kernel: 5.10: backport qca8k stability improvements

[openwrt/openwrt.git] / target / linux / generic / backport-5.10 / 785-v5.14-18-net-dsa-qca8k-dsa-qca8k-protect-MASTER-busy_wait-wit.patch

diff --git a/target/linux/generic/backport-5.10/785-v5.14-18-net-dsa-qca8k-dsa-qca8k-protect-MASTER-busy_wait-wit.patch b/target/linux/generic/backport-5.10/785-v5.14-18-net-dsa-qca8k-dsa-qca8k-protect-MASTER-busy_wait-wit.patch
new file mode 100644 (file)
index 0000000..b6684d7
--- /dev/null
+++ b/target/linux/generic/backport-5.10/785-v5.14-18-net-dsa-qca8k-dsa-qca8k-protect-MASTER-busy_wait-wit.patch
@@ -0,0 +1,128 @@
+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);