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1da177e4 | 1 | /* |
3b59b6be | 2 | * linux/arch/arm/mach-omap1/time.c |
1da177e4 LT |
3 | * |
4 | * OMAP Timers | |
5 | * | |
6 | * Copyright (C) 2004 Nokia Corporation | |
b3402cf5 | 7 | * Partial timer rewrite and additional dynamic tick timer support by |
1da177e4 LT |
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 | ||
1da177e4 LT |
36 | #include <linux/kernel.h> |
37 | #include <linux/init.h> | |
38 | #include <linux/delay.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/sched.h> | |
41 | #include <linux/spinlock.h> | |
075192ae KH |
42 | #include <linux/clk.h> |
43 | #include <linux/err.h> | |
44 | #include <linux/clocksource.h> | |
45 | #include <linux/clockchips.h> | |
1da177e4 LT |
46 | |
47 | #include <asm/system.h> | |
48 | #include <asm/hardware.h> | |
49 | #include <asm/io.h> | |
50 | #include <asm/leds.h> | |
51 | #include <asm/irq.h> | |
52 | #include <asm/mach/irq.h> | |
53 | #include <asm/mach/time.h> | |
54 | ||
1da177e4 | 55 | |
1da177e4 LT |
56 | #define OMAP_MPU_TIMER_BASE OMAP_MPU_TIMER1_BASE |
57 | #define OMAP_MPU_TIMER_OFFSET 0x100 | |
58 | ||
1da177e4 LT |
59 | /* cycles to nsec conversions taken from arch/i386/kernel/timers/timer_tsc.c, |
60 | * converted to use kHz by Kevin Hilman */ | |
61 | /* convert from cycles(64bits) => nanoseconds (64bits) | |
62 | * basic equation: | |
63 | * ns = cycles / (freq / ns_per_sec) | |
64 | * ns = cycles * (ns_per_sec / freq) | |
65 | * ns = cycles * (10^9 / (cpu_khz * 10^3)) | |
66 | * ns = cycles * (10^6 / cpu_khz) | |
67 | * | |
68 | * Then we use scaling math (suggested by george at mvista.com) to get: | |
69 | * ns = cycles * (10^6 * SC / cpu_khz / SC | |
70 | * ns = cycles * cyc2ns_scale / SC | |
71 | * | |
72 | * And since SC is a constant power of two, we can convert the div | |
73 | * into a shift. | |
74 | * -johnstul at us.ibm.com "math is hard, lets go shopping!" | |
75 | */ | |
76 | static unsigned long cyc2ns_scale; | |
77 | #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ | |
78 | ||
79 | static inline void set_cyc2ns_scale(unsigned long cpu_khz) | |
80 | { | |
81 | cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz; | |
82 | } | |
83 | ||
84 | static inline unsigned long long cycles_2_ns(unsigned long long cyc) | |
85 | { | |
86 | return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR; | |
87 | } | |
88 | ||
1da177e4 LT |
89 | |
90 | typedef struct { | |
91 | u32 cntl; /* CNTL_TIMER, R/W */ | |
92 | u32 load_tim; /* LOAD_TIM, W */ | |
93 | u32 read_tim; /* READ_TIM, R */ | |
94 | } omap_mpu_timer_regs_t; | |
95 | ||
96 | #define omap_mpu_timer_base(n) \ | |
97 | ((volatile omap_mpu_timer_regs_t*)IO_ADDRESS(OMAP_MPU_TIMER_BASE + \ | |
98 | (n)*OMAP_MPU_TIMER_OFFSET)) | |
99 | ||
100 | static inline unsigned long omap_mpu_timer_read(int nr) | |
101 | { | |
102 | volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); | |
103 | return timer->read_tim; | |
104 | } | |
105 | ||
075192ae | 106 | static inline void omap_mpu_set_autoreset(int nr) |
1da177e4 LT |
107 | { |
108 | volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); | |
109 | ||
075192ae | 110 | timer->cntl = timer->cntl | MPU_TIMER_AR; |
1da177e4 LT |
111 | } |
112 | ||
075192ae | 113 | static inline void omap_mpu_remove_autoreset(int nr) |
1da177e4 | 114 | { |
075192ae | 115 | volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); |
