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>

3 files changed, 174 insertions, 0 deletions

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 6a78073c3808..a0985732f1e2 100644
--- a/drivers/clocksource/Kconfig
+++ b/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
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 603be366f762..36f06de4c5ab 100644
--- a/drivers/clocksource/Makefile
+++ b/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
diff --git a/drivers/clocksource/sunxi_timer.c b/drivers/clocksource/sunxi_timer.c
new file mode 100644
index 000000000000..3c46434b64cb
--- /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,
+};