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Diffstat (limited to 'arch/x86/kernel/i8253.c')
-rw-r--r--arch/x86/kernel/i8253.c93
1 files changed, 3 insertions, 90 deletions
diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c
index 5783e6de2079..f2b96de3c7c1 100644
--- a/arch/x86/kernel/i8253.c
+++ b/arch/x86/kernel/i8253.c
@@ -3,15 +3,9 @@
3 * 3 *
4 */ 4 */
5#include <linux/clockchips.h> 5#include <linux/clockchips.h>
6#include <linux/interrupt.h>
7#include <linux/spinlock.h>
8#include <linux/jiffies.h>
9#include <linux/module.h> 6#include <linux/module.h>
10#include <linux/timex.h> 7#include <linux/timex.h>
11#include <linux/delay.h>
12#include <linux/i8253.h> 8#include <linux/i8253.h>
13#include <linux/init.h>
14#include <linux/io.h>
15 9
16#include <asm/hpet.h> 10#include <asm/hpet.h>
17#include <asm/time.h> 11#include <asm/time.h>
@@ -23,91 +17,10 @@
23 */ 17 */
24struct clock_event_device *global_clock_event; 18struct clock_event_device *global_clock_event;
25 19
26/*
27 * Initialize the PIT timer.
28 *
29 * This is also called after resume to bring the PIT into operation again.
30 */
31static void init_pit_timer(enum clock_event_mode mode,
32 struct clock_event_device *evt)
33{
34 raw_spin_lock(&i8253_lock);
35
36 switch (mode) {
37 case CLOCK_EVT_MODE_PERIODIC:
38 /* binary, mode 2, LSB/MSB, ch 0 */
39 outb_pit(0x34, PIT_MODE);
40 outb_pit(LATCH & 0xff , PIT_CH0); /* LSB */
41 outb_pit(LATCH >> 8 , PIT_CH0); /* MSB */
42 break;
43
44 case CLOCK_EVT_MODE_SHUTDOWN:
45 case CLOCK_EVT_MODE_UNUSED:
46 if (evt->mode == CLOCK_EVT_MODE_PERIODIC ||
47 evt->mode == CLOCK_EVT_MODE_ONESHOT) {
48 outb_pit(0x30, PIT_MODE);
49 outb_pit(0, PIT_CH0);
50 outb_pit(0, PIT_CH0);
51 }
52 break;
53
54 case CLOCK_EVT_MODE_ONESHOT:
55 /* One shot setup */
56 outb_pit(0x38, PIT_MODE);
57 break;
58
59 case CLOCK_EVT_MODE_RESUME:
60 /* Nothing to do here */
61 break;
62 }
63 raw_spin_unlock(&i8253_lock);
64}
65
66/*
67 * Program the next event in oneshot mode
68 *
69 * Delta is given in PIT ticks
70 */
71static int pit_next_event(unsigned long delta, struct clock_event_device *evt)
72{
73 raw_spin_lock(&i8253_lock);
74 outb_pit(delta & 0xff , PIT_CH0); /* LSB */
75 outb_pit(delta >> 8 , PIT_CH0); /* MSB */
76 raw_spin_unlock(&i8253_lock);
77
78 return 0;
79}
80
81/*
82 * On UP the PIT can serve all of the possible timer functions. On SMP systems
83 * it can be solely used for the global tick.
84 *
85 * The profiling and update capabilities are switched off once the local apic is
86 * registered. This mechanism replaces the previous #ifdef LOCAL_APIC -
87 * !using_apic_timer decisions in do_timer_interrupt_hook()
88 */
89static struct clock_event_device pit_ce = {
90 .name = "pit",
91 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
92 .set_mode = init_pit_timer,
93 .set_next_event = pit_next_event,
94 .irq = 0,
95};
96
97/*
98 * Initialize the conversion factor and the min/max deltas of the clock event
99 * structure and register the clock event source with the framework.
100 */
101void __init setup_pit_timer(void) 20void __init setup_pit_timer(void)
102{ 21{
103 /* 22 clockevent_i8253_init(true);
104 * Start pit with the boot cpu mask and make it global after the 23 global_clock_event = &i8253_clockevent;
105 * IO_APIC has been initialized.
106 */
107 pit_ce.cpumask = cpumask_of(smp_processor_id());
108
109 clockevents_config_and_register(&pit_ce, CLOCK_TICK_RATE, 0xF, 0x7FFF);
110 global_clock_event = &pit_ce;
111} 24}
112 25
113#ifndef CONFIG_X86_64 26#ifndef CONFIG_X86_64
@@ -121,7 +34,7 @@ static int __init init_pit_clocksource(void)
121 * - when local APIC timer is active (PIT is switched off) 34 * - when local APIC timer is active (PIT is switched off)
122 */ 35 */
123 if (num_possible_cpus() > 1 || is_hpet_enabled() || 36 if (num_possible_cpus() > 1 || is_hpet_enabled() ||
124 pit_ce.mode != CLOCK_EVT_MODE_PERIODIC) 37 i8253_clockevent.mode != CLOCK_EVT_MODE_PERIODIC)
125 return 0; 38 return 0;
126 39
127 return clocksource_i8253_init(); 40 return clocksource_i8253_init();