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478 lines
11 KiB
C
478 lines
11 KiB
C
![]() |
/*
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* Copyright (c) 2011 Samsung Electronics Co., Ltd.
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* http://www.samsung.com/
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*
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* samsung - Common hr-timer support (s3c and s5p)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/clockchips.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <clocksource/samsung_pwm.h>
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#include <asm/sched_clock.h>
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/*
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* Clocksource driver
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*/
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#define REG_TCFG0 0x00
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#define REG_TCFG1 0x04
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#define REG_TCON 0x08
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#define REG_TINT_CSTAT 0x44
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#define REG_TCNTB(chan) (0x0c + 12 * (chan))
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#define REG_TCMPB(chan) (0x10 + 12 * (chan))
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#define TCFG0_PRESCALER_MASK 0xff
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#define TCFG0_PRESCALER1_SHIFT 8
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#define TCFG1_SHIFT(x) ((x) * 4)
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#define TCFG1_MUX_MASK 0xf
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#define TCON_START(chan) (1 << (4 * (chan) + 0))
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#define TCON_MANUALUPDATE(chan) (1 << (4 * (chan) + 1))
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#define TCON_INVERT(chan) (1 << (4 * (chan) + 2))
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#define TCON_AUTORELOAD(chan) (1 << (4 * (chan) + 3))
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struct samsung_timer_source {
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unsigned int event_id;
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unsigned int source_id;
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unsigned int tcnt_max;
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unsigned int tscaler_div;
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unsigned int tdiv;
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};
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static struct samsung_pwm *pwm;
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static struct clk *timerclk;
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static struct samsung_timer_source timer_source;
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static unsigned long clock_count_per_tick;
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static void samsung_timer_set_prescale(struct samsung_pwm *pwm,
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unsigned int channel, u16 prescale)
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{
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unsigned long flags;
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u8 shift = 0;
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u32 reg;
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if (channel >= 2)
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shift = TCFG0_PRESCALER1_SHIFT;
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spin_lock_irqsave(&pwm->slock, flags);
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reg = readl(pwm->base + REG_TCFG0);
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reg &= ~(TCFG0_PRESCALER_MASK << shift);
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reg |= (prescale - 1) << shift;
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writel(reg, pwm->base + REG_TCFG0);
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spin_unlock_irqrestore(&pwm->slock, flags);
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}
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static void samsung_timer_set_divisor(struct samsung_pwm *pwm,
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unsigned int channel, u8 divisor)
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{
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u8 shift = TCFG1_SHIFT(channel);
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unsigned long flags;
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u32 reg;
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u8 bits;
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bits = (fls(divisor) - 1) - pwm->variant.div_base;
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spin_lock_irqsave(&pwm->slock, flags);
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reg = readl(pwm->base + REG_TCFG1);
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reg &= ~(TCFG1_MUX_MASK << shift);
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reg |= bits << shift;
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writel(reg, pwm->base + REG_TCFG1);
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spin_unlock_irqrestore(&pwm->slock, flags);
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}
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static void samsung_time_stop(unsigned int channel)
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{
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unsigned long tcon;
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unsigned long flags;
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if (channel > 0)
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++channel;
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spin_lock_irqsave(&pwm->slock, flags);
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tcon = __raw_readl(pwm->base + REG_TCON);
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tcon &= ~TCON_START(channel);
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__raw_writel(tcon, pwm->base + REG_TCON);
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spin_unlock_irqrestore(&pwm->slock, flags);
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}
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static void samsung_time_setup(unsigned int channel, unsigned long tcnt)
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{
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unsigned long tcon;
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unsigned long flags;
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unsigned int tcon_chan = channel;
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if (tcon_chan > 0)
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++tcon_chan;
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spin_lock_irqsave(&pwm->slock, flags);
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tcon = __raw_readl(pwm->base + REG_TCON);
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tcnt--;
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tcon &= ~(TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan));
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tcon |= TCON_MANUALUPDATE(tcon_chan);
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__raw_writel(tcnt, pwm->base + REG_TCNTB(channel));
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__raw_writel(tcnt, pwm->base + REG_TCMPB(channel));
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__raw_writel(tcon, pwm->base + REG_TCON);
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spin_unlock_irqrestore(&pwm->slock, flags);
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}
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static void samsung_time_start(unsigned int channel, bool periodic)
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{
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unsigned long tcon;
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unsigned long flags;
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if (channel > 0)
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++channel;
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spin_lock_irqsave(&pwm->slock, flags);
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tcon = __raw_readl(pwm->base + REG_TCON);
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tcon &= ~TCON_MANUALUPDATE(channel);
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tcon |= TCON_START(channel);
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if (periodic)
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tcon |= TCON_AUTORELOAD(channel);
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else
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tcon &= ~TCON_AUTORELOAD(channel);
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__raw_writel(tcon, pwm->base + REG_TCON);
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spin_unlock_irqrestore(&pwm->slock, flags);
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}
