSE_RXQ_OCCUP_DESC_ALL_MASK;
+	if (port->has_tx_irqs)
+		val |= MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_MASK;
 
 	mvpp2_percpu_write(port->priv, smp_processor_id(),
-			   MVPP2_ISR_RX_TX_MASK_REG(port->id),
-			   (MVPP2_CAUSE_MISC_SUM_MASK |
-			    MVPP2_CAUSE_RXQ_OCCUP_DESC_ALL_MASK));
+			   MVPP2_ISR_RX_TX_MASK_REG(port->id), val);
+}
+
+static void
+mvpp2_shared_interrupt_mask_unmask(struct mvpp2_port *port, bool mask)
+{
+	u32 val;
+	int i;
+
+	if (port->priv->hw_version != MVPP22)
+		return;
+
+	if (mask)
+		val = 0;
+	else
+		val = MVPP2_CAUSE_RXQ_OCCUP_DESC_ALL_MASK;
+
+	for (i = 0; i < port->nqvecs; i++) {
+		struct mvpp2_queue_vector *v = port->qvecs + i;
+
+		if (v->type != MVPP2_QUEUE_VECTOR_SHARED)
+			continue;
+
+		mvpp2_percpu_write(port->priv, v->sw_thread_id,
+				   MVPP2_ISR_RX_TX_MASK_REG(port->id), val);
+	}
 }
 
 /* Port configuration routines */
@@ -4812,6 +4861,23 @@ static void mvpp2_rx_pkts_coal_set(struct mvpp2_port *port,
 	put_cpu();
 }
 
+/* For some reason in the LSP this is done on each CPU. Why ? */
+static void mvpp2_tx_pkts_coal_set(struct mvpp2_port *port,
+				   struct mvpp2_tx_queue *txq)
+{
+	int cpu = get_cpu();
+	u32 val;
+
+	if (txq->done_pkts_coal > MVPP2_TXQ_THRESH_MASK)
+		txq->done_pkts_coal = MVPP2_TXQ_THRESH_MASK;
+
+	val = (txq->done_pkts_coal << MVPP2_TXQ_THRESH_OFFSET);
+	mvpp2_percpu_write(port->priv, cpu, MVPP2_TXQ_NUM_REG, txq->id);
+	mvpp2_percpu_write(port->priv, cpu, MVPP2_TXQ_THRESH_REG, val);
+
+	put_cpu();
+}
+
 static u32 mvpp2_usec_to_cycles(u32 usec, unsigned long clk_hz)
 {
 	u64 tmp = (u64)clk_hz * usec;
@@ -4848,6 +4914,22 @@ static void mvpp2_rx_time_coal_set(struct mvpp2_port *port,
 	mvpp2_write(port->priv, MVPP2_ISR_RX_THRESHOLD_REG(rxq->id), val);
 }
 
+static void mvpp2_tx_time_coal_set(struct mvpp2_port *port)
+{
+	unsigned long freq = port->priv->tclk;
+	u32 val = mvpp2_usec_to_cycles(port->tx_time_coal, freq);
+
+	if (val > MVPP2_MAX_ISR_TX_THRESHOLD) {
+		port->tx_time_coal =
+			mvpp2_cycles_to_usec(MVPP2_MAX_ISR_TX_THRESHOLD, freq);
+
+		/* re-evaluate to get actual register value */
+		val = mvpp2_usec_to_cycles(port->tx_time_coal, freq);
+	}
+
+	mvpp2_write(port->priv, MVPP2_ISR_TX_THRESHOLD_REG(port->id), val);
+}
+
 /* Free Tx queue skbuffs */
 static void mvpp2_txq_bufs_free(struct mvpp2_port *port,
 				struct mvpp2_tx_queue *txq,
@@ -4906,7 +4988,8 @@ static void mvpp2_txq_done(struct mvpp2_port *port, struct mvpp2_tx_queue *txq,
 			netif_tx_wake_queue(nq);
 }
 
-static unsigned int mvpp2_tx_done(struct mvpp2_port *port, u32 cause)
+static unsigned int mvpp2_tx_done(struct mvpp2_port *port, u32 cause,
+				  int cpu)
 {
 	struct mvpp2_tx_queue *txq;
 	struct mvpp2_txq_pcpu *txq_pcpu;
@@ -4917,7 +5000,7 @@ static unsigned int mvpp2_tx_done(struct mvpp2_port *port, u32 cause)
 		if (!txq)
 			break;
 
-		txq_pcpu = this_cpu_ptr(txq->pcpu);
+		txq_pcpu = per_cpu_ptr(txq->pcpu, cpu);
 
 		if (txq_pcpu->count) {
 			mvpp2_txq_done(port, txq, txq_pcpu);
@@ -5305,6 +5388,14 @@ static int mvpp2_setup_txqs(struct mvpp2_port *port)
 			goto err_cleanup;
 	}
 
