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 */