[RFC PATCH v2 5/6] ufs: use PM OPP when scaling gears

Krzysztof Kozlowski
2022-04-11T15:45:06Z

Scaling gears requires not only scaling clocks, but also voltage levels,
e.g. via performance states.

Use the provided OPP table, to set proper OPP frequency which through
required-opps will trigger performance state change. This deprecates
the old freq-table-hz Devicetree property and old clock scaling method
in favor of PM core code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
drivers/scsi/ufs/ufshcd-pltfrm.c | 69 +++++++++++++++++++
drivers/scsi/ufs/ufshcd.c | 115 +++++++++++++++++++++++--------
drivers/scsi/ufs/ufshcd.h | 4 ++
3 files changed, 158 insertions(+), 30 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index c1d8b6f46868..edba585db0c1 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -107,6 +107,69 @@ static int ufshcd_parse_clock_info(struct ufs_hba *hba)
return ret;
}

+static int ufshcd_parse_operating_points(struct ufs_hba *hba)
+{
+ struct device *dev = hba->dev;
+ struct device_node *np = dev->of_node;
+ struct ufs_clk_info *clki;
+ const char *names[16];
+ bool clocks_done;
+ int cnt, i, ret;
+
+ if (!of_find_property(dev->of_node, "operating-points-v2", NULL))
+ return 0;
+
+ cnt = of_property_count_strings(np, "clock-names");
+ if (cnt <= 0) {
+ dev_warn(dev, "%s: Missing clock-names\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ if (cnt > ARRAY_SIZE(names)) {
+ dev_info(dev, "%s: Too many clock-names\n", __func__);
+ return -EINVAL;
+ }
+
+ /* clocks parsed by ufshcd_parse_clock_info() */
+ clocks_done = !!of_find_property(np, "freq-table-hz", NULL);
+
+ for (i = 0; i < cnt; i++) {
+ ret = of_property_read_string_index(np, "clock-names", i,
+ &names[i]);
+ if (ret)
+ return ret;
+
+ if (clocks_done)
+ continue;
+
+ clki = devm_kzalloc(dev, sizeof(*clki), GFP_KERNEL);
+ if (!clki)
+ return -ENOMEM;
+
+ clki->name = devm_kstrdup(dev, names[i], GFP_KERNEL);
+ if (!clki->name)
+ return -ENOMEM;
+
+ if (!strcmp(names[i], "ref_clk"))
+ clki->keep_link_active = true;
+
+ list_add_tail(&clki->list, &hba->clk_list_head);
+ }
+
+ ret = devm_pm_opp_set_clknames(dev, names, i);
+ if (ret)
+ return ret;
+
+ ret = devm_pm_opp_of_add_table(dev);
+ if (ret)
+ return ret;
+
+ hba->use_pm_opp = true;
+
+ return 0;
+}
+
#define MAX_PROP_SIZE 32
static int ufshcd_populate_vreg(struct device *dev, const char *name,
struct ufs_vreg **out_vreg)
@@ -360,6 +423,12 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
goto dealloc_host;
}

+ err = ufshcd_parse_operating_points(hba);
+ if (err) {
+ dev_err(dev, "%s: OPP parse failed %d\n", __func__, err);
+ goto dealloc_host;
+ }
+
ufshcd_init_lanes_per_dir(hba);

err = ufshcd_init(hba, mmio_base, irq);
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 5bfa62fa288a..aec7da18a550 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1022,6 +1022,9 @@ static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up)
int ret = 0;
ktime_t start = ktime_get();

+ if (hba->use_pm_opp)
+ return 0;
+
ret = ufshcd_vops_clk_scale_notify(hba, scale_up, PRE_CHANGE);
if (ret)
goto out;
@@ -1044,11 +1047,13 @@ static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up)
/**
* ufshcd_is_devfreq_scaling_required - check if scaling is required or not
* @hba: per adapter instance
+ * @freq: Target frequency
* @scale_up: True if scaling up and false if scaling down
*
* Returns true if scaling is required, false otherwise.
*/
static bool ufshcd_is_devfreq_scaling_required(struct ufs_hba *hba,
+ unsigned long freq,
bool scale_up)
{
struct ufs_clk_info *clki;
@@ -1057,6 +1062,9 @@ static bool ufshcd_is_devfreq_scaling_required(struct ufs_hba *hba,
if (list_empty(head))
return false;

+ if (hba->use_pm_opp)
+ return freq != hba->clk_scaling.target_freq;
+
list_for_each_entry(clki, head, list) {
if (!IS_ERR_OR_NULL(clki->clk)) {
if (scale_up && clki->max_freq) {
@@ -1155,13 +1163,15 @@ static int ufshcd_wait_for_doorbell_clr(struct ufs_hba *hba,
/**
* ufshcd_scale_gear - scale up/down UFS gear
* @hba: per adapter instance
+ * @freq: Target frequency
* @scale_up: True for scaling up gear and false for scaling down
*
* Returns 0 for success,
* Returns -EBUSY if scaling can't happen at this time
* Returns non-zero for any other errors
*/
-static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
+static int ufshcd_scale_gear(struct ufs_hba *hba, unsigned long freq,
+ bool scale_up)
{
int ret = 0;
struct ufs_pa_layer_attr new_pwr_info;
@@ -1186,6 +1196,12 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
}
}

