]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * linux/arch/arm/kernel/smp_twd.c | |
3 | * | |
4 | * Copyright (C) 2002 ARM Ltd. | |
5 | * All Rights Reserved | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | #include <linux/init.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/smp.h> | |
16 | #include <linux/jiffies.h> | |
17 | #include <linux/clockchips.h> | |
18 | #include <linux/irq.h> | |
19 | #include <linux/io.h> | |
20 | ||
21 | #include <asm/smp_twd.h> | |
22 | #include <asm/hardware/gic.h> | |
23 | ||
24 | #define TWD_TIMER_LOAD 0x00 | |
25 | #define TWD_TIMER_COUNTER 0x04 | |
26 | #define TWD_TIMER_CONTROL 0x08 | |
27 | #define TWD_TIMER_INTSTAT 0x0C | |
28 | ||
29 | #define TWD_WDOG_LOAD 0x20 | |
30 | #define TWD_WDOG_COUNTER 0x24 | |
31 | #define TWD_WDOG_CONTROL 0x28 | |
32 | #define TWD_WDOG_INTSTAT 0x2C | |
33 | #define TWD_WDOG_RESETSTAT 0x30 | |
34 | #define TWD_WDOG_DISABLE 0x34 | |
35 | ||
36 | #define TWD_TIMER_CONTROL_ENABLE (1 << 0) | |
37 | #define TWD_TIMER_CONTROL_ONESHOT (0 << 1) | |
38 | #define TWD_TIMER_CONTROL_PERIODIC (1 << 1) | |
39 | #define TWD_TIMER_CONTROL_IT_ENABLE (1 << 2) | |
40 | ||
41 | /* set up by the platform code */ | |
42 | void __iomem *twd_base; | |
43 | ||
44 | static unsigned long twd_timer_rate; | |
45 | ||
46 | static void twd_set_mode(enum clock_event_mode mode, | |
47 | struct clock_event_device *clk) | |
48 | { | |
49 | unsigned long ctrl; | |
50 | ||
51 | switch (mode) { | |
52 | case CLOCK_EVT_MODE_PERIODIC: | |
53 | /* timer load already set up */ | |
54 | ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE | |
55 | | TWD_TIMER_CONTROL_PERIODIC; | |
56 | break; | |
57 | case CLOCK_EVT_MODE_ONESHOT: | |
58 | /* period set, and timer enabled in 'next_event' hook */ | |
59 | ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT; | |
60 | break; | |
61 | case CLOCK_EVT_MODE_UNUSED: | |
62 | case CLOCK_EVT_MODE_SHUTDOWN: | |
63 | default: | |
64 | ctrl = 0; | |
65 | } | |
66 | ||
67 | __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL); | |
68 | } | |
69 | ||
70 | static int twd_set_next_event(unsigned long evt, | |
71 | struct clock_event_device *unused) | |
72 | { | |
73 | unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL); | |
74 | ||
75 | ctrl |= TWD_TIMER_CONTROL_ENABLE; | |
76 | ||
77 | __raw_writel(evt, twd_base + TWD_TIMER_COUNTER); | |
78 | __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | /* | |
84 | * local_timer_ack: checks for a local timer interrupt. | |
85 | * | |
86 | * If a local timer interrupt has occurred, acknowledge and return 1. | |
87 | * Otherwise, return 0. | |
88 | */ | |
89 | int twd_timer_ack(void) | |
90 | { | |
91 | if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) { | |
92 | __raw_writel(1, twd_base + TWD_TIMER_INTSTAT); | |
93 | return 1; | |
94 | } | |
95 | ||
96 | return 0; | |
97 | } | |
98 | ||
99 | static void __cpuinit twd_calibrate_rate(void) | |
100 | { | |
101 | unsigned long load, count; | |
102 | u64 waitjiffies; | |
103 | ||
104 | /* | |
105 | * If this is the first time round, we need to work out how fast | |
106 | * the timer ticks | |
107 | */ | |
108 | if (twd_timer_rate == 0) { | |
109 | printk(KERN_INFO "Calibrating local timer... "); | |
110 | ||
111 | /* Wait for a tick to start */ | |
112 | waitjiffies = get_jiffies_64() + 1; | |
113 | ||
114 | while (get_jiffies_64() < waitjiffies) | |
115 | udelay(10); | |
116 | ||
117 | /* OK, now the tick has started, let's get the timer going */ | |
118 | waitjiffies += 5; | |
119 | ||
120 | /* enable, no interrupt or reload */ | |
121 | __raw_writel(0x1, twd_base + TWD_TIMER_CONTROL); | |
122 | ||
123 | /* maximum value */ | |
124 | __raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER); | |
125 | ||
126 | while (get_jiffies_64() < waitjiffies) | |
127 | udelay(10); | |
128 | ||
129 | count = __raw_readl(twd_base + TWD_TIMER_COUNTER); | |
130 | ||
131 | twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5); | |
132 | ||
133 | printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000, | |
134 | (twd_timer_rate / 100000) % 100); | |
135 | } | |
136 | ||
137 | load = twd_timer_rate / HZ; | |
138 | ||
139 | __raw_writel(load, twd_base + TWD_TIMER_LOAD); | |
140 | } | |
141 | ||
142 | /* | |
143 | * Setup the local clock events for a CPU. | |
144 | */ | |
145 | void __cpuinit twd_timer_setup(struct clock_event_device *clk) | |
146 | { | |
147 | unsigned long flags; | |
148 | ||
149 | twd_calibrate_rate(); | |
150 | ||
151 | clk->name = "local_timer"; | |
152 | clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; | |
153 | clk->rating = 350; | |
154 | clk->set_mode = twd_set_mode; | |
155 | clk->set_next_event = twd_set_next_event; | |
156 | clk->shift = 20; | |
157 | clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift); | |
158 | clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); | |
159 | clk->min_delta_ns = clockevent_delta2ns(0xf, clk); | |
160 | ||
161 | /* Make sure our local interrupt controller has this enabled */ | |
162 | local_irq_save(flags); | |
163 | get_irq_chip(clk->irq)->unmask(clk->irq); | |
164 | local_irq_restore(flags); | |
165 | ||
166 | clockevents_register_device(clk); | |
167 | } | |
168 | ||
169 | /* | |
170 | * take a local timer down | |
171 | */ | |
172 | void __cpuexit twd_timer_stop(void) | |
173 | { | |
174 | __raw_writel(0, twd_base + TWD_TIMER_CONTROL); | |
175 | } |