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 /***************************************************************************/
29 
30 #if defined(CONFIG_DRAGEN2)
31 /* with a 33.16 MHz clock, this will give usec resolution to the time functions */
32 #define CLOCK_SOURCE	TCTL_CLKSOURCE_SYSCLK
33 #define CLOCK_PRE	7
34 #define TICKS_PER_JIFFY	41450
35 
36 #elif defined(CONFIG_XCOPILOT_BUGS)
37 /*
38  * The only thing I know is that CLK32 is not available on Xcopilot
39  * I have little idea about what frequency SYSCLK has on Xcopilot.
40  * The values for prescaler and compare registers were simply
41  * taken from the original source
42  */
43 #define CLOCK_SOURCE	TCTL_CLKSOURCE_SYSCLK
44 #define CLOCK_PRE	2
45 #define TICKS_PER_JIFFY	0xd7e4
46 
47 #else
48 /* default to using the 32Khz clock */
49 #define CLOCK_SOURCE	TCTL_CLKSOURCE_32KHZ
50 #define CLOCK_PRE	31
51 #define TICKS_PER_JIFFY	10
52 #endif
53 
54 static u32 m68328_tick_cnt;
55 
56 /***************************************************************************/
57 
hw_tick(int irq,void * dummy)58 static irqreturn_t hw_tick(int irq, void *dummy)
59 {
60 	/* Reset Timer1 */
61 	TSTAT &= 0;
62 
63 	m68328_tick_cnt += TICKS_PER_JIFFY;
64 	legacy_timer_tick(1);
65 	return IRQ_HANDLED;
66 }
67 
68 /***************************************************************************/
69 
m68328_read_clk(struct clocksource * cs)70 static u64 m68328_read_clk(struct clocksource *cs)
71 {
72 	unsigned long flags;
73 	u32 cycles;
74 
75 	local_irq_save(flags);
76 	cycles = m68328_tick_cnt + TCN;
77 	local_irq_restore(flags);
78 
79 	return cycles;
80 }
81 
82 /***************************************************************************/
83 
84 static struct clocksource m68328_clk = {
85 	.name	= "timer",
86 	.rating	= 250,
87 	.read	= m68328_read_clk,
88 	.mask	= CLOCKSOURCE_MASK(32),
89 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
90 };
91 
92 /***************************************************************************/
93 
hw_timer_init(void)94 void hw_timer_init(void)
95 {
96 	int ret;
97 
98 	/* disable timer 1 */
99 	TCTL = 0;
100 
101 	/* set ISR */
102 	ret = request_irq(TMR_IRQ_NUM, hw_tick, IRQF_TIMER, "timer", NULL);
103 	if (ret) {
104 		pr_err("Failed to request irq %d (timer): %pe\n", TMR_IRQ_NUM,
105 		       ERR_PTR(ret));
106 	}
107 
108 	/* Restart mode, Enable int, Set clock source */
109 	TCTL = TCTL_OM | TCTL_IRQEN | CLOCK_SOURCE;
110 	TPRER = CLOCK_PRE;
111 	TCMP = TICKS_PER_JIFFY;
112 
113 	/* Enable timer 1 */
114 	TCTL |= TCTL_TEN;
115 	clocksource_register_hz(&m68328_clk, TICKS_PER_JIFFY*HZ);
116 }
117 
118 /***************************************************************************/
119 
m68328_hwclk(int set,struct rtc_time * t)120 int m68328_hwclk(int set, struct rtc_time *t)
121 {
122 	if (!set) {
123 		long now = RTCTIME;
124 		t->tm_year = 1;
125 		t->tm_mon = 0;
126 		t->tm_mday = 1;
127 		t->tm_hour = (now >> 24) % 24;
128 		t->tm_min = (now >> 16) % 60;
129 		t->tm_sec = now % 60;
130 	}
131 
132 	return 0;
133 }
134 
135 /***************************************************************************/
136