Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 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> |
Tim Schmielau | de25968 | 2006-01-08 01:02:05 -0800 | [diff] [blame] | 16 | #include <linux/jiffies.h> |
Catalin Marinas | a8655e8 | 2008-02-04 17:30:57 +0100 | [diff] [blame] | 17 | #include <linux/percpu.h> |
| 18 | #include <linux/clockchips.h> |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 19 | #include <linux/irq.h> |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 20 | |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 21 | #include <asm/hardware/arm_twd.h> |
| 22 | #include <asm/hardware/gic.h> |
Russell King | a09e64f | 2008-08-05 16:14:15 +0100 | [diff] [blame^] | 23 | #include <mach/hardware.h> |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 24 | #include <asm/io.h> |
| 25 | #include <asm/irq.h> |
| 26 | |
Catalin Marinas | a8655e8 | 2008-02-04 17:30:57 +0100 | [diff] [blame] | 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 | |
Catalin Marinas | 39e823e | 2008-02-04 17:45:03 +0100 | [diff] [blame] | 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 | |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 47 | static unsigned long mpcore_timer_rate; |
| 48 | |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 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 | |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 86 | /* |
| 87 | * local_timer_ack: checks for a local timer interrupt. |
| 88 | * |
Simon Arlott | 6cbdc8c | 2007-05-11 20:40:30 +0100 | [diff] [blame] | 89 | * If a local timer interrupt has occurred, acknowledge and return 1. |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 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 | |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 104 | static void __cpuinit twd_calibrate_rate(unsigned int cpu) |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 105 | { |
| 106 | void __iomem *base = TWD_BASE(cpu); |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 107 | unsigned long load, count; |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 108 | u64 waitjiffies; |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 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); |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 146 | } |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 147 | |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 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; |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 155 | |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 156 | twd_calibrate_rate(cpu); |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 157 | |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 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; |
| 164 | clk->cpumask = cpumask_of_cpu(cpu); |
| 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); |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 169 | |
| 170 | /* Make sure our local interrupt controller has this enabled */ |
Catalin Marinas | 93c2904 | 2008-02-04 17:32:57 +0100 | [diff] [blame] | 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); |
Russell King | 2a98beb | 2005-11-09 10:50:29 +0000 | [diff] [blame] | 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 | } |
Catalin Marinas | a8655e8 | 2008-02-04 17:30:57 +0100 | [diff] [blame] | 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; |
| 202 | clk->cpumask = cpumask_of_cpu(cpu); |
| 203 | |
| 204 | clockevents_register_device(clk); |
| 205 | } |
| 206 | |
| 207 | #endif /* !CONFIG_LOCAL_TIMERS */ |