+	if (port->has_tx_irqs) {
+		mvpp2_tx_time_coal_set(port);
+		for (queue = 0; queue < port->ntxqs; queue++) {
+			txq = port->txqs[queue];
+			mvpp2_tx_pkts_coal_set(port, txq);
+		}
+	}
+
 	on_each_cpu(mvpp2_txq_sent_counter_clear, port, 1);
 	return 0;
 
@@ -5411,7 +5502,7 @@ static void mvpp2_tx_proc_cb(unsigned long data)
 
 	/* Process all the Tx queues */
 	cause = (1 << port->ntxqs) - 1;
-	tx_todo = mvpp2_tx_done(port, cause);
+	tx_todo = mvpp2_tx_done(port, cause, smp_processor_id());
 
 	/* Set the timer in case not all the packets were processed */
 	if (tx_todo)
@@ -5787,7 +5878,8 @@ static int mvpp2_tx(struct sk_buff *skb, struct net_device *dev)
 		mvpp2_txq_done(port, txq, txq_pcpu);
 
 	/* Set the timer in case not all frags were processed */
-	if (txq_pcpu->count <= frags && txq_pcpu->count > 0) {
+	if (!port->has_tx_irqs && txq_pcpu->count <= frags &&
+	    txq_pcpu->count > 0) {
 		struct mvpp2_port_pcpu *port_pcpu = this_cpu_ptr(port->pcpu);
 
 		mvpp2_timer_set(port_pcpu);
@@ -5808,7 +5900,7 @@ static inline void mvpp2_cause_error(struct net_device *dev, int cause)
 
 static int mvpp2_poll(struct napi_struct *napi, int budget)
 {
-	u32 cause_rx_tx, cause_rx, cause_misc;
+	u32 cause_rx_tx, cause_rx, cause_tx, cause_misc;
 	int rx_done = 0;
 	struct mvpp2_port *port = netdev_priv(napi->dev);
 	struct mvpp2_queue_vector *qv;
@@ -5826,11 +5918,10 @@ static int mvpp2_poll(struct napi_struct *napi, int budget)
 	 *
 	 * Each CPU has its own Rx/Tx cause register
 	 */
-	cause_rx_tx = mvpp2_percpu_read(port->priv, cpu,
+	cause_rx_tx = mvpp2_percpu_read(port->priv, qv->sw_thread_id,
 					MVPP2_ISR_RX_TX_CAUSE_REG(port->id));
-	cause_rx_tx &= ~MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_MASK;
-	cause_misc = cause_rx_tx & MVPP2_CAUSE_MISC_SUM_MASK;
 
+	cause_misc = cause_rx_tx & MVPP2_CAUSE_MISC_SUM_MASK;
 	if (cause_misc) {
 		mvpp2_cause_error(port->dev, cause_misc);
 
@@ -5841,9 +5932,15 @@ static int mvpp2_poll(struct napi_struct *napi, int budget)
 				   cause_rx_tx & ~MVPP2_CAUSE_MISC_SUM_MASK);
 	}
 
-	cause_rx = cause_rx_tx & MVPP2_CAUSE_RXQ_OCCUP_DESC_ALL_MASK;
+	cause_tx = cause_rx_tx & MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_MASK;
+	if (cause_tx) {
+		cause_tx >>= MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_OFFSET;
+		mvpp2_tx_done(port, cause_tx, qv->sw_thread_id);
+	}
 
 	/* Process RX packets */
+	cause_rx = cause_rx_tx & MVPP2_CAUSE_RXQ_OCCUP_DESC_ALL_MASK;
+	cause_rx <<= qv->first_rxq;
 	cause_rx |= qv->pending_cause_rx;
 	while (cause_rx && budget > 0) {
 		int count;
@@ -6006,6 +6103,10 @@ static int mvpp2_irqs_init(struct mvpp2_port *port)
 		err = request_irq(qv->irq, mvpp2_isr, 0, port->dev->name, qv);
 		if (err)
 			goto err;
+
+		if (qv->type == MVPP2_QUEUE_VECTOR_PRIVATE)
+			irq_set_affinity_hint(qv->irq,
+					      cpumask_of(qv->sw_thread_id));
 	}
 
 	return 0;
@@ -6013,6 +6114,7 @@ static int mvpp2_irqs_init(struct mvpp2_port *port)
 	for (i = 0; i < port->nqvecs; i++) {
 		struct mvpp2_queue_vector *qv = port->qvecs + i;
 
+		irq_set_affinity_hint(qv->irq, NULL);
 		free_irq(qv->irq, qv);
 	}
 
@@ -6026,6 +6128,7 @@ static void mvpp2_irqs_deinit(struct mvpp2_port *port)
 	for (i = 0; i < port->nqvecs; i++) {
 		struct mvpp2_queue_vector *qv = port->qvecs + i;
 
