1 // SPDX-License-Identifier: GPL-2.0
2 /***************************************************************************/
3
4 /*
5 * timers.c -- generic ColdFire hardware timer support.
6 *
7 * Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com>
8 */
9
10 /***************************************************************************/
11
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/interrupt.h>
16 #include <linux/irq.h>
17 #include <linux/profile.h>
18 #include <linux/clocksource.h>
19 #include <asm/io.h>
20 #include <asm/traps.h>
21 #include <asm/machdep.h>
22 #include <asm/coldfire.h>
23 #include <asm/mcftimer.h>
24 #include <asm/mcfsim.h>
25
26 /***************************************************************************/
27
28 /*
29 * By default use timer1 as the system clock timer.
30 */
31 #define FREQ (MCF_BUSCLK / 16)
32 #define TA(a) (MCFTIMER_BASE1 + (a))
33
34 /*
35 * These provide the underlying interrupt vector support.
36 * Unfortunately it is a little different on each ColdFire.
37 */
38 void coldfire_profile_init(void);
39
40 #if defined(CONFIG_M53xx) || defined(CONFIG_M5441x)
41 #define __raw_readtrr __raw_readl
42 #define __raw_writetrr __raw_writel
43 #else
44 #define __raw_readtrr __raw_readw
45 #define __raw_writetrr __raw_writew
46 #endif
47
48 static u32 mcftmr_cycles_per_jiffy;
49 static u32 mcftmr_cnt;
50
51 /***************************************************************************/
52
init_timer_irq(void)53 static void init_timer_irq(void)
54 {
55 #ifdef MCFSIM_ICR_AUTOVEC
56 /* Timer1 is always used as system timer */
57 writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL6 | MCFSIM_ICR_PRI3,
58 MCFSIM_TIMER1ICR);
59 mcf_mapirq2imr(MCF_IRQ_TIMER, MCFINTC_TIMER1);
60
61 #ifdef CONFIG_HIGHPROFILE
62 /* Timer2 is to be used as a high speed profile timer */
63 writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL7 | MCFSIM_ICR_PRI3,
64 MCFSIM_TIMER2ICR);
65 mcf_mapirq2imr(MCF_IRQ_PROFILER, MCFINTC_TIMER2);
66 #endif
67 #endif /* MCFSIM_ICR_AUTOVEC */
68 }
69
70 /***************************************************************************/
71
mcftmr_tick(int irq,void * dummy)72 static irqreturn_t mcftmr_tick(int irq, void *dummy)
73 {
74 /* Reset the ColdFire timer */
75 __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
76
77 mcftmr_cnt += mcftmr_cycles_per_jiffy;
78 legacy_timer_tick(1);
79 return IRQ_HANDLED;
80 }
81
82 /***************************************************************************/
83
mcftmr_read_clk(struct clocksource * cs)84 static u64 mcftmr_read_clk(struct clocksource *cs)
85 {
86 unsigned long flags;
87 u32 cycles;
88 u16 tcn;
89
90 local_irq_save(flags);
91 tcn = __raw_readw(TA(MCFTIMER_TCN));
92 cycles = mcftmr_cnt;
93 local_irq_restore(flags);
94
95 return cycles + tcn;
96 }
97
98 /***************************************************************************/
99
100 static struct clocksource mcftmr_clk = {
101 .name = "tmr",
102 .rating = 250,
103 .read = mcftmr_read_clk,
104 .mask = CLOCKSOURCE_MASK(32),
105 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
106 };
107
108 /***************************************************************************/
109
hw_timer_init(void)110 void hw_timer_init(void)
111 {
112 int r;
113
114 __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
115 mcftmr_cycles_per_jiffy = FREQ / HZ;
116 /*
117 * The coldfire timer runs from 0 to TRR included, then 0
118 * again and so on. It counts thus actually TRR + 1 steps
119 * for 1 tick, not TRR. So if you want n cycles,
120 * initialize TRR with n - 1.
121 */
122 __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
123 __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
124 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
125
126 clocksource_register_hz(&mcftmr_clk, FREQ);
127
128 init_timer_irq();
129 r = request_irq(MCF_IRQ_TIMER, mcftmr_tick, IRQF_TIMER, "timer", NULL);
130 if (r) {
131 pr_err("Failed to request irq %d (timer): %pe\n", MCF_IRQ_TIMER,
132 ERR_PTR(r));
133 }
134
135 #ifdef CONFIG_HIGHPROFILE
136 coldfire_profile_init();
137 #endif
138 }
139
140 /***************************************************************************/
141 #ifdef CONFIG_HIGHPROFILE
142 /***************************************************************************/
143
144 /*
145 * By default use timer2 as the profiler clock timer.
146 */
147 #define PA(a) (MCFTIMER_BASE2 + (a))
148
149 /*
150 * Choose a reasonably fast profile timer. Make it an odd value to
151 * try and get good coverage of kernel operations.
152 */
153 #define PROFILEHZ 1013
154
155 /*
156 * Use the other timer to provide high accuracy profiling info.
157 */
coldfire_profile_tick(int irq,void * dummy)158 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
159 {
160 /* Reset ColdFire timer2 */
161 __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
162 if (current->pid)
163 profile_tick(CPU_PROFILING);
164 return IRQ_HANDLED;
165 }
166
167 /***************************************************************************/
168
coldfire_profile_init(void)169 void coldfire_profile_init(void)
170 {
171 int ret;
172
173 printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
174 PROFILEHZ);
175
176 /* Set up TIMER 2 as high speed profile clock */
177 __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
178
179 __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
180 __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
181 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
182
183 ret = request_irq(MCF_IRQ_PROFILER, coldfire_profile_tick, IRQF_TIMER,
184 "profile timer", NULL);
185 if (ret) {
186 pr_err("Failed to request irq %d (profile timer): %pe\n",
187 MCF_IRQ_PROFILER, ERR_PTR(ret));
188 }
189 }
190
191 /***************************************************************************/
192 #endif /* CONFIG_HIGHPROFILE */
193 /***************************************************************************/
194