[v6,0/3] Three changes related with UFS clock scaling

Message

Can Guo Dec. 20, 2020, 5:42 a.m. UTC

This series is made based on 5.10/scsi-fixes branch.

Current devfreq framework allows sysfs nodes like governor, min_freq and max_freq to be changed even after devfreq device is suspended.
Meanwhile, devfreq_suspend_device() cannot/wouldn't synchronize ongoing execution invoked through sysfs nodes menitioned above either.
It means that UFS clock scaling can be invoked at any time (clkscale_enable is same) regardless of the state of UFS host and/or device.

The 1st change allows contexts to prevent clock scaling from being invoked through sysfs nodes like clkscale_enable.
The 2nd change is just a minor code cleanup.
The 3rd change reverts one old change which can be covered by the 1st change. For branches which do not have this change yet, it can be ignored.

Change since v5:
- Reomved the code change in ufshcd_shutdown() since it is not quite relevant with this fix

Change since v4:
- Updated some comment lines as requested by Stanley

Change since v3:
- Slightly updated the 1st change

Change since v2:
- Split the 1st change to two changes, which become the 1st change and the 3rd change

Change since v1:
- Updated the 2nd change


Can Guo (3):
  scsi: ufs: Protect some contexts from unexpected clock scaling
  scsi: ufs: Clean up ufshcd_exit_clk_scaling/gating()
  scsi: ufs: Revert "Make sure clk scaling happens only when HBA is
    runtime ACTIVE"

 drivers/scsi/ufs/ufshcd.c | 118 ++++++++++++++++++++++++++--------------------
 drivers/scsi/ufs/ufshcd.h |  10 +++-
 2 files changed, 76 insertions(+), 52 deletions(-)