linux-kernel - [PATCH net-next 1/4] net: phy: mscc-miim: use more reasonable delays

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Date:   Tue, 26 May 2020 18:22:53 +0200
From:   Antoine Tenart <antoine.tenart@...tlin.com>
To:     davem@...emloft.net, andrew@...n.ch, f.fainelli@...il.com,
        hkallweit1@...il.com
Cc:     Antoine Tenart <antoine.tenart@...tlin.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        alexandre.belloni@...tlin.com, thomas.petazzoni@...tlin.com,
        allan.nielsen@...rochip.com
Subject: [PATCH net-next 1/4] net: phy: mscc-miim: use more reasonable delays

The MSCC MIIM MDIO driver uses delays to read poll a status register. I
made multiple tests on a Ocelot PCS120 platform which led me to reduce
those delays. The delay in between which the polling function is allowed
to sleep is reduced from 100us to 50us which in almost all cases is a
good value to succeed at the first retry. The overall delay is also
lowered as the prior value was really way to high, 10000us is large
enough.

Signed-off-by: Antoine Tenart <antoine.tenart@...tlin.com>
---
 drivers/net/phy/mdio-mscc-miim.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/mdio-mscc-miim.c b/drivers/net/phy/mdio-mscc-miim.c
index badbc99bedd3..0b7544f593fb 100644
--- a/drivers/net/phy/mdio-mscc-miim.c
+++ b/drivers/net/phy/mdio-mscc-miim.c
@@ -44,7 +44,7 @@ static int mscc_miim_wait_ready(struct mii_bus *bus)
 	u32 val;
 
 	readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
-			   !(val & MSCC_MIIM_STATUS_STAT_BUSY), 100, 250000);
+			   !(val & MSCC_MIIM_STATUS_STAT_BUSY), 50, 10000);
 	if (val & MSCC_MIIM_STATUS_STAT_BUSY)
 		return -ETIMEDOUT;
 
-- 
2.26.2