Pull battery into release branch
[linux-2.6] / arch / arm / plat-iop / time.c
1 /*
2  * arch/arm/plat-iop/time.c
3  *
4  * Timer code for IOP32x and IOP33x based systems
5  *
6  * Author: Deepak Saxena <dsaxena@mvista.com>
7  *
8  * Copyright 2002-2003 MontaVista Software Inc.
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 #include <asm/hardware.h>
22 #include <asm/io.h>
23 #include <asm/irq.h>
24 #include <asm/uaccess.h>
25 #include <asm/mach/irq.h>
26 #include <asm/mach/time.h>
27 #include <asm/arch/time.h>
28
29 static unsigned long ticks_per_jiffy;
30 static unsigned long ticks_per_usec;
31 static unsigned long next_jiffy_time;
32
33 unsigned long iop_gettimeoffset(void)
34 {
35         unsigned long offset, temp;
36
37         /* enable cp6, if necessary, to avoid taking the overhead of an
38          * undefined instruction trap
39          */
40         asm volatile (
41         "mrc    p15, 0, %0, c15, c1, 0\n\t"
42         "tst    %0, #(1 << 6)\n\t"
43         "orreq  %0, %0, #(1 << 6)\n\t"
44         "mcreq  p15, 0, %0, c15, c1, 0\n\t"
45 #ifdef CONFIG_CPU_XSCALE
46         "mrceq  p15, 0, %0, c15, c1, 0\n\t"
47         "moveq  %0, %0\n\t"
48         "subeq  pc, pc, #4\n\t"
49 #endif
50         : "=r"(temp) : : "cc");
51
52         offset = next_jiffy_time - read_tcr1();
53
54         return offset / ticks_per_usec;
55 }
56
57 static irqreturn_t
58 iop_timer_interrupt(int irq, void *dev_id)
59 {
60         write_seqlock(&xtime_lock);
61
62         write_tisr(1);
63
64         while ((signed long)(next_jiffy_time - read_tcr1())
65                 >= ticks_per_jiffy) {
66                 timer_tick();
67                 next_jiffy_time -= ticks_per_jiffy;
68         }
69
70         write_sequnlock(&xtime_lock);
71
72         return IRQ_HANDLED;
73 }
74
75 static struct irqaction iop_timer_irq = {
76         .name           = "IOP Timer Tick",
77         .handler        = iop_timer_interrupt,
78         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
79 };
80
81 void __init iop_init_time(unsigned long tick_rate)
82 {
83         u32 timer_ctl;
84
85         ticks_per_jiffy = (tick_rate + HZ/2) / HZ;
86         ticks_per_usec = tick_rate / 1000000;
87         next_jiffy_time = 0xffffffff;
88
89         timer_ctl = IOP_TMR_EN | IOP_TMR_PRIVILEGED |
90                         IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1;
91
92         /*
93          * We use timer 0 for our timer interrupt, and timer 1 as
94          * monotonic counter for tracking missed jiffies.
95          */
96         write_trr0(ticks_per_jiffy - 1);
97         write_tmr0(timer_ctl);
98         write_trr1(0xffffffff);
99         write_tmr1(timer_ctl);
100
101         setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
102 }