xref: /openbmc/linux/arch/microblaze/kernel/timer.c (revision e8e0929d)
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 <linux/bug.h>
26 #include <asm/cpuinfo.h>
27 #include <asm/setup.h>
28 #include <asm/prom.h>
29 #include <asm/irq.h>
30 #include <asm/system.h>
31 
32 #ifdef CONFIG_SELFMOD_TIMER
33 #include <asm/selfmod.h>
34 #define TIMER_BASE	BARRIER_BASE_ADDR
35 #else
36 static unsigned int timer_baseaddr;
37 #define TIMER_BASE	timer_baseaddr
38 #endif
39 
40 #define TCSR0	(0x00)
41 #define TLR0	(0x04)
42 #define TCR0	(0x08)
43 #define TCSR1	(0x10)
44 #define TLR1	(0x14)
45 #define TCR1	(0x18)
46 
47 #define TCSR_MDT	(1<<0)
48 #define TCSR_UDT	(1<<1)
49 #define TCSR_GENT	(1<<2)
50 #define TCSR_CAPT	(1<<3)
51 #define TCSR_ARHT	(1<<4)
52 #define TCSR_LOAD	(1<<5)
53 #define TCSR_ENIT	(1<<6)
54 #define TCSR_ENT	(1<<7)
55 #define TCSR_TINT	(1<<8)
56 #define TCSR_PWMA	(1<<9)
57 #define TCSR_ENALL	(1<<10)
58 
59 static inline void microblaze_timer0_stop(void)
60 {
61 	out_be32(TIMER_BASE + TCSR0, in_be32(TIMER_BASE + TCSR0) & ~TCSR_ENT);
62 }
63 
64 static inline void microblaze_timer0_start_periodic(unsigned long load_val)
65 {
66 	if (!load_val)
67 		load_val = 1;
68 	out_be32(TIMER_BASE + TLR0, load_val); /* loading value to timer reg */
69 
70 	/* load the initial value */
71 	out_be32(TIMER_BASE + TCSR0, TCSR_LOAD);
72 
73 	/* see timer data sheet for detail
74 	 * !ENALL - don't enable 'em all
75 	 * !PWMA - disable pwm
76 	 * TINT - clear interrupt status
77 	 * ENT- enable timer itself
78 	 * EINT - enable interrupt
79 	 * !LOAD - clear the bit to let go
80 	 * ARHT - auto reload
81 	 * !CAPT - no external trigger
82 	 * !GENT - no external signal
83 	 * UDT - set the timer as down counter
84 	 * !MDT0 - generate mode
85 	 */
86 	out_be32(TIMER_BASE + TCSR0,
87 			TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT);
88 }
89 
90 static inline void microblaze_timer0_start_oneshot(unsigned long load_val)
91 {
92 	if (!load_val)
93 		load_val = 1;
94 	out_be32(TIMER_BASE + TLR0, load_val); /* loading value to timer reg */
95 
96 	/* load the initial value */
97 	out_be32(TIMER_BASE + TCSR0, TCSR_LOAD);
98 
99 	out_be32(TIMER_BASE + TCSR0,
100 			TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT);
101 }
102 
103 static int microblaze_timer_set_next_event(unsigned long delta,
104 					struct clock_event_device *dev)
105 {
106 	pr_debug("%s: next event, delta %x\n", __func__, (u32)delta);
107 	microblaze_timer0_start_oneshot(delta);
108 	return 0;
109 }
110 
111 static void microblaze_timer_set_mode(enum clock_event_mode mode,
112 				struct clock_event_device *evt)
113 {
114 	switch (mode) {
115 	case CLOCK_EVT_MODE_PERIODIC:
116 		printk(KERN_INFO "%s: periodic\n", __func__);
117 		microblaze_timer0_start_periodic(cpuinfo.freq_div_hz);
118 		break;
119 	case CLOCK_EVT_MODE_ONESHOT:
120 		printk(KERN_INFO "%s: oneshot\n", __func__);
121 		break;
122 	case CLOCK_EVT_MODE_UNUSED:
123 		printk(KERN_INFO "%s: unused\n", __func__);
124 		break;
125 	case CLOCK_EVT_MODE_SHUTDOWN:
126 		printk(KERN_INFO "%s: shutdown\n", __func__);
127 		microblaze_timer0_stop();
128 		break;
129 	case CLOCK_EVT_MODE_RESUME:
130 		printk(KERN_INFO "%s: resume\n", __func__);
131 		break;
132 	}
133 }
134 
135 static struct clock_event_device clockevent_microblaze_timer = {
136 	.name		= "microblaze_clockevent",
137 	.features       = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
138 	.shift		= 24,
139 	.rating		= 300,
140 	.set_next_event	= microblaze_timer_set_next_event,
141 	.set_mode	= microblaze_timer_set_mode,
142 };
143 
144 static inline void timer_ack(void)
145 {
146 	out_be32(TIMER_BASE + TCSR0, in_be32(TIMER_BASE + TCSR0));
