summaryrefslogtreecommitdiffstats
path: root/drivers/clocksource/timer-atlas7.c
blob: 62c4bbc55a7eaede06350bed31f3275dfaddefe8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
/*
 * System timer for CSR SiRFprimaII
 *
 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
 *
 * Licensed under GPLv2 or later.
 */

#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/cpu.h>
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/sched_clock.h>

#define SIRFSOC_TIMER_32COUNTER_0_CTRL			0x0000
#define SIRFSOC_TIMER_32COUNTER_1_CTRL			0x0004
#define SIRFSOC_TIMER_MATCH_0				0x0018
#define SIRFSOC_TIMER_MATCH_1				0x001c
#define SIRFSOC_TIMER_COUNTER_0				0x0048
#define SIRFSOC_TIMER_COUNTER_1				0x004c
#define SIRFSOC_TIMER_INTR_STATUS			0x0060
#define SIRFSOC_TIMER_WATCHDOG_EN			0x0064
#define SIRFSOC_TIMER_64COUNTER_CTRL			0x0068
#define SIRFSOC_TIMER_64COUNTER_LO			0x006c
#define SIRFSOC_TIMER_64COUNTER_HI			0x0070
#define SIRFSOC_TIMER_64COUNTER_LOAD_LO			0x0074
#define SIRFSOC_TIMER_64COUNTER_LOAD_HI			0x0078
#define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO		0x007c
#define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI		0x0080

#define SIRFSOC_TIMER_REG_CNT 6

static unsigned long atlas7_timer_rate;

static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
	SIRFSOC_TIMER_WATCHDOG_EN,
	SIRFSOC_TIMER_32COUNTER_0_CTRL,
	SIRFSOC_TIMER_32COUNTER_1_CTRL,
	SIRFSOC_TIMER_64COUNTER_CTRL,
	SIRFSOC_TIMER_64COUNTER_RLATCHED_LO,
	SIRFSOC_TIMER_64COUNTER_RLATCHED_HI,
};

static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];

static void __iomem *sirfsoc_timer_base;

/* disable count and interrupt */
static inline void sirfsoc_timer_count_disable(int idx)
{
	writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) & ~0x7,
		sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
}

/* enable count and interrupt */
static inline void sirfsoc_timer_count_enable(int idx)
{
	writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) | 0x3,
		sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
}

/* timer interrupt handler */
static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *ce = dev_id;
	int cpu = smp_processor_id();

	/* clear timer interrupt */
	writel_relaxed(BIT(cpu), sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);

	if (clockevent_state_oneshot(ce))
		sirfsoc_timer_count_disable(cpu);

	ce->event_handler(ce);

	return IRQ_HANDLED;
}

/* read 64-bit timer counter */
static u64 sirfsoc_timer_read(struct clocksource *cs)
{
	u64 cycles;

	writel_relaxed((readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
			BIT(0)) & ~BIT(1), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);

	cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI);
	cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO);

	return cycles;
}

static int sirfsoc_timer_set_next_event(unsigned long delta,
	struct clock_event_device *ce)
{
	int cpu = smp_processor_id();

	/* disable timer first, then modify the related registers */
	sirfsoc_timer_count_disable(cpu);

	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 +
		4 * cpu);
	writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 +
		4 * cpu);

	/* enable the tick */
	sirfsoc_timer_count_enable(cpu);

	return 0;
}

/* Oneshot is enabled in set_next_event */
static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
{
	sirfsoc_timer_count_disable(smp_processor_id());
	return 0;
}

static void sirfsoc_clocksource_suspend(struct clocksource *cs)
{
	int i;

	for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
		sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
}

static void sirfsoc_clocksource_resume(struct clocksource *cs)
{
	int i;

	for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
		writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);

	writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
		sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
	writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
		sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);

	writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
		BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
}

static struct clock_event_device __percpu *sirfsoc_clockevent;

