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path: root/drivers/clocksource/time-armada-370-xp.c
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Diffstat (limited to 'drivers/clocksource/time-armada-370-xp.c')
-rw-r--r--drivers/clocksource/time-armada-370-xp.c369
1 files changed, 369 insertions, 0 deletions
diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
new file mode 100644
index 000000000..0c8c5e337
--- /dev/null
+++ b/drivers/clocksource/time-armada-370-xp.c
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+/*
+ * Marvell Armada 370/XP SoC timer handling.
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Lior Amsalem <alior@marvell.com>
+ * Gregory CLEMENT <gregory.clement@free-electrons.com>
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.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.
+ *
+ * Timer 0 is used as free-running clocksource, while timer 1 is
+ * used as clock_event_device.
+ *
+ * ---
+ * Clocksource driver for Armada 370 and Armada XP SoC.
+ * This driver implements one compatible string for each SoC, given
+ * each has its own characteristics:
+ *
+ * * Armada 370 has no 25 MHz fixed timer.
+ *
+ * * Armada XP cannot work properly without such 25 MHz fixed timer as
+ * doing otherwise leads to using a clocksource whose frequency varies
+ * when doing cpufreq frequency changes.
+ *
+ * See Documentation/devicetree/bindings/timer/marvell,armada-370-xp-timer.txt
+ */
+
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/cpu.h>
+#include <linux/timer.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/sched_clock.h>
+#include <linux/percpu.h>
+#include <linux/syscore_ops.h>
+
+/*
+ * Timer block registers.
+ */
+#define TIMER_CTRL_OFF 0x0000
+#define TIMER0_EN BIT(0)
+#define TIMER0_RELOAD_EN BIT(1)
+#define TIMER0_25MHZ BIT(11)
+#define TIMER0_DIV(div) ((div) << 19)
+#define TIMER1_EN BIT(2)
+#define TIMER1_RELOAD_EN BIT(3)
+#define TIMER1_25MHZ BIT(12)
+#define TIMER1_DIV(div) ((div) << 22)
+#define TIMER_EVENTS_STATUS 0x0004
+#define TIMER0_CLR_MASK (~0x1)
+#define TIMER1_CLR_MASK (~0x100)
+#define TIMER0_RELOAD_OFF 0x0010
+#define TIMER0_VAL_OFF 0x0014
+#define TIMER1_RELOAD_OFF 0x0018
+#define TIMER1_VAL_OFF 0x001c
+
+#define LCL_TIMER_EVENTS_STATUS 0x0028
+/* Global timers are connected to the coherency fabric clock, and the
+ below divider reduces their incrementing frequency. */
+#define TIMER_DIVIDER_SHIFT 5
+#define TIMER_DIVIDER (1 << TIMER_DIVIDER_SHIFT)
+
+/*
+ * SoC-specific data.
+ */
+static void __iomem *timer_base, *local_base;
+static unsigned int timer_clk;
+static bool timer25Mhz = true;
+static u32 enable_mask;
+
+/*
+ * Number of timer ticks per jiffy.
+ */
+static u32 ticks_per_jiffy;
+
+static struct clock_event_device __percpu *armada_370_xp_evt;
+
+static void local_timer_ctrl_clrset(u32 clr, u32 set)
+{
+ writel((readl(local_base + TIMER_CTRL_OFF) & ~clr) | set,
+ local_base + TIMER_CTRL_OFF);
+}
+
+static u64 notrace armada_370_xp_read_sched_clock(void)
+{
+ return ~readl(timer_base + TIMER0_VAL_OFF);
+}
+
+/*
+ * Clockevent handling.
+ */
+static int
+armada_370_xp_clkevt_next_event(unsigned long delta,
+ struct clock_event_device *dev)
+{
+ /*
+ * Clear clockevent timer interrupt.
+ */
+ writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
+
+ /*
+ * Setup new clockevent timer value.
+ */
+ writel(delta, local_base + TIMER0_VAL_OFF);
+
+ /*
+ * Enable the timer.
+ */
+ local_timer_ctrl_clrset(TIMER0_RELOAD_EN, enable_mask);
+ return 0;
+}
+
+static void
+armada_370_xp_clkevt_mode(enum clock_event_mode mode,
+ struct clock_event_device *dev)
+{
+ if (mode == CLOCK_EVT_MODE_PERIODIC) {
+
+ /*
+ * Setup timer to fire at 1/HZ intervals.
+ */
+ writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF);
+ writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF);
+
+ /*
+ * Enable timer.
+ */
+ local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | enable_mask);
+ } else {
+ /*
+ * Disable timer.
+ */
+ local_timer_ctrl_clrset(TIMER0_EN, 0);
+
+ /*
+ * ACK pending timer interrupt.
+ */
+ writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
+ }
+}
+
+static int armada_370_xp_clkevt_irq;
+
+static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
+{
+ /*
+ * ACK timer interrupt and call event handler.
+ */
+ struct clock_event_device *evt = dev_id;
+
+ writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Setup the local clock events for a CPU.
