1/*
2 * linux/arch/arm/mach-omap1/time.c
3 *
4 * OMAP Timers
5 *
6 * Copyright (C) 2004 Nokia Corporation
7 * Partial timer rewrite and additional dynamic tick timer support by
8 * Tony Lindgen <tony@atomide.com> and
9 * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
10 *
11 * MPU timer code based on the older MPU timer code for OMAP
12 * Copyright (C) 2000 RidgeRun, Inc.
13 * Author: Greg Lonnon <glonnon@ridgerun.com>
14 *
15 * This program is free software; you can redistribute it and/or modify it
16 * under the terms of the GNU General Public License as published by the
17 * Free Software Foundation; either version 2 of the License, or (at your
18 * option) any later version.
19 *
20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
21 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
23 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
26 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
27 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 * You should have received a copy of the  GNU General Public License along
32 * with this program; if not, write  to the Free Software Foundation, Inc.,
33 * 675 Mass Ave, Cambridge, MA 02139, USA.
34 */
35
36#include <linux/kernel.h>
37#include <linux/init.h>
38#include <linux/delay.h>
39#include <linux/interrupt.h>
40#include <linux/spinlock.h>
41#include <linux/clk.h>
42#include <linux/err.h>
43#include <linux/clocksource.h>
44#include <linux/clockchips.h>
45#include <linux/io.h>
46#include <linux/sched_clock.h>
47
48#include <asm/irq.h>
49
50#include <mach/hardware.h>
51#include <asm/mach/irq.h>
52#include <asm/mach/time.h>
53
54#include "iomap.h"
55#include "common.h"
56
57#ifdef CONFIG_OMAP_MPU_TIMER
58
59#define OMAP_MPU_TIMER_BASE		OMAP_MPU_TIMER1_BASE
60#define OMAP_MPU_TIMER_OFFSET		0x100
61
62typedef struct {
63	u32 cntl;			/* CNTL_TIMER, R/W */
64	u32 load_tim;			/* LOAD_TIM,   W */
65	u32 read_tim;			/* READ_TIM,   R */
66} omap_mpu_timer_regs_t;
67
68#define omap_mpu_timer_base(n)							\
69((omap_mpu_timer_regs_t __iomem *)OMAP1_IO_ADDRESS(OMAP_MPU_TIMER_BASE +	\
70				 (n)*OMAP_MPU_TIMER_OFFSET))
71
72static inline unsigned long notrace omap_mpu_timer_read(int nr)
73{
74	omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
75	return readl(&timer->read_tim);
76}
77
78static inline void omap_mpu_set_autoreset(int nr)
79{
80	omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
81
82	writel(readl(&timer->cntl) | MPU_TIMER_AR, &timer->cntl);
83}
84
85static inline void omap_mpu_remove_autoreset(int nr)
86{
87	omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
88
89	writel(readl(&timer->cntl) & ~MPU_TIMER_AR, &timer->cntl);
90}
91
92static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
93					int autoreset)
94{
95	omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
96	unsigned int timerflags = MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST;
97
98	if (autoreset)
99		timerflags |= MPU_TIMER_AR;
100
101	writel(MPU_TIMER_CLOCK_ENABLE, &timer->cntl);
102	udelay(1);
103	writel(load_val, &timer->load_tim);
104        udelay(1);
105	writel(timerflags, &timer->cntl);
106}
107
108static inline void omap_mpu_timer_stop(int nr)
109{
110	omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
111
112	writel(readl(&timer->cntl) & ~MPU_TIMER_ST, &timer->cntl);
113}
114
115/*
116 * ---------------------------------------------------------------------------
117 * MPU timer 1 ... count down to zero, interrupt, reload
118 * ---------------------------------------------------------------------------
119 */
120static int omap_mpu_set_next_event(unsigned long cycles,
121				   struct clock_event_device *evt)
122{
123	omap_mpu_timer_start(0, cycles, 0);
124	return 0;
125}
126
127static void omap_mpu_set_mode(enum clock_event_mode mode,
128			      struct clock_event_device *evt)
129{
130	switch (mode) {
131	case CLOCK_EVT_MODE_PERIODIC:
132		omap_mpu_set_autoreset(0);
133		break;
134	case CLOCK_EVT_MODE_ONESHOT:
135		omap_mpu_timer_stop(0);
136		omap_mpu_remove_autoreset(0);
137		break;
138	case CLOCK_EVT_MODE_UNUSED:
139	case CLOCK_EVT_MODE_SHUTDOWN:
140	case CLOCK_EVT_MODE_RESUME:
141		break;
142	}
143}
144
145static struct clock_event_device clockevent_mpu_timer1 = {
146	.name		= "mpu_timer1",
147	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
148	.set_next_event	= omap_mpu_set_next_event,
149	.set_mode	= omap_mpu_set_mode,
150};
151
152static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
153{
154	struct clock_event_device *evt = &clockevent_mpu_timer1;
155
156	evt->event_handler(evt);
157
158	return IRQ_HANDLED;
159}
160
161static struct irqaction omap_mpu_timer1_irq = {
162	.name		= "mpu_timer1",
163	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
164	.handler	= omap_mpu_timer1_interrupt,
165};
166
167static __init void omap_init_mpu_timer(unsigned long rate)
168{
169	setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
170	omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
171
172	clockevent_mpu_timer1.cpumask = cpumask_of(0);
173	clockevents_config_and_register(&clockevent_mpu_timer1, rate,
174					1, -1);
175}
176
177
178/*
179 * ---------------------------------------------------------------------------
180 * MPU timer 2 ... free running 32-bit clock source and scheduler clock
181 * ---------------------------------------------------------------------------
182 */
183
184static u64 notrace omap_mpu_read_sched_clock(void)
185{
186	return ~omap_mpu_timer_read(1);
187}
188
189static void __init omap_init_clocksource(unsigned long rate)
190{
191	omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(1);
192	static char err[] __initdata = KERN_ERR
193			"%s: can't register clocksource!\n";
194
195	omap_mpu_timer_start(1, ~0, 1);
196	sched_clock_register(omap_mpu_read_sched_clock, 32, rate);
197
198	if (clocksource_mmio_init(&timer->read_tim, "mpu_timer2", rate,
199			300, 32, clocksource_mmio_readl_down))
200		printk(err, "mpu_timer2");
201}
202
203static void __init omap_mpu_timer_init(void)
204{
205	struct clk	*ck_ref = clk_get(NULL, "ck_ref");
206	unsigned long	rate;
207
208	BUG_ON(IS_ERR(ck_ref));
209
210	rate = clk_get_rate(ck_ref);
211	clk_put(ck_ref);
212
213	/* PTV = 0 */
214	rate /= 2;
215
216	omap_init_mpu_timer(rate);
217	omap_init_clocksource(rate);
218}
219
220#else
221static inline void omap_mpu_timer_init(void)
222{
223	pr_err("Bogus timer, should not happen\n");
224}
225#endif	/* CONFIG_OMAP_MPU_TIMER */
226
227/*
228 * ---------------------------------------------------------------------------
229 * Timer initialization
230 * ---------------------------------------------------------------------------
231 */
232void __init omap1_timer_init(void)
233{
234	if (omap_32k_timer_init() != 0)
235		omap_mpu_timer_init();
236}
237