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/*
* arch/ppc/kernel/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 "ppc_asm.tmpl"
#include "ppc_defs.h"
#include <linux/config.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/gemini.h>
#define HID0_ABE (1<<3)
/*
* 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(prom_init)
_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
#if 0
/* zero out the bats now that the MMU is off */
prom_no_mmu:
li r3,0
mtspr IBAT0U,r3
mtspr IBAT0L,r3
mtspr IBAT1U,r3
mtspr IBAT1L,r3
mtspr IBAT2U,r3
mtspr IBAT2L,r3
mtspr IBAT3U,r3
mtspr IBAT3L,r3
mtspr DBAT0U,r3
mtspr DBAT0L,r3
mtspr DBAT1U,r3
mtspr DBAT1L,r3
mtspr DBAT2U,r3
mtspr DBAT2L,r3
mtspr DBAT3U,r3
mtspr 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 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,HID0
ori r4,r4,HID0_ABE
mtspr 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 SRR0,r5
mtspr SRR1,r6
rfi
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