Merge branch 'dsa-realtek-phy-read-corruption'

Alvin Šipraga says:

====================
net: dsa: realtek: fix PHY register read corruption

These two patches fix the issue reported by Arınç where PHY register
reads sometimes return garbage data.

v1 -> v2:

- no code changes
- just update the commit message of patch 2 to reflect the conclusion
  of further investigation requested by Vladimir
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 124 insertions, 26 deletions

diff --git a/drivers/net/dsa/realtek/realtek-mdio.c b/drivers/net/dsa/realtek/realtek-mdio.c
index 0308be95d00a..31e1f100e48e 100644
--- a/drivers/net/dsa/realtek/realtek-mdio.c
+++ b/drivers/net/dsa/realtek/realtek-mdio.c
@@ -98,6 +98,20 @@ out_unlock:
 	return ret;
 }
 
+static void realtek_mdio_lock(void *ctx)
+{
+	struct realtek_priv *priv = ctx;
+
+	mutex_lock(&priv->map_lock);
+}
+
+static void realtek_mdio_unlock(void *ctx)
+{
+	struct realtek_priv *priv = ctx;
+
+	mutex_unlock(&priv->map_lock);
+}
+
 static const struct regmap_config realtek_mdio_regmap_config = {
 	.reg_bits = 10, /* A4..A0 R4..R0 */
 	.val_bits = 16,
@@ -108,6 +122,21 @@ static const struct regmap_config realtek_mdio_regmap_config = {
 	.reg_read = realtek_mdio_read,
 	.reg_write = realtek_mdio_write,
 	.cache_type = REGCACHE_NONE,
+	.lock = realtek_mdio_lock,
+	.unlock = realtek_mdio_unlock,
+};
+
+static const struct regmap_config realtek_mdio_nolock_regmap_config = {
+	.reg_bits = 10, /* A4..A0 R4..R0 */
+	.val_bits = 16,
+	.reg_stride = 1,
+	/* PHY regs are at 0x8000 */
+	.max_register = 0xffff,
+	.reg_format_endian = REGMAP_ENDIAN_BIG,
+	.reg_read = realtek_mdio_read,
+	.reg_write = realtek_mdio_write,
+	.cache_type = REGCACHE_NONE,
+	.disable_locking = true,
 };
 
 static int realtek_mdio_probe(struct mdio_device *mdiodev)
@@ -115,8 +144,9 @@ static int realtek_mdio_probe(struct mdio_device *mdiodev)
 	struct realtek_priv *priv;
 	struct device *dev = &mdiodev->dev;
 	const struct realtek_variant *var;
-	int ret;
+	struct regmap_config rc;
 	struct device_node *np;
+	int ret;
 
 	var = of_device_get_match_data(dev);
 	if (!var)
@@ -126,13 +156,25 @@ static int realtek_mdio_probe(struct mdio_device *mdiodev)
 	if (!priv)
 		return -ENOMEM;
 
-	priv->map = devm_regmap_init(dev, NULL, priv, &realtek_mdio_regmap_config);
+	mutex_init(&priv->map_lock);
+
+	rc = realtek_mdio_regmap_config;
+	rc.lock_arg = priv;
+	priv->map = devm_regmap_init(dev, NULL, priv, &rc);
 	if (IS_ERR(priv->map)) {
 		ret = PTR_ERR(priv->map);
 		dev_err(dev, "regmap init failed: %d\n", ret);
 		return ret;
 	}
 
+	rc = realtek_mdio_nolock_regmap_config;
+	priv->map_nolock = devm_regmap_init(dev, NULL, priv, &rc);
+	if (IS_ERR(priv->map_nolock)) {
+		ret = PTR_ERR(priv->map_nolock);
+		dev_err(dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
 	priv->mdio_addr = mdiodev->addr;
 	priv->bus = mdiodev->bus;
 	priv->dev = &mdiodev->dev;
diff --git a/drivers/net/dsa/realtek/realtek-smi.c b/drivers/net/dsa/realtek/realtek-smi.c
index 8806b74bd7a8..2243d3da55b2 100644
--- a/drivers/net/dsa/realtek/realtek-smi.c
+++ b/drivers/net/dsa/realtek/realtek-smi.c
@@ -311,7 +311,21 @@ static int realtek_smi_read(void *ctx, u32 reg, u32 *val)
 	return realtek_smi_read_reg(priv, reg, val);
 }
 
