How to compile module params into kernel?

How to compile module params into kernel?

[Joakim Tjernlund]

Instead of passing a module param on the cmdline I want to compile that
into
the kernel, but I can't figure out how.

The module param I want compile into kernel is
rtc-ds1307.force=0,0x68

This is for an embeddet target that doesn't have loadable module
support.

 Thanks
      Jocke

Re: How to compile module params into kernel?

[Jesper Juhl]

On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> Instead of passing a module param on the cmdline I want to compile that
> into
> the kernel, but I can't figure out how.
>
> The module param I want compile into kernel is
> rtc-ds1307.force=0,0x68
>
> This is for an embeddet target that doesn't have loadable module
> support.
>
You could edit the module source and hardcode default values.

-- 
Jesper Juhl <jesper.juhl@gmail.com>
Don't top-post  http://www.catb.org/~esr/jargon/html/T/top-post.html
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RE: How to compile module params into kernel?

[Joakim Tjernlund]

> -----Original Message-----
> From: Jesper Juhl [mailto:jesper.juhl@gmail.com] 
> 
> On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > Instead of passing a module param on the cmdline I want to 
> compile that
> > into
> > the kernel, but I can't figure out how.
> >
> > The module param I want compile into kernel is
> > rtc-ds1307.force=0,0x68
> >
> > This is for an embeddet target that doesn't have loadable module
> > support.
> >
> You could edit the module source and hardcode default values.
> 

Yes, but I don't want to do that since it makes maintance
harder.

 Jocke

Re: How to compile module params into kernel?

[Jesper Juhl]

On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > -----Original Message-----
> > From: Jesper Juhl [mailto:jesper.juhl@gmail.com]
> >
> > On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > > Instead of passing a module param on the cmdline I want to
> > compile that
> > > into
> > > the kernel, but I can't figure out how.
> > >
> > > The module param I want compile into kernel is
> > > rtc-ds1307.force=0,0x68
> > >
> > > This is for an embeddet target that doesn't have loadable module
> > > support.
> > >
> > You could edit the module source and hardcode default values.
> >
>
> Yes, but I don't want to do that since it makes maintance
> harder.
>
Well, as far as I know, there's no way to specify default module
options at compile time. The defaults are set in the module source and
are modifiable at module load time or by setting options on the kernel
command line at boot tiem. So, if that's no good for you I don't see
any other way except modifying the source to hardcode new defaults.

-- 
Jesper Juhl <jesper.juhl@gmail.com>
Don't top-post  http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please      http://www.expita.com/nomime.html

Re: How to compile module params into kernel?

[Jan-Benedict Glaw]

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On Wed, 2006-11-08 21:09:04 +0100, Jesper Juhl <jesper.juhl@gmail.com> wrote:
> On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > > -----Original Message-----
> > > From: Jesper Juhl [mailto:jesper.juhl@gmail.com]
> > > On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > > > Instead of passing a module param on the cmdline I want to compile that
> > > > into the kernel, but I can't figure out how.
> > > You could edit the module source and hardcode default values.
> > Yes, but I don't want to do that since it makes maintance
> > harder.
> Well, as far as I know, there's no way to specify default module
> options at compile time. The defaults are set in the module source and
> are modifiable at module load time or by setting options on the kernel
> command line at boot tiem. So, if that's no good for you I don't see
> any other way except modifying the source to hardcode new defaults.

However, that could probably be hacked in easily. We use a similar
approach for VAX, since we're not yet regularly booting off a local
harddisk, but commonly via MOP off the network.

MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw@lug-owl.de              +49-172-7608481
Signature of:           Ich hatte in letzter Zeit ein bißchen viel Realitycheck.
the second  :               Langsam möchte ich mal wieder weiterträumen können.

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Re: How to compile module params into kernel?

[Miguel Ojeda]

On 11/8/06, Jesper Juhl <jesper.juhl@gmail.com> wrote:
> On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > > -----Original Message-----
> > > From: Jesper Juhl [mailto:jesper.juhl@gmail.com]
> > >
> > > On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > > > Instead of passing a module param on the cmdline I want to
> > > compile that
> > > > into
> > > > the kernel, but I can't figure out how.
> > > >
> > > > The module param I want compile into kernel is
> > > > rtc-ds1307.force=0,0x68
> > > >
> > > > This is for an embeddet target that doesn't have loadable module
> > > > support.
> > > >
> > > You could edit the module source and hardcode default values.
> > >
> >
> > Yes, but I don't want to do that since it makes maintance
> > harder.
> >
> Well, as far as I know, there's no way to specify default module
> options at compile time. The defaults are set in the module source and
> are modifiable at module load time or by setting options on the kernel
> command line at boot tiem. So, if that's no good for you I don't see
> any other way except modifying the source to hardcode new defaults.
>

You can add parameter values at Kconfig using "int", "hex"... instead
of tristate, and then do something like:

static unsigned int foo = CONFIG_foo;
module_param(foo, uint, S_IRUGO);
MODULE_PARM_DESC(foo, "foo value (uint)");

RE: How to compile module params into kernel?

