summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-tegra/timer.c
blob: 0fcb1eb4214dcfc9bb3d8891c23fa90f14b1a6bc (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
/*
 * arch/arch/mach-tegra/timer.c
 *
 * Copyright (C) 2010 Google, Inc.
 *
 * Author:
 *	Colin Cross <ccross@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/init.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/clk.h>
#include <linux/io.h>

#include <asm/mach/time.h>
#include <asm/localtimer.h>
#include <asm/sched_clock.h>

#include <mach/iomap.h>
#include <mach/irqs.h>
#include <mach/suspend.h>

#include "board.h"
#include "clock.h"

#define RTC_SECONDS            0x08
#define RTC_SHADOW_SECONDS     0x0c
#define RTC_MILLISECONDS       0x10

#define TIMERUS_CNTR_1US 0x10
#define TIMERUS_USEC_CFG 0x14
#define TIMERUS_CNTR_FREEZE 0x4c

#define TIMER1_BASE 0x0
#define TIMER2_BASE 0x8
#define TIMER3_BASE 0x50
#define TIMER4_BASE 0x58

#define TIMER_PTV 0x0
#define TIMER_PCR 0x4

static void __iomem *timer_reg_base = IO_ADDRESS(TEGRA_TMR1_BASE);
static void __iomem *rtc_base = IO_ADDRESS(TEGRA_RTC_BASE);

static struct timespec persistent_ts;
static u64 persistent_ms, last_persistent_ms;

#define timer_writel(value, reg) \
	__raw_writel(value, (u32)timer_reg_base + (reg))
#define timer_readl(reg) \
	__raw_readl((u32)timer_reg_base + (reg))

static int tegra_timer_set_next_event(unsigned long cycles,
					 struct clock_event_device *evt)
{
	u32 reg;

	reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
	timer_writel(reg, TIMER3_BASE + TIMER_PTV);

	return 0;
}

static void tegra_timer_set_mode(enum clock_event_mode mode,
				    struct clock_event_device *evt)
{
	u32 reg;

	timer_writel(0, TIMER3_BASE + TIMER_PTV);

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		reg = 0xC0000000 | ((1000000/HZ)-1);
		timer_writel(reg, TIMER3_BASE + TIMER_PTV);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	case CLOCK_EVT_MODE_RESUME:
		break;
	}
}

static cycle_t tegra_clocksource_read(struct clocksource *cs)
{
	return timer_readl(TIMERUS_CNTR_1US);
}

static struct clock_event_device tegra_clockevent = {
	.name		= "timer0",
	.rating		= 300,
	.features	= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
	.set_next_event	= tegra_timer_set_next_event,
	.set_mode	= tegra_timer_set_mode,
};

static struct clocksource tegra_clocksource = {
	.name	= "timer_us",
	.rating	= 300,
	.read	= tegra_clocksource_read,
	.mask	= CLOCKSOURCE_MASK(32),
	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
};

static DEFINE_CLOCK_DATA(cd);

/*
 * Constants generated by clocks_calc_mult_shift(m, s, 1MHz, NSEC_PER_SEC, 60).
 * This gives a resolution of about 1us and a wrap period of about 1h11min.
 */
#define SC_MULT		4194304000u
#define SC_SHIFT	22

unsigned long long notrace sched_clock(void)
{
	u32 cyc = timer_readl(TIMERUS_CNTR_1US);
	return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
}

static void notrace tegra_update_sched_clock(void)
{
	u32 cyc = timer_readl(TIMERUS_CNTR_1US);
	update_sched_clock(&cd, cyc, (u32)~0);
}

/*
 * tegra_rtc_read - Reads the Tegra RTC registers
 * Care must be taken that this funciton is not called while the
 * tegra_rtc driver could be executing to avoid race conditions
 * on the RTC shadow register
 */
u64 tegra_rtc_read_ms(void)
{
	u32 ms = readl(rtc_base + RTC_MILLISECONDS);
	u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
	return (u64)s * MSEC_PER_SEC + ms;
}

/*
 * read_persistent_clock -  Return time from a persistent clock.
 *
 * Reads the time from a source which isn't disabled during PM, the
 * 32k sync timer.  Convert the cycles elapsed since last read into
 * nsecs and adds to a monotonically increasing timespec.
 * Care must be taken that this funciton is not called while the
 * tegra_rtc driver could be executing to avoid race conditions
 * on the RTC shadow register
 */
void read_persistent_clock(struct timespec *ts)
{
	u64 delta;
	struct timespec *tsp = &persistent_ts;

	last_persistent_ms = persistent_ms;
	persistent_ms = tegra_rtc_read_ms();
	delta = persistent_ms - last_persistent_ms;

	timespec_add_ns(tsp, delta * NSEC_PER_MSEC);
	*ts = *tsp;
}

static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
	timer_writel(1<<30, TIMER3_BASE + TIMER_PCR);
	evt->event_handler(evt);
	return IRQ_HANDLED;
}

static struct irqaction tegra_timer_irq = {
	.name		= "timer0",
	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH,
	.handler	= tegra_timer_interrupt,
	.dev_id		= &tegra_clockevent,
	.irq		= INT_TMR3,
};

static void __init tegra_init_timer(void)
{
	struct clk *clk;
	unsigned long rate = clk_measure_input_freq();
	int ret;

	clk = clk_get_sys("timer", NULL);
	BUG_ON(IS_ERR(clk));
	clk_enable(clk);

	/*
	 * rtc registers are used by read_persistent_clock, keep the rtc clock
	 * enabled
	 */
	clk = clk_get_sys("rtc-tegra", NULL);
	BUG_ON(IS_ERR(clk));
	clk_enable(clk);

#ifdef CONFIG_HAVE_ARM_TWD
	twd_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x600);
#endif

	switch (rate) {
	case 12000000:
		timer_writel(0x000b, TIMERUS_USEC_CFG);
		break;
	case 13000000:
		timer_writel(0x000c, TIMERUS_USEC_CFG);
		break;
	case 19200000:
		timer_writel(0x045f, TIMERUS_USEC_CFG);
		break;
	case 26000000:
		timer_writel(0x0019, TIMERUS_USEC_CFG);
		break;
	default:
		WARN(1, "Unknown clock rate");
	}

	init_fixed_sched_clock(&cd, tegra_update_sched_clock, 32,
			       1000000, SC_MULT, SC_SHIFT);

	if (clocksource_register_hz(&tegra_clocksource, 1000000)) {
		printk(KERN_ERR "Failed to register clocksource\n");
		BUG();
	}

	ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
	if (ret) {
		printk(KERN_ERR "Failed to register timer IRQ: %d\n", ret);
		BUG();
	}

	clockevents_calc_mult_shift(&tegra_clockevent, 1000000, 5);
	tegra_clockevent.max_delta_ns =
		clockevent_delta2ns(0x1fffffff, &tegra_clockevent);
	tegra_clockevent.min_delta_ns =
		clockevent_delta2ns(0x1, &tegra_clockevent);
	tegra_clockevent.cpumask = cpu_all_mask;
	tegra_clockevent.irq = tegra_timer_irq.irq;
	clockevents_register_device(&tegra_clockevent);
}

struct sys_timer tegra_timer = {
	.init = tegra_init_timer,
};

#ifdef CONFIG_PM
static u32 usec_config;

void tegra_timer_suspend(void)
{
	usec_config = timer_readl(TIMERUS_USEC_CFG);
}

void tegra_timer_resume(void)
{
	timer_writel(usec_config, TIMERUS_USEC_CFG);
}
#endif
OpenPOWER on IntegriCloud