4 files changed, 529 insertions, 0 deletions

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index e507ab7df60b..03caba2540e2 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -67,3 +67,13 @@ config CLKSRC_METAG_GENERIC
         def_bool y if METAG
         help
           This option enables support for the Meta per-thread timers.
+
+config CLKSRC_SAMSUNG_PWM
+        def_bool ARCH_EXYNOS4
+        depends on OF
+        select CLKSRC_MMIO
+        help
+          This is a new clocksource driver for the PWM timer found in
+          Samsung S3C, S5P and Exynos SoCs, replacing an earlier driver
+          for all devicetree enabled platforms. This driver will be
+          needed only on systems that do not have the Exynos MCT available.
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 4d8283aec5b5..891c9f2af021 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835_timer.o
 obj-$(CONFIG_SUNXI_TIMER)       += sunxi_timer.o
 obj-$(CONFIG_ARCH_TEGRA)        += tegra20_timer.o
 obj-$(CONFIG_VT8500_TIMER)      += vt8500_timer.o
+obj-$(CONFIG_CLKSRC_SAMSUNG_PWM)        += samsung_pwm_timer.o
 
 obj-$(CONFIG_ARM_ARCH_TIMER)            += arm_arch_timer.o
 obj-$(CONFIG_CLKSRC_METAG_GENERIC)      += metag_generic.o
diff --git a/drivers/clocksource/samsung_pwm_timer.c b/drivers/clocksource/samsung_pwm_timer.c
new file mode 100644
index 000000000000..1752457a4f76
--- /dev/null
+++ b/drivers/clocksource/samsung_pwm_timer.c
@@ -0,0 +1,477 @@
+/*
+ * 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))
+
+struct samsung_timer_source {
+        unsigned int event_id;
+        unsigned int source_id;
+        unsigned int tcnt_max;
+        unsigned int tscaler_div;
+        unsigned int tdiv;
+};
+
+static struct samsung_pwm *pwm;
+static struct clk *timerclk;
+static struct samsung_timer_source timer_source;
+static unsigned long clock_count_per_tick;
+
+static void samsung_timer_set_prescale(struct samsung_pwm *pwm,
+                                        unsigned int channel, u16 prescale)
+{
+        unsigned long flags;
+        u8 shift = 0;
+        u32 reg;
+
+        if (channel >= 2)
+                shift = TCFG0_PRESCALER1_SHIFT;
+
+        spin_lock_irqsave(&pwm->slock, 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(&pwm->slock, flags);
+}
+
+static void samsung_timer_set_divisor(struct samsung_pwm *pwm,
+                                        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(&pwm->slock, flags);
+
+        reg = readl(pwm->base + REG_TCFG1);
+        reg &= ~(TCFG1_MUX_MASK << shift);
+        reg |= bits << shift;
+        writel(reg, pwm->base + REG_TCFG1);
+
+        spin_unlock_irqrestore(&pwm->slock, flags);
+}
+
+static void samsung_time_stop(unsigned int channel)
+{
+        unsigned long tcon;
+        unsigned long flags;
+
+        if (channel > 0)
+                ++channel;
+
+        spin_lock_irqsave(&pwm->slock, flags);
+
+        tcon = __raw_readl(pwm->base + REG_TCON);
+        tcon &= ~TCON_START(channel);
+        __raw_writel(tcon, pwm->base + REG_TCON);
+
+        spin_unlock_irqrestore(&pwm->slock, 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(&pwm->slock, flags);
+
+        tcon = __raw_readl(pwm->base + REG_TCON);
+
+        tcnt--;
+
+        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(&pwm->slock, flags);
+}
+
+static void samsung_time_start(unsigned int channel, bool periodic)
+{
+        unsigned long tcon;
+        unsigned long flags;
+
+        if (channel > 0)
+                ++channel;
+
+        spin_lock_irqsave(&pwm->slock, 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(&pwm->slock, flags);
+}
+
+static int samsung_set_next_event(unsigned long cycles,
+                                struct clock_event_device *evt)
+{
+        samsung_time_setup(timer_source.event_id, cycles);
+        samsung_time_start(timer_source.event_id, false);
+
+        return 0;
+}
+
+static void samsung_timer_resume(void)
+{
+        /* event timer restart */
+        samsung_time_setup(timer_source.event_id, clock_count_per_tick);
+        samsung_time_start(timer_source.event_id, true);
+
+        /* source timer restart */
+        samsung_time_setup(timer_source.source_id, timer_source.tcnt_max);
+        samsung_time_start(timer_source.source_id, true);
+}
+
+static void samsung_set_mode(enum clock_event_mode mode,
+                                struct clock_event_device *evt)
+{
