| /* |
| * arch/ppc/platforms/gemini_prom.S |
| * |
| * Not really prom support code (yet), but sort of anti-prom code. The current |
| * bootloader does a number of things it shouldn't and doesn't do things that it |
| * should. The stuff in here is mainly a hodge-podge collection of setup code |
| * to get the board up and running. |
| * ---Dan |
| */ |
| |
| #include <linux/config.h> |
| #include <asm/reg.h> |
| #include <asm/page.h> |
| #include <platforms/gemini.h> |
| #include <asm/ppc_asm.h> |
| |
| /* |
| * On 750's the MMU is on when Linux is booted, so we need to clear out the |
| * bootloader's BAT settings, make sure we're in supervisor state (gotcha!), |
| * and turn off the MMU. |
| * |
| */ |
| |
| _GLOBAL(gemini_prom_init) |
| #ifdef CONFIG_SMP |
| /* Since the MMU's on, get stuff in rom space that we'll need */ |
| lis r4,GEMINI_CPUSTAT@h |
| ori r4,r4,GEMINI_CPUSTAT@l |
| lbz r5,0(r4) |
| andi. r5,r5,3 |
| mr r24,r5 /* cpu # used later on */ |
| #endif |
| mfmsr r4 |
| li r3,MSR_PR /* ensure supervisor! */ |
| ori r3,r3,MSR_IR|MSR_DR |
| andc r4,r4,r3 |
| mtmsr r4 |
| isync |
| #if 0 |
| /* zero out the bats now that the MMU is off */ |
| prom_no_mmu: |
| li r3,0 |
| mtspr SPRN_IBAT0U,r3 |
| mtspr SPRN_IBAT0L,r3 |
| mtspr SPRN_IBAT1U,r3 |
| mtspr SPRN_IBAT1L,r3 |
| mtspr SPRN_IBAT2U,r3 |
| mtspr SPRN_IBAT2L,r3 |
| mtspr SPRN_IBAT3U,r3 |
| mtspr SPRN_IBAT3L,r3 |
| |
| mtspr SPRN_DBAT0U,r3 |
| mtspr SPRN_DBAT0L,r3 |
| mtspr SPRN_DBAT1U,r3 |
| mtspr SPRN_DBAT1L,r3 |
| mtspr SPRN_DBAT2U,r3 |
| mtspr SPRN_DBAT2L,r3 |
| mtspr SPRN_DBAT3U,r3 |
| mtspr SPRN_DBAT3L,r3 |
| #endif |
| |
| /* the bootloader (as far as I'm currently aware) doesn't mess with page |
| tables, but since we're already here, might as well zap these, too */ |
| li r4,0 |
| mtspr SPRN_SDR1,r4 |
| |
| li r4,16 |
| mtctr r4 |
| li r3,0 |
| li r4,0 |
| 3: mtsrin r3,r4 |
| addi r3,r3,1 |
| bdnz 3b |
| |
| #ifdef CONFIG_SMP |
| /* The 750 book (and Mot/IBM support) says that this will "assist" snooping |
| when in SMP. Not sure yet whether this should stay or leave... */ |
| mfspr r4,SPRN_HID0 |
| ori r4,r4,HID0_ABE |
| mtspr SPRN_HID0,r4 |
| sync |
| #endif /* CONFIG_SMP */ |
| blr |
| |
| /* apparently, SMon doesn't pay attention to HID0[SRST]. Disable the MMU and |
| branch to 0xfff00100 */ |
| _GLOBAL(_gemini_reboot) |
| lis r5,GEMINI_BOOT_INIT@h |
| ori r5,r5,GEMINI_BOOT_INIT@l |
| li r6,MSR_IP |
| mtspr SPRN_SRR0,r5 |
| mtspr SPRN_SRR1,r6 |
| rfi |