Re: How to introduce omap_features (was Re: [PATCH RESEND] update omap3 features bitmap and API to generic names)

2010-05-11 Thread Venkatraman S 
On Tue, May 11, 2010 at 7:13 PM, Nishanth Menon  wrote:
> Venkatraman S had written, on 05/11/2010 07:19 AM, the following:
>>
>>  Nishanth Menon  wrote:
>>>
>>> -linux-arm
>>>
>>> On 05/10/2010 10:53 PM, S, Venkatraman wrote:
>
> -Original Message-
> From: menon.nisha...@gmail.com
> [mailto:menon.nisha...@gmail.com] On Behalf Of Menon, Nishanth
> Sent: Tuesday, May 11, 2010 5:02 AM
> To: S, Venkatraman
> Cc: linux-omap@vger.kernel.org;
> linux-arm-ker...@lists.infradead.org; Tony Lindgren;
> Chikkature Rajashekar, Madhusudhan
> Subject: Re: [PATCH RESEND] update omap3 features bitmap and
> API to generic names
>
> On Mon, May 10, 2010 at 2:55 PM, Venkatraman S
>   wrote:
>>
>>       OMAP3 features bitmap is used a method to check for SoC
>> specific features. This patch renames the global variables and the
>> accessor functions to use a generic name from omap3_* to
>> omap_*
>>
>> Signed-off-by: Venkatraman S
>> CC: Nishant Menon
>
> Just for the patchworks
> NAK - discussed before -
> http://marc.info/?l=linux-omap&m=127349696800651&w=2

 This patch doesn't have the descriptor load changes, and just the
 rename.
 Did you take a look at it first?
>>>
>>> Arrgh - my bad - there was no reference to previous discussions or
>>> anything
>>> in this patch, please do add references in diffstat section if you are
>>> refering to a previous discussed strategy to help the reviewers
>>> differentiate and understand you better.
>>>
>>> overall this still opens up a question for me -> can we blindly replace
>>> omap3-features with omap features? how do we think of omap1,2,3,4 are
>>> handled consistently with a 32 bit field?
>>>
>>> I agree on the need to have a omap independent field, but is
>>> omap3_features
>>> the one we need to modify OR should we be introducing a new field?
>>>
>>> my vote goes for introducing a new field.
>>>
>>
>> You are confusing the interface with implementation (or rather,
>> worrying about both of them simultaneously).
>>
>> The interface has to be consistent and SoC independent, to the extent
>> possible.
>>  So the macro changes are relevant and readable / extensible.
>>
>> Regarding the variable name (implementation):-
>>   Given the minimal set that we have (5 -6 fields today, so there is
>> room for 25 more 'features" still), I don't think
>> we should over-engineer it now to accomodate all permutations and use
>> cases. It's not even found use
>> beyond 1 or 2 files. YAGNI ?
>
> huh? I dont understand you. lets see what we we are doing here:
> a) we are causing an ABI breakage by moving omap3_feature to omap_feature


The omap3_feature variable is not supposed to be used by modules
*querying* for the feature. They don't even have to know it's existence.
 That is what the macros/inline functions  omap_has_***() are for.

All the uses of omap3_has_** have been replaced by omap_has_** in this patch.
This is an ABI change (due to the previous interface tying it to OMAP3)
and *not* ABI breakage (All previous uses have been replaced)

> (which by the way should also include changes to the macros as well..)
This is different. There could be different ways in which the
actual snooping
of whether a feature exists on not is implemented. For OMAP3, it is
looking up the control module.
(This, I have preserved). For other SoCs, it could be different, I
don't know how to
snoop them for. Your comments are welcome.

> b) we have a real need to have a cross OMAP feature distinction to
> differentiate between generic omap feature and omap3/2/1/4 features.
>
> This patch does not address the same in a consistent scalable way. NOTE: we
> are starting to introduce other OMAP4 features as well, SOC level feature
> distinction should ideally be handled by FEATURE framework - that is the
> reason it was introduced in the first place.

 I never claimed this patch to be a mother of all 'features
framework'. It was just
a name improvement to the bunch of macros that existed. Again,

a) it preserves the separtion of interface. We can have a full fledged tree
   of generic / OMAP[12345] specific features, but the interface need not
change.

