Re: [PATCH v3 1/2] scsi: ufs: Refactor ufshcd_setup_clocks() to remove skip_ref_clk

[Can Guo <cang@xxxxxxxxxxxxxx>]

On 2020-12-01 07:01, Asutosh Das (asd) wrote:
> On 11/25/2020 6:01 PM, Can Guo wrote:
> > Remove the param skip_ref_clk from __ufshcd_setup_clocks(), but keep a 
> > flag
> > in struct ufs_clk_info to tell whether a clock can be disabled or not 
> > while
> > the link is active.
> >
> > Reviewed-by: Hongwu Su<hongwus@xxxxxxxxxxxxxx>
> > Reviewed-by: Bean Huo <beanhuo@xxxxxxxxxx>
> > Reviewed-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
> > Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> > ---
> >   drivers/scsi/ufs/ufshcd-pltfrm.c |  2 ++
> >   drivers/scsi/ufs/ufshcd.c        | 29 +++++++++--------------------
> >   drivers/scsi/ufs/ufshcd.h        |  3 +++
> >   3 files changed, 14 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c 
> > b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > index 3db0af6..873ef14 100644
> > --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > @@ -92,6 +92,8 @@ static int ufshcd_parse_clock_info(struct ufs_hba 
> > *hba)
> >   		clki->min_freq = clkfreq[i];
> >   		clki->max_freq = clkfreq[i+1];
> >   		clki->name = kstrdup(name, GFP_KERNEL);
> > +		if (!strcmp(name, "ref_clk"))
> > +			clki->keep_link_active = true;
> >   		dev_dbg(dev, "%s: min %u max %u name %s\n", "freq-table-hz",
> >   				clki->min_freq, clki->max_freq, clki->name);
> >   		list_add_tail(&clki->list, &hba->clk_list_head);
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index a7857f6..44254c9 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -221,8 +221,6 @@ static int ufshcd_eh_host_reset_handler(struct 
> > scsi_cmnd *cmd);
> >   static int ufshcd_clear_tm_cmd(struct ufs_hba *hba, int tag);
> >   static void ufshcd_hba_exit(struct ufs_hba *hba);
> >   static int ufshcd_probe_hba(struct ufs_hba *hba, bool async);
> > -static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
> > -				 bool skip_ref_clk);
> >   static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on);
> >   static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba);
> >   static inline void ufshcd_add_delay_before_dme_cmd(struct ufs_hba 
> > *hba);
> > @@ -1707,11 +1705,7 @@ static void ufshcd_gate_work(struct work_struct 
> > *work)
> >     	ufshcd_disable_irq(hba);
> >   -	if (!ufshcd_is_link_active(hba))
> > -		ufshcd_setup_clocks(hba, false);
> > -	else
> > -		/* If link is active, device ref_clk can't be switched off */
> > -		__ufshcd_setup_clocks(hba, false, true);
> > +	ufshcd_setup_clocks(hba, false);
> >     	/*
> >   	 * In case you are here to cancel this work the gating state
> > @@ -7990,8 +7984,7 @@ static int ufshcd_init_hba_vreg(struct ufs_hba 
> > *hba)
> >   	return 0;
> >   }
> >   -static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
> > -					bool skip_ref_clk)
> > +static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on)
> >   {
> >   	int ret = 0;
> >   	struct ufs_clk_info *clki;
> > @@ -8009,7 +8002,12 @@ static int __ufshcd_setup_clocks(struct ufs_hba 
> > *hba, bool on,
> >     	list_for_each_entry(clki, head, list) {
> >   		if (!IS_ERR_OR_NULL(clki->clk)) {
> > -			if (skip_ref_clk && !strcmp(clki->name, "ref_clk"))
> > +			/*
> > +			 * Don't disable clocks which are needed
> > +			 * to keep the link active.
> > +			 */
> > +			if (ufshcd_is_link_active(hba) &&
> > +			    clki->keep_link_active)
> >   				continue;
> >     			clk_state_changed = on ^ clki->enabled;
> > @@ -8054,11 +8052,6 @@ static int __ufshcd_setup_clocks(struct ufs_hba 
> > *hba, bool on,
> >   	return ret;
> >   }
> >   -static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on)
> > -{
> > -	return  __ufshcd_setup_clocks(hba, on, false);
> > -}
> > -
> >   static int ufshcd_init_clocks(struct ufs_hba *hba)
> >   {
> >   	int ret = 0;
> > @@ -8577,11 +8570,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, 
> > enum ufs_pm_op pm_op)
> >   	 */
> >   	ufshcd_disable_irq(hba);
> >   -	if (!ufshcd_is_link_active(hba))
> > -		ufshcd_setup_clocks(hba, false);
> > -	else
> > -		/* If link is active, device ref_clk can't be switched off */
> > -		__ufshcd_setup_clocks(hba, false, true);
> > +	ufshcd_setup_clocks(hba, false);
> >     	if (ufshcd_is_clkgating_allowed(hba)) {
> >   		hba->clk_gating.state = CLKS_OFF;
> > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> > index 66e5338..6f0f2d4 100644
> > --- a/drivers/scsi/ufs/ufshcd.h
> > +++ b/drivers/scsi/ufs/ufshcd.h
> > @@ -229,6 +229,8 @@ struct ufs_dev_cmd {
> >    * @max_freq: maximum frequency supported by the clock
> >    * @min_freq: min frequency that can be used for clock scaling
> >    * @curr_freq: indicates the current frequency that it is set to
> > + * @keep_link_active: indicates that the clk should not be disabled 
> > if
> > +		      link is active
> >    * @enabled: variable to check against multiple enable/disable
> >    */
> >   struct ufs_clk_info {
> > @@ -238,6 +240,7 @@ struct ufs_clk_info {
> >   	u32 max_freq;
> >   	u32 min_freq;
> >   	u32 curr_freq;
> > +	bool keep_link_active;
>
> Nitpick - How about 'always-on' instead of 'keep_link_active'?

Hi Asutosh,

But it is not always-on, during suspend, it is on when rpm/spm-lvl is 1
and 2, off when rpm/spm-lvl is 3, 4 and 5, depending on the link state.

Thanks,

Can Guo.

> >   	bool enabled;
> >   };