diff mbox series

[v2,2/3] clk: ti: check clock type before doing autoidle ops

Message ID 20181110203115.13335-3-andreas@kemnade.info (mailing list archive)
State Changes Requested, archived
Headers show
Series mach-omap2: handle autoidle denial | expand

Commit Message

Andreas Kemnade Nov. 10, 2018, 8:31 p.m. UTC
Code might use autoidle api with clocks not being omap2 clocks,
so check if clock type is not basic

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
New in v2
---
 drivers/clk/ti/autoidle.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Comments

Stephen Boyd Nov. 30, 2018, 12:25 a.m. UTC | #1
Quoting Andreas Kemnade (2018-11-10 12:31:14)
> Code might use autoidle api with clocks not being omap2 clocks,
> so check if clock type is not basic
> 
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> ---
> New in v2
> ---
>  drivers/clk/ti/autoidle.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
> index 161f67850393..5bdae5552d38 100644
> --- a/drivers/clk/ti/autoidle.c
> +++ b/drivers/clk/ti/autoidle.c
> @@ -54,8 +54,12 @@ static DEFINE_SPINLOCK(autoidle_spinlock);
>  int omap2_clk_deny_idle(struct clk *clk)
>  {
>         struct clk_hw_omap *c;
> +       struct clk_hw *hw = __clk_get_hw(clk);
>  
> -       c = to_clk_hw_omap(__clk_get_hw(clk));
> +       if (clk_hw_get_flags(hw) & CLK_IS_BASIC)

Please try to avoid using CLK_IS_BASIC if at all possible. Can you?
Maybe add some flag in clk_hw_omap() instead?
Andreas Kemnade Nov. 30, 2018, 6:15 a.m. UTC | #2
Hi Stephen,

On Thu, 29 Nov 2018 16:25:05 -0800
Stephen Boyd <sboyd@kernel.org> wrote:

> Quoting Andreas Kemnade (2018-11-10 12:31:14)
> > Code might use autoidle api with clocks not being omap2 clocks,
> > so check if clock type is not basic
> > 
> > Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> > ---
> > New in v2
> > ---
> >  drivers/clk/ti/autoidle.c | 12 ++++++++++--
> >  1 file changed, 10 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
> > index 161f67850393..5bdae5552d38 100644
> > --- a/drivers/clk/ti/autoidle.c
> > +++ b/drivers/clk/ti/autoidle.c
> > @@ -54,8 +54,12 @@ static DEFINE_SPINLOCK(autoidle_spinlock);
> >  int omap2_clk_deny_idle(struct clk *clk)
> >  {
> >         struct clk_hw_omap *c;
> > +       struct clk_hw *hw = __clk_get_hw(clk);
> >  
> > -       c = to_clk_hw_omap(__clk_get_hw(clk));
> > +       if (clk_hw_get_flags(hw) & CLK_IS_BASIC)  
> 
> Please try to avoid using CLK_IS_BASIC if at all possible. Can you?
> Maybe add some flag in clk_hw_omap() instead?
> 
hmm, Tero suggested that.
But to check flags in clk_hw_omap I first need to know that there is a
clk_hw_omap behind clk_hw. And for that I either need to check flags in
clk_hw or do more changes in the omap_hwmod code.

Regards,
Andreas
Stephen Boyd Nov. 30, 2018, 7:20 a.m. UTC | #3
Quoting Andreas Kemnade (2018-11-29 22:15:34)
> Hi Stephen,
> 
> On Thu, 29 Nov 2018 16:25:05 -0800
> Stephen Boyd <sboyd@kernel.org> wrote:
> 
> > Quoting Andreas Kemnade (2018-11-10 12:31:14)
> > > Code might use autoidle api with clocks not being omap2 clocks,
> > > so check if clock type is not basic
> > > 
> > > Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> > > ---
> > > New in v2
> > > ---
> > >  drivers/clk/ti/autoidle.c | 12 ++++++++++--
> > >  1 file changed, 10 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
> > > index 161f67850393..5bdae5552d38 100644
> > > --- a/drivers/clk/ti/autoidle.c
> > > +++ b/drivers/clk/ti/autoidle.c
> > > @@ -54,8 +54,12 @@ static DEFINE_SPINLOCK(autoidle_spinlock);
> > >  int omap2_clk_deny_idle(struct clk *clk)
> > >  {
> > >         struct clk_hw_omap *c;
> > > +       struct clk_hw *hw = __clk_get_hw(clk);
> > >  
> > > -       c = to_clk_hw_omap(__clk_get_hw(clk));
> > > +       if (clk_hw_get_flags(hw) & CLK_IS_BASIC)  
> > 
> > Please try to avoid using CLK_IS_BASIC if at all possible. Can you?
> > Maybe add some flag in clk_hw_omap() instead?
> > 
> hmm, Tero suggested that.
> But to check flags in clk_hw_omap I first need to know that there is a
> clk_hw_omap behind clk_hw. And for that I either need to check flags in
> clk_hw or do more changes in the omap_hwmod code.

Can you do it? The omap code is the only user of CLK_IS_BASIC. All the
other users are marking clks with this but there is no reason to do so.
I'll go make another pass over the tree and nuke those ones from orbit.
Tero Kristo Nov. 30, 2018, 7:35 a.m. UTC | #4
On 30/11/2018 09:20, Stephen Boyd wrote:
> Quoting Andreas Kemnade (2018-11-29 22:15:34)
>> Hi Stephen,
>>
>> On Thu, 29 Nov 2018 16:25:05 -0800
>> Stephen Boyd <sboyd@kernel.org> wrote:
>>
>>> Quoting Andreas Kemnade (2018-11-10 12:31:14)
>>>> Code might use autoidle api with clocks not being omap2 clocks,
>>>> so check if clock type is not basic
>>>>
>>>> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
>>>> ---
>>>> New in v2
>>>> ---
>>>>   drivers/clk/ti/autoidle.c | 12 ++++++++++--
>>>>   1 file changed, 10 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
>>>> index 161f67850393..5bdae5552d38 100644
>>>> --- a/drivers/clk/ti/autoidle.c
>>>> +++ b/drivers/clk/ti/autoidle.c
>>>> @@ -54,8 +54,12 @@ static DEFINE_SPINLOCK(autoidle_spinlock);
>>>>   int omap2_clk_deny_idle(struct clk *clk)
>>>>   {
>>>>          struct clk_hw_omap *c;
>>>> +       struct clk_hw *hw = __clk_get_hw(clk);
>>>>   
>>>> -       c = to_clk_hw_omap(__clk_get_hw(clk));
>>>> +       if (clk_hw_get_flags(hw) & CLK_IS_BASIC)
>>>
>>> Please try to avoid using CLK_IS_BASIC if at all possible. Can you?
>>> Maybe add some flag in clk_hw_omap() instead?
>>>
>> hmm, Tero suggested that.
>> But to check flags in clk_hw_omap I first need to know that there is a
>> clk_hw_omap behind clk_hw. And for that I either need to check flags in
>> clk_hw or do more changes in the omap_hwmod code.
> 
> Can you do it? The omap code is the only user of CLK_IS_BASIC. All the
> other users are marking clks with this but there is no reason to do so.
> I'll go make another pass over the tree and nuke those ones from orbit.