>
> if your feel this is overengineering - well, I believe this is conceptual
> definition -> Specific OMAP[1234] *family* features Vs OMAP generic
> features.. two different things in my mind -> it does not matter if I have
> 32 bits in the original variable OR if I had 64bit.. i dont prefer to reuse
> a variable and mess up the conceptual distinction.
>

b) Are you simply saying that the existing features bitmap (all 6 of
them) are tied to OMAP3 ? For good ?
In that case, I really understand your comments and can change back
the variable name.

At the same time, it's not easy to classify what category a feature belongs to.
What could a single SoC specific feature today (SDMA descriptor
loading) could then become
a series (OMAP4, OMAP5 etc).

Re: How to introduce omap_features (was Re: [PATCH RESEND] update omap3 features bitmap and API to generic names)

2010-05-11 Thread Nishanth Menon 

Venkatraman S had written, on 05/11/2010 07:19 AM, the following:

 Nishanth Menon  wrote:

-linux-arm

On 05/10/2010 10:53 PM, S, Venkatraman wrote:

-Original Message-
From: menon.nisha...@gmail.com
[mailto:menon.nisha...@gmail.com] On Behalf Of Menon, Nishanth
Sent: Tuesday, May 11, 2010 5:02 AM
To: S, Venkatraman
Cc: linux-omap@vger.kernel.org;
linux-arm-ker...@lists.infradead.org; Tony Lindgren;
Chikkature Rajashekar, Madhusudhan
Subject: Re: [PATCH RESEND] update omap3 features bitmap and
API to generic names

On Mon, May 10, 2010 at 2:55 PM, Venkatraman S
  wrote:

   OMAP3 features bitmap is used a method to check for SoC
specific features. This patch renames the global variables and the
accessor functions to use a generic name from omap3_* to
omap_*

Signed-off-by: Venkatraman S
CC: Nishant Menon

Just for the patchworks
NAK - discussed before -
http://marc.info/?l=linux-omap&m=127349696800651&w=2

This patch doesn't have the descriptor load changes, and just the rename.
Did you take a look at it first?

Arrgh - my bad - there was no reference to previous discussions or anything
in this patch, please do add references in diffstat section if you are
refering to a previous discussed strategy to help the reviewers
differentiate and understand you better.

overall this still opens up a question for me -> can we blindly replace
omap3-features with omap features? how do we think of omap1,2,3,4 are
handled consistently with a 32 bit field?

I agree on the need to have a omap independent field, but is omap3_features
the one we need to modify OR should we be introducing a new field?

my vote goes for introducing a new field.



You are confusing the interface with implementation (or rather,
worrying about both of them simultaneously).

The interface has to be consistent and SoC independent, to the extent possible.
  So the macro changes are relevant and readable / extensible.

Regarding the variable name (implementation):-
   Given the minimal set that we have (5 -6 fields today, so there is
room for 25 more 'features" still), I don't think
we should over-engineer it now to accomodate all permutations and use
cases. It's not even found use
beyond 1 or 2 files. YAGNI ?


huh? I dont understand you. lets see what we we are doing here:
a) we are causing an ABI breakage by moving omap3_feature to 
omap_feature (which by the way should also include changes to the macros 
as well..)
b) we have a real need to have a cross OMAP feature distinction to 
differentiate between generic omap feature and omap3/2/1/4 features.


This patch does not address the same in a consistent scalable way. NOTE: 
we are starting to introduce other OMAP4 features as well, SOC level 
feature distinction should ideally be handled by FEATURE framework - 
that is the reason it was introduced in the first place.


if your feel this is overengineering - well, I believe this is 
conceptual definition -> Specific OMAP[1234] *family* features Vs OMAP 
generic features.. two different things in my mind -> it does not matter 
if I have 32 bits in the original variable OR if I had 64bit.. i dont 
prefer to reuse a variable and mess up the conceptual distinction.