-static const struct regmap_config realtek_smi_mdio_regmap_config = {
+static void realtek_smi_lock(void *ctx)
+{
+	struct realtek_priv *priv = ctx;
+
+	mutex_lock(&priv->map_lock);
+}
+
+static void realtek_smi_unlock(void *ctx)
+{
+	struct realtek_priv *priv = ctx;
+
+	mutex_unlock(&priv->map_lock);
+}
+
+static const struct regmap_config realtek_smi_regmap_config = {
 	.reg_bits = 10, /* A4..A0 R4..R0 */
 	.val_bits = 16,
 	.reg_stride = 1,
@@ -321,6 +335,21 @@ static const struct regmap_config realtek_smi_mdio_regmap_config = {
 	.reg_read = realtek_smi_read,
 	.reg_write = realtek_smi_write,
 	.cache_type = REGCACHE_NONE,
+	.lock = realtek_smi_lock,
+	.unlock = realtek_smi_unlock,
+};
+
+static const struct regmap_config realtek_smi_nolock_regmap_config = {
+	.reg_bits = 10, /* A4..A0 R4..R0 */
+	.val_bits = 16,
+	.reg_stride = 1,
+	/* PHY regs are at 0x8000 */
+	.max_register = 0xffff,
+	.reg_format_endian = REGMAP_ENDIAN_BIG,
+	.reg_read = realtek_smi_read,
+	.reg_write = realtek_smi_write,
+	.cache_type = REGCACHE_NONE,
+	.disable_locking = true,
 };
 
 static int realtek_smi_mdio_read(struct mii_bus *bus, int addr, int regnum)
@@ -385,6 +414,7 @@ static int realtek_smi_probe(struct platform_device *pdev)
 	const struct realtek_variant *var;
 	struct device *dev = &pdev->dev;
 	struct realtek_priv *priv;
+	struct regmap_config rc;
 	struct device_node *np;
 	int ret;
 
@@ -395,14 +425,26 @@ static int realtek_smi_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 	priv->chip_data = (void *)priv + sizeof(*priv);
-	priv->map = devm_regmap_init(dev, NULL, priv,
-				     &realtek_smi_mdio_regmap_config);
+
+	mutex_init(&priv->map_lock);
+
+	rc = realtek_smi_regmap_config;
+	rc.lock_arg = priv;
+	priv->map = devm_regmap_init(dev, NULL, priv, &rc);
 	if (IS_ERR(priv->map)) {
 		ret = PTR_ERR(priv->map);
 		dev_err(dev, "regmap init failed: %d\n", ret);
 		return ret;
 	}
 
+	rc = realtek_smi_nolock_regmap_config;
+	priv->map_nolock = devm_regmap_init(dev, NULL, priv, &rc);
+	if (IS_ERR(priv->map_nolock)) {
+		ret = PTR_ERR(priv->map_nolock);
+		dev_err(dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
 	/* Link forward and backward */
 	priv->dev = dev;
 	priv->clk_delay = var->clk_delay;
diff --git a/drivers/net/dsa/realtek/realtek.h b/drivers/net/dsa/realtek/realtek.h
index e7d3e1bcf8b8..4fa7c6ba874a 100644
--- a/drivers/net/dsa/realtek/realtek.h
+++ b/drivers/net/dsa/realtek/realtek.h
@@ -52,6 +52,8 @@ struct realtek_priv {
 	struct gpio_desc	*mdc;
 	struct gpio_desc	*mdio;
 	struct regmap		*map;
+	struct regmap		*map_nolock;
+	struct mutex		map_lock;
 	struct mii_bus		*slave_mii_bus;
 	struct mii_bus		*bus;
 	int			mdio_addr;
diff --git a/drivers/net/dsa/realtek/rtl8365mb.c b/drivers/net/dsa/realtek/rtl8365mb.c
index 2ed592147c20..c39d6b744597 100644
--- a/drivers/net/dsa/realtek/rtl8365mb.c
+++ b/drivers/net/dsa/realtek/rtl8365mb.c
@@ -590,7 +590,7 @@ static int rtl8365mb_phy_poll_busy(struct realtek_priv *priv)
 {
 	u32 val;
 
-	return regmap_read_poll_timeout(priv->map,
+	return regmap_read_poll_timeout(priv->map_nolock,
 					RTL8365MB_INDIRECT_ACCESS_STATUS_REG,
 					val, !val, 10, 100);
 }
@@ -604,7 +604,7 @@ static int rtl8365mb_phy_ocp_prepare(struct realtek_priv *priv, int phy,
 	/* Set OCP prefix */
 	val = FIELD_GET(RTL8365MB_PHY_OCP_ADDR_PREFIX_MASK, ocp_addr);
 	ret = regmap_update_bits(
-		priv->map, RTL8365MB_GPHY_OCP_MSB_0_REG,
+		priv->map_nolock, RTL8365MB_GPHY_OCP_MSB_0_REG,
 		RTL8365MB_GPHY_OCP_MSB_0_CFG_CPU_OCPADR_MASK,
 		FIELD_PREP(RTL8365MB_GPHY_OCP_MSB_0_CFG_CPU_OCPADR_MASK, val));
 	if (ret)
@@ -617,8 +617,8 @@ static int rtl8365mb_phy_ocp_prepare(struct realtek_priv *priv, int phy,
 			  ocp_addr >> 1);
 	val |= FIELD_PREP(RTL8365MB_INDIRECT_ACCESS_ADDRESS_OCPADR_9_6_MASK,
 			  ocp_addr >> 6);
-	ret = regmap_write(priv->map, RTL8365MB_INDIRECT_ACCESS_ADDRESS_REG,
-			   val);
+	ret = regmap_write(priv->map_nolock,
+			   RTL8365MB_INDIRECT_ACCESS_ADDRESS_REG, val);
 	if (ret)
 		return ret;
 
