1 files changed, 220 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-sun4i.c b/drivers/clocksource/timer-sun4i.c
new file mode 100644
index 000000000000..6e0180aaf784
--- /dev/null
+++ b/drivers/clocksource/timer-sun4i.c
@@ -0,0 +1,220 @@
+/*
+ * Allwinner A1X SoCs timer handling.
+ *
+ * Copyright (C) 2012 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * Based on code from
+ * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
+ * Benn Huang <benn@allwinnertech.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqreturn.h>
+#include <linux/sched_clock.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include "timer-of.h"
+
+#define TIMER_IRQ_EN_REG        0x00
+#define TIMER_IRQ_EN(val)               BIT(val)
+#define TIMER_IRQ_ST_REG        0x04
+#define TIMER_CTL_REG(val)      (0x10 * val + 0x10)
+#define TIMER_CTL_ENABLE                BIT(0)
+#define TIMER_CTL_RELOAD                BIT(1)
+#define TIMER_CTL_CLK_SRC(val)          (((val) & 0x3) << 2)
+#define TIMER_CTL_CLK_SRC_OSC24M                (1)
+#define TIMER_CTL_CLK_PRES(val)         (((val) & 0x7) << 4)
+#define TIMER_CTL_ONESHOT               BIT(7)
+#define TIMER_INTVAL_REG(val)   (0x10 * (val) + 0x14)
+#define TIMER_CNTVAL_REG(val)   (0x10 * (val) + 0x18)
+
+#define TIMER_SYNC_TICKS        3
+
+/*
+ * When we disable a timer, we need to wait at least for 2 cycles of
+ * the timer source clock. We will use for that the clocksource timer
+ * that is already setup and runs at the same frequency than the other
+ * timers, and we never will be disabled.
+ */
+static void sun4i_clkevt_sync(void __iomem *base)
+{
+        u32 old = readl(base + TIMER_CNTVAL_REG(1));
+
+        while ((old - readl(base + TIMER_CNTVAL_REG(1))) < TIMER_SYNC_TICKS)
+                cpu_relax();
+}
+
+static void sun4i_clkevt_time_stop(void __iomem *base, u8 timer)
+{
+        u32 val = readl(base + TIMER_CTL_REG(timer));
+        writel(val & ~TIMER_CTL_ENABLE, base + TIMER_CTL_REG(timer));
+        sun4i_clkevt_sync(base);
+}
+
+static void sun4i_clkevt_time_setup(void __iomem *base, u8 timer,
+                                    unsigned long delay)
+{
+        writel(delay, base + TIMER_INTVAL_REG(timer));
+}
+
+static void sun4i_clkevt_time_start(void __iomem *base, u8 timer,
+                                    bool periodic)
+{
+        u32 val = readl(base + TIMER_CTL_REG(timer));
+
+        if (periodic)
+                val &= ~TIMER_CTL_ONESHOT;
+        else
+                val |= TIMER_CTL_ONESHOT;
+
+        writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
+               base + TIMER_CTL_REG(timer));
+}
+
+static int sun4i_clkevt_shutdown(struct clock_event_device *evt)
+{
+        struct timer_of *to = to_timer_of(evt);
+
+        sun4i_clkevt_time_stop(timer_of_base(to), 0);
+
+        return 0;
+}
+
+static int sun4i_clkevt_set_oneshot(struct clock_event_device *evt)
+{
+        struct timer_of *to = to_timer_of(evt);
+
+        sun4i_clkevt_time_stop(timer_of_base(to), 0);
+        sun4i_clkevt_time_start(timer_of_base(to), 0, false);
+
+        return 0;
+}
+
+static int sun4i_clkevt_set_periodic(struct clock_event_device *evt)
+{
+        struct timer_of *to = to_timer_of(evt);
+
+        sun4i_clkevt_time_stop(timer_of_base(to), 0);
+        sun4i_clkevt_time_setup(timer_of_base(to), 0, timer_of_period(to));
+        sun4i_clkevt_time_start(timer_of_base(to), 0, true);
+
+        return 0;
+}
+
+static int sun4i_clkevt_next_event(unsigned long evt,
+                                   struct clock_event_device *clkevt)
+{
+        struct timer_of *to = to_timer_of(clkevt);
+