+		irq_set_affinity_hint(qv->irq, NULL);
 		free_irq(qv->irq, qv);
 	}
 }
@@ -6087,6 +6190,7 @@ static int mvpp2_open(struct net_device *dev)
 
 	/* Unmask interrupts on all CPUs */
 	on_each_cpu(mvpp2_interrupts_unmask, port, 1);
+	mvpp2_shared_interrupt_mask_unmask(port, false);
 
 	mvpp2_start_dev(port);
 
@@ -6112,8 +6216,10 @@ static int mvpp2_stop(struct net_device *dev)
 
 	/* Mask interrupts on all CPUs */
 	on_each_cpu(mvpp2_interrupts_mask, port, 1);
+	mvpp2_shared_interrupt_mask_unmask(port, true);
 
 	mvpp2_irqs_deinit(port);
+	if (!port->has_tx_irqs) {
 		for_each_present_cpu(cpu) {
 			port_pcpu = per_cpu_ptr(port->pcpu, cpu);
 
@@ -6121,6 +6227,7 @@ static int mvpp2_stop(struct net_device *dev)
 			port_pcpu->timer_scheduled = false;
 			tasklet_kill(&port_pcpu->tx_done_tasklet);
 		}
+	}
 	mvpp2_cleanup_rxqs(port);
 	mvpp2_cleanup_txqs(port);
 
@@ -6303,10 +6410,18 @@ static int mvpp2_ethtool_set_coalesce(struct net_device *dev,
 		mvpp2_rx_time_coal_set(port, rxq);
 	}
 
+	if (port->has_tx_irqs) {
+		port->tx_time_coal = c->tx_coalesce_usecs;
+		mvpp2_tx_time_coal_set(port);
+	}
+
 	for (queue = 0; queue < port->ntxqs; queue++) {
 		struct mvpp2_tx_queue *txq = port->txqs[queue];
 
 		txq->done_pkts_coal = c->tx_max_coalesced_frames;
+
+		if (port->has_tx_irqs)
+			mvpp2_tx_pkts_coal_set(port, txq);
 	}
 
 	return 0;
@@ -6431,7 +6546,10 @@ static const struct ethtool_ops mvpp2_eth_tool_ops = {
 	.set_link_ksettings = phy_ethtool_set_link_ksettings,
 };
 
-static int mvpp2_queue_vectors_init(struct mvpp2_port *port,
+/* Used for PPv2.1, or PPv2.2 with the old Device Tree binding that
+ * had a single IRQ defined per-port.
+ */
+static int mvpp2_simple_queue_vectors_init(struct mvpp2_port *port,
 					   struct device_node *port_node)
 {
 	struct mvpp2_queue_vector *v = &port->qvecs[0];
@@ -6453,6 +6571,66 @@ static int mvpp2_queue_vectors_init(struct mvpp2_port *port,
 	return 0;
 }
 
+static int mvpp2_multi_queue_vectors_init(struct mvpp2_port *port,
+					  struct device_node *port_node)
+{
+	struct mvpp2_queue_vector *v;
+	int i, ret;
+
+	port->nqvecs = num_possible_cpus();
+	if (queue_mode == MVPP2_QDIST_SINGLE_MODE)
+		port->nqvecs += 1;
+
+	for (i = 0; i < port->nqvecs; i++) {
+		char irqname[16];
+
+		v = port->qvecs + i;
+
+		v->port = port;
+		v->type = MVPP2_QUEUE_VECTOR_PRIVATE;
+		v->sw_thread_id = i;
+		v->sw_thread_mask = BIT(i);
+
+		snprintf(irqname, sizeof(irqname), "tx-cpu%d", i);
+
+		if (queue_mode == MVPP2_QDIST_MULTI_MODE) {
+			v->first_rxq = i * MVPP2_DEFAULT_RXQ;
+			v->nrxqs = MVPP2_DEFAULT_RXQ;
+		} else if (queue_mode == MVPP2_QDIST_SINGLE_MODE &&
+			   i == (port->nqvecs - 1)) {
+			v->first_rxq = 0;
+			v->nrxqs = port->nrxqs;
+			v->type = MVPP2_QUEUE_VECTOR_SHARED;
+			strncpy(irqname, "rx-shared", sizeof(irqname));
+		}
+
+		v->irq = of_irq_get_byname(port_node, irqname);
+		if (v->irq <= 0) {
+			ret = -EINVAL;
+			goto err;
+		}
+
+		netif_napi_add(port->dev, &v->napi, mvpp2_poll,
+			       NAPI_POLL_WEIGHT);
+	}
+
+	return 0;
+
+err:
+	for (i = 0; i < port->nqvecs; i++)
+		irq_dispose_mapping(port->qvecs[i].irq);
+	return ret;
+}
+
+static int mvpp2_queue_vectors_init(struct mvpp2_port *port,
+				    struct device_node *port_node)
+{
+	if (port->has_tx_irqs)
+		return mvpp2_multi_queue_vectors_init(port, port_node);
+	else
+		return mvpp2_simple_queue_vectors_init(port, port_node);
+}
+
 static void mvpp2_queue_vectors_deinit(struct mvpp2_port *port)
 {
 	int i;
@@ -6512,6 +6690,8 @@ static int mvpp2_port_init(struct mvpp2_port *port)
 	mvpp2_egress_disable(port);
 	mvpp2_port_disable(port);
 
