Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 1 | /* |
| 2 | * This file is subject to the terms and conditions of the GNU General Public |
| 3 | * License. See the file "COPYING" in the main directory of this archive |
| 4 | * for more details. |
| 5 | * |
| 6 | * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. |
| 7 | */ |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 8 | #include <linux/clockchips.h> |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 9 | #include <linux/cpu.h> |
Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 10 | #include <linux/init.h> |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 11 | #include <linux/interrupt.h> |
Andrew Bresticker | 4060bbe | 2014-10-20 12:03:53 -0700 | [diff] [blame] | 12 | #include <linux/irqchip/mips-gic.h> |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 13 | #include <linux/notifier.h> |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 14 | #include <linux/percpu.h> |
| 15 | #include <linux/smp.h> |
Steven J. Hill | dfa762e | 2013-04-10 16:28:36 -0500 | [diff] [blame] | 16 | #include <linux/time.h> |
Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 17 | |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 18 | #include <asm/time.h> |
| 19 | |
Andrew Bresticker | 5fee56e | 2014-10-20 12:04:00 -0700 | [diff] [blame] | 20 | static DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device); |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 21 | static int gic_timer_irq; |
Andrew Bresticker | b085451 | 2014-10-20 12:04:01 -0700 | [diff] [blame] | 22 | static unsigned int gic_frequency; |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 23 | |
| 24 | static int gic_next_event(unsigned long delta, struct clock_event_device *evt) |
| 25 | { |
| 26 | u64 cnt; |
| 27 | int res; |
| 28 | |
| 29 | cnt = gic_read_count(); |
| 30 | cnt += (u64)delta; |
| 31 | gic_write_cpu_compare(cnt, cpumask_first(evt->cpumask)); |
| 32 | res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0; |
| 33 | return res; |
| 34 | } |
| 35 | |
Andrew Bresticker | 5fee56e | 2014-10-20 12:04:00 -0700 | [diff] [blame] | 36 | static void gic_set_clock_mode(enum clock_event_mode mode, |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 37 | struct clock_event_device *evt) |
| 38 | { |
| 39 | /* Nothing to do ... */ |
| 40 | } |
| 41 | |
Andrew Bresticker | 5fee56e | 2014-10-20 12:04:00 -0700 | [diff] [blame] | 42 | static irqreturn_t gic_compare_interrupt(int irq, void *dev_id) |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 43 | { |
Andrew Bresticker | f7ea306 | 2014-10-20 12:04:03 -0700 | [diff] [blame] | 44 | struct clock_event_device *cd = dev_id; |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 45 | |
| 46 | gic_write_compare(gic_read_compare()); |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 47 | cd->event_handler(cd); |
| 48 | return IRQ_HANDLED; |
| 49 | } |
| 50 | |
| 51 | struct irqaction gic_compare_irqaction = { |
| 52 | .handler = gic_compare_interrupt, |
Andrew Bresticker | f7ea306 | 2014-10-20 12:04:03 -0700 | [diff] [blame] | 53 | .percpu_dev_id = &gic_clockevent_device, |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 54 | .flags = IRQF_PERCPU | IRQF_TIMER, |
| 55 | .name = "timer", |
| 56 | }; |
| 57 | |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 58 | static void gic_clockevent_cpu_init(struct clock_event_device *cd) |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 59 | { |
| 60 | unsigned int cpu = smp_processor_id(); |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 61 | |
| 62 | cd->name = "MIPS GIC"; |
| 63 | cd->features = CLOCK_EVT_FEAT_ONESHOT | |
| 64 | CLOCK_EVT_FEAT_C3STOP; |
| 65 | |
| 66 | clockevent_set_clock(cd, gic_frequency); |
| 67 | |
| 68 | /* Calculate the min / max delta */ |
| 69 | cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd); |
| 70 | cd->min_delta_ns = clockevent_delta2ns(0x300, cd); |
| 71 | |
| 72 | cd->rating = 300; |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 73 | cd->irq = gic_timer_irq; |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 74 | cd->cpumask = cpumask_of(cpu); |
| 75 | cd->set_next_event = gic_next_event; |
| 76 | cd->set_mode = gic_set_clock_mode; |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 77 | |
| 78 | clockevents_register_device(cd); |
| 79 | |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 80 | enable_percpu_irq(gic_timer_irq, IRQ_TYPE_NONE); |
| 81 | } |
| 82 | |
| 83 | static void gic_clockevent_cpu_exit(struct clock_event_device *cd) |
| 84 | { |
| 85 | disable_percpu_irq(gic_timer_irq); |
| 86 | } |
| 87 | |
| 88 | static int gic_cpu_notifier(struct notifier_block *nb, unsigned long action, |
| 89 | void *data) |
| 90 | { |
| 91 | switch (action & ~CPU_TASKS_FROZEN) { |
| 92 | case CPU_STARTING: |
| 93 | gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device)); |
| 94 | break; |
| 95 | case CPU_DYING: |
| 96 | gic_clockevent_cpu_exit(this_cpu_ptr(&gic_clockevent_device)); |
| 97 | break; |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 98 | } |
| 99 | |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 100 | return NOTIFY_OK; |
| 101 | } |
| 102 | |
| 103 | static struct notifier_block gic_cpu_nb = { |
| 104 | .notifier_call = gic_cpu_notifier, |
| 105 | }; |
| 106 | |
| 107 | static int gic_clockevent_init(void) |
| 108 | { |
| 109 | if (!cpu_has_counter || !gic_frequency) |
| 110 | return -ENXIO; |
| 111 | |
| 112 | gic_timer_irq = MIPS_GIC_IRQ_BASE + |
| 113 | GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_COMPARE); |
| 114 | setup_percpu_irq(gic_timer_irq, &gic_compare_irqaction); |
| 115 | |
| 116 | register_cpu_notifier(&gic_cpu_nb); |
| 117 | |
| 118 | gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device)); |
Andrew Bresticker | a331ce6 | 2014-10-20 12:03:59 -0700 | [diff] [blame] | 119 | |
| 120 | return 0; |
| 121 | } |
| 122 | |
Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 123 | static cycle_t gic_hpt_read(struct clocksource *cs) |
| 124 | { |
Steven J. Hill | dfa762e | 2013-04-10 16:28:36 -0500 | [diff] [blame] | 125 | return gic_read_count(); |
Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 126 | } |
| 127 | |
| 128 | static struct clocksource gic_clocksource = { |
| 129 | .name = "GIC", |
| 130 | .read = gic_hpt_read, |
| 131 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| 132 | }; |
| 133 | |
| 134 | void __init gic_clocksource_init(unsigned int frequency) |
| 135 | { |
Andrew Bresticker | b085451 | 2014-10-20 12:04:01 -0700 | [diff] [blame] | 136 | gic_frequency = frequency; |
| 137 | |
Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 138 | /* Set clocksource mask. */ |
Andrew Bresticker | 387904f | 2014-10-20 12:03:49 -0700 | [diff] [blame] | 139 | gic_clocksource.mask = CLOCKSOURCE_MASK(gic_get_count_width()); |
Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 140 | |
| 141 | /* Calculate a somewhat reasonable rating value. */ |
| 142 | gic_clocksource.rating = 200 + frequency / 10000000; |
| 143 | |
| 144 | clocksource_register_hz(&gic_clocksource, frequency); |
Andrew Bresticker | e4752db | 2014-10-20 12:04:04 -0700 | [diff] [blame^] | 145 | |
| 146 | gic_clockevent_init(); |
Steven J. Hill | 778eeb1 | 2012-12-07 03:51:04 +0000 | [diff] [blame] | 147 | } |