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net: phy: mscc: fix deadlock in vsc85xx_default_config

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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: 6a0bfbbe20 ("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>
This commit is contained in:
Quentin Schulz 2018-11-23 19:01:51 +01:00 committed by David S. Miller
parent e7b9fb4f54
commit 3fa528b768
1 changed files with 5 additions and 9 deletions
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14
drivers/net/phy/mscc.c
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@ -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;