// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2011 Samsung Electronics Co., Ltd. * http://www.samsung.com/ * * samsung - Common hr-timer support (s3c and s5p) */ #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; const 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); } 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); } 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); } 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); } 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); } 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; } static int samsung_shutdown(struct clock_event_device *evt) { samsung_time_stop(pwm.event_id); return 0; } 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; } 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); } } 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; } 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]; if (request_irq(irq_number, samsung_clock_event_isr, IRQF_TIMER | IRQF_IRQPOLL, "samsung_time_irq", &time_event_device)) pr_err("%s: request_irq() failed\n", "samsung_time_irq"); if (pwm.variant.has_tint_cstat) { u32 mask = (1 << pwm.event_id); writel(mask | (mask << 5), pwm.base + REG_TINT_CSTAT); } } static void samsung_clocksource_suspend(struct clocksource *cs) { samsung_time_stop(pwm.source_id); } 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); } static u64 notrace samsung_clocksource_read(struct clocksource *c) { return ~readl_relaxed(pwm.source_reg); } 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); } 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); } 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; } } /* * 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(); } void __init samsung_pwm_clocksource_init(void __iomem *base, unsigned int *irqs, const 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(); } #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, ret; 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_warn("%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"); ret = PTR_ERR(pwm.timerclk); goto err_clk; } ret = _samsung_pwm_clocksource_init(); if (ret) goto err_clocksource; return 0; err_clocksource: clk_put(pwm.timerclk); pwm.timerclk = NULL; err_clk: iounmap(pwm.base); pwm.base = NULL; return ret; } 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); } 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); } 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); } 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); } TIMER_OF_DECLARE(s5pc100_pwm, "samsung,s5pc100-pwm", s5p_pwm_clocksource_init); #endif