Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 | /*
* Copyright (c) 2014 Zhang, Keguang <keguang.zhang@gmail.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/sizes.h>
#include <asm/time.h>
#include <loongson1.h>
#include <platform.h>
#ifdef CONFIG_CEVT_CSRC_LS1X
#if defined(CONFIG_TIMER_USE_PWM1)
#define LS1X_TIMER_BASE LS1X_PWM1_BASE
#define LS1X_TIMER_IRQ LS1X_PWM1_IRQ
#elif defined(CONFIG_TIMER_USE_PWM2)
#define LS1X_TIMER_BASE LS1X_PWM2_BASE
#define LS1X_TIMER_IRQ LS1X_PWM2_IRQ
#elif defined(CONFIG_TIMER_USE_PWM3)
#define LS1X_TIMER_BASE LS1X_PWM3_BASE
#define LS1X_TIMER_IRQ LS1X_PWM3_IRQ
#else
#define LS1X_TIMER_BASE LS1X_PWM0_BASE
#define LS1X_TIMER_IRQ LS1X_PWM0_IRQ
#endif
DEFINE_RAW_SPINLOCK(ls1x_timer_lock);
static void __iomem *timer_reg_base;
static uint32_t ls1x_jiffies_per_tick;
static inline void ls1x_pwmtimer_set_period(uint32_t period)
{
__raw_writel(period, timer_reg_base + PWM_HRC);
__raw_writel(period, timer_reg_base + PWM_LRC);
}
static inline void ls1x_pwmtimer_restart(void)
{
__raw_writel(0x0, timer_reg_base + PWM_CNT);
__raw_writel(INT_EN | CNT_EN, timer_reg_base + PWM_CTRL);
}
void __init ls1x_pwmtimer_init(void)
{
timer_reg_base = ioremap_nocache(LS1X_TIMER_BASE, SZ_16);
if (!timer_reg_base)
panic("Failed to remap timer registers");
ls1x_jiffies_per_tick = DIV_ROUND_CLOSEST(mips_hpt_frequency, HZ);
ls1x_pwmtimer_set_period(ls1x_jiffies_per_tick);
ls1x_pwmtimer_restart();
}
static u64 ls1x_clocksource_read(struct clocksource *cs)
{
unsigned long flags;
int count;
u32 jifs;
static int old_count;
static u32 old_jifs;
raw_spin_lock_irqsave(&ls1x_timer_lock, flags);
/*
* Although our caller may have the read side of xtime_lock,
* this is now a seqlock, and we are cheating in this routine
* by having side effects on state that we cannot undo if
* there is a collision on the seqlock and our caller has to
* retry. (Namely, old_jifs and old_count.) So we must treat
* jiffies as volatile despite the lock. We read jiffies
* before latching the timer count to guarantee that although
* the jiffies value might be older than the count (that is,
* the counter may underflow between the last point where
* jiffies was incremented and the point where we latch the
* count), it cannot be newer.
*/
jifs = jiffies;
/* read the count */
count = __raw_readl(timer_reg_base + PWM_CNT);
/*
* It's possible for count to appear to go the wrong way for this
* reason:
*
* The timer counter underflows, but we haven't handled the resulting
* interrupt and incremented jiffies yet.
*
* Previous attempts to handle these cases intelligently were buggy, so
* we just do the simple thing now.
