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64db8bb1 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
ee4af569 SA |
2 | /* |
3 | * Copyright 2012 Simon Arlott | |
ee4af569 SA |
4 | */ |
5 | ||
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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> | |
38ff87f7 | 18 | #include <linux/sched_clock.h> |
ee4af569 | 19 | |
ee4af569 SA |
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 | ||
29 | struct bcm2835_timer { | |
30 | void __iomem *control; | |
31 | void __iomem *compare; | |
32 | int match_mask; | |
33 | struct clock_event_device evt; | |
ee4af569 SA |
34 | }; |
35 | ||
36 | static void __iomem *system_clock __read_mostly; | |
37 | ||
18952f20 | 38 | static u64 notrace bcm2835_sched_read(void) |
ee4af569 SA |
39 | { |
40 | return readl_relaxed(system_clock); | |
41 | } | |
42 | ||
ee4af569 SA |
43 | static 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 | ||
53 | static 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 | ||
6aa7de05 | 60 | event_handler = READ_ONCE(timer->evt.event_handler); |
ee4af569 SA |
61 | if (event_handler) |
62 | event_handler(&timer->evt); | |
63 | return IRQ_HANDLED; | |
64 | } else { | |
65 | return IRQ_NONE; | |
66 | } | |
67 | } | |
68 | ||
524a7f08 | 69 | static int __init bcm2835_timer_init(struct device_node *node) |
ee4af569 | 70 | { |
ee4af569 SA |
71 | void __iomem *base; |
72 | u32 freq; | |
524a7f08 | 73 | int irq, ret; |
ee4af569 SA |
74 | struct bcm2835_timer *timer; |
75 | ||
ee4af569 | 76 | base = of_iomap(node, 0); |
524a7f08 | 77 | if (!base) { |
ac9ce6d1 | 78 | pr_err("Can't remap registers\n"); |
524a7f08 DL |
79 | return -ENXIO; |
80 | } | |
ee4af569 | 81 | |
524a7f08 DL |
82 | ret = of_property_read_u32(node, "clock-frequency", &freq); |
83 | if (ret) { | |
ac9ce6d1 | 84 | pr_err("Can't read clock-frequency\n"); |
84c39b8b | 85 | goto err_iounmap; |
524a7f08 | 86 | } |
ee4af569 SA |
87 | |
88 | system_clock = base + REG_COUNTER_LO; | |
18952f20 | 89 | sched_clock_register(bcm2835_sched_read, 32, freq); |
ee4af569 SA |
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); | |
524a7f08 | 95 | if (irq <= 0) { |
ac9ce6d1 | 96 | pr_err("Can't parse IRQ\n"); |
84c39b8b AY |
97 | ret = -EINVAL; |
98 | goto err_iounmap; | |
524a7f08 | 99 | } |
ee4af569 SA |
100 | |
101 | timer = kzalloc(sizeof(*timer), GFP_KERNEL); | |
524a7f08 | 102 | if (!timer) { |
84c39b8b AY |
103 | ret = -ENOMEM; |
104 | goto err_iounmap; | |
524a7f08 | 105 | } |
ee4af569 SA |
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; | |
ee4af569 SA |
113 | timer->evt.set_next_event = bcm2835_time_set_next_event; |
114 | timer->evt.cpumask = cpumask_of(0); | |
ee4af569 | 115 | |
cc2550b4 | 116 | ret = request_irq(irq, bcm2835_time_interrupt, IRQF_TIMER | IRQF_SHARED, |
117 | node->name, timer); | |
524a7f08 DL |
118 | if (ret) { |
119 | pr_err("Can't set up timer IRQ\n"); | |
2052d032 | 120 | goto err_timer_free; |
524a7f08 | 121 | } |
ee4af569 SA |
122 | |
123 | clockevents_config_and_register(&timer->evt, freq, 0xf, 0xffffffff); | |
124 | ||
125 | pr_info("bcm2835: system timer (irq = %d)\n", irq); | |
524a7f08 DL |
126 | |
127 | return 0; | |
84c39b8b | 128 | |
2052d032 CIK |
129 | err_timer_free: |
130 | kfree(timer); | |
131 | ||
84c39b8b AY |
132 | err_iounmap: |
133 | iounmap(base); | |
134 | return ret; | |
ee4af569 | 135 | } |
17273395 | 136 | TIMER_OF_DECLARE(bcm2835, "brcm,bcm2835-system-timer", |
c1b724f6 | 137 | bcm2835_timer_init); |