[U-Boot-Users] Auto-detected parameters CpuFreq and granularity no longer autodetected.

Wolfgang Denk wd at denx.de
Thu Aug 28 14:01:50 CEST 2003

Dear Seb,

in message <1062067871.3292.119.camel at xerxes.hypercube> you wrote:
> 	Does u-boot pass anything to the linux environment regarding
>  	CpuFreq, and granularity, both of which are symbols recognized by
>  	rtai?

The boot loader passes the CPU clock to the Linux kernel; it is  part
of  the  bd_info  structure which is passed in register r3 when Linux
gets started.

> What have I done? Well, I re-loaded the bootloader, u-boot, onto the
> targets and I don't think I have changed anything else.

Which version of  U-Boot?  And  did  you  restore  the  _exact_  same
contents of the the U-Boot environment variables?

> Linux version 2.4.4-rthal5 (seb at mst26) (gcc version 2.95.4 20010319
> (prerelease/franzo/20011204)) #8 Wed Jun 25 16:28:38 BST 2003
> I2C uCode patch installed
> On node 0 totalpages: 4096
> zone(0): 4096 pages.
> zone(1): 0 pages.
> zone(2): 0 pages.
> Kernel command line: root=/dev/ram rw
> ip=
> panic=1
> Decrementer Frequency: 3125000
> Calibrating delay loop... 49.86 BogoMIPS

Both the output for the decrementer freq and  the  bogomips  indicate
that  U-Boot correctly passed a CPU clock rate of 50 MHz to the Linux

> Freeing unused kernel memory: 56k init
> init started:  BusyBox v0.60.2 (2003.07.07-11:04+0000) multi-call

Everything looks perfectly fine to me until here.

> Warning: /lib/modules/rtai/rtai.o symbol for parameter CpuFreq not found
> Warning: /lib/modules/rtai/rtai_sched_up.o symbol for parameter
> granularity not
> found

[BTW: can you please turn off automatic line wrap when  posting  such
messages? It makes it really difficult to parse the output.]

> The question is: where do CpuFreq and granularity come from? 

These  are  module  parameters  to   the   rtai.o   (CpuFreq)   resp.
rtai_sched_up.o (granularity) parameters.

> A search of the u-boot tree for CpuFreq gives nothing. A search in linux
> threw up no CpuFreq symbol, either, but rtai mentions it in rtai.c and
> rtai_arch.c. It seems that this is a parameter which linux normally
> autodetects and one which can be passed on the command line when
> insmodding rtai modules. The same for granularity, as part of the rtai
> dynamic memory allocation scheme.

Right, and both of them have appropriate default values.

> Can anyone help me to fix this? I'm really stuck...

Which version of insmod are you using? The one builtin with  busybox?
BusyBox  v0.60.2  might  have  some  problems  here  ... Try out what
happens when you disable the modutils option in busybox, and use  the
binaries from the ELDK.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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