Revert "mvebu: remove linux 4.4 support"

This reverts commit 51397d7d95d9f5e210a5557f65de1fa21e6f5921.
There are some unresolved random crashes on WRT1900AC v1 that still need
to be sorted out

Signed-off-by: Felix Fietkau <nbd@nbd.name>

1 files changed, 278 insertions, 0 deletions

diff --git a/target/linux/mvebu/patches-4.4/033-net-mvneta-Associate-RX-queues-with-each-CPU.patch b/target/linux/mvebu/patches-4.4/033-net-mvneta-Associate-RX-queues-with-each-CPU.patch
new file mode 100644
index 0000000000..636c6cf364
--- /dev/null
+++ b/target/linux/mvebu/patches-4.4/033-net-mvneta-Associate-RX-queues-with-each-CPU.patch
@@ -0,0 +1,278 @@
+From: Gregory CLEMENT <gregory.clement@free-electrons.com>
+Date: Wed, 9 Dec 2015 18:23:49 +0100
+Subject: [PATCH] net: mvneta: Associate RX queues with each CPU
+
+We enable the percpu interrupt for all the CPU and we just associate a
+CPU to a few queue at the neta level. The mapping between the CPUs and
+the queues is static. The queues are associated to the CPU module the
+number of CPUs. However currently we only use on RX queue for a given
+Ethernet port.
+
+Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+
+--- a/drivers/net/ethernet/marvell/mvneta.c
++++ b/drivers/net/ethernet/marvell/mvneta.c
+@@ -110,9 +110,16 @@
+ #define MVNETA_CPU_MAP(cpu)                      (0x2540 + ((cpu) << 2))
+ #define      MVNETA_CPU_RXQ_ACCESS_ALL_MASK      0x000000ff
+ #define      MVNETA_CPU_TXQ_ACCESS_ALL_MASK      0x0000ff00
++#define      MVNETA_CPU_RXQ_ACCESS(rxq)		 BIT(rxq)
+ #define MVNETA_RXQ_TIME_COAL_REG(q)              (0x2580 + ((q) << 2))
+ 
+-/* Exception Interrupt Port/Queue Cause register */
++/* Exception Interrupt Port/Queue Cause register
++ *
++ * Their behavior depend of the mapping done using the PCPX2Q
++ * registers. For a given CPU if the bit associated to a queue is not
++ * set, then for the register a read from this CPU will always return
++ * 0 and a write won't do anything
++ */
+ 
+ #define MVNETA_INTR_NEW_CAUSE                    0x25a0
+ #define MVNETA_INTR_NEW_MASK                     0x25a4
+@@ -820,7 +827,13 @@ static void mvneta_port_up(struct mvneta
+ 	mvreg_write(pp, MVNETA_TXQ_CMD, q_map);
+ 
+ 	/* Enable all initialized RXQs. */
+-	mvreg_write(pp, MVNETA_RXQ_CMD, BIT(pp->rxq_def));
++	for (queue = 0; queue < rxq_number; queue++) {
++		struct mvneta_rx_queue *rxq = &pp->rxqs[queue];
++
++		if (rxq->descs != NULL)
++			q_map |= (1 << queue);
++	}
++	mvreg_write(pp, MVNETA_RXQ_CMD, q_map);
+ }
+ 
+ /* Stop the Ethernet port activity */
+@@ -1026,6 +1039,7 @@ static void mvneta_defaults_set(struct m
+ 	int cpu;
+ 	int queue;
+ 	u32 val;
++	int max_cpu = num_present_cpus();
+ 
+ 	/* Clear all Cause registers */
+ 	mvreg_write(pp, MVNETA_INTR_NEW_CAUSE, 0);
+@@ -1041,13 +1055,23 @@ static void mvneta_defaults_set(struct m
+ 	/* Enable MBUS Retry bit16 */
+ 	mvreg_write(pp, MVNETA_MBUS_RETRY, 0x20);
+ 
+-	/* Set CPU queue access map - all CPUs have access to all RX
+-	 * queues and to all TX queues
++	/* Set CPU queue access map. CPUs are assigned to the RX
++	 * queues modulo their number and all the TX queues are
++	 * assigned to the CPU associated to the default RX queue.
