powerPC linux boot sequence

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Any can help me to find the boot sequence of powerPC 83xx of linux
kernel after the bootloader transfer control to kernel..

Please please help me....

thanks,
Nabendu

Re: powerPC linux boot sequence
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Look in this area:
arch/powerpc/platforms/83xx

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Michael N. Moran           (h) 770 516 7918
5009 Old Field Ct.         (c) 678 521 5460
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Re: powerPC linux boot sequence
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yes I had gone through that directory, but could not find entry point
from which bootloder ( u-boot) gives transfer to linux Image.

My board is freescale 834x MDS.


Regards,
Nabendu

Re: powerPC linux boot sequence
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The details may vary, but a Google for
"Linux PPC Boot Sequence" gave me this
link for the PPC 8xx, which will likely
be similar depending on your needs.

<http://gicl.cs.drexel.edu/people/sevy/linux/PPC_Linux_boot_sequence.html


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Michael N. Moran           (h) 770 516 7918
5009 Old Field Ct.         (c) 678 521 5460
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Re: powerPC linux boot sequence
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I hadn't found any head.S assembly file. [:( ]in boot dir of arch/
powerpc/boot) or like ps3-head.s for  powerpc 83xx.

also it is not like ppc/boot/ dir & file structure.


Regards,
Nabendu

Re: powerPC linux boot sequence
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Searching arch/arm I found:

arch/arm/kernel/head.S
arch/arm/boot/compressed/head.S

The upper-case '.S' extension on assembly source files is
used to identify assembly source files that use the C
processor before being assembled with 'as'.

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Michael N. Moran           (h) 770 516 7918
5009 Old Field Ct.         (c) 678 521 5460
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Re: powerPC linux boot sequence
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yes I had gone through that directory, but could not find entry point
like head.s in x86
from which bootloder ( u-boot) gives transfer to linux Image.

My board is freescale 834x MDS.

Regards,
Nabendu

Re: powerPC linux boot sequence
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mkimage is run as part of the kernel build process, and creates the imag
header that uboot (or whatever boot program you're using) uses to locat
the linux entry point.  mkimage compresses the kernel and builds the imag
header record.  e.g. the load address is 0x0 and the entry point for th
kernel is 0x100000:

mkimage –n "Kernel 2.4.18" –A arm –O linux –T kernel –C gzi
–a 0 –e 100000 -d Image.gz:initrd.gz multi-2.4.18.img

the image record header format is:
/*
 * Legacy format image header,
 * all data in network byte order (aka natural aka bigendian).
 */
typedef struct image_header {
    uint32_t    ih_magic;    /* Image Header Magic Number    */
    uint32_t    ih_hcrc;    /* Image Header CRC Checksum    */
    uint32_t    ih_time;    /* Image Creation Timestamp    */
    uint32_t    ih_size;    /* Image Data Size        */
    uint32_t    ih_load;    /* Data     Load  Address        */
    uint32_t    ih_ep;        /* Entry Point Address        */
    uint32_t    ih_dcrc;    /* Image Data CRC Checksum    */
    uint8_t        ih_os;        /* Operating System        */
    uint8_t        ih_arch;    /* CPU architecture        */
    uint8_t        ih_type;    /* Image Type            */
    uint8_t        ih_comp;    /* Compression Type        */
    uint8_t        ih_name[IH_NMLEN];    /* Image Name        */
} image_header_t;

So the key is to find where in your build environment the section tha
contains the Linux entry code is located to the ih_ep location.  Search fo
"__attribute__((section" in your kernel tree, and that should lead you t
the entry point.  You can also check your linker ld script to see whic
section is located at the ih_ep, and then work back from there to find th
named section in the source.

Jeff Ramsey
www.e2atechnology.com



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