linux-kernel - [PATCH v3 RFC net-next 10/19] net: mvpp2: add FCA RXQ non occupied descriptor threshold

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Date:   Mon, 25 Jan 2021 19:07:57 +0200
From:   <stefanc@...vell.com>
To:     <netdev@...r.kernel.org>
CC:     <thomas.petazzoni@...tlin.com>, <davem@...emloft.net>,
        <nadavh@...vell.com>, <ymarkman@...vell.com>,
        <linux-kernel@...r.kernel.org>, <stefanc@...vell.com>,
        <kuba@...nel.org>, <linux@...linux.org.uk>, <mw@...ihalf.com>,
        <andrew@...n.ch>, <rmk+kernel@...linux.org.uk>,
        <atenart@...nel.org>
Subject: [PATCH v3 RFC net-next 10/19] net: mvpp2: add FCA RXQ non occupied descriptor threshold

From: Stefan Chulski <stefanc@...vell.com>

RXQ non occupied descriptor threshold would be used by
Flow Control Firmware feature to move to the XOFF mode.
RXQ non occupied threshold would change interrupt cause
that polled by CM3 Firmware.
Actual non occupied interrupt masked and won't trigger interrupt.

Signed-off-by: Stefan Chulski <stefanc@...vell.com>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2.h      |  3 ++
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 46 +++++++++++++++++---
 2 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
index 73f087c..9d8993f 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
@@ -295,6 +295,8 @@
 #define     MVPP2_PON_CAUSE_TXP_OCCUP_DESC_ALL_MASK	0x3fc00000
 #define     MVPP2_PON_CAUSE_MISC_SUM_MASK		BIT(31)
 #define MVPP2_ISR_MISC_CAUSE_REG		0x55b0
+#define MVPP2_ISR_RX_ERR_CAUSE_REG(port)	(0x5520 + 4 * (port))
+#define	    MVPP2_ISR_RX_ERR_CAUSE_NONOCC_MASK	0x00ff
 
 /* Buffer Manager registers */
 #define MVPP2_BM_POOL_BASE_REG(pool)		(0x6000 + ((pool) * 4))
@@ -764,6 +766,7 @@
 #define MSS_SRAM_SIZE		0x800
 #define FC_QUANTA		0xFFFF
 #define FC_CLK_DIVIDER		100
+#define MSS_THRESHOLD_STOP	768
 
 /* RX buffer constants */
 #define MVPP2_SKB_SHINFO_SIZE \
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 8f40293a..a4933c4 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -1144,14 +1144,19 @@ static inline void mvpp2_qvec_interrupt_disable(struct mvpp2_queue_vector *qvec)
 static void mvpp2_interrupts_mask(void *arg)
 {
 	struct mvpp2_port *port = arg;
+	int cpu = smp_processor_id();
+	u32 thread;
 
 	/* If the thread isn't used, don't do anything */
-	if (smp_processor_id() > port->priv->nthreads)
+	if (cpu >= port->priv->nthreads)
 		return;
 
-	mvpp2_thread_write(port->priv,
-			   mvpp2_cpu_to_thread(port->priv, smp_processor_id()),
+	thread = mvpp2_cpu_to_thread(port->priv, cpu);
+
+	mvpp2_thread_write(port->priv, thread,
 			   MVPP2_ISR_RX_TX_MASK_REG(port->id), 0);
+	mvpp2_thread_write(port->priv, thread,
+			   MVPP2_ISR_RX_ERR_CAUSE_REG(port->id), 0);
 }
 
 /* Unmask the current thread's Rx/Tx interrupts.
@@ -1161,20 +1166,25 @@ static void mvpp2_interrupts_mask(void *arg)
 static void mvpp2_interrupts_unmask(void *arg)
 {
 	struct mvpp2_port *port = arg;
-	u32 val;
+	int cpu = smp_processor_id();
+	u32 val, thread;
 
 	/* If the thread isn't used, don't do anything */
-	if (smp_processor_id() > port->priv->nthreads)
+	if (cpu >= port->priv->nthreads)
 		return;
 
+	thread = mvpp2_cpu_to_thread(port->priv, cpu);
+
 	val = MVPP2_CAUSE_MISC_SUM_MASK |
 		MVPP2_CAUSE_RXQ_OCCUP_DESC_ALL_MASK(port->priv->hw_version);
 	if (port->has_tx_irqs)
 		val |= MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_MASK;
 
-	mvpp2_thread_write(port->priv,
-			   mvpp2_cpu_to_thread(port->priv, smp_processor_id()),
+	mvpp2_thread_write(port->priv, thread,
 			   MVPP2_ISR_RX_TX_MASK_REG(port->id), val);
+	mvpp2_thread_write(port->priv, thread,
+			   MVPP2_ISR_RX_ERR_CAUSE_REG(port->id),
+			   MVPP2_ISR_RX_ERR_CAUSE_NONOCC_MASK);
 }
 
 static void
@@ -1199,6 +1209,9 @@ static void mvpp2_interrupts_unmask(void *arg)
 
 		mvpp2_thread_write(port->priv, v->sw_thread_id,
 				   MVPP2_ISR_RX_TX_MASK_REG(port->id), val);
+		mvpp2_thread_write(port->priv, v->sw_thread_id,
+				   MVPP2_ISR_RX_ERR_CAUSE_REG(port->id),
+				   MVPP2_ISR_RX_ERR_CAUSE_NONOCC_MASK);
 	}
 }
 
@@ -2404,6 +2417,22 @@ static void mvpp2_txp_max_tx_size_set(struct mvpp2_port *port)
 	}
 }
 
+/* Routine set the number of non-occupied descriptors threshold that change
+ * interrupt error cause polled by FW Flow Control
+ */
+static void mvpp2_set_rxq_free_tresh(struct mvpp2_port *port,
+				     struct mvpp2_rx_queue *rxq)
+{
+	u32 val;
+
+	mvpp2_write(port->priv, MVPP2_RXQ_NUM_REG, rxq->id);
+
+	val = mvpp2_read(port->priv, MVPP2_RXQ_THRESH_REG);
+	val &= ~MVPP2_RXQ_NON_OCCUPIED_MASK;
+	val |= MSS_THRESHOLD_STOP << MVPP2_RXQ_NON_OCCUPIED_OFFSET;
+	mvpp2_write(port->priv, MVPP2_RXQ_THRESH_REG, val);
+}
+
 /* Set the number of packets that will be received before Rx interrupt
  * will be generated by HW.
  */
@@ -2659,6 +2688,9 @@ static int mvpp2_rxq_init(struct mvpp2_port *port,
 	mvpp2_rx_pkts_coal_set(port, rxq);
 	mvpp2_rx_time_coal_set(port, rxq);
 
+	/* Set the number of non occupied descriptors threshold */
+	mvpp2_set_rxq_free_tresh(port, rxq);
+
 	/* Add number of descriptors ready for receiving packets */
 	mvpp2_rxq_status_update(port, rxq->id, 0, rxq->size);
 
-- 
1.9.1