The reason for using this flag is because OMAP uses two clock types 
around, the basic clocks like fixed-factor-clock/fixed-clock, and then 
all the omap derivatives, which can be cast to clk_hw_omap. If we want 
to avoid usage of CLK_IS_BASIC, we need to copy paste the remaining 
basic code under drivers/clk/ti/ and convert them to use clk_hw_omap as 
internal datatype. Is this preferred?

-Tero
--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Stephen Boyd Nov. 30, 2018, 7:57 a.m. UTC | #5
Quoting Tero Kristo (2018-11-29 23:35:35)
> On 30/11/2018 09:20, Stephen Boyd wrote:
> > Quoting Andreas Kemnade (2018-11-29 22:15:34)
> >> Hi Stephen,
> >>
> >> On Thu, 29 Nov 2018 16:25:05 -0800
> >> Stephen Boyd <sboyd@kernel.org> wrote:
> >>
> >>> Quoting Andreas Kemnade (2018-11-10 12:31:14)
> >>>> Code might use autoidle api with clocks not being omap2 clocks,
> >>>> so check if clock type is not basic
> >>>>
> >>>> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> >>>> ---
> >>>> New in v2
> >>>> ---
> >>>>   drivers/clk/ti/autoidle.c | 12 ++++++++++--
> >>>>   1 file changed, 10 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
> >>>> index 161f67850393..5bdae5552d38 100644
> >>>> --- a/drivers/clk/ti/autoidle.c
> >>>> +++ b/drivers/clk/ti/autoidle.c
> >>>> @@ -54,8 +54,12 @@ static DEFINE_SPINLOCK(autoidle_spinlock);
> >>>>   int omap2_clk_deny_idle(struct clk *clk)
> >>>>   {
> >>>>          struct clk_hw_omap *c;
> >>>> +       struct clk_hw *hw = __clk_get_hw(clk);
> >>>>   
> >>>> -       c = to_clk_hw_omap(__clk_get_hw(clk));
> >>>> +       if (clk_hw_get_flags(hw) & CLK_IS_BASIC)
> >>>
> >>> Please try to avoid using CLK_IS_BASIC if at all possible. Can you?
> >>> Maybe add some flag in clk_hw_omap() instead?
> >>>
> >> hmm, Tero suggested that.
> >> But to check flags in clk_hw_omap I first need to know that there is a
> >> clk_hw_omap behind clk_hw. And for that I either need to check flags in
> >> clk_hw or do more changes in the omap_hwmod code.
> > 
> > Can you do it? The omap code is the only user of CLK_IS_BASIC. All the
> > other users are marking clks with this but there is no reason to do so.
> > I'll go make another pass over the tree and nuke those ones from orbit.
> 
> The reason for using this flag is because OMAP uses two clock types 
> around, the basic clocks like fixed-factor-clock/fixed-clock, and then 
> all the omap derivatives, which can be cast to clk_hw_omap. If we want 
> to avoid usage of CLK_IS_BASIC, we need to copy paste the remaining 
> basic code under drivers/clk/ti/ and convert them to use clk_hw_omap as 
> internal datatype. Is this preferred?
> 

No that is not preferred. Can the omap2_clk_deny_idle() function be
integrated closer into the clk framework in some way that allows it to
be part of the clk_ops structure? And then have that take a clk_hw
structure instead of a struct clk? I haven't looked at this in any
detail whatsoever so I may be way off right now.
Tero Kristo Nov. 30, 2018, 9:20 a.m. UTC | #6
On 30/11/2018 09:57, Stephen Boyd wrote:
> Quoting Tero Kristo (2018-11-29 23:35:35)
>> On 30/11/2018 09:20, Stephen Boyd wrote:
>>> Quoting Andreas Kemnade (2018-11-29 22:15:34)
>>>> Hi Stephen,
>>>>
>>>> On Thu, 29 Nov 2018 16:25:05 -0800
>>>> Stephen Boyd <sboyd@kernel.org> wrote:
>>>>
>>>>> Quoting Andreas Kemnade (2018-11-10 12:31:14)
>>>>>> Code might use autoidle api with clocks not being omap2 clocks,
>>>>>> so check if clock type is not basic
>>>>>>
>>>>>> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
>>>>>> ---
>>>>>> New in v2
>>>>>> ---
>>>>>>    drivers/clk/ti/autoidle.c | 12 ++++++++++--
>>>>>>    1 file changed, 10 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
>>>>>> index 161f67850393..5bdae5552d38 100644
>>>>>> --- a/drivers/clk/ti/autoidle.c
>>>>>> +++ b/drivers/clk/ti/autoidle.c
>>>>>> @@ -54,8 +54,12 @@ static DEFINE_SPINLOCK(autoidle_spinlock);
>>>>>>    int omap2_clk_deny_idle(struct clk *clk)
>>>>>>    {
>>>>>>           struct clk_hw_omap *c;
>>>>>> +       struct clk_hw *hw = __clk_get_hw(clk);
>>>>>>    
>>>>>> -       c = to_clk_hw_omap(__clk_get_hw(clk));
>>>>>> +       if (clk_hw_get_flags(hw) & CLK_IS_BASIC)
>>>>>
>>>>> Please try to avoid using CLK_IS_BASIC if at all possible. Can you?
>>>>> Maybe add some flag in clk_hw_omap() instead?
>>>>>
>>>> hmm, Tero suggested that.
>>>> But to check flags in clk_hw_omap I first need to know that there is a
>>>> clk_hw_omap behind clk_hw. And for that I either need to check flags in
>>>> clk_hw or do more changes in the omap_hwmod code.
>>>
>>> Can you do it? The omap code is the only user of CLK_IS_BASIC. All the
>>> other users are marking clks with this but there is no reason to do so.
>>> I'll go make another pass over the tree and nuke those ones from orbit.
>>
>> The reason for using this flag is because OMAP uses two clock types
>> around, the basic clocks like fixed-factor-clock/fixed-clock, and then
>> all the omap derivatives, which can be cast to clk_hw_omap. If we want
>> to avoid usage of CLK_IS_BASIC, we need to copy paste the remaining
>> basic code under drivers/clk/ti/ and convert them to use clk_hw_omap as
>> internal datatype. Is this preferred?
>>
> 
> No that is not preferred. Can the omap2_clk_deny_idle() function be
> integrated closer into the clk framework in some way that allows it to
> be part of the clk_ops structure? And then have that take a clk_hw
> structure instead of a struct clk? I haven't looked at this in any
> detail whatsoever so I may be way off right now.

