[PATCH V2 1/2] net: dsa: microchip: Do not reinit mutexes on KSZ87xx

[PATCH V2 1/2] net: dsa: microchip: Do not reinit mutexes on KSZ87xx

[Marek Vasut]

The KSZ87xx driver calls mutex_init() on mutexes already inited in
ksz_common.c ksz_switch_register(). Do not do it twice, drop the
reinitialization.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: David S. Miller <davem@davemloft.net>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: George McCollister <george.mccollister@gmail.com>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Cc: Woojung Huh <woojung.huh@microchip.com>
---
V2: None
---
 drivers/net/dsa/microchip/ksz8795.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz8795.c b/drivers/net/dsa/microchip/ksz8795.c
index a23d3ffdf0c4..24a5e99f7fd5 100644
--- a/drivers/net/dsa/microchip/ksz8795.c
+++ b/drivers/net/dsa/microchip/ksz8795.c
@@ -1224,10 +1224,6 @@ static int ksz8795_switch_init(struct ksz_device *dev)
 {
 	int i;
 
-	mutex_init(&dev->stats_mutex);
-	mutex_init(&dev->alu_mutex);
-	mutex_init(&dev->vlan_mutex);
-
 	dev->ds->ops = &ksz8795_switch_ops;
 
 	for (i = 0; i < ARRAY_SIZE(ksz8795_switch_chips); i++) {
-- 
2.23.0

[PATCH V2 2/2] net: dsa: microchip: Add shared regmap mutex

[Marek Vasut]

The KSZ driver uses one regmap per register width (8/16/32), each with
it's own lock, but accessing the same set of registers. In theory, it
is possible to create a race condition between these regmaps, although
the underlying bus (SPI or I2C) locking should assure nothing bad will
really happen and the accesses would be correct.

To make the driver do the right thing, add one single shared mutex for
all the regmaps used by the driver instead. This assures that even if
some future hardware is on a bus which does not serialize the accesses
the same way SPI or I2C does, nothing bad will happen.

Note that the status_mutex was unused and only initied, hence it was
renamed and repurposed as the regmap mutex.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: David S. Miller <davem@davemloft.net>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: George McCollister <george.mccollister@gmail.com>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Cc: Woojung Huh <woojung.huh@microchip.com>
---
V2: Move ksz_regmap_{,un}lock() to ksz_common.h and turn it from void
    to static inline void. This fixes the following build failure:
    ERROR: "ksz_regmap_unlock" [drivers/net/dsa/microchip/ksz8795_spi.ko] undefined!
    ERROR: "ksz_regmap_lock" [drivers/net/dsa/microchip/ksz8795_spi.ko] undefined!
    ERROR: "ksz_regmap_unlock" [drivers/net/dsa/microchip/ksz9477_spi.ko] undefined!
    ERROR: "ksz_regmap_lock" [drivers/net/dsa/microchip/ksz9477_spi.ko] undefined!
    ERROR: "ksz_regmap_unlock" [drivers/net/dsa/microchip/ksz9477_i2c.ko] undefined!
    ERROR: "ksz_regmap_lock" [drivers/net/dsa/microchip/ksz9477_i2c.ko] undefined!
---
 drivers/net/dsa/microchip/ksz8795_spi.c |  7 ++++---
 drivers/net/dsa/microchip/ksz9477_i2c.c |  6 ++++--
 drivers/net/dsa/microchip/ksz9477_spi.c |  6 ++++--
 drivers/net/dsa/microchip/ksz_common.c  |  2 +-
 drivers/net/dsa/microchip/ksz_common.h  | 16 +++++++++++++++-
 5 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz8795_spi.c b/drivers/net/dsa/microchip/ksz8795_spi.c
index d0f8153e86b7..614404c40cba 100644
--- a/drivers/net/dsa/microchip/ksz8795_spi.c
+++ b/drivers/net/dsa/microchip/ksz8795_spi.c
@@ -26,6 +26,7 @@ KSZ_REGMAP_TABLE(ksz8795, 16, SPI_ADDR_SHIFT,
 static int ksz8795_spi_probe(struct spi_device *spi)
 {
 	struct ksz_device *dev;
+	struct regmap_config rc;
 	int i, ret;
 