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static int samsung_set_next_event(unsigned long cycles,
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struct clock_event_device *evt)
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{
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samsung_time_setup(timer_source.event_id, cycles);
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samsung_time_start(timer_source.event_id, false);
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return 0;
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}
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static void samsung_timer_resume(void)
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{
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/* event timer restart */
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samsung_time_setup(timer_source.event_id, clock_count_per_tick);
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samsung_time_start(timer_source.event_id, true);
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/* source timer restart */
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samsung_time_setup(timer_source.source_id, timer_source.tcnt_max);
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samsung_time_start(timer_source.source_id, true);
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}
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static void samsung_set_mode(enum clock_event_mode mode,
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struct clock_event_device *evt)
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{
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samsung_time_stop(timer_source.event_id);
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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samsung_time_setup(timer_source.event_id, clock_count_per_tick);
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samsung_time_start(timer_source.event_id, true);
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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break;
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_SHUTDOWN:
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break;
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case CLOCK_EVT_MODE_RESUME:
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samsung_timer_resume();
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break;
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}
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}
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static struct clock_event_device time_event_device = {
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.name = "samsung_event_timer",
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.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
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.rating = 200,
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.set_next_event = samsung_set_next_event,
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.set_mode = samsung_set_mode,
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};
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static irqreturn_t samsung_clock_event_isr(int irq, void *dev_id)
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{
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struct clock_event_device *evt = dev_id;
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if (pwm->variant.has_tint_cstat) {
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u32 mask = (1 << timer_source.event_id);
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writel(mask | (mask << 5), pwm->base + REG_TINT_CSTAT);
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}
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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static struct irqaction samsung_clock_event_irq = {
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.name = "samsung_time_irq",
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.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
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.handler = samsung_clock_event_isr,
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.dev_id = &time_event_device,
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};
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static void __init samsung_clockevent_init(void)
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{
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unsigned long pclk;
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unsigned long clock_rate;
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unsigned int irq_number;
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pclk = clk_get_rate(timerclk);
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samsung_timer_set_prescale(pwm, timer_source.event_id,
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timer_source.tscaler_div);
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samsung_timer_set_divisor(pwm, timer_source.event_id,
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timer_source.tdiv);
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clock_rate = pclk / (timer_source.tscaler_div * timer_source.tdiv);
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clock_count_per_tick = clock_rate / HZ;
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time_event_device.cpumask = cpumask_of(0);
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clockevents_config_and_register(&time_event_device, clock_rate, 1, -1);
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irq_number = pwm->irq[timer_source.event_id];
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setup_irq(irq_number, &samsung_clock_event_irq);
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if (pwm->variant.has_tint_cstat) {
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u32 mask = (1 << timer_source.event_id);
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writel(mask | (mask << 5), pwm->base + REG_TINT_CSTAT);
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}
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}
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static void __iomem *samsung_timer_reg(void)
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{
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switch (timer_source.source_id) {
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case 0:
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case 1:
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case 2:
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case 3:
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return pwm->base + timer_source.source_id * 0x0c + 0x14;
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case 4:
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return pwm->base + 0x40;
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default:
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BUG();
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}
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}
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/*
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* Override the global weak sched_clock symbol with this
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* local implementation which uses the clocksource to get some
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* better resolution when scheduling the kernel. We accept that
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* this wraps around for now, since it is just a relative time
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* stamp. (Inspired by U300 implementation.)
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*/
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static u32 notrace samsung_read_sched_clock(void)
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{
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void __iomem *reg = samsung_timer_reg();
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if (!reg)
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return 0;
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return ~__raw_readl(reg);
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}
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static void __init samsung_clocksource_init(void)
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{
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void __iomem *reg = samsung_timer_reg();
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unsigned long pclk;
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unsigned long clock_rate;
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int ret;
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pclk = clk_get_rate(timerclk);
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samsung_timer_set_prescale(pwm, timer_source.source_id,
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timer_source.tscaler_div);
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samsung_timer_set_divisor(pwm, timer_source.source_id,
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timer_source.tdiv);
