1 /* 2 * linux/arch/arm/mach-mmp/time.c 3 * 4 * Support for clocksource and clockevents 5 * 6 * Copyright (C) 2008 Marvell International Ltd. 7 * All rights reserved. 8 * 9 * 2008-04-11: Jason Chagas <Jason.chagas@marvell.com> 10 * 2008-10-08: Bin Yang <bin.yang@marvell.com> 11 * 12 * The timers module actually includes three timers, each timer with up to 13 * three match comparators. Timer #0 is used here in free-running mode as 14 * the clock source, and match comparator #1 used as clock event device. 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License version 2 as 18 * published by the Free Software Foundation. 19 */ 20 21 #include <linux/init.h> 22 #include <linux/kernel.h> 23 #include <linux/interrupt.h> 24 #include <linux/clockchips.h> 25 26 #include <linux/io.h> 27 #include <linux/irq.h> 28 #include <linux/of.h> 29 #include <linux/of_address.h> 30 #include <linux/of_irq.h> 31 #include <linux/sched_clock.h> 32 33 #include <mach/addr-map.h> 34 #include <mach/regs-timers.h> 35 #include <mach/regs-apbc.h> 36 #include <mach/irqs.h> 37 #include <mach/cputype.h> 38 #include <asm/mach/time.h> 39 40 #include "clock.h" 41 42 #ifdef CONFIG_CPU_MMP2 43 #define MMP_CLOCK_FREQ 6500000 44 #else 45 #define MMP_CLOCK_FREQ 3250000 46 #endif 47 48 #define TIMERS_VIRT_BASE TIMERS1_VIRT_BASE 49 50 #define MAX_DELTA (0xfffffffe) 51 #define MIN_DELTA (16) 52 53 static void __iomem *mmp_timer_base = TIMERS_VIRT_BASE; 54 55 /* 56 * FIXME: the timer needs some delay to stablize the counter capture 57 */ 58 static inline uint32_t timer_read(void) 59 { 60 int delay = 100; 61 62 __raw_writel(1, mmp_timer_base + TMR_CVWR(1)); 63 64 while (delay--) 65 cpu_relax(); 66 67 return __raw_readl(mmp_timer_base + TMR_CVWR(1)); 68 } 69 70 static u64 notrace mmp_read_sched_clock(void) 71 { 72 return timer_read(); 73 } 74 75 static irqreturn_t timer_interrupt(int irq, void *dev_id) 76 { 77 struct clock_event_device *c = dev_id; 78 79 /* 80 * Clear pending interrupt status. 81 */ 82 __raw_writel(0x01, mmp_timer_base + TMR_ICR(0)); 83 84 /* 85 * Disable timer 0. 86 */ 87 __raw_writel(0x02, mmp_timer_base + TMR_CER); 88 89 c->event_handler(c); 90 91 return IRQ_HANDLED; 92 } 93 94 static int timer_set_next_event(unsigned long delta, 95 struct clock_event_device *dev) 96 { 97 unsigned long flags; 98 99 local_irq_save(flags); 100 101 /* 102 * Disable timer 0. 103 */ 104 __raw_writel(0x02, mmp_timer_base + TMR_CER); 105 106 /* 107 * Clear and enable timer match 0 interrupt. 108 */ 109 __raw_writel(0x01, mmp_timer_base + TMR_ICR(0)); 110 __raw_writel(0x01, mmp_timer_base + TMR_IER(0)); 111 112 /* 113 * Setup new clockevent timer value. 114 */ 115 __raw_writel(delta - 1, mmp_timer_base + TMR_TN_MM(0, 0)); 116 117 /* 118 * Enable timer 0. 