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- /*
- * 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
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