+ if (hba->use_pm_opp && scale_up) {
+ ret = dev_pm_opp_set_rate(hba->dev, freq);
+ if (ret)
+ return ret;
+ }
+
/* check if the power mode needs to be changed or not? */
ret = ufshcd_config_pwr_mode(hba, &new_pwr_info);
if (ret)
@@ -1194,6 +1210,11 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
hba->pwr_info.gear_tx, hba->pwr_info.gear_rx,
new_pwr_info.gear_tx, new_pwr_info.gear_rx);

+ if (ret && hba->use_pm_opp && scale_up)
+ dev_pm_opp_set_rate(hba->dev, hba->devfreq->previous_freq);
+ else if (hba->use_pm_opp && !scale_up)
+ ret = dev_pm_opp_set_rate(hba->dev, freq);
+
return ret;
}

@@ -1236,13 +1257,15 @@ static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, bool writelock)
/**
* ufshcd_devfreq_scale - scale up/down UFS clocks and gear
* @hba: per adapter instance
+ * @freq: Target frequency
* @scale_up: True for scaling up and false for scalin down
*
* Returns 0 for success,
* Returns -EBUSY if scaling can't happen at this time
* Returns non-zero for any other errors
*/
-static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
+static int ufshcd_devfreq_scale(struct ufs_hba *hba, unsigned long freq,
+ bool scale_up)
{
int ret = 0;
bool is_writelock = true;
@@ -1253,7 +1276,7 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)

/* scale down the gear before scaling down clocks */
if (!scale_up) {
- ret = ufshcd_scale_gear(hba, false);
+ ret = ufshcd_scale_gear(hba, freq, false);
if (ret)
goto out_unprepare;
}
@@ -1261,13 +1284,14 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
ret = ufshcd_scale_clks(hba, scale_up);
if (ret) {
if (!scale_up)
- ufshcd_scale_gear(hba, true);
+ ufshcd_scale_gear(hba, hba->clk_scaling.target_freq,
+ true);
goto out_unprepare;
}

/* scale up the gear after scaling up clocks */
if (scale_up) {
- ret = ufshcd_scale_gear(hba, true);
+ ret = ufshcd_scale_gear(hba, freq, true);
if (ret) {
ufshcd_scale_clks(hba, false);
goto out_unprepare;
@@ -1332,9 +1356,20 @@ static int ufshcd_devfreq_target(struct device *dev,
if (!ufshcd_is_clkscaling_supported(hba))
return -EINVAL;

- clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
/* Override with the closest supported frequency */
- *freq = (unsigned long) clk_round_rate(clki->clk, *freq);
+ if (hba->use_pm_opp) {
+ struct dev_pm_opp *opp;
+
+ opp = devfreq_recommended_opp(dev, freq, flags);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+ dev_pm_opp_put(opp);
+ } else {
+ clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info,
+ list);
+ *freq = (unsigned long) clk_round_rate(clki->clk, *freq);
+ }
+
spin_lock_irqsave(hba->host->host_lock, irq_flags);
if (ufshcd_eh_in_progress(hba)) {
spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
@@ -1350,11 +1385,11 @@ static int ufshcd_devfreq_target(struct device *dev,
}

/* Decide based on the rounded-off frequency and update */
- scale_up = (*freq == clki->max_freq) ? true : false;
- if (!scale_up)
+ scale_up = (*freq > hba->clk_scaling.target_freq) ? true : false;
+ if (!hba->use_pm_opp && !scale_up)
*freq = clki->min_freq;
/* Update the frequency */
- if (!ufshcd_is_devfreq_scaling_required(hba, scale_up)) {
+ if (!ufshcd_is_devfreq_scaling_required(hba, *freq, scale_up)) {
spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
ret = 0;
goto out; /* no state change required */
@@ -1362,7 +1397,9 @@ static int ufshcd_devfreq_target(struct device *dev,
spin_unlock_irqrestore(hba->host->host_lock, irq_flags);

start = ktime_get();
- ret = ufshcd_devfreq_scale(hba, scale_up);
+ ret = ufshcd_devfreq_scale(hba, *freq, scale_up);
+ if (!ret)
+ hba->clk_scaling.target_freq = *freq;

trace_ufshcd_profile_clk_scaling(dev_name(hba->dev),
(scale_up ? "up" : "down"),
@@ -1382,8 +1419,6 @@ static int ufshcd_devfreq_get_dev_status(struct device *dev,
struct ufs_hba *hba = dev_get_drvdata(dev);
struct ufs_clk_scaling *scaling = &hba->clk_scaling;
unsigned long flags;
- struct list_head *clk_list = &hba->clk_list_head;
- struct ufs_clk_info *clki;
ktime_t curr_t;

if (!ufshcd_is_clkscaling_supported(hba))
@@ -1396,13 +1431,20 @@ static int ufshcd_devfreq_get_dev_status(struct device *dev,
if (!scaling->window_start_t)
goto start_window;

