1 files changed, 501 insertions, 0 deletions
diff --git a/drivers/clocksource/samsung_pwm_timer.c b/drivers/clocksource/samsung_pwm_timer.c
new file mode 100644
index 000000000..f760229d0
--- /dev/null
+++ b/drivers/clocksource/samsung_pwm_timer.c
@@ -0,0 +1,501 @@
+// 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;
+	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, 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;
+
+	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");
+		return PTR_ERR(pwm.timerclk);
+	}
+
+	return _samsung_pwm_clocksource_init();
+}
+
+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