arch/powerpc/boot/gamecube-head.S

Source file repositories/reference/linux-study-clean/arch/powerpc/boot/gamecube-head.S

File Facts

System
Linux kernel
Corpus path
arch/powerpc/boot/gamecube-head.S
Extension
.S
Size
2232 bytes
Lines
107
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: arch/powerpc
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include "ppc_asm.h"

/*
 * The entry code does no assumptions regarding:
 * - if the data and instruction caches are enabled or not
 * - if the MMU is enabled or not
 *
 * We enable the caches if not already enabled, enable the MMU with an
 * identity mapping scheme and jump to the start code.
 */

	.text

	.globl _zimage_start
_zimage_start:

	/* turn the MMU off */
	mfmsr	9
	rlwinm	9, 9, 0, ~((1<<4)|(1<<5)) /* MSR_DR|MSR_IR */
	bcl	20, 31, 1f
1:
	mflr	8
	clrlwi	8, 8, 3		/* convert to a real address */
	addi	8, 8, _mmu_off - 1b
	mtsrr0	8
	mtsrr1	9
	rfi
_mmu_off:
	/* MMU disabled */

	/* setup BATs */
	isync
	li      8, 0
	mtspr	0x210, 8	/* IBAT0U */
	mtspr	0x212, 8	/* IBAT1U */
	mtspr	0x214, 8	/* IBAT2U */
	mtspr	0x216, 8	/* IBAT3U */
	mtspr	0x218, 8	/* DBAT0U */
	mtspr	0x21a, 8	/* DBAT1U */
	mtspr	0x21c, 8	/* DBAT2U */
	mtspr	0x21e, 8	/* DBAT3U */

	li	8, 0x01ff	/* first 16MiB */
	li	9, 0x0002	/* rw */
	mtspr	0x211, 9	/* IBAT0L */
	mtspr	0x210, 8	/* IBAT0U */
	mtspr	0x219, 9	/* DBAT0L */
	mtspr	0x218, 8	/* DBAT0U */

	lis	8, 0x0c00	/* I/O mem */
	ori	8, 8, 0x3ff	/* 32MiB */
	lis	9, 0x0c00
	ori	9, 9, 0x002a	/* uncached, guarded, rw */
	mtspr	0x21b, 9	/* DBAT1L */
	mtspr	0x21a, 8	/* DBAT1U */

	lis	8, 0x0100	/* next 8MiB */
	ori	8, 8, 0x00ff	/* 8MiB */
	lis	9, 0x0100
	ori	9, 9, 0x0002	/* rw */
	mtspr	0x215, 9	/* IBAT2L */
	mtspr	0x214, 8	/* IBAT2U */
	mtspr	0x21d, 9	/* DBAT2L */
	mtspr	0x21c, 8	/* DBAT2U */

	/* enable and invalidate the caches if not already enabled */
	mfspr	8, 0x3f0	/* HID0 */
	andi.	0, 8, (1<<15)		/* HID0_ICE */
	bne	1f
	ori	8, 8, (1<<15)|(1<<11)	/* HID0_ICE|HID0_ICFI*/

Annotation

Implementation Notes