[U-Boot-Users] mpc8260 reset procedure

[VanBaren, Gerald (AGRE)]

Also, debuggers do NOT like having the IMMR change by the software they are debugging.  They don't have any way of knowing that your software changed the IMMR, so they will be using the wrong IMMR, causing problems like you are seeing.

Tip: set the IMMR to where you want it (or can live with it) using the HRCW and DO NOT CHANGE IT in software.  Your phrase "as soon as the code starts to manage IMMR" is something that should not be said.  "Manageing" the IMMR causes problems for (a) debuggers, (b) software, (c) software resets/restarts, (d) code readability, ...

gvb


> -----Original Message-----
> From: u-boot-users-admin at lists.sourceforge.net
> [mailto:u-boot-users-admin at lists.sourceforge.net]On Behalf Of Ho Lee
> Sent: Thursday, June 10, 2004 2:47 AM
> To: u-boot-users at lists.sourceforge.net
> Cc: walter dicarlo
> Subject: Re: [U-Boot-Users] mpc8260 reset procedure
>
>
>
> Hi Walter,
>
> According to your HRCW configuration, IMMR is set to
> 0x0f000000 after reset.
> CFG_DEFAULT_IMMR must be the IMMR after system reset (in your
> configuration,
> 0x0f000000 not 0x00010000), and CFG_IMMR is the IMMR that you
> would like
> to use inside u-boot. Since you keep the IMMR defined by
> HRCW, you don't need to
> define the CFG_DEFAULT_IMMR. Just comment out the CFG_DEFAULT_IMMR
> definition, and I guess it will fix your problem.
>
> Sincerely,
> Ho
>
> ----- Original Message -----
> From: "walter dicarlo" <walter_dicarlo at yahoo.com>
> To: <u-boot-users at lists.sourceforge.net>
> Sent: Wednesday, June 09, 2004 7:58 AM
> Subject: [U-Boot-Users] mpc8260 reset procedure
>
>
> Hi all,
> I am new to embedded world and I am trying to port
> u-boot on a board based on the mpc8260.
> I hope I can bore you a little bit with a simple
> question.
> I use the Lauterbach Trace32 to program the 4Mb flash.
> I compile u-boot 1.0.2 using the following settings:
> TEXT_BASE = fff00000
> CFG_DEFAULT_IMMR = 00010000
> CFG_IMMR = 0f000000
> CFG_SDRAM_BASE = 00000000
> CFG_FLASH_BASE = ffc00000
> CFG_BR0_PRELIM = ffc01001
> CFG_OR0_PRELIM = ffc00856
> CFG_BR1_PRELIM = 00000041
> CFG_OR1_PRELIM = f8002b00
> HRCW = 08 c2 01 07
> Note that I use three Trace32 scripts to:
> - init the board
> - store the HRCW at the begin of the flash (FFC00000)
> - store the u-boot.bin at fff00000
>
> My problem is with the HRCW and the reset procedure.
> It is not clear how it works and what steps I should
> follow to setup everything.
>
> When I start debugging, the Program Counter starts
> correctly from fff00100,
> but as soon as the code starts to manage IMMR
> everything seems to not
> work. It is like the code expect the registers in one
> position but in reality
> it is in another location.
>
> I know it is basic knoledge about the mpc8260 but do
> you have any advices?
> Thanks
>
> Walter
>
>
>
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