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From:   <stefanc@marvell.com>
To:     <netdev@vger.kernel.org>
CC:     <thomas.petazzoni@bootlin.com>, <davem@davemloft.net>,
        <nadavh@marvell.com>, <ymarkman@marvell.com>,
        <linux-kernel@vger.kernel.org>, <stefanc@marvell.com>,
        <kuba@kernel.org>, <linux@armlinux.org.uk>, <mw@semihalf.com>,
        <andrew@lunn.ch>, <rmk+kernel@armlinux.org.uk>,
        <atenart@kernel.org>
Subject: [PATCH v8 net-next 07/15] net: mvpp2: add FCA periodic timer configurations
Date:   Sat, 6 Feb 2021 18:45:53 +0200
Message-ID: <1612629961-11583-8-git-send-email-stefanc@marvell.com>
In-Reply-To: <1612629961-11583-1-git-send-email-stefanc@marvell.com>
References: <1612629961-11583-1-git-send-email-stefanc@marvell.com>
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From: Stefan Chulski <stefanc@marvell.com>

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

Signed-off-by: Stefan Chulski <stefanc@marvell.com>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2.h      | 13 +++++-
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 45 ++++++++++++++++++++
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
index cac9885..73f087c 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
+++ b/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
@@ -752,7 +761,9 @@
 		((kb) * 1024 - MVPP2_TX_FIFO_THRESHOLD_MIN)
 
 /* MSS Flow control */
-#define MSS_SRAM_SIZE	0x800
+#define MSS_SRAM_SIZE		0x800
+#define FC_QUANTA		0xFFFF
+#define FC_CLK_DIVIDER		100
 
 /* 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 d80947a..6e59d07 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -1281,6 +1281,49 @@ 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;
@@ -1325,6 +1368,8 @@ 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;
 
-- 
1.9.1