+        sun4i_clkevt_time_stop(timer_of_base(to), 0);
+        sun4i_clkevt_time_setup(timer_of_base(to), 0, evt - TIMER_SYNC_TICKS);
+        sun4i_clkevt_time_start(timer_of_base(to), 0, false);
+
+        return 0;
+}
+
+static void sun4i_timer_clear_interrupt(void __iomem *base)
+{
+        writel(TIMER_IRQ_EN(0), base + TIMER_IRQ_ST_REG);
+}
+
+static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id)
+{
+        struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+        struct timer_of *to = to_timer_of(evt);
+
+        sun4i_timer_clear_interrupt(timer_of_base(to));
+        evt->event_handler(evt);
+
+        return IRQ_HANDLED;
+}
+
+static struct timer_of to = {
+        .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
+
+        .clkevt = {
+                .name = "sun4i_tick",
+                .rating = 350,
+                .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+                .set_state_shutdown = sun4i_clkevt_shutdown,
+                .set_state_periodic = sun4i_clkevt_set_periodic,
+                .set_state_oneshot = sun4i_clkevt_set_oneshot,
+                .tick_resume = sun4i_clkevt_shutdown,
+                .set_next_event = sun4i_clkevt_next_event,
+                .cpumask = cpu_possible_mask,
+        },
+
+        .of_irq = {
+                .handler = sun4i_timer_interrupt,
+                .flags = IRQF_TIMER | IRQF_IRQPOLL,
+        },
+};
+
+static u64 notrace sun4i_timer_sched_read(void)
+{
+        return ~readl(timer_of_base(&to) + TIMER_CNTVAL_REG(1));
+}
+
+static int __init sun4i_timer_init(struct device_node *node)
+{
+        int ret;
+        u32 val;
+
+        ret = timer_of_init(node, &to);
+        if (ret)
+                return ret;
+
+        writel(~0, timer_of_base(&to) + TIMER_INTVAL_REG(1));
+        writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD |
+               TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
+               timer_of_base(&to) + TIMER_CTL_REG(1));
+
+        /*
+         * sched_clock_register does not have priorities, and on sun6i and
+         * later there is a better sched_clock registered by arm_arch_timer.c
+         */
+        if (of_machine_is_compatible("allwinner,sun4i-a10") ||
+            of_machine_is_compatible("allwinner,sun5i-a13") ||
+            of_machine_is_compatible("allwinner,sun5i-a10s"))
+                sched_clock_register(sun4i_timer_sched_read, 32,
+                                     timer_of_rate(&to));
+
+        ret = clocksource_mmio_init(timer_of_base(&to) + TIMER_CNTVAL_REG(1),
+                                    node->name, timer_of_rate(&to), 350, 32,
+                                    clocksource_mmio_readl_down);
+        if (ret) {
+                pr_err("Failed to register clocksource\n");
+                return ret;
+        }
+
+        writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
+               timer_of_base(&to) + TIMER_CTL_REG(0));
+
+        /* Make sure timer is stopped before playing with interrupts */
+        sun4i_clkevt_time_stop(timer_of_base(&to), 0);
+
+        /* clear timer0 interrupt */
+        sun4i_timer_clear_interrupt(timer_of_base(&to));
+
+        clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
+                                        TIMER_SYNC_TICKS, 0xffffffff);
+
+        /* Enable timer0 interrupt */
+        val = readl(timer_of_base(&to) + TIMER_IRQ_EN_REG);
+        writel(val | TIMER_IRQ_EN(0), timer_of_base(&to) + TIMER_IRQ_EN_REG);
+
+        return ret;
+}
+TIMER_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer",
+                       sun4i_timer_init);