Gentoo Archives: gentoo-embedded

From: Natanael Copa <natanael.copa@×××××.com>
To: gentoo-embedded@l.g.o
Subject: Re: [gentoo-embedded] writing device drivers howto
Date: Tue, 22 Aug 2006 14:03:45
Message-Id: 1156255372.17633.43.camel@localhost
In Reply to: [gentoo-embedded] writing device drivers howto by andreas.sumper@cnsystems.at
1 On Tue, 2006-08-22 at 15:37 +0200, andreas.sumper@×××××××××.at wrote:
2 >
3 > Hi list!
4 >
5 > This is some sort of offtopic, but I guess this is the best point to
6 > ask.
7 > I have an embedded system running linux. I need to access some special
8 > registers (e.g. containing the clock cycles, ...) So I managed to
9 > write a very simple module, which is able to access the registers. But
10 > what makes me worrying now, is the way, I have to get the data into my
11 > user-space application. Is there some documentation, concerning
12 > writing device drivers and accessing them from the user space
13 > anywhere? I found some documentation, but either I did not understand
14 > the part about getting data from kernel space into user space, or it
15 > was just simply missing.
16 >
17 > Maybe anyone here can help me out!
18 >
19 > Thanks in advance and kind regards!
20 >
21
22 I don't have much experience with kernel development but I think you
23 need a device in /dev that you can control with ioctl to communicate
24 with the module.
25
26 I looked into how to access the md5/sha1/sha256 kernel modules and I
27 concluded that a /dev/crypto was needed. Someone had made a patch for it
28 but it doesn look like it will go into main kernel so I gave it up.
29
30 You can look how he did. google for cryptodev.
31
32 > Bye,
33 > Andy
34
35 --
36 Natanael Copa
37
38 --
39 gentoo-embedded@g.o mailing list