Porting OpeniBoot

From The Apple Wiki
(Redirected from Porting Openiboot)

This page should act as temporary place holder for any technical information found regarding porting Openiboot to newer devices.

3GS

Reboot (WDT)

There is not a specific WDT device in 3GS device tree. The reboot sequence instead accesses several registers in PMGR.

LDR     R1, =0xBF10021C
LDR     R3, =0xBF100214
MOVS    R0, #0
MOVS    R2, #1
STR     R0, [R1]
STR     R2, [R3]
LDR     R2, =0xBF100210
MOV.W   R3, #0x80000000
STR     R3, [R2]
MOVS    R3, #4
STR     R3, [R1]
STR     R0, [R2]

MIU

The MIU setup is found in the miu_init() in the LLB image instead. The register that contains MIU setting is 0xBF100000 (PMGR base address). The bit mask is now 3 instead of 7 for most other devices before this. Assume setting for map to 0x0 is 1, otherwise 2.

ROM:84006F44                 CBZ     R0, loc_84006F4C
ROM:84006F46                 CMP     R0, #1
ROM:84006F48                 BNE     loc_84006F68
ROM:84006F4A                 B       loc_84006F5A
ROM:84006F4C loc_84006F4C                            
ROM:84006F4C                 LDR     R2, =0xBF100000
ROM:84006F4E                 LDR     R3, [R2]
ROM:84006F50                 BIC.W   R3, R3, #3
ROM:84006F54                 ORR.W   R3, R3, #1
ROM:84006F58                 B       loc_84006F66
ROM:84006F5A loc_84006F5A                            
ROM:84006F5A                 LDR     R2, =0xBF100000
ROM:84006F5C                 LDR     R3, [R2]
ROM:84006F5E                 BIC.W   R3, R3, #3
ROM:84006F62                 ORR.W   R3, R3, #2
ROM:84006F66
ROM:84006F66 loc_84006F66                            
ROM:84006F66                 STR     R3, [R2]
ROM:84006F68
ROM:84006F68 loc_84006F68                            
ROM:84006F68                 LDR     R3, =0xBF100000
ROM:84006F6A                 LDR     R3, [R3]
ROM:84006F6C                 BX      LR