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-rw-r--r--arch/arm/mach-iop3xx/iop331-time.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/arm/mach-iop3xx/iop331-time.c b/arch/arm/mach-iop3xx/iop331-time.c
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1/*
2 * arch/arm/mach-iop3xx/iop331-time.c
3 *
4 * Timer code for IOP331 based systems
5 *
6 * Author: Dave Jiang <dave.jiang@intel.com>
7 *
8 * Copyright 2003 Intel Corp.
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 */
15
16#include <linux/kernel.h>
17#include <linux/interrupt.h>
18#include <linux/time.h>
19#include <linux/init.h>
20#include <linux/timex.h>
21
22#include <asm/hardware.h>
23#include <asm/io.h>
24#include <asm/irq.h>
25#include <asm/uaccess.h>
26#include <asm/mach-types.h>
27#include <asm/mach/irq.h>
28#include <asm/mach/time.h>
29
30static inline unsigned long get_elapsed(void)
31{
32 return LATCH - *IOP331_TU_TCR0;
33}
34
35static unsigned long iop331_gettimeoffset(void)
36{
37 unsigned long elapsed, usec;
38 u32 tisr1, tisr2;
39
40 /*
41 * If an interrupt was pending before we read the timer,
42 * we've already wrapped. Factor this into the time.
43 * If an interrupt was pending after we read the timer,
44 * it may have wrapped between checking the interrupt
45 * status and reading the timer. Re-read the timer to
46 * be sure its value is after the wrap.
47 */
48
49 asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr1));
50 elapsed = get_elapsed();
51 asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr2));
52
53 if(tisr1 & 1)
54 elapsed += LATCH;
55 else if (tisr2 & 1)
56 elapsed = LATCH + get_elapsed();
57
58 /*
59 * Now convert them to usec.
60 */
61 usec = (unsigned long)(elapsed * (tick_nsec / 1000)) / LATCH;
62
63 return usec;
64}
65
66static irqreturn_t
67iop331_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
68{
69 u32 tisr;
70
71 write_seqlock(&xtime_lock);
72
73 asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr));
74 tisr |= 1;
75 asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (tisr));
76
77 timer_tick(regs);
78
79 write_sequnlock(&xtime_lock);
80 return IRQ_HANDLED;
81}
82
83static struct irqaction iop331_timer_irq = {
84 .name = "IOP331 Timer Tick",
85 .handler = iop331_timer_interrupt,
86 .flags = SA_INTERRUPT
87};
88
89static void __init iop331_timer_init(void)
90{
91 u32 timer_ctl;
92
93 setup_irq(IRQ_IOP331_TIMER0, &iop331_timer_irq);
94
95 timer_ctl = IOP331_TMR_EN | IOP331_TMR_PRIVILEGED | IOP331_TMR_RELOAD |
96 IOP331_TMR_RATIO_1_1;
97
98 asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (LATCH));
99
100 asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl));
101
102}
103
104struct sys_timer iop331_timer = {
105 .init = iop331_timer_init,
106 .offset = iop331_gettimeoffset,
107};