aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/clocksource/mxs_timer.c
blob: 02af4204af867e8f1b0796dc205df8fd4c204953 (plain) (blame)
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
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
/*
 *  Copyright (C) 2000-2001 Deep Blue Solutions
 *  Copyright (C) 2002 Shane Nay (shane@minirl.com)
 *  Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
 *  Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
 *  Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */

#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/stmp_device.h>

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

/*
 * There are 2 versions of the timrot on Freescale MXS-based SoCs.
 * The v1 on MX23 only gets 16 bits counter, while v2 on MX28
 * extends the counter to 32 bits.
 *
 * The implementation uses two timers, one for clock_event and
 * another for clocksource. MX28 uses timrot 0 and 1, while MX23
 * uses 0 and 2.
 */

#define MX23_TIMROT_VERSION_OFFSET	0x0a0
#define MX28_TIMROT_VERSION_OFFSET	0x120
#define BP_TIMROT_MAJOR_VERSION		24
#define BV_TIMROT_VERSION_1		0x01
#define BV_TIMROT_VERSION_2		0x02
#define timrot_is_v1()	(timrot_major_version == BV_TIMROT_VERSION_1)

/*
 * There are 4 registers for each timrotv2 instance, and 2 registers
 * for each timrotv1. So address step 0x40 in macros below strides
 * one instance of timrotv2 while two instances of timrotv1.
 *
 * As the result, HW_TIMROT_XXXn(1) defines the address of timrot1
 * on MX28 while timrot2 on MX23.
 */
/* common between v1 and v2 */
#define HW_TIMROT_ROTCTRL		0x00
#define HW_TIMROT_TIMCTRLn(n)		(0x20 + (n) * 0x40)
/* v1 only */
#define HW_TIMROT_TIMCOUNTn(n)		(0x30 + (n) * 0x40)
/* v2 only */
#define HW_TIMROT_RUNNING_COUNTn(n)	(0x30 + (n) * 0x40)
#define HW_TIMROT_FIXED_COUNTn(n)	(0x40 + (n) * 0x40)

#define BM_TIMROT_TIMCTRLn_RELOAD	(1 << 6)
#define BM_TIMROT_TIMCTRLn_UPDATE	(1 << 7)
#define BM_TIMROT_TIMCTRLn_IRQ_EN	(1 << 14)
#define BM_TIMROT_TIMCTRLn_IRQ		(1 << 15)
#define BP_TIMROT_TIMCTRLn_SELECT	0
#define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL		0x8
#define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL		0xb
#define BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS	0xf

static struct clock_event_device mxs_clockevent_device;
static enum clock_event_mode mxs_clockevent_mode = CLOCK_EVT_MODE_UNUSED;

static void __iomem *mxs_timrot_base;
static u32 timrot_major_version;

static inline void timrot_irq_disable(void)
{
	__raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
		     HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
}

static inline void timrot_irq_enable(void)
{
	__raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
		     HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_SET);
}

static void timrot_irq_acknowledge(void)
{
	__raw_writel(BM_TIMROT_TIMCTRLn_IRQ, mxs_timrot_base +
		     HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
}

static cycle_t timrotv1_get_cycles(struct clocksource *cs)
{
	return ~((__raw_readl(mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1))
			& 0xffff0000) >> 16);
}

static int timrotv1_set_next_event(unsigned long evt,
					struct clock_event_device *dev)
{
	/* timrot decrements the count */
	__raw_writel(evt, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(0));

	return 0;
}

static int timrotv2_set_next_event(unsigned long evt,
					struct clock_event_device *dev)
{
	/* timrot decrements the count */
	__raw_writel(evt, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(0));

	return 0;
}

static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = dev_id;

	timrot_irq_acknowledge();
	evt->event_handler(evt);

	return IRQ_HANDLED;
}

static struct irqaction mxs_timer_irq = {
	.name		= "MXS Timer Tick",
	.dev_id		= &mxs_clockevent_device,
	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
	.handler	= mxs_timer_interrupt,
};

#ifdef DEBUG
static const char *clock_event_mode_label[] const = {
	[CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
	[CLOCK_EVT_MODE_ONESHOT]  = "CLOCK_EVT_MODE_ONESHOT",
	[CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
	[CLOCK_EVT_MODE_UNUSED]   = "CLOCK_EVT_MODE_UNUSED"
};
#endif /* DEBUG */

static void mxs_set_mode(enum clock_event_mode mode,
				struct clock_event_device *evt)
{
	/* Disable interrupt in timer module */
	timrot_irq_disable();

	if (mode != mxs_clockevent_mode) {
		/* Set event time into the furthest future */
		if (timrot_is_v1())
			__raw_writel(0xffff,
				mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
		else
			__raw_writel(0xffffffff,
				mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));

