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From 60df02b6ea4581d72eb7a3ab7204504a54059b72 Mon Sep 17 00:00:00 2001
From: Ansuel Smith <ansuelsmth@gmail.com>
Date: Fri, 14 May 2021 23:00:08 +0200
Subject: [PATCH] net: dsa: qca8k: dsa: qca8k: protect MASTER busy_wait with
mdio mutex
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>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/dsa/qca8k.c | 68 +++++++++++++++++++++++++++++++++--------
1 file changed, 55 insertions(+), 13 deletions(-)
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -628,8 +628,31 @@ qca8k_port_to_phy(int port)
}
static int
+qca8k_mdio_busy_wait(struct qca8k_priv *priv, u32 reg, u32 mask)
+{
+ u16 r1, r2, page;
+ u32 val;
+ int ret;
+
+ qca8k_split_addr(reg, &r1, &r2, &page);
+
+ ret = read_poll_timeout(qca8k_mii_read32, val, !(val & mask), 0,
+ QCA8K_BUSY_WAIT_TIMEOUT * USEC_PER_MSEC, false,
+ priv->bus, 0x10 | r2, r1);
+
+ /* Check if qca8k_read has failed for a different reason
+ * before returnting -ETIMEDOUT
+ */
+ if (ret < 0 && val < 0)
+ return val;
+
+ return ret;
+}
+
+static int
qca8k_mdio_write(struct qca8k_priv *priv, int port, u32 regnum, u16 data)
{
+ u16 r1, r2, page;
u32 phy, val;
int ret;
@@ -645,12 +668,21 @@ qca8k_mdio_write(struct qca8k_priv *priv
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);
+ ret = qca8k_mdio_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,
+ QCA8K_MDIO_MASTER_BUSY);
+
+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,
@@ -662,6 +694,7 @@ qca8k_mdio_write(struct qca8k_priv *priv
static int
qca8k_mdio_read(struct qca8k_priv *priv, int port, u32 regnum)
{
+ u16 r1, r2, page;
u32 phy, val;
int ret;
@@ -676,21 +709,30 @@ qca8k_mdio_read(struct qca8k_priv *priv,
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);
+
+ mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
- ret = qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,
- QCA8K_MDIO_MASTER_BUSY);
+ ret = qca8k_set_page(priv->bus, page);
if (ret)
- return ret;
+ goto exit;
- val = qca8k_read(priv, QCA8K_MDIO_MASTER_CTRL);
- if (val < 0)
- return val;
+ qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val);
+
+ ret = qca8k_mdio_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,
+ QCA8K_MDIO_MASTER_BUSY);
+ if (ret)
+ goto exit;
+ 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);
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