net: mvpp2: add FCA periodic timer configurations

Flow Control periodic timer would be used if port in
XOFF to transmit periodic XOFF frames.

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

@@ -596,6 +596,15 @@
 #define     MVPP22_MPCS_CLK_RESET_DIV_RATIO(n)	((n) << 4)
 #define     MVPP22_MPCS_CLK_RESET_DIV_SET	BIT(11)
 
+/* FCA registers. PPv2.2 and PPv2.3 */
+#define MVPP22_FCA_BASE(port)			(0x7600 + (port) * 0x1000)
+#define MVPP22_FCA_REG_SIZE			16
+#define MVPP22_FCA_REG_MASK			0xFFFF
+#define MVPP22_FCA_CONTROL_REG			0x0
+#define MVPP22_FCA_ENABLE_PERIODIC		BIT(11)
+#define MVPP22_PERIODIC_COUNTER_LSB_REG		(0x110)
+#define MVPP22_PERIODIC_COUNTER_MSB_REG		(0x114)
+
 /* XPCS registers. PPv2.2 and PPv2.3 */
 #define MVPP22_XPCS_BASE(port)			(0x7400 + (port) * 0x1000)
 #define MVPP22_XPCS_CFG0			0x0
@@ -751,6 +760,10 @@
 #define MVPP2_TX_FIFO_THRESHOLD(kb)	\
 		((kb) * 1024 - MVPP2_TX_FIFO_THRESHOLD_MIN)
 
+/* MSS Flow control */
+#define FC_QUANTA		0xFFFF
+#define FC_CLK_DIVIDER		100
+
 /* RX buffer constants */
 #define MVPP2_SKB_SHINFO_SIZE \
 	SKB_DATA_ALIGN(sizeof(struct skb_shared_info))

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

@@ -1280,6 +1280,49 @@ static void mvpp22_gop_init_10gkr(struct mvpp2_port *port)
 	writel(val, mpcs + MVPP22_MPCS_CLK_RESET);
 }
 
+static void mvpp22_gop_fca_enable_periodic(struct mvpp2_port *port, bool en)
+{
+	struct mvpp2 *priv = port->priv;
+	void __iomem *fca = priv->iface_base + MVPP22_FCA_BASE(port->gop_id);
+	u32 val;
+
+	val = readl(fca + MVPP22_FCA_CONTROL_REG);
+	val &= ~MVPP22_FCA_ENABLE_PERIODIC;
+	if (en)
+		val |= MVPP22_FCA_ENABLE_PERIODIC;
+	writel(val, fca + MVPP22_FCA_CONTROL_REG);
+}
+
+static void mvpp22_gop_fca_set_timer(struct mvpp2_port *port, u32 timer)
+{
+	struct mvpp2 *priv = port->priv;
+	void __iomem *fca = priv->iface_base + MVPP22_FCA_BASE(port->gop_id);
+	u32 lsb, msb;
+
+	lsb = timer & MVPP22_FCA_REG_MASK;
+	msb = timer >> MVPP22_FCA_REG_SIZE;
+
+	writel(lsb, fca + MVPP22_PERIODIC_COUNTER_LSB_REG);
+	writel(msb, fca + MVPP22_PERIODIC_COUNTER_MSB_REG);
+}
+
+/* Set Flow Control timer x100 faster than pause quanta to ensure that link
+ * partner won't send traffic if port is in XOFF mode.
+ */
+static void mvpp22_gop_fca_set_periodic_timer(struct mvpp2_port *port)
+{
+	u32 timer;
+
+	timer = (port->priv->tclk / (USEC_PER_SEC * FC_CLK_DIVIDER))
+		* FC_QUANTA;
+
+	mvpp22_gop_fca_enable_periodic(port, false);
+
+	mvpp22_gop_fca_set_timer(port, timer);
+
+	mvpp22_gop_fca_enable_periodic(port, true);
+}
+
 static int mvpp22_gop_init(struct mvpp2_port *port)
 {
 	struct mvpp2 *priv = port->priv;
@@ -1324,6 +1367,8 @@ static int mvpp22_gop_init(struct mvpp2_port *port)
 	val |= GENCONF_SOFT_RESET1_GOP;
 	regmap_write(priv->sysctrl_base, GENCONF_SOFT_RESET1, val);
 
+	mvpp22_gop_fca_set_periodic_timer(port);
+
 unsupported_conf:
 	return 0;