--
Regards,
Nishanth Menon
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Re: How to introduce omap_features (was Re: [PATCH RESEND] update omap3 features bitmap and API to generic names)

2010-05-11 Thread Venkatraman S 
 Nishanth Menon  wrote:
> -linux-arm
>
> On 05/10/2010 10:53 PM, S, Venkatraman wrote:
>>>
>>> -Original Message-
>>> From: menon.nisha...@gmail.com
>>> [mailto:menon.nisha...@gmail.com] On Behalf Of Menon, Nishanth
>>> Sent: Tuesday, May 11, 2010 5:02 AM
>>> To: S, Venkatraman
>>> Cc: linux-omap@vger.kernel.org;
>>> linux-arm-ker...@lists.infradead.org; Tony Lindgren;
>>> Chikkature Rajashekar, Madhusudhan
>>> Subject: Re: [PATCH RESEND] update omap3 features bitmap and
>>> API to generic names
>>>
>>> On Mon, May 10, 2010 at 2:55 PM, Venkatraman S
>>>   wrote:

        OMAP3 features bitmap is used a method to check for SoC
 specific features. This patch renames the global variables and the
 accessor functions to use a generic name from omap3_* to
 omap_*

 Signed-off-by: Venkatraman S
 CC: Nishant Menon
>>>
>>> Just for the patchworks
>>> NAK - discussed before -
>>> http://marc.info/?l=linux-omap&m=127349696800651&w=2
>>
>> This patch doesn't have the descriptor load changes, and just the rename.
>> Did you take a look at it first?
>
> Arrgh - my bad - there was no reference to previous discussions or anything
> in this patch, please do add references in diffstat section if you are
> refering to a previous discussed strategy to help the reviewers
> differentiate and understand you better.
>
> overall this still opens up a question for me -> can we blindly replace
> omap3-features with omap features? how do we think of omap1,2,3,4 are
> handled consistently with a 32 bit field?
>
> I agree on the need to have a omap independent field, but is omap3_features
> the one we need to modify OR should we be introducing a new field?
>
> my vote goes for introducing a new field.
>

You are confusing the interface with implementation (or rather,
worrying about both of them simultaneously).

The interface has to be consistent and SoC independent, to the extent possible.
  So the macro changes are relevant and readable / extensible.

Regarding the variable name (implementation):-
   Given the minimal set that we have (5 -6 fields today, so there is
room for 25 more 'features" still), I don't think
we should over-engineer it now to accomodate all permutations and use
cases. It's not even found use
beyond 1 or 2 files. YAGNI ?

Regards,
Venkat.
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

How to introduce omap_features (was Re: [PATCH RESEND] update omap3 features bitmap and API to generic names)

2010-05-11 Thread Nishanth Menon 

-linux-arm

On 05/10/2010 10:53 PM, S, Venkatraman wrote:

-Original Message-
From: menon.nisha...@gmail.com
[mailto:menon.nisha...@gmail.com] On Behalf Of Menon, Nishanth
Sent: Tuesday, May 11, 2010 5:02 AM
To: S, Venkatraman
Cc: linux-omap@vger.kernel.org;
linux-arm-ker...@lists.infradead.org; Tony Lindgren;
Chikkature Rajashekar, Madhusudhan
Subject: Re: [PATCH RESEND] update omap3 features bitmap and
API to generic names

On Mon, May 10, 2010 at 2:55 PM, Venkatraman S
  wrote:

OMAP3 features bitmap is used a method to check for SoC
specific features. This patch renames the global variables and the
accessor functions to use a generic name from omap3_* to
omap_*

Signed-off-by: Venkatraman S
CC: Nishant Menon

Just for the patchworks
NAK - discussed before -
http://marc.info/?l=linux-omap&m=127349696800651&w=2


This patch doesn't have the descriptor load changes, and just the rename.
Did you take a look at it first?


Arrgh - my bad - there was no reference to previous discussions or 
anything in this patch, please do add references in diffstat section if 
you are refering to a previous discussed strategy to help the reviewers 
differentiate and understand you better.


overall this still opens up a question for me -> can we blindly replace 
omap3-features with omap features? how do we think of omap1,2,3,4 are 
handled consistently with a 32 bit field?


