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Release 4.14 drivers/clocksource/samsung_pwm_timer.c

/*
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com/
 *
 * samsung - Common hr-timer support (s3c and s5p)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/sched_clock.h>

#include <clocksource/samsung_pwm.h>


/*
 * Clocksource driver
 */


#define REG_TCFG0			0x00

#define REG_TCFG1			0x04

#define REG_TCON			0x08

#define REG_TINT_CSTAT			0x44


#define REG_TCNTB(chan)			(0x0c + 12 * (chan))

#define REG_TCMPB(chan)			(0x10 + 12 * (chan))


#define TCFG0_PRESCALER_MASK		0xff

#define TCFG0_PRESCALER1_SHIFT		8


#define TCFG1_SHIFT(x)	  		((x) * 4)

#define TCFG1_MUX_MASK	  		0xf

/*
 * Each channel occupies 4 bits in TCON register, but there is a gap of 4
 * bits (one channel) after channel 0, so channels have different numbering
 * when accessing TCON register.
 *
 * In addition, the location of autoreload bit for channel 4 (TCON channel 5)
 * in its set of bits is 2 as opposed to 3 for other channels.
 */

#define TCON_START(chan)		(1 << (4 * (chan) + 0))

#define TCON_MANUALUPDATE(chan)		(1 << (4 * (chan) + 1))

#define TCON_INVERT(chan)		(1 << (4 * (chan) + 2))

#define _TCON_AUTORELOAD(chan)		(1 << (4 * (chan) + 3))

#define _TCON_AUTORELOAD4(chan)		(1 << (4 * (chan) + 2))

#define TCON_AUTORELOAD(chan)		\
	((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))


DEFINE_SPINLOCK(samsung_pwm_lock);

EXPORT_SYMBOL(samsung_pwm_lock);


struct samsung_pwm_clocksource {
	
void __iomem *base;
	
void __iomem *source_reg;
	
unsigned int irq[SAMSUNG_PWM_NUM];
	
struct samsung_pwm_variant variant;

	
struct clk *timerclk;

	
unsigned int event_id;
	
unsigned int source_id;
	
unsigned int tcnt_max;
	
unsigned int tscaler_div;
	
unsigned int tdiv;

	
unsigned long clock_count_per_tick;
};


static struct samsung_pwm_clocksource pwm;


static void samsung_timer_set_prescale(unsigned int channel, u16 prescale) { unsigned long flags; u8 shift = 0; u32 reg; if (channel >= 2) shift = TCFG0_PRESCALER1_SHIFT; spin_lock_irqsave(&samsung_pwm_lock, flags); reg = readl(pwm.base + REG_TCFG0); reg &= ~(TCFG0_PRESCALER_MASK << shift); reg |= (prescale - 1) << shift; writel(reg, pwm.base + REG_TCFG0); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static void samsung_timer_set_divisor(unsigned int channel, u8 divisor) { u8 shift = TCFG1_SHIFT(channel); unsigned long flags; u32 reg; u8 bits; bits = (fls(divisor) - 1) - pwm.variant.div_base; spin_lock_irqsave(&samsung_pwm_lock, flags); reg = readl(pwm.base + REG_TCFG1); reg &= ~(TCFG1_MUX_MASK << shift); reg |= bits << shift; writel(reg, pwm.base + REG_TCFG1); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static void samsung_time_stop(unsigned int channel) { unsigned long tcon; unsigned long flags; if (channel > 0) ++channel; spin_lock_irqsave(&samsung_pwm_lock, flags); tcon = readl_relaxed(pwm.base + REG_TCON); tcon &= ~TCON_START(channel); writel_relaxed(tcon, pwm.base + REG_TCON); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static void samsung_time_setup(unsigned int channel, unsigned long tcnt) { unsigned long tcon; unsigned long flags; unsigned int tcon_chan = channel; if (tcon_chan > 0) ++tcon_chan; spin_lock_irqsave(&samsung_pwm_lock, flags); tcon = readl_relaxed(pwm.base + REG_TCON); tcon &= ~(TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan)); tcon |= TCON_MANUALUPDATE(tcon_chan); writel_relaxed(tcnt, pwm.base + REG_TCNTB(channel)); writel_relaxed(tcnt, pwm.base + REG_TCMPB(channel)); writel_relaxed(tcon, pwm.base + REG_TCON); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static void samsung_time_start(unsigned int channel, bool periodic) { unsigned long tcon; unsigned long flags; if (channel > 0) ++channel; spin_lock_irqsave(&samsung_pwm_lock, flags); tcon = readl_relaxed(pwm.base + REG_TCON); tcon &= ~TCON_MANUALUPDATE(channel); tcon |= TCON_START(channel); if (periodic) tcon |= TCON_AUTORELOAD(channel); else tcon &= ~TCON_AUTORELOAD(channel); writel_relaxed(tcon, pwm.base + REG_TCON); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static int samsung_set_next_event(unsigned long cycles, struct clock_event_device *evt) { /* * This check is needed to account for internal rounding * errors inside clockevents core, which might result in * passing cycles = 0, which in turn would not generate any * timer interrupt and hang the system. * * Another solution would be to set up the clockevent device * with min_delta = 2, but this would unnecessarily increase * the minimum sleep period. */ if (!cycles) cycles = 1; samsung_time_setup(pwm.event_id, cycles); samsung_time_start(pwm.event_id, false); return 0; }

