xref: /openbmc/linux/arch/microblaze/kernel/timer.c (revision b04b4f78)
1 /*
2  * Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
3  * Copyright (C) 2007-2009 PetaLogix
4  * Copyright (C) 2006 Atmark Techno, Inc.
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/param.h>
14 #include <linux/interrupt.h>
15 #include <linux/profile.h>
16 #include <linux/irq.h>
17 #include <linux/delay.h>
18 #include <linux/sched.h>
19 #include <linux/spinlock.h>
20 #include <linux/err.h>
21 #include <linux/clk.h>
22 #include <linux/clocksource.h>
23 #include <linux/clockchips.h>
24 #include <linux/io.h>
25 #include <asm/cpuinfo.h>
26 #include <asm/setup.h>
27 #include <asm/prom.h>
28 #include <asm/irq.h>
29 #include <asm/system.h>
30 
31 #ifdef CONFIG_SELFMOD_TIMER
32 #include <asm/selfmod.h>
33 #define TIMER_BASE	BARRIER_BASE_ADDR
34 #else
35 static unsigned int timer_baseaddr;
36 #define TIMER_BASE	timer_baseaddr
37 #endif
38 
39 #define TCSR0	(0x00)
40 #define TLR0	(0x04)
41 #define TCR0	(0x08)
42 #define TCSR1	(0x10)
43 #define TLR1	(0x14)
44 #define TCR1	(0x18)
45 
46 #define TCSR_MDT	(1<<0)
47 #define TCSR_UDT	(1<<1)
48 #define TCSR_GENT	(1<<2)
49 #define TCSR_CAPT	(1<<3)
50 #define TCSR_ARHT	(1<<4)
51 #define TCSR_LOAD	(1<<5)
52 #define TCSR_ENIT	(1<<6)
53 #define TCSR_ENT	(1<<7)
54 #define TCSR_TINT	(1<<8)
55 #define TCSR_PWMA	(1<<9)
56 #define TCSR_ENALL	(1<<10)
57 
58 static inline void microblaze_timer0_stop(void)
59 {
60 	out_be32(TIMER_BASE + TCSR0, in_be32(TIMER_BASE + TCSR0) & ~TCSR_ENT);
61 }
62 
63 static inline void microblaze_timer0_start_periodic(unsigned long load_val)
64 {
65 	if (!load_val)
66 		load_val = 1;
67 	out_be32(TIMER_BASE + TLR0, load_val); /* loading value to timer reg */
68 
69 	/* load the initial value */
70 	out_be32(TIMER_BASE + TCSR0, TCSR_LOAD);
71 
72 	/* see timer data sheet for detail
73 	 * !ENALL - don't enable 'em all
74 	 * !PWMA - disable pwm
75 	 * TINT - clear interrupt status
76 	 * ENT- enable timer itself
77 	 * EINT - enable interrupt
78 	 * !LOAD - clear the bit to let go
79 	 * ARHT - auto reload
80 	 * !CAPT - no external trigger
81 	 * !GENT - no external signal
82 	 * UDT - set the timer as down counter
83 	 * !MDT0 - generate mode
84 	 */
85 	out_be32(TIMER_BASE + TCSR0,
86 			TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT);
87 }
88 
89 static inline void microblaze_timer0_start_oneshot(unsigned long load_val)
90 {
91 	if (!load_val)
92 		load_val = 1;
93 	out_be32(TIMER_BASE + TLR0, load_val); /* loading value to timer reg */
94 
95 	/* load the initial value */
96 	out_be32(TIMER_BASE + TCSR0, TCSR_LOAD);
97 
98 	out_be32(TIMER_BASE + TCSR0,
99 			TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT);
100 }
101 
102 static int microblaze_timer_set_next_event(unsigned long delta,
103 					struct clock_event_device *dev)
104 {
105 	pr_debug("%s: next event, delta %x\n", __func__, (u32)delta);
106 	microblaze_timer0_start_oneshot(delta);
107 	return 0;
108 }
109 
110 static void microblaze_timer_set_mode(enum clock_event_mode mode,
111 				struct clock_event_device *evt)
112 {
113 	switch (mode) {
114 	case CLOCK_EVT_MODE_PERIODIC:
115 		printk(KERN_INFO "%s: periodic\n", __func__);
116 		microblaze_timer0_start_periodic(cpuinfo.freq_div_hz);
117 		break;
118 	case CLOCK_EVT_MODE_ONESHOT:
119 		printk(KERN_INFO "%s: oneshot\n", __func__);
120 		break;
121 	case CLOCK_EVT_MODE_UNUSED:
122 		printk(KERN_INFO "%s: unused\n", __func__);
123 		break;
124 	case CLOCK_EVT_MODE_SHUTDOWN:
125 		printk(KERN_INFO "%s: shutdown\n", __func__);
126 		microblaze_timer0_stop();
127 		break;
128 	case CLOCK_EVT_MODE_RESUME:
129 		printk(KERN_INFO "%s: resume\n", __func__);
130 		break;
131 	}
132 }
133 
134 static struct clock_event_device clockevent_microblaze_timer = {
135 	.name		= "microblaze_clockevent",
136 	.features       = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