+ 	 */
+-	for_each_present_cpu(cpu)
+-		mvreg_write(pp, MVNETA_CPU_MAP(cpu),
+-			    (MVNETA_CPU_RXQ_ACCESS_ALL_MASK |
+-			     MVNETA_CPU_TXQ_ACCESS_ALL_MASK));
++	for_each_present_cpu(cpu) {
++		int rxq_map = 0, txq_map = 0;
++		int rxq;
++
++		for (rxq = 0; rxq < rxq_number; rxq++)
++			if ((rxq % max_cpu) == cpu)
++				rxq_map |= MVNETA_CPU_RXQ_ACCESS(rxq);
++
++		if (cpu == rxq_def)
++			txq_map = MVNETA_CPU_TXQ_ACCESS_ALL_MASK;
++
++		mvreg_write(pp, MVNETA_CPU_MAP(cpu), rxq_map | txq_map);
++	}
+ 
+ 	/* Reset RX and TX DMAs */
+ 	mvreg_write(pp, MVNETA_PORT_RX_RESET, MVNETA_PORT_RX_DMA_RESET);
+@@ -2174,6 +2198,7 @@ static int mvneta_poll(struct napi_struc
+ {
+ 	int rx_done = 0;
+ 	u32 cause_rx_tx;
++	int rx_queue;
+ 	struct mvneta_port *pp = netdev_priv(napi->dev);
+ 	struct mvneta_pcpu_port *port = this_cpu_ptr(pp->ports);
+ 
+@@ -2205,8 +2230,15 @@ static int mvneta_poll(struct napi_struc
+ 	/* For the case where the last mvneta_poll did not process all
+ 	 * RX packets
+ 	 */
++	rx_queue = fls(((cause_rx_tx >> 8) & 0xff));
++
+ 	cause_rx_tx |= port->cause_rx_tx;
+-	rx_done = mvneta_rx(pp, budget, &pp->rxqs[pp->rxq_def]);
++
++	if (rx_queue) {
++		rx_queue = rx_queue - 1;
++		rx_done = mvneta_rx(pp, budget, &pp->rxqs[rx_queue]);
++	}
++
+ 	budget -= rx_done;
+ 
+ 	if (budget > 0) {
+@@ -2419,19 +2451,27 @@ static void mvneta_cleanup_txqs(struct m
+ /* Cleanup all Rx queues */
+ static void mvneta_cleanup_rxqs(struct mvneta_port *pp)
+ {
+-	mvneta_rxq_deinit(pp, &pp->rxqs[pp->rxq_def]);
++	int queue;
++
++	for (queue = 0; queue < txq_number; queue++)
++		mvneta_rxq_deinit(pp, &pp->rxqs[queue]);
+ }
+ 
+ 
+ /* Init all Rx queues */
+ static int mvneta_setup_rxqs(struct mvneta_port *pp)
+ {
+-	int err = mvneta_rxq_init(pp, &pp->rxqs[pp->rxq_def]);
+-	if (err) {
+-		netdev_err(pp->dev, "%s: can't create rxq=%d\n",
+-			   __func__, pp->rxq_def);
+-		mvneta_cleanup_rxqs(pp);
+-		return err;
++	int queue;
++
++	for (queue = 0; queue < rxq_number; queue++) {
++		int err = mvneta_rxq_init(pp, &pp->rxqs[queue]);
++
++		if (err) {
++			netdev_err(pp->dev, "%s: can't create rxq=%d\n",
++				   __func__, queue);
++			mvneta_cleanup_rxqs(pp);
++			return err;
++		}
+ 	}
+ 
+ 	return 0;
+@@ -2455,6 +2495,19 @@ static int mvneta_setup_txqs(struct mvne
+ 	return 0;
+ }
+ 
++static void mvneta_percpu_unmask_interrupt(void *arg)
++{
++	struct mvneta_port *pp = arg;
++
++	/* All the queue are unmasked, but actually only the ones
++	 * maped to this CPU will be unmasked
++	 */
++	mvreg_write(pp, MVNETA_INTR_NEW_MASK,
++		    MVNETA_RX_INTR_MASK_ALL |
++		    MVNETA_TX_INTR_MASK_ALL |
++		    MVNETA_MISCINTR_INTR_MASK);
++}
++
+ static void mvneta_start_dev(struct mvneta_port *pp)
+ {
+ 	unsigned int cpu;
+@@ -2472,11 +2525,10 @@ static void mvneta_start_dev(struct mvne
+ 		napi_enable(&port->napi);
+ 	}
+ 
+-	/* Unmask interrupts */
+-	mvreg_write(pp, MVNETA_INTR_NEW_MASK,
+-		    MVNETA_RX_INTR_MASK(rxq_number) |
+-		    MVNETA_TX_INTR_MASK(txq_number) |
+-		    MVNETA_MISCINTR_INTR_MASK);
++	/* Unmask interrupts. It has to be done from each CPU */
