[ixp1200] Question about the Linux kernel and the FBI RDYBUS registers.

[Raghunandan, Makaram]

This and several other FBI registers are WRITE only - so you can write to
them but cannot read the value back.
The Programmer's Ref. Manual indicates them as WRITE only.

-----Original Message-----
From: Didier CONTIS [mailto:didier at ece.gatech.edu]
Sent: Friday, May 04, 2001 4:16 PM
To: IXP1200 at CS.Princeton.EDU
Subject: [ixp1200] Question about the Linux kernel and the FBI RDYBUS
registers.


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


Hi,

I am observing a weird behavior when trying to read / write 
some registers from the Linux kernel running on the StrongARM.

Basically, it seems I can write some registers like IREG without
any problem from the StrongARM. However it seems I cannot with 
RDYBUS_TEMPLATE_CTL. However both registers are described in the doc 
as being r/w accessible by the StrongARM.

Below is the output of my program.
I am using the following definition for RDYBUS_TEMPLATE_CTL
(IREG being already defined in the includes files):

#define MY_RDYBUS_TEMPLATE_CTL
IXP1200_REG(MICROENGINE_FBI_BASE+0x40180)

[root at thing1 Didier]$./set_rcv   
Initial value of RDYBUS_TEMPLATE_CTL Register: 0 
Initial value of IREG Register: 0 

Address of RDYBUS_TEMPLATE_CTL Register: f0640180 
Address of IREG Register: f06401e0 

New value of RDYBUS_TEMPLATE_CTL Register: 0 
New value of IREG Register: 80000000 

Thanks in advance for any help.

Regards, Didier.

-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 6.5.3 for non-commercial use <http://www.pgp.com>

iQA/AwUBOvMOAHqEbTtUcuwQEQIARACeIhs42jMRRCCpV/1n4zKktqZenyQAoKKp
1KiT9hDkijWgnLVYRmz1B/g4
=sb4r
-----END PGP SIGNATURE-----