sysmo-bts
/
barebox
9
0
Fork 0
Code Releases Activity

Improve the ARM architecture documentation part 

Signed-off-by: Juergen Beisert <j.beisert@pengutronix.de>
This commit is contained in:
Juergen Beisert 2009-07-31 13:10:49 +02:00
parent 4e0c96946c
commit d4babacc26
1 changed files with 23 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
arch/arm/mach-arm.dox
View File

@ -6,7 +6,7 @@
FIXME
@par What's happens when the reset signal is gone
@section mach_arm_reset What's happens when the reset signal is gone
@note Code running immediately after reset runs at an address it is not linked
to: "runtime address != link address". You should only use branches and
@ -22,29 +22,44 @@ After handling some MMU related things \<board_init_lowlevel\> can be called (if
not disabled). This is a board specific function for SDRAM setup for example.
As its board specific, your can do whatever you need to bring your board up.
In the case the boot happens from NAND flash memory, further steps are required.
Most of the known processor devices are reading the first few blocks from the
NAND flash memory into some kind of internal SRAM. This small part must be able
to initialize the SDRAM controller and to read the remaining rest of the
U-Boot-v2 binary from the NAND flash memory prior returning from \<board_init_lowlevel\>.
When \<board_init_lowlevel\> returns it will be assumed there is now a working
RAM that can be used for all further steps.
Next step is relocation of U-Boot itself. It gets copied to RAM and the last
assembler instruction is a jump into \<start_uboot\>. This target address is
the first C instruction in U-Boot. At this point of time:\n
Next step is relocation of U-Boot itself (if not already done). It gets copied
to RAM and the last assembler instruction is a jump into start_uboot(). This
target address is the first C instruction in U-Boot. At this point of time:\n
"runtime address == link address".
@par Architectures using ARM processors
For details on specific architectures:
- @subpage dev_omap_arch
@section mach_arm_files List of changes
Lets call the new MACH new_cpu.
- create a new subdirectory in /arch/arm/new_cpu
- create a new subdirectory in /include/asm-arm/new_cpu
- add CPU specific definitions into /include/asm-arm/new_cpu/
- add /arch/arm/new_cpu/Kconfig
- add /arch/arm/new_cpu/Makfile
- add other CPU specific code into /arch/arm/new_cpu/
- modify /arch/arm/Kconfig
- modify /arch/arm/Makfile
@section mach_arm_architecures Architectures using ARM processors
For details on specific architectures:
@subsection mach_arm_omap_info OMAP CPUs
@li @subpage dev_omap_arch
@subsection mach_arm_s3c24xx_info S3C24XX CPUs
@li @subpage dev_s3c24xx_arch
TODO add more details
*/