linux-kernel - [PATCH 03/14] drivers: net: mdio: mdio-ip8064: improve busy wait delay

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Message-Id: <20210423014741.11858-4-ansuelsmth@gmail.com>
Date:   Fri, 23 Apr 2021 03:47:29 +0200
From:   Ansuel Smith <ansuelsmth@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     Ansuel Smith <ansuelsmth@...il.com>, Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 03/14] drivers: net: mdio: mdio-ip8064: improve busy wait delay

With the use of the qca8k dsa driver, some problem arised related to
port status detection. With a load on a specific port (for example a
simple speed test), the driver starts to bheave in a strange way and
garbage data is produced. To address this, enlarge the sleep delay and
address a bug for the reg offset 31 that require additional delay for
this specific reg.

Signed-off-by: Ansuel Smith <ansuelsmth@...il.com>
---
 drivers/net/mdio/mdio-ipq8064.c | 36 ++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/drivers/net/mdio/mdio-ipq8064.c b/drivers/net/mdio/mdio-ipq8064.c
index 1bd18857e1c5..5bd6d0501642 100644
--- a/drivers/net/mdio/mdio-ipq8064.c
+++ b/drivers/net/mdio/mdio-ipq8064.c
@@ -15,25 +15,26 @@
 #include <linux/mfd/syscon.h>
 
 /* MII address register definitions */
-#define MII_ADDR_REG_ADDR                       0x10
-#define MII_BUSY                                BIT(0)
-#define MII_WRITE                               BIT(1)
-#define MII_CLKRANGE_60_100M                    (0 << 2)
-#define MII_CLKRANGE_100_150M                   (1 << 2)
-#define MII_CLKRANGE_20_35M                     (2 << 2)
-#define MII_CLKRANGE_35_60M                     (3 << 2)
-#define MII_CLKRANGE_150_250M                   (4 << 2)
-#define MII_CLKRANGE_250_300M                   (5 << 2)
+#define MII_ADDR_REG_ADDR			0x10
+#define MII_BUSY				BIT(0)
+#define MII_WRITE				BIT(1)
+#define MII_CLKRANGE(x)				((x) << 2)
+#define MII_CLKRANGE_60_100M			MII_CLKRANGE(0)
+#define MII_CLKRANGE_100_150M			MII_CLKRANGE(1)
+#define MII_CLKRANGE_20_35M			MII_CLKRANGE(2)
+#define MII_CLKRANGE_35_60M			MII_CLKRANGE(3)
+#define MII_CLKRANGE_150_250M			MII_CLKRANGE(4)
+#define MII_CLKRANGE_250_300M			MII_CLKRANGE(5)
 #define MII_CLKRANGE_MASK			GENMASK(4, 2)
 #define MII_REG_SHIFT				6
 #define MII_REG_MASK				GENMASK(10, 6)
 #define MII_ADDR_SHIFT				11
 #define MII_ADDR_MASK				GENMASK(15, 11)
 
-#define MII_DATA_REG_ADDR                       0x14
+#define MII_DATA_REG_ADDR			0x14
 
-#define MII_MDIO_DELAY_USEC                     (1000)
-#define MII_MDIO_RETRY_MSEC                     (10)
+#define MII_MDIO_DELAY_USEC			(1000)
+#define MII_MDIO_RETRY_MSEC			(10)
 
 struct ipq8064_mdio {
 	struct regmap *base; /* NSS_GMAC0_BASE */
@@ -65,7 +66,7 @@ ipq8064_mdio_read(struct mii_bus *bus, int phy_addr, int reg_offset)
 		   ((reg_offset << MII_REG_SHIFT) & MII_REG_MASK);
 
 	regmap_write(priv->base, MII_ADDR_REG_ADDR, miiaddr);
-	usleep_range(8, 10);
+	usleep_range(10, 13);
 
 	err = ipq8064_mdio_wait_busy(priv);
 	if (err)
@@ -91,7 +92,14 @@ ipq8064_mdio_write(struct mii_bus *bus, int phy_addr, int reg_offset, u16 data)
 		   ((reg_offset << MII_REG_SHIFT) & MII_REG_MASK);
 
 	regmap_write(priv->base, MII_ADDR_REG_ADDR, miiaddr);
-	usleep_range(8, 10);
+
+	/* For the specific reg 31 extra time is needed or the next
+	 * read will produce grabage data.
+	 */
+	if (reg_offset == 31)
+		usleep_range(30, 43);
+	else
+		usleep_range(10, 13);
 
 	return ipq8064_mdio_wait_busy(priv);
 }
-- 
2.30.2