Re: [gentoo-embedded] writing device drivers howto

[Natanael Copa <natanael.copa@gmail.com>]

On Tue, 2006-08-22 at 15:37 +0200, andreas.sumper@cnsystems.at wrote:
> 
> Hi list! 
> 
> This is some sort of offtopic, but I guess this is the best point to
> ask.
> I have an embedded system running linux. I need to access some special
> registers (e.g. containing the clock cycles, ...) So I managed to
> write a very simple module, which is able to access the registers. But
> what makes me worrying now, is the way, I have to get the data into my
> user-space application. Is there some documentation, concerning
> writing device drivers and accessing them from the user space
> anywhere? I found some documentation, but either I did not understand
> the part about getting data from kernel space into user space, or it
> was just simply missing. 
> 
> Maybe anyone here can help me out! 
> 
> Thanks in advance and kind regards! 
> 

I don't have much experience with kernel development but I think you
need a device in /dev that you can control with ioctl to communicate
with the module.

I looked into how to access the md5/sha1/sha256 kernel modules and I
concluded that a /dev/crypto was needed. Someone had made a patch for it
but it doesn look like it will go into main kernel so I gave it up.

You can look how he did. google for cryptodev.

> Bye, 
> Andy

--
Natanael Copa

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