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Subject[RFC PATCH 1/2] regmap: mdio: Clean up invalid clause-22 addresses
Date
Currently a regmap configuration for regmap-mdio must have a register
address width of 5 bits (cf. clause-22 register access). This is not
enforced on the provided register addresses, which would enable
clause-45 MDIO bus access, if the right bit packing is used.

Prevent clause-45 access, and other invalid addresses, by masking the
provided register address.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
---
drivers/base/regmap/regmap-mdio.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/base/regmap/regmap-mdio.c b/drivers/base/regmap/regmap-mdio.c
index 5ec208279913..aee34bf2400e 100644
--- a/drivers/base/regmap/regmap-mdio.c
+++ b/drivers/base/regmap/regmap-mdio.c
@@ -5,16 +5,19 @@
#include <linux/module.h>
#include <linux/regmap.h>

+#define REGVAL_MASK GENMASK(15, 0)
+#define REGNUM_C22_MASK GENMASK(4, 0)
+
static int regmap_mdio_read(void *context, unsigned int reg, unsigned int *val)
{
struct mdio_device *mdio_dev = context;
int ret;

- ret = mdiobus_read(mdio_dev->bus, mdio_dev->addr, reg);
+ ret = mdiobus_read(mdio_dev->bus, mdio_dev->addr, reg & REGNUM_C22_MASK);
if (ret < 0)
return ret;

- *val = ret & 0xffff;
+ *val = ret & REGVAL_MASK;
return 0;
}

@@ -22,7 +25,7 @@ static int regmap_mdio_write(void *context, unsigned int reg, unsigned int val)
{
struct mdio_device *mdio_dev = context;

- return mdiobus_write(mdio_dev->bus, mdio_dev->addr, reg, val);
+ return mdiobus_write(mdio_dev->bus, mdio_dev->addr, reg & REGNUM_C22_MASK, val);
}

static const struct regmap_bus regmap_mdio_bus = {
--
2.31.1
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