1da177e4 | 116 | |
075192ae | 117 | timer->cntl = timer->cntl & ~MPU_TIMER_AR; |
1da177e4 LT |
118 | } |
119 | ||
075192ae KH |
120 | static inline void omap_mpu_timer_start(int nr, unsigned long load_val, |
121 | int autoreset) | |
122 | { | |
123 | volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); | |
124 | unsigned int timerflags = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST); | |
125 | ||
126 | if (autoreset) timerflags |= MPU_TIMER_AR; | |
127 | ||
128 | timer->cntl = MPU_TIMER_CLOCK_ENABLE; | |
129 | udelay(1); | |
130 | timer->load_tim = load_val; | |
131 | udelay(1); | |
132 | timer->cntl = timerflags; | |
133 | } | |
1da177e4 | 134 | |
06cad098 KH |
135 | static inline void omap_mpu_timer_stop(int nr) |
136 | { | |
137 | volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); | |
138 | ||
139 | timer->cntl &= ~MPU_TIMER_ST; | |
140 | } | |
141 | ||
1da177e4 | 142 | /* |
075192ae KH |
143 | * --------------------------------------------------------------------------- |
144 | * MPU timer 1 ... count down to zero, interrupt, reload | |
145 | * --------------------------------------------------------------------------- | |
1da177e4 | 146 | */ |
075192ae | 147 | static int omap_mpu_set_next_event(unsigned long cycles, |
06cad098 | 148 | struct clock_event_device *evt) |
1da177e4 | 149 | { |
075192ae KH |
150 | omap_mpu_timer_start(0, cycles, 0); |
151 | return 0; | |
152 | } | |
1da177e4 | 153 | |
075192ae KH |
154 | static void omap_mpu_set_mode(enum clock_event_mode mode, |
155 | struct clock_event_device *evt) | |
156 | { | |
157 | switch (mode) { | |
158 | case CLOCK_EVT_MODE_PERIODIC: | |
159 | omap_mpu_set_autoreset(0); | |
160 | break; | |
161 | case CLOCK_EVT_MODE_ONESHOT: | |
06cad098 | 162 | omap_mpu_timer_stop(0); |
075192ae KH |
163 | omap_mpu_remove_autoreset(0); |
164 | break; | |
165 | case CLOCK_EVT_MODE_UNUSED: | |
166 | case CLOCK_EVT_MODE_SHUTDOWN: | |
18de5bc4 | 167 | case CLOCK_EVT_MODE_RESUME: |
075192ae KH |
168 | break; |
169 | } | |
1da177e4 LT |
170 | } |
171 | ||
075192ae KH |
172 | static struct clock_event_device clockevent_mpu_timer1 = { |
173 | .name = "mpu_timer1", | |
174 | .features = CLOCK_EVT_FEAT_PERIODIC, CLOCK_EVT_FEAT_ONESHOT, | |
175 | .shift = 32, | |
176 | .set_next_event = omap_mpu_set_next_event, | |
177 | .set_mode = omap_mpu_set_mode, | |
178 | }; | |
179 | ||
180 | static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id) | |
1da177e4 | 181 | { |
075192ae | 182 | struct clock_event_device *evt = &clockevent_mpu_timer1; |
1da177e4 | 183 | |
075192ae | 184 | evt->event_handler(evt); |
1da177e4 LT |
185 | |
186 | return IRQ_HANDLED; | |
187 | } | |
188 | ||
075192ae KH |
189 | static struct irqaction omap_mpu_timer1_irq = { |
190 | .name = "mpu_timer1", | |
b30fabad | 191 | .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, |
075192ae | 192 | .handler = omap_mpu_timer1_interrupt, |
1da177e4 LT |
193 | }; |
194 | ||
075192ae KH |
195 | static __init void omap_init_mpu_timer(unsigned long rate) |
196 | { | |
197 | set_cyc2ns_scale(rate / 1000); | |
198 | ||
199 | setup_irq(INT_TIMER1, &omap_mpu_timer1_irq); | |
200 | omap_mpu_timer_start(0, (rate / HZ) - 1, 1); | |
201 | ||
202 | clockevent_mpu_timer1.mult = div_sc(rate, NSEC_PER_SEC, | |
203 | clockevent_mpu_timer1.shift); | |
204 | clockevent_mpu_timer1.max_delta_ns = | |
