1 files changed, 494 insertions, 0 deletions
diff --git a/drivers/clocksource/samsung_pwm_timer.c b/drivers/clocksource/samsung_pwm_timer.c
new file mode 100644
index 00000000000..0234c8d2c8f
--- /dev/null
+++ b/drivers/clocksource/samsung_pwm_timer.c
@@ -0,0 +1,494 @@
+/*
+ * 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 <clocksource/samsung_pwm.h>
+
+#include <asm/sched_clock.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
+
+#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_SPINLOCK(samsung_pwm_lock);
+EXPORT_SYMBOL(samsung_pwm_lock);
+
+struct samsung_pwm_clocksource {
+	void __iomem *base;
+	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 = __raw_readl(pwm.base + REG_TCON);
+	tcon &= ~TCON_START(channel);
+	__raw_writel(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 = __raw_readl(pwm.base + REG_TCON);
+
+	tcon &= ~(TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan));
+	tcon |= TCON_MANUALUPDATE(tcon_chan);
+
+	__raw_writel(tcnt, pwm.base + REG_TCNTB(channel));
+	__raw_writel(tcnt, pwm.base + REG_TCMPB(channel));
+	__raw_writel(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 = __raw_readl(pwm.base + REG_TCON);
+
+	tcon &= ~TCON_MANUALUPDATE(channel);
+	tcon |= TCON_START(channel);
+
+	if (periodic)
+		tcon |= TCON_AUTORELOAD(channel);
+	else
+		tcon &= ~TCON_AUTORELOAD(channel);
+
+	__raw_writel(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 void samsung_timer_resume(void)
+{
+	/* event timer restart */
+	samsung_time_setup(pwm.event_id, pwm.clock_count_per_tick - 1);
+	samsung_time_start(pwm.event_id, true);
+
+	/* source timer restart */
+	samsung_time_setup(pwm.source_id, pwm.tcnt_max);
+	samsung_time_start(pwm.source_id, true);
+}
+
+static void samsung_set_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt)
+{
+	samsung_time_stop(pwm.event_id);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		samsung_time_setup(pwm.event_id, pwm.clock_count_per_tick - 1);
+		samsung_time_start(pwm.event_id, true);
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+		break;
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		break;
+
+	case CLOCK_EVT_MODE_RESUME:
+		samsung_timer_resume();
+		break;
+	}
+}
+
+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_mode	= samsung_set_mode,
+};
+
+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 struct irqaction samsung_clock_event_irq = {
+	.name		= "samsung_time_irq",
+	.flags		= IRQF_DISABLED | 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);
+	}
+}
+
+static void __iomem *samsung_timer_reg(void)
+{
+	switch (pwm.source_id) {
+	case 0:
+	case 1:
+	case 2:
+	case 3:
+		return pwm.base + pwm.source_id * 0x0c + 0x14;
+
+	case 4:
+		return pwm.base + 0x40;
+
+	default:
+		BUG();
+	}
+}
+
+/*
+ * 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 u32 notrace samsung_read_sched_clock(void)
+{
+	void __iomem *reg = samsung_timer_reg();
+
+	if (!reg)
+		return 0;
+
+	return ~__raw_readl(reg);
+}
+
+static void __init samsung_clocksource_init(void)
+{
+	void __iomem *reg = samsung_timer_reg();
+	unsigned long pclk;
+	unsigned long clock_rate;
+	int ret;
+
+	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);
+
+	setup_sched_clock(samsung_read_sched_clock,
+						pwm.variant.bits, clock_rate);
+
+	ret = clocksource_mmio_init(reg, "samsung_clocksource_timer",
+					clock_rate, 250, pwm.variant.bits,
+					clocksource_mmio_readl_down);
+	if (ret)
+		panic("samsung_clocksource_timer: can't register clocksource\n");
+}
+
+static void __init samsung_timer_resources(void)
+{
+	pwm.timerclk = clk_get(NULL, "timers");
+	if (IS_ERR(pwm.timerclk))
+		panic("failed to get timers clock for timer");
+
+	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 void __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)
+		panic("failed to find PWM channel for clocksource");
+	pwm.source_id = channel;
+
+	mask &= ~(1 << channel);
+	channel = fls(mask) - 1;
+	if (channel < 0)
+		panic("failed to find PWM channel for clock event");
+	pwm.event_id = channel;
+
+	samsung_timer_resources();
+	samsung_clockevent_init();
+	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));
+
+	_samsung_pwm_clocksource_init();
+}
+
+#ifdef CONFIG_CLKSRC_OF
+static void __init samsung_pwm_alloc(struct device_node *np,
+				     const struct samsung_pwm_variant *variant)
+{
+	struct resource res;
+	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;
+	}
+
+	of_address_to_resource(np, 0, &res);
+	if (!request_mem_region(res.start,
+				resource_size(&res), "samsung-pwm")) {
+		pr_err("%s: failed to request IO mem region\n", __func__);
+		return;
+	}
+
+	pwm.base = ioremap(res.start, resource_size(&res));
+	if (!pwm.base) {
+		pr_err("%s: failed to map PWM registers\n", __func__);
+		release_mem_region(res.start, resource_size(&res));
+		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 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);
+#endif