net: mvpp2: add TX FC firmware check

Patch check that TX FC firmware is running in CM3.
If not, global TX FC would be disabled.
Signed-off-by: Stefan Chulski <stefanc@marvell.com>
Acked-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2/mvpp2.h

@@ -828,6 +828,7 @@
 
 #define MSS_THRESHOLD_STOP	768
 #define MSS_THRESHOLD_START	1024
+#define MSS_FC_MAX_TIMEOUT	5000
 
 /* RX buffer constants */
 #define MVPP2_SKB_SHINFO_SIZE \

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

@@ -924,6 +924,34 @@ static void mvpp2_bm_pool_update_fc(struct mvpp2_port *port,
 	spin_unlock_irqrestore(&port->priv->mss_spinlock, flags);
 }
 
+static int mvpp2_enable_global_fc(struct mvpp2 *priv)
+{
+	int val, timeout = 0;
+
+	/* Enable global flow control. In this stage global
+	 * flow control enabled, but still disabled per port.
+	 */
+	val = mvpp2_cm3_read(priv, MSS_FC_COM_REG);
+	val |= FLOW_CONTROL_ENABLE_BIT;
+	mvpp2_cm3_write(priv, MSS_FC_COM_REG, val);
+
+	/* Check if Firmware running and disable FC if not*/
+	val |= FLOW_CONTROL_UPDATE_COMMAND_BIT;
+	mvpp2_cm3_write(priv, MSS_FC_COM_REG, val);
+
+	while (timeout < MSS_FC_MAX_TIMEOUT) {
+		val = mvpp2_cm3_read(priv, MSS_FC_COM_REG);
+
+		if (!(val & FLOW_CONTROL_UPDATE_COMMAND_BIT))
+			return 0;
+		usleep_range(10, 20);
+		timeout++;
+	}
+
+	priv->global_tx_fc = false;
+	return -EOPNOTSUPP;
+}
+
 /* Release buffer to BM */
 static inline void mvpp2_bm_pool_put(struct mvpp2_port *port, int pool,
 				     dma_addr_t buf_dma_addr,
@@ -7264,7 +7292,7 @@ static int mvpp2_probe(struct platform_device *pdev)
 	struct resource *res;
 	void __iomem *base;
 	int i, shared;
-	int err, val;
+	int err;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -7488,13 +7516,10 @@ static int mvpp2_probe(struct platform_device *pdev)
 		goto err_port_probe;
 	}
 
-	/* Enable global flow control. In this stage global
-	 * flow control enabled, but still disabled per port.
-	 */
 	if (priv->global_tx_fc && priv->hw_version != MVPP21) {
-		val = mvpp2_cm3_read(priv, MSS_FC_COM_REG);
-		val |= FLOW_CONTROL_ENABLE_BIT;
-		mvpp2_cm3_write(priv, MSS_FC_COM_REG, val);
+		err = mvpp2_enable_global_fc(priv);
+		if (err)
+			dev_warn(&pdev->dev, "Minimum of CM3 firmware 18.09 and chip revision B0 required for flow control\n");
 	}
 
 	mvpp2_dbgfs_init(priv, pdev->name);