It could be added under the main clk_ops struct, however this would 
introduce two new func pointers to it which are not used by anything 
else but OMAP. Are you aware of any other platforms requiring similar 
feature?

-Tero

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Andreas Kemnade Nov. 30, 2018, 12:17 p.m. UTC | #7
Hi Tero,

On Fri, 30 Nov 2018 11:20:49 +0200
Tero Kristo <t-kristo@ti.com> wrote:

> On 30/11/2018 09:57, Stephen Boyd wrote:
> > Quoting Tero Kristo (2018-11-29 23:35:35)  
> >> On 30/11/2018 09:20, Stephen Boyd wrote:  
> >>> Quoting Andreas Kemnade (2018-11-29 22:15:34)  
> >>>> Hi Stephen,
> >>>>
> >>>> On Thu, 29 Nov 2018 16:25:05 -0800
> >>>> Stephen Boyd <sboyd@kernel.org> wrote:
> >>>>  
> >>>>> Quoting Andreas Kemnade (2018-11-10 12:31:14)  
> >>>>>> Code might use autoidle api with clocks not being omap2 clocks,
> >>>>>> so check if clock type is not basic
> >>>>>>
> >>>>>> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> >>>>>> ---
> >>>>>> New in v2
> >>>>>> ---
> >>>>>>    drivers/clk/ti/autoidle.c | 12 ++++++++++--
> >>>>>>    1 file changed, 10 insertions(+), 2 deletions(-)
> >>>>>>
> >>>>>> diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
> >>>>>> index 161f67850393..5bdae5552d38 100644
> >>>>>> --- a/drivers/clk/ti/autoidle.c
> >>>>>> +++ b/drivers/clk/ti/autoidle.c
> >>>>>> @@ -54,8 +54,12 @@ static DEFINE_SPINLOCK(autoidle_spinlock);
> >>>>>>    int omap2_clk_deny_idle(struct clk *clk)
> >>>>>>    {
> >>>>>>           struct clk_hw_omap *c;
> >>>>>> +       struct clk_hw *hw = __clk_get_hw(clk);
> >>>>>>    
> >>>>>> -       c = to_clk_hw_omap(__clk_get_hw(clk));
> >>>>>> +       if (clk_hw_get_flags(hw) & CLK_IS_BASIC)  
> >>>>>
> >>>>> Please try to avoid using CLK_IS_BASIC if at all possible. Can you?
> >>>>> Maybe add some flag in clk_hw_omap() instead?
> >>>>>  
> >>>> hmm, Tero suggested that.
> >>>> But to check flags in clk_hw_omap I first need to know that there is a
> >>>> clk_hw_omap behind clk_hw. And for that I either need to check flags in
> >>>> clk_hw or do more changes in the omap_hwmod code.  
> >>>
> >>> Can you do it? The omap code is the only user of CLK_IS_BASIC. All the
> >>> other users are marking clks with this but there is no reason to do so.
> >>> I'll go make another pass over the tree and nuke those ones from orbit.  
> >>
> >> The reason for using this flag is because OMAP uses two clock types
> >> around, the basic clocks like fixed-factor-clock/fixed-clock, and then
> >> all the omap derivatives, which can be cast to clk_hw_omap. If we want
> >> to avoid usage of CLK_IS_BASIC, we need to copy paste the remaining
> >> basic code under drivers/clk/ti/ and convert them to use clk_hw_omap as
> >> internal datatype. Is this preferred?
> >>  
> > 
> > No that is not preferred. Can the omap2_clk_deny_idle() function be
> > integrated closer into the clk framework in some way that allows it to
> > be part of the clk_ops structure? And then have that take a clk_hw
> > structure instead of a struct clk? I haven't looked at this in any
> > detail whatsoever so I may be way off right now.  
> 
> It could be added under the main clk_ops struct, however this would 
> introduce two new func pointers to it which are not used by anything 
> else but OMAP. Are you aware of any other platforms requiring similar 
> feature?

The question here is also how we organize the procedure here. One patchset
fixing nasty problems and another mainly reorganize things? Where do we draw
the line between these two? If we have the autoidle code in main clk_ops,
we could also think whether other autoidle code should go into main code.

Regards,
Andreas
Tony Lindgren Nov. 30, 2018, 3:37 p.m. UTC | #8
Hi,

* Tero Kristo <t-kristo@ti.com> [181130 09:21]:
> On 30/11/2018 09:57, Stephen Boyd wrote:
> > No that is not preferred. Can the omap2_clk_deny_idle() function be
> > integrated closer into the clk framework in some way that allows it to
> > be part of the clk_ops structure? And then have that take a clk_hw
> > structure instead of a struct clk? I haven't looked at this in any
> > detail whatsoever so I may be way off right now.
> 
> It could be added under the main clk_ops struct, however this would
> introduce two new func pointers to it which are not used by anything else
> but OMAP. Are you aware of any other platforms requiring similar feature?

From consumer usage point of view, I'm still wondering about
the relationship of clk_deny_idle() and clkdm_deny_idle().

It seems that we need to allow reset control drivers call
clk_deny_idle() for the duration of reset. And it seems the
clk_deny_idle() should propagate to also up to the related
clock domain driver to do clkdm_deny_idle().

So maybe clk_deny_idle() is could just be something like:

dev = clk_get_device(clk);
...
error = pm_runtime_get(dev);
...
pm_runtime_put(dev);
...

And that way it would just propagate to the parent clock
domain driver and the clock framework does not need to know
about clockdomains. A clockdomain could be just a genpd
domain.

Or do you guys have better ideas?

