1be49ae16f
commit 8eecddfca30e1651dc1c74531ed5eef21dcce7e3 upstream. In ufs_qcom_dev_ref_clk_ctrl(), it was noted that the ref_clk needs to be stable for at least 1us. Even though there is wmb() to make sure the write gets "completed", there is no guarantee that the write actually reached the UFS device. There is a good chance that the write could be stored in a Write Buffer (WB). In that case, even though the CPU waits for 1us, the ref_clk might not be stable for that period. So lets do a readl() to make sure that the previous write has reached the UFS device before udelay(). Also, the wmb() after writel_relaxed() is not really needed. Both writel() and readl() are ordered on all architectures and the CPU won't speculate instructions after readl() due to the in-built control dependency with read value on weakly ordered architectures. So it can be safely removed. Link: https://lore.kernel.org/r/20220504084212.11605-4-manivannan.sadhasivam@linaro.org Fixes: f06fcc7155dc ("scsi: ufs-qcom: add QUniPro hardware support and power optimizations") Cc: stable@vger.kernel.org Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.