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a7ad38b0 GR |
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 | ||
18 | static int csky_mptimer_irq; | |
19 | ||
20 | static 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 | ||
28 | static int csky_mptimer_shutdown(struct clock_event_device *ce) | |
29 | { | |
30 | mtcr(PTIM_CTLR, 0); | |
31 | ||
32 | return 0; | |
33 | } | |
34 | ||
35 | static int csky_mptimer_oneshot(struct clock_event_device *ce) | |
36 | { | |
37 | mtcr(PTIM_CTLR, 1); | |
38 | ||
39 | return 0; | |
40 | } | |
41 | ||
42 | static int csky_mptimer_oneshot_stopped(struct clock_event_device *ce) | |
43 | { | |
44 | mtcr(PTIM_CTLR, 0); | |
45 | ||
46 | return 0; | |
47 | } | |
48 | ||
49 | static 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 | ||
62 | static 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 | */ | |
76 | static 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 | ||
1d95fe4d GR |
82 | enable_percpu_irq(csky_mptimer_irq, 0); |
83 | ||
a7ad38b0 GR |
84 | clockevents_config_and_register(&to->clkevt, timer_of_rate(to), |
85 | 2, ULONG_MAX); | |
86 | ||
a7ad38b0 GR |
87 | return 0; |
88 | } | |
89 | ||
90 | static 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 | */ | |
0c87bb0e | 100 | static u64 notrace sched_clock_read(void) |
a7ad38b0 GR |
101 | { |
102 | return (u64)mfcr(PTIM_CCVR); | |
103 | } | |
104 | ||
105 | static u64 clksrc_read(struct clocksource *c) | |
106 | { | |
107 | return (u64)mfcr(PTIM_CCVR); | |
108 | } | |
109 | ||
110 | struct 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 | ||
118 | static 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 | ||
163 | rollback: | |
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 | } | |
173 | TIMER_OF_DECLARE(csky_mptimer, "csky,mptimer", csky_mptimer_init); |