2 * Copyright (C) 2001-2006 Storlink, Corp.
3 * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 #include <linux/interrupt.h>
11 #include <linux/irq.h>
13 #include <mach/hardware.h>
14 #include <mach/global_reg.h>
15 #include <asm/mach/time.h>
16 #include <linux/clockchips.h>
17 #include <linux/clocksource.h>
20 * Register definitions for the timers
23 #define TIMER1_BASE GEMINI_TIMER_BASE
24 #define TIMER2_BASE (GEMINI_TIMER_BASE + 0x10)
25 #define TIMER3_BASE (GEMINI_TIMER_BASE + 0x20)
27 #define TIMER_COUNT(BASE) (IO_ADDRESS(BASE) + 0x00)
28 #define TIMER_LOAD(BASE) (IO_ADDRESS(BASE) + 0x04)
29 #define TIMER_MATCH1(BASE) (IO_ADDRESS(BASE) + 0x08)
30 #define TIMER_MATCH2(BASE) (IO_ADDRESS(BASE) + 0x0C)
31 #define TIMER_CR (IO_ADDRESS(GEMINI_TIMER_BASE) + 0x30)
32 #define TIMER_INTR_STATE (IO_ADDRESS(GEMINI_TIMER_BASE) + 0x34)
33 #define TIMER_INTR_MASK (IO_ADDRESS(GEMINI_TIMER_BASE) + 0x38)
35 #define TIMER_1_CR_ENABLE (1 << 0)
36 #define TIMER_1_CR_CLOCK (1 << 1)
37 #define TIMER_1_CR_INT (1 << 2)
38 #define TIMER_2_CR_ENABLE (1 << 3)
39 #define TIMER_2_CR_CLOCK (1 << 4)
40 #define TIMER_2_CR_INT (1 << 5)
41 #define TIMER_3_CR_ENABLE (1 << 6)
42 #define TIMER_3_CR_CLOCK (1 << 7)
43 #define TIMER_3_CR_INT (1 << 8)
44 #define TIMER_1_CR_UPDOWN (1 << 9)
45 #define TIMER_2_CR_UPDOWN (1 << 10)
46 #define TIMER_3_CR_UPDOWN (1 << 11)
47 #define TIMER_DEFAULT_FLAGS (TIMER_1_CR_UPDOWN | \
51 #define TIMER_1_INT_MATCH1 (1 << 0)
52 #define TIMER_1_INT_MATCH2 (1 << 1)
53 #define TIMER_1_INT_OVERFLOW (1 << 2)
54 #define TIMER_2_INT_MATCH1 (1 << 3)
55 #define TIMER_2_INT_MATCH2 (1 << 4)
56 #define TIMER_2_INT_OVERFLOW (1 << 5)
57 #define TIMER_3_INT_MATCH1 (1 << 6)
58 #define TIMER_3_INT_MATCH2 (1 << 7)
59 #define TIMER_3_INT_OVERFLOW (1 << 8)
60 #define TIMER_INT_ALL_MASK 0x1ff
63 static unsigned int tick_rate;
65 static int gemini_timer_set_next_event(unsigned long cycles,
66 struct clock_event_device *evt)
70 /* Setup the match register */
71 cr = readl(TIMER_COUNT(TIMER1_BASE));
72 writel(cr + cycles, TIMER_MATCH1(TIMER1_BASE));
73 if (readl(TIMER_COUNT(TIMER1_BASE)) - cr > cycles)
79 static int gemini_timer_shutdown(struct clock_event_device *evt)
84 * Disable also for oneshot: the set_next() call will arm the timer
87 /* Stop timer and interrupt. */
89 cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
92 /* Setup counter start from 0 */
93 writel(0, TIMER_COUNT(TIMER1_BASE));
94 writel(0, TIMER_LOAD(TIMER1_BASE));
96 /* enable interrupt */
97 cr = readl(TIMER_INTR_MASK);
98 cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
99 cr |= TIMER_1_INT_MATCH1;
100 writel(cr, TIMER_INTR_MASK);
102 /* start the timer */
103 cr = readl(TIMER_CR);
104 cr |= TIMER_1_CR_ENABLE;
105 writel(cr, TIMER_CR);
110 static int gemini_timer_set_periodic(struct clock_event_device *evt)
112 u32 period = DIV_ROUND_CLOSEST(tick_rate, HZ);
115 /* Stop timer and interrupt */
116 cr = readl(TIMER_CR);
117 cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
118 writel(cr, TIMER_CR);
120 /* Setup timer to fire at 1/HT intervals. */
121 cr = 0xffffffff - (period - 1);
122 writel(cr, TIMER_COUNT(TIMER1_BASE));
123 writel(cr, TIMER_LOAD(TIMER1_BASE));
125 /* enable interrupt on overflow */
126 cr = readl(TIMER_INTR_MASK);
127 cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
128 cr |= TIMER_1_INT_OVERFLOW;
129 writel(cr, TIMER_INTR_MASK);
131 /* Start the timer */
132 cr = readl(TIMER_CR);
133 cr |= TIMER_1_CR_ENABLE;
134 cr |= TIMER_1_CR_INT;
135 writel(cr, TIMER_CR);
140 /* Use TIMER1 as clock event */
141 static struct clock_event_device gemini_clockevent = {
143 /* Reasonably fast and accurate clock event */
146 .features = CLOCK_EVT_FEAT_PERIODIC |
147 CLOCK_EVT_FEAT_ONESHOT,
148 .set_next_event = gemini_timer_set_next_event,
149 .set_state_shutdown = gemini_timer_shutdown,
150 .set_state_periodic = gemini_timer_set_periodic,
151 .set_state_oneshot = gemini_timer_shutdown,
152 .tick_resume = gemini_timer_shutdown,
156 * IRQ handler for the timer
158 static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
160 struct clock_event_device *evt = &gemini_clockevent;
162 evt->event_handler(evt);
166 static struct irqaction gemini_timer_irq = {
167 .name = "Gemini Timer Tick",
169 .handler = gemini_timer_interrupt,
173 * Set up timer interrupt, and return the current time in seconds.
175 void __init gemini_timer_init(void)
179 reg_v = readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS));
180 tick_rate = REG_TO_AHB_SPEED(reg_v) * 1000000;
182 printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
184 tick_rate /= 6; /* APB bus run AHB*(1/6) */
186 switch(reg_v & CPU_AHB_RATIO_MASK) {
188 printk(KERN_CONT "(1/1)\n");
191 printk(KERN_CONT "(3/2)\n");
194 printk(KERN_CONT "(24/13)\n");
197 printk(KERN_CONT "(2/1)\n");
202 * Reset the interrupt mask and status
204 writel(TIMER_INT_ALL_MASK, TIMER_INTR_MASK);
205 writel(0, TIMER_INTR_STATE);
206 writel(TIMER_DEFAULT_FLAGS, TIMER_CR);
209 * Setup clockevent timer (interrupt-driven.)
211 writel(0, TIMER_COUNT(TIMER1_BASE));
212 writel(0, TIMER_LOAD(TIMER1_BASE));
213 writel(0, TIMER_MATCH1(TIMER1_BASE));
214 writel(0, TIMER_MATCH2(TIMER1_BASE));
215 setup_irq(IRQ_TIMER1, &gemini_timer_irq);
216 gemini_clockevent.cpumask = cpumask_of(0);
217 clockevents_config_and_register(&gemini_clockevent, tick_rate,