Merge branch 'exynos/pwm-clocksource' into late/multiplatform

This series from Tomasz Figa restores support for the pwm clocksource
in Exynos, which was broken during the conversion of the platform
to the common clk framework. The clocksource is only used in one
board in the mainline kernel (universal_c210), and this makes it
work for DT based probing as well as restoring the non-DT based
case.

* exynos/pwm-clocksource:
  ARM: dts: exynops4210: really add universal_c210 dts
  ARM: dts: exynos4210: Add basic dts file for universal_c210 board
  ARM: dts: exynos4: Add node for PWM device
  ARM: SAMSUNG: Do not register legacy timer interrupts on Exynos
  clocksource: samsung_pwm_timer: Work around rounding errors in clockevents core
  clocksource: samsung_pwm_timer: Correct programming of clock events
  clocksource: samsung_pwm_timer: Use proper clockevents max_delta
  clocksource: samsung_pwm_timer: Add support for non-DT platforms
  clocksource: samsung_pwm_timer: Drop unused samsung_pwm struct
  clocksource: samsung_pwm_timer: Keep all driver data in a structure
  clocksource: samsung_pwm_timer: Make PWM spinlock global
  clocksource: samsung_pwm_timer: Let platforms select the driver
  Documentation: Add device tree bindings for Samsung PWM timers
  clocksource: add samsung pwm timer driver

Conflicts:
	arch/arm/boot/dts/Makefile
	arch/arm/mach-exynos/common.c
	drivers/clocksource/Kconfig
	drivers/clocksource/Makefile

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 504 insertions, 0 deletions

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 73fcddb8314d..5d9bab2b5012 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -75,3 +75,12 @@ config CLKSRC_EXYNOS_MCT
         def_bool y if ARCH_EXYNOS
         help
           Support for Multi Core Timer controller on Exynos SoCs.
+
+config CLKSRC_SAMSUNG_PWM
+        bool
+        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 cd1f09cbd61a..2289f0cb4c4c 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_ARCH_TEGRA)	+= tegra20_timer.o
 obj-$(CONFIG_VT8500_TIMER)      += vt8500_timer.o
 obj-$(CONFIG_CADENCE_TTC_TIMER) += cadence_ttc_timer.o
 obj-$(CONFIG_CLKSRC_EXYNOS_MCT) += exynos_mct.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..0234c8d2c8f2
--- /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