119 */ 120 __raw_writel(0x03, mmp_timer_base + TMR_CER); 121 122 local_irq_restore(flags); 123 124 return 0; 125 } 126 127 static int timer_set_shutdown(struct clock_event_device *evt) 128 { 129 unsigned long flags; 130 131 local_irq_save(flags); 132 /* disable the matching interrupt */ 133 __raw_writel(0x00, mmp_timer_base + TMR_IER(0)); 134 local_irq_restore(flags); 135 136 return 0; 137 } 138 139 static struct clock_event_device ckevt = { 140 .name = "clockevent", 141 .features = CLOCK_EVT_FEAT_ONESHOT, 142 .rating = 200, 143 .set_next_event = timer_set_next_event, 144 .set_state_shutdown = timer_set_shutdown, 145 .set_state_oneshot = timer_set_shutdown, 146 }; 147 148 static cycle_t clksrc_read(struct clocksource *cs) 149 { 150 return timer_read(); 151 } 152 153 static struct clocksource cksrc = { 154 .name = "clocksource", 155 .rating = 200, 156 .read = clksrc_read, 157 .mask = CLOCKSOURCE_MASK(32), 158 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 159 }; 160 161 static void __init timer_config(void) 162 { 163 uint32_t ccr = __raw_readl(mmp_timer_base + TMR_CCR); 164 165 __raw_writel(0x0, mmp_timer_base + TMR_CER); /* disable */ 166 167 ccr &= (cpu_is_mmp2()) ? (TMR_CCR_CS_0(0) | TMR_CCR_CS_1(0)) : 168 (TMR_CCR_CS_0(3) | TMR_CCR_CS_1(3)); 169 __raw_writel(ccr, mmp_timer_base + TMR_CCR); 170 171 /* set timer 0 to periodic mode, and timer 1 to free-running mode */ 172 __raw_writel(0x2, mmp_timer_base + TMR_CMR); 173 174 __raw_writel(0x1, mmp_timer_base + TMR_PLCR(0)); /* periodic */ 175 __raw_writel(0x7, mmp_timer_base + TMR_ICR(0)); /* clear status */ 176 __raw_writel(0x0, mmp_timer_base + TMR_IER(0)); 177 178 __raw_writel(0x0, mmp_timer_base + TMR_PLCR(1)); /* free-running */ 179 __raw_writel(0x7, mmp_timer_base + TMR_ICR(1)); /* clear status */ 180 __raw_writel(0x0, mmp_timer_base + TMR_IER(1)); 181 182 /* enable timer 1 counter */ 183 __raw_writel(0x2, mmp_timer_base + TMR_CER); 184 } 185 186 static struct irqaction timer_irq = { 187 .name = "timer", 188 .flags = IRQF_TIMER | IRQF_IRQPOLL, 189 .handler = timer_interrupt, 190 .dev_id = &ckevt, 191 }; 192 193 void __init timer_init(int irq) 194 { 195 timer_config(); 196 197 sched_clock_register(mmp_read_sched_clock, 32, MMP_CLOCK_FREQ); 198 199 ckevt.cpumask = cpumask_of(0); 200 201 setup_irq(irq, &timer_irq); 202 203 clocksource_register_hz(&cksrc, MMP_CLOCK_FREQ); 204 clockevents_config_and_register(&ckevt, MMP_CLOCK_FREQ, 205 MIN_DELTA, MAX_DELTA); 206 } 207 208 #ifdef CONFIG_OF 209 static const struct of_device_id mmp_timer_dt_ids[] = { 210 { .compatible = "mrvl,mmp-timer", }, 211 {} 212 }; 213 214 void __init mmp_dt_init_timer(void) 215 { 216 struct device_node *np; 217 int irq, ret; 218 219 np = of_find_matching_node(NULL, mmp_timer_dt_ids); 220 if (!np) { 221 ret = -ENODEV; 222 goto out; 223 } 224 225 irq = irq_of_parse_and_map(np, 0); 226 if (!irq) { 227 ret = -EINVAL; 228 goto out; 229 } 230 mmp_timer_base = of_iomap(np, 0); 231 if (!mmp_timer_base) { 232 ret = -ENOMEM; 233 goto out; 234 } 235 timer_init(irq); 236 return; 237 out: 238 pr_err("Failed to get timer from device tree with error:%d\n", ret); 239 } 240 #endif 241