2 files changed, 212 insertions, 0 deletions

diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 98f220a7a92c..4897f243a000 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_ARCH_MXS)		+= mxs_timer.o
 obj-$(CONFIG_SUN4I_TIMER)       += sun4i_timer.o
 obj-$(CONFIG_ARCH_TEGRA)        += tegra20_timer.o
 obj-$(CONFIG_VT8500_TIMER)      += vt8500_timer.o
+obj-$(CONFIG_ARCH_BCM)          += bcm_kona_timer.o
 
 obj-$(CONFIG_ARM_ARCH_TIMER)            += arm_arch_timer.o
 obj-$(CONFIG_CLKSRC_METAG_GENERIC)      += metag_generic.o
diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c
new file mode 100644
index 000000000000..350f49356458
--- /dev/null
+++ b/drivers/clocksource/bcm_kona_timer.c
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2012 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/clockchips.h>
+#include <linux/types.h>
+
+#include <linux/io.h>
+#include <asm/mach/time.h>
+
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+
+#define KONA_GPTIMER_STCS_OFFSET                        0x00000000
+#define KONA_GPTIMER_STCLO_OFFSET                       0x00000004
+#define KONA_GPTIMER_STCHI_OFFSET                       0x00000008
+#define KONA_GPTIMER_STCM0_OFFSET                       0x0000000C
+
+#define KONA_GPTIMER_STCS_TIMER_MATCH_SHIFT             0
+#define KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT          4
+
+struct kona_bcm_timers {
+        int tmr_irq;
+        void __iomem *tmr_regs;
+};
+
+static struct kona_bcm_timers timers;
+
+static u32 arch_timer_rate;
+
+/*
+ * We use the peripheral timers for system tick, the cpu global timer for
+ * profile tick
+ */
+static void kona_timer_disable_and_clear(void __iomem *base)
+{
+        uint32_t reg;
+
+        /*
+         * clear and disable interrupts
+         * We are using compare/match register 0 for our system interrupts
+         */
+        reg = readl(base + KONA_GPTIMER_STCS_OFFSET);
+
+        /* Clear compare (0) interrupt */
+        reg |= 1 << KONA_GPTIMER_STCS_TIMER_MATCH_SHIFT;
+        /* disable compare */
+        reg &= ~(1 << KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT);
+
+        writel(reg, base + KONA_GPTIMER_STCS_OFFSET);
+
+}
+
+static void
+kona_timer_get_counter(void *timer_base, uint32_t *msw, uint32_t *lsw)
+{
+        void __iomem *base = IOMEM(timer_base);
+        int loop_limit = 4;
+
+        /*
+         * Read 64-bit free running counter
+         * 1. Read hi-word
+         * 2. Read low-word
+         * 3. Read hi-word again
+         * 4.1
+         *      if new hi-word is not equal to previously read hi-word, then
+         *      start from #1
+         * 4.2
+         *      if new hi-word is equal to previously read hi-word then stop.
+         */
+
+        while (--loop_limit) {
+                *msw = readl(base + KONA_GPTIMER_STCHI_OFFSET);
+                *lsw = readl(base + KONA_GPTIMER_STCLO_OFFSET);
+                if (*msw == readl(base + KONA_GPTIMER_STCHI_OFFSET))
+                        break;
+        }
+        if (!loop_limit) {
+                pr_err("bcm_kona_timer: getting counter failed.\n");
+                pr_err(" Timer will be impacted\n");
+        }
+
+        return;
+}
+
+static const struct of_device_id bcm_timer_ids[] __initconst = {
+        {.compatible = "bcm,kona-timer"},
+        {},
+};
+
+static void __init kona_timers_init(void)
+{
+        struct device_node *node;
+        u32 freq;
+
+        node = of_find_matching_node(NULL, bcm_timer_ids);
+
+        if (!node)
+                panic("No timer");
+
+        if (!of_property_read_u32(node, "clock-frequency", &freq))
+                arch_timer_rate = freq;
+        else
+                panic("clock-frequency not set in the .dts file");
+
+        /* Setup IRQ numbers */
+        timers.tmr_irq = irq_of_parse_and_map(node, 0);
+
+        /* Setup IO addresses */
+        timers.tmr_regs = of_iomap(node, 0);
+
+        kona_timer_disable_and_clear(timers.tmr_regs);
+}
+
+static int kona_timer_set_next_event(unsigned long clc,
+                                  struct clock_event_device *unused)
+{
+        /*
+         * timer (0) is disabled by the timer interrupt already
+         * so, here we reload the next event value and re-enable
+         * the timer.
+         *
+         * This way, we are potentially losing the time between
+         * timer-interrupt->set_next_event. CPU local timers, when
+         * they come in should get rid of skew.
+         */
+
+        uint32_t lsw, msw;
+        uint32_t reg;
+
+        kona_timer_get_counter(timers.tmr_regs, &msw, &lsw);
+
+        /* Load the "next" event tick value */
+        writel(lsw + clc, timers.tmr_regs + KONA_GPTIMER_STCM0_OFFSET);
+
+        /* Enable compare */
+        reg = readl(timers.tmr_regs + KONA_GPTIMER_STCS_OFFSET);
+        reg |= (1 << KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT);
+        writel(reg, timers.tmr_regs + KONA_GPTIMER_STCS_OFFSET);
+
+        return 0;
+}
+
+static void kona_timer_set_mode(enum clock_event_mode mode,
+                             struct clock_event_device *unused)
+{
+        switch (mode) {
+        case CLOCK_EVT_MODE_ONESHOT:
+                /* by default mode is one shot don't do any thing */
+                break;
+        case CLOCK_EVT_MODE_UNUSED:
+        case CLOCK_EVT_MODE_SHUTDOWN:
+        default:
+                kona_timer_disable_and_clear(timers.tmr_regs);
+        }
+}
+
+static struct clock_event_device kona_clockevent_timer = {
+        .name = "timer 1",
+        .features = CLOCK_EVT_FEAT_ONESHOT,
+        .set_next_event = kona_timer_set_next_event,
+        .set_mode = kona_timer_set_mode
+};
+
+static void __init kona_timer_clockevents_init(void)
+{
+        kona_clockevent_timer.cpumask = cpumask_of(0);
+        clockevents_config_and_register(&kona_clockevent_timer,
+                arch_timer_rate, 6, 0xffffffff);
+}
+
+static irqreturn_t kona_timer_interrupt(int irq, void *dev_id)
+{
+        struct clock_event_device *evt = &kona_clockevent_timer;
+
+        kona_timer_disable_and_clear(timers.tmr_regs);
+        evt->event_handler(evt);
+        return IRQ_HANDLED;
+}
+
+static struct irqaction kona_timer_irq = {
+        .name = "Kona Timer Tick",
+        .flags = IRQF_TIMER,
+        .handler = kona_timer_interrupt,
+};
+
+static void __init kona_timer_init(void)
+{
+        kona_timers_init();
+        kona_timer_clockevents_init();
+        setup_irq(timers.tmr_irq, &kona_timer_irq);
+        kona_timer_set_next_event((arch_timer_rate / HZ), NULL);
+}
+
+CLOCKSOURCE_OF_DECLARE(bcm_kona, "bcm,kona-timer",
+        kona_timer_init);