1/* SPDX-License-Identifier: GPL-2.0-or-later */
 2/*
 3 *  This file contains the power_save function for 970-family CPUs.
 4 */
 5
 6#include <linux/threads.h>
 7#include <asm/processor.h>
 8#include <asm/page.h>
 9#include <asm/cputable.h>
10#include <asm/thread_info.h>
11#include <asm/ppc_asm.h>
12#include <asm/asm-offsets.h>
13#include <asm/irqflags.h>
14#include <asm/hw_irq.h>
15#include <asm/feature-fixups.h>
16
17#undef DEBUG
18
19	.text
20
21_GLOBAL(power4_idle)
22BEGIN_FTR_SECTION
23	blr
24END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP)
25	/* Now check if user or arch enabled NAP mode */
26	LOAD_REG_ADDRBASE(r3,powersave_nap)
27	lwz	r4,ADDROFF(powersave_nap)(r3)
28	cmpwi	0,r4,0
29	beqlr
30
31	/* This sequence is similar to prep_irq_for_idle() */
32
33	/* Hard disable interrupts */
34	mfmsr	r7
35	rldicl	r0,r7,48,1
36	rotldi	r0,r0,16
37	mtmsrd	r0,1
38
39	/* Check if something happened while soft-disabled */
40	lbz	r0,PACAIRQHAPPENED(r13)
41	cmpwi	cr0,r0,0
42	bne-	2f
43
44	/*
45	 * Soft-enable interrupts. This will make power4_fixup_nap return
46	 * to our caller with interrupts enabled (soft and hard). The caller
47	 * can cope with either interrupts disabled or enabled upon return.
48	 */
49#ifdef CONFIG_TRACE_IRQFLAGS
50	/* Tell the tracer interrupts are on, because idle responds to them. */
51	mflr	r0
52	std	r0,16(r1)
53	stdu    r1,-128(r1)
54	bl	trace_hardirqs_on
55	addi    r1,r1,128
56	ld	r0,16(r1)
57	mtlr	r0
58	mfmsr	r7
59#endif /* CONFIG_TRACE_IRQFLAGS */
60
61	li	r0,IRQS_ENABLED
62	stb	r0,PACAIRQSOFTMASK(r13)	/* we'll hard-enable shortly */
63BEGIN_FTR_SECTION
64	DSSALL
65	sync
66END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
67	ld	r9, PACA_THREAD_INFO(r13)
68	ld	r8,TI_LOCAL_FLAGS(r9)	/* set napping bit */
69	ori	r8,r8,_TLF_NAPPING	/* so when we take an exception */
70	std	r8,TI_LOCAL_FLAGS(r9)	/* it will return to our caller */
71	ori	r7,r7,MSR_EE
72	oris	r7,r7,MSR_POW@h
731:	sync
74	isync
75	mtmsrd	r7
76	isync
77	b	1b
78
792:	/* Return if an interrupt had happened while soft disabled */
80	/* Set the HARD_DIS flag because interrupts are now hard disabled */
81	ori	r0,r0,PACA_IRQ_HARD_DIS
82	stb	r0,PACAIRQHAPPENED(r13)
83	blr