147 }
148 
149 static irqreturn_t timer_interrupt(int irq, void *dev_id)
150 {
151 	struct clock_event_device *evt = &clockevent_microblaze_timer;
152 #ifdef CONFIG_HEART_BEAT
153 	heartbeat();
154 #endif
155 	timer_ack();
156 	evt->event_handler(evt);
157 	return IRQ_HANDLED;
158 }
159 
160 static struct irqaction timer_irqaction = {
161 	.handler = timer_interrupt,
162 	.flags = IRQF_DISABLED | IRQF_TIMER,
163 	.name = "timer",
164 	.dev_id = &clockevent_microblaze_timer,
165 };
166 
167 static __init void microblaze_clockevent_init(void)
168 {
169 	clockevent_microblaze_timer.mult =
170 		div_sc(cpuinfo.cpu_clock_freq, NSEC_PER_SEC,
171 				clockevent_microblaze_timer.shift);
172 	clockevent_microblaze_timer.max_delta_ns =
173 		clockevent_delta2ns((u32)~0, &clockevent_microblaze_timer);
174 	clockevent_microblaze_timer.min_delta_ns =
175 		clockevent_delta2ns(1, &clockevent_microblaze_timer);
176 	clockevent_microblaze_timer.cpumask = cpumask_of(0);
177 	clockevents_register_device(&clockevent_microblaze_timer);
178 }
179 
180 static cycle_t microblaze_read(struct clocksource *cs)
181 {
182 	/* reading actual value of timer 1 */
183 	return (cycle_t) (in_be32(TIMER_BASE + TCR1));
184 }
185 
186 static struct clocksource clocksource_microblaze = {
187 	.name		= "microblaze_clocksource",
188 	.rating		= 300,
189 	.read		= microblaze_read,
190 	.mask		= CLOCKSOURCE_MASK(32),
191 	.shift		= 24, /* I can shift it */
192 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
193 };
194 
195 static int __init microblaze_clocksource_init(void)
196 {
197 	clocksource_microblaze.mult =
198 			clocksource_hz2mult(cpuinfo.cpu_clock_freq,
199 						clocksource_microblaze.shift);
200 	if (clocksource_register(&clocksource_microblaze))
201 		panic("failed to register clocksource");
202 
203 	/* stop timer1 */
204 	out_be32(TIMER_BASE + TCSR1, in_be32(TIMER_BASE + TCSR1) & ~TCSR_ENT);
205 	/* start timer1 - up counting without interrupt */
206 	out_be32(TIMER_BASE + TCSR1, TCSR_TINT|TCSR_ENT|TCSR_ARHT);
207 	return 0;
208 }
209 
210 void __init time_init(void)
211 {
212 	u32 irq, i = 0;
213 	u32 timer_num = 1;
214 	struct device_node *timer = NULL;
215 #ifdef CONFIG_SELFMOD_TIMER
216 	unsigned int timer_baseaddr = 0;
217 	int arr_func[] = {
218 				(int)&microblaze_read,
219 				(int)&timer_interrupt,
220 				(int)&microblaze_clocksource_init,
221 				(int)&microblaze_timer_set_mode,
222 				(int)&microblaze_timer_set_next_event,
223 				0
224 			};
225 #endif
226 	char *timer_list[] = {
227 				"xlnx,xps-timer-1.00.a",
228 				"xlnx,opb-timer-1.00.b",
229 				"xlnx,opb-timer-1.00.a",
230 				NULL
231 			};
232 
233 	for (i = 0; timer_list[i] != NULL; i++) {
234 		timer = of_find_compatible_node(NULL, NULL, timer_list[i]);
235 		if (timer)
236 			break;
237 	}
238 	BUG_ON(!timer);
239 
240 	timer_baseaddr = *(int *) of_get_property(timer, "reg", NULL);
241 	timer_baseaddr = (unsigned long) ioremap(timer_baseaddr, PAGE_SIZE);
242 	irq = *(int *) of_get_property(timer, "interrupts", NULL);
243 	timer_num =
244 		*(int *) of_get_property(timer, "xlnx,one-timer-only", NULL);
245 	if (timer_num) {
246 		printk(KERN_EMERG "Please enable two timers in HW\n");
247 		BUG();
248 	}
249 
250 #ifdef CONFIG_SELFMOD_TIMER
251 	selfmod_function((int *) arr_func, timer_baseaddr);
252 #endif
253 	printk(KERN_INFO "%s #0 at 0x%08x, irq=%d\n",
254 		timer_list[i], timer_baseaddr, irq);
255 
256 	cpuinfo.freq_div_hz = cpuinfo.cpu_clock_freq / HZ;
257 
258 	setup_irq(irq, &timer_irqaction);
259 #ifdef CONFIG_HEART_BEAT
260 	setup_heartbeat();
261 #endif
262 	microblaze_clocksource_init();
263 	microblaze_clockevent_init();
264 }
265