netdev - [PATCH] net: sh_eth: fix mdio access in sh_eth

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Date:   Wed, 15 May 2019 14:36:41 +0900
From:   Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To:     sergei.shtylyov@...entembedded.com, davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Subject: [PATCH] net: sh_eth: fix mdio access in sh_eth_close() for some SoCs

The sh_eth_close() resets the MAC and then calls phy_stop()
so that mdio read access result is incorrect without any error
according to kernel trace like below:

ifconfig-216   [003] .n..   109.133124: mdio_access: ee700000.ethernet-ffffffff read  phy:0x01 reg:0x00 val:0xffff

To fix the issue, this patch adds a condition and set the RMII mode
regiseter in sh_eth_dev_exit() for some SoCs.

Note that when I have tried to move the sh_eth_dev_exit() calling
after phy_stop() on sh_eth_close(), but it gets worse.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
---
 drivers/net/ethernet/renesas/sh_eth.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index e33af37..106ae90 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1596,6 +1596,10 @@ static void sh_eth_dev_exit(struct net_device *ndev)
 
 	/* Set MAC address again */
 	update_mac_address(ndev);
+
+	/* Set the mode again if required */
+	if (mdp->cd->rmiimode)
+		sh_eth_write(ndev, 0x1, RMIIMODE);
 }
 
 static void sh_eth_rx_csum(struct sk_buff *skb)
-- 
2.7.4