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2a98beb6 RK |
1 | /* |
2 | * linux/arch/arm/mach-realview/localtimer.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> | |
de25968c | 16 | #include <linux/jiffies.h> |
a8655e83 CM |
17 | #include <linux/percpu.h> |
18 | #include <linux/clockchips.h> | |
93c2904d | 19 | #include <linux/irq.h> |
fced80c7 | 20 | #include <linux/io.h> |
2a98beb6 | 21 | |
2a98beb6 RK |
22 | #include <asm/hardware/arm_twd.h> |
23 | #include <asm/hardware/gic.h> | |
a09e64fb | 24 | #include <mach/hardware.h> |
2a98beb6 RK |
25 | #include <asm/irq.h> |
26 | ||
a8655e83 CM |
27 | static DEFINE_PER_CPU(struct clock_event_device, local_clockevent); |
28 | ||
29 | /* | |
30 | * Used on SMP for either the local timer or IPI_TIMER | |
31 | */ | |
32 | void local_timer_interrupt(void) | |
33 | { | |
34 | struct clock_event_device *clk = &__get_cpu_var(local_clockevent); | |
35 | ||
36 | clk->event_handler(clk); | |
37 | } | |
38 | ||
39 | #ifdef CONFIG_LOCAL_TIMERS | |
40 | ||
39e823e3 CM |
41 | #define TWD_BASE(cpu) (twd_base_addr + (cpu) * twd_size) |
42 | ||
43 | /* set up by the platform code */ | |
44 | void __iomem *twd_base_addr; | |
45 | unsigned int twd_size; | |
46 | ||
2a98beb6 RK |
47 | static unsigned long mpcore_timer_rate; |
48 | ||
93c2904d CM |
49 | static void local_timer_set_mode(enum clock_event_mode mode, |
50 | struct clock_event_device *clk) | |
51 | { | |
52 | void __iomem *base = TWD_BASE(smp_processor_id()); | |
53 | unsigned long ctrl; | |
54 | ||
55 | switch(mode) { | |
56 | case CLOCK_EVT_MODE_PERIODIC: | |
57 | /* timer load already set up */ | |
58 | ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE | |
59 | | TWD_TIMER_CONTROL_PERIODIC; | |
60 | break; | |
61 | case CLOCK_EVT_MODE_ONESHOT: | |
62 | /* period set, and timer enabled in 'next_event' hook */ | |
63 | ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT; | |
64 | break; | |
65 | case CLOCK_EVT_MODE_UNUSED: | |
66 | case CLOCK_EVT_MODE_SHUTDOWN: | |
67 | default: | |
68 | ctrl = 0; | |
69 | } | |
70 | ||
71 | __raw_writel(ctrl, base + TWD_TIMER_CONTROL); | |
72 | } | |
73 | ||
74 | static int local_timer_set_next_event(unsigned long evt, | |
75 | struct clock_event_device *unused) | |
76 | { | |
77 | void __iomem *base = TWD_BASE(smp_processor_id()); | |
78 | unsigned long ctrl = __raw_readl(base + TWD_TIMER_CONTROL); | |
79 | ||
80 | __raw_writel(evt, base + TWD_TIMER_COUNTER); | |
81 | __raw_writel(ctrl | TWD_TIMER_CONTROL_ENABLE, base + TWD_TIMER_CONTROL); | |
82 | ||
83 | return 0; | |
84 | } | |
85 | ||
2a98beb6 RK |
86 | /* |
87 | * local_timer_ack: checks for a local timer interrupt. | |
88 | * | |
6cbdc8c5 | 89 | * If a local timer interrupt has occurred, acknowledge and return 1. |
2a98beb6 RK |
90 | * Otherwise, return 0. |
91 | */ | |
92 | int local_timer_ack(void) | |
93 | { | |
94 | void __iomem *base = TWD_BASE(smp_processor_id()); | |
95 | ||
96 | if (__raw_readl(base + TWD_TIMER_INTSTAT)) { | |
97 | __raw_writel(1, base + TWD_TIMER_INTSTAT); | |
98 | return 1; | |
99 | } | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
93c2904d | 104 | static void __cpuinit twd_calibrate_rate(unsigned int cpu) |
2a98beb6 RK |
105 | { |
106 | void __iomem *base = TWD_BASE(cpu); | |
93c2904d | 107 | unsigned long load, count; |
2a98beb6 | 108 | u64 waitjiffies; |
2a98beb6 RK |
109 | |
110 | /* | |