+	port->tx_time_coal = MVPP2_TXDONE_COAL_USEC;
+
 	port->txqs = devm_kcalloc(dev, port->ntxqs, sizeof(*port->txqs),
 				  GFP_KERNEL);
 	if (!port->txqs)
@@ -6611,6 +6791,30 @@ static int mvpp2_port_init(struct mvpp2_port *port)
 	return err;
 }
 
+/* Checks if the port DT description has the TX interrupts
+ * described. On PPv2.1, there are no such interrupts. On PPv2.2,
+ * there are available, but we need to keep support for old DTs.
+ */
+static bool mvpp2_port_has_tx_irqs(struct mvpp2 *priv,
+				   struct device_node *port_node)
+{
+	char *irqs[5] = { "rx-shared", "tx-cpu0", "tx-cpu1",
+			  "tx-cpu2", "tx-cpu3" };
+	int ret, i;
+
+	if (priv->hw_version == MVPP21)
+		return false;
+
+	for (i = 0; i < 5; i++) {
+		ret = of_property_match_string(port_node, "interrupt-names",
+					       irqs[i]);
+		if (ret < 0)
+			return false;
+	}
+
+	return true;
+}
+
 /* Ports initialization */
 static int mvpp2_port_probe(struct platform_device *pdev,
 			    struct device_node *port_node,
@@ -6625,12 +6829,21 @@ static int mvpp2_port_probe(struct platform_device *pdev,
 	const char *mac_from;
 	char hw_mac_addr[ETH_ALEN];
 	unsigned int ntxqs, nrxqs;
+	bool has_tx_irqs;
 	u32 id;
 	int features;
 	int phy_mode;
 	int err, i, cpu;
 
+	has_tx_irqs = mvpp2_port_has_tx_irqs(priv, port_node);
+
+	if (!has_tx_irqs)
+		queue_mode = MVPP2_QDIST_SINGLE_MODE;
+
 	ntxqs = MVPP2_MAX_TXQ;
+	if (priv->hw_version == MVPP22 && queue_mode == MVPP2_QDIST_MULTI_MODE)
+		nrxqs = MVPP2_DEFAULT_RXQ * num_possible_cpus();
+	else
 		nrxqs = MVPP2_DEFAULT_RXQ;
 
 	dev = alloc_etherdev_mqs(sizeof(*port), ntxqs, nrxqs);
@@ -6666,6 +6879,8 @@ static int mvpp2_port_probe(struct platform_device *pdev,
 	port->dev = dev;
 	port->ntxqs = ntxqs;
 	port->nrxqs = nrxqs;
+	port->priv = priv;
+	port->has_tx_irqs = has_tx_irqs;
 
 	err = mvpp2_queue_vectors_init(port, port_node);
 	if (err)
@@ -6674,7 +6889,6 @@ static int mvpp2_port_probe(struct platform_device *pdev,
 	if (of_property_read_bool(port_node, "marvell,loopback"))
 		port->flags |= MVPP2_F_LOOPBACK;
 
-	port->priv = priv;
 	port->id = id;
 	if (priv->hw_version == MVPP21)
 		port->first_rxq = port->id * port->nrxqs;
@@ -6749,6 +6963,7 @@ static int mvpp2_port_probe(struct platform_device *pdev,
 		goto err_free_txq_pcpu;
 	}
 
+	if (!port->has_tx_irqs) {
 		for_each_present_cpu(cpu) {
 			port_pcpu = per_cpu_ptr(port->pcpu, cpu);
 
@@ -6757,9 +6972,11 @@ static int mvpp2_port_probe(struct platform_device *pdev,
 			port_pcpu->tx_done_timer.function = mvpp2_hr_timer_cb;
 			port_pcpu->timer_scheduled = false;
 
-		tasklet_init(&port_pcpu->tx_done_tasklet, mvpp2_tx_proc_cb,
+			tasklet_init(&port_pcpu->tx_done_tasklet,
+				     mvpp2_tx_proc_cb,
 				     (unsigned long)dev);
 		}
+	}
 
 	features = NETIF_F_SG | NETIF_F_IP_CSUM;
 	dev->features = features | NETIF_F_RXCSUM;