2 * arch/arch/mach-tegra/timer.c
4 * Copyright (C) 2010 Google, Inc.
7 * Colin Cross <ccross@google.com>
9 * This software is licensed under the terms of the GNU General Public
10 * License version 2, as published by the Free Software Foundation, and
11 * may be copied, distributed, and modified under those terms.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
20 #include <linux/init.h>
21 #include <linux/sched.h>
22 #include <linux/time.h>
23 #include <linux/interrupt.h>
24 #include <linux/irq.h>
25 #include <linux/clockchips.h>
26 #include <linux/clocksource.h>
27 #include <linux/clk.h>
30 #include <asm/mach/time.h>
31 #include <asm/localtimer.h>
32 #include <asm/sched_clock.h>
34 #include <mach/iomap.h>
35 #include <mach/irqs.h>
36 #include <mach/suspend.h>
41 #define RTC_SECONDS 0x08
42 #define RTC_SHADOW_SECONDS 0x0c
43 #define RTC_MILLISECONDS 0x10
45 #define TIMERUS_CNTR_1US 0x10
46 #define TIMERUS_USEC_CFG 0x14
47 #define TIMERUS_CNTR_FREEZE 0x4c
49 #define TIMER1_BASE 0x0
50 #define TIMER2_BASE 0x8
51 #define TIMER3_BASE 0x50
52 #define TIMER4_BASE 0x58
57 static void __iomem *timer_reg_base = IO_ADDRESS(TEGRA_TMR1_BASE);
58 static void __iomem *rtc_base = IO_ADDRESS(TEGRA_RTC_BASE);
60 static struct timespec persistent_ts;
61 static u64 persistent_ms, last_persistent_ms;
63 #define timer_writel(value, reg) \
64 __raw_writel(value, (u32)timer_reg_base + (reg))
65 #define timer_readl(reg) \
66 __raw_readl((u32)timer_reg_base + (reg))
68 static int tegra_timer_set_next_event(unsigned long cycles,
69 struct clock_event_device *evt)
73 reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
74 timer_writel(reg, TIMER3_BASE + TIMER_PTV);
79 static void tegra_timer_set_mode(enum clock_event_mode mode,
80 struct clock_event_device *evt)
84 timer_writel(0, TIMER3_BASE + TIMER_PTV);
87 case CLOCK_EVT_MODE_PERIODIC:
88 reg = 0xC0000000 | ((1000000/HZ)-1);
89 timer_writel(reg, TIMER3_BASE + TIMER_PTV);
91 case CLOCK_EVT_MODE_ONESHOT:
93 case CLOCK_EVT_MODE_UNUSED:
94 case CLOCK_EVT_MODE_SHUTDOWN:
95 case CLOCK_EVT_MODE_RESUME:
100 static cycle_t tegra_clocksource_read(struct clocksource *cs)
102 return timer_readl(TIMERUS_CNTR_1US);
105 static struct clock_event_device tegra_clockevent = {
108 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
109 .set_next_event = tegra_timer_set_next_event,
110 .set_mode = tegra_timer_set_mode,
113 static struct clocksource tegra_clocksource = {
116 .read = tegra_clocksource_read,
117 .mask = CLOCKSOURCE_MASK(32),
118 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
121 static DEFINE_CLOCK_DATA(cd);
124 * Constants generated by clocks_calc_mult_shift(m, s, 1MHz, NSEC_PER_SEC, 60).
125 * This gives a resolution of about 1us and a wrap period of about 1h11min.
127 #define SC_MULT 4194304000u
130 unsigned long long notrace sched_clock(void)
132 u32 cyc = timer_readl(TIMERUS_CNTR_1US);
133 return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
136 static void notrace tegra_update_sched_clock(void)
138 u32 cyc = timer_readl(TIMERUS_CNTR_1US);
139 update_sched_clock(&cd, cyc, (u32)~0);
143 * tegra_rtc_read - Reads the Tegra RTC registers
144 * Care must be taken that this funciton is not called while the
145 * tegra_rtc driver could be executing to avoid race conditions
146 * on the RTC shadow register
148 u64 tegra_rtc_read_ms(void)
150 u32 ms = readl(rtc_base + RTC_MILLISECONDS);
151 u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
152 return (u64)s * MSEC_PER_SEC + ms;
156 * read_persistent_clock - Return time from a persistent clock.
158 * Reads the time from a source which isn't disabled during PM, the
159 * 32k sync timer. Convert the cycles elapsed since last read into
160 * nsecs and adds to a monotonically increasing timespec.
161 * Care must be taken that this funciton is not called while the
162 * tegra_rtc driver could be executing to avoid race conditions
163 * on the RTC shadow register
165 void read_persistent_clock(struct timespec *ts)
168 struct timespec *tsp = &persistent_ts;
170 last_persistent_ms = persistent_ms;
171 persistent_ms = tegra_rtc_read_ms();
172 delta = persistent_ms - last_persistent_ms;
174 timespec_add_ns(tsp, delta * NSEC_PER_MSEC);
178 static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
180 struct clock_event_device *evt = (struct clock_event_device *)dev_id;
181 timer_writel(1<<30, TIMER3_BASE + TIMER_PCR);
182 evt->event_handler(evt);
186 static struct irqaction tegra_timer_irq = {
188 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH,
189 .handler = tegra_timer_interrupt,
190 .dev_id = &tegra_clockevent,
194 static void __init tegra_init_timer(void)
196 unsigned long rate = clk_measure_input_freq();
199 #ifdef CONFIG_HAVE_ARM_TWD
200 twd_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x600);
205 timer_writel(0x000b, TIMERUS_USEC_CFG);
208 timer_writel(0x000c, TIMERUS_USEC_CFG);
211 timer_writel(0x045f, TIMERUS_USEC_CFG);
214 timer_writel(0x0019, TIMERUS_USEC_CFG);
217 WARN(1, "Unknown clock rate");
220 init_fixed_sched_clock(&cd, tegra_update_sched_clock, 32,
221 1000000, SC_MULT, SC_SHIFT);
223 if (clocksource_register_hz(&tegra_clocksource, 1000000)) {
224 printk(KERN_ERR "Failed to register clocksource\n");
228 ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
230 printk(KERN_ERR "Failed to register timer IRQ: %d\n", ret);
234 clockevents_calc_mult_shift(&tegra_clockevent, 1000000, 5);
235 tegra_clockevent.max_delta_ns =
236 clockevent_delta2ns(0x1fffffff, &tegra_clockevent);
237 tegra_clockevent.min_delta_ns =
238 clockevent_delta2ns(0x1, &tegra_clockevent);
239 tegra_clockevent.cpumask = cpu_all_mask;
240 tegra_clockevent.irq = tegra_timer_irq.irq;
241 clockevents_register_device(&tegra_clockevent);
246 struct sys_timer tegra_timer = {
247 .init = tegra_init_timer,
251 static u32 usec_config;
253 void tegra_timer_suspend(void)
255 usec_config = timer_readl(TIMERUS_USEC_CFG);
258 void tegra_timer_resume(void)
260 timer_writel(usec_config, TIMERUS_USEC_CFG);