I agree on the need to have a omap independent field, but is 
omap3_features the one we need to modify OR should we be introducing a 
new field?


my vote goes for introducing a new field.




CC: Tony Lindgren
CC: Madhusudhan Chikkature
---
  * Resent to CC Madhu

  arch/arm/mach-omap2/clock3xxx_data.c  |2 +-
  arch/arm/mach-omap2/id.c  |   18 
  arch/arm/plat-omap/include/plat/cpu.h |   34

  3 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/arch/arm/mach-omap2/clock3xxx_data.c
b/arch/arm/mach-omap2/clock3xxx_data.c
index 9cba556..afa481d 100644
--- a/arch/arm/mach-omap2/clock3xxx_data.c
+++ b/arch/arm/mach-omap2/clock3xxx_data.c
@@ -3510,7 +3510,7 @@ int __init omap3xxx_clk_init(void)
cpu_clkflg |= CK_3430ES2;
}
}
-   if (omap3_has_192mhz_clk())
+   if (omap_has_192mhz_clk())
omap_96m_alwon_fck = omap_96m_alwon_fck_3630;

if (cpu_is_omap3630()) {
diff --git a/arch/arm/mach-omap2/id.c

b/arch/arm/mach-omap2/id.c index

37b8a1a..a095b87 100644
--- a/arch/arm/mach-omap2/id.c
+++ b/arch/arm/mach-omap2/id.c
@@ -28,7 +28,7 @@
  static struct omap_chip_id omap_chip;
  static unsigned int omap_revision;

-u32 omap3_features;
+u32 omap_features;

  unsigned int omap_rev(void)
  {
@@ -161,14 +161,14 @@ void __init omap24xx_check_revision(void)
  #define OMAP3_CHECK_FEATURE(status,feat)



\
if (((status&  OMAP3_ ##feat## _MASK)



\
>>  OMAP3_ ##feat## _SHIFT) != FEAT_ ##feat##

_NONE) {

\
-   omap3_features |= OMAP3_HAS_ ##feat;



\
+   omap_features |= OMAP_HAS_ ##feat;



+ \
}

  void __init omap3_check_features(void)
  {
u32 status;

-   omap3_features = 0;
+   omap_features = 0;

status = omap_ctrl_readl(OMAP3_CONTROL_OMAP_STATUS);

@@ -178,7 +178,7 @@ void __init omap3_check_features(void)
OMAP3_CHECK_FEATURE(status, NEON);
OMAP3_CHECK_FEATURE(status, ISP);
if (cpu_is_omap3630())
-   omap3_features |= OMAP3_HAS_192MHZ_CLK;
+   omap_features |= OMAP_HAS_192MHZ_CLK;

/*
 * TODO: Get additional info (where applicable) @@ -294,7
+294,7 @@ void __init omap4_check_revision(void)
  }

  #define OMAP3_SHOW_FEATURE(feat)   \
-   if (omap3_has_ ##feat())\
+   if (omap_has_ ##feat()) \
printk(#feat" ");

  void __init omap3_cpuinfo(void)
@@ -314,20 +314,20 @@ void __init omap3_cpuinfo(void)
/*
 * AM35xx devices
 */
-   if (omap3_has_sgx()) {
+   if (omap_has_sgx()) {
omap_revision = OMAP3517_REV(rev);
strcpy(cpu_name, "AM3517");
} else {
/* Already set in omap3_check_revision() */
strcpy(cpu_name, "AM3505");
}
-   } else if (omap3_has_iva()&&  omap3_has_sgx()) {
+   } else if (omap_has_iva()&&  omap_has_sgx()) {
/* OMAP3430, OMAP3525, OMAP3515, OMAP3503 devices */
strcpy(cpu_name, "OMAP3430/3530");
-   } else if (omap3_has_iva()) {
+   } else if (omap_has_iva()) {
omap_revision = OMAP3525_REV(rev);
strcpy(cpu_name, "OMAP3525");
-   } else if (omap3_has_sgx()) {
+   } else if (omap_has_sgx()) {
omap_revision = OMAP3515_REV(rev);
strcpy(cpu_name, "OMAP3515");
} else {