 	dev = ksz_switch_alloc(&spi->dev, spi);
@@ -33,9 +34,9 @@ static int ksz8795_spi_probe(struct spi_device *spi)
 		return -ENOMEM;
 
 	for (i = 0; i < ARRAY_SIZE(ksz8795_regmap_config); i++) {
-		dev->regmap[i] = devm_regmap_init_spi(spi,
-						      &ksz8795_regmap_config
-						      [i]);
+		rc = ksz8795_regmap_config[i];
+		rc.lock_arg = &dev->regmap_mutex;
+		dev->regmap[i] = devm_regmap_init_spi(spi, &rc);
 		if (IS_ERR(dev->regmap[i])) {
 			ret = PTR_ERR(dev->regmap[i]);
 			dev_err(&spi->dev,
diff --git a/drivers/net/dsa/microchip/ksz9477_i2c.c b/drivers/net/dsa/microchip/ksz9477_i2c.c
index b0a1595d780d..2cb178675b83 100644
--- a/drivers/net/dsa/microchip/ksz9477_i2c.c
+++ b/drivers/net/dsa/microchip/ksz9477_i2c.c
@@ -18,6 +18,7 @@ static int ksz9477_i2c_probe(struct i2c_client *i2c,
 			     const struct i2c_device_id *i2c_id)
 {
 	struct ksz_device *dev;
+	struct regmap_config rc;
 	int i, ret;
 
 	dev = ksz_switch_alloc(&i2c->dev, i2c);
@@ -25,8 +26,9 @@ static int ksz9477_i2c_probe(struct i2c_client *i2c,
 		return -ENOMEM;
 
 	for (i = 0; i < ARRAY_SIZE(ksz9477_regmap_config); i++) {
-		dev->regmap[i] = devm_regmap_init_i2c(i2c,
-					&ksz9477_regmap_config[i]);
+		rc = ksz9477_regmap_config[i];
+		rc.lock_arg = &dev->regmap_mutex;
+		dev->regmap[i] = devm_regmap_init_i2c(i2c, &rc);
 		if (IS_ERR(dev->regmap[i])) {
 			ret = PTR_ERR(dev->regmap[i]);
 			dev_err(&i2c->dev,
diff --git a/drivers/net/dsa/microchip/ksz9477_spi.c b/drivers/net/dsa/microchip/ksz9477_spi.c
index f4198d6f72be..a39d2373eb3a 100644
--- a/drivers/net/dsa/microchip/ksz9477_spi.c
+++ b/drivers/net/dsa/microchip/ksz9477_spi.c
@@ -25,6 +25,7 @@ KSZ_REGMAP_TABLE(ksz9477, 32, SPI_ADDR_SHIFT,
 static int ksz9477_spi_probe(struct spi_device *spi)
 {
 	struct ksz_device *dev;
+	struct regmap_config rc;
 	int i, ret;
 
 	dev = ksz_switch_alloc(&spi->dev, spi);
@@ -32,8 +33,9 @@ static int ksz9477_spi_probe(struct spi_device *spi)
 		return -ENOMEM;
 
 	for (i = 0; i < ARRAY_SIZE(ksz9477_regmap_config); i++) {
-		dev->regmap[i] = devm_regmap_init_spi(spi,
-					&ksz9477_regmap_config[i]);
+		rc = ksz9477_regmap_config[i];
+		rc.lock_arg = &dev->regmap_mutex;
+		dev->regmap[i] = devm_regmap_init_spi(spi, &rc);
 		if (IS_ERR(dev->regmap[i])) {
 			ret = PTR_ERR(dev->regmap[i]);
 			dev_err(&spi->dev,
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index b0b870f0c252..fe47180c908b 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -436,7 +436,7 @@ int ksz_switch_register(struct ksz_device *dev,
 	}
 
 	mutex_init(&dev->dev_mutex);
-	mutex_init(&dev->stats_mutex);
+	mutex_init(&dev->regmap_mutex);
 	mutex_init(&dev->alu_mutex);
 	mutex_init(&dev->vlan_mutex);
 