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static int samsung_shutdown(struct clock_event_device *evt) { samsung_time_stop(pwm.event_id); return 0; }

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static int samsung_set_periodic(struct clock_event_device *evt) { samsung_time_stop(pwm.event_id); samsung_time_setup(pwm.event_id, pwm.clock_count_per_tick - 1); samsung_time_start(pwm.event_id, true); return 0; }

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static void samsung_clockevent_resume(struct clock_event_device *cev) { samsung_timer_set_prescale(pwm.event_id, pwm.tscaler_div); samsung_timer_set_divisor(pwm.event_id, pwm.tdiv); if (pwm.variant.has_tint_cstat) { u32 mask = (1 << pwm.event_id); writel(mask | (mask << 5), pwm.base + REG_TINT_CSTAT); } }

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static struct clock_event_device time_event_device = { .name = "samsung_event_timer", .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, .rating = 200, .set_next_event = samsung_set_next_event, .set_state_shutdown = samsung_shutdown, .set_state_periodic = samsung_set_periodic, .set_state_oneshot = samsung_shutdown, .tick_resume = samsung_shutdown, .resume = samsung_clockevent_resume, };
static irqreturn_t samsung_clock_event_isr(int irq, void *dev_id) { struct clock_event_device *evt = dev_id; if (pwm.variant.has_tint_cstat) { u32 mask = (1 << pwm.event_id); writel(mask | (mask << 5), pwm.base + REG_TINT_CSTAT); } evt->event_handler(evt); return IRQ_HANDLED; }

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static struct irqaction samsung_clock_event_irq = { .name = "samsung_time_irq", .flags = IRQF_TIMER | IRQF_IRQPOLL, .handler = samsung_clock_event_isr, .dev_id = &time_event_device, };
static void __init samsung_clockevent_init(void) { unsigned long pclk; unsigned long clock_rate; unsigned int irq_number; pclk = clk_get_rate(pwm.timerclk); samsung_timer_set_prescale(pwm.event_id, pwm.tscaler_div); samsung_timer_set_divisor(pwm.event_id, pwm.tdiv); clock_rate = pclk / (pwm.tscaler_div * pwm.tdiv); pwm.clock_count_per_tick = clock_rate / HZ; time_event_device.cpumask = cpumask_of(0); clockevents_config_and_register(&time_event_device, clock_rate, 1, pwm.tcnt_max); irq_number = pwm.irq[pwm.event_id]; setup_irq(irq_number, &samsung_clock_event_irq); if (pwm.variant.has_tint_cstat) { u32 mask = (1 << pwm.event_id); writel(mask | (mask << 5), pwm.base + REG_TINT_CSTAT); } }

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static void samsung_clocksource_suspend(struct clocksource *cs) { samsung_time_stop(pwm.source_id); }

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static void samsung_clocksource_resume(struct clocksource *cs) { samsung_timer_set_prescale(pwm.source_id, pwm.tscaler_div); samsung_timer_set_divisor(pwm.source_id, pwm.tdiv); samsung_time_setup(pwm.source_id, pwm.tcnt_max); samsung_time_start(pwm.source_id, true); }

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static u64 notrace samsung_clocksource_read(struct clocksource *c) { return ~readl_relaxed(pwm.source_reg); }

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static struct clocksource samsung_clocksource = { .name = "samsung_clocksource_timer", .rating = 250, .read = samsung_clocksource_read, .suspend = samsung_clocksource_suspend, .resume = samsung_clocksource_resume, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; /* * Override the global weak sched_clock symbol with this * local implementation which uses the clocksource to get some * better resolution when scheduling the kernel. We accept that * this wraps around for now, since it is just a relative time * stamp. (Inspired by U300 implementation.) */
static u64 notrace samsung_read_sched_clock(void) { return samsung_clocksource_read(NULL); }

