kernel: add at803x workaround for sgmii mode (#950)

Some (possibly broken) bootloaders incorrectly initialize the at8033 phy.
This breaks auto-negotation on these SGMII devices. The mode has therefore
to be set back in to a valid configuration by Linux.

Fixes #911

patches/openwrt/0081-kernel-add-at803x-fix-for-sgmii-mode.patch

@@ -0,0 +1,114 @@
+From: Felix Fietkau <nbd@openwrt.org>
+Date: Sun, 27 Nov 2016 22:49:27 +0100
+Subject: kernel: add at803x fix for sgmii mode
+
+Some (possibly broken) bootloaders incorreclty initialize at8033
+phy. This patch enables sgmii autonegotiation mode.
+
+Signed-off-by: Roman Yeryomin <roman@advem.lv>
+
+Origin: backport, https://git.lede-project.org/?p=source.git;a=commit;h=e14d2aee0ab91c43d0bb14baf84cc9b997185870
+Bug-gluon: https://github.com/freifunk-gluon/gluon/issues/911
+
+diff --git a/target/linux/ar71xx/patches-3.18/735-net-phy-at803x-fix-at8033-sgmii-mode.patch b/target/linux/ar71xx/patches-3.18/735-net-phy-at803x-fix-at8033-sgmii-mode.patch
+new file mode 100644
+index 0000000..4a8f532
+--- /dev/null
++++ b/target/linux/ar71xx/patches-3.18/735-net-phy-at803x-fix-at8033-sgmii-mode.patch
+@@ -0,0 +1,96 @@
++--- a/drivers/net/phy/at803x.c
+++++ b/drivers/net/phy/at803x.c
++@@ -36,6 +36,9 @@
++ #define AT803X_INER				0x0012
++ #define AT803X_INER_INIT			0xec00
++ #define AT803X_INSR				0x0013
+++#define AT803X_REG_CHIP_CONFIG			0x1f
+++#define AT803X_BT_BX_REG_SEL			0x8000
+++#define AT803X_SGMII_ANEG_EN			0x1000
++ 
++ #define AT803X_PCS_SMART_EEE_CTRL3			0x805D
++ #define AT803X_SMART_EEE_CTRL3_LPI_TX_DELAY_SEL_MASK	0x3
++@@ -49,9 +52,10 @@
++ #define AT803X_DEBUG_SYSTEM_MODE_CTRL		0x05
++ #define AT803X_DEBUG_RGMII_TX_CLK_DLY		BIT(8)
++ 
++-#define ATH8030_PHY_ID 0x004dd076
++-#define ATH8031_PHY_ID 0x004dd074
++-#define ATH8035_PHY_ID 0x004dd072
+++#define AT803X_PHY_ID_MASK			0xffffffef
+++#define ATH8030_PHY_ID				0x004dd076
+++#define ATH8031_PHY_ID				0x004dd074
+++#define ATH8035_PHY_ID				0x004dd072
++ 
++ MODULE_DESCRIPTION("Atheros 803x PHY driver");
++ MODULE_AUTHOR("Matus Ujhelyi");
++@@ -267,6 +271,27 @@ static int at803x_config_init(struct phy
++ {
++ 	struct at803x_platform_data *pdata;
++ 	int ret;
+++	u32 v;
+++
+++	if (phydev->drv->phy_id == ATH8031_PHY_ID &&
+++		phydev->interface == PHY_INTERFACE_MODE_SGMII)
+++	{
+++		v = phy_read(phydev, AT803X_REG_CHIP_CONFIG);
+++		/* select SGMII/fiber page */
+++		ret = phy_write(phydev, AT803X_REG_CHIP_CONFIG,
+++						v & ~AT803X_BT_BX_REG_SEL);
+++		if (ret)
+++			return ret;
+++		/* enable SGMII autonegotiation */
+++		ret = phy_write(phydev, MII_BMCR, AT803X_SGMII_ANEG_EN);
+++		if (ret)
+++			return ret;
+++		/* select copper page */
+++		ret = phy_write(phydev, AT803X_REG_CHIP_CONFIG,
+++						v | AT803X_BT_BX_REG_SEL);
+++		if (ret)
+++			return ret;
+++	}
++ 
++ 	ret = genphy_config_init(phydev);
++ 	if (ret < 0)
++@@ -393,7 +418,7 @@ static struct phy_driver at803x_driver[]
++ 	/* ATHEROS 8035 */
++ 	.phy_id			= ATH8035_PHY_ID,
++ 	.name			= "Atheros 8035 ethernet",
++-	.phy_id_mask		= 0xffffffef,
+++	.phy_id_mask		= AT803X_PHY_ID_MASK,
++ 	.probe			= at803x_probe,
++ 	.config_init		= at803x_config_init,
++ 	.link_change_notify	= at803x_link_change_notify,
++@@ -412,7 +437,7 @@ static struct phy_driver at803x_driver[]
++ 	/* ATHEROS 8030 */
++ 	.phy_id			= ATH8030_PHY_ID,
++ 	.name			= "Atheros 8030 ethernet",
++-	.phy_id_mask		= 0xffffffef,
+++	.phy_id_mask		= AT803X_PHY_ID_MASK,
++ 	.probe			= at803x_probe,
++ 	.config_init		= at803x_config_init,
++ 	.link_change_notify	= at803x_link_change_notify,
++@@ -430,8 +455,8 @@ static struct phy_driver at803x_driver[]
++ }, {
++ 	/* ATHEROS 8031 */
++ 	.phy_id			= ATH8031_PHY_ID,
++-	.name			= "Atheros 8031 ethernet",
++-	.phy_id_mask		= 0xffffffef,
+++	.name			= "Atheros 8031/8033 ethernet",
+++	.phy_id_mask		= AT803X_PHY_ID_MASK,
++ 	.probe			= at803x_probe,
++ 	.config_init		= at803x_config_init,
++ 	.link_change_notify	= at803x_link_change_notify,
++@@ -465,9 +490,9 @@ module_init(atheros_init);
++ module_exit(atheros_exit);
++ 
++ static struct mdio_device_id __maybe_unused atheros_tbl[] = {
++-	{ ATH8030_PHY_ID, 0xffffffef },
++-	{ ATH8031_PHY_ID, 0xffffffef },
++-	{ ATH8035_PHY_ID, 0xffffffef },
+++	{ ATH8030_PHY_ID, AT803X_PHY_ID_MASK },
+++	{ ATH8031_PHY_ID, AT803X_PHY_ID_MASK },
+++	{ ATH8035_PHY_ID, AT803X_PHY_ID_MASK },
++ 	{ }
++ };
++