a question about mpc8xx linux

a question about mpc8xx linux

[poorbeyond]

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my cpu is MPC860, use u-boot-1.1.4, linux-2.6.20.14

i use the "tftp 300000 uImage" command download kernel image,

then use the "bootm 300000" command boot the image.


i found the bootm cmd entered the /arch/ppc/kernel/head_8xx.s, stop at the instruction "rfi".
is it right? after the instruction, where does the code go normally ? what should i do now?

thanks

 .globl __start
__start:
 mr r31,r3   /* save parameters */
 mr r30,r4
 mr r29,r5
 mr r28,r6
 mr r27,r7

 /* We have to turn on the MMU right away so we get cache modes
  * set correctly.
  */
 bl initial_mmu

/* We now have the lower 8 Meg mapped into TLB entries, and the caches
 * ready to work.
 */

turn_on_mmu:
 mfmsr r0
 ori r0,r0,MSR_DR|MSR_IR
 mtspr SPRN_SRR1,r0
 lis r0,start_here@h
 ori r0,r0,start_here@l
 mtspr SPRN_SRR0,r0
 SYNC
 rfi    /* enables MMU */







poorbeyond
2007-07-27

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Re: a question about mpc8xx linux

[Scott Wood]

poorbeyond wrote:
> my cpu is MPC860, use u-boot-1.1.4, linux-2.6.20.14
> 
> i use the "tftp 300000 uImage" command download kernel image,
> 
> then use the "bootm 300000" command boot the image.

You'll need either a device-tree-aware u-boot or 8xx cuImage support; 
you can get the latter from the patchset I posted recently.

> i found the bootm cmd entered the /arch/ppc/kernel/head_8xx.s, stop at the instruction "rfi".
> is it right? after the instruction, where does the code go normally ? what should i do now?

The rfi transfers control to start_here:

-Scott

Re: a question about mpc8xx linux

[Scott Wood]

Scott Wood wrote:
> poorbeyond wrote:
> 
>>my cpu is MPC860, use u-boot-1.1.4, linux-2.6.20.14
>>
>>i use the "tftp 300000 uImage" command download kernel image,
>>
>>then use the "bootm 300000" command boot the image.
> 
> 
> You'll need either a device-tree-aware u-boot or 8xx cuImage support; 
> you can get the latter from the patchset I posted recently.

Sorry, I missed that you're using arch/ppc rather than arch/powerpc.

arch/ppc doesn't require a device tree, though it would be good to 
switch to arch/powerpc once my 8xx fixes go in -- arch/ppc is deprecated.

-Scott

Re: a question about mpc8xx linux

[Barisa kisku]

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how do you know execution stop at "rfi" instruction.i think it seems it stop at "rfi"  instruction when debugging through debugger, but it does n't . you check it by putting break point in the later functions e.g start_here, machine_init etc.
       
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