linux-kernel - [PATCH] net: qcom/emac: Reduce timeout for mdio read/write

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Date:   Fri, 15 Dec 2017 20:05:58 +0530
From:   Hemanth Puranik <hpuranik@...eaurora.org>
To:     netdev <netdev@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Cc:     Timur Tabi <timur@...eaurora.org>,
        Hemanth Puranik <hpuranik@...eaurora.org>
Subject: [PATCH] net: qcom/emac: Reduce timeout for mdio read/write

Currently mdio read/write takes around ~115us as the timeout
between status check is set to 100us.
By reducing the timeout to 1us mdio read/write takes ~15us to
complete. This improves the link up event response.

Signed-off-by: Hemanth Puranik <hpuranik@...eaurora.org>
---
 drivers/net/ethernet/qualcomm/emac/emac-phy.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac-phy.c b/drivers/net/ethernet/qualcomm/emac/emac-phy.c
index 18461fc..53dbf1e 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac-phy.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac-phy.c
@@ -47,6 +47,7 @@
 #define MDIO_CLK_25_28                                               7
 
 #define MDIO_WAIT_TIMES                                           1000
+#define MDIO_STATUS_DELAY_TIME                                       1
 
 static int emac_mdio_read(struct mii_bus *bus, int addr, int regnum)
 {
@@ -65,7 +66,7 @@ static int emac_mdio_read(struct mii_bus *bus, int addr, int regnum)
 
 	if (readl_poll_timeout(adpt->base + EMAC_MDIO_CTRL, reg,
 			       !(reg & (MDIO_START | MDIO_BUSY)),
-			       100, MDIO_WAIT_TIMES * 100))
+			       MDIO_STATUS_DELAY_TIME, MDIO_WAIT_TIMES * 100))
 		return -EIO;
 
 	return (reg >> MDIO_DATA_SHFT) & MDIO_DATA_BMSK;
@@ -88,8 +89,8 @@ static int emac_mdio_write(struct mii_bus *bus, int addr, int regnum, u16 val)
 	writel(reg, adpt->base + EMAC_MDIO_CTRL);
 
 	if (readl_poll_timeout(adpt->base + EMAC_MDIO_CTRL, reg,
-			       !(reg & (MDIO_START | MDIO_BUSY)), 100,
-			       MDIO_WAIT_TIMES * 100))
+			       !(reg & (MDIO_START | MDIO_BUSY)),
+			       MDIO_STATUS_DELAY_TIME, MDIO_WAIT_TIMES * 100))
 		return -EIO;
 
 	return 0;
-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.