111 | * If this is the first time round, we need to work out how fast | |
112 | * the timer ticks | |
113 | */ | |
114 | if (mpcore_timer_rate == 0) { | |
115 | printk("Calibrating local timer... "); | |
116 | ||
117 | /* Wait for a tick to start */ | |
118 | waitjiffies = get_jiffies_64() + 1; | |
119 | ||
120 | while (get_jiffies_64() < waitjiffies) | |
121 | udelay(10); | |
122 | ||
123 | /* OK, now the tick has started, let's get the timer going */ | |
124 | waitjiffies += 5; | |
125 | ||
126 | /* enable, no interrupt or reload */ | |
127 | __raw_writel(0x1, base + TWD_TIMER_CONTROL); | |
128 | ||
129 | /* maximum value */ | |
130 | __raw_writel(0xFFFFFFFFU, base + TWD_TIMER_COUNTER); | |
131 | ||
132 | while (get_jiffies_64() < waitjiffies) | |
133 | udelay(10); | |
134 | ||
135 | count = __raw_readl(base + TWD_TIMER_COUNTER); | |
136 | ||
137 | mpcore_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5); | |
138 | ||
139 | printk("%lu.%02luMHz.\n", mpcore_timer_rate / 1000000, | |
140 | (mpcore_timer_rate / 100000) % 100); | |
141 | } | |
142 | ||
143 | load = mpcore_timer_rate / HZ; | |
144 | ||
145 | __raw_writel(load, base + TWD_TIMER_LOAD); | |
93c2904d | 146 | } |
2a98beb6 | 147 | |
93c2904d CM |
148 | /* |
149 | * Setup the local clock events for a CPU. | |
150 | */ | |
151 | void __cpuinit local_timer_setup(unsigned int cpu) | |
152 | { | |
153 | struct clock_event_device *clk = &per_cpu(local_clockevent, cpu); | |
154 | unsigned long flags; | |
2a98beb6 | 155 | |
93c2904d | 156 | twd_calibrate_rate(cpu); |
2a98beb6 | 157 | |
93c2904d CM |
158 | clk->name = "local_timer"; |
159 | clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; | |
160 | clk->rating = 350; | |
161 | clk->set_mode = local_timer_set_mode; | |
162 | clk->set_next_event = local_timer_set_next_event; | |
163 | clk->irq = IRQ_LOCALTIMER; | |
320ab2b0 | 164 | clk->cpumask = cpumask_of(cpu); |
93c2904d CM |
165 | clk->shift = 20; |
166 | clk->mult = div_sc(mpcore_timer_rate, NSEC_PER_SEC, clk->shift); | |
167 | clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); | |
168 | clk->min_delta_ns = clockevent_delta2ns(0xf, clk); | |
2a98beb6 RK |
169 | |
170 | /* Make sure our local interrupt controller has this enabled */ | |
93c2904d CM |
171 | local_irq_save(flags); |
172 | get_irq_chip(IRQ_LOCALTIMER)->unmask(IRQ_LOCALTIMER); | |
173 | local_irq_restore(flags); | |
174 | ||
175 | clockevents_register_device(clk); | |
2a98beb6 RK |
176 | } |
177 | ||
178 | /* | |
179 | * take a local timer down | |
180 | */ | |
181 | void __cpuexit local_timer_stop(unsigned int cpu) | |
182 | { | |
183 | __raw_writel(0, TWD_BASE(cpu) + TWD_TIMER_CONTROL); | |
184 | } | |
a8655e83 CM |
185 | |
186 | #else /* CONFIG_LOCAL_TIMERS */ | |
187 | ||
188 | static void dummy_timer_set_mode(enum clock_event_mode mode, | |
189 | struct clock_event_device *clk) | |
190 | { | |
191 | } | |
192 | ||
193 | void __cpuinit local_timer_setup(unsigned int cpu) | |
194 | { | |
195 | struct clock_event_device *clk = &per_cpu(local_clockevent, cpu); | |
196 | ||
197 | clk->name = "dummy_timer"; | |
198 | clk->features = CLOCK_EVT_FEAT_DUMMY; | |
199 | clk->rating = 200; | |
200 | clk->set_mode = dummy_timer_set_mode; | |
201 | clk->broadcast = smp_timer_broadcast; | |
320ab2b0 | 202 | clk->cpumask = cpumask_of(cpu); |
a8655e83 CM |
203 | |
204 | clockevents_register_device(clk); | |
205 | } | |
206 | ||
207 | #endif /* !CONFIG_LOCAL_TIMERS */ |