[openwrt/openwrt] ath79: force SGMII SerDes mode to MAC operation

[LEDE Commits]

blocktrron pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/fbbad9a9a629b388626b477e6cd692c160f63fb3

commit fbbad9a9a629b388626b477e6cd692c160f63fb3
Author: David Bauer <mail at david-bauer.net>
AuthorDate: Thu Apr 1 01:20:45 2021 +0200

    ath79: force SGMII SerDes mode to MAC operation
    
    The mode on the SGMII SerDes on the QCA9563 is 1000 Base-X by default.
    This only allows for 1000 Mbit/s links, however when used with an SGMII
    PHY in 100 Mbit/s link mode, the link remains dead.
    
    This strictly has nothing to do with the SerDes calibration, however it
    is done at the same point in the QCA reference U-Boot which is the
    blueprint for everything happening here. As the current state is more or
    less a hack, this should be fine.
    
    This fixes the issues outlined above on a TP-Link EAP-225 Outdoor.
    
    Reported-by: Tom Herbers <freifunk at tomherbers.de>
    Tested-by: Tom Herbers <freifunk at tomherbers.de>
    Signed-off-by: David Bauer <mail at david-bauer.net>
---
 .../files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c      | 5 +++++
 target/linux/ath79/patches-5.4/0040-ath79-sgmii-config.patch     | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
index abf7fc7d29..d060568593 100644
--- a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
+++ b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
@@ -602,6 +602,11 @@ static void ag71xx_sgmii_serdes_init_qca956x(struct device_node *np)
 		goto err_iomap;
 	}
 
+	t = __raw_readl(gmac_base + QCA956X_GMAC_REG_SGMII_CONFIG);
+	t &= ~(QCA956X_SGMII_CONFIG_MODE_CTRL_MASK << QCA956X_SGMII_CONFIG_MODE_CTRL_SHIFT);
+	t |= QCA956X_SGMII_CONFIG_MODE_CTRL_SGMII_MAC;
+	__raw_writel(t, gmac_base + QCA956X_GMAC_REG_SGMII_CONFIG);
+
 	pr_debug("%pOF: fixup SERDES calibration to value %i\n",
 		np_dev, serdes_cal);
 	t = __raw_readl(gmac_base + QCA956X_GMAC_REG_SGMII_SERDES);
diff --git a/target/linux/ath79/patches-5.4/0040-ath79-sgmii-config.patch b/target/linux/ath79/patches-5.4/0040-ath79-sgmii-config.patch
new file mode 100644
index 0000000000..bf7cbf2716
--- /dev/null
+++ b/target/linux/ath79/patches-5.4/0040-ath79-sgmii-config.patch
@@ -0,0 +1,9 @@
+--- a/arch/mips/include/asm/mach-ath79/ar71xx_regs.h
++++ b/arch/mips/include/asm/mach-ath79/ar71xx_regs.h
+@@ -1376,5 +1376,6 @@
+ 
+ #define QCA956X_SGMII_CONFIG_MODE_CTRL_SHIFT	0
+ #define QCA956X_SGMII_CONFIG_MODE_CTRL_MASK	0x7
++#define QCA956X_SGMII_CONFIG_MODE_CTRL_SGMII_MAC	0x2
+ 
+ #endif /* __ASM_MACH_AR71XX_REGS_H */