/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright 2010 IBM Corp, Benjamin Herrenschmidt <benh@kernel.crashing.org>
 *
 * Generic idle routine for 64 bits e500 processors
 */

#include <linux/threads.h>
#include <asm/reg.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ppc-opcode.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
#include <asm/epapr_hcalls.h>
#include <asm/hw_irq.h>

/* 64-bit version only for now */
.macro BOOK3E_IDLE name loop
_GLOBAL(\name)
        /* Save LR for later */
        mflr    r0
        std     r0,16(r1)

        /* Hard disable interrupts */
        wrteei  0

        /* Now check if an interrupt came in while we were soft disabled
         * since we may otherwise lose it (doorbells etc...).
         */
        lbz     r3,PACAIRQHAPPENED(r13)
        cmpwi   cr0,r3,0
        bne     2f

        /* Now we are going to mark ourselves as soft and hard enabled in
         * order to be able to take interrupts while asleep. We inform lockdep
         * of that. We don't actually turn interrupts on just yet tho.
         */
#ifdef CONFIG_TRACE_IRQFLAGS
        stdu    r1,-128(r1)
        bl      trace_hardirqs_on
        addi    r1,r1,128
#endif
        li      r0,IRQS_ENABLED
        stb     r0,PACAIRQSOFTMASK(r13)
        
        /* Interrupts will make use return to LR, so get something we want
         * in there
         */
        bl      1f

        /* And return (interrupts are on) */
        ld      r0,16(r1)
        mtlr    r0
        blr

1:      /* Let's set the _TLF_NAPPING flag so interrupts make us return
         * to the right spot
        */
        ld      r11, PACACURRENT(r13)
        ld      r10,TI_LOCAL_FLAGS(r11)
        ori     r10,r10,_TLF_NAPPING
        std     r10,TI_LOCAL_FLAGS(r11)

        /* We can now re-enable hard interrupts and go to sleep */
        wrteei  1
        \loop

2:
        lbz     r10,PACAIRQHAPPENED(r13)
        ori     r10,r10,PACA_IRQ_HARD_DIS
        stb     r10,PACAIRQHAPPENED(r13)
        blr
.endm

.macro BOOK3E_IDLE_LOOP
1:
        PPC_WAIT_v203
        b       1b
.endm

/* epapr_ev_idle_start below is patched with the proper hcall
   opcodes during kernel initialization */
.macro EPAPR_EV_IDLE_LOOP
idle_loop:
        LOAD_REG_IMMEDIATE(r11, EV_HCALL_TOKEN(EV_IDLE))

.global epapr_ev_idle_start
epapr_ev_idle_start:
        li      r3, -1
        nop
        nop
        nop
        b       idle_loop
.endm

BOOK3E_IDLE epapr_ev_idle EPAPR_EV_IDLE_LOOP

BOOK3E_IDLE e500_idle BOOK3E_IDLE_LOOP