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173 lines · 3.7 KiB

1// SPDX-License-Identifier: GPL-2.0
2// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
3
4#include <linux/init.h>
5#include <linux/interrupt.h>
6#include <linux/sched_clock.h>
7#include <linux/cpu.h>
8#include <linux/of_irq.h>
9#include <asm/reg_ops.h>
10
11#include "timer-of.h"
12
13#define PTIM_CCVR "cr<3, 14>"
14#define PTIM_CTLR "cr<0, 14>"
15#define PTIM_LVR "cr<6, 14>"
16#define PTIM_TSR "cr<1, 14>"
17
18static int csky_mptimer_irq;
19
20static int csky_mptimer_set_next_event(unsigned long delta,
21 struct clock_event_device *ce)
22{
23 mtcr(PTIM_LVR, delta);
24
25 return 0;
26}
27
28static int csky_mptimer_shutdown(struct clock_event_device *ce)
29{
30 mtcr(PTIM_CTLR, 0);
31
32 return 0;
33}
34
35static int csky_mptimer_oneshot(struct clock_event_device *ce)
36{
37 mtcr(PTIM_CTLR, 1);
38
39 return 0;
40}
41
42static int csky_mptimer_oneshot_stopped(struct clock_event_device *ce)
43{
44 mtcr(PTIM_CTLR, 0);
45
46 return 0;
47}
48
49static DEFINE_PER_CPU(struct timer_of, csky_to) = {
50 .flags = TIMER_OF_CLOCK,
51 .clkevt = {
52 .rating = 300,
53 .features = CLOCK_EVT_FEAT_PERCPU |
54 CLOCK_EVT_FEAT_ONESHOT,
55 .set_state_shutdown = csky_mptimer_shutdown,
56 .set_state_oneshot = csky_mptimer_oneshot,
57 .set_state_oneshot_stopped = csky_mptimer_oneshot_stopped,
58 .set_next_event = csky_mptimer_set_next_event,
59 },
60};
61
62static irqreturn_t csky_timer_interrupt(int irq, void *dev)
63{
64 struct timer_of *to = this_cpu_ptr(&csky_to);
65
66 mtcr(PTIM_TSR, 0);
67
68 to->clkevt.event_handler(&to->clkevt);
69
70 return IRQ_HANDLED;
71}
72
73/*
74 * clock event for percpu
75 */
76static int csky_mptimer_starting_cpu(unsigned int cpu)
77{
78 struct timer_of *to = per_cpu_ptr(&csky_to, cpu);
79
80 to->clkevt.cpumask = cpumask_of(cpu);
81
82 enable_percpu_irq(csky_mptimer_irq, 0);
83
84 clockevents_config_and_register(&to->clkevt, timer_of_rate(to),
85 2, ULONG_MAX);
86
87 return 0;
88}
89
90static int csky_mptimer_dying_cpu(unsigned int cpu)
91{
92 disable_percpu_irq(csky_mptimer_irq);
93
94 return 0;
95}
96
97/*
98 * clock source
99 */
100static u64 notrace sched_clock_read(void)
101{
102 return (u64)mfcr(PTIM_CCVR);
103}
104
105static u64 clksrc_read(struct clocksource *c)
106{
107 return (u64)mfcr(PTIM_CCVR);
108}
109
110struct clocksource csky_clocksource = {
111 .name = "csky",
112 .rating = 400,
113 .mask = CLOCKSOURCE_MASK(32),
114 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
115 .read = clksrc_read,
116};
117
118static int __init csky_mptimer_init(struct device_node *np)
119{
120 int ret, cpu, cpu_rollback;
121 struct timer_of *to = NULL;
122
123 /*
124 * Csky_mptimer is designed for C-SKY SMP multi-processors and
125 * every core has it's own private irq and regs for clkevt and
126 * clksrc.
127 *
128 * The regs is accessed by cpu instruction: mfcr/mtcr instead of
129 * mmio map style. So we needn't mmio-address in dts, but we still
130 * need to give clk and irq number.
131 *
132 * We use private irq for the mptimer and irq number is the same
133 * for every core. So we use request_percpu_irq() in timer_of_init.
134 */
135 csky_mptimer_irq = irq_of_parse_and_map(np, 0);
136 if (csky_mptimer_irq <= 0)
137 return -EINVAL;
138
139 ret = request_percpu_irq(csky_mptimer_irq, csky_timer_interrupt,
140 "csky_mp_timer", &csky_to);
141 if (ret)
142 return -EINVAL;
143
144 for_each_possible_cpu(cpu) {
145 to = per_cpu_ptr(&csky_to, cpu);
146 ret = timer_of_init(np, to);
147 if (ret)
148 goto rollback;
149 }
150
151 clocksource_register_hz(&csky_clocksource, timer_of_rate(to));
152 sched_clock_register(sched_clock_read, 32, timer_of_rate(to));
153
154 ret = cpuhp_setup_state(CPUHP_AP_CSKY_TIMER_STARTING,
155 "clockevents/csky/timer:starting",
156 csky_mptimer_starting_cpu,
157 csky_mptimer_dying_cpu);
158 if (ret)
159 return -EINVAL;
160
161 return 0;
162
163rollback:
164 for_each_possible_cpu(cpu_rollback) {
165 if (cpu_rollback == cpu)
166 break;
167
168 to = per_cpu_ptr(&csky_to, cpu_rollback);
169 timer_of_cleanup(to);
170 }
171 return -EINVAL;
172}
173TIMER_OF_DECLARE(csky_mptimer, "csky,mptimer", csky_mptimer_init);