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);
174