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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>
This commit is contained in:
Ansuel Smith 2021-05-14 23:00:08 +02:00 committed by David S. Miller
parent 63c33bbfeb
commit 60df02b6ea
1 changed files with 56 additions and 14 deletions
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70
drivers/net/dsa/qca8k.c
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@ -627,9 +627,32 @@ qca8k_port_to_phy(int port)
return port - 1;
}
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, 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);
if (ret)
return ret;
qca8k_split_addr(QCA8K_MDIO_MASTER_CTRL, &r1, &r2, &page);
ret = qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,
QCA8K_MDIO_MASTER_BUSY);
mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
ret = qca8k_set_page(priv->bus, page);
if (ret)
goto exit;
qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val);
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, 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;
@ -676,21 +709,30 @@ 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);
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;
ret = qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,
QCA8K_MDIO_MASTER_BUSY);
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)
return ret;
val = qca8k_read(priv, QCA8K_MDIO_MASTER_CTRL);
if (val < 0)
return val;
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);