[PATCH 5.4 023/155] net: phy: dp83867: w/a for fld detect threshold bootstrapping issue

Greg Kroah-Hartman
2020-03-31T09:13:52Z

From: Grygorii Strashko <grygorii.strashko@ti.com>

[ Upstream commit 749f6f6843115b424680f1aada3c0dd613ad807c ]

When the DP83867 PHY is strapped to enable Fast Link Drop (FLD) feature
STRAP_STS2.STRAP_ FLD (reg 0x006F bit 10), the Energy Lost Threshold for
FLD Energy Lost Mode FLD_THR_CFG.ENERGY_LOST_FLD_THR (reg 0x002e bits 2:0)
will be defaulted to 0x2. This may cause the phy link to be unstable. The
new DP83867 DM recommends to always restore ENERGY_LOST_FLD_THR to 0x1.

Hence, restore default value of FLD_THR_CFG.ENERGY_LOST_FLD_THR to 0x1 when
FLD is enabled by bootstrapping as recommended by DM.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/phy/dp83867.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)

--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -25,7 +25,8 @@
#define DP83867_CFG3 0x1e

/* Extended Registers */
-#define DP83867_CFG4 0x0031
+#define DP83867_FLD_THR_CFG 0x002e
+#define DP83867_CFG4 0x0031
#define DP83867_CFG4_SGMII_ANEG_MASK (BIT(5) | BIT(6))
#define DP83867_CFG4_SGMII_ANEG_TIMER_11MS (3 << 5)
#define DP83867_CFG4_SGMII_ANEG_TIMER_800US (2 << 5)
@@ -74,6 +75,7 @@
#define DP83867_STRAP_STS2_CLK_SKEW_RX_MASK GENMASK(2, 0)
#define DP83867_STRAP_STS2_CLK_SKEW_RX_SHIFT 0
#define DP83867_STRAP_STS2_CLK_SKEW_NONE BIT(2)
+#define DP83867_STRAP_STS2_STRAP_FLD BIT(10)

/* PHY CTRL bits */
#define DP83867_PHYCR_FIFO_DEPTH_SHIFT 14
@@ -103,6 +105,9 @@
/* CFG4 bits */
#define DP83867_CFG4_PORT_MIRROR_EN BIT(0)

+/* FLD_THR_CFG */
+#define DP83867_FLD_THR_CFG_ENERGY_LOST_THR_MASK 0x7
+
enum {
DP83867_PORT_MIRROING_KEEP,
DP83867_PORT_MIRROING_EN,
@@ -318,6 +323,20 @@ static int dp83867_config_init(struct ph
phy_clear_bits_mmd(phydev, DP83867_DEVADDR, DP83867_CFG4,
BIT(7));

+ bs = phy_read_mmd(phydev, DP83867_DEVADDR, DP83867_STRAP_STS2);
+ if (bs & DP83867_STRAP_STS2_STRAP_FLD) {
+ /* When using strap to enable FLD, the ENERGY_LOST_FLD_THR will
+ * be set to 0x2. This may causes the PHY link to be unstable -
+ * the default value 0x1 need to be restored.
+ */
+ ret = phy_modify_mmd(phydev, DP83867_DEVADDR,
+ DP83867_FLD_THR_CFG,
+ DP83867_FLD_THR_CFG_ENERGY_LOST_THR_MASK,
+ 0x1);
+ if (ret)
+ return ret;
+ }
+
if (phy_interface_is_rgmii(phydev)) {
val = phy_read(phydev, MII_DP83867_PHYCTRL);
if (val < 0)