Regards,

Tony
Stephen Boyd Nov. 30, 2018, 11:51 p.m. UTC | #9
Quoting Tony Lindgren (2018-11-30 07:37:29)
> Hi,
> 
> * Tero Kristo <t-kristo@ti.com> [181130 09:21]:
> > On 30/11/2018 09:57, Stephen Boyd wrote:
> > > No that is not preferred. Can the omap2_clk_deny_idle() function be
> > > integrated closer into the clk framework in some way that allows it to
> > > be part of the clk_ops structure? And then have that take a clk_hw
> > > structure instead of a struct clk? I haven't looked at this in any
> > > detail whatsoever so I may be way off right now.
> > 
> > It could be added under the main clk_ops struct, however this would
> > introduce two new func pointers to it which are not used by anything else
> > but OMAP. Are you aware of any other platforms requiring similar feature?
> 
> From consumer usage point of view, I'm still wondering about
> the relationship of clk_deny_idle() and clkdm_deny_idle().
> 
> It seems that we need to allow reset control drivers call
> clk_deny_idle() for the duration of reset. And it seems the
> clk_deny_idle() should propagate to also up to the related
> clock domain driver to do clkdm_deny_idle().
> 
> So maybe clk_deny_idle() is could just be something like:
> 
> dev = clk_get_device(clk);
> ...
> error = pm_runtime_get(dev);
> ...
> pm_runtime_put(dev);
> ...
> 
> And that way it would just propagate to the parent clock
> domain driver and the clock framework does not need to know
> about clockdomains. A clockdomain could be just a genpd
> domain.
> 
> Or do you guys have better ideas?
> 

Wouldn't the device link in clk framework patches do this for you if we
had the RUNTIME_PM flag passed in. If this is about keeping the clock
controller active when a consumer device is using it then I think it may
work.
Tony Lindgren Dec. 3, 2018, 3:39 p.m. UTC | #10
* Stephen Boyd <sboyd@kernel.org> [181130 23:52]:
> Quoting Tony Lindgren (2018-11-30 07:37:29)
> > Hi,
> > 
> > * Tero Kristo <t-kristo@ti.com> [181130 09:21]:
> > > On 30/11/2018 09:57, Stephen Boyd wrote:
> > > > No that is not preferred. Can the omap2_clk_deny_idle() function be
> > > > integrated closer into the clk framework in some way that allows it to
> > > > be part of the clk_ops structure? And then have that take a clk_hw
> > > > structure instead of a struct clk? I haven't looked at this in any
> > > > detail whatsoever so I may be way off right now.
> > > 
> > > It could be added under the main clk_ops struct, however this would
> > > introduce two new func pointers to it which are not used by anything else
> > > but OMAP. Are you aware of any other platforms requiring similar feature?
> > 
> > From consumer usage point of view, I'm still wondering about
> > the relationship of clk_deny_idle() and clkdm_deny_idle().
> > 
> > It seems that we need to allow reset control drivers call
> > clk_deny_idle() for the duration of reset. And it seems the
> > clk_deny_idle() should propagate to also up to the related
> > clock domain driver to do clkdm_deny_idle().
> > 
> > So maybe clk_deny_idle() is could just be something like:
> > 
> > dev = clk_get_device(clk);
> > ...
> > error = pm_runtime_get(dev);
> > ...
> > pm_runtime_put(dev);
> > ...
> > 
> > And that way it would just propagate to the parent clock
> > domain driver and the clock framework does not need to know
> > about clockdomains. A clockdomain could be just a genpd
> > domain.
> > 
> > Or do you guys have better ideas?
> > 
> 
> Wouldn't the device link in clk framework patches do this for you if we
> had the RUNTIME_PM flag passed in. If this is about keeping the clock
> controller active when a consumer device is using it then I think it may
> work.

The consumer device stays active just fine with PM runtime
calls. So yes, the problem is keeping a clock controller forced
active for the period of consumer device reset. Other than
that typically autoidle can be just kept enabled.

Below is a clarified suggested example usage if we wanted to
use PM runtime on a clock controller device from a consumer
device reset driver:

error = pm_runtime_get_dev()
...
cdev = clk_get_device(clk);
...
error = pm_runtime_get(cdev);
...
/* Do the consumer device reset here */
...
pm_runtime_put(cdev);
pm_runtime_put(dev);

Regards,

Tony
Andreas Kemnade Dec. 3, 2018, 4:22 p.m. UTC | #11
On Mon, 3 Dec 2018 07:39:10 -0800
Tony Lindgren <tony@atomide.com> wrote:

> * Stephen Boyd <sboyd@kernel.org> [181130 23:52]:
> > Quoting Tony Lindgren (2018-11-30 07:37:29)  
> > > Hi,
> > > 
> > > * Tero Kristo <t-kristo@ti.com> [181130 09:21]:  
> > > > On 30/11/2018 09:57, Stephen Boyd wrote:  
> > > > > No that is not preferred. Can the omap2_clk_deny_idle() function be
> > > > > integrated closer into the clk framework in some way that allows it to
> > > > > be part of the clk_ops structure? And then have that take a clk_hw
> > > > > structure instead of a struct clk? I haven't looked at this in any
> > > > > detail whatsoever so I may be way off right now.  
> > > > 
> > > > It could be added under the main clk_ops struct, however this would
> > > > introduce two new func pointers to it which are not used by anything else
> > > > but OMAP. Are you aware of any other platforms requiring similar feature?  
> > > 
> > > From consumer usage point of view, I'm still wondering about
> > > the relationship of clk_deny_idle() and clkdm_deny_idle().
> > > 
> > > It seems that we need to allow reset control drivers call
> > > clk_deny_idle() for the duration of reset. And it seems the
> > > clk_deny_idle() should propagate to also up to the related
> > > clock domain driver to do clkdm_deny_idle().
> > > 
> > > So maybe clk_deny_idle() is could just be something like:
> > > 
> > > dev = clk_get_device(clk);
> > > ...
> > > error = pm_runtime_get(dev);
> > > ...
> > > pm_runtime_put(dev);
> > > ...
> > > 
> > > And that way it would just propagate to the parent clock
> > > domain driver and the clock framework does not need to know
> > > about clockdomains. A clockdomain could be just a genpd
> > > domain.
> > > 
> > > Or do you guys have better ideas?
> > >   
> > 
> > Wouldn't the device link in clk framework patches do this for you if we
> > had the RUNTIME_PM flag passed in. If this is about keeping the clock
> > controller active when a consumer device is using it then I think it may
> > work.  
> 
> The consumer device stays active just fine with PM runtime
> calls. So yes, the problem is keeping a clock controller forced
> active for the period of consumer device reset. Other than
> that typically autoidle can be just kept enabled.
> 
Are we still talking about the same problem? Maybe I am losing track
here. Just to make sure. 
The patch series was about disabling autoidle for devices which cannot
work with it during normal operation. Not during reset or something
like that. 
Or is the keep-clock-active-during-reset just a requirement for bigger
restructuring ideas?

