lkml.org 
[lkml]   [2020]   [Mar]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH v1 1/3] scsi: ufshcd: Update the set frequency to devfreq
Date
> 
> Currently, the frequency that devfreq provides the
> driver to set always leads the clocks to be scaled up.
> Hence, round the clock-rate to the nearest frequency
> before deciding to scale.
>
> Also update the devfreq statistics of current frequency.
>
> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> ---
> drivers/scsi/ufs/ufshcd.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 2a2a63b..4607bc6 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1187,6 +1187,9 @@ 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);
> spin_lock_irqsave(hba->host->host_lock, irq_flags);
Please remind me what the spin lock is protecting here?

> if (ufshcd_eh_in_progress(hba)) {
> spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
> @@ -1201,8 +1204,13 @@ static int ufshcd_devfreq_target(struct device
> *dev,
> goto out;
> }
>
> - clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
> + /* Decide based on the rounded-off frequency and update */
> scale_up = (*freq == clki->max_freq) ? true : false;
> + if (scale_up)
> + *freq = clki->max_freq;
This was already established 2 lines above ?

> + else
> + *freq = clki->min_freq;
> + /* Update the frequency */
> if (!ufshcd_is_devfreq_scaling_required(hba, scale_up)) {
> spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
> ret = 0;
> @@ -1250,6 +1258,8 @@ 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;
>
> if (!ufshcd_is_clkscaling_supported(hba))
> return -EINVAL;
> @@ -1260,6 +1270,8 @@ 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);
> + stat->current_frequency = clki->curr_freq;
Is this a bug fix?
devfreq_simple_ondemand_func is trying to establish the busy period,
but also uses the frequency in its calculation - which I wasn't able to understand how.
Can you add a short comment why updating current_frequency is needed?


Thanks,
Avri

\
 
 \ /
  Last update: 2020-03-25 14:13    [W:0.056 / U:11.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site