I have no screen that's why I have to use UART. I followed the CPM model in head_32.S :
#ifdef CONFIG_PPC_EARLY_DEBUG_CPM
setup_cpm_bat:
    lis    r8, 0xf000
    ori    r8, r8,    0x002a
    mtspr    SPRN_DBAT1L, r8

    lis    r11, 0xf000
    ori    r11, r11, (BL_1M << 2) | 2
    mtspr    SPRN_DBAT1U, r11

    blr
#endif

With this code  I can use udbg.

According to you, what is the best way ?

2008/8/18, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
On Mon, 2008-08-18 at 16:17 +0200, Sébastien Chrétien wrote:
> The mpc7448hpc2 uses a tsi108-bridge. My board uses an IP on a FPGA..
> I read the code of mpc7448_hpc2.c.
> It uses a ioremap in order to iniatilize the tsi108 registers. But I
> have already initialized MMU with my registers in HEAD_32.S. Do I need
> to use ioremap in setup_arch() ?


Why did you hack head_32.S ? You shouldn't do that... This is common
code, not platform code.

Ben.

>
>
>
> 2008/8/18, Michael Ellerman <michael@ellerman.id.au>:
>         On Mon, 2008-08-18 at 13:35 +0200, Sébastien Chrétien wrote:
>         > Can somebody explain me the aim of the
>         function  "setup_arch" in the
>         > machine_call structure ?
>
>
>         Is this MPC7448 anything like an mpc7448hpc2 ?
>
>         If so maybe you should start by looking at the code for it in:
>
>         arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
>
>         Even if it's not related, that will give you some idea of what
>         the
>         callbacks are for.
>
>         cheers
>
>         --
>         Michael Ellerman
>         OzLabs, IBM Australia Development Lab
>
>         wwweb: http://michael.ellerman.id.au
>         phone: +61 2 6212 1183 (tie line 70 21183)
>
>         We do not inherit the earth from our ancestors,
>         we borrow it from our children. - S.M.A.R.T Person
>
>