[RFC PATCH net-next v2 12/17] net: dsa: qca8k: dsa: qca8k: protect MASTER busy_wait with mdio mutex
From: Ansuel Smith <ansuelsmth@gmail.com>
Date: 2021-05-02 23:10:01
Also in:
lkml
Subsystem:
networking drivers, networking [dsa], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Andrew Lunn, Vladimir Oltean, Linus Torvalds
MDIO_MASTER operation have a dedicated busy wait that is not protected by the mdio mutex. This can cause situation where the MASTER operation is done and a normal operation is executed between the MASTER read/write and the MASTER busy_wait. Rework the qca8k_mdio_read/write function to address this issue by binding the lock for the whole MASTER operation and not only the mdio read/write common operation. Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com> --- drivers/net/dsa/qca8k.c | 69 ++++++++++++++++++++++++++++++++++------- 1 file changed, 57 insertions(+), 12 deletions(-)
diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index f64e3215a515..9a1b28bcaff0 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c@@ -617,9 +617,33 @@ qca8k_port_to_phy(int port) return port - 1; } +static int +qca8k_mdio_busy_wait(struct qca8k_priv *priv, u32 reg, u32 mask) +{ + unsigned long timeout; + u16 r1, r2, page; + + qca8k_split_addr(reg, &r1, &r2, &page); + + timeout = jiffies + msecs_to_jiffies(20); + + /* loop until the busy flag has cleared */ + do { + u32 val = qca8k_mii_read32(priv->bus, 0x10 | r2, r1); + int busy = val & mask; + + if (!busy) + break; + cond_resched(); + } while (!time_after_eq(jiffies, timeout)); + + return time_after_eq(jiffies, timeout); +} + static int qca8k_mdio_write(struct qca8k_priv *priv, int port, u32 regnum, u16 data) { + u16 r1, r2, page; u32 phy, val; int ret;
@@ -635,12 +659,22 @@ qca8k_mdio_write(struct qca8k_priv *priv, int port, u32 regnum, u16 data) QCA8K_MDIO_MASTER_REG_ADDR(regnum) | QCA8K_MDIO_MASTER_DATA(data); - ret = qca8k_write(priv, QCA8K_MDIO_MASTER_CTRL, val); + qca8k_split_addr(QCA8K_MDIO_MASTER_CTRL, &r1, &r2, &page); + + mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); + + ret = qca8k_set_page(priv->bus, page); if (ret) - return ret; + goto exit; + + qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val); - ret = qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL, - QCA8K_MDIO_MASTER_BUSY); + if (qca8k_mdio_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL, + QCA8K_MDIO_MASTER_BUSY)) + ret = -ETIMEDOUT; + +exit: + mutex_unlock(&priv->bus->mdio_lock); /* even if the busy_wait timeouts try to clear the MASTER_EN */ qca8k_reg_clear(priv, QCA8K_MDIO_MASTER_CTRL,
@@ -652,6 +686,7 @@ qca8k_mdio_write(struct qca8k_priv *priv, int port, u32 regnum, u16 data) static int qca8k_mdio_read(struct qca8k_priv *priv, int port, u32 regnum) { + u16 r1, r2, page; u32 phy, val; int ret;
@@ -666,20 +701,30 @@ qca8k_mdio_read(struct qca8k_priv *priv, int port, u32 regnum) QCA8K_MDIO_MASTER_READ | QCA8K_MDIO_MASTER_PHY_ADDR(phy) | QCA8K_MDIO_MASTER_REG_ADDR(regnum); - ret = qca8k_write(priv, QCA8K_MDIO_MASTER_CTRL, val); - if (ret) - return ret; + qca8k_split_addr(QCA8K_MDIO_MASTER_CTRL, &r1, &r2, &page); - if (qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL, - QCA8K_MDIO_MASTER_BUSY)) - return -ETIMEDOUT; + mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); - ret = qca8k_read(priv, QCA8K_MDIO_MASTER_CTRL, &val); + ret = qca8k_set_page(priv->bus, page); if (ret) - return ret; + goto exit; + + qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val); + + if (qca8k_mdio_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL, + QCA8K_MDIO_MASTER_BUSY)) + val = -ETIMEDOUT; + else + val = qca8k_mii_read32(priv->bus, 0x10 | r2, r1); val &= QCA8K_MDIO_MASTER_DATA_MASK; +exit: + mutex_unlock(&priv->bus->mdio_lock); + + if (val >= 0) + val &= QCA8K_MDIO_MASTER_DATA_MASK; + /* even if the busy_wait timeouts try to clear the MASTER_EN */ qca8k_reg_clear(priv, QCA8K_MDIO_MASTER_CTRL, QCA8K_MDIO_MASTER_EN);
--
2.30.2