[PATCH v3 net 3/5] amd-xgbe: enable PLL_CTL for fixed PHY modes only

[Raju Rangoju <Raju.Rangoju@amd.com>]

PLL control setting(RRC) is needed only in fixed PHY configuration to
fix the peer-peer issues. Without the PLL control setting, the link up
takes longer time in a fixed phy configuration.

Driver implements SW RRC for Autoneg On configuration, hence PLL control
setting (RRC) is not needed for AN On configuration, and can be skipped.

Also, PLL re-initialization is not needed for PHY Power Off and RRC
commands. Otherwise, they lead to mailbox errors. Added the changes
accordingly.

Fixes: daf182d360e5 ("net: amd-xgbe: Toggle PLL settings during rate change")
Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com>
---
Changes since v2:
 - update the POWER_OFF and RRC enumerations
 - updated the commit message to use RRC instead of RRCM

Changes since v1:
- used enums for all mailxbox command and subcommands, pre-patch to this
  contains the enum updates
- updated the comment section to include RRC command
- updated the commit message to use RRC instead of RRCM

 drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
index 8cf5d81fca36..349ba0dc1fa2 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
@@ -1979,6 +1979,10 @@ static void xgbe_phy_rx_reset(struct xgbe_prv_data *pdata)
 
 static void xgbe_phy_pll_ctrl(struct xgbe_prv_data *pdata, bool enable)
 {
+	/* PLL_CTRL feature needs to be enabled for fixed PHY modes (Non-Autoneg) only */
+	if (pdata->phy.autoneg != AUTONEG_DISABLE)
+		return;
+
 	XMDIO_WRITE_BITS(pdata, MDIO_MMD_PMAPMD, MDIO_VEND2_PMA_MISC_CTRL0,
 			 XGBE_PMA_PLL_CTRL_MASK,
 			 enable ? XGBE_PMA_PLL_CTRL_ENABLE
@@ -2029,8 +2033,10 @@ static void xgbe_phy_perform_ratechange(struct xgbe_prv_data *pdata,
 	xgbe_phy_rx_reset(pdata);
 
 reenable_pll:
-	/* Enable PLL re-initialization */
-	xgbe_phy_pll_ctrl(pdata, true);
+	/* Enable PLL re-initialization, not needed for PHY Power Off and RRC cmds */
+	if (cmd != XGBE_MB_CMD_POWER_OFF &&
+	    cmd != XGBE_MB_CMD_RRC)
+		xgbe_phy_pll_ctrl(pdata, true);
 }
 
 static void xgbe_phy_rrc(struct xgbe_prv_data *pdata)
-- 
2.25.1