linux-kernel - [PATCH] net: netcp: Fixes SGMII reset on network interface shutdown

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Date:	Fri, 24 Jul 2015 15:02:29 -0400
From:	WingMan Kwok <w-kwok2@...com>
To:	<davem@...emloft.net>, <m-karicheri2@...com>,
	<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:	WingMan Kwok <w-kwok2@...com>
Subject: [PATCH] net: netcp: Fixes SGMII reset on network interface shutdown

This patch asserts SGMII RTRESET, i.e. resetting the SGMII Tx/Rx
logic,  during network interface shutdown to avoid having the
hardware wedge when shutting down with high incoming traffic rates.
This is cleared (brought out of RTRESET) when the interface is
brought back up.


Signed-off-by: WingMan Kwok <w-kwok2@...com>
---
This patch depends on the patch set 

Subject: [net-next PATCH v1 0/6] net: netcp: Bug fixes of CPSW statistics
 collection

submitted earlier.

 drivers/net/ethernet/ti/netcp.h       |    1 +
 drivers/net/ethernet/ti/netcp_ethss.c |   18 ++++++++++++++++++
 drivers/net/ethernet/ti/netcp_sgmii.c |   30 ++++++++++++++++++++++++++++--
 3 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/netcp.h b/drivers/net/ethernet/ti/netcp.h
index bbacf5c..a8a7306 100644
--- a/drivers/net/ethernet/ti/netcp.h
+++ b/drivers/net/ethernet/ti/netcp.h
@@ -223,6 +223,7 @@ void *netcp_device_find_module(struct netcp_device *netcp_device,
 
 /* SGMII functions */
 int netcp_sgmii_reset(void __iomem *sgmii_ofs, int port);
+bool netcp_sgmii_rtreset(void __iomem *sgmii_ofs, int port, bool set);
 int netcp_sgmii_get_port_link(void __iomem *sgmii_ofs, int port);
 int netcp_sgmii_config(void __iomem *sgmii_ofs, int port, u32 interface);
 
diff --git a/drivers/net/ethernet/ti/netcp_ethss.c b/drivers/net/ethernet/ti/netcp_ethss.c
index 7782120..571cf7a 100644
--- a/drivers/net/ethernet/ti/netcp_ethss.c
+++ b/drivers/net/ethernet/ti/netcp_ethss.c
@@ -2101,11 +2101,28 @@ static void gbe_port_config(struct gbe_priv *gbe_dev, struct gbe_slave *slave,
 	writel(slave->mac_control, GBE_REG_ADDR(slave, emac_regs, mac_control));
 }
 
+static void gbe_sgmii_rtreset(struct gbe_priv *priv,
+			      struct gbe_slave *slave, bool set)
+{
+	void __iomem *sgmii_port_regs;
+
+	if (SLAVE_LINK_IS_XGMII(slave))
+		return;
+
+	if ((priv->ss_version == GBE_SS_VERSION_14) && (slave->slave_num >= 2))
+		sgmii_port_regs = priv->sgmii_port34_regs;
+	else
+		sgmii_port_regs = priv->sgmii_port_regs;
+
+	netcp_sgmii_rtreset(sgmii_port_regs, slave->slave_num, set);
+}
+
 static void gbe_slave_stop(struct gbe_intf *intf)
 {
 	struct gbe_priv *gbe_dev = intf->gbe_dev;
 	struct gbe_slave *slave = intf->slave;
 
+	gbe_sgmii_rtreset(gbe_dev, slave, true);
 	gbe_port_reset(slave);
 	/* Disable forwarding */
 	cpsw_ale_control_set(gbe_dev->ale, slave->port_num,
@@ -2147,6 +2164,7 @@ static int gbe_slave_open(struct gbe_intf *gbe_intf)
 
 	gbe_sgmii_config(priv, slave);
 	gbe_port_reset(slave);
+	gbe_sgmii_rtreset(priv, slave, false);
 	gbe_port_config(priv, slave, priv->rx_packet_max);
 	gbe_set_slave_mac(slave, gbe_intf);
 	/* enable forwarding */
diff --git a/drivers/net/ethernet/ti/netcp_sgmii.c b/drivers/net/ethernet/ti/netcp_sgmii.c
index dbeb142..5d8419f 100644
--- a/drivers/net/ethernet/ti/netcp_sgmii.c
+++ b/drivers/net/ethernet/ti/netcp_sgmii.c
@@ -18,6 +18,9 @@
 
 #include "netcp.h"
 
+#define SGMII_SRESET_RESET		BIT(0)
+#define SGMII_SRESET_RTRESET		BIT(1)
+
 #define SGMII_REG_STATUS_LOCK		BIT(4)
 #define	SGMII_REG_STATUS_LINK		BIT(0)
 #define SGMII_REG_STATUS_AUTONEG	BIT(2)
@@ -51,12 +54,35 @@ static void sgmii_write_reg_bit(void __iomem *base, int reg, u32 val)
 int netcp_sgmii_reset(void __iomem *sgmii_ofs, int port)
 {
 	/* Soft reset */
-	sgmii_write_reg_bit(sgmii_ofs, SGMII_SRESET_REG(port), 0x1);
-	while (sgmii_read_reg(sgmii_ofs, SGMII_SRESET_REG(port)) != 0x0)
+	sgmii_write_reg_bit(sgmii_ofs, SGMII_SRESET_REG(port),
+			    SGMII_SRESET_RESET);
+
+	while ((sgmii_read_reg(sgmii_ofs, SGMII_SRESET_REG(port)) &
+		SGMII_SRESET_RESET) != 0x0)
 		;
+
 	return 0;
 }
 
+/* port is 0 based */
+bool netcp_sgmii_rtreset(void __iomem *sgmii_ofs, int port, bool set)
+{
+	u32 reg;
+	bool oldval;
+
+	/* Initiate a soft reset */
+	reg = sgmii_read_reg(sgmii_ofs, SGMII_SRESET_REG(port));
+	oldval = (reg & SGMII_SRESET_RTRESET) != 0x0;
+	if (set)
+		reg |= SGMII_SRESET_RTRESET;
+	else
+		reg &= ~SGMII_SRESET_RTRESET;
+	sgmii_write_reg(sgmii_ofs, SGMII_SRESET_REG(port), reg);
+	wmb();
+
+	return oldval;
+}
+
 int netcp_sgmii_get_port_link(void __iomem *sgmii_ofs, int port)
 {
 	u32 status = 0, link = 0;
-- 
1.7.9.5

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