137 	.shift		= 24,
138 	.rating		= 300,
139 	.set_next_event	= microblaze_timer_set_next_event,
140 	.set_mode	= microblaze_timer_set_mode,
141 };
142 
143 static inline void timer_ack(void)
144 {
145 	out_be32(TIMER_BASE + TCSR0, in_be32(TIMER_BASE + TCSR0));
146 }
147 
148 static irqreturn_t timer_interrupt(int irq, void *dev_id)
149 {
150 	struct clock_event_device *evt = &clockevent_microblaze_timer;
151 #ifdef CONFIG_HEART_BEAT
152 	heartbeat();
153 #endif
154 	timer_ack();
155 	evt->event_handler(evt);
156 	return IRQ_HANDLED;
157 }
158 
159 static struct irqaction timer_irqaction = {
160 	.handler = timer_interrupt,
161 	.flags = IRQF_DISABLED | IRQF_TIMER,
162 	.name = "timer",
163 	.dev_id = &clockevent_microblaze_timer,
164 };
165 
166 static __init void microblaze_clockevent_init(void)
167 {
168 	clockevent_microblaze_timer.mult =
169 		div_sc(cpuinfo.cpu_clock_freq, NSEC_PER_SEC,
170 				clockevent_microblaze_timer.shift);
171 	clockevent_microblaze_timer.max_delta_ns =
172 		clockevent_delta2ns((u32)~0, &clockevent_microblaze_timer);
173 	clockevent_microblaze_timer.min_delta_ns =
174 		clockevent_delta2ns(1, &clockevent_microblaze_timer);
175 	clockevent_microblaze_timer.cpumask = cpumask_of(0);
176 	clockevents_register_device(&clockevent_microblaze_timer);
177 }
178 
179 static cycle_t microblaze_read(struct clocksource *cs)
180 {
181 	/* reading actual value of timer 1 */
182 	return (cycle_t) (in_be32(TIMER_BASE + TCR1));
183 }
184 
185 static struct clocksource clocksource_microblaze = {
186 	.name		= "microblaze_clocksource",
187 	.rating		= 300,
188 	.read		= microblaze_read,
189 	.mask		= CLOCKSOURCE_MASK(32),
190 	.shift		= 24, /* I can shift it */
191 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
192 };
193 
194 static int __init microblaze_clocksource_init(void)
195 {
196 	clocksource_microblaze.mult =
197 			clocksource_hz2mult(cpuinfo.cpu_clock_freq,
198 						clocksource_microblaze.shift);
199 	if (clocksource_register(&clocksource_microblaze))
200 		panic("failed to register clocksource");
201 
202 	/* stop timer1 */
203 	out_be32(TIMER_BASE + TCSR1, in_be32(TIMER_BASE + TCSR1) & ~TCSR_ENT);
204 	/* start timer1 - up counting without interrupt */
205 	out_be32(TIMER_BASE + TCSR1, TCSR_TINT|TCSR_ENT|TCSR_ARHT);
206 	return 0;
207 }
208 
209 void __init time_init(void)
210 {
211 	u32 irq, i = 0;
212 	u32 timer_num = 1;
213 	struct device_node *timer = NULL;
214 #ifdef CONFIG_SELFMOD_TIMER
215 	unsigned int timer_baseaddr = 0;
216 	int arr_func[] = {
217 				(int)&microblaze_read,
218 				(int)&timer_interrupt,
219 				(int)&microblaze_clocksource_init,
220 				(int)&microblaze_timer_set_mode,
221 				(int)&microblaze_timer_set_next_event,
222 				0
223 			};
224 #endif
225 	char *timer_list[] = {
226 				"xlnx,xps-timer-1.00.a",
227 				"xlnx,opb-timer-1.00.b",
228 				"xlnx,opb-timer-1.00.a",
229 				NULL
230 			};
231 
232 	for (i = 0; timer_list[i] != NULL; i++) {
233 		timer = of_find_compatible_node(NULL, NULL, timer_list[i]);
234 		if (timer)
235 			break;
236 	}
237 
238 	timer_baseaddr = *(int *) of_get_property(timer, "reg", NULL);
239 	timer_baseaddr = (unsigned long) ioremap(timer_baseaddr, PAGE_SIZE);
240 	irq = *(int *) of_get_property(timer, "interrupts", NULL);
241 	timer_num =
242 		*(int *) of_get_property(timer, "xlnx,one-timer-only", NULL);
243 	if (timer_num) {
244 		printk(KERN_EMERG "Please enable two timers in HW\n");
245 		BUG();
246 	}
247 
248 #ifdef CONFIG_SELFMOD_TIMER
249 	selfmod_function((int *) arr_func, timer_baseaddr);
250 #endif
251 	printk(KERN_INFO "%s #0 at 0x%08x, irq=%d\n",
252 		timer_list[i], timer_baseaddr, irq);
253 
254 	cpuinfo.freq_div_hz = cpuinfo.cpu_clock_freq / HZ;
255 
256 	setup_irq(irq, &timer_irqaction);
257 #ifdef CONFIG_HEART_BEAT
258 	setup_heartbeat();
259 #endif
260 	microblaze_clocksource_init();
261 	microblaze_clockevent_init();
262 }
263