Regards,
Andreas
Stephen Boyd Dec. 3, 2018, 5:06 p.m. UTC | #12
Quoting Tony Lindgren (2018-12-03 07:39:10)
> * Stephen Boyd <sboyd@kernel.org> [181130 23:52]:
> > Quoting Tony Lindgren (2018-11-30 07:37:29)
> > > * Tero Kristo <t-kristo@ti.com> [181130 09:21]:
> > > > On 30/11/2018 09:57, Stephen Boyd wrote:
> > > ...
> > > 
> > > And that way it would just propagate to the parent clock
> > > domain driver and the clock framework does not need to know
> > > about clockdomains. A clockdomain could be just a genpd
> > > domain.
> > > 
> > > Or do you guys have better ideas?
> > > 
> > 
> > Wouldn't the device link in clk framework patches do this for you if we
> > had the RUNTIME_PM flag passed in. If this is about keeping the clock
> > controller active when a consumer device is using it then I think it may
> > work.
> 
> The consumer device stays active just fine with PM runtime
> calls. So yes, the problem is keeping a clock controller forced
> active for the period of consumer device reset. Other than
> that typically autoidle can be just kept enabled.
> 
> Below is a clarified suggested example usage if we wanted to
> use PM runtime on a clock controller device from a consumer
> device reset driver:
> 
> error = pm_runtime_get_dev()
> ...
> cdev = clk_get_device(clk);
> ...
> error = pm_runtime_get(cdev);
> ...
> /* Do the consumer device reset here */
> ...
> pm_runtime_put(cdev);
> pm_runtime_put(dev);
> 

Does the consumer reset use the reset framework or something else? If
the driver is using the reset framework, I would expect the reset
framework to _also_ have device links and keep the clock controller,
i.e. reset provider, active while the reset is being toggled. And this
assumes the reset controller and clock controller code is all rolled up
together in a single driver that can tell itself to deny idle for
certain clks that are associated with whatever resets they affect.
Tony Lindgren Dec. 4, 2018, 4:45 p.m. UTC | #13
* Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:
> On Mon, 3 Dec 2018 07:39:10 -0800
> Tony Lindgren <tony@atomide.com> wrote:
> > The consumer device stays active just fine with PM runtime
> > calls. So yes, the problem is keeping a clock controller forced
> > active for the period of consumer device reset. Other than
> > that typically autoidle can be just kept enabled.
> > 
> Are we still talking about the same problem? Maybe I am losing track
> here. Just to make sure. 
> The patch series was about disabling autoidle for devices which cannot
> work with it during normal operation. Not during reset or something
> like that. 
> Or is the keep-clock-active-during-reset just a requirement for bigger
> restructuring ideas?

Yeah there are two issues: The fix needed for the issue you brought up,
and also how to let a reset driver to block autoidle for reset.

Regards,

Tony
Andreas Kemnade Dec. 27, 2018, 8:12 p.m. UTC | #14
Hi,

On Tue, 4 Dec 2018 08:45:57 -0800
Tony Lindgren <tony@atomide.com> wrote:

> * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:
> > On Mon, 3 Dec 2018 07:39:10 -0800
> > Tony Lindgren <tony@atomide.com> wrote:  
> > > The consumer device stays active just fine with PM runtime
> > > calls. So yes, the problem is keeping a clock controller forced
> > > active for the period of consumer device reset. Other than
> > > that typically autoidle can be just kept enabled.
> > >   
> > Are we still talking about the same problem? Maybe I am losing track
> > here. Just to make sure. 
> > The patch series was about disabling autoidle for devices which cannot
> > work with it during normal operation. Not during reset or something
> > like that. 
> > Or is the keep-clock-active-during-reset just a requirement for bigger
> > restructuring ideas?  
> 
> Yeah there are two issues: The fix needed for the issue you brought up,
> and also how to let a reset driver to block autoidle for reset.
> 
Hmm, is this set now waiting for the famous "somebody" fixing all
the stuff?
What are currently visible symptoms for the driver not blocking
autoidle for reset? Maybe I can at least test something there. I have
also omap5 here.

Regards,
Andreas
Tony Lindgren Dec. 28, 2018, 8:02 p.m. UTC | #15
* Andreas Kemnade <andreas@kemnade.info> [181227 20:13]:
> Hi,
> 
> On Tue, 4 Dec 2018 08:45:57 -0800
> Tony Lindgren <tony@atomide.com> wrote:
> 
> > * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:
> > > On Mon, 3 Dec 2018 07:39:10 -0800
> > > Tony Lindgren <tony@atomide.com> wrote:  
> > > > The consumer device stays active just fine with PM runtime
> > > > calls. So yes, the problem is keeping a clock controller forced
> > > > active for the period of consumer device reset. Other than
> > > > that typically autoidle can be just kept enabled.
> > > >   
> > > Are we still talking about the same problem? Maybe I am losing track
> > > here. Just to make sure. 
> > > The patch series was about disabling autoidle for devices which cannot
> > > work with it during normal operation. Not during reset or something
> > > like that. 
> > > Or is the keep-clock-active-during-reset just a requirement for bigger
> > > restructuring ideas?  
> > 
> > Yeah there are two issues: The fix needed for the issue you brought up,
> > and also how to let a reset driver to block autoidle for reset.
> > 
> Hmm, is this set now waiting for the famous "somebody" fixing all
> the stuff?

Well I think we're still waiting on Tero to comment on this.

> What are currently visible symptoms for the driver not blocking
> autoidle for reset? Maybe I can at least test something there. I have
> also omap5 here.

Oh that's just for making drivers/reset drivers to work in
the long run. Let's keep that separate from these fixes..

Regards,

Tony
Tero Kristo Dec. 31, 2018, 7:23 a.m. UTC | #16
On 28/12/2018 22:02, Tony Lindgren wrote:
> * Andreas Kemnade <andreas@kemnade.info> [181227 20:13]:
>> Hi,
>>
>> On Tue, 4 Dec 2018 08:45:57 -0800
>> Tony Lindgren <tony@atomide.com> wrote:
>>
>>> * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:
>>>> On Mon, 3 Dec 2018 07:39:10 -0800
>>>> Tony Lindgren <tony@atomide.com> wrote:
>>>>> The consumer device stays active just fine with PM runtime
>>>>> calls. So yes, the problem is keeping a clock controller forced
>>>>> active for the period of consumer device reset. Other than
>>>>> that typically autoidle can be just kept enabled.
>>>>>    
>>>> Are we still talking about the same problem? Maybe I am losing track
>>>> here. Just to make sure.
>>>> The patch series was about disabling autoidle for devices which cannot
>>>> work with it during normal operation. Not during reset or something
>>>> like that.
>>>> Or is the keep-clock-active-during-reset just a requirement for bigger
>>>> restructuring ideas?
>>>
>>> Yeah there are two issues: The fix needed for the issue you brought up,
>>> and also how to let a reset driver to block autoidle for reset.
>>>
>> Hmm, is this set now waiting for the famous "somebody" fixing all
>> the stuff?
> 
> Well I think we're still waiting on Tero to comment on this.

