[PATCH net-next 1/2] net: phy: at803x: use paged reads

[David Bauer]

Refactor the page-switching in at803x_aneg_done to use
paged reads as suggested by Andrew Lunn.

This way, potential race conditions are avoided, as the
MDIO lock was previously not taken.

Suggested-by: Andrew Lunn <and...@lunn.ch>
Signed-off-by: David Bauer <m...@david-bauer.net>
---
 drivers/net/phy/at803x.c | 42 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index c2aa4c92edde..b3243ad570c7 100644
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -144,6 +144,9 @@
 #define ATH8035_PHY_ID 0x004dd072
 #define AT8030_PHY_ID_MASK                     0xffffffef
 
+#define AT803X_PAGE_FIBER              0
+#define AT803X_PAGE_COPPER             1
+
 MODULE_DESCRIPTION("Qualcomm Atheros AR803x PHY driver");
 MODULE_AUTHOR("Matus Ujhelyi");
 MODULE_LICENSE("GPL");
@@ -198,6 +201,35 @@ static int at803x_debug_reg_mask(struct phy_device 
*phydev, u16 reg,
        return phy_write(phydev, AT803X_DEBUG_DATA, val);
 }
 
+static int at803x_write_page(struct phy_device *phydev, int page)
+{
+       int mask;
+       int set;
+
+       if (page == AT803X_PAGE_COPPER) {
+               set = AT803X_BT_BX_REG_SEL;
+               mask = 0;
+       } else {
+               set = 0;
+               mask = AT803X_BT_BX_REG_SEL;
+       }
+
+       return __phy_modify(phydev, AT803X_REG_CHIP_CONFIG, mask, set);
+}
+
+static int at803x_read_page(struct phy_device *phydev)
+{
+       int ccr = __phy_read(phydev, AT803X_REG_CHIP_CONFIG);
+
+       if (ccr < 0)
+               return ccr;
+
+       if (ccr & AT803X_BT_BX_REG_SEL)
+               return AT803X_PAGE_COPPER;
+
+       return AT803X_PAGE_FIBER;
+}
+
 static int at803x_enable_rx_delay(struct phy_device *phydev)
 {
        return at803x_debug_reg_mask(phydev, AT803X_DEBUG_REG_0, 0,
@@ -753,6 +785,7 @@ static void at803x_link_change_notify(struct phy_device 
*phydev)
 
 static int at803x_aneg_done(struct phy_device *phydev)
 {
+       int pssr;
        int ccr;
 
        int aneg_done = genphy_aneg_done(phydev);
@@ -767,16 +800,13 @@ static int at803x_aneg_done(struct phy_device *phydev)
        if ((ccr & AT803X_MODE_CFG_MASK) != AT803X_MODE_CFG_SGMII)
                return aneg_done;
 
-       /* switch to SGMII/fiber page */
-       phy_write(phydev, AT803X_REG_CHIP_CONFIG, ccr & ~AT803X_BT_BX_REG_SEL);
+       pssr = phy_read_paged(phydev, AT803X_PAGE_FIBER, AT803X_PSSR);
 
        /* check if the SGMII link is OK. */
-       if (!(phy_read(phydev, AT803X_PSSR) & AT803X_PSSR_MR_AN_COMPLETE)) {
+       if (!(pssr & AT803X_PSSR_MR_AN_COMPLETE)) {
                phydev_warn(phydev, "803x_aneg_done: SGMII link is not ok\n");
                aneg_done = 0;
        }
-       /* switch back to copper page */
-       phy_write(phydev, AT803X_REG_CHIP_CONFIG, ccr | AT803X_BT_BX_REG_SEL);
 
        return aneg_done;
 }
@@ -1196,6 +1226,8 @@ static struct phy_driver at803x_driver[] = {
        .get_wol                = at803x_get_wol,
        .suspend                = at803x_suspend,
        .resume                 = at803x_resume,
+       .read_page              = at803x_read_page,
+       .write_page             = at803x_write_page,
        /* PHY_GBIT_FEATURES */
        .read_status            = at803x_read_status,
        .aneg_done              = at803x_aneg_done,
-- 
2.31.1