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Use proper caution when opening attachments, clicking links, or responding. > > > On 5/15/26 06:45, Akshay Gupta wrote: >> From: Prathima >> >> Implement IOCTL interface for SB-TSI driver to enable userspace access >> to TSI register read/write operations through the AMD Advanced Platform >> Management Link (APML) protocol. >> Add an ioctl command (SBTSI_IOCTL_REG_XFER_CMD) that accepts a register >> address, data byte, and direction flag. Serialize access with a mutex >> shared between the hwmon and ioctl paths to prevent concurrent bus >> transactions from corrupting register state. >> >> Reviewed-by: Akshay Gupta >> Signed-off-by: Prathima >> --- >> Changes since v1: >> - Use of devm_mutex_init in place of mutex_init >> - Use of guard_mutex in place of mutex_lock()/mutex_unlock() >> - Use of devm_add_action_or_reset() for clean removal >> >> drivers/hwmon/sbtsi_temp.c | 6 +++ >> drivers/misc/amd-sbi/tsi-core.c | 84 ++++++++++++++++++++++++++++++++- >> drivers/misc/amd-sbi/tsi-core.h | 15 ++++++ >> drivers/misc/amd-sbi/tsi.c | 20 ++++++-- >> include/linux/misc/tsi.h | 8 ++++ >> include/uapi/misc/amd-apml.h | 23 +++++++++ >> 6 files changed, 151 insertions(+), 5 deletions(-) >> create mode 100644 drivers/misc/amd-sbi/tsi-core.h >> >> diff --git a/drivers/hwmon/sbtsi_temp.c b/drivers/hwmon/sbtsi_temp.c >> index d7ae986d824c..00e982f4c716 100644 >> --- a/drivers/hwmon/sbtsi_temp.c >> +++ b/drivers/hwmon/sbtsi_temp.c >> @@ -64,12 +64,15 @@ static inline void sbtsi_mc_to_reg(s32 temp, u8 *integer, u8 *decimal) >> /* >> * Read integer and decimal parts of an SB-TSI temperature register pair >> * The read order is determined by the ReadOrder bit to ensure atomic latching. >> + * The mutex protects against concurrent access to the shared I2C/I3C bus by >> + * the hwmon sysfs and a userspace ioctl >> */ >> static int sbtsi_temp_read(struct sbtsi_data *data, u8 reg1, u8 reg2, >> u8 *val1, u8 *val2) >> { >> int ret; >> >> + guard(mutex)(&data->lock); > I would suggest to hide this behind access functions such as sbtsi_lock(), > sbtsi_unlock(), and the matching guard functions. That can be done in a > separate patch; it should not be necessary to include hwmon in the patch > introducing the ioctl. > > Thanks, > Guenter Thank you for the feedback, Guenter. In the next version, we will address this by implementing the matching guard function in the ioctl patch and creating a new patch for hwmon. >