Commit 60df02b6 authored by Ansuel Smith's avatar Ansuel Smith Committed by David S. Miller
Browse files

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: default avatarAnsuel Smith <ansuelsmth@gmail.com>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 63c33bbf

drivers/net/dsa/qca8k.c

+55 −13
Original line number Diff line number Diff line
@@ -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;
@@ -645,13 +668,22 @@ 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;



	ret = qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,

	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,

			QCA8K_MDIO_MASTER_EN);
@@ -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;
@@ -676,19 +709,28 @@ 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;



	qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val);



	ret = qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,

	ret = qca8k_mdio_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,

				   QCA8K_MDIO_MASTER_BUSY);

	if (ret)

		return ret;

		goto exit;



	val = qca8k_read(priv, QCA8K_MDIO_MASTER_CTRL);

	if (val < 0)

		return val;

	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 */