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clock_rate = pclk / (timer_source.tscaler_div * timer_source.tdiv);
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samsung_time_setup(timer_source.source_id, timer_source.tcnt_max);
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samsung_time_start(timer_source.source_id, true);
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setup_sched_clock(samsung_read_sched_clock,
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pwm->variant.bits, clock_rate);
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ret = clocksource_mmio_init(reg, "samsung_clocksource_timer",
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clock_rate, 250, pwm->variant.bits,
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clocksource_mmio_readl_down);
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if (ret)
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panic("samsung_clocksource_timer: can't register clocksource\n");
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}
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static void __init samsung_timer_resources(void)
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{
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timerclk = clk_get(NULL, "timers");
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if (IS_ERR(timerclk))
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panic("failed to get timers clock for timer");
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clk_prepare_enable(timerclk);
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timer_source.tcnt_max = (1UL << pwm->variant.bits) - 1;
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if (pwm->variant.bits == 16) {
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timer_source.tscaler_div = 25;
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timer_source.tdiv = 2;
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} else {
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timer_source.tscaler_div = 2;
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timer_source.tdiv = 1;
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}
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}
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/*
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* PWM master driver
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*/
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static void __init samsung_pwm_clocksource_init(void)
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{
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u8 mask;
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int channel;
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if (!pwm)
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panic("no pwm clocksource device found");
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mask = ~pwm->variant.output_mask & ((1 << SAMSUNG_PWM_NUM) - 1);
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channel = fls(mask) - 1;
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if (channel < 0)
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panic("failed to find PWM channel for clocksource");
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timer_source.source_id = channel;
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mask &= ~(1 << channel);
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channel = fls(mask) - 1;
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if (channel < 0)
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panic("failed to find PWM channel for clock event");
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timer_source.event_id = channel;
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samsung_timer_resources();
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samsung_clockevent_init();
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samsung_clocksource_init();
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}
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static void __init samsung_pwm_alloc(struct device_node *np,
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const struct samsung_pwm_variant *variant)
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{
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struct resource res;
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struct property *prop;
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const __be32 *cur;
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u32 val;
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int i;
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pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
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if (!pwm) {
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pr_err("%s: could not allocate PWM device struct\n", __func__);
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return;
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}
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memcpy(&pwm->variant, variant, sizeof(pwm->variant));
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spin_lock_init(&pwm->slock);
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for (i = 0; i < SAMSUNG_PWM_NUM; ++i)
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pwm->irq[i] = irq_of_parse_and_map(np, i);
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of_property_for_each_u32(np, "samsung,pwm-outputs", prop, cur, val) {
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if (val >= SAMSUNG_PWM_NUM) {
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pr_warning("%s: invalid channel index in samsung,pwm-outputs property\n",
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__func__);
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continue;
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}
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pwm->variant.output_mask |= 1 << val;
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}
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of_address_to_resource(np, 0, &res);
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if (!request_mem_region(res.start,
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resource_size(&res), "samsung-pwm")) {
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pr_err("%s: failed to request IO mem region\n", __func__);
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return;
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}
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pwm->base = ioremap(res.start, resource_size(&res));
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if (!pwm->base) {
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pr_err("%s: failed to map PWM registers\n", __func__);
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release_mem_region(res.start, resource_size(&res));
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return;
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}
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samsung_pwm_clocksource_init();
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}
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static const struct samsung_pwm_variant s3c24xx_variant = {
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.bits = 16,
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.div_base = 1,
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.has_tint_cstat = false,
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.tclk_mask = (1 << 4),
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};
|
||
|
|
||
|
static void __init s3c2410_pwm_clocksource_init(struct device_node *np)
|
||
|
{
|
||
|
samsung_pwm_alloc(np, &s3c24xx_variant);
|
||
|
}
|
||
|
CLOCKSOURCE_OF_DECLARE(s3c2410_pwm, "samsung,s3c2410-pwm", s3c2410_pwm_clocksource_init);
|
||
|
|
||
|
static const struct samsung_pwm_variant s3c64xx_variant = {
|
||
|
.bits = 32,
|
||
|
.div_base = 0,
|
||
|
.has_tint_cstat = true,
|
||
|
.tclk_mask = (1 << 7) | (1 << 6) | (1 << 5),
|
||
|
};
|
||
|
|
||
|
static void __init s3c64xx_pwm_clocksource_init(struct device_node *np)
|
||
|
{
|
||
|
samsung_pwm_alloc(np, &s3c64xx_variant);
|
||
|
}
|
||
|
CLOCKSOURCE_OF_DECLARE(s3c6400_pwm, "samsung,s3c6400-pwm", s3c64xx_pwm_clocksource_init);
|
||
|
|
||
|
static const struct samsung_pwm_variant s5p64x0_variant = {
|
||
|
.bits = 32,
|
||
|
.div_base = 0,
|
||
|
.has_tint_cstat = true,
|
||
|
.tclk_mask = 0,
|
||
|
};
|
||
|
|
||
|
static void __init s5p64x0_pwm_clocksource_init(struct device_node *np)
|
||
|
{
|
||
|
samsung_pwm_alloc(np, &s5p64x0_variant);
|
||
|
}
|
||
|
CLOCKSOURCE_OF_DECLARE(s5p6440_pwm, "samsung,s5p6440-pwm", s5p64x0_pwm_clocksource_init);
|
||
|
|
||
|
static const struct samsung_pwm_variant s5p_variant = {
|
||
|
.bits = 32,
|
||
|
.div_base = 0,
|
||
|
.has_tint_cstat = true,
|
||
|
.tclk_mask = (1 << 5),
|
||
|
};
|
||
|
|
||
|
static void __init s5p_pwm_clocksource_init(struct device_node *np)
|
||
|
{
|
||
|
samsung_pwm_alloc(np, &s5p_variant);
|
||
|
}
|
||
|
CLOCKSOURCE_OF_DECLARE(s5pc100_pwm, "samsung,s5pc100-pwm", s5p_pwm_clocksource_init);
|