The only item requiring immediate fixing is the point Stephen made out, 
removing the usage of CLK_IS_BASIC from this patch.

Afaics, the reset related concerns Tony has can be handled later.

-Tero

> 
>> What are currently visible symptoms for the driver not blocking
>> autoidle for reset? Maybe I can at least test something there. I have
>> also omap5 here.
> 
> Oh that's just for making drivers/reset drivers to work in
> the long run. Let's keep that separate from these fixes..
> 
> Regards,
> 
> Tony
> 
> 

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Andreas Kemnade Dec. 31, 2018, 8:30 a.m. UTC | #17
On Mon, 31 Dec 2018 09:23:01 +0200
Tero Kristo <t-kristo@ti.com> wrote:

> On 28/12/2018 22:02, Tony Lindgren wrote:
> > * Andreas Kemnade <andreas@kemnade.info> [181227 20:13]:  
> >> Hi,
> >>
> >> On Tue, 4 Dec 2018 08:45:57 -0800
> >> Tony Lindgren <tony@atomide.com> wrote:
> >>  
> >>> * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:  
> >>>> On Mon, 3 Dec 2018 07:39:10 -0800
> >>>> Tony Lindgren <tony@atomide.com> wrote:  
> >>>>> The consumer device stays active just fine with PM runtime
> >>>>> calls. So yes, the problem is keeping a clock controller forced
> >>>>> active for the period of consumer device reset. Other than
> >>>>> that typically autoidle can be just kept enabled.
> >>>>>      
> >>>> Are we still talking about the same problem? Maybe I am losing track
> >>>> here. Just to make sure.
> >>>> The patch series was about disabling autoidle for devices which cannot
> >>>> work with it during normal operation. Not during reset or something
> >>>> like that.
> >>>> Or is the keep-clock-active-during-reset just a requirement for bigger
> >>>> restructuring ideas?  
> >>>
> >>> Yeah there are two issues: The fix needed for the issue you brought up,
> >>> and also how to let a reset driver to block autoidle for reset.
> >>>  
> >> Hmm, is this set now waiting for the famous "somebody" fixing all
> >> the stuff?  
> > 
> > Well I think we're still waiting on Tero to comment on this.  
> 
> The only item requiring immediate fixing is the point Stephen made out, 
> removing the usage of CLK_IS_BASIC from this patch.
> 
> Afaics, the reset related concerns Tony has can be handled later.
> 
hmm, and there we need Stephen's opinion about having the allow/deny
autoidle functions in the main clk_ops struct.

Regards,
Andreas
Stephen Boyd Jan. 3, 2019, 11:39 p.m. UTC | #18
Quoting Andreas Kemnade (2018-12-31 00:30:21)
> On Mon, 31 Dec 2018 09:23:01 +0200
> Tero Kristo <t-kristo@ti.com> wrote:
> 
> > On 28/12/2018 22:02, Tony Lindgren wrote:
> > > * Andreas Kemnade <andreas@kemnade.info> [181227 20:13]:  
> > >> Hi,
> > >>
> > >> On Tue, 4 Dec 2018 08:45:57 -0800
> > >> Tony Lindgren <tony@atomide.com> wrote:
> > >>  
> > >>> * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:  
> > >>>> On Mon, 3 Dec 2018 07:39:10 -0800
> > >>>> Tony Lindgren <tony@atomide.com> wrote:  
> > >>>>> The consumer device stays active just fine with PM runtime
> > >>>>> calls. So yes, the problem is keeping a clock controller forced
> > >>>>> active for the period of consumer device reset. Other than
> > >>>>> that typically autoidle can be just kept enabled.
> > >>>>>      
> > >>>> Are we still talking about the same problem? Maybe I am losing track
> > >>>> here. Just to make sure.
> > >>>> The patch series was about disabling autoidle for devices which cannot
> > >>>> work with it during normal operation. Not during reset or something
> > >>>> like that.
> > >>>> Or is the keep-clock-active-during-reset just a requirement for bigger
> > >>>> restructuring ideas?  
> > >>>
> > >>> Yeah there are two issues: The fix needed for the issue you brought up,
> > >>> and also how to let a reset driver to block autoidle for reset.
> > >>>  
> > >> Hmm, is this set now waiting for the famous "somebody" fixing all
> > >> the stuff?  
> > > 
> > > Well I think we're still waiting on Tero to comment on this.  
> > 
> > The only item requiring immediate fixing is the point Stephen made out, 
> > removing the usage of CLK_IS_BASIC from this patch.
> > 
> > Afaics, the reset related concerns Tony has can be handled later.
> > 
> hmm, and there we need Stephen's opinion about having the allow/deny
> autoidle functions in the main clk_ops struct.
> 

I have unanswered questions on the list for this thread[1]. I'm not sure
what allow/deny autoidle functions mean to clk drivers. It looks like an
OMAP specific addition to the clk_ops struct, which sounds wrong to put
it plainly. Hopefully it can be done outside of the clk framework by
having the provider driver know more things about all the frameworks
it's hooking into.

