[PATCH net-next 1/3] net: phy: micrel: Fix concurrent register access

Divya Koppera
2022-03-04T09:36:33Z

Make Extended page register accessing atomic,
to overcome unexpected output from register
reads/writes.

Fixes: 7c2dcfa295b1 ("net: phy: micrel: Add support for LAN8804 PHY")
Signed-off-by: Divya Koppera<Divya.Koppera@microchip.com>
---
drivers/net/phy/micrel.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index a7ebcdab415b..281cebc3d00c 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -1596,11 +1596,13 @@ static int lanphy_read_page_reg(struct phy_device *phydev, int page, u32 addr)
{
u32 data;

- phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL, page);
- phy_write(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA, addr);
- phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL,
- (page | LAN_EXT_PAGE_ACCESS_CTRL_EP_FUNC));
- data = phy_read(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA);
+ phy_lock_mdio_bus(phydev);
+ __phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL, page);
+ __phy_write(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA, addr);
+ __phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL,
+ (page | LAN_EXT_PAGE_ACCESS_CTRL_EP_FUNC));
+ data = __phy_read(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA);
+ phy_unlock_mdio_bus(phydev);

return data;
}
@@ -1608,18 +1610,18 @@ static int lanphy_read_page_reg(struct phy_device *phydev, int page, u32 addr)
static int lanphy_write_page_reg(struct phy_device *phydev, int page, u16 addr,
u16 val)
{
- phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL, page);
- phy_write(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA, addr);
- phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL,
- (page | LAN_EXT_PAGE_ACCESS_CTRL_EP_FUNC));
+ phy_lock_mdio_bus(phydev);
+ __phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL, page);
+ __phy_write(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA, addr);
+ __phy_write(phydev, LAN_EXT_PAGE_ACCESS_CONTROL,
+ page | LAN_EXT_PAGE_ACCESS_CTRL_EP_FUNC);

- val = phy_write(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA, val);
- if (val) {
+ val = __phy_write(phydev, LAN_EXT_PAGE_ACCESS_ADDRESS_DATA, val);
+ if (val != 0)
phydev_err(phydev, "Error: phy_write has returned error %d\n",
val);
- return val;
- }
- return 0;
+ phy_unlock_mdio_bus(phydev);
+ return val;
}

static int lan8814_config_init(struct phy_device *phydev)
--
2.17.1