@@ -631,36 +631,42 @@ static int rtl8365mb_phy_ocp_read(struct realtek_priv *priv, int phy,
 	u32 val;
 	int ret;
 
+	mutex_lock(&priv->map_lock);
+
 	ret = rtl8365mb_phy_poll_busy(priv);
 	if (ret)
-		return ret;
+		goto out;
 
 	ret = rtl8365mb_phy_ocp_prepare(priv, phy, ocp_addr);
 	if (ret)
-		return ret;
+		goto out;
 
 	/* Execute read operation */
 	val = FIELD_PREP(RTL8365MB_INDIRECT_ACCESS_CTRL_CMD_MASK,
 			 RTL8365MB_INDIRECT_ACCESS_CTRL_CMD_VALUE) |
 	      FIELD_PREP(RTL8365MB_INDIRECT_ACCESS_CTRL_RW_MASK,
 			 RTL8365MB_INDIRECT_ACCESS_CTRL_RW_READ);
-	ret = regmap_write(priv->map, RTL8365MB_INDIRECT_ACCESS_CTRL_REG, val);
+	ret = regmap_write(priv->map_nolock, RTL8365MB_INDIRECT_ACCESS_CTRL_REG,
+			   val);
 	if (ret)
-		return ret;
+		goto out;
 
 	ret = rtl8365mb_phy_poll_busy(priv);
 	if (ret)
-		return ret;
+		goto out;
 
 	/* Get PHY register data */
-	ret = regmap_read(priv->map, RTL8365MB_INDIRECT_ACCESS_READ_DATA_REG,
-			  &val);
+	ret = regmap_read(priv->map_nolock,
+			  RTL8365MB_INDIRECT_ACCESS_READ_DATA_REG, &val);
 	if (ret)
-		return ret;
+		goto out;
 
 	*data = val & 0xFFFF;
 
-	return 0;
+out:
+	mutex_unlock(&priv->map_lock);
+
+	return ret;
 }
 
 static int rtl8365mb_phy_ocp_write(struct realtek_priv *priv, int phy,
@@ -669,32 +675,38 @@ static int rtl8365mb_phy_ocp_write(struct realtek_priv *priv, int phy,
 	u32 val;
 	int ret;
 
+	mutex_lock(&priv->map_lock);
+
 	ret = rtl8365mb_phy_poll_busy(priv);
 	if (ret)
-		return ret;
+		goto out;
 
 	ret = rtl8365mb_phy_ocp_prepare(priv, phy, ocp_addr);
 	if (ret)
-		return ret;
+		goto out;
 
 	/* Set PHY register data */
-	ret = regmap_write(priv->map, RTL8365MB_INDIRECT_ACCESS_WRITE_DATA_REG,
-			   data);
+	ret = regmap_write(priv->map_nolock,
+			   RTL8365MB_INDIRECT_ACCESS_WRITE_DATA_REG, data);
 	if (ret)
-		return ret;
+		goto out;
 
 	/* Execute write operation */
 	val = FIELD_PREP(RTL8365MB_INDIRECT_ACCESS_CTRL_CMD_MASK,
 			 RTL8365MB_INDIRECT_ACCESS_CTRL_CMD_VALUE) |
 	      FIELD_PREP(RTL8365MB_INDIRECT_ACCESS_CTRL_RW_MASK,
 			 RTL8365MB_INDIRECT_ACCESS_CTRL_RW_WRITE);
-	ret = regmap_write(priv->map, RTL8365MB_INDIRECT_ACCESS_CTRL_REG, val);
+	ret = regmap_write(priv->map_nolock, RTL8365MB_INDIRECT_ACCESS_CTRL_REG,
+			   val);
 	if (ret)
-		return ret;
+		goto out;
 
 	ret = rtl8365mb_phy_poll_busy(priv);
 	if (ret)
-		return ret;
+		goto out;
+
+out:
+	mutex_unlock(&priv->map_lock);
 
 	return 0;
 }