[1] https://lkml.kernel.org/r/154385676593.88331.5239924154783168815@swboyd.mtv.corp.google.com
Tero Kristo Jan. 4, 2019, 7:28 a.m. UTC | #19
On 04/01/2019 01:39, Stephen Boyd wrote:
> Quoting Andreas Kemnade (2018-12-31 00:30:21)
>> On Mon, 31 Dec 2018 09:23:01 +0200
>> Tero Kristo <t-kristo@ti.com> wrote:
>>
>>> On 28/12/2018 22:02, Tony Lindgren wrote:
>>>> * Andreas Kemnade <andreas@kemnade.info> [181227 20:13]:
>>>>> Hi,
>>>>>
>>>>> On Tue, 4 Dec 2018 08:45:57 -0800
>>>>> Tony Lindgren <tony@atomide.com> wrote:
>>>>>   
>>>>>> * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:
>>>>>>> On Mon, 3 Dec 2018 07:39:10 -0800
>>>>>>> Tony Lindgren <tony@atomide.com> wrote:
>>>>>>>> The consumer device stays active just fine with PM runtime
>>>>>>>> calls. So yes, the problem is keeping a clock controller forced
>>>>>>>> active for the period of consumer device reset. Other than
>>>>>>>> that typically autoidle can be just kept enabled.
>>>>>>>>       
>>>>>>> Are we still talking about the same problem? Maybe I am losing track
>>>>>>> here. Just to make sure.
>>>>>>> The patch series was about disabling autoidle for devices which cannot
>>>>>>> work with it during normal operation. Not during reset or something
>>>>>>> like that.
>>>>>>> Or is the keep-clock-active-during-reset just a requirement for bigger
>>>>>>> restructuring ideas?
>>>>>>
>>>>>> Yeah there are two issues: The fix needed for the issue you brought up,
>>>>>> and also how to let a reset driver to block autoidle for reset.
>>>>>>   
>>>>> Hmm, is this set now waiting for the famous "somebody" fixing all
>>>>> the stuff?
>>>>
>>>> Well I think we're still waiting on Tero to comment on this.
>>>
>>> The only item requiring immediate fixing is the point Stephen made out,
>>> removing the usage of CLK_IS_BASIC from this patch.
>>>
>>> Afaics, the reset related concerns Tony has can be handled later.
>>>
>> hmm, and there we need Stephen's opinion about having the allow/deny
>> autoidle functions in the main clk_ops struct.
>>
> 
> I have unanswered questions on the list for this thread[1].

The reset portion we can't answer with the current knowledge I fear, we 
need to prototype this a bit first and see which way to go.

> I'm not sure
> what allow/deny autoidle functions mean to clk drivers. It looks like an
> OMAP specific addition to the clk_ops struct, which sounds wrong to put
> it plainly.

Yeah, I don't think other SoCs implement the same functionality, at 
least not in the same way. The autoidle bits are available in 
omap2/omap3 only, where they control the HW autoidle functionality of 
these clocks. If the bit is enabled, the HW can autonomously disable the 
clock once it is not needed anymore by HW.

> Hopefully it can be done outside of the clk framework by
> having the provider driver know more things about all the frameworks
> it's hooking into.

This is how it has been done so far, however Andreas wants to expand the 
functionality a bit where it breaks... unless we can use the 
CLK_IS_BASIC flag to detect if we accessing an OMAP specific clock or 
not. If we are passing in a clk pointer from a consumer level API, I 
don't know if there is any other way to go with this if we can't modify 
the generic clk_ops struct.

The same flag check is used across TI clock driver already btw.

-Tero

> 
> [1] https://lkml.kernel.org/r/154385676593.88331.5239924154783168815@swboyd.mtv.corp.google.com
> 

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Stephen Boyd Jan. 11, 2019, 10:49 p.m. UTC | #20
Quoting Tero Kristo (2019-01-03 23:28:58)
> On 04/01/2019 01:39, Stephen Boyd wrote:
> > Quoting Andreas Kemnade (2018-12-31 00:30:21)
> >> On Mon, 31 Dec 2018 09:23:01 +0200
> >> Tero Kristo <t-kristo@ti.com> wrote:
> >>
> >>> On 28/12/2018 22:02, Tony Lindgren wrote:
> >>>> * Andreas Kemnade <andreas@kemnade.info> [181227 20:13]:
> >>>>> Hi,
> >>>>>
> >>>>> On Tue, 4 Dec 2018 08:45:57 -0800
> >>>>> Tony Lindgren <tony@atomide.com> wrote:
> >>>>>   
> >>>>>> * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:
> >>>>>>> On Mon, 3 Dec 2018 07:39:10 -0800
> >>>>>>> Tony Lindgren <tony@atomide.com> wrote:
> >>>>>>>> The consumer device stays active just fine with PM runtime
> >>>>>>>> calls. So yes, the problem is keeping a clock controller forced
> >>>>>>>> active for the period of consumer device reset. Other than
> >>>>>>>> that typically autoidle can be just kept enabled.
> >>>>>>>>       
> >>>>>>> Are we still talking about the same problem? Maybe I am losing track
> >>>>>>> here. Just to make sure.
> >>>>>>> The patch series was about disabling autoidle for devices which cannot
> >>>>>>> work with it during normal operation. Not during reset or something
> >>>>>>> like that.
> >>>>>>> Or is the keep-clock-active-during-reset just a requirement for bigger
> >>>>>>> restructuring ideas?
> >>>>>>
> >>>>>> Yeah there are two issues: The fix needed for the issue you brought up,
> >>>>>> and also how to let a reset driver to block autoidle for reset.
> >>>>>>   
> >>>>> Hmm, is this set now waiting for the famous "somebody" fixing all
> >>>>> the stuff?
> >>>>
> >>>> Well I think we're still waiting on Tero to comment on this.
> >>>
> >>> The only item requiring immediate fixing is the point Stephen made out,
> >>> removing the usage of CLK_IS_BASIC from this patch.
> >>>
> >>> Afaics, the reset related concerns Tony has can be handled later.
> >>>
> >> hmm, and there we need Stephen's opinion about having the allow/deny
> >> autoidle functions in the main clk_ops struct.
> >>
> > 
> > I have unanswered questions on the list for this thread[1].
> 
> The reset portion we can't answer with the current knowledge I fear, we 
> need to prototype this a bit first and see which way to go.
> 
> > I'm not sure
> > what allow/deny autoidle functions mean to clk drivers. It looks like an
> > OMAP specific addition to the clk_ops struct, which sounds wrong to put
> > it plainly.
> 
> Yeah, I don't think other SoCs implement the same functionality, at 
> least not in the same way. The autoidle bits are available in 
> omap2/omap3 only, where they control the HW autoidle functionality of 
> these clocks. If the bit is enabled, the HW can autonomously disable the 
> clock once it is not needed anymore by HW.

Some qcom chips have automatic clock gating (basically hw clk gating)
but they don't really need to involve that with the reset asserting or
deasserting anymore. It used to be that they had to turn off the
automatic mode, assert the reset, deassert the reset, and then reenable
the automatic mode. So there is some precedence for this. But again, I
think that the reset controller and the clk controller are the same
device in both vendor instances so in theory the driver can be one
driver for both clk and reset and do the proper things on the backend.
So just use reset controller framework and register that from the clk
controller driver?

