• Bjorn Andersson's avatar
    phy: qcom-qmp: Correct READY_STATUS poll break condition · 885bd765
    Bjorn Andersson authored
    After issuing a PHY_START request to the QMP, the hardware documentation
    states that the software should wait for the PCS_READY_STATUS to become
    1.
    
    With the introduction of commit c9b58979 ("phy: qcom: Utilize UFS
    reset controller") an additional 1ms delay was introduced between the
    start request and the check of the status bit. This greatly increases
    the chances for the hardware to actually becoming ready before the
    status bit is read.
    
    The result can be seen in that UFS PHY enabling is now reported as a
    failure in 10% of the boots on SDM845, which is a clear regression from
    the previous rare/occasional failure.
    
    This patch fixes the "break condition" of the poll to check for the
    correct state of the status bit.
    
    Unfortunately PCIe on 8996 and 8998 does not specify the mask_pcs_ready
    register, which means that the code checks a bit that's always 0. So the
    patch also fixes these, in order to not regress these targets.
    
    Fixes: 73d7ec89 ("phy: qcom-qmp: Add msm8998 PCIe QMP PHY support")
    Fixes: e78f3d15 ("phy: qcom-qmp: new qmp phy driver for qcom-chipsets")
    Cc: stable@vger.kernel.org
    Cc: Evan Green <evgreen@chromium.org>
    Cc: Marc Gonzalez <marc.w.gonzalez@free.fr>
    Cc: Vivek Gautam <vivek.gautam@codeaurora.org>
    Reviewed-by: default avatarEvan Green <evgreen@chromium.org>
    Reviewed-by: default avatarNiklas Cassel <niklas.cassel@linaro.org>
    Reviewed-by: default avatarMarc Gonzalez <marc.w.gonzalez@free.fr>
    Tested-by: default avatarMarc Gonzalez <marc.w.gonzalez@free.fr>
    Signed-off-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
    Signed-off-by: default avatarKishon Vijay Abraham I <kishon@ti.com>
    885bd765
phy-qcom-qmp.c 72.4 KB