Subject: RE: PowerPC + SMP

From: "Stuart Yoder" <[email-masked]>
Date: Tue, 26 Apr 2005 14:07:36 -0500

We've run into a few issues with U-boot, but they are not unsolveable--

-it doesn't provide an alternate execution path for the 2nd CPU when it
is started by the kernel
-U-boot needs to detect which CPU is executing
-U-boot on the 2nd CPU should not execute any platform/board specific
setup code-- this is stuff you only want to do once
-U-boot on the 2nd CPU cannot relocate itself to SDRAM because Linux is
already running there and assumes it owns all of memory
-it needs some way of getting to the Linux kernel entry point for
secondary CPUs
-it also appears that it should set up HID1 (other stuff??) for SMP
systems

Stuart

> -----Original Message-----
> From: Wolfgang Denk [mailto:[email-masked]] 
> Sent: Tuesday, April 26, 2005 12:35 PM
> To: Stuart Yoder
> Cc: 'linuxppc-dev list'
> Subject: Re: PowerPC + SMP 
> 
> 
> In message <[email-masked]> you wrote:
> > 
> > I am using U-boot on my SMP system and U-boot is not SMP aware.  Do 
> > you
> 
> Strictly speaking this statement is wrong.
> 
> So far I am not aware of a port of U-Boot to a SMP system.  
> If  there was  such  a  port, and if it was properly done, 
> then U-Boot probably _were_ SMP aware.
> 
> Best regards,
> 
> Wolfgang Denk
> 
> -- 
> Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: 
> [email-masked] Every program has at least one bug and can be 
> shortened by  at  least one  instruction  --  from  which,  
> by induction, one can deduce that every program can be 
> reduced to one instruction which doesn't work.
> 
> 
>