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[RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change()

Started by<jiada_wang@mentor.com>
First post2016-07-11 07:40 +0200
Last post2016-07-14 07:20 +0200
Articles 3 — 3 participants

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  [RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change() <jiada_wang@mentor.com> - 2016-07-11 07:40 +0200
    Re: [RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to  clk_propagate_rate_change() Michael Turquette <mturquette@baylibre.com> - 2016-07-13 00:40 +0200
      Re: [RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change() Jiada Wang <jiada_wang@mentor.com> - 2016-07-14 07:20 +0200

#1440259 — [RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change()

From<jiada_wang@mentor.com>
Date2016-07-11 07:40 +0200
Subject[RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change()
Message-ID<rTC6J-2Oh-11@gated-at.bofh.it>
From: Jiada Wang <jiada_wang@mentor.com>

Previously CLK_SET_RATE_GATE flag is only checked in clk_set_rate()
which only ensures the clock being called by clk_set_rate() won't
change rate when it has been prepared if CLK_SET_RATE_GATE flag is set.
But a clk_set_rate() request may propagate rate change to these clocks
from the requested clock's topmost parent clock to all its offsprings,
when any one of these clocks has CLK_SET_RATE_GATE flag set
and it has been prepared, the clk_set_rate() request should fail.

This patch moves check of CLK_SET_RATE_GATE flag to
clk_propagate_rate_change() to ensure all affected clocks will
be checked if their rate will be changed after clk_set_rate().

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
---
 drivers/clk/clk.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 820a939..2f930c8 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1437,6 +1437,9 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
 	if (core->rate == core->new_rate)
 		return NULL;
 
+	if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
+		return core;
+
 	if (core->notifier_count) {
 		ret = __clk_notify(core, event, core->rate, core->new_rate);
 		if (ret & NOTIFY_STOP_MASK)
@@ -1571,9 +1574,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
 	if (rate == clk_core_get_rate_nolock(core))
 		return 0;
 
-	if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
-		return -EBUSY;
-
 	/* calculate new rates and get the topmost changed clock */
 	top = clk_calc_new_rates(core, rate);
 	if (!top)
-- 
1.7.9.5

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#1441811 — Re: [RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change()

FromMichael Turquette <mturquette@baylibre.com>
Date2016-07-13 00:40 +0200
SubjectRe: [RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change()
Message-ID<rUevn-2IR-1@gated-at.bofh.it>
In reply to#1440259
Quoting jiada_wang@mentor.com (2016-07-10 22:33:28)
> From: Jiada Wang <jiada_wang@mentor.com>
> 
> Previously CLK_SET_RATE_GATE flag is only checked in clk_set_rate()
> which only ensures the clock being called by clk_set_rate() won't
> change rate when it has been prepared if CLK_SET_RATE_GATE flag is set.
> But a clk_set_rate() request may propagate rate change to these clocks
> from the requested clock's topmost parent clock to all its offsprings,
> when any one of these clocks has CLK_SET_RATE_GATE flag set
> and it has been prepared, the clk_set_rate() request should fail.
> 
> This patch moves check of CLK_SET_RATE_GATE flag to
> clk_propagate_rate_change() to ensure all affected clocks will
> be checked if their rate will be changed after clk_set_rate().
> 
> Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
> ---

What's different in version 2? It's tradition to put a little version
changelog here, below the "---" line and above the "diff --git a/..."
line.

Regards,
Mike

>  drivers/clk/clk.c |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 820a939..2f930c8 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1437,6 +1437,9 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
>         if (core->rate == core->new_rate)
>                 return NULL;
>  
> +       if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
> +               return core;
> +
>         if (core->notifier_count) {
>                 ret = __clk_notify(core, event, core->rate, core->new_rate);
>                 if (ret & NOTIFY_STOP_MASK)
> @@ -1571,9 +1574,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
>         if (rate == clk_core_get_rate_nolock(core))
>                 return 0;
>  
> -       if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
> -               return -EBUSY;
> -
>         /* calculate new rates and get the topmost changed clock */
>         top = clk_calc_new_rates(core, rate);
>         if (!top)
> -- 
> 1.7.9.5
> 
>

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#1443071

FromJiada Wang <jiada_wang@mentor.com>
Date2016-07-14 07:20 +0200
Message-ID<rUHe1-5dl-9@gated-at.bofh.it>
In reply to#1441811
Hello Michael

On 07/13/2016 07:29 AM, Michael Turquette wrote:
> Quoting jiada_wang@mentor.com (2016-07-10 22:33:28)
>> From: Jiada Wang <jiada_wang@mentor.com>
>>
>> Previously CLK_SET_RATE_GATE flag is only checked in clk_set_rate()
>> which only ensures the clock being called by clk_set_rate() won't
>> change rate when it has been prepared if CLK_SET_RATE_GATE flag is set.
>> But a clk_set_rate() request may propagate rate change to these clocks
>> from the requested clock's topmost parent clock to all its offsprings,
>> when any one of these clocks has CLK_SET_RATE_GATE flag set
>> and it has been prepared, the clk_set_rate() request should fail.
>>
>> This patch moves check of CLK_SET_RATE_GATE flag to
>> clk_propagate_rate_change() to ensure all affected clocks will
>> be checked if their rate will be changed after clk_set_rate().
>>
>> Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
>> ---
>
> What's different in version 2? It's tradition to put a little version
> changelog here, below the "---" line and above the "diff --git a/..."
> line.
>
version 2 resolves the following kernel warning
"
    drivers/clk/clk.c: In function 'clk_propagate_rate_change':
 >> drivers/clk/clk.c:1441:3: warning: return makes pointer from integer 
without a cast
       return -EBUSY;
       ^
"
I forgot to add a changelog in v2 patch, sorry for the confusion caused.

Thanks,
Jiada
> Regards,
> Mike
>
>>   drivers/clk/clk.c |    6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
>> index 820a939..2f930c8 100644
>> --- a/drivers/clk/clk.c
>> +++ b/drivers/clk/clk.c
>> @@ -1437,6 +1437,9 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
>>          if (core->rate == core->new_rate)
>>                  return NULL;
>>
>> +       if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
>> +               return core;
>> +
>>          if (core->notifier_count) {
>>                  ret = __clk_notify(core, event, core->rate, core->new_rate);
>>                  if (ret & NOTIFY_STOP_MASK)
>> @@ -1571,9 +1574,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
>>          if (rate == clk_core_get_rate_nolock(core))
>>                  return 0;
>>
>> -       if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
>> -               return -EBUSY;
>> -
>>          /* calculate new rates and get the topmost changed clock */
>>          top = clk_calc_new_rates(core, rate);
>>          if (!top)
>> --
>> 1.7.9.5
>>
>>

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