blob: 9aa348658ae33905fe8b821bc3066d5e90a00d79 [file] [log] [blame]
Yoshinori Sato9d4436a2006-11-05 15:40:13 +09001/*
2 * arch/sh/kernel/timers/timer-cmt.c - CMT Timer Support
3 *
4 * Copyright (C) 2005 Yoshinori Sato
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10
11#include <linux/init.h>
12#include <linux/kernel.h>
13#include <linux/interrupt.h>
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090014#include <linux/seqlock.h>
15#include <asm/timer.h>
16#include <asm/rtc.h>
17#include <asm/io.h>
18#include <asm/irq.h>
19#include <asm/clock.h>
20
21#if defined(CONFIG_CPU_SUBTYPE_SH7619)
22#define CMT_CMSTR 0xf84a0070
23#define CMT_CMCSR_0 0xf84a0072
24#define CMT_CMCNT_0 0xf84a0074
25#define CMT_CMCOR_0 0xf84a0076
26#define CMT_CMCSR_1 0xf84a0078
27#define CMT_CMCNT_1 0xf84a007a
28#define CMT_CMCOR_1 0xf84a007c
29
30#define STBCR3 0xf80a0000
31#define cmt_clock_enable() do { ctrl_outb(ctrl_inb(STBCR3) & ~0x10, STBCR3); } while(0)
32#define CMT_CMCSR_INIT 0x0040
33#define CMT_CMCSR_CALIB 0x0000
Paul Mundta8f67f42007-11-26 19:54:02 +090034#elif defined(CONFIG_CPU_SUBTYPE_SH7203) || \
35 defined(CONFIG_CPU_SUBTYPE_SH7206) || \
36 defined(CONFIG_CPU_SUBTYPE_SH7263)
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090037#define CMT_CMSTR 0xfffec000
38#define CMT_CMCSR_0 0xfffec002
39#define CMT_CMCNT_0 0xfffec004
40#define CMT_CMCOR_0 0xfffec006
41
42#define STBCR4 0xfffe040c
43#define cmt_clock_enable() do { ctrl_outb(ctrl_inb(STBCR4) & ~0x04, STBCR4); } while(0)
44#define CMT_CMCSR_INIT 0x0040
45#define CMT_CMCSR_CALIB 0x0000
46#else
47#error "Unknown CPU SUBTYPE"
48#endif
49
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090050static unsigned long cmt_timer_get_offset(void)
51{
52 int count;
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090053 static unsigned short count_p = 0xffff; /* for the first call after boot */
54 static unsigned long jiffies_p = 0;
55
56 /*
57 * cache volatile jiffies temporarily; we have IRQs turned off.
58 */
59 unsigned long jiffies_t;
60
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090061 /* timer count may underflow right here */
62 count = ctrl_inw(CMT_CMCOR_0);
63 count -= ctrl_inw(CMT_CMCNT_0);
64
65 jiffies_t = jiffies;
66
67 /*
68 * avoiding timer inconsistencies (they are rare, but they happen)...
69 * there is one kind of problem that must be avoided here:
70 * 1. the timer counter underflows
71 */
72
73 if (jiffies_t == jiffies_p) {
74 if (count > count_p) {
75 /* the nutcase */
76 if (ctrl_inw(CMT_CMCSR_0) & 0x80) { /* Check CMF bit */
77 count -= LATCH;
78 } else {
79 printk("%s (): hardware timer problem?\n",
Harvey Harrison866e6b92008-03-04 15:23:47 -080080 __func__);
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090081 }
82 }
83 } else
84 jiffies_p = jiffies_t;
85
86 count_p = count;
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090087
88 count = ((LATCH-1) - count) * TICK_SIZE;
89 count = (count + LATCH/2) / LATCH;
90
91 return count;
92}
93
Paul Mundt710ee0c2006-11-05 16:48:42 +090094static irqreturn_t cmt_timer_interrupt(int irq, void *dev_id)
Yoshinori Sato9d4436a2006-11-05 15:40:13 +090095{
96 unsigned long timer_status;
97
98 /* Clear CMF bit */
99 timer_status = ctrl_inw(CMT_CMCSR_0);
100 timer_status &= ~0x80;
101 ctrl_outw(timer_status, CMT_CMCSR_0);
102
Paul Mundt710ee0c2006-11-05 16:48:42 +0900103 handle_timer_tick();
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900104
105 return IRQ_HANDLED;
106}
107
108static struct irqaction cmt_irq = {
109 .name = "timer",
110 .handler = cmt_timer_interrupt,
Bernhard Wallee9485ba2007-05-08 00:35:34 -0700111 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900112};
113
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900114static void cmt_clk_init(struct clk *clk)
115{
116 u8 divisor = CMT_CMCSR_INIT & 0x3;
117 ctrl_inw(CMT_CMCSR_0);
118 ctrl_outw(CMT_CMCSR_INIT, CMT_CMCSR_0);
Paul Mundt1d118562006-12-01 13:15:14 +0900119 clk->parent = clk_get(NULL, "module_clk");
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900120 clk->rate = clk->parent->rate / (8 << (divisor << 1));
121}
122
123static void cmt_clk_recalc(struct clk *clk)
124{
125 u8 divisor = ctrl_inw(CMT_CMCSR_0) & 0x3;
126 clk->rate = clk->parent->rate / (8 << (divisor << 1));
127}
128
129static struct clk_ops cmt_clk_ops = {
130 .init = cmt_clk_init,
131 .recalc = cmt_clk_recalc,
132};
133
134static struct clk cmt0_clk = {
135 .name = "cmt0_clk",
136 .ops = &cmt_clk_ops,
137};
138
139static int cmt_timer_start(void)
140{
141 ctrl_outw(ctrl_inw(CMT_CMSTR) | 0x01, CMT_CMSTR);
142 return 0;
143}
144
145static int cmt_timer_stop(void)
146{
147 ctrl_outw(ctrl_inw(CMT_CMSTR) & ~0x01, CMT_CMSTR);
148 return 0;
149}
150
151static int cmt_timer_init(void)
152{
153 unsigned long interval;
154
155 cmt_clock_enable();
156
Paul Mundt417528a2006-11-20 11:18:30 +0900157 setup_irq(CONFIG_SH_TIMER_IRQ, &cmt_irq);
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900158
Paul Mundt1d118562006-12-01 13:15:14 +0900159 cmt0_clk.parent = clk_get(NULL, "module_clk");
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900160
161 cmt_timer_stop();
162
163 interval = cmt0_clk.parent->rate / 8 / HZ;
164 printk(KERN_INFO "Interval = %ld\n", interval);
165
166 ctrl_outw(interval, CMT_CMCOR_0);
167
168 clk_register(&cmt0_clk);
169 clk_enable(&cmt0_clk);
170
171 cmt_timer_start();
172
173 return 0;
174}
175
Paul Mundtfa439722008-09-04 18:53:58 +0900176static struct sys_timer_ops cmt_timer_ops = {
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900177 .init = cmt_timer_init,
178 .start = cmt_timer_start,
179 .stop = cmt_timer_stop,
Paul Mundt710ee0c2006-11-05 16:48:42 +0900180#ifndef CONFIG_GENERIC_TIME
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900181 .get_offset = cmt_timer_get_offset,
Paul Mundt710ee0c2006-11-05 16:48:42 +0900182#endif
Yoshinori Sato9d4436a2006-11-05 15:40:13 +0900183};
184
185struct sys_timer cmt_timer = {
186 .name = "cmt",
187 .ops = &cmt_timer_ops,
188};