+ */
+static int armada_370_xp_timer_setup(struct clock_event_device *evt)
+{
+ u32 clr = 0, set = 0;
+ int cpu = smp_processor_id();
+
+ if (timer25Mhz)
+ set = TIMER0_25MHZ;
+ else
+ clr = TIMER0_25MHZ;
+ local_timer_ctrl_clrset(clr, set);
+
+ evt->name = "armada_370_xp_per_cpu_tick",
+ evt->features = CLOCK_EVT_FEAT_ONESHOT |
+ CLOCK_EVT_FEAT_PERIODIC;
+ evt->shift = 32,
+ evt->rating = 300,
+ evt->set_next_event = armada_370_xp_clkevt_next_event,
+ evt->set_mode = armada_370_xp_clkevt_mode,
+ evt->irq = armada_370_xp_clkevt_irq;
+ evt->cpumask = cpumask_of(cpu);
+
+ clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe);
+ enable_percpu_irq(evt->irq, 0);
+
+ return 0;
+}
+
+static void armada_370_xp_timer_stop(struct clock_event_device *evt)
+{
+ evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
+ disable_percpu_irq(evt->irq);
+}
+
+static int armada_370_xp_timer_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ /*
+ * Grab cpu pointer in each case to avoid spurious
+ * preemptible warnings
+ */
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_STARTING:
+ armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt));
+ break;
+ case CPU_DYING:
+ armada_370_xp_timer_stop(this_cpu_ptr(armada_370_xp_evt));
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block armada_370_xp_timer_cpu_nb = {
+ .notifier_call = armada_370_xp_timer_cpu_notify,
+};
+
+static u32 timer0_ctrl_reg, timer0_local_ctrl_reg;
+
+static int armada_370_xp_timer_suspend(void)
+{
+ timer0_ctrl_reg = readl(timer_base + TIMER_CTRL_OFF);
+ timer0_local_ctrl_reg = readl(local_base + TIMER_CTRL_OFF);
+ return 0;
+}
+
+static void armada_370_xp_timer_resume(void)
+{
+ writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
+ writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
+ writel(timer0_ctrl_reg, timer_base + TIMER_CTRL_OFF);
+ writel(timer0_local_ctrl_reg, local_base + TIMER_CTRL_OFF);
+}
+
+struct syscore_ops armada_370_xp_timer_syscore_ops = {
+ .suspend = armada_370_xp_timer_suspend,
+ .resume = armada_370_xp_timer_resume,
+};
+
+static void __init armada_370_xp_timer_common_init(struct device_node *np)
+{
+ u32 clr = 0, set = 0;
+ int res;
+
+ timer_base = of_iomap(np, 0);
+ WARN_ON(!timer_base);
+ local_base = of_iomap(np, 1);
+
+ if (timer25Mhz) {
+ set = TIMER0_25MHZ;
+ enable_mask = TIMER0_EN;
+ } else {
+ clr = TIMER0_25MHZ;
+ enable_mask = TIMER0_EN | TIMER0_DIV(TIMER_DIVIDER_SHIFT);
+ }
+ atomic_io_modify(timer_base + TIMER_CTRL_OFF, clr | set, set);
+ local_timer_ctrl_clrset(clr, set);
+
+ /*
+ * We use timer 0 as clocksource, and private(local) timer 0
+ * for clockevents
+ */
+ armada_370_xp_clkevt_irq = irq_of_parse_and_map(np, 4);
+
+ ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
+
+ /*
+ * Setup free-running clocksource timer (interrupts
+ * disabled).
+ */
+ writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
+ writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
+
+ atomic_io_modify(timer_base + TIMER_CTRL_OFF,
+ TIMER0_RELOAD_EN | enable_mask,
+ TIMER0_RELOAD_EN | enable_mask);
+
+ /*
+ * Set scale and timer for sched_clock.
+ */
+ sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
+
+ clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
+ "armada_370_xp_clocksource",
+ timer_clk, 300, 32, clocksource_mmio_readl_down);
+
+ register_cpu_notifier(&armada_370_xp_timer_cpu_nb);
+
+ armada_370_xp_evt = alloc_percpu(struct clock_event_device);
+
+
+ /*
+ * Setup clockevent timer (interrupt-driven).
+ */
+ res = request_percpu_irq(armada_370_xp_clkevt_irq,
+ armada_370_xp_timer_interrupt,
+ "armada_370_xp_per_cpu_tick",
+ armada_370_xp_evt);
+ /* Immediately configure the timer on the boot CPU */
+ if (!res)
+ armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt));
+
+ register_syscore_ops(&armada_370_xp_timer_syscore_ops);
+}
+
+static void __init armada_xp_timer_init(struct device_node *np)
+{
+ struct clk *clk = of_clk_get_by_name(np, "fixed");
+
+ /* The 25Mhz fixed clock is mandatory, and must always be available */
+ BUG_ON(IS_ERR(clk));
+ clk_prepare_enable(clk);
+ timer_clk = clk_get_rate(clk);
+
+ armada_370_xp_timer_common_init(np);
+}
+CLOCKSOURCE_OF_DECLARE(armada_xp, "marvell,armada-xp-timer",
+ armada_xp_timer_init);
+
+static void __init armada_375_timer_init(struct device_node *np)
+{
+ struct clk *clk;
+
+ clk = of_clk_get_by_name(np, "fixed");
+ if (!IS_ERR(clk)) {
+ clk_prepare_enable(clk);
+ timer_clk = clk_get_rate(clk);
+ } else {
+
+ /*
+ * This fallback is required in order to retain proper
+ * devicetree backwards compatibility.
+ */
+ clk = of_clk_get(np, 0);
+
+ /* Must have at least a clock */
+ BUG_ON(IS_ERR(clk));
+ clk_prepare_enable(clk);
+ timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
+ timer25Mhz = false;
+ }
+
+ armada_370_xp_timer_common_init(np);
+}
+CLOCKSOURCE_OF_DECLARE(armada_375, "marvell,armada-375-timer",
+ armada_375_timer_init);
+
+static void __init armada_370_timer_init(struct device_node *np)
+{
+ struct clk *clk = of_clk_get(np, 0);
+
+ BUG_ON(IS_ERR(clk));
+ clk_prepare_enable(clk);
+ timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
+ timer25Mhz = false;
+
+ armada_370_xp_timer_common_init(np);
+}
+CLOCKSOURCE_OF_DECLARE(armada_370, "marvell,armada-370-timer",
+ armada_370_timer_init);