1 /***************************************************************************/
2
3 /*
4 * timers.c -- generic ColdFire hardware timer support.
5 *
6 * Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com>
7 */
8
9 /***************************************************************************/
10
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/sched.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/profile.h>
17 #include <linux/clocksource.h>
18 #include <asm/io.h>
19 #include <asm/traps.h>
20 #include <asm/machdep.h>
21 #include <asm/coldfire.h>
22 #include <asm/mcftimer.h>
23 #include <asm/mcfsim.h>
24
25 /***************************************************************************/
26
27 /*
28 * By default use timer1 as the system clock timer.
29 */
30 #define FREQ (MCF_BUSCLK / 16)
31 #define TA(a) (MCFTIMER_BASE1 + (a))
32
33 /*
34 * These provide the underlying interrupt vector support.
35 * Unfortunately it is a little different on each ColdFire.
36 */
37 void coldfire_profile_init(void);
38
39 #if defined(CONFIG_M532x)
40 #define __raw_readtrr __raw_readl
41 #define __raw_writetrr __raw_writel
42 #else
43 #define __raw_readtrr __raw_readw
44 #define __raw_writetrr __raw_writew
45 #endif
46
47 static u32 mcftmr_cycles_per_jiffy;
48 static u32 mcftmr_cnt;
49
50 /***************************************************************************/
51
mcftmr_tick(int irq,void * dummy)52 static irqreturn_t mcftmr_tick(int irq, void *dummy)
53 {
54 /* Reset the ColdFire timer */
55 __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
56
57 mcftmr_cnt += mcftmr_cycles_per_jiffy;
58 return arch_timer_interrupt(irq, dummy);
59 }
60
61 /***************************************************************************/
62
63 static struct irqaction mcftmr_timer_irq = {
64 .name = "timer",
65 .flags = IRQF_DISABLED | IRQF_TIMER,
66 .handler = mcftmr_tick,
67 };
68
69 /***************************************************************************/
70
mcftmr_read_clk(struct clocksource * cs)71 static cycle_t mcftmr_read_clk(struct clocksource *cs)
72 {
73 unsigned long flags;
74 u32 cycles;
75 u16 tcn;
76
77 local_irq_save(flags);
78 tcn = __raw_readw(TA(MCFTIMER_TCN));
79 cycles = mcftmr_cnt;
80 local_irq_restore(flags);
81
82 return cycles + tcn;
83 }
84
85 /***************************************************************************/
86
87 static struct clocksource mcftmr_clk = {
88 .name = "tmr",
89 .rating = 250,
90 .read = mcftmr_read_clk,
91 .mask = CLOCKSOURCE_MASK(32),
92 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
93 };
94
95 /***************************************************************************/
96
hw_timer_init(void)97 void hw_timer_init(void)
98 {
99 __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
100 mcftmr_cycles_per_jiffy = FREQ / HZ;
101 /*
102 * The coldfire timer runs from 0 to TRR included, then 0
103 * again and so on. It counts thus actually TRR + 1 steps
104 * for 1 tick, not TRR. So if you want n cycles,
105 * initialize TRR with n - 1.
106 */
107 __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
108 __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
109 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
110
111 clocksource_register_hz(&mcftmr_clk, FREQ);
112
113 setup_irq(MCF_IRQ_TIMER, &mcftmr_timer_irq);
114
115 #ifdef CONFIG_HIGHPROFILE
116 coldfire_profile_init();
117 #endif
118 }
119
120 /***************************************************************************/
121 #ifdef CONFIG_HIGHPROFILE
122 /***************************************************************************/
123
124 /*
125 * By default use timer2 as the profiler clock timer.
126 */
127 #define PA(a) (MCFTIMER_BASE2 + (a))
128
129 /*
130 * Choose a reasonably fast profile timer. Make it an odd value to
131 * try and get good coverage of kernel operations.
132 */
133 #define PROFILEHZ 1013
134
135 /*
136 * Use the other timer to provide high accuracy profiling info.
137 */
coldfire_profile_tick(int irq,void * dummy)138 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
139 {
140 /* Reset ColdFire timer2 */
141 __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
142 if (current->pid)
143 profile_tick(CPU_PROFILING);
144 return IRQ_HANDLED;
145 }
146
147 /***************************************************************************/
148
149 static struct irqaction coldfire_profile_irq = {
150 .name = "profile timer",
151 .flags = IRQF_DISABLED | IRQF_TIMER,
152 .handler = coldfire_profile_tick,
153 };
154
coldfire_profile_init(void)155 void coldfire_profile_init(void)
156 {
157 printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
158 PROFILEHZ);
159
160 /* Set up TIMER 2 as high speed profile clock */
161 __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
162
163 __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
164 __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
165 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
166
167 setup_irq(MCF_IRQ_PROFILER, &coldfire_profile_irq);
168 }
169
170 /***************************************************************************/
171 #endif /* CONFIG_HIGHPROFILE */
172 /***************************************************************************/
173