cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pm.c (3131B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * loongson-specific suspend support
      4 *
      5 *  Copyright (C) 2009 Lemote Inc.
      6 *  Author: Wu Zhangjin <wuzhangjin@gmail.com>
      7 */
      8#include <linux/suspend.h>
      9#include <linux/interrupt.h>
     10#include <linux/pm.h>
     11
     12#include <asm/i8259.h>
     13#include <asm/mipsregs.h>
     14
     15#include <loongson.h>
     16
     17static unsigned int __maybe_unused cached_master_mask;	/* i8259A */
     18static unsigned int __maybe_unused cached_slave_mask;
     19static unsigned int __maybe_unused cached_bonito_irq_mask; /* bonito */
     20
     21void arch_suspend_disable_irqs(void)
     22{
     23	/* disable all mips events */
     24	local_irq_disable();
     25
     26#ifdef CONFIG_I8259
     27	/* disable all events of i8259A */
     28	cached_slave_mask = inb(PIC_SLAVE_IMR);
     29	cached_master_mask = inb(PIC_MASTER_IMR);
     30
     31	outb(0xff, PIC_SLAVE_IMR);
     32	inb(PIC_SLAVE_IMR);
     33	outb(0xff, PIC_MASTER_IMR);
     34	inb(PIC_MASTER_IMR);
     35#endif
     36	/* disable all events of bonito */
     37	cached_bonito_irq_mask = LOONGSON_INTEN;
     38	LOONGSON_INTENCLR = 0xffff;
     39	(void)LOONGSON_INTENCLR;
     40}
     41
     42void arch_suspend_enable_irqs(void)
     43{
     44	/* enable all mips events */
     45	local_irq_enable();
     46#ifdef CONFIG_I8259
     47	/* only enable the cached events of i8259A */
     48	outb(cached_slave_mask, PIC_SLAVE_IMR);
     49	outb(cached_master_mask, PIC_MASTER_IMR);
     50#endif
     51	/* enable all cached events of bonito */
     52	LOONGSON_INTENSET = cached_bonito_irq_mask;
     53	(void)LOONGSON_INTENSET;
     54}
     55
     56/*
     57 * Setup the board-specific events for waking up loongson from wait mode
     58 */
     59void __weak setup_wakeup_events(void)
     60{
     61}
     62
     63/*
     64 * Check wakeup events
     65 */
     66int __weak wakeup_loongson(void)
     67{
     68	return 1;
     69}
     70
     71/*
     72 * If the events are really what we want to wakeup the CPU, wake it up
     73 * otherwise put the CPU asleep again.
     74 */
     75static void wait_for_wakeup_events(void)
     76{
     77	while (!wakeup_loongson())
     78		writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);
     79}
     80
     81/*
     82 * Stop all perf counters
     83 *
     84 * $24 is the control register of Loongson perf counter
     85 */
     86static inline void stop_perf_counters(void)
     87{
     88	__write_64bit_c0_register($24, 0, 0);
     89}
     90
     91
     92static void loongson_suspend_enter(void)
     93{
     94	unsigned int cached_cpu_freq;
     95
     96	/* setup wakeup events via enabling the IRQs */
     97	setup_wakeup_events();
     98
     99	stop_perf_counters();
    100
    101	cached_cpu_freq = readl(LOONGSON_CHIPCFG);
    102
    103	/* Put CPU into wait mode */
    104	writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);
    105
    106	/* wait for the given events to wakeup cpu from wait mode */
    107	wait_for_wakeup_events();
    108
    109	writel(cached_cpu_freq, LOONGSON_CHIPCFG);
    110
    111	mmiowb();
    112}
    113
    114void __weak mach_suspend(void)
    115{
    116}
    117
    118void __weak mach_resume(void)
    119{
    120}
    121
    122static int loongson_pm_enter(suspend_state_t state)
    123{
    124	mach_suspend();
    125
    126	/* processor specific suspend */
    127	loongson_suspend_enter();
    128
    129	mach_resume();
    130
    131	return 0;
    132}
    133
    134static int loongson_pm_valid_state(suspend_state_t state)
    135{
    136	switch (state) {
    137	case PM_SUSPEND_ON:
    138	case PM_SUSPEND_STANDBY:
    139	case PM_SUSPEND_MEM:
    140		return 1;
    141
    142	default:
    143		return 0;
    144	}
    145}
    146
    147static const struct platform_suspend_ops loongson_pm_ops = {
    148	.valid	= loongson_pm_valid_state,
    149	.enter	= loongson_pm_enter,
    150};
    151
    152static int __init loongson_pm_init(void)
    153{
    154	suspend_set_ops(&loongson_pm_ops);
    155
    156	return 0;
    157}
    158arch_initcall(loongson_pm_init);