+        samsung_time_stop(timer_source.event_id);
+
+        switch (mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+                samsung_time_setup(timer_source.event_id, clock_count_per_tick);
+                samsung_time_start(timer_source.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 << timer_source.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(timerclk);
+
+        samsung_timer_set_prescale(pwm, timer_source.event_id,
+                                                timer_source.tscaler_div);
+        samsung_timer_set_divisor(pwm, timer_source.event_id,
+                                                timer_source.tdiv);
+
+        clock_rate = pclk / (timer_source.tscaler_div * timer_source.tdiv);
+        clock_count_per_tick = clock_rate / HZ;
+
+        time_event_device.cpumask = cpumask_of(0);
+        clockevents_config_and_register(&time_event_device, clock_rate, 1, -1);
+
+        irq_number = pwm->irq[timer_source.event_id];
+        setup_irq(irq_number, &samsung_clock_event_irq);
+
+        if (pwm->variant.has_tint_cstat) {
+                u32 mask = (1 << timer_source.event_id);
+                writel(mask | (mask << 5), pwm->base + REG_TINT_CSTAT);
+        }
+}
+
+static void __iomem *samsung_timer_reg(void)
+{
+        switch (timer_source.source_id) {
+        case 0:
+        case 1:
+        case 2:
+        case 3:
+                return pwm->base + timer_source.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(timerclk);
+
+        samsung_timer_set_prescale(pwm, timer_source.source_id,
+                                                timer_source.tscaler_div);
+        samsung_timer_set_divisor(pwm, timer_source.source_id,
+                                                timer_source.tdiv);
+
+        clock_rate = pclk / (timer_source.tscaler_div * timer_source.tdiv);
+
+        samsung_time_setup(timer_source.source_id, timer_source.tcnt_max);
+        samsung_time_start(timer_source.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)
+{
+        timerclk = clk_get(NULL, "timers");
+        if (IS_ERR(timerclk))
+                panic("failed to get timers clock for timer");
+
+        clk_prepare_enable(timerclk);
+
+        timer_source.tcnt_max = (1UL << pwm->variant.bits) - 1;
+        if (pwm->variant.bits == 16) {
+                timer_source.tscaler_div = 25;
+                timer_source.tdiv = 2;
+        } else {
+                timer_source.tscaler_div = 2;
+                timer_source.tdiv = 1;
+        }
+}
+
+/*
+ * PWM master driver
+ */
+static void __init samsung_pwm_clocksource_init(void)
+{
+        u8 mask;
+        int channel;
+
+        if (!pwm)
+                panic("no pwm clocksource device found");
+
+        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");
+        timer_source.source_id = channel;
+
+        mask &= ~(1 << channel);
+        channel = fls(mask) - 1;
+        if (channel < 0)
+                panic("failed to find PWM channel for clock event");
+        timer_source.event_id = channel;
+
+        samsung_timer_resources();
+        samsung_clockevent_init();
+        samsung_clocksource_init();
+}
+
+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;
+
+        pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
+        if (!pwm) {
+                pr_err("%s: could not allocate PWM device struct\n", __func__);
+                return;
+        }
+        memcpy(&pwm->variant, variant, sizeof(pwm->variant));
+        spin_lock_init(&pwm->slock);
+        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);
diff --git a/include/clocksource/samsung_pwm.h b/include/clocksource/samsung_pwm.h
new file mode 100644
index 000000000000..eff8668da252
--- /dev/null
+++ b/include/clocksource/samsung_pwm.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2013 Samsung Electronics Co., Ltd.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __CLOCKSOURCE_SAMSUNG_PWM_H
+#define __CLOCKSOURCE_SAMSUNG_PWM_H
+
+#include <linux/spinlock.h>
+
+#define SAMSUNG_PWM_NUM         5
+
+struct platform_device;
+struct device_node;
+
+struct samsung_pwm_variant {
+        u8 bits;
+        u8 div_base;
+        u8 tclk_mask;
+        u8 output_mask;
+        bool has_tint_cstat;
+};
+
+struct samsung_pwm {
+        struct samsung_pwm_variant variant;
+        spinlock_t slock;
+        void __iomem *base;
+        int irq[SAMSUNG_PWM_NUM];
+};
+
+#endif /* __CLOCKSOURCE_SAMSUNG_PWM_H */