summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-omap2/timer-gp.c
blob: 7b7c2683ae7bb15cad4a2d32b4eab681884a0864 (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
/*
 * linux/arch/arm/mach-omap2/timer-gp.c
 *
 * OMAP2 GP timer support.
 *
 * Copyright (C) 2009 Nokia Corporation
 *
 * Update to use new clocksource/clockevent layers
 * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
 * Copyright (C) 2007 MontaVista Software, Inc.
 *
 * Original driver:
 * Copyright (C) 2005 Nokia Corporation
 * Author: Paul Mundt <paul.mundt@nokia.com>
 *         Juha Yrjölä <juha.yrjola@nokia.com>
 * OMAP Dual-mode timer framework support by Timo Teras
 *
 * Some parts based off of TI's 24xx code:
 *
 * Copyright (C) 2004-2009 Texas Instruments, Inc.
 *
 * Roughly modelled after the OMAP1 MPU timer code.
 * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>

#include <asm/mach/time.h>
#include <plat/dmtimer.h>
#include <asm/localtimer.h>

#include "timer-gp.h"

#include <plat/common.h>

/* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
#define MAX_GPTIMER_ID		12

static struct omap_dm_timer *gptimer;
static struct clock_event_device clockevent_gpt;
static u8 __initdata gptimer_id = 1;
static u8 __initdata inited;
struct omap_dm_timer *gptimer_wakeup;

static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
{
	struct omap_dm_timer *gpt = (struct omap_dm_timer *)dev_id;
	struct clock_event_device *evt = &clockevent_gpt;

	omap_dm_timer_write_status(gpt, OMAP_TIMER_INT_OVERFLOW);

	evt->event_handler(evt);
	return IRQ_HANDLED;
}

static struct irqaction omap2_gp_timer_irq = {
	.name		= "gp timer",
	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
	.handler	= omap2_gp_timer_interrupt,
};

static int omap2_gp_timer_set_next_event(unsigned long cycles,
					 struct clock_event_device *evt)
{
	omap_dm_timer_set_load_start(gptimer, 0, 0xffffffff - cycles);

	return 0;
}

static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
				    struct clock_event_device *evt)
{
	u32 period;

	omap_dm_timer_stop(gptimer);

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		period = clk_get_rate(omap_dm_timer_get_fclk(gptimer)) / HZ;
		period -= 1;
		omap_dm_timer_set_load_start(gptimer, 1, 0xffffffff - period);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	case CLOCK_EVT_MODE_RESUME:
		break;
	}
}

static struct clock_event_device clockevent_gpt = {
	.name		= "gp timer",
	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
	.shift		= 32,
	.set_next_event	= omap2_gp_timer_set_next_event,
	.set_mode	= omap2_gp_timer_set_mode,
};

/**
 * omap2_gp_clockevent_set_gptimer - set which GPTIMER is used for clockevents
 * @id: GPTIMER to use (1..MAX_GPTIMER_ID)
 *
 * Define the GPTIMER that the system should use for the tick timer.
 * Meant to be called from board-*.c files in the event that GPTIMER1, the
 * default, is unsuitable.  Returns -EINVAL on error or 0 on success.
 */
int __init omap2_gp_clockevent_set_gptimer(u8 id)
{
	if (id < 1 || id > MAX_GPTIMER_ID)
		return -EINVAL;

	BUG_ON(inited);

	gptimer_id = id;

	return 0;
}

static void __init omap2_gp_clockevent_init(void)
{
	u32 tick_rate;
	int src;

	inited = 1;

	gptimer = omap_dm_timer_request_specific(gptimer_id);
	BUG_ON(gptimer == NULL);
	gptimer_wakeup = gptimer;

#if defined(CONFIG_OMAP_32K_TIMER)
	src = OMAP_TIMER_SRC_32_KHZ;
#else
	src = OMAP_TIMER_SRC_SYS_CLK;
	WARN(gptimer_id == 12, "WARNING: GPTIMER12 can only use the "
	     "secure 32KiHz clock source\n");
#endif

	if (gptimer_id != 12)
		WARN(IS_ERR_VALUE(omap_dm_timer_set_source(gptimer, src)),
		     "timer-gp: omap_dm_timer_set_source() failed\n");

	tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gptimer));

	pr_info("OMAP clockevent source: GPTIMER%d at %u Hz\n",
		gptimer_id, tick_rate);

	omap2_gp_timer_irq.dev_id = (void *)gptimer;
	setup_irq(omap_dm_timer_get_irq(gptimer), &omap2_gp_timer_irq);
	omap_dm_timer_set_int_enable(gptimer, OMAP_TIMER_INT_OVERFLOW);

	clockevent_gpt.mult = div_sc(tick_rate, NSEC_PER_SEC,
				     clockevent_gpt.shift);
	clockevent_gpt.max_delta_ns =
		clockevent_delta2ns(0xffffffff, &clockevent_gpt);
	clockevent_gpt.min_delta_ns =
		clockevent_delta2ns(3, &clockevent_gpt);
		/* Timer internal resynch latency. */

	clockevent_gpt.cpumask = cpumask_of(0);
	clockevents_register_device(&clockevent_gpt);
}

/* Clocksource code */

#ifdef CONFIG_OMAP_32K_TIMER
/* 
 * When 32k-timer is enabled, don't use GPTimer for clocksource
 * instead, just leave default clocksource which uses the 32k
 * sync counter.  See clocksource setup in plat-omap/counter_32k.c
 */

static void __init omap2_gp_clocksource_init(void)
{
	omap_init_clocksource_32k();
}

#else
/*
 * clocksource
 */
static struct omap_dm_timer *gpt_clocksource;
static cycle_t clocksource_read_cycles(struct clocksource *cs)
{
	return (cycle_t)omap_dm_timer_read_counter(gpt_clocksource);
}

static struct clocksource clocksource_gpt = {
	.name		= "gp timer",
	.rating		= 300,
	.read		= clocksource_read_cycles,
	.mask		= CLOCKSOURCE_MASK(32),
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

/* Setup free-running counter for clocksource */
static void __init omap2_gp_clocksource_init(void)
{
	static struct omap_dm_timer *gpt;
	u32 tick_rate;
	static char err1[] __initdata = KERN_ERR
		"%s: failed to request dm-timer\n";
	static char err2[] __initdata = KERN_ERR
		"%s: can't register clocksource!\n";

	gpt = omap_dm_timer_request();
	if (!gpt)
		printk(err1, clocksource_gpt.name);
	gpt_clocksource = gpt;

	omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);
	tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));

	omap_dm_timer_set_load_start(gpt, 1, 0);

	if (clocksource_register_hz(&clocksource_gpt, tick_rate))
		printk(err2, clocksource_gpt.name);
}
#endif

static void __init omap2_gp_timer_init(void)
{
#ifdef CONFIG_LOCAL_TIMERS
	if (cpu_is_omap44xx()) {
		twd_base = ioremap(OMAP44XX_LOCAL_TWD_BASE, SZ_256);
		BUG_ON(!twd_base);
	}
#endif
	omap_dm_timer_init();

	omap2_gp_clockevent_init();
	omap2_gp_clocksource_init();
}

struct sys_timer omap_timer = {
	.init	= omap2_gp_timer_init,
};
OpenPOWER on IntegriCloud