Commit 3bc05faf authored by Vladimir Oltean's avatar Vladimir Oltean Committed by David S. Miller
Browse files

net: dsa: microchip: properly support platform_data probing 

The ksz driver has bits and pieces of platform_data probing support, but
it doesn't work.

The conventional thing to do is to have an encapsulating structure for
struct dsa_chip_data that gets put into dev->platform_data. This driver
expects a struct ksz_platform_data, but that doesn't contain a struct
dsa_chip_data as first element, which will obviously not work with
dsa_switch_probe() -> dsa_switch_parse().

Pointing dev->platform_data to a struct dsa_chip_data directly is in
principle possible, but that doesn't work either. The driver has
ksz_switch_detect() to read the device ID from hardware, followed by
ksz_check_device_id() to compare it against a predetermined expected
value. This protects against early errors in the SPI/I2C communication.
With platform_data, the mechanism in ksz_check_device_id() doesn't work
and even leads to NULL pointer dereferences, since of_device_get_match_data()
doesn't work in that probe path.

So obviously, the platform_data support is actually missing, and the
existing handling of struct ksz_platform_data is bogus. Complete the
support by adding a struct dsa_chip_data as first element, and fixing up
ksz_check_device_id() to pick up the platform_data instead of the
unavailable of_device_get_match_data().

The early dev->chip_id assignment from ksz_switch_register() is also
bogus, because ksz_switch_detect() sets it to an initial value. So
remove it.

Also, ksz_platform_data :: enabled_ports isn't used anywhere, delete it.

Link: https://lore.kernel.org/netdev/20231204154315.3906267-1-dd@embedd.com/


Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarDaniel Danzberger <dd@embedd.com>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d5449d59

drivers/net/dsa/microchip/ksz_common.c

+13 −8
Original line number Diff line number Diff line
@@ -1673,15 +1673,23 @@ static const struct ksz_chip_data *ksz_lookup_info(unsigned int prod_num) 


static int ksz_check_device_id(struct ksz_device *dev)

{

	const struct ksz_chip_data *dt_chip_data;

	const struct ksz_chip_data *expected_chip_data;

	u32 expected_chip_id;



	dt_chip_data = of_device_get_match_data(dev->dev);

	if (dev->pdata) {

		expected_chip_id = dev->pdata->chip_id;

		expected_chip_data = ksz_lookup_info(expected_chip_id);

		if (WARN_ON(!expected_chip_data))

			return -ENODEV;

	} else {

		expected_chip_data = of_device_get_match_data(dev->dev);

		expected_chip_id = expected_chip_data->chip_id;

	}



	/* Check for Device Tree and Chip ID */

	if (dt_chip_data->chip_id != dev->chip_id) {

	if (expected_chip_id != dev->chip_id) {

		dev_err(dev->dev,

			"Device tree specifies chip %s but found %s, please fix it!\n",

			dt_chip_data->dev_name, dev->info->dev_name);

			expected_chip_data->dev_name, dev->info->dev_name);

		return -ENODEV;

	}
@@ -4156,9 +4164,6 @@ int ksz_switch_register(struct ksz_device *dev) 
	int ret;

	int i;



	if (dev->pdata)

		dev->chip_id = dev->pdata->chip_id;



	dev->reset_gpio = devm_gpiod_get_optional(dev->dev, "reset",

						  GPIOD_OUT_LOW);

	if (IS_ERR(dev->reset_gpio))

include/linux/platform_data/microchip-ksz.h

+3 −1
Original line number Diff line number Diff line
@@ -20,10 +20,12 @@ 
#define __MICROCHIP_KSZ_H



#include <linux/types.h>

#include <linux/platform_data/dsa.h>



struct ksz_platform_data {

	/* Must be first such that dsa_register_switch() can access it */

	struct dsa_chip_data cd;

	u32 chip_id;

	u16 enabled_ports;

};



#endif