Commit Graph

6 Commits

Author SHA1 Message Date
Thomas Weißschuh
3023c050af hwmon: (powerz) Avoid cacheline sharing for DMA buffer
Depending on the architecture the transfer buffer may share a cacheline
with the following mutex. As the buffer may be used for DMA, that is
problematic.

Use the high-level DMA helpers to make sure that cacheline sharing can
not happen.

Also drop the comment, as the helpers are documentation enough.

https://sashiko.dev/#/message/20260408175814.934BFC19421%40smtp.kernel.org

Fixes: 4381a36abd ("hwmon: add POWER-Z driver")
Cc: stable@vger.kernel.org # ca085faabb42: dma-mapping: add __dma_from_device_group_begin()/end()
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20260408-powerz-cacheline-alias-v1-1-1254891be0dd@weissschuh.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2026-04-10 08:33:08 -07:00
Sanman Pradhan
b66437cb20 hwmon: (powerz) Fix missing usb_kill_urb() on signal interrupt
wait_for_completion_interruptible_timeout() returns -ERESTARTSYS when
interrupted. This needs to abort the URB and return an error. No data
has been received from the device so any reads from the transfer
buffer are invalid.

The original code tests !ret, which only catches the timeout case (0).
On signal delivery (-ERESTARTSYS), !ret is false so the function skips
usb_kill_urb() and falls through to read from the unfilled transfer
buffer.

Fix by capturing the return value into a long (matching the function
return type) and handling signal (negative) and timeout (zero) cases
with separate checks that both call usb_kill_urb() before returning.

Fixes: 4381a36abd ("hwmon: add POWER-Z driver")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Link: https://lore.kernel.org/r/20260410002521.422645-3-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2026-04-10 08:29:27 -07:00
Sanman Pradhan
08e57f5e1a hwmon: (powerz) Fix use-after-free on USB disconnect
After powerz_disconnect() frees the URB and releases the mutex, a
subsequent powerz_read() call can acquire the mutex and call
powerz_read_data(), which dereferences the freed URB pointer.

Fix by:
 - Setting priv->urb to NULL in powerz_disconnect() so that
   powerz_read_data() can detect the disconnected state.
 - Adding a !priv->urb check at the start of powerz_read_data()
   to return -ENODEV on a disconnected device.
 - Moving usb_set_intfdata() before hwmon registration so the
   disconnect handler can always find the priv pointer.

Fixes: 4381a36abd ("hwmon: add POWER-Z driver")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Link: https://lore.kernel.org/r/20260410002521.422645-2-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2026-04-10 08:28:18 -07:00
Heiner Kallweit
1d92c936ca hwmon: (powerz) Simplify specifying static visibility attribute
Use new member visible of struct hwmon_ops to simplify specifying
the static attribute visibility.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Thomas Weißschuh <linux@weissschuh.net>
Message-ID: <c4b4568b-59f6-43ac-8281-536a82ecd6ab@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-11-10 14:48:06 -08:00
Thomas Weißschuh
2232f10d71 hwmon: (powerz) add support for ChargerLAB KM002C
The KM002C is similar to the KM003C and seems to use the same
protocol and firmware.

Reported-by: Douglas Gilbert <dgilbert@interlog.com>
Closes: https://lore.kernel.org/lkml/290ebce4-54f0-8ac1-2a13-cbc806d80d64@interlog.com/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230911-powerz-km002c-v1-1-898bd79b9bae@weissschuh.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-10-27 07:27:25 -07:00
Thomas Weißschuh
4381a36abd hwmon: add POWER-Z driver
POWER-Z is a series of devices to monitor power characteristics of
USB-C connections and display those on a on-device display.
Some of the devices, notably KM002C and KM003C, contain an additional
port which exposes the measurements via USB.

This is a driver for this monitor port.

It was developed and tested with the KM003C.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230902-powerz-v4-1-7ec2c1440687@weissschuh.net
[groeck:
 Release urb after hwmon registration error;
 Move priv->status initialization to correct place before reinit_completion
 ]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-10-27 07:27:23 -07:00