[PATCH 1/3] ipq806x: dwmac: clear forced speed during probe

[Mark Mentovai]

On a Ubiquiti UniFi AC HD (ubnt,unifi-ac-hd, UAP-AC-HD, UAP301), a
forced speed on gmac1 is set in the QSGMII PCS_ALL_CH_CTL register,
presumably by the bootloader (4.3.28), preventing the interface from
being usable. The QSDK NSS GMAC driver takes care to clear the forced
speed in nss_gmac_qsgmii_dev_init
(https://source.codeaurora.org/quic/qsdk/oss/lklm/nss-gmac/tree/ipq806x/nss_gmac_init.c?h=nss
at d5bb14925861).

gmac1 is connected to the port on the device labeled SECONDARY, and is
currently eth0 but will be switched to eth1 by a subsequent patch. By
clearing the QSGMII PCS forced speed during dwmac initialization when
SGMII is in use, this port becomes usable.

This patch is upstreamable, and will be sent upstream after successful
testing in OpenWrt.

Signed-off-by: Mark Mentovai <mark at moxienet.com>
Build-tested: ipq806x/ubnt,unifi-ac-hd
Run-tested: ipq806x/ubnt,unifi-ac-hd
---
 ...-dwmac-ipq806x-qsgmii-pcs-all-ch-ctl.patch | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 target/linux/ipq806x/patches-5.4/100-dwmac-ipq806x-qsgmii-pcs-all-ch-ctl.patch

diff --git a/target/linux/ipq806x/patches-5.4/100-dwmac-ipq806x-qsgmii-pcs-all-ch-ctl.patch b/target/linux/ipq806x/patches-5.4/100-dwmac-ipq806x-qsgmii-pcs-all-ch-ctl.patch
new file mode 100644
index 000000000000..6cdbf4d3dc6b
--- /dev/null
+++ b/target/linux/ipq806x/patches-5.4/100-dwmac-ipq806x-qsgmii-pcs-all-ch-ctl.patch
@@ -0,0 +1,33 @@
+--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c
++++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c
+@@ -64,6 +64,17 @@
+ #define NSS_COMMON_CLK_DIV_SGMII_100		4
+ #define NSS_COMMON_CLK_DIV_SGMII_10		49
+ 
++#define QSGMII_PCS_ALL_CH_CTL			0x80
++#define QSGMII_PCS_CH_SPEED_FORCE		0x2
++#define QSGMII_PCS_CH_SPEED_10			0x0
++#define QSGMII_PCS_CH_SPEED_100			0x4
++#define QSGMII_PCS_CH_SPEED_1000		0x8
++#define QSGMII_PCS_CH_SPEED_MASK		(QSGMII_PCS_CH_SPEED_FORCE | \
++						 QSGMII_PCS_CH_SPEED_10 | \
++						 QSGMII_PCS_CH_SPEED_100 | \
++						 QSGMII_PCS_CH_SPEED_1000)
++#define QSGMII_PCS_CH_SPEED_SHIFT(x)		(x * 4)
++
+ #define QSGMII_PCS_CAL_LCKDT_CTL		0x120
+ #define QSGMII_PCS_CAL_LCKDT_CTL_RST		BIT(19)
+ 
+@@ -345,6 +356,12 @@ static int ipq806x_gmac_probe(struct pla
+ 			     0x1ul << QSGMII_PHY_RX_INPUT_EQU_OFFSET |
+ 			     0x2ul << QSGMII_PHY_CDR_PI_SLEW_OFFSET |
+ 			     0xCul << QSGMII_PHY_TX_DRV_AMP_OFFSET);
++
++		regmap_update_bits(gmac->qsgmii_csr,
++				   QSGMII_PCS_ALL_CH_CTL,
++				   QSGMII_PCS_CH_SPEED_MASK <<
++				    QSGMII_PCS_CH_SPEED_SHIFT(gmac->id),
++				   0);
+ 	}
+ 
+ 	plat_dat->has_gmac = true;
-- 
2.27.0