205 | clockevent_delta2ns(-1, &clockevent_mpu_timer1); | |
206 | clockevent_mpu_timer1.min_delta_ns = | |
207 | clockevent_delta2ns(1, &clockevent_mpu_timer1); | |
208 | ||
209 | clockevent_mpu_timer1.cpumask = cpumask_of_cpu(0); | |
210 | clockevents_register_device(&clockevent_mpu_timer1); | |
211 | } | |
212 | ||
213 | ||
214 | /* | |
215 | * --------------------------------------------------------------------------- | |
216 | * MPU timer 2 ... free running 32-bit clock source and scheduler clock | |
217 | * --------------------------------------------------------------------------- | |
218 | */ | |
219 | ||
220 | static unsigned long omap_mpu_timer2_overflows; | |
221 | ||
222 | static irqreturn_t omap_mpu_timer2_interrupt(int irq, void *dev_id) | |
1da177e4 | 223 | { |
075192ae | 224 | omap_mpu_timer2_overflows++; |
1da177e4 LT |
225 | return IRQ_HANDLED; |
226 | } | |
227 | ||
075192ae KH |
228 | static struct irqaction omap_mpu_timer2_irq = { |
229 | .name = "mpu_timer2", | |
52e405ea | 230 | .flags = IRQF_DISABLED, |
075192ae | 231 | .handler = omap_mpu_timer2_interrupt, |
1da177e4 LT |
232 | }; |
233 | ||
075192ae | 234 | static cycle_t mpu_read(void) |
1da177e4 | 235 | { |
075192ae KH |
236 | return ~omap_mpu_timer_read(1); |
237 | } | |
238 | ||
239 | static struct clocksource clocksource_mpu = { | |
240 | .name = "mpu_timer2", | |
241 | .rating = 300, | |
242 | .read = mpu_read, | |
243 | .mask = CLOCKSOURCE_MASK(32), | |
244 | .shift = 24, | |
245 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
246 | }; | |
247 | ||
248 | static void __init omap_init_clocksource(unsigned long rate) | |
249 | { | |
250 | static char err[] __initdata = KERN_ERR | |
251 | "%s: can't register clocksource!\n"; | |
252 | ||
253 | clocksource_mpu.mult | |
254 | = clocksource_khz2mult(rate/1000, clocksource_mpu.shift); | |
255 | ||
256 | setup_irq(INT_TIMER2, &omap_mpu_timer2_irq); | |
257 | omap_mpu_timer_start(1, ~0, 1); | |
258 | ||
259 | if (clocksource_register(&clocksource_mpu)) | |
260 | printk(err, clocksource_mpu.name); | |
1da177e4 LT |
261 | } |
262 | ||
075192ae | 263 | |
1da177e4 LT |
264 | /* |
265 | * Scheduler clock - returns current time in nanosec units. | |
266 | */ | |
267 | unsigned long long sched_clock(void) | |
268 | { | |
075192ae | 269 | unsigned long ticks = 0 - omap_mpu_timer_read(1); |
1da177e4 LT |
270 | unsigned long long ticks64; |
271 | ||
075192ae | 272 | ticks64 = omap_mpu_timer2_overflows; |
1da177e4 LT |
273 | ticks64 <<= 32; |
274 | ticks64 |= ticks; | |
275 | ||
276 | return cycles_2_ns(ticks64); | |
277 | } | |
1da177e4 LT |
278 | |
279 | /* | |
280 | * --------------------------------------------------------------------------- | |
281 | * Timer initialization | |
282 | * --------------------------------------------------------------------------- | |
283 | */ | |
3b59b6be | 284 | static void __init omap_timer_init(void) |
1da177e4 | 285 | { |
075192ae KH |
286 | struct clk *ck_ref = clk_get(NULL, "ck_ref"); |
287 | unsigned long rate; | |
288 | ||
289 | BUG_ON(IS_ERR(ck_ref)); | |
290 | ||
291 | rate = clk_get_rate(ck_ref); | |
292 | clk_put(ck_ref); | |
293 | ||
294 | /* PTV = 0 */ | |
295 | rate /= 2; | |
296 | ||
297 | omap_init_mpu_timer(rate); | |
298 | omap_init_clocksource(rate); | |
1da177e4 LT |
299 | } |
300 | ||
301 | struct sys_timer omap_timer = { | |
302 | .init = omap_timer_init, | |
1da177e4 | 303 | }; |