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timers.c
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1 /***************************************************************************/
2 
3 /*
4  * linux/arch/m68knommu/platform/68328/timers.c
5  *
6  * Copyright (C) 1993 Hamish Macdonald
7  * Copyright (C) 1999 D. Jeff Dionne
8  * Copyright (C) 2001 Georges Menie, Ken Desmet
9  *
10  * This file is subject to the terms and conditions of the GNU General Public
11  * License. See the file COPYING in the main directory of this archive
12  * for more details.
13  */
14 
15 /***************************************************************************/
16 
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/mm.h>
20 #include <linux/interrupt.h>
21 #include <linux/irq.h>
22 #include <linux/clocksource.h>
23 #include <linux/rtc.h>
24 #include <asm/setup.h>
25 #include <asm/pgtable.h>
26 #include <asm/machdep.h>
27 #include <asm/MC68VZ328.h>
28 
29 /***************************************************************************/
30 
31 #if defined(CONFIG_DRAGEN2)
32 /* with a 33.16 MHz clock, this will give usec resolution to the time functions */
33 #define CLOCK_SOURCE TCTL_CLKSOURCE_SYSCLK
34 #define CLOCK_PRE 7
35 #define TICKS_PER_JIFFY 41450
36 
37 #elif defined(CONFIG_XCOPILOT_BUGS)
38 /*
39  * The only thing I know is that CLK32 is not available on Xcopilot
40  * I have little idea about what frequency SYSCLK has on Xcopilot.
41  * The values for prescaler and compare registers were simply
42  * taken from the original source
43  */
44 #define CLOCK_SOURCE TCTL_CLKSOURCE_SYSCLK
45 #define CLOCK_PRE 2
46 #define TICKS_PER_JIFFY 0xd7e4
47 
48 #else
49 /* default to using the 32Khz clock */
50 #define CLOCK_SOURCE TCTL_CLKSOURCE_32KHZ
51 #define CLOCK_PRE 31
52 #define TICKS_PER_JIFFY 10
53 #endif
54 
55 static u32 m68328_tick_cnt;
56 static irq_handler_t timer_interrupt;
57 
58 /***************************************************************************/
59 
60 static irqreturn_t hw_tick(int irq, void *dummy)
61 {
62  /* Reset Timer1 */
63  TSTAT &= 0;
64 
65  m68328_tick_cnt += TICKS_PER_JIFFY;
66  return timer_interrupt(irq, dummy);
67 }
68 
69 /***************************************************************************/
70 
71 static struct irqaction m68328_timer_irq = {
72  .name = "timer",
73  .flags = IRQF_DISABLED | IRQF_TIMER,
74  .handler = hw_tick,
75 };
76 
77 /***************************************************************************/
78 
79 static cycle_t m68328_read_clk(struct clocksource *cs)
80 {
81  unsigned long flags;
82  u32 cycles;
83 
84  local_irq_save(flags);
85  cycles = m68328_tick_cnt + TCN;
86  local_irq_restore(flags);
87 
88  return cycles;
89 }
90 
91 /***************************************************************************/
92 
93 static struct clocksource m68328_clk = {
94  .name = "timer",
95  .rating = 250,
96  .read = m68328_read_clk,
97  .mask = CLOCKSOURCE_MASK(32),
98  .flags = CLOCK_SOURCE_IS_CONTINUOUS,
99 };
100 
101 /***************************************************************************/
102 
103 void hw_timer_init(irq_handler_t handler)
104 {
105  /* disable timer 1 */
106  TCTL = 0;
107 
108  /* set ISR */
109  setup_irq(TMR_IRQ_NUM, &m68328_timer_irq);
110 
111  /* Restart mode, Enable int, Set clock source */
112  TCTL = TCTL_OM | TCTL_IRQEN | CLOCK_SOURCE;
113  TPRER = CLOCK_PRE;
114  TCMP = TICKS_PER_JIFFY;
115 
116  /* Enable timer 1 */
117  TCTL |= TCTL_TEN;
118  clocksource_register_hz(&m68328_clk, TICKS_PER_JIFFY*HZ);
119  timer_interrupt = handler;
120 }
121 
122 /***************************************************************************/
123 
124 int m68328_hwclk(int set, struct rtc_time *t)
125 {
126  if (!set) {
127  long now = RTCTIME;
128  t->tm_year = t->tm_mon = t->tm_mday = 1;
129  t->tm_hour = (now >> 24) % 24;
130  t->tm_min = (now >> 16) % 60;
131  t->tm_sec = now % 60;
132  }
133 
134  return 0;
135 }
136 
137 /***************************************************************************/
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