net: dsa: microchip: Add shared regmap mutex

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>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/microchip/ksz8795_spi.c b/drivers/net/dsa/microchip/ksz8795_spi.c
index d0f8153e86b7d7bddcde1cd30b305c4e6a69b5f5..8b00f8e6c02f4f2a2fbc545c026cb2daaa48528c 100644 (file)
--- a/drivers/net/dsa/microchip/ksz8795_spi.c
+++ b/drivers/net/dsa/microchip/ksz8795_spi.c
@@ -25,6 +25,7 @@ KSZ_REGMAP_TABLE(ksz8795, 16, SPI_ADDR_SHIFT,
 
 static int ksz8795_spi_probe(struct spi_device *spi)
 {
+       struct regmap_config rc;
        struct ksz_device *dev;
        int i, ret;
 
@@ -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 0b1e01f0873d5733336e3c291148f5993494f3c1..fdffd9e0c518b53d0f55e4bb1fe5975ddcebed58 100644 (file)
--- a/drivers/net/dsa/microchip/ksz9477_i2c.c
+++ b/drivers/net/dsa/microchip/ksz9477_i2c.c
@@ -17,6 +17,7 @@ KSZ_REGMAP_TABLE(ksz9477, not_used, 16, 0, 0);
 static int ksz9477_i2c_probe(struct i2c_client *i2c,
                             const struct i2c_device_id *i2c_id)
 {
+       struct regmap_config rc;
        struct ksz_device *dev;
        int i, ret;
 
@@ -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 f4198d6f72bee55a6ba4f0dca945f0d701870d82..c5f64959a184e25b25adc68f33543a6236b2f874 100644 (file)
--- a/drivers/net/dsa/microchip/ksz9477_spi.c
+++ b/drivers/net/dsa/microchip/ksz9477_spi.c
@@ -24,6 +24,7 @@ KSZ_REGMAP_TABLE(ksz9477, 32, SPI_ADDR_SHIFT,
 
 static int ksz9477_spi_probe(struct spi_device *spi)
 {
+       struct regmap_config rc;
        struct ksz_device *dev;
        int i, ret;
 
@@ -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 b0b870f0c252095f7844230b3e3fe700e14d75fe..fe47180c908b979fe9df3d40ee6729ca9d78828f 100644 (file)
--- 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 64c2677693d2d750f2ba55d4900bcea445dabb2a..a20ebb749377c1356506aabb1ded804d916d4a0e 100644 (file)
--- 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                  \
        }