[Joakim Tjernlund]

> -----Original Message-----
> From: Miguel Ojeda [mailto:maxextreme@gmail.com] 
> Sent: den 8 november 2006 21:17
> To: Jesper Juhl
> Cc: Joakim Tjernlund; linux-kernel@vger.kernel.org
> Subject: Re: How to compile module params into kernel?
> 
> On 11/8/06, Jesper Juhl <jesper.juhl@gmail.com> wrote:
> > On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > > > -----Original Message-----
> > > > From: Jesper Juhl [mailto:jesper.juhl@gmail.com]
> > > >
> > > > On 08/11/06, Joakim Tjernlund 
> <joakim.tjernlund@transmode.se> wrote:
> > > > > Instead of passing a module param on the cmdline I want to
> > > > compile that
> > > > > into
> > > > > the kernel, but I can't figure out how.
> > > > >
> > > > > The module param I want compile into kernel is
> > > > > rtc-ds1307.force=0,0x68
> > > > >
> > > > > This is for an embeddet target that doesn't have 
> loadable module
> > > > > support.
> > > > >
> > > > You could edit the module source and hardcode default values.
> > > >
> > >
> > > Yes, but I don't want to do that since it makes maintance
> > > harder.
> > >
> > Well, as far as I know, there's no way to specify default module
> > options at compile time. The defaults are set in the module 
> source and
> > are modifiable at module load time or by setting options on 
> the kernel
> > command line at boot tiem. So, if that's no good for you I don't see
> > any other way except modifying the source to hardcode new defaults.
> >
> 
> You can add parameter values at Kconfig using "int", "hex"... instead
> of tristate, and then do something like:
> 
> static unsigned int foo = CONFIG_foo;
> module_param(foo, uint, S_IRUGO);
> MODULE_PARM_DESC(foo, "foo value (uint)");

hmm, don't quite understand.
Can you rewrite that to match the cmdvar "rtc-ds1307.force=0,0x68" ? 

Re: How to compile module params into kernel?

[Richard B. Johnson]

----- Original Message ----- 
From: "Joakim Tjernlund" <joakim.tjernlund@transmode.se>
To: "'Jesper Juhl'" <jesper.juhl@gmail.com>
Cc: <linux-kernel@vger.kernel.org>
Sent: Wednesday, November 08, 2006 3:02 PM
Subject: RE: How to compile module params into kernel?


>> -----Original Message-----
>> From: Jesper Juhl [mailto:jesper.juhl@gmail.com]
>>
>> On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
>> > Instead of passing a module param on the cmdline I want to
>> compile that
>> > into
>> > the kernel, but I can't figure out how.
>> >
>> > The module param I want compile into kernel is
>> > rtc-ds1307.force=0,0x68
>> >
>> > This is for an embeddet target that doesn't have loadable module
>> > support.
>> >
>> You could edit the module source and hardcode default values.
>>
>
> Yes, but I don't want to do that since it makes maintance
> harder.
>
> Jocke
>
> -
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If you don't have a module, you can not use module parameters. However, it 
might even be simpler...
You just put your parameters (strings to parse) on the kernel command-line 
and you put code in your driver to interpret them.

You want to look at "saved_command_line." It is a string as:
extern char saved_command_line[COMMAND_LINE_SIZE];
You need to parse ASCII text yourself, in your driver, but it's trivial. 
Look at .../arch/i386/kernel/setup.c parse_cmdline_early().
I don't see anywhere in the kernel that it gets overwritten so it should be 
good to use.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 (somewhere). IT removed email  for 
engineers!
New Book: http://www.AbominableFirebug.com

Re: How to compile module params into kernel?

[Jan-Benedict Glaw]

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On Wed, 2006-11-08 15:59:44 -0500, Richard B. Johnson <jmodem@AbominableFirebug.com> wrote:
> If you don't have a module, you can not use module parameters. However, it 
> might even be simpler...

Well, you actually can!  If you've compiled something into your
kernel, you can use  <module name>.<parametername>=<value>  on your
kernel command line to set all the parameters you need.

MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw@lug-owl.de              +49-172-7608481
Signature of:                 Gib Dein Bestes. Dann übertriff Dich selbst!
the second  :

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Re: How to compile module params into kernel?

[Joakim Tjernlund]

Jan-Benedict Glaw wrote:
> On Wed, 2006-11-08 21:09:04 +0100, Jesper Juhl <jesper.juhl@gmail.com> wrote:
>   
>> On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
>>     
>>>> -----Original Message-----
>>>> From: Jesper Juhl [mailto:jesper.juhl@gmail.com]
>>>> On 08/11/06, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
>>>>         
>>>>> Instead of passing a module param on the cmdline I want to compile that
>>>>> into the kernel, but I can't figure out how.
>>>>>           
>>>> You could edit the module source and hardcode default values.
>>>>         
>>> Yes, but I don't want to do that since it makes maintance
>>> harder.
>>>       
>> Well, as far as I know, there's no way to specify default module
>> options at compile time. The defaults are set in the module source and
>> are modifiable at module load time or by setting options on the kernel
>> command line at boot tiem. So, if that's no good for you I don't see
>> any other way except modifying the source to hardcode new defaults.
>>     
>
> However, that could probably be hacked in easily. We use a similar
> approach for VAX, since we're not yet regularly booting off a local
> harddisk, but commonly via MOP off the network.
>
> MfG, JBG
>
>   
This works for me in should want to known:

#include <linux/moduleparam.h>
int set_module_params(void)
{
   extern struct kernel_param __start___param[], __stop___param[];
   char module_params[]="rtc-ds1307.force=0,0x68";

   parse_args("hard module params", module_params, __start___param,
          __stop___param - __start___param, NULL);
   return 0;
}
arch_initcall(set_module_params);