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comparison source/timer.c @ 0:ed10291ff195

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author mir3636
date Sun, 06 Jan 2019 19:27:03 +0900
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-1:000000000000 0:ed10291ff195
1 /*****************************************************************
2 * timer.c
3 * by Zhiyi Huang, hzy@cs.otago.ac.nz
4 * University of Otago
5 *
6 ********************************************************************/
7
8 // The System Timer peripheral
9
10 #include "types.h"
11 #include "defs.h"
12 #include "param.h"
13 #include "memlayout.h"
14 #include "proc.h"
15 #include "traps.h"
16 #include "arm.h"
17 #include "spinlock.h"
18
19 #define TIMER_REGS_BASE (MMIO_VA+0x003000)
20 #define CONTROL_STATUS 0x0 // control/status
21 #define COUNTER_LO 0x4 // the time-stamp lower 32 bits
22 #define COUNTER_HI 0x8 // the time-stamp higher 32 bits
23 #define COMPARE0 0xc // compare 0
24 #define COMPARE1 0x10 // compare 1
25 #define COMPARE2 0x14 // compare 2
26 #define COMPARE3 0x18 // compare 3
27
28 #define TIMER_FREQ 10000 // interrupt 100 times/sec.
29
30 void
31 enabletimer3irq(void)
32 {
33 intctrlregs *ip;
34
35 ip = (intctrlregs *)INT_REGS_BASE;
36 ip->gpuenable[0] |= 1 << IRQ_TIMER3; // enable the system timer3 irq
37 }
38
39
40 void
41 timer3init(void)
42 {
43 uint v;
44
45 enabletimer3irq();
46
47 v = inw(TIMER_REGS_BASE+COUNTER_LO);
48 v += TIMER_FREQ;
49
50 outw(TIMER_REGS_BASE+COMPARE3, v);
51 ticks = 0;
52 }
53
54 void
55 timer3intr(void)
56 {
57 uint v;
58 //cprintf("timer3 interrupt: %x\n", inw(TIMER_REGS_BASE+CONTROL_STATUS));
59 outw(TIMER_REGS_BASE+CONTROL_STATUS, (1 << IRQ_TIMER3)); // clear timer3 irq
60
61 ticks++;
62 wakeup(&ticks);
63
64 // reset the value of compare3
65 v=inw(TIMER_REGS_BASE+COUNTER_LO);
66 v += TIMER_FREQ;
67 outw(TIMER_REGS_BASE+COMPARE3, v);
68 }
69
70 void
71 delay(uint m)
72 {
73 unsigned long long t;
74
75 if(m == 0) return;
76
77 t = getsystemtime() + m;
78 while(t != getsystemtime());
79
80 return;
81 }