ARM: integrator: move AP timer to clocksource

This moves the timer/clocksource implementation for the
Integrator/AP down to drivers/clocksource and augments the
driver a little to use CLOCKSOURCE_OF_DECLARE(). Remove
the static mapping of the timer blocks while we're at it.

Tested on the Integrator/AP.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 210 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-integrator-ap.c b/drivers/clocksource/timer-integrator-ap.c
new file mode 100644
index 000000000000..b9efd30513d5
--- /dev/null
+++ b/drivers/clocksource/timer-integrator-ap.c
@@ -0,0 +1,210 @@
+/*
+ * Integrator/AP timer driver
+ * Copyright (C) 2000-2003 Deep Blue Solutions Ltd
+ * Copyright (c) 2014, Linaro Limited
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/sched_clock.h>
+#include <asm/hardware/arm_timer.h>
+
+static void __iomem * sched_clk_base;
+
+static u64 notrace integrator_read_sched_clock(void)
+{
+        return -readl(sched_clk_base + TIMER_VALUE);
+}
+
+static void integrator_clocksource_init(unsigned long inrate,
+                                        void __iomem *base)
+{
+        u32 ctrl = TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC;
+        unsigned long rate = inrate;
+
+        if (rate >= 1500000) {
+                rate /= 16;
+                ctrl |= TIMER_CTRL_DIV16;
+        }
+
+        writel(0xffff, base + TIMER_LOAD);
+        writel(ctrl, base + TIMER_CTRL);
+
+        clocksource_mmio_init(base + TIMER_VALUE, "timer2",
+                        rate, 200, 16, clocksource_mmio_readl_down);
+
+        sched_clk_base = base;
+        sched_clock_register(integrator_read_sched_clock, 16, rate);
+}
+
+static unsigned long timer_reload;
+static void __iomem * clkevt_base;
+
+/*
+ * IRQ handler for the timer
+ */
+static irqreturn_t integrator_timer_interrupt(int irq, void *dev_id)
+{
+        struct clock_event_device *evt = dev_id;
+
+        /* clear the interrupt */
+        writel(1, clkevt_base + TIMER_INTCLR);
+
+        evt->event_handler(evt);
+
+        return IRQ_HANDLED;
+}
+
+static void clkevt_set_mode(enum clock_event_mode mode, struct clock_event_device *evt)
+{
+        u32 ctrl = readl(clkevt_base + TIMER_CTRL) & ~TIMER_CTRL_ENABLE;
+
+        /* Disable timer */
+        writel(ctrl, clkevt_base + TIMER_CTRL);
+
+        switch (mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+                /* Enable the timer and start the periodic tick */
+                writel(timer_reload, clkevt_base + TIMER_LOAD);
+                ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
+                writel(ctrl, clkevt_base + TIMER_CTRL);
+                break;
+        case CLOCK_EVT_MODE_ONESHOT:
+                /* Leave the timer disabled, .set_next_event will enable it */
+                ctrl &= ~TIMER_CTRL_PERIODIC;
+                writel(ctrl, clkevt_base + TIMER_CTRL);
+                break;
+        case CLOCK_EVT_MODE_UNUSED:
+        case CLOCK_EVT_MODE_SHUTDOWN:
+        case CLOCK_EVT_MODE_RESUME:
+        default:
+                /* Just leave in disabled state */
+                break;
+        }
+
+}
+
+static int clkevt_set_next_event(unsigned long next, struct clock_event_device *evt)
+{
+        unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
+
+        writel(ctrl & ~TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
+        writel(next, clkevt_base + TIMER_LOAD);
+        writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
+
+        return 0;
+}
+
+static struct clock_event_device integrator_clockevent = {
+        .name           = "timer1",
+        .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+        .set_mode       = clkevt_set_mode,
+        .set_next_event = clkevt_set_next_event,
+        .rating         = 300,
+};
+
+static struct irqaction integrator_timer_irq = {
+        .name           = "timer",
+        .flags          = IRQF_TIMER | IRQF_IRQPOLL,
+        .handler        = integrator_timer_interrupt,
+        .dev_id         = &integrator_clockevent,
+};
+
+static void integrator_clockevent_init(unsigned long inrate,
+                                void __iomem *base, int irq)
+{
+        unsigned long rate = inrate;
+        unsigned int ctrl = 0;
+
+        clkevt_base = base;
+        /* Calculate and program a divisor */
+        if (rate > 0x100000 * HZ) {
+                rate /= 256;
+                ctrl |= TIMER_CTRL_DIV256;
+        } else if (rate > 0x10000 * HZ) {
+                rate /= 16;
+                ctrl |= TIMER_CTRL_DIV16;
+        }
+        timer_reload = rate / HZ;
+        writel(ctrl, clkevt_base + TIMER_CTRL);
+
+        setup_irq(irq, &integrator_timer_irq);
+        clockevents_config_and_register(&integrator_clockevent,
+                                        rate,
+                                        1,
+                                        0xffffU);
+}
+
+static void __init integrator_ap_timer_init_of(struct device_node *node)
+{
+        const char *path;
+        void __iomem *base;
+        int err;
+        int irq;
+        struct clk *clk;
+        unsigned long rate;
+        struct device_node *pri_node;
+        struct device_node *sec_node;
+
+        base = of_io_request_and_map(node, 0, "integrator-timer");
+        if (!base)
+                return;
+
+        clk = of_clk_get(node, 0);
+        if (IS_ERR(clk)) {
+                pr_err("No clock for %s\n", node->name);
+                return;
+        }
+        clk_prepare_enable(clk);
+        rate = clk_get_rate(clk);
+        writel(0, base + TIMER_CTRL);
+
+        err = of_property_read_string(of_aliases,
+                                "arm,timer-primary", &path);
+        if (WARN_ON(err))
+                return;
+        pri_node = of_find_node_by_path(path);
+        err = of_property_read_string(of_aliases,
+                                "arm,timer-secondary", &path);
+        if (WARN_ON(err))
+                return;
+        sec_node = of_find_node_by_path(path);
+
+        if (node == pri_node) {
+                /* The primary timer lacks IRQ, use as clocksource */
+                integrator_clocksource_init(rate, base);
+                return;
+        }
+
+        if (node == sec_node) {
+                /* The secondary timer will drive the clock event */
+                irq = irq_of_parse_and_map(node, 0);
+                integrator_clockevent_init(rate, base, irq);
+                return;
+        }
+
+        pr_info("Timer @%p unused\n", base);
+        clk_disable_unprepare(clk);
+}
+
+CLOCKSOURCE_OF_DECLARE(integrator_ap_timer, "arm,integrator-timer",
+                       integrator_ap_timer_init_of);