[U-Boot-Users] [ARM-AT91RM9200] Should D-Cache be OFF for booting Linux-ARM?

[Anders Larsen]

"Paugam Luc" <luc.paugam at thomson.net> schreibt:
>My U-Boot dev. Env: eldk-arm-linux-x86 v3.1.1, ARCH=arm, CPU=AT91RM9200,
>BOARD="custom"
>
>I would like to know if D-Cache has to be set OFF or ON in order to boot
>Linux?

OFF (see http://www.arm.linux.org/developer/booting.php)
>
>Because at first I enable the D-Cache into start.S, but the Linux kernel
>source codes (arch/arm/kernel/head-armv.S) require that D-Cache must be
>OFF by the boot loader.

Then you already knew the answer to your question.
>
>What do U-Boot developers while booting Linux-arm from U-Boot?

Follow the guidelines from rmk, of course.
>
>Here is my cp15 initialization, coded into start.S

Err, why don't you use the already present cpu/arm920t/start.S
and cpu/arm920t/at91rm9200/lowlevel_init.S ?

>    /* set bits 31:30 (iA, nF) Asynchronous Clocking mode */
>    orr     r0, r0, #0xC0000000

Don't touch the clocking mode until /after/ you have set up
the PLLs and given them time to stabilize!

Cheers
 Anders