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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bcm2835_timer.c (3212B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * Copyright 2012 Simon Arlott
      4 */
      5
      6#include <linux/bitops.h>
      7#include <linux/clockchips.h>
      8#include <linux/clocksource.h>
      9#include <linux/interrupt.h>
     10#include <linux/irqreturn.h>
     11#include <linux/kernel.h>
     12#include <linux/module.h>
     13#include <linux/of_address.h>
     14#include <linux/of_irq.h>
     15#include <linux/of_platform.h>
     16#include <linux/slab.h>
     17#include <linux/string.h>
     18#include <linux/sched_clock.h>
     19
     20#include <asm/irq.h>
     21
     22#define REG_CONTROL	0x00
     23#define REG_COUNTER_LO	0x04
     24#define REG_COUNTER_HI	0x08
     25#define REG_COMPARE(n)	(0x0c + (n) * 4)
     26#define MAX_TIMER	3
     27#define DEFAULT_TIMER	3
     28
     29struct bcm2835_timer {
     30	void __iomem *control;
     31	void __iomem *compare;
     32	int match_mask;
     33	struct clock_event_device evt;
     34};
     35
     36static void __iomem *system_clock __read_mostly;
     37
     38static u64 notrace bcm2835_sched_read(void)
     39{
     40	return readl_relaxed(system_clock);
     41}
     42
     43static int bcm2835_time_set_next_event(unsigned long event,
     44	struct clock_event_device *evt_dev)
     45{
     46	struct bcm2835_timer *timer = container_of(evt_dev,
     47		struct bcm2835_timer, evt);
     48	writel_relaxed(readl_relaxed(system_clock) + event,
     49		timer->compare);
     50	return 0;
     51}
     52
     53static irqreturn_t bcm2835_time_interrupt(int irq, void *dev_id)
     54{
     55	struct bcm2835_timer *timer = dev_id;
     56	void (*event_handler)(struct clock_event_device *);
     57	if (readl_relaxed(timer->control) & timer->match_mask) {
     58		writel_relaxed(timer->match_mask, timer->control);
     59
     60		event_handler = READ_ONCE(timer->evt.event_handler);
     61		if (event_handler)
     62			event_handler(&timer->evt);
     63		return IRQ_HANDLED;
     64	} else {
     65		return IRQ_NONE;
     66	}
     67}
     68
     69static int __init bcm2835_timer_init(struct device_node *node)
     70{
     71	void __iomem *base;
     72	u32 freq;
     73	int irq, ret;
     74	struct bcm2835_timer *timer;
     75
     76	base = of_iomap(node, 0);
     77	if (!base) {
     78		pr_err("Can't remap registers\n");
     79		return -ENXIO;
     80	}
     81
     82	ret = of_property_read_u32(node, "clock-frequency", &freq);
     83	if (ret) {
     84		pr_err("Can't read clock-frequency\n");
     85		goto err_iounmap;
     86	}
     87
     88	system_clock = base + REG_COUNTER_LO;
     89	sched_clock_register(bcm2835_sched_read, 32, freq);
     90
     91	clocksource_mmio_init(base + REG_COUNTER_LO, node->name,
     92		freq, 300, 32, clocksource_mmio_readl_up);
     93
     94	irq = irq_of_parse_and_map(node, DEFAULT_TIMER);
     95	if (irq <= 0) {
     96		pr_err("Can't parse IRQ\n");
     97		ret = -EINVAL;
     98		goto err_iounmap;
     99	}
    100
    101	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
    102	if (!timer) {
    103		ret = -ENOMEM;
    104		goto err_iounmap;
    105	}
    106
    107	timer->control = base + REG_CONTROL;
    108	timer->compare = base + REG_COMPARE(DEFAULT_TIMER);
    109	timer->match_mask = BIT(DEFAULT_TIMER);
    110	timer->evt.name = node->name;
    111	timer->evt.rating = 300;
    112	timer->evt.features = CLOCK_EVT_FEAT_ONESHOT;
    113	timer->evt.set_next_event = bcm2835_time_set_next_event;
    114	timer->evt.cpumask = cpumask_of(0);
    115
    116	ret = request_irq(irq, bcm2835_time_interrupt, IRQF_TIMER | IRQF_SHARED,
    117			  node->name, timer);
    118	if (ret) {
    119		pr_err("Can't set up timer IRQ\n");
    120		goto err_timer_free;
    121	}
    122
    123	clockevents_config_and_register(&timer->evt, freq, 0xf, 0xffffffff);
    124
    125	pr_info("bcm2835: system timer (irq = %d)\n", irq);
    126
    127	return 0;
    128
    129err_timer_free:
    130	kfree(timer);
    131
    132err_iounmap:
    133	iounmap(base);
    134	return ret;
    135}
    136TIMER_OF_DECLARE(bcm2835, "brcm,bcm2835-system-timer",
    137			bcm2835_timer_init);