scsi: ufs: Protect some contexts from unexpected clock scaling
In contexts like suspend, shutdown, and error handling we need to suspend devfreq to make sure these contexts won't be disturbed by clock scaling. However, suspending devfreq is not enough since users can still trigger a clock scaling by manipulating the devfreq sysfs nodes like min/max_freq and governor even after devfreq is suspended. Moreover, mere suspending devfreq cannot synchroinze a clock scaling which has already been invoked through these sysfs nodes. Add one more flag in struct clk_scaling and wrap the entire func ufshcd_devfreq_scale() with the clk_scaling_lock, so that we can use this flag and clk_scaling_lock to control and synchronize clock scaling invoked through devfreq sysfs nodes. Link: https://lore.kernel.org/r/1611137065-14266-2-git-send-email-cang@codeaurora.org Reviewed-by:Stanley Chu <stanley.chu@mediatek.com> Signed-off-by:
Can Guo <cang@codeaurora.org> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com>
parent
4cd48995
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