[U-Boot-Users] uboot newbie - tqm823 and memory conf question
tmaenner at aehr.com
Mon Feb 17 20:57:34 CET 2003
On Sun, 16 Feb 2003, Wolfgang Denk wrote:
> In message <3E4D97E5.4030708 at aehr.com> you wrote:
> > I have TQM823L-50 modules, which have a 26bit address / 32 bit I/O
> > external bus and I want to hook up external programmable logic, which
> > If I understand the MPC823 book correctly there already a "canned"
> > memory engine available to "talk" to an SRAM.
> > - To which CS is that hooked up to?
> That's completely your own choice.
> Well, not completely. The TQM8xxL modules use:
> CS0 / CS1 for the 2 flash banks
> CS2 for SDRAM
> CS3 for the CAN controllers (if fit)
> So depending if you have CAN on your modules or not you can chose
> form CS4...CS7 or from CS3...CS7.
Well then, how does the CPU "know" about that area?
- Is the Address area on that bus the actual physical range the CPU sees?
- Or, does it get mapped into the CPUs physical space via configuration?
- How does the CPU know, that it is SRAM or something else?
> > - What needs to be done to the boot-loader - ppcboot|u-boot?
> Strictly speaking, nothing. You can set up the memroy controller for
> this CS whenever you need it, i. e. for example in the Linux
> deriver's init routine. However, if you want to access the memory
> under U-Boot, you should at least add appropriate definitions for
> CFG_BR?_PRELIM and CFG_OR?_PRELIM to your board's config file.
OK, I need to setup the mem controller.
(I don't need access during "boot-loader" time)
I will search in the source there.
Is that then still possible to change the mem controller setup when the
kernel is already coming up?? I hope so!
> > I would really appreciate some help there, since I am just supposed to
> > setup the board for our HW guys.
> Good luck.
Yeah, I need that :-)
Thanks for your help
> 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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