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SubjectRe: [PATCH v2 2/2] scsi: ufs: Use freq table with devfreq
Hi,

On 2018년 05월 05일 07:44, Bjorn Andersson wrote:
> devfreq requires that the client operates on actual frequencies, not
> only 0 and UMAX_INT and as such UFS brok with the introduction of
> f1d981eaecf8 ("PM / devfreq: Use the available min/max frequency").
>
> This patch registers the frequencies of the first clock as opp levels
> and use these to determine if we're trying to step up or down.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>
> Chances since v1:
> - Register min_freq and max_freq as opp levels.
> - Unregister opp levels on removal, to make e.g. probe defer working
>
> drivers/scsi/ufs/ufshcd.c | 47 +++++++++++++++++++++++++++++++++------
> 1 file changed, 40 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 2253f24309ec..257614b889bd 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1168,16 +1168,13 @@ static int ufshcd_devfreq_target(struct device *dev,
> struct ufs_hba *hba = dev_get_drvdata(dev);
> ktime_t start;
> bool scale_up, sched_clk_scaling_suspend_work = false;
> + struct list_head *clk_list = &hba->clk_list_head;
> + struct ufs_clk_info *clki;
> unsigned long irq_flags;
>
> if (!ufshcd_is_clkscaling_supported(hba))
> return -EINVAL;
>
> - if ((*freq > 0) && (*freq < UINT_MAX)) {
> - dev_err(hba->dev, "%s: invalid freq = %lu\n", __func__, *freq);
> - return -EINVAL;
> - }
> -
> spin_lock_irqsave(hba->host->host_lock, irq_flags);
> if (ufshcd_eh_in_progress(hba)) {
> spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
> @@ -1187,7 +1184,13 @@ static int ufshcd_devfreq_target(struct device *dev,
> if (!hba->clk_scaling.active_reqs)
> sched_clk_scaling_suspend_work = true;
>
> - scale_up = (*freq == UINT_MAX) ? true : false;
> + if (list_empty(clk_list)) {
> + spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
> + goto out;
> + }
> +
> + clki = list_first_entry(clk_list, struct ufs_clk_info, list);
> + scale_up = (*freq == clki->max_freq) ? true : false;
> if (!ufshcd_is_devfreq_scaling_required(hba, scale_up)) {
> spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
> ret = 0;
> @@ -1257,16 +1260,29 @@ static struct devfreq_dev_profile ufs_devfreq_profile = {
>
> static int ufshcd_devfreq_init(struct ufs_hba *hba)
> {
> + struct list_head *clk_list = &hba->clk_list_head;
> + struct ufs_clk_info *clki;
> struct devfreq *devfreq;
> int ret;
>
> - devfreq = devm_devfreq_add_device(hba->dev,
> + /* Skip devfreq if we don't have any clocks in the list */
> + 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);
> +
> + devfreq = devfreq_add_device(hba->dev,
> &ufs_devfreq_profile,
> "simple_ondemand",
> NULL);
> if (IS_ERR(devfreq)) {
> 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);
> return ret;
> }
>
> @@ -1275,6 +1291,22 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
> return 0;
> }
>
> +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;
> +
> + 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);
> +}
> +
> static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
> {
> unsigned long flags;
> @@ -6966,6 +6998,7 @@ static void ufshcd_hba_exit(struct ufs_hba *hba)
> if (hba->devfreq)
> ufshcd_suspend_clkscaling(hba);
> destroy_workqueue(hba->clk_scaling.workq);
> + ufshcd_devfreq_remove(hba);
> }
> ufshcd_setup_clocks(hba, false);
> ufshcd_setup_hba_vreg(hba, false);
>

For using OPP entries for devfreq:
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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