netdev - [PATCH] net: macb: do not disable MDIO bus when closing interface

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Date:   Wed,  8 Aug 2018 15:19:01 +0300
From:   Anssi Hannula <anssi.hannula@...wise.fi>
To:     Nicolas Ferre <nicolas.ferre@...rochip.com>,
        "David S. Miller" <davem@...emloft.net>
Cc:     netdev@...r.kernel.org
Subject: [PATCH] net: macb: do not disable MDIO bus when closing interface

macb_close() calls macb_reset_hw() which zeroes NCR register, including
the MPE (Management Port Enable) bit.

This will prevent accessing any other PHYs for other Ethernet MACs on
the MDIO bus which is still registered.

Fix that by keeping the MPE bit set.

Signed-off-by: Anssi Hannula <anssi.hannula@...wise.fi>
---
 drivers/net/ethernet/cadence/macb_main.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index dc09f9a8a49b..3ca98fc32144 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -2030,12 +2030,13 @@ static void macb_reset_hw(struct macb *bp)
 	unsigned int q;
 
 	/* Disable RX and TX (XXX: Should we halt the transmission
-	 * more gracefully?)
+	 * more gracefully?) but keep management port open since there
+	 * may be other users of the mdio bus
 	 */
-	macb_writel(bp, NCR, 0);
+	macb_writel(bp, NCR, MACB_BIT(MPE));
 
 	/* Clear the stats registers (XXX: Update stats first?) */
-	macb_writel(bp, NCR, MACB_BIT(CLRSTAT));
+	macb_writel(bp, NCR, MACB_BIT(CLRSTAT) | MACB_BIT(MPE));
 
 	/* Clear all status flags */
 	macb_writel(bp, TSR, -1);
-- 
2.16.3