- clki = list_first_entry(clk_list, struct ufs_clk_info, list);
- /*
- * If current frequency is 0, then the ondemand governor considers
- * there's no initial frequency set. And it always requests to set
- * to max. frequency.
- */
- stat->current_frequency = clki->curr_freq;
+ if (hba->use_pm_opp) {
+ stat->current_frequency = hba->clk_scaling.target_freq;
+ } else {
+ struct list_head *clk_list = &hba->clk_list_head;
+ struct ufs_clk_info *clki;
+
+ clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+ /*
+ * If current frequency is 0, then the ondemand governor considers
+ * there's no initial frequency set. And it always requests to set
+ * to max. frequency.
+ */
+ stat->current_frequency = clki->curr_freq;
+ }
if (scaling->is_busy_started)
scaling->tot_busy_t += ktime_us_delta(curr_t,
scaling->busy_start_t);
@@ -1435,9 +1477,11 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
if (list_empty(clk_list))
return 0;

- clki = list_first_entry(clk_list, struct ufs_clk_info, list);
- dev_pm_opp_add(hba->dev, clki->min_freq, 0);
- dev_pm_opp_add(hba->dev, clki->max_freq, 0);
+ if (!hba->use_pm_opp) {
+ clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+ dev_pm_opp_add(hba->dev, clki->min_freq, 0);
+ dev_pm_opp_add(hba->dev, clki->max_freq, 0);
+ }

ufshcd_vops_config_scaling_param(hba, &hba->vps->devfreq_profile,
&hba->vps->ondemand_data);
@@ -1449,8 +1493,10 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
ret = PTR_ERR(devfreq);
dev_err(hba->dev, "Unable to register with devfreq %d\n", ret);

- dev_pm_opp_remove(hba->dev, clki->min_freq);
- dev_pm_opp_remove(hba->dev, clki->max_freq);
+ if (!hba->use_pm_opp) {
+ dev_pm_opp_remove(hba->dev, clki->min_freq);
+ dev_pm_opp_remove(hba->dev, clki->max_freq);
+ }
return ret;
}

@@ -1462,7 +1508,6 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
static void ufshcd_devfreq_remove(struct ufs_hba *hba)
{
struct list_head *clk_list = &hba->clk_list_head;
- struct ufs_clk_info *clki;

if (!hba->devfreq)
return;
@@ -1470,9 +1515,13 @@ static void ufshcd_devfreq_remove(struct ufs_hba *hba)
devfreq_remove_device(hba->devfreq);
hba->devfreq = NULL;

- clki = list_first_entry(clk_list, struct ufs_clk_info, list);
- dev_pm_opp_remove(hba->dev, clki->min_freq);
- dev_pm_opp_remove(hba->dev, clki->max_freq);
+ if (!hba->use_pm_opp) {
+ struct ufs_clk_info *clki;
+
+ clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+ dev_pm_opp_remove(hba->dev, clki->min_freq);
+ dev_pm_opp_remove(hba->dev, clki->max_freq);
+ }
}

static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
@@ -1556,8 +1605,14 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
if (value) {
ufshcd_resume_clkscaling(hba);
} else {
+ struct dev_pm_opp *opp;
+ unsigned long freq = ULONG_MAX;
+
+ opp = dev_pm_opp_find_freq_floor(dev, &freq);
+ dev_pm_opp_put(opp);
+
ufshcd_suspend_clkscaling(hba);
- err = ufshcd_devfreq_scale(hba, true);
+ err = ufshcd_devfreq_scale(hba, freq, true);
if (err)
dev_err(hba->dev, "%s: failed to scale clocks up %d\n",
__func__, err);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 1a8f7b8977e6..c224a55fd9ee 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -443,6 +443,7 @@ struct ufs_clk_scaling {
bool is_initialized;
bool is_busy_started;
bool is_suspended;
+ unsigned long target_freq;
};

#define UFS_EVENT_HIST_LENGTH 8
@@ -776,6 +777,8 @@ struct ufs_hba_monitor {
* @auto_bkops_enabled: to track whether bkops is enabled in device
* @vreg_info: UFS device voltage regulator information
* @clk_list_head: UFS host controller clocks list node head
+ * @use_pm_opp: whether OPP table is provided and scaling gears should trigger
+ * setting OPP
* @pwr_info: holds current power mode
* @max_pwr_info: keeps the device max valid pwm
* @clk_scaling_lock: used to serialize device commands and clock scaling
@@ -892,6 +895,7 @@ struct ufs_hba {
bool auto_bkops_enabled;
struct ufs_vreg_info vreg_info;
struct list_head clk_list_head;
+ bool use_pm_opp;

/* Number of requests aborts */
int req_abort_count;
--
2.32.0