		/* Clear pending interrupt */
		timrot_irq_acknowledge();
	}

#ifdef DEBUG
	pr_info("%s: changing mode from %s to %s\n", __func__,
		clock_event_mode_label[mxs_clockevent_mode],
		clock_event_mode_label[mode]);
#endif /* DEBUG */

	/* Remember timer mode */
	mxs_clockevent_mode = mode;

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		pr_err("%s: Periodic mode is not implemented\n", __func__);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		timrot_irq_enable();
		break;
	case CLOCK_EVT_MODE_SHUTDOWN:
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_RESUME:
		/* Left event sources disabled, no more interrupts appear */
		break;
	}
}

static struct clock_event_device mxs_clockevent_device = {
	.name		= "mxs_timrot",
	.features	= CLOCK_EVT_FEAT_ONESHOT,
	.set_mode	= mxs_set_mode,
	.set_next_event	= timrotv2_set_next_event,
	.rating		= 200,
};

static int __init mxs_clockevent_init(struct clk *timer_clk)
{
	if (timrot_is_v1())
		mxs_clockevent_device.set_next_event = timrotv1_set_next_event;
	mxs_clockevent_device.cpumask = cpumask_of(0);
	clockevents_config_and_register(&mxs_clockevent_device,
					clk_get_rate(timer_clk),
					timrot_is_v1() ? 0xf : 0x2,
					timrot_is_v1() ? 0xfffe : 0xfffffffe);

	return 0;
}

static struct clocksource clocksource_mxs = {
	.name		= "mxs_timer",
	.rating		= 200,
	.read		= timrotv1_get_cycles,
	.mask		= CLOCKSOURCE_MASK(16),
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

static u32 notrace mxs_read_sched_clock_v2(void)
{
	return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
}

static int __init mxs_clocksource_init(struct clk *timer_clk)
{
	unsigned int c = clk_get_rate(timer_clk);

	if (timrot_is_v1())
		clocksource_register_hz(&clocksource_mxs, c);
	else {
		clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
			"mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
		setup_sched_clock(mxs_read_sched_clock_v2, 32, c);
	}

	return 0;
}

static void __init mxs_timer_init(struct device_node *np)
{
	struct clk *timer_clk;
	int irq;

	mxs_timrot_base = of_iomap(np, 0);
	WARN_ON(!mxs_timrot_base);

	timer_clk = of_clk_get(np, 0);
	if (IS_ERR(timer_clk)) {
		pr_err("%s: failed to get clk\n", __func__);
		return;
	}

	clk_prepare_enable(timer_clk);

	/*
	 * Initialize timers to a known state
	 */
	stmp_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL);

	/* get timrot version */
	timrot_major_version = __raw_readl(mxs_timrot_base +
			(of_device_is_compatible(np, "fsl,imx23-timrot") ?
						MX23_TIMROT_VERSION_OFFSET :
						MX28_TIMROT_VERSION_OFFSET));
	timrot_major_version >>= BP_TIMROT_MAJOR_VERSION;

	/* one for clock_event */
	__raw_writel((timrot_is_v1() ?
			BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
			BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
			BM_TIMROT_TIMCTRLn_UPDATE |
			BM_TIMROT_TIMCTRLn_IRQ_EN,
			mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));

	/* another for clocksource */
	__raw_writel((timrot_is_v1() ?
			BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
			BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
			BM_TIMROT_TIMCTRLn_RELOAD,
			mxs_timrot_base + HW_TIMROT_TIMCTRLn(1));

	/* set clocksource timer fixed count to the maximum */
	if (timrot_is_v1())
		__raw_writel(0xffff,
			mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
	else
		__raw_writel(0xffffffff,
			mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));

	/* init and register the timer to the framework */
	mxs_clocksource_init(timer_clk);
	mxs_clockevent_init(timer_clk);

	/* Make irqs happen */
	irq = irq_of_parse_and_map(np, 0);
	setup_irq(irq, &mxs_timer_irq);
}
CLOCKSOURCE_OF_DECLARE(mxs, "fsl,timrot", mxs_timer_init);