++	for_each_online_cpu(cpu)
++		smp_call_function_single(cpu, mvneta_percpu_unmask_interrupt,
++					 pp, true);
+ 	mvreg_write(pp, MVNETA_INTR_MISC_MASK,
+ 		    MVNETA_CAUSE_PHY_STATUS_CHANGE |
+ 		    MVNETA_CAUSE_LINK_CHANGE |
+@@ -2752,22 +2804,35 @@ static void mvneta_percpu_disable(void *
+ 
+ static void mvneta_percpu_elect(struct mvneta_port *pp)
+ {
+-	int online_cpu_idx, cpu, i = 0;
++	int online_cpu_idx, max_cpu, cpu, i = 0;
+ 
+ 	online_cpu_idx = pp->rxq_def % num_online_cpus();
++	max_cpu = num_present_cpus();
+ 
+ 	for_each_online_cpu(cpu) {
+-		if (i == online_cpu_idx)
+-			/* Enable per-CPU interrupt on the one CPU we
+-			 * just elected
++		int rxq_map = 0, txq_map = 0;
++		int rxq;
++
++		for (rxq = 0; rxq < rxq_number; rxq++)
++			if ((rxq % max_cpu) == cpu)
++				rxq_map |= MVNETA_CPU_RXQ_ACCESS(rxq);
++
++		if (i == online_cpu_idx) {
++			/* Map the default receive queue and transmit
++			 * queue to the elected CPU
+ 			 */
+-			smp_call_function_single(cpu, mvneta_percpu_enable,
+-						pp, true);
+-		else
+-			/* Disable per-CPU interrupt on all the other CPU */
+-			smp_call_function_single(cpu, mvneta_percpu_disable,
+-						pp, true);
++			rxq_map |= MVNETA_CPU_RXQ_ACCESS(pp->rxq_def);
++			txq_map = MVNETA_CPU_TXQ_ACCESS_ALL_MASK;
++		}
++		mvreg_write(pp, MVNETA_CPU_MAP(cpu), rxq_map | txq_map);
++
++		/* Update the interrupt mask on each CPU according the
++		 * new mapping
++		 */
++		smp_call_function_single(cpu, mvneta_percpu_unmask_interrupt,
++					 pp, true);
+ 		i++;
++
+ 	}
+ };
+ 
+@@ -2802,12 +2867,22 @@ static int mvneta_percpu_notifier(struct
+ 		mvreg_write(pp, MVNETA_INTR_MISC_MASK, 0);
+ 		napi_enable(&port->napi);
+ 
++
++		/* Enable per-CPU interrupts on the CPU that is
++		 * brought up.
++		 */
++		smp_call_function_single(cpu, mvneta_percpu_enable,
++					 pp, true);
++
+ 		/* Enable per-CPU interrupt on the one CPU we care
+ 		 * about.
+ 		 */
+ 		mvneta_percpu_elect(pp);
+ 
+-		/* Unmask all ethernet port interrupts */
++		/* Unmask all ethernet port interrupts, as this
++		 * notifier is called for each CPU then the CPU to
++		 * Queue mapping is applied
++		 */
+ 		mvreg_write(pp, MVNETA_INTR_NEW_MASK,
+ 			MVNETA_RX_INTR_MASK(rxq_number) |
+ 			MVNETA_TX_INTR_MASK(txq_number) |
+@@ -2858,7 +2933,7 @@ static int mvneta_percpu_notifier(struct
+ static int mvneta_open(struct net_device *dev)
+ {
+ 	struct mvneta_port *pp = netdev_priv(dev);
+-	int ret;
++	int ret, cpu;
+ 
+ 	pp->pkt_size = MVNETA_RX_PKT_SIZE(pp->dev->mtu);
+ 	pp->frag_size = SKB_DATA_ALIGN(MVNETA_RX_BUF_SIZE(pp->pkt_size)) +
+@@ -2888,8 +2963,13 @@ static int mvneta_open(struct net_device
+ 	 */
+ 	mvneta_percpu_disable(pp);
+ 
+-	/* Elect a CPU to handle our RX queue interrupt */
+-	mvneta_percpu_elect(pp);
++	/* Enable per-CPU interrupt on all the CPU to handle our RX
++	 * queue interrupts
++	 */
++	for_each_online_cpu(cpu)
++		smp_call_function_single(cpu, mvneta_percpu_enable,
++					 pp, true);
++
+ 
+ 	/* Register a CPU notifier to handle the case where our CPU
+ 	 * might be taken offline.