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

Manivannan Sadhasivam
2022-04-19T17:04:58Z

On Mon, Apr 11, 2022 at 05:43:46PM +0200, Krzysztof Kozlowski wrote:
> 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;

Maybe freq_table?

> + 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;
> + }

How did you come up with 16 as the max clock count? Is this check necessary?

> +
> + /* clocks parsed by ufshcd_parse_clock_info() */
> + clocks_done = !!of_find_property(np, "freq-table-hz", NULL);

freq-table-hz and opp-table are mutually exclusive, isn't it?

> +
> + 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;
> +

So you don't need pre and post clock changes below?

Thanks,
Mani

> 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
>