Merge branch 'cow_readahead' of git://oss.oracle.com/git/tma/linux-2.6 into merge-2
[deliverable/linux.git] / arch / arm / mach-tegra / timer.c
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1/*
2 * arch/arch/mach-tegra/timer.c
3 *
4 * Copyright (C) 2010 Google, Inc.
5 *
6 * Author:
7 * Colin Cross <ccross@google.com>
8 *
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.
12 *
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.
17 *
18 */
19
20#include <linux/init.h>
21#include <linux/time.h>
22#include <linux/interrupt.h>
23#include <linux/irq.h>
24#include <linux/clockchips.h>
25#include <linux/clocksource.h>
26#include <linux/clk.h>
27#include <linux/io.h>
28#include <linux/cnt32_to_63.h>
29
30#include <asm/mach/time.h>
31#include <asm/mach/time.h>
32#include <asm/localtimer.h>
33
34#include <mach/iomap.h>
35#include <mach/irqs.h>
36
37#include "board.h"
38#include "clock.h"
39
40#define TIMERUS_CNTR_1US 0x10
41#define TIMERUS_USEC_CFG 0x14
42#define TIMERUS_CNTR_FREEZE 0x4c
43
44#define TIMER1_BASE 0x0
45#define TIMER2_BASE 0x8
46#define TIMER3_BASE 0x50
47#define TIMER4_BASE 0x58
48
49#define TIMER_PTV 0x0
50#define TIMER_PCR 0x4
51
52struct tegra_timer;
53
54static void __iomem *timer_reg_base = IO_ADDRESS(TEGRA_TMR1_BASE);
55
56#define timer_writel(value, reg) \
57 __raw_writel(value, (u32)timer_reg_base + (reg))
58#define timer_readl(reg) \
59 __raw_readl((u32)timer_reg_base + (reg))
60
61static int tegra_timer_set_next_event(unsigned long cycles,
62 struct clock_event_device *evt)
63{
64 u32 reg;
65
66 reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
67 timer_writel(reg, TIMER3_BASE + TIMER_PTV);
68
69 return 0;
70}
71
72static void tegra_timer_set_mode(enum clock_event_mode mode,
73 struct clock_event_device *evt)
74{
75 u32 reg;
76
77 timer_writel(0, TIMER3_BASE + TIMER_PTV);
78
79 switch (mode) {
80 case CLOCK_EVT_MODE_PERIODIC:
81 reg = 0xC0000000 | ((1000000/HZ)-1);
82 timer_writel(reg, TIMER3_BASE + TIMER_PTV);
83 break;
84 case CLOCK_EVT_MODE_ONESHOT:
85 break;
86 case CLOCK_EVT_MODE_UNUSED:
87 case CLOCK_EVT_MODE_SHUTDOWN:
88 case CLOCK_EVT_MODE_RESUME:
89 break;
90 }
91}
92
93static cycle_t tegra_clocksource_read(struct clocksource *cs)
94{
95 return cnt32_to_63(timer_readl(TIMERUS_CNTR_1US));
96}
97
98static struct clock_event_device tegra_clockevent = {
99 .name = "timer0",
100 .rating = 300,
101 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
102 .set_next_event = tegra_timer_set_next_event,
103 .set_mode = tegra_timer_set_mode,
104};
105
106static struct clocksource tegra_clocksource = {
107 .name = "timer_us",
108 .rating = 300,
109 .read = tegra_clocksource_read,
110 .mask = 0x7FFFFFFFFFFFFFFFULL,
111 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
112};
113
114unsigned long long sched_clock(void)
115{
116 return clocksource_cyc2ns(tegra_clocksource.read(&tegra_clocksource),
117 tegra_clocksource.mult, tegra_clocksource.shift);
118}
119
120static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
121{
122 struct clock_event_device *evt = (struct clock_event_device *)dev_id;
123 timer_writel(1<<30, TIMER3_BASE + TIMER_PCR);
124 evt->event_handler(evt);
125 return IRQ_HANDLED;
126}
127
128static struct irqaction tegra_timer_irq = {
129 .name = "timer0",
130 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH,
131 .handler = tegra_timer_interrupt,
132 .dev_id = &tegra_clockevent,
133 .irq = INT_TMR3,
134};
135
136static void __init tegra_init_timer(void)
137{
138 unsigned long rate = clk_measure_input_freq();
139 int ret;
140
141#ifdef CONFIG_HAVE_ARM_TWD
142 twd_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x600);
143#endif
144
145 switch (rate) {
146 case 12000000:
147 timer_writel(0x000b, TIMERUS_USEC_CFG);
148 break;
149 case 13000000:
150 timer_writel(0x000c, TIMERUS_USEC_CFG);
151 break;
152 case 19200000:
153 timer_writel(0x045f, TIMERUS_USEC_CFG);
154 break;
155 case 26000000:
156 timer_writel(0x0019, TIMERUS_USEC_CFG);
157 break;
158 default:
159 WARN(1, "Unknown clock rate");
160 }
161
162 if (clocksource_register_hz(&tegra_clocksource, 1000000)) {
163 printk(KERN_ERR "Failed to register clocksource\n");
164 BUG();
165 }
166
167 ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
168 if (ret) {
169 printk(KERN_ERR "Failed to register timer IRQ: %d\n", ret);
170 BUG();
171 }
172
173 clockevents_calc_mult_shift(&tegra_clockevent, 1000000, 5);
174 tegra_clockevent.max_delta_ns =
175 clockevent_delta2ns(0x1fffffff, &tegra_clockevent);
176 tegra_clockevent.min_delta_ns =
177 clockevent_delta2ns(0x1, &tegra_clockevent);
178 tegra_clockevent.cpumask = cpu_all_mask;
179 tegra_clockevent.irq = tegra_timer_irq.irq;
180 clockevents_register_device(&tegra_clockevent);
181
182 return;
183}
184
185struct sys_timer tegra_timer = {
186 .init = tegra_init_timer,
187};
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