1/*
2 * Copyright 2010 IBM Corp, Benjamin Herrenschmidt <benh@kernel.crashing.org>
3 *
4 * Generic idle routine for Book3E processors
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/threads.h>
13#include <asm/reg.h>
14#include <asm/ppc_asm.h>
15#include <asm/asm-offsets.h>
16#include <asm/ppc-opcode.h>
17#include <asm/processor.h>
18#include <asm/thread_info.h>
19#include <asm/epapr_hcalls.h>
20
21/* 64-bit version only for now */
22#ifdef CONFIG_PPC64
23
24.macro BOOK3E_IDLE name loop
25_GLOBAL(\name)
26	/* Save LR for later */
27	mflr	r0
28	std	r0,16(r1)
29
30	/* Hard disable interrupts */
31	wrteei	0
32
33	/* Now check if an interrupt came in while we were soft disabled
34	 * since we may otherwise lose it (doorbells etc...).
35	 */
36	lbz	r3,PACAIRQHAPPENED(r13)
37	cmpwi	cr0,r3,0
38	bnelr
39
40	/* Now we are going to mark ourselves as soft and hard enabled in
41	 * order to be able to take interrupts while asleep. We inform lockdep
42	 * of that. We don't actually turn interrupts on just yet tho.
43	 */
44#ifdef CONFIG_TRACE_IRQFLAGS
45	stdu    r1,-128(r1)
46	bl	trace_hardirqs_on
47	addi    r1,r1,128
48#endif
49	li	r0,1
50	stb	r0,PACASOFTIRQEN(r13)
51
52	/* Interrupts will make use return to LR, so get something we want
53	 * in there
54	 */
55	bl	1f
56
57	/* And return (interrupts are on) */
58	ld	r0,16(r1)
59	mtlr	r0
60	blr
61
621:	/* Let's set the _TLF_NAPPING flag so interrupts make us return
63	 * to the right spot
64	*/
65	CURRENT_THREAD_INFO(r11, r1)
66	ld	r10,TI_LOCAL_FLAGS(r11)
67	ori	r10,r10,_TLF_NAPPING
68	std	r10,TI_LOCAL_FLAGS(r11)
69
70	/* We can now re-enable hard interrupts and go to sleep */
71	wrteei	1
72	\loop
73
74.endm
75
76.macro BOOK3E_IDLE_LOOP
771:
78	PPC_WAIT(0)
79	b	1b
80.endm
81
82/* epapr_ev_idle_start below is patched with the proper hcall
83   opcodes during kernel initialization */
84.macro EPAPR_EV_IDLE_LOOP
85idle_loop:
86	LOAD_REG_IMMEDIATE(r11, EV_HCALL_TOKEN(EV_IDLE))
87
88.global epapr_ev_idle_start
89epapr_ev_idle_start:
90	li      r3, -1
91	nop
92	nop
93	nop
94	b       idle_loop
95.endm
96
97BOOK3E_IDLE epapr_ev_idle EPAPR_EV_IDLE_LOOP
98
99BOOK3E_IDLE book3e_idle BOOK3E_IDLE_LOOP
100
101#endif /* CONFIG_PPC64 */
102