scsi: ufs: qcom: Power down the controller/device during system suspend for SM8550/SM8650 SoCs

SM8550 and SM8650 SoCs doesn't support UFS PHY retention. So once these SoCs
reaches the low power state (CX power collapse) during system suspend, all
the PHY hardware state gets lost. This leads to the UFS resume failure:

ufshcd-qcom 1d84000.ufs: ufshcd_uic_hibern8_exit: hibern8 exit failed. ret = 5
ufshcd-qcom 1d84000.ufs: __ufshcd_wl_resume: hibern8 exit failed 5
ufs_device_wlun 0:0:0:49488: ufshcd_wl_resume failed: 5
ufs_device_wlun 0:0:0:49488: PM: dpm_run_callback(): scsi_bus_resume+0x0/0x84 returns 5
ufs_device_wlun 0:0:0:49488: PM: failed to resume async: error 5

With the default system suspend level of UFS_PM_LVL_3, the power domain for
UFS PHY needs to be kept always ON to retain the state. But this would
prevent these SoCs from reaching the CX power collapse state, leading to
poor power saving during system suspend.

So to fix this issue without affecting the power saving, set
'ufs_qcom_drvdata::no_phy_retention' to true which sets 'hba->spm_lvl' to
UFS_PM_LVL_5 to allow both the controller and device (in turn the PHY) to be
powered down during system suspend for these SoCs by default.

Cc: [e-mail] # 6.3
Fixes: 35cf1aaab169 ("arm64: dts: qcom: sm8550: Add UFS host controller and phy nodes")
Fixes: 10e024671295 ("arm64: dts: qcom: sm8650: add interconnect dependent device nodes")
Reported-by: Neil Armstrong <[e-mail]>
Tested-by: Amit Pundir <[e-mail]> # on SM8550-HDK
Reviewed-by: Bart Van Assche <[e-mail]>
Tested-by: Neil Armstrong <[e-mail]> # on SM8550-QRD
Signed-off-by: Manivannan Sadhasivam <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/ufs/host/ufs-qcom.c

···
 	struct device *dev = hba->dev;
 	struct ufs_qcom_host *host;
 	struct ufs_clk_info *clki;
+	const struct ufs_qcom_drvdata *drvdata = of_device_get_match_data(hba->dev);
 
 	host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
 	if (!host)
···
 		/* Failure is non-fatal */
 		dev_warn(dev, "%s: failed to configure the testbus %d\n",
 				__func__, err);
+
+	if (drvdata && drvdata->no_phy_retention)
+		hba->spm_lvl = UFS_PM_LVL_5;
 
 	return 0;
 
···
 
 static const struct ufs_qcom_drvdata ufs_qcom_sm8550_drvdata = {
 	.quirks = UFSHCD_QUIRK_BROKEN_LSDBS_CAP,
+	.no_phy_retention = true,
 };
 
 static const struct of_device_id ufs_qcom_of_match[] __maybe_unused = {

drivers/ufs/host/ufs-qcom.h

···
 
 struct ufs_qcom_drvdata {
 	enum ufshcd_quirks quirks;
+	bool no_phy_retention;
 };
 
 static inline u32