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index dd60d0837fc6..d78e61114765 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -47,7 +47,7 @@ struct ksz_device {
 	const char *name;
 
 	struct mutex dev_mutex;		/* device access */
-	struct mutex stats_mutex;	/* status access */
+	struct mutex regmap_mutex;	/* regmap access */
 	struct mutex alu_mutex;		/* ALU access */
 	struct mutex vlan_mutex;	/* vlan access */
 	const struct ksz_dev_ops *dev_ops;
@@ -290,6 +290,18 @@ static inline void ksz_pwrite32(struct ksz_device *dev, int port, int offset,
 	ksz_write32(dev, dev->dev_ops->get_port_addr(port, offset), data);
 }
 
+static inline void ksz_regmap_lock(void *__mtx)
+{
+	struct mutex *mtx = __mtx;
+	mutex_lock(mtx);
+}
+
+static inline void ksz_regmap_unlock(void *__mtx)
+{
+	struct mutex *mtx = __mtx;
+	mutex_unlock(mtx);
+}
+
 /* Regmap tables generation */
 #define KSZ_SPI_OP_RD		3
 #define KSZ_SPI_OP_WR		2
@@ -314,6 +326,8 @@ static inline void ksz_pwrite32(struct ksz_device *dev, int port, int offset,
 		.write_flag_mask =					\
 			KSZ_SPI_OP_FLAG_MASK(KSZ_SPI_OP_WR, swp,	\
 					     regbits, regpad),		\
+		.lock = ksz_regmap_lock,				\
+		.unlock = ksz_regmap_unlock,				\
 		.reg_format_endian = REGMAP_ENDIAN_BIG,			\
 		.val_format_endian = REGMAP_ENDIAN_BIG			\
 	}
-- 
2.23.0

Re: [PATCH V2 2/2] net: dsa: microchip: Add shared regmap mutex

[David Miller]

From: Marek Vasut <marex@denx.de>
Date: Sun, 13 Oct 2019 21:32:38 +0200

> diff --git a/drivers/net/dsa/microchip/ksz8795_spi.c b/drivers/net/dsa/microchip/ksz8795_spi.c
> index d0f8153e86b7..614404c40cba 100644
> --- a/drivers/net/dsa/microchip/ksz8795_spi.c
> +++ b/drivers/net/dsa/microchip/ksz8795_spi.c
> @@ -26,6 +26,7 @@ KSZ_REGMAP_TABLE(ksz8795, 16, SPI_ADDR_SHIFT,
>  static int ksz8795_spi_probe(struct spi_device *spi)
>  {
>  	struct ksz_device *dev;
> +	struct regmap_config rc;
>  	int i, ret;

Please retain the reverse christmas tree ordering of local variables
here.

> @@ -18,6 +18,7 @@ static int ksz9477_i2c_probe(struct i2c_client *i2c,
>  			     const struct i2c_device_id *i2c_id)
>  {
>  	struct ksz_device *dev;
> +	struct regmap_config rc;
>  	int i, ret;

Likewise.

> @@ -25,6 +25,7 @@ KSZ_REGMAP_TABLE(ksz9477, 32, SPI_ADDR_SHIFT,
>  static int ksz9477_spi_probe(struct spi_device *spi)
>  {
>  	struct ksz_device *dev;
> +	struct regmap_config rc;
>  	int i, ret;

Likewise.

Re: [PATCH V2 1/2] net: dsa: microchip: Do not reinit mutexes on KSZ87xx

[Andrew Lunn]

On Sun, Oct 13, 2019 at 09:32:37PM +0200, Marek Vasut wrote:
> The KSZ87xx driver calls mutex_init() on mutexes already inited in
> ksz_common.c ksz_switch_register(). Do not do it twice, drop the
> reinitialization.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH V2 2/2] net: dsa: microchip: Add shared regmap mutex

[Andrew Lunn]

On Sun, Oct 13, 2019 at 09:32:38PM +0200, Marek Vasut wrote:
> The KSZ driver uses one regmap per register width (8/16/32), each with
> it's own lock, but accessing the same set of registers. In theory, it
> is possible to create a race condition between these regmaps, although
> the underlying bus (SPI or I2C) locking should assure nothing bad will
> really happen and the accesses would be correct.
> 
> To make the driver do the right thing, add one single shared mutex for
> all the regmaps used by the driver instead. This assures that even if
> some future hardware is on a bus which does not serialize the accesses
> the same way SPI or I2C does, nothing bad will happen.
> 
> Note that the status_mutex was unused and only initied, hence it was
> renamed and repurposed as the regmap mutex.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>

Apart from the reverse Christmas tree:

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew