Experimental Physics and
Industrial Control System

Emmanuel Mayssat <[email protected]> · Fri, 05 Oct 2007 09:32:00 -0700

On Fri, 2007-10-05 at 10:41 +0800, Jenny Chen wrote:
> Dear Mark,
> > A Linux driver from a vendor would typically be started once when
> Linux is booted.
>  Let me rephrase this, if what I understand is right. 
> Before doing anything, the card driver should be implemented or
> supported by the vender (xxx.ko) then should be installed once when the
> system startup. 
> . when system boot, the BIOS sees the PCI cards, it assigns the PCI card
> address. 

To find the pci address in linux, use 'lspci' as root
The PCI address is function of the hardware location (pci slot) in the
computer. So if you fiddle with the hardware that address will change.

> . insmod xxx.ko should be called once during system boot (this might not
> be correct, maybe just only once then don't have to be called
> anymore)???

Look at 'modprobe' instead of 'insmod'. Modprobe loads driver
dependencies, while insmod doesn't.
Look at /etc/modprobe.conf or /etc/modules.conf that is where the driver
configuration goes. Use 'modprobe' in /etc/rc.d/rc.local

In the modprobe/modules file, 
1/ You can alias the driver
2/ You attach/configure the driver to the card. How this is done is
driver specific, but probably in a 'post-install' configuration
directive (this also is function of your linux distribution.

In rc.local
1/ you load the driver

Once booted, use 'lsmod' to see if your driver is loaded

> . EPICS asyn driver call open/read/write/ioctl/close to access that
> card, maybe different port for different card is better
> My I right?

Write a simple C/C++  program to access the data from the shell.
Then once this program works (once you understand the linux driver
library calls), then you can port it to asyn.

Asyn is great. I use it all the time. 
But if you are new to EPICS (and not so familiar with linux), you are
hitting 3 learning curves at once.

1. linux drivers and specific of that driver 
2. epics
3. asyn

That probably will make your task a challenging one.
Approach them one by one, not all at once.

Can you tell us, what you are trying to do, and which hardware you
intend to use?

Good luck,

--
Emmanuel

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System