[PATCH V1 1/2] scsi: ufs: ufs-qcom: Add specified gear support for multi gear scaling

[Nitin Rawat <nitin.rawat@oss.qualcomm.com>]

From: Ziqi Chen <ziqi.chen@oss.qualcomm.com>

The UFS clock frequency and gear speed do not necessarily have a strict
one-to-one correspondence on all platforms. Introduce a device tree
based configuration interface that allows specifying the HS gear
speed for each supported operating frequency via the "opp-level"
property in the OPP table. When this property is not configured, the
driver falls back to the default frequency-to-gear mapping table.

Signed-off-by: Ziqi Chen <ziqi.chen@oss.qualcomm.com>
Signed-off-by: Nitin Rawat <nitin.rawat@oss.qualcomm.com>
---
 drivers/ufs/host/ufs-qcom.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 0f2e083b04fd..aa2ac2cd2b69 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -2460,8 +2460,9 @@ static unsigned long ufs_qcom_opp_freq_to_clk_freq(struct ufs_hba *hba,
 	bool found = false;

 	opp = dev_pm_opp_find_freq_exact_indexed(hba->dev, freq, 0, true);
-	if (IS_ERR(opp)) {
-		dev_err(hba->dev, "Failed to find OPP for exact frequency %lu\n", freq);
+	if (IS_ERR_OR_NULL(opp)) {
+		dev_err(hba->dev, "%s: Failed to find OPP for exact frequency %lu\n",
+			__func__, freq);
 		return 0;
 	}

@@ -2489,12 +2490,32 @@ static unsigned long ufs_qcom_opp_freq_to_clk_freq(struct ufs_hba *hba,

 static u32 ufs_qcom_freq_to_gear_speed(struct ufs_hba *hba, unsigned long freq)
 {
-	u32 gear = UFS_HS_DONT_CHANGE;
+	struct dev_pm_opp *opp;
 	unsigned long unipro_freq;
+	u32 gear = UFS_HS_DONT_CHANGE;

 	if (!hba->use_pm_opp)
 		return gear;

+	opp = dev_pm_opp_find_freq_exact_indexed(hba->dev, freq, 0, true);
+	if (IS_ERR_OR_NULL(opp)) {
+		dev_err(hba->dev, "%s: Failed to find OPP for exact frequency %lu\n",
+			__func__, freq);
+		return gear;
+	}
+
+	/* Get HS gear speed from 'opp-level' */
+	gear = dev_pm_opp_get_level(opp);
+	dev_pm_opp_put(opp);
+
+	/*
+	 * Greater than max gear means that there is no specified gear configured in DT
+	 * or the specified gear is invalid.
+	 */
+	if (gear <= hba->max_pwr_info.info.gear_rx)
+		return gear;
+
+	gear = UFS_HS_DONT_CHANGE;
 	unipro_freq = ufs_qcom_opp_freq_to_clk_freq(hba, freq, "core_clk_unipro");
 	switch (unipro_freq) {
 	case 403000000:
@@ -2515,7 +2536,8 @@ static u32 ufs_qcom_freq_to_gear_speed(struct ufs_hba *hba, unsigned long freq)
 		gear = UFS_HS_G1;
 		break;
 	default:
-		dev_err(hba->dev, "%s: Unsupported clock freq : %lu\n", __func__, freq);
+		dev_err(hba->dev, "%s: Unsupported clock freq [sys_clk: %lu, unipro_clk: %lu]\n",
+			__func__, freq, unipro_freq);
 		return UFS_HS_DONT_CHANGE;
 	}

--
2.34.1