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static int __init samsung_clocksource_init(void) { unsigned long pclk; unsigned long clock_rate; pclk = clk_get_rate(pwm.timerclk); samsung_timer_set_prescale(pwm.source_id, pwm.tscaler_div); samsung_timer_set_divisor(pwm.source_id, pwm.tdiv); clock_rate = pclk / (pwm.tscaler_div * pwm.tdiv); samsung_time_setup(pwm.source_id, pwm.tcnt_max); samsung_time_start(pwm.source_id, true); if (pwm.source_id == 4) pwm.source_reg = pwm.base + 0x40; else pwm.source_reg = pwm.base + pwm.source_id * 0x0c + 0x14; sched_clock_register(samsung_read_sched_clock, pwm.variant.bits, clock_rate); samsung_clocksource.mask = CLOCKSOURCE_MASK(pwm.variant.bits); return clocksource_register_hz(&samsung_clocksource, clock_rate); }

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static void __init samsung_timer_resources(void) { clk_prepare_enable(pwm.timerclk); pwm.tcnt_max = (1UL << pwm.variant.bits) - 1; if (pwm.variant.bits == 16) { pwm.tscaler_div = 25; pwm.tdiv = 2; } else { pwm.tscaler_div = 2; pwm.tdiv = 1; } }

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/* * PWM master driver */
static int __init _samsung_pwm_clocksource_init(void) { u8 mask; int channel; mask = ~pwm.variant.output_mask & ((1 << SAMSUNG_PWM_NUM) - 1); channel = fls(mask) - 1; if (channel < 0) { pr_crit("failed to find PWM channel for clocksource\n"); return -EINVAL; } pwm.source_id = channel; mask &= ~(1 << channel); channel = fls(mask) - 1; if (channel < 0) { pr_crit("failed to find PWM channel for clock event\n"); return -EINVAL; } pwm.event_id = channel; samsung_timer_resources(); samsung_clockevent_init(); return samsung_clocksource_init(); }

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void __init samsung_pwm_clocksource_init(void __iomem *base, unsigned int *irqs, struct samsung_pwm_variant *variant) { pwm.base = base; memcpy(&pwm.variant, variant, sizeof(pwm.variant)); memcpy(pwm.irq, irqs, SAMSUNG_PWM_NUM * sizeof(*irqs)); pwm.timerclk = clk_get(NULL, "timers"); if (IS_ERR(pwm.timerclk)) panic("failed to get timers clock for timer"); _samsung_pwm_clocksource_init(); }

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#ifdef CONFIG_TIMER_OF
static int __init samsung_pwm_alloc(struct device_node *np, const struct samsung_pwm_variant *variant) { struct property *prop; const __be32 *cur; u32 val; int i; memcpy(&pwm.variant, variant, sizeof(pwm.variant)); for (i = 0; i < SAMSUNG_PWM_NUM; ++i) pwm.irq[i] = irq_of_parse_and_map(np, i); of_property_for_each_u32(np, "samsung,pwm-outputs", prop, cur, val) { if (val >= SAMSUNG_PWM_NUM) { pr_warning("%s: invalid channel index in samsung,pwm-outputs property\n", __func__); continue; } pwm.variant.output_mask |= 1 << val; } pwm.base = of_iomap(np, 0); if (!pwm.base) { pr_err("%s: failed to map PWM registers\n", __func__); return -ENXIO; } pwm.timerclk = of_clk_get_by_name(np, "timers"); if (IS_ERR(pwm.timerclk)) { pr_crit("failed to get timers clock for timer\n"); return PTR_ERR(pwm.timerclk); } return _samsung_pwm_clocksource_init(); }

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static const struct samsung_pwm_variant s3c24xx_variant = { .bits = 16, .div_base = 1, .has_tint_cstat = false, .tclk_mask = (1 << 4), };
static int __init s3c2410_pwm_clocksource_init(struct device_node *np) { return samsung_pwm_alloc(np, &s3c24xx_variant); }

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TIMER_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 int __init s3c64xx_pwm_clocksource_init(struct device_node *np) { return samsung_pwm_alloc(np, &s3c64xx_variant); }

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Tomasz Figa1885.71%150.00%
Daniel Lezcano314.29%150.00%
Total21100.00%2100.00%

TIMER_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 int __init s5p64x0_pwm_clocksource_init(struct device_node *np) { return samsung_pwm_alloc(np, &s5p64x0_variant); }

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Tomasz Figa1885.71%150.00%
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Total21100.00%2100.00%

TIMER_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 int __init s5p_pwm_clocksource_init(struct device_node *np) { return samsung_pwm_alloc(np, &s5p_variant); }

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TIMER_OF_DECLARE(s5pc100_pwm, "samsung,s5pc100-pwm", s5p_pwm_clocksource_init); #endif

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Daniel Lezcano552.49%313.04%
Viresh Kumar421.90%14.35%
Matthew Leach80.36%14.35%
Stephen Boyd40.18%28.70%
Rafał Miłecki30.14%14.35%
Thomas Gleixner10.05%14.35%
JiSheng Zhang10.05%14.35%
Total2212100.00%23100.00%
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