projects/linux·blob v6.6 · refs

150 lines · 3.1 KiB

1// SPDX-License-Identifier: GPL-2.0+
2//
3// Copyright 2017-2019 NXP
4
5#include <linux/interrupt.h>
6#include <linux/clockchips.h>
7
8#include "timer-of.h"
9
10#define CMP_OFFSET 0x10000
11
12#define CNTCV_LO 0x8
13#define CNTCV_HI 0xc
14#define CMPCV_LO (CMP_OFFSET + 0x20)
15#define CMPCV_HI (CMP_OFFSET + 0x24)
16#define CMPCR (CMP_OFFSET + 0x2c)
17
18#define SYS_CTR_EN 0x1
19#define SYS_CTR_IRQ_MASK 0x2
20
21#define SYS_CTR_CLK_DIV 0x3
22
23static void __iomem *sys_ctr_base __ro_after_init;
24static u32 cmpcr __ro_after_init;
25
26static void sysctr_timer_enable(bool enable)
27{
28 writel(enable ? cmpcr | SYS_CTR_EN : cmpcr, sys_ctr_base + CMPCR);
29}
30
31static void sysctr_irq_acknowledge(void)
32{
33 /*
34 * clear the enable bit(EN =0) will clear
35 * the status bit(ISTAT = 0), then the interrupt
36 * signal will be negated(acknowledged).
37 */
38 sysctr_timer_enable(false);
39}
40
41static inline u64 sysctr_read_counter(void)
42{
43 u32 cnt_hi, tmp_hi, cnt_lo;
44
45 do {
46 cnt_hi = readl_relaxed(sys_ctr_base + CNTCV_HI);
47 cnt_lo = readl_relaxed(sys_ctr_base + CNTCV_LO);
48 tmp_hi = readl_relaxed(sys_ctr_base + CNTCV_HI);
49 } while (tmp_hi != cnt_hi);
50
51 return ((u64) cnt_hi << 32) | cnt_lo;
52}
53
54static int sysctr_set_next_event(unsigned long delta,
55 struct clock_event_device *evt)
56{
57 u32 cmp_hi, cmp_lo;
58 u64 next;
59
60 sysctr_timer_enable(false);
61
62 next = sysctr_read_counter();
63
64 next += delta;
65
66 cmp_hi = (next >> 32) & 0x00fffff;
67 cmp_lo = next & 0xffffffff;
68
69 writel_relaxed(cmp_hi, sys_ctr_base + CMPCV_HI);
70 writel_relaxed(cmp_lo, sys_ctr_base + CMPCV_LO);
71
72 sysctr_timer_enable(true);
73
74 return 0;
75}
76
77static int sysctr_set_state_oneshot(struct clock_event_device *evt)
78{
79 return 0;
80}
81
82static int sysctr_set_state_shutdown(struct clock_event_device *evt)
83{
84 sysctr_timer_enable(false);
85
86 return 0;
87}
88
89static irqreturn_t sysctr_timer_interrupt(int irq, void *dev_id)
90{
91 struct clock_event_device *evt = dev_id;
92
93 sysctr_irq_acknowledge();
94
95 evt->event_handler(evt);
96
97 return IRQ_HANDLED;
98}
99
100static struct timer_of to_sysctr = {
101 .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
102 .clkevt = {
103 .name = "i.MX system counter timer",
104 .features = CLOCK_EVT_FEAT_ONESHOT |
105 CLOCK_EVT_FEAT_DYNIRQ,
106 .set_state_oneshot = sysctr_set_state_oneshot,
107 .set_next_event = sysctr_set_next_event,
108 .set_state_shutdown = sysctr_set_state_shutdown,
109 .rating = 200,
110 },
111 .of_irq = {
112 .handler = sysctr_timer_interrupt,
113 .flags = IRQF_TIMER,
114 },
115 .of_clk = {
116 .name = "per",
117 },
118};
119
120static void __init sysctr_clockevent_init(void)
121{
122 to_sysctr.clkevt.cpumask = cpu_possible_mask;
123
124 clockevents_config_and_register(&to_sysctr.clkevt,
125 timer_of_rate(&to_sysctr),
126 0xff, 0x7fffffff);
127}
128
129static int __init sysctr_timer_init(struct device_node *np)
130{
131 int ret = 0;
132
133 ret = timer_of_init(np, &to_sysctr);
134 if (ret)
135 return ret;
136
137 if (!of_property_read_bool(np, "nxp,no-divider")) {
138 /* system counter clock is divided by 3 internally */
139 to_sysctr.of_clk.rate /= SYS_CTR_CLK_DIV;
140 }
141
142 sys_ctr_base = timer_of_base(&to_sysctr);
143 cmpcr = readl(sys_ctr_base + CMPCR);
144 cmpcr &= ~SYS_CTR_EN;
145
146 sysctr_clockevent_init();
147
148 return 0;
149}
150TIMER_OF_DECLARE(sysctr_timer, "nxp,sysctr-timer", sysctr_timer_init);