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>

Documentation/devicetree/bindings/timer/allwinner,sunxi-timer.txt

+Allwinner A1X SoCs Timer Controller
+
+Required properties:
+
+- compatible : should be "allwinner,sunxi-timer"
+- reg : Specifies base physical address and size of the registers.
+- interrupts : The interrupt of the first timer
+- clocks: phandle to the source clock (usually a 24 MHz fixed clock)
+
+Example:
+
+timer {
+	compatible = "allwinner,sunxi-timer";
+	reg = <0x01c20c00 0x400>;
+	interrupts = <22>;
+	clocks = <&osc>;
+};

drivers/clocksource/Kconfig

@@ -22,6 +22,9 @@ config DW_APB_TIMER_OF
 config ARMADA_370_XP_TIMER
 	bool
 
+config SUNXI_TIMER
+	bool
+
 config CLKSRC_DBX500_PRCMU
 	bool "Clocksource PRCMU Timer"
 	depends on UX500_SOC_DB8500

drivers/clocksource/Makefile

@@ -14,5 +14,6 @@ obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
 obj-$(CONFIG_CLKSRC_DBX500_PRCMU)	+= clksrc-dbx500-prcmu.o
 obj-$(CONFIG_ARMADA_370_XP_TIMER)	+= time-armada-370-xp.o
 obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835_timer.o
+obj-$(CONFIG_SUNXI_TIMER)	+= sunxi_timer.o
 
 obj-$(CONFIG_CLKSRC_ARM_GENERIC)	+= arm_generic.o

drivers/clocksource/sunxi_timer.c

+/*
+ * 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,
+};

include/linux/sunxi_timer.h

+/*
+ * Copyright 2012 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * 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.
+ */
+
+#ifndef __SUNXI_TIMER_H
+#define __SUNXI_TIMER_H
+
+#include <asm/mach/time.h>
+
+extern struct sys_timer sunxi_timer;
+
+#endif