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 <asm/mach/irq.h>
51#include <asm/mach/time.h>
52
53#include "hardware.h"
54#include "mux.h"
55#include "iomap.h"
56#include "common.h"
57#include "clock.h"
58
59#ifdef CONFIG_OMAP_MPU_TIMER
60
61#define OMAP_MPU_TIMER_BASE OMAP_MPU_TIMER1_BASE
62#define OMAP_MPU_TIMER_OFFSET 0x100
63
64typedef struct {
65 u32 cntl; /* CNTL_TIMER, R/W */
66 u32 load_tim; /* LOAD_TIM, W */
67 u32 read_tim; /* READ_TIM, R */
68} omap_mpu_timer_regs_t;
69
70#define omap_mpu_timer_base(n) \
71((omap_mpu_timer_regs_t __iomem *)OMAP1_IO_ADDRESS(OMAP_MPU_TIMER_BASE + \
72 (n)*OMAP_MPU_TIMER_OFFSET))
73
74static inline unsigned long notrace omap_mpu_timer_read(int nr)
75{
76 omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
77 return readl(&timer->read_tim);
78}
79
80static inline void omap_mpu_set_autoreset(int nr)
81{
82 omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
83
84 writel(readl(&timer->cntl) | MPU_TIMER_AR, &timer->cntl);
85}
86
87static inline void omap_mpu_remove_autoreset(int nr)
88{
89 omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
90
91 writel(readl(&timer->cntl) & ~MPU_TIMER_AR, &timer->cntl);
92}
93
94static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
95 int autoreset)
96{
97 omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
98 unsigned int timerflags = MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST;
99
100 if (autoreset)
101 timerflags |= MPU_TIMER_AR;
102
103 writel(MPU_TIMER_CLOCK_ENABLE, &timer->cntl);
104 udelay(1);
105 writel(load_val, &timer->load_tim);
106 udelay(1);
107 writel(timerflags, &timer->cntl);
108}
109
110static inline void omap_mpu_timer_stop(int nr)
111{
112 omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
113
114 writel(readl(&timer->cntl) & ~MPU_TIMER_ST, &timer->cntl);
115}
116
117/*
118 * ---------------------------------------------------------------------------
119 * MPU timer 1 ... count down to zero, interrupt, reload
120 * ---------------------------------------------------------------------------
121 */
122static int omap_mpu_set_next_event(unsigned long cycles,
123 struct clock_event_device *evt)
124{
125 omap_mpu_timer_start(0, cycles, 0);
126 return 0;
127}
128
129static int omap_mpu_set_oneshot(struct clock_event_device *evt)
130{
131 omap_mpu_timer_stop(0);
132 omap_mpu_remove_autoreset(0);
133 return 0;
134}
135
136static int omap_mpu_set_periodic(struct clock_event_device *evt)
137{
138 omap_mpu_set_autoreset(0);
139 return 0;
140}
141
142static struct clock_event_device clockevent_mpu_timer1 = {
143 .name = "mpu_timer1",
144 .features = CLOCK_EVT_FEAT_PERIODIC |
145 CLOCK_EVT_FEAT_ONESHOT,
146 .set_next_event = omap_mpu_set_next_event,
147 .set_state_periodic = omap_mpu_set_periodic,
148 .set_state_oneshot = omap_mpu_set_oneshot,
149};
150
151static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
152{
153 struct clock_event_device *evt = &clockevent_mpu_timer1;
154
155 evt->event_handler(evt);
156
157 return IRQ_HANDLED;
158}
159
160static __init void omap_init_mpu_timer(unsigned long rate)
161{
162 if (request_irq(INT_TIMER1, omap_mpu_timer1_interrupt,
163 IRQF_TIMER | IRQF_IRQPOLL, "mpu_timer1", NULL))
164 pr_err("Failed to request irq %d (mpu_timer1)\n", INT_TIMER1);
165 omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
166
167 clockevent_mpu_timer1.cpumask = cpumask_of(0);
168 clockevents_config_and_register(&clockevent_mpu_timer1, rate,
169 1, -1);
170}
171
172
173/*
174 * ---------------------------------------------------------------------------
175 * MPU timer 2 ... free running 32-bit clock source and scheduler clock
176 * ---------------------------------------------------------------------------
177 */
178
179static u64 notrace omap_mpu_read_sched_clock(void)
180{
181 return ~omap_mpu_timer_read(1);
182}
183
184static void __init omap_init_clocksource(unsigned long rate)
185{
186 omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(1);
187 static char err[] __initdata = KERN_ERR
188 "%s: can't register clocksource!\n";
189
190 omap_mpu_timer_start(1, ~0, 1);
191 sched_clock_register(omap_mpu_read_sched_clock, 32, rate);
192
193 if (clocksource_mmio_init(&timer->read_tim, "mpu_timer2", rate,
194 300, 32, clocksource_mmio_readl_down))
195 printk(err, "mpu_timer2");
196}
197
198static void __init omap_mpu_timer_init(void)
199{
200 struct clk *ck_ref = clk_get(NULL, "ck_ref");
201 unsigned long rate;
202
203 BUG_ON(IS_ERR(ck_ref));
204
205 rate = clk_get_rate(ck_ref);
206 clk_put(ck_ref);
207
208 /* PTV = 0 */
209 rate /= 2;
210
211 omap_init_mpu_timer(rate);
212 omap_init_clocksource(rate);
213}
214
215#else
216static inline void omap_mpu_timer_init(void)
217{
218 pr_err("Bogus timer, should not happen\n");
219}
220#endif /* CONFIG_OMAP_MPU_TIMER */
221
222/*
223 * ---------------------------------------------------------------------------
224 * Timer initialization
225 * ---------------------------------------------------------------------------
226 */
227void __init omap1_timer_init(void)
228{
229 omap1_clk_init();
230 omap1_mux_init();
231
232 if (omap_32k_timer_init() != 0)
233 omap_mpu_timer_init();
234}
235

source code of linux/arch/arm/mach-omap1/time.c