clocksource: sunxi: Add Allwinner A1X Timer Driver
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: John Stultz <johnstul@us.ibm.com>
diff --git a/drivers/clocksource/sunxi_timer.c b/drivers/clocksource/sunxi_timer.c
new file mode 100644
index 0000000..3c46434
--- /dev/null
+++ b/drivers/clocksource/sunxi_timer.c
@@ -0,0 +1,170 @@
+/*
+ * 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/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sunxi_timer.h>
+#include <linux/clk/sunxi.h>
+
+#define TIMER_CTL_REG 0x00
+#define TIMER_CTL_ENABLE (1 << 0)
+#define TIMER_IRQ_ST_REG 0x04
+#define TIMER0_CTL_REG 0x10
+#define TIMER0_CTL_ENABLE (1 << 0)
+#define TIMER0_CTL_AUTORELOAD (1 << 1)
+#define TIMER0_CTL_ONESHOT (1 << 7)
+#define TIMER0_INTVAL_REG 0x14
+#define TIMER0_CNTVAL_REG 0x18
+
+#define TIMER_SCAL 16
+
+static void __iomem *timer_base;
+
+static void sunxi_clkevt_mode(enum clock_event_mode mode,
+ struct clock_event_device *clk)
+{
+ u32 u = readl(timer_base + TIMER0_CTL_REG);
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ u &= ~(TIMER0_CTL_ONESHOT);
+ writel(u | TIMER0_CTL_ENABLE, timer_base + TIMER0_CTL_REG);
+ break;
+
+ case CLOCK_EVT_MODE_ONESHOT:
+ writel(u | TIMER0_CTL_ONESHOT, timer_base + TIMER0_CTL_REG);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ default:
+ writel(u & ~(TIMER0_CTL_ENABLE), timer_base + TIMER0_CTL_REG);
+ break;
+ }
+}
+
+static int sunxi_clkevt_next_event(unsigned long evt,
+ struct clock_event_device *unused)
+{
+ u32 u = readl(timer_base + TIMER0_CTL_REG);
+ writel(evt, timer_base + TIMER0_CNTVAL_REG);
+ writel(u | TIMER0_CTL_ENABLE | TIMER0_CTL_AUTORELOAD,
+ timer_base + TIMER0_CTL_REG);
+
+ return 0;
+}
+
+static struct clock_event_device sunxi_clockevent = {
+ .name = "sunxi_tick",
+ .shift = 32,
+ .rating = 300,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_mode = sunxi_clkevt_mode,
+ .set_next_event = sunxi_clkevt_next_event,
+};
+
+
+static irqreturn_t sunxi_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+
+ writel(0x1, timer_base + TIMER_IRQ_ST_REG);
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction sunxi_timer_irq = {
+ .name = "sunxi_timer0",
+ .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = sunxi_timer_interrupt,
+ .dev_id = &sunxi_clockevent,
+};
+
+static struct of_device_id sunxi_timer_dt_ids[] = {
+ { .compatible = "allwinner,sunxi-timer" },
+};
+
+static void __init sunxi_timer_init(void)
+{
+ struct device_node *node;
+ unsigned long rate = 0;
+ struct clk *clk;
+ int ret, irq;
+ u32 val;
+
+ node = of_find_matching_node(NULL, sunxi_timer_dt_ids);
+ if (!node)
+ panic("No sunxi timer node");
+
+ timer_base = of_iomap(node, 0);
+ if (!timer_base)
+ panic("Can't map registers");
+
+ irq = irq_of_parse_and_map(node, 0);
+ if (irq <= 0)
+ panic("Can't parse IRQ");
+
+ sunxi_init_clocks();
+
+ clk = of_clk_get(node, 0);
+ if (IS_ERR(clk))
+ panic("Can't get timer clock");
+
+ rate = clk_get_rate(clk);
+
+ writel(rate / (TIMER_SCAL * HZ),
+ timer_base + TIMER0_INTVAL_REG);
+
+ /* set clock source to HOSC, 16 pre-division */
+ val = readl(timer_base + TIMER0_CTL_REG);
+ val &= ~(0x07 << 4);
+ val &= ~(0x03 << 2);
+ val |= (4 << 4) | (1 << 2);
+ writel(val, timer_base + TIMER0_CTL_REG);
+
+ /* set mode to auto reload */
+ val = readl(timer_base + TIMER0_CTL_REG);
+ writel(val | TIMER0_CTL_AUTORELOAD, timer_base + TIMER0_CTL_REG);
+
+ ret = setup_irq(irq, &sunxi_timer_irq);
+ if (ret)
+ pr_warn("failed to setup irq %d\n", irq);
+
+ /* Enable timer0 interrupt */
+ val = readl(timer_base + TIMER_CTL_REG);
+ writel(val | TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG);
+
+ sunxi_clockevent.mult = div_sc(rate / TIMER_SCAL,
+ NSEC_PER_SEC,
+ sunxi_clockevent.shift);
+ sunxi_clockevent.max_delta_ns = clockevent_delta2ns(0xff,
+ &sunxi_clockevent);
+ sunxi_clockevent.min_delta_ns = clockevent_delta2ns(0x1,
+ &sunxi_clockevent);
+ sunxi_clockevent.cpumask = cpumask_of(0);
+
+ clockevents_register_device(&sunxi_clockevent);
+}
+
+struct sys_timer sunxi_timer = {
+ .init = sunxi_timer_init,
+};