linux-kernel - [PATCH 3.16 031/178] net: bcmgenet: Power up the internal PHY before probing the MII

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Message-ID: <lsq.1500213406.367510681@decadent.org.uk>
Date:   Sun, 16 Jul 2017 14:56:46 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Doug Berger" <opendmb@...il.com>,
        "Florian Fainelli" <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 3.16 031/178] net: bcmgenet: Power up the internal PHY
 before probing the MII

3.16.46-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Doug Berger <opendmb@...il.com>

commit 6be371b053dc86f11465cc1abce2e99bda0a0574 upstream.

When using the internal PHY it must be powered up when the MII is probed
or the PHY will not be detected.  Since the PHY is powered up at reset
this has not been a problem.  However, when the kernel is restarted with
kexec the PHY will likely be powered down when the kernel starts so it
will not be detected and the Ethernet link will not be established.

This commit explicitly powers up the internal PHY when the GENET driver
is probed to correct this behavior.

Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file")
Signed-off-by: Doug Berger <opendmb@...il.com>
Reviewed-by: Florian Fainelli <f.fainelli@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/net/ethernet/broadcom/genet/bcmgenet.c | 8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -2500,6 +2500,7 @@ static int bcmgenet_probe(struct platfor
 	const void *macaddr;
 	struct resource *r;
 	int err = -EIO;
+	const char *phy_mode_str;
 
 	/* Up to GENET_MAX_MQ_CNT + 1 TX queues and a single RX queue */
 	dev = alloc_etherdev_mqs(sizeof(*priv), GENET_MAX_MQ_CNT + 1, 1);
@@ -2581,6 +2582,13 @@ static int bcmgenet_probe(struct platfor
 	if (!IS_ERR(priv->clk))
 		clk_prepare_enable(priv->clk);
 
+	/* If this is an internal GPHY, power it on now, before UniMAC is
+	 * brought out of reset as absolutely no UniMAC activity is allowed
+	 */
+	if (dn && !of_property_read_string(dn, "phy-mode", &phy_mode_str) &&
+	    !strcasecmp(phy_mode_str, "internal"))
+		bcmgenet_power_up(priv, GENET_POWER_PASSIVE);
+
 	err = reset_umac(priv);
 	if (err)
 		goto err_clk_disable;