*/
if (count < old_count && jifs == old_jifs)
count = old_count;
old_count = count;
old_jifs = jifs;
raw_spin_unlock_irqrestore(&ls1x_timer_lock, flags);
return (u64) (jifs * ls1x_jiffies_per_tick) + count;
}
static struct clocksource ls1x_clocksource = {
.name = "ls1x-pwmtimer",
.read = ls1x_clocksource_read,
.mask = CLOCKSOURCE_MASK(24),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static irqreturn_t ls1x_clockevent_isr(int irq, void *devid)
{
struct clock_event_device *cd = devid;
ls1x_pwmtimer_restart();
cd->event_handler(cd);
return IRQ_HANDLED;
}
static int ls1x_clockevent_set_state_periodic(struct clock_event_device *cd)
{
raw_spin_lock(&ls1x_timer_lock);
ls1x_pwmtimer_set_period(ls1x_jiffies_per_tick);
ls1x_pwmtimer_restart();
__raw_writel(INT_EN | CNT_EN, timer_reg_base + PWM_CTRL);
raw_spin_unlock(&ls1x_timer_lock);
return 0;
}
static int ls1x_clockevent_tick_resume(struct clock_event_device *cd)
{
raw_spin_lock(&ls1x_timer_lock);
__raw_writel(INT_EN | CNT_EN, timer_reg_base + PWM_CTRL);
raw_spin_unlock(&ls1x_timer_lock);
return 0;
}
static int ls1x_clockevent_set_state_shutdown(struct clock_event_device *cd)
{
raw_spin_lock(&ls1x_timer_lock);
__raw_writel(__raw_readl(timer_reg_base + PWM_CTRL) & ~CNT_EN,
timer_reg_base + PWM_CTRL);
raw_spin_unlock(&ls1x_timer_lock);
return 0;
}
static int ls1x_clockevent_set_next(unsigned long evt,
struct clock_event_device *cd)
{
raw_spin_lock(&ls1x_timer_lock);
ls1x_pwmtimer_set_period(evt);
ls1x_pwmtimer_restart();
raw_spin_unlock(&ls1x_timer_lock);
return 0;
}
static struct clock_event_device ls1x_clockevent = {
.name = "ls1x-pwmtimer",
.features = CLOCK_EVT_FEAT_PERIODIC,
.rating = 300,
.irq = LS1X_TIMER_IRQ,
.set_next_event = ls1x_clockevent_set_next,
.set_state_shutdown = ls1x_clockevent_set_state_shutdown,
.set_state_periodic = ls1x_clockevent_set_state_periodic,
.set_state_oneshot = ls1x_clockevent_set_state_shutdown,
.tick_resume = ls1x_clockevent_tick_resume,
};
static struct irqaction ls1x_pwmtimer_irqaction = {
.name = "ls1x-pwmtimer",
.handler = ls1x_clockevent_isr,
.dev_id = &ls1x_clockevent,
.flags = IRQF_PERCPU | IRQF_TIMER,
};
static void __init ls1x_time_init(void)
{
struct clock_event_device *cd = &ls1x_clockevent;
int ret;
if (!mips_hpt_frequency)
panic("Invalid timer clock rate");
ls1x_pwmtimer_init();
clockevent_set_clock(cd, mips_hpt_frequency);
cd->max_delta_ns = clockevent_delta2ns(0xffffff, cd);
cd->max_delta_ticks = 0xffffff;
cd->min_delta_ns = clockevent_delta2ns(0x000300, cd);
cd->min_delta_ticks = 0x000300;
cd->cpumask = cpumask_of(smp_processor_id());
clockevents_register_device(cd);
ls1x_clocksource.rating = 200 + mips_hpt_frequency / 10000000;
ret = clocksource_register_hz(&ls1x_clocksource, mips_hpt_frequency);
if (ret)
panic(KERN_ERR "Failed to register clocksource: %d\n", ret);
setup_irq(LS1X_TIMER_IRQ, &ls1x_pwmtimer_irqaction);
}
#endif /* CONFIG_CEVT_CSRC_LS1X */
void __init plat_time_init(void)
{
struct clk *clk = NULL;
/* initialize LS1X clocks */
ls1x_clk_init();
#ifdef CONFIG_CEVT_CSRC_LS1X
/* setup LS1X PWM timer */
clk = clk_get(NULL, "ls1x-pwmtimer");
if (IS_ERR(clk))
panic("unable to get timer clock, err=%ld", PTR_ERR(clk));
mips_hpt_frequency = clk_get_rate(clk);
ls1x_time_init();
#else
/* setup mips r4k timer */
clk = clk_get(NULL, "cpu_clk");
if (IS_ERR(clk))
panic("unable to get cpu clock, err=%ld", PTR_ERR(clk));
mips_hpt_frequency = clk_get_rate(clk) / 2;
#endif /* CONFIG_CEVT_CSRC_LS1X */
}
|