xref: /plan9/sys/src/9/ppc/lucu.h (revision 458db83292ea45506704800dedf36a95598fc2ec)
1 /*
2  * on return from this function we will be running in virtual mode.
3  * We set up the Block Address Translation (BAT) registers thus:
4  * 1) first 3 BATs are 256M blocks, starting from KZERO->0
5  * 2) remaining BAT maps last 256M directly
6  */
7 TEXT	mmuinit0(SB), $0
8 	/* reset all the tlbs */
9 	MOVW	$64, R3
10 	MOVW	R3, CTR
11 	MOVW	$0, R4
12 
13 tlbloop:
14 	TLBIE	R4
15 	SYNC
16 	ADD		$BIT(19), R4
17 	BDNZ	tlbloop
18 	TLBSYNC
19 
20 	/* BATs 0 and 1 cover memory from 0x00000000 to 0x20000000 */
21 
22 	/* KZERO -> 0, IBAT2 and DBAT2, 256 MB */
23 	MOVW	$(KZERO|(0x7ff<<2)|2), R3
24 	MOVW	$(PTEVALID|PTEWRITE), R4	/* PTEVALID => Cache coherency on */
25 	MOVW	R3, SPR(DBATU(2))
26 	MOVW	R4, SPR(DBATL(2))
27 	MOVW	R3, SPR(IBATU(2))
28 	MOVW	R4, SPR(IBATL(2))
29 
30 	/* enable MMU */
31 	MOVW	LR, R3
32 	OR		$KZERO, R3
33 	MOVW	R3, SPR(SRR0)	/* Stored PC for RFI instruction */
34 	MOVW	MSR, R4
35 	OR		$(MSR_IR|MSR_DR|MSR_RI|MSR_FP), R4
36 	MOVW	R4, SPR(SRR1)
37 	RFI		/* resume in kernel mode in caller */
38 
39 	RETURN
40