netdev - [net,v3] net: amd-xgbe: Toggle PLL settings during rate change

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Date:   Wed, 27 Oct 2021 15:27:27 +0530
From:   Shyam Sundar S K <Shyam-sundar.S-k@....com>
To:     Tom Lendacky <thomas.lendacky@....com>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
CC:     <netdev@...r.kernel.org>, <Raju.Rangoju@....com>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        Sudheesh Mavila <sudheesh.mavila@....com>
Subject: [net,v3] net: amd-xgbe: Toggle PLL settings during rate change

For each rate change command submission, the FW has to do a phy
power off sequence internally. For this to happen correctly, the
PLL re-initialization control setting has to be turned off before
sending mailbox commands and re-enabled once the command submission
is complete.

Without the PLL control setting, the link up takes longer time in a
fixed phy configuration.

Fixes: 47f164deab22 ("amd-xgbe: Add PCI device support")
Co-developed-by: Sudheesh Mavila <sudheesh.mavila@....com>
Signed-off-by: Sudheesh Mavila <sudheesh.mavila@....com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>
Acked-by: Tom Lendacky <thomas.lendacky@....com>
---
v1->v2:
- Add Co-Developed-by: tag

v2->v3:
- Code Alignment
- Add Fixes: tag
- Add more information in the commit message.

 drivers/net/ethernet/amd/xgbe/xgbe-common.h |  8 ++++++++
 drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c | 20 +++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-common.h b/drivers/net/ethernet/amd/xgbe/xgbe-common.h
index b2cd3bdba9f8..533b8519ec35 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-common.h
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-common.h
@@ -1331,6 +1331,10 @@
 #define MDIO_VEND2_PMA_CDR_CONTROL	0x8056
 #endif
 
+#ifndef MDIO_VEND2_PMA_MISC_CTRL0
+#define MDIO_VEND2_PMA_MISC_CTRL0	0x8090
+#endif
+
 #ifndef MDIO_CTRL1_SPEED1G
 #define MDIO_CTRL1_SPEED1G		(MDIO_CTRL1_SPEED10G & ~BMCR_SPEED100)
 #endif
@@ -1389,6 +1393,10 @@
 #define XGBE_PMA_RX_RST_0_RESET_ON	0x10
 #define XGBE_PMA_RX_RST_0_RESET_OFF	0x00
 
+#define XGBE_PMA_PLL_CTRL_MASK		BIT(15)
+#define XGBE_PMA_PLL_CTRL_ENABLE	BIT(15)
+#define XGBE_PMA_PLL_CTRL_DISABLE	0x0000
+
 /* Bit setting and getting macros
  *  The get macro will extract the current bit field value from within
  *  the variable
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
index 18e48b3bc402..213769054391 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
@@ -1977,12 +1977,26 @@ static void xgbe_phy_rx_reset(struct xgbe_prv_data *pdata)
 	}
 }
 
+static void xgbe_phy_pll_ctrl(struct xgbe_prv_data *pdata, bool enable)
+{
+	XMDIO_WRITE_BITS(pdata, MDIO_MMD_PMAPMD, MDIO_VEND2_PMA_MISC_CTRL0,
+			 XGBE_PMA_PLL_CTRL_MASK,
+			 enable ? XGBE_PMA_PLL_CTRL_ENABLE
+				: XGBE_PMA_PLL_CTRL_DISABLE);
+
+	/* Wait for command to complete */
+	usleep_range(100, 200);
+}
+
 static void xgbe_phy_perform_ratechange(struct xgbe_prv_data *pdata,
 					unsigned int cmd, unsigned int sub_cmd)
 {
 	unsigned int s0 = 0;
 	unsigned int wait;
 
+	/* Disable PLL re-initialization during FW command processing */
+	xgbe_phy_pll_ctrl(pdata, false);
+
 	/* Log if a previous command did not complete */
 	if (XP_IOREAD_BITS(pdata, XP_DRIVER_INT_RO, STATUS)) {
 		netif_dbg(pdata, link, pdata->netdev,
@@ -2003,7 +2017,7 @@ static void xgbe_phy_perform_ratechange(struct xgbe_prv_data *pdata,
 	wait = XGBE_RATECHANGE_COUNT;
 	while (wait--) {
 		if (!XP_IOREAD_BITS(pdata, XP_DRIVER_INT_RO, STATUS))
-			return;
+			goto reenable_pll;
 
 		usleep_range(1000, 2000);
 	}
@@ -2013,6 +2027,10 @@ static void xgbe_phy_perform_ratechange(struct xgbe_prv_data *pdata,
 
 	/* Reset on error */
 	xgbe_phy_rx_reset(pdata);
+
+reenable_pll:
+	/* Enable PLL re-initialization */
+	xgbe_phy_pll_ctrl(pdata, true);
 }
 
 static void xgbe_phy_rrc(struct xgbe_prv_data *pdata)
-- 
2.25.1