linux-kernel - Re: How to access correctly serial port inside module?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 06 Jun 2007 10:27:04 +0200
From:	"Lars K.W. Gohlke" <lkwg82@....de>
To:	Tilman Schmidt <tilman@...p.cc>
CC:	huang ying <huang.ying.caritas@...il.com>,
	Jan Engelhardt <jengelh@...ux01.gwdg.de>,
	linux-kernel@...r.kernel.org
Subject: Re: How to access correctly serial port inside module?

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Tilman Schmidt schrieb:
> Am 03.06.2007 22:28 schrieb Lars K.W. Gohlke:
>> Tilman Schmidt schrieb:
>>> Am 17.05.2007 08:15 schrieb huang ying:
>>>> I think the "serio" (through drivers/input/serio/serport.c) may be a
>>>> choice too, like that in linux/drivers/input/mouse/sermouse.c, which
>>>> is an example to program serial port in kernel space.
>>> Interesting. I wonder if that would have been a better choice for
>>> the Gigaset M101 driver. It seems even to have a probe mechanism
>>> so one could try to determine if the expected device is really
>>> connected to the port.
>>> Is there any documentation on this interface? I find the source a
>>> bit hard to understand, sparsely commented as it is.
>> how can I open ttyS1 with major=4 and minor=65?
>
> a) With "my" approach, ie. writing a line discipline, you open
> /dev/ttyS1 in a user space program and then push your line discipline
> onto it using ioctl(,TIOCSETD,).
>
> b) With the "serio" approach, if the probe mechanism is really what
> I think it is, you register your probe function and wait for it to
> be called for each active serial port, then do your thing to determine
> whether this is a/the port you want to use.
>
>> Does anybody have some code to read from it the first e.g. 2bytes?
>
> That's not how things work in the kernel. You don't "read the first
> <n> bytes" at will. You have to provide means to process whatever
> data happens to arrive on the serial port, as it arrives.
>
> a) With a line discipline, you provide a callback function
> ".receive_buf" which will be called by the serial driver if some
> data has been received, and has to process that data then and there.
> You might just stow it away in a buffer of course, provided you
> are sure to get around to processing it later.
>
> b) With the "serio" interface, it seems the ".interrupt" function
> serves the same purpose - though, as I said, I am not really
> competent on that topic.
>
> HTH
> T.
>
ok because I want to handle it in kernel space I will no take option a)

I will try it the way of b)

anyway thx.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.3 (MingW32) - GPGrelay v0.959

iD8DBQFGZm/aAAomYJ1taN8RAhS1AKC5xZVKXjZPAovXLmz2vuVr7JXssQCgqxs9
PUcqGC5sTzPtEzxuc5nkdes=
=qO4W
-----END PGP SIGNATURE-----

View attachment "lkwg82.vcf" of type "text/x-vcard" (132 bytes)