From 3fa528b7682e73e906266bcd43728b8f923bf9b2 Mon Sep 17 00:00:00 2001
From: Quentin Schulz <quentin.schulz@bootlin.com>
Date: Fri, 23 Nov 2018 19:01:51 +0100
Subject: [PATCH] net: phy: mscc: fix deadlock in vsc85xx_default_config
The vsc85xx_default_config function called in the vsc85xx_config_init
function which is used by VSC8530, VSC8531, VSC8540 and VSC8541 PHYs
mistakenly calls phy_read and phy_write in-between phy_select_page and
phy_restore_page.
phy_select_page and phy_restore_page actually take and release the MDIO
bus lock and phy_write and phy_read take and release the lock to write
or read to a PHY register.
Let's fix this deadlock by using phy_modify_paged which handles
correctly a read followed by a write in a non-standard page.
Fixes: 6a0bfbbe20b0 ("net: phy: mscc: migrate to phy_select/restore_page functions")
Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/phy/mscc.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/drivers/net/phy/mscc.c b/drivers/net/phy/mscc.c
index a2e59f4f6f01f..7cae175177449 100644
--- a/drivers/net/phy/mscc.c
+++ b/drivers/net/phy/mscc.c
@@ -810,17 +810,13 @@ static int vsc85xx_default_config(struct phy_device *phydev)
phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
mutex_lock(&phydev->lock);
- rc = phy_select_page(phydev, MSCC_PHY_PAGE_EXTENDED_2);
- if (rc < 0)
- goto out_unlock;
- reg_val = phy_read(phydev, MSCC_PHY_RGMII_CNTL);
- reg_val &= ~(RGMII_RX_CLK_DELAY_MASK);
- reg_val |= (RGMII_RX_CLK_DELAY_1_1_NS << RGMII_RX_CLK_DELAY_POS);
- phy_write(phydev, MSCC_PHY_RGMII_CNTL, reg_val);
+ reg_val = RGMII_RX_CLK_DELAY_1_1_NS << RGMII_RX_CLK_DELAY_POS;
+
+ rc = phy_modify_paged(phydev, MSCC_PHY_PAGE_EXTENDED_2,
+ MSCC_PHY_RGMII_CNTL, RGMII_RX_CLK_DELAY_MASK,
+ reg_val);
-out_unlock:
- rc = phy_restore_page(phydev, rc, rc > 0 ? 0 : rc);
mutex_unlock(&phydev->lock);
return rc;
--
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