> 
> > Hopefully it can be done outside of the clk framework by
> > having the provider driver know more things about all the frameworks
> > it's hooking into.
> 
> This is how it has been done so far, however Andreas wants to expand the 
> functionality a bit where it breaks... unless we can use the 
> CLK_IS_BASIC flag to detect if we accessing an OMAP specific clock or 
> not. If we are passing in a clk pointer from a consumer level API, I 
> don't know if there is any other way to go with this if we can't modify 
> the generic clk_ops struct.
> 
> The same flag check is used across TI clock driver already btw.
> 

Sure, it's not like this is a new problem. I'd just like to see if we
can solve it now and get rid of the CLK_IS_BASIC flag now. It would be
great if some extra effort could be put into it vs. punting the problem
until 2020 or something.
Tero Kristo Jan. 14, 2019, 8:25 a.m. UTC | #21
On 12/01/2019 00:49, Stephen Boyd wrote:
> Quoting Tero Kristo (2019-01-03 23:28:58)
>> On 04/01/2019 01:39, Stephen Boyd wrote:
>>> Quoting Andreas Kemnade (2018-12-31 00:30:21)
>>>> On Mon, 31 Dec 2018 09:23:01 +0200
>>>> Tero Kristo <t-kristo@ti.com> wrote:
>>>>
>>>>> On 28/12/2018 22:02, Tony Lindgren wrote:
>>>>>> * Andreas Kemnade <andreas@kemnade.info> [181227 20:13]:
>>>>>>> Hi,
>>>>>>>
>>>>>>> On Tue, 4 Dec 2018 08:45:57 -0800
>>>>>>> Tony Lindgren <tony@atomide.com> wrote:
>>>>>>>    
>>>>>>>> * Andreas Kemnade <andreas@kemnade.info> [181204 06:17]:
>>>>>>>>> On Mon, 3 Dec 2018 07:39:10 -0800
>>>>>>>>> Tony Lindgren <tony@atomide.com> wrote:
>>>>>>>>>> The consumer device stays active just fine with PM runtime
>>>>>>>>>> calls. So yes, the problem is keeping a clock controller forced
>>>>>>>>>> active for the period of consumer device reset. Other than
>>>>>>>>>> that typically autoidle can be just kept enabled.
>>>>>>>>>>        
>>>>>>>>> Are we still talking about the same problem? Maybe I am losing track
>>>>>>>>> here. Just to make sure.
>>>>>>>>> The patch series was about disabling autoidle for devices which cannot
>>>>>>>>> work with it during normal operation. Not during reset or something
>>>>>>>>> like that.
>>>>>>>>> Or is the keep-clock-active-during-reset just a requirement for bigger
>>>>>>>>> restructuring ideas?
>>>>>>>>
>>>>>>>> Yeah there are two issues: The fix needed for the issue you brought up,
>>>>>>>> and also how to let a reset driver to block autoidle for reset.
>>>>>>>>    
>>>>>>> Hmm, is this set now waiting for the famous "somebody" fixing all
>>>>>>> the stuff?
>>>>>>
>>>>>> Well I think we're still waiting on Tero to comment on this.
>>>>>
>>>>> The only item requiring immediate fixing is the point Stephen made out,
>>>>> removing the usage of CLK_IS_BASIC from this patch.
>>>>>
>>>>> Afaics, the reset related concerns Tony has can be handled later.
>>>>>
>>>> hmm, and there we need Stephen's opinion about having the allow/deny
>>>> autoidle functions in the main clk_ops struct.
>>>>
>>>
>>> I have unanswered questions on the list for this thread[1].
>>
>> The reset portion we can't answer with the current knowledge I fear, we
>> need to prototype this a bit first and see which way to go.
>>
>>> I'm not sure
>>> what allow/deny autoidle functions mean to clk drivers. It looks like an
>>> OMAP specific addition to the clk_ops struct, which sounds wrong to put
>>> it plainly.
>>
>> Yeah, I don't think other SoCs implement the same functionality, at
>> least not in the same way. The autoidle bits are available in
>> omap2/omap3 only, where they control the HW autoidle functionality of
>> these clocks. If the bit is enabled, the HW can autonomously disable the
>> clock once it is not needed anymore by HW.
> 
> Some qcom chips have automatic clock gating (basically hw clk gating)
> but they don't really need to involve that with the reset asserting or
> deasserting anymore. It used to be that they had to turn off the
> automatic mode, assert the reset, deassert the reset, and then reenable
> the automatic mode. So there is some precedence for this. But again, I
> think that the reset controller and the clk controller are the same
> device in both vendor instances so in theory the driver can be one
> driver for both clk and reset and do the proper things on the backend.
> So just use reset controller framework and register that from the clk
> controller driver?
> 
>>
>>> Hopefully it can be done outside of the clk framework by
>>> having the provider driver know more things about all the frameworks
>>> it's hooking into.
>>
>> This is how it has been done so far, however Andreas wants to expand the
>> functionality a bit where it breaks... unless we can use the
>> CLK_IS_BASIC flag to detect if we accessing an OMAP specific clock or
>> not. If we are passing in a clk pointer from a consumer level API, I
>> don't know if there is any other way to go with this if we can't modify
>> the generic clk_ops struct.
>>
>> The same flag check is used across TI clock driver already btw.
>>
> 
> Sure, it's not like this is a new problem. I'd just like to see if we
> can solve it now and get rid of the CLK_IS_BASIC flag now. It would be
> great if some extra effort could be put into it vs. punting the problem
> until 2020 or something.

Ok, let me see if I can figure out something for this...

-Tero
--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
diff mbox series

Patch

diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
index 161f67850393..5bdae5552d38 100644
--- a/drivers/clk/ti/autoidle.c
+++ b/drivers/clk/ti/autoidle.c
@@ -54,8 +54,12 @@  static DEFINE_SPINLOCK(autoidle_spinlock);
 int omap2_clk_deny_idle(struct clk *clk)
 {
 	struct clk_hw_omap *c;
+	struct clk_hw *hw = __clk_get_hw(clk);
 
-	c = to_clk_hw_omap(__clk_get_hw(clk));
+	if (clk_hw_get_flags(hw) & CLK_IS_BASIC)
+		return -EINVAL;
+
+	c = to_clk_hw_omap(hw);
 	if (c->ops && c->ops->deny_idle) {
 		unsigned long irqflags;
 
@@ -77,8 +81,12 @@  int omap2_clk_deny_idle(struct clk *clk)
 int omap2_clk_allow_idle(struct clk *clk)
 {
 	struct clk_hw_omap *c;
+	struct clk_hw *hw = __clk_get_hw(clk);
 
-	c = to_clk_hw_omap(__clk_get_hw(clk));
+	if (clk_hw_get_flags(hw) & CLK_IS_BASIC)
+		return -EINVAL;
+
+	c = to_clk_hw_omap(hw);
 	if (c->ops && c->ops->allow_idle) {
 		unsigned long irqflags;