[PATCH v6 1/2] scsi: ufs: Clean up ufshcd_scale_clks() and clock scaling error out path

[PATCH v6 1/2] scsi: ufs: Clean up ufshcd_scale_clks() and clock scaling error out path

[Can Guo]

From: Subhash Jadavani <subhashj@codeaurora.org>

This change introduces a func ufshcd_set_clk_freq() to explicitly
set clock frequency so that it can be used in reset_and_resotre path and
in ufshcd_scale_clks(). Meanwhile, this change cleans up the clock scaling
error out path.

Fixes: a3cd5ec55f6c ("scsi: ufs: add load based scaling of UFS gear")
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 65 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 44 insertions(+), 21 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2a2a63b..148e73a 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -855,28 +855,29 @@ static bool ufshcd_is_unipro_pa_params_tuning_req(struct ufs_hba *hba)
 		return false;
 }
 
-static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up)
+/**
+ * ufshcd_set_clk_freq - set UFS controller clock frequencies
+ * @hba: per adapter instance
+ * @scale_up: If True, set max possible frequency othewise set low frequency
+ *
+ * Returns 0 if successful
+ * Returns < 0 for any other errors
+ */
+static int ufshcd_set_clk_freq(struct ufs_hba *hba, bool scale_up)
 {
 	int ret = 0;
 	struct ufs_clk_info *clki;
 	struct list_head *head = &hba->clk_list_head;
-	ktime_t start = ktime_get();
-	bool clk_state_changed = false;
 
 	if (list_empty(head))
 		goto out;
 
-	ret = ufshcd_vops_clk_scale_notify(hba, scale_up, PRE_CHANGE);
-	if (ret)
-		return ret;
-
 	list_for_each_entry(clki, head, list) {
 		if (!IS_ERR_OR_NULL(clki->clk)) {
 			if (scale_up && clki->max_freq) {
 				if (clki->curr_freq == clki->max_freq)
 					continue;
 
-				clk_state_changed = true;
 				ret = clk_set_rate(clki->clk, clki->max_freq);
 				if (ret) {
 					dev_err(hba->dev, "%s: %s clk set rate(%dHz) failed, %d\n",
@@ -895,7 +896,6 @@ static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up)
 				if (clki->curr_freq == clki->min_freq)
 					continue;
 
-				clk_state_changed = true;
 				ret = clk_set_rate(clki->clk, clki->min_freq);
 				if (ret) {
 					dev_err(hba->dev, "%s: %s clk set rate(%dHz) failed, %d\n",
@@ -914,11 +914,37 @@ static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up)
 				clki->name, clk_get_rate(clki->clk));
 	}
 
+out:
+	return ret;
+}
+
+/**
+ * ufshcd_scale_clks - scale up or scale down UFS controller clocks
+ * @hba: per adapter instance
+ * @scale_up: True if scaling up and false if scaling down
+ *
+ * Returns 0 if successful
+ * Returns < 0 for any other errors
+ */
+static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up)
+{
+	int ret = 0;
+	ktime_t start = ktime_get();
+
+	ret = ufshcd_vops_clk_scale_notify(hba, scale_up, PRE_CHANGE);
+	if (ret)
+		goto out;
+
+	ret = ufshcd_set_clk_freq(hba, scale_up);
+	if (ret)
+		goto out;
+
 	ret = ufshcd_vops_clk_scale_notify(hba, scale_up, POST_CHANGE);
+	if (ret)
+		ufshcd_set_clk_freq(hba, !scale_up);
 
 out:
-	if (clk_state_changed)
-		trace_ufshcd_profile_clk_scaling(dev_name(hba->dev),
+	trace_ufshcd_profile_clk_scaling(dev_name(hba->dev),
 			(scale_up ? "up" : "down"),
 			ktime_to_us(ktime_sub(ktime_get(), start)), ret);
 	return ret;
@@ -1106,35 +1132,32 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
 
 	ret = ufshcd_clock_scaling_prepare(hba);
 	if (ret)
-		return ret;
+		goto out;
 
 	/* scale down the gear before scaling down clocks */
 	if (!scale_up) {
 		ret = ufshcd_scale_gear(hba, false);
 		if (ret)
-			goto out;
+			goto out_unprepare;
 	}
 
 	ret = ufshcd_scale_clks(hba, scale_up);
 	if (ret) {
 		if (!scale_up)
 			ufshcd_scale_gear(hba, true);
-		goto out;
+		goto out_unprepare;
 	}
 
 	/* scale up the gear after scaling up clocks */
 	if (scale_up) {
 		ret = ufshcd_scale_gear(hba, true);
-		if (ret) {
+		if (ret)
 			ufshcd_scale_clks(hba, false);
-			goto out;
-		}
 	}
 
-	ret = ufshcd_vops_clk_scale_notify(hba, scale_up, POST_CHANGE);
-
-out:
+out_unprepare:
 	ufshcd_clock_scaling_unprepare(hba);
+out:
 	ufshcd_release(hba);
 	return ret;
 }
@@ -6251,7 +6274,7 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 
 	/* scale up clocks to max frequency before full reinitialization */
-	ufshcd_scale_clks(hba, true);
+	ufshcd_set_clk_freq(hba, true);
 
 	err = ufshcd_hba_enable(hba);
 	if (err)
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

RE: [EXT] [PATCH v6 1/2] scsi: ufs: Clean up ufshcd_scale_clks() and clock scaling error out path

[Bean Huo (beanhuo)]

> Fixes: a3cd5ec55f6c ("scsi: ufs: add load based scaling of UFS gear")
> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
> Signed-off-by: Can Guo <cang@codeaurora.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>

Re: [PATCH v6 1/2] scsi: ufs: Clean up ufshcd_scale_clks() and clock scaling error out path

[Martin K. Petersen]

Can,

> This change introduces a func ufshcd_set_clk_freq() to explicitly set
> clock frequency so that it can be used in reset_and_resotre path and
> in ufshcd_scale_clks(). Meanwhile, this change cleans up the clock
> scaling error out path.

Applied to 5.7/scsi-queue, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v6 2/2] scsi: ufs: Do not rely on prefetched data

[Martin K. Petersen]

Can,

> We were setting bActiveICCLevel attribute for UFS device only once but
> type of this attribute has changed from persistent to volatile since
> UFS device specification v2.1. This attribute is set to the default
> value after power cycle or hardware reset event. It isn't safe to rely
> on prefetched data (only used for bActiveICCLevel attribute
> now). Hence this change removes the code related to data prefetching
> and set this parameter on every attempt to probe the UFS device.

Applied patch #2 to 5.7/scsi-queue. Awaiting Avri's feedback on patch
#1. Thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

RE: [PATCH v6 2/2] scsi: ufs: Do not rely on prefetched data

[Avri Altman]

> 
> Can,
> 
> > We were setting bActiveICCLevel attribute for UFS device only once but
> > type of this attribute has changed from persistent to volatile since
> > UFS device specification v2.1. This attribute is set to the default
> > value after power cycle or hardware reset event. It isn't safe to rely
> > on prefetched data (only used for bActiveICCLevel attribute
> > now). Hence this change removes the code related to data prefetching
> > and set this parameter on every attempt to probe the UFS device.
> 
> Applied patch #2 to 5.7/scsi-queue. Awaiting Avri's feedback on patch
> #1. Thanks!
It looks fine.
Thanks,
Avri

> 
> --
> Martin K. Petersen      Oracle Linux Engineering