static struct clocksource sirfsoc_clocksource = {
	.name = "sirfsoc_clocksource",
	.rating = 200,
	.mask = CLOCKSOURCE_MASK(64),
	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
	.read = sirfsoc_timer_read,
	.suspend = sirfsoc_clocksource_suspend,
	.resume = sirfsoc_clocksource_resume,
};

static struct irqaction sirfsoc_timer_irq = {
	.name = "sirfsoc_timer0",
	.flags = IRQF_TIMER | IRQF_NOBALANCING,
	.handler = sirfsoc_timer_interrupt,
};

static struct irqaction sirfsoc_timer1_irq = {
	.name = "sirfsoc_timer1",
	.flags = IRQF_TIMER | IRQF_NOBALANCING,
	.handler = sirfsoc_timer_interrupt,
};

static int sirfsoc_local_timer_starting_cpu(unsigned int cpu)
{
	struct clock_event_device *ce = per_cpu_ptr(sirfsoc_clockevent, cpu);
	struct irqaction *action;

	if (cpu == 0)
		action = &sirfsoc_timer_irq;
	else
		action = &sirfsoc_timer1_irq;

	ce->irq = action->irq;
	ce->name = "local_timer";
	ce->features = CLOCK_EVT_FEAT_ONESHOT;
	ce->rating = 200;
	ce->set_state_shutdown = sirfsoc_timer_shutdown;
	ce->set_state_oneshot = sirfsoc_timer_shutdown;
	ce->tick_resume = sirfsoc_timer_shutdown;
	ce->set_next_event = sirfsoc_timer_set_next_event;
	clockevents_calc_mult_shift(ce, atlas7_timer_rate, 60);
	ce->max_delta_ns = clockevent_delta2ns(-2, ce);
	ce->max_delta_ticks = (unsigned long)-2;
	ce->min_delta_ns = clockevent_delta2ns(2, ce);
	ce->min_delta_ticks = 2;
	ce->cpumask = cpumask_of(cpu);

	action->dev_id = ce;
	BUG_ON(setup_irq(ce->irq, action));
	irq_force_affinity(action->irq, cpumask_of(cpu));

	clockevents_register_device(ce);
	return 0;
}

static int sirfsoc_local_timer_dying_cpu(unsigned int cpu)
{
	sirfsoc_timer_count_disable(1);

	if (cpu == 0)
		remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
	else
		remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq);
	return 0;
}

static int __init sirfsoc_clockevent_init(void)
{
	sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
	BUG_ON(!sirfsoc_clockevent);

	/* Install and invoke hotplug callbacks */
	return cpuhp_setup_state(CPUHP_AP_MARCO_TIMER_STARTING,
				 "clockevents/marco:starting",
				 sirfsoc_local_timer_starting_cpu,
				 sirfsoc_local_timer_dying_cpu);
}

/* initialize the kernel jiffy timer source */
static int __init sirfsoc_atlas7_timer_init(struct device_node *np)
{
	struct clk *clk;

	clk = of_clk_get(np, 0);
	BUG_ON(IS_ERR(clk));

	BUG_ON(clk_prepare_enable(clk));

	atlas7_timer_rate = clk_get_rate(clk);

	/* timer dividers: 0, not divided */
	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);

	/* Initialize timer counters to 0 */
	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
	writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
		BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
	writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);

	/* Clear all interrupts */
	writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);

	BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate));

	return sirfsoc_clockevent_init();
}

static int __init sirfsoc_of_timer_init(struct device_node *np)
{
	sirfsoc_timer_base = of_iomap(np, 0);
	if (!sirfsoc_timer_base) {
		pr_err("unable to map timer cpu registers\n");
		return -ENXIO;
	}

	sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
	if (!sirfsoc_timer_irq.irq) {
		pr_err("No irq passed for timer0 via DT\n");
		return -EINVAL;
	}

	sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
	if (!sirfsoc_timer1_irq.irq) {
		pr_err("No irq passed for timer1 via DT\n");
		return -EINVAL;
	}

	return sirfsoc_atlas7_timer_init(np);
}
TIMER_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);
OpenPOWER on IntegriCloud