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From 53c3bd0d5a873c23841bb95e7b95c1c3630c50bd Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Thu, 12 Jul 2018 13:03:13 +0300
Subject: [PATCH] at803x: Address packet drops at low traffic rate due to
SmartEEE feature
* According to the AR8035 datasheet, smartEEE mode (active by default)
makes the PHY enters sleep after a configurable idle time. It does
this autonomously, without LPI (Low Power Idle) signals coming from MAC.
* Tested with ping (default of 1 second interval) over back-to-back
RGMII between 2 boards having AR8035 at both ends:
- Without patch:
225 packets transmitted, 145 received, 35% packet loss, time 229334ms
- With patch:
144 packets transmitted, 144 received, 0% packet loss, time 146378ms
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
drivers/net/phy/Kconfig | 10 ++++++++++
drivers/net/phy/at803x.c | 22 ++++++++++++++++++++++
2 files changed, 32 insertions(+)
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -363,6 +363,16 @@ config AT803X_PHY
---help---
Currently supports the AT8030 and AT8035 model
+config AT803X_PHY_SMART_EEE
+ depends on AT803X_PHY
+ default n
+ tristate "SmartEEE feature for AT803X PHYs"
+ ---help---
+ Enables the Atheros SmartEEE feature (not IEEE 802.3az). When 2 PHYs
+ which support this feature are connected back-to-back, they may
+ negotiate a low-power sleep mode autonomously, without the Ethernet
+ controller's knowledge. May cause packet loss.
+
config BCM63XX_PHY
tristate "Broadcom 63xx SOCs internal PHY"
depends on BCM63XX || COMPILE_TEST
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -62,6 +62,8 @@
#define AT803X_DEBUG_REG_5 0x05
#define AT803X_DEBUG_TX_CLK_DLY_EN BIT(8)
+#define AT803X_LPI_EN BIT(8)
+
#define ATH8030_PHY_ID 0x004dd076
#define ATH8031_PHY_ID 0x004dd074
#define ATH8032_PHY_ID 0x004dd023
@@ -299,10 +301,30 @@ static int at803x_probe(struct phy_devic
return ret;
}
+static void at803x_enable_smart_eee(struct phy_device *phydev, int on)
+{
+ int value;
+
+ /* 5.1.11 Smart_eee control3 */
+ value = phy_read_mmd(phydev, MDIO_MMD_PCS, 0x805D);
+ if (on)
+ value |= AT803X_LPI_EN;
+ else
+ value &= ~AT803X_LPI_EN;
+ phy_write_mmd(phydev, MDIO_MMD_PCS, 0x805D, value);
+}
+
static int at803x_config_init(struct phy_device *phydev)
{
int ret;
+
+#ifdef CONFIG_AT803X_PHY_SMART_EEE
+ at803x_enable_smart_eee(phydev, 1);
+#else
+ at803x_enable_smart_eee(phydev, 0);
+#endif
+
/* The RX and TX delay default is:
* after HW reset: RX delay enabled and TX delay disabled
* after SW reset: RX delay enabled, while TX delay retains the
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