1/***************************************************************************/
2
3/*
4 * timers.c - Generic hardware timer support.
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/machdep.h>
26#include <asm/MC68VZ328.h>
27
28#include "m68328.h"
29
30/***************************************************************************/
31
32#if defined(CONFIG_DRAGEN2)
33/* with a 33.16 MHz clock, this will give usec resolution to the time functions */
34#define CLOCK_SOURCE TCTL_CLKSOURCE_SYSCLK
35#define CLOCK_PRE 7
36#define TICKS_PER_JIFFY 41450
37
38#elif defined(CONFIG_XCOPILOT_BUGS)
39/*
40 * The only thing I know is that CLK32 is not available on Xcopilot
41 * I have little idea about what frequency SYSCLK has on Xcopilot.
42 * The values for prescaler and compare registers were simply
43 * taken from the original source
44 */
45#define CLOCK_SOURCE TCTL_CLKSOURCE_SYSCLK
46#define CLOCK_PRE 2
47#define TICKS_PER_JIFFY 0xd7e4
48
49#else
50/* default to using the 32Khz clock */
51#define CLOCK_SOURCE TCTL_CLKSOURCE_32KHZ
52#define CLOCK_PRE 31
53#define TICKS_PER_JIFFY 10
54#endif
55
56static u32 m68328_tick_cnt;
57
58/***************************************************************************/
59
60static irqreturn_t hw_tick(int irq, void *dummy)
61{
62 /* Reset Timer1 */
63 TSTAT &= 0;
64
65 m68328_tick_cnt += TICKS_PER_JIFFY;
66 legacy_timer_tick(ticks: 1);
67 return IRQ_HANDLED;
68}
69
70/***************************************************************************/
71
72static u64 m68328_read_clk(struct clocksource *cs)
73{
74 unsigned long flags;
75 u32 cycles;
76
77 local_irq_save(flags);
78 cycles = m68328_tick_cnt + TCN;
79 local_irq_restore(flags);
80
81 return cycles;
82}
83
84/***************************************************************************/
85
86static struct clocksource m68328_clk = {
87 .name = "timer",
88 .rating = 250,
89 .read = m68328_read_clk,
90 .mask = CLOCKSOURCE_MASK(32),
91 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
92};
93
94/***************************************************************************/
95
96void hw_timer_init(void)
97{
98 int ret;
99
100 /* disable timer 1 */
101 TCTL = 0;
102
103 /* set ISR */
104 ret = request_irq(irq: TMR_IRQ_NUM, handler: hw_tick, IRQF_TIMER, name: "timer", NULL);
105 if (ret) {
106 pr_err("Failed to request irq %d (timer): %pe\n", TMR_IRQ_NUM,
107 ERR_PTR(ret));
108 }
109
110 /* Restart mode, Enable int, Set clock source */
111 TCTL = TCTL_OM | TCTL_IRQEN | CLOCK_SOURCE;
112 TPRER = CLOCK_PRE;
113 TCMP = TICKS_PER_JIFFY;
114
115 /* Enable timer 1 */
116 TCTL |= TCTL_TEN;
117 clocksource_register_hz(cs: &m68328_clk, TICKS_PER_JIFFY*HZ);
118}
119
120/***************************************************************************/
121
122int m68328_hwclk(int set, struct rtc_time *t)
123{
124 if (!set) {
125 long now = RTCTIME;
126 t->tm_year = 1;
127 t->tm_mon = 0;
128 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/***************************************************************************/
138

source code of linux/arch/m68k/68000/timers.c