scsi: ufs: qcom: Update PHY settings only when scaling to higher gears

The "hs_gear" variable is used to program the PHY settings (submode) during
ufs_qcom_power_up_sequence(). Currently, it is being updated every time the
agreed gear changes. Due to this, if the gear got downscaled before suspend
(runtime/system), then while resuming, the PHY settings for the lower gear
will be applied first and later when scaling to max gear with REINIT, the
PHY settings for the max gear will be applied.

This adds a latency while resuming and also really not needed as the PHY
gear settings are backwards compatible i.e., we can continue using the PHY
settings for max gear with lower gear speed.

So let's update the "hs_gear" variable _only_ when the agreed gear is
greater than the current one. This guarantees that the PHY settings will be
changed only during probe time and fatal error condition.

Due to this, UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH can now be skipped
when the PM operation is in progress.

Cc: stable@vger.kernel.org
Fixes: 96a7141da332 ("scsi: ufs: core: Add support for reinitializing the UFS device")
Reported-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20230908145329.154024-1-manivannan.sadhasivam@linaro.org
Reviewed-by: Can Guo <quic_cang@quicinc.com>
Tested-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 93417518c04d15c2403b5742117c909bea8be6e9..96a5238a4b1c02cb8e4b5441d031d737f37291ef 100644 (file)
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -8722,7 +8722,8 @@ static int ufshcd_probe_hba(struct ufs_hba *hba, bool init_dev_params)
        if (ret)
                goto out;
 
-       if (hba->quirks & UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH) {
+       if (!hba->pm_op_in_progress &&
+           (hba->quirks & UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH)) {
                /* Reset the device and controller before doing reinit */
                ufshcd_device_reset(hba);
                ufshcd_hba_stop(hba);

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index dd549363fb2a8749d49a5bed26c996d0e9566cb6..4eb0581578a1b17fa867fa7344cc86eddb18ae2d 100644 (file)
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -923,8 +923,13 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
                        return ret;
                }
 
-               /* Use the agreed gear */
-               host->hs_gear = dev_req_params->gear_tx;
+               /*
+                * Update hs_gear only when the gears are scaled to a higher value. This is because,
+                * the PHY gear settings are backwards compatible and we only need to change the PHY
+                * settings while scaling to higher gears.
+                */
+               if (dev_req_params->gear_tx > host->hs_gear)
+                       host->hs_gear = dev_req_params->gear_tx;
 
                /* enable the device ref clock before changing to HS mode */
                if (!ufshcd_is_hs_mode(&hba->pwr_info) &&