--- /dev/null
+/*
+ * 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);
+}
+
+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_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:
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
+}
+
+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_mode = samsung_set_mode,
+ .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 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);
+ }
+}
+
+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 cycle_t 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 void __init samsung_clocksource_init(void)
+{
+ 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);
+
+ 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);
+ ret = clocksource_register_hz(&samsung_clocksource, clock_rate);
+ if (ret)
+ panic("samsung_clocksource_timer: can't register clocksource\n");
+}
+
+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 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));
+
+ 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_CLKSRC_OF
+static void __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;
+ }
+
+ pwm.timerclk = of_clk_get_by_name(np, "timers");
+ if (IS_ERR(pwm.timerclk))
+ panic("failed to get timers clock for timer");
+
+ _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
Code Review / kvmfornfv.git / blobdiff