1 files changed, 261 insertions, 0 deletions
diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
new file mode 100644
index 00000000000..32a3d25795d
--- /dev/null
+++ b/drivers/clocksource/mtk_timer.c
@@ -0,0 +1,261 @@
+/*
+ * Mediatek SoCs General-Purpose Timer handling.
+ *
+ * Copyright (C) 2014 Matthias Brugger
+ *
+ * Matthias Brugger <matthias.bgg@gmail.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.
+ */
+
+#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/slab.h>
+
+#define GPT_IRQ_EN_REG		0x00
+#define GPT_IRQ_ENABLE(val)	BIT((val) - 1)
+#define GPT_IRQ_ACK_REG		0x08
+#define GPT_IRQ_ACK(val)	BIT((val) - 1)
+
+#define TIMER_CTRL_REG(val)	(0x10 * (val))
+#define TIMER_CTRL_OP(val)	(((val) & 0x3) << 4)
+#define TIMER_CTRL_OP_ONESHOT	(0)
+#define TIMER_CTRL_OP_REPEAT	(1)
+#define TIMER_CTRL_OP_FREERUN	(3)
+#define TIMER_CTRL_CLEAR	(2)
+#define TIMER_CTRL_ENABLE	(1)
+#define TIMER_CTRL_DISABLE	(0)
+
+#define TIMER_CLK_REG(val)	(0x04 + (0x10 * (val)))
+#define TIMER_CLK_SRC(val)	(((val) & 0x1) << 4)
+#define TIMER_CLK_SRC_SYS13M	(0)
+#define TIMER_CLK_SRC_RTC32K	(1)
+#define TIMER_CLK_DIV1		(0x0)
+#define TIMER_CLK_DIV2		(0x1)
+
+#define TIMER_CNT_REG(val)	(0x08 + (0x10 * (val)))
+#define TIMER_CMP_REG(val)	(0x0C + (0x10 * (val)))
+
+#define GPT_CLK_EVT	1
+#define GPT_CLK_SRC	2
+
+struct mtk_clock_event_device {
+	void __iomem *gpt_base;
+	u32 ticks_per_jiffy;
+	struct clock_event_device dev;
+};
+
+static inline struct mtk_clock_event_device *to_mtk_clk(
+				struct clock_event_device *c)
+{
+	return container_of(c, struct mtk_clock_event_device, dev);
+}
+
+static void mtk_clkevt_time_stop(struct mtk_clock_event_device *evt, u8 timer)
+{
+	u32 val;
+
+	val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
+	writel(val & ~TIMER_CTRL_ENABLE, evt->gpt_base +
+			TIMER_CTRL_REG(timer));
+}
+
+static void mtk_clkevt_time_setup(struct mtk_clock_event_device *evt,
+				unsigned long delay, u8 timer)
+{
+	writel(delay, evt->gpt_base + TIMER_CMP_REG(timer));
+}
+
+static void mtk_clkevt_time_start(struct mtk_clock_event_device *evt,
+		bool periodic, u8 timer)
+{
+	u32 val;
+
+	/* Acknowledge interrupt */
+	writel(GPT_IRQ_ACK(timer), evt->gpt_base + GPT_IRQ_ACK_REG);
+
+	val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
+
+	/* Clear 2 bit timer operation mode field */
+	val &= ~TIMER_CTRL_OP(0x3);
+
+	if (periodic)
+		val |= TIMER_CTRL_OP(TIMER_CTRL_OP_REPEAT);
+	else
+		val |= TIMER_CTRL_OP(TIMER_CTRL_OP_ONESHOT);
+
+	writel(val | TIMER_CTRL_ENABLE | TIMER_CTRL_CLEAR,
+	       evt->gpt_base + TIMER_CTRL_REG(timer));
+}
+
+static void mtk_clkevt_mode(enum clock_event_mode mode,
+				struct clock_event_device *clk)
+{
+	struct mtk_clock_event_device *evt = to_mtk_clk(clk);
+
+	mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		mtk_clkevt_time_setup(evt, evt->ticks_per_jiffy, GPT_CLK_EVT);
+		mtk_clkevt_time_start(evt, true, GPT_CLK_EVT);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		/* Timer is enabled in set_next_event */
+		break;
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	default:
+		/* No more interrupts will occur as source is disabled */
+		break;
+	}
+}
+
+static int mtk_clkevt_next_event(unsigned long event,
+				   struct clock_event_device *clk)
+{
+	struct mtk_clock_event_device *evt = to_mtk_clk(clk);
+
+	mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
+	mtk_clkevt_time_setup(evt, event, GPT_CLK_EVT);
+	mtk_clkevt_time_start(evt, false, GPT_CLK_EVT);
+
+	return 0;
+}
+
+static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
+{
+	struct mtk_clock_event_device *evt = dev_id;
+
+	/* Acknowledge timer0 irq */
+	writel(GPT_IRQ_ACK(GPT_CLK_EVT), evt->gpt_base + GPT_IRQ_ACK_REG);
+	evt->dev.event_handler(&evt->dev);
+
+	return IRQ_HANDLED;
+}
+
+static void mtk_timer_global_reset(struct mtk_clock_event_device *evt)
+{
+	/* Disable all interrupts */
+	writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
+	/* Acknowledge all interrupts */
+	writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
+}
+
+static void
+mtk_timer_setup(struct mtk_clock_event_device *evt, u8 timer, u8 option)
+{
+	writel(TIMER_CTRL_CLEAR | TIMER_CTRL_DISABLE,
+		evt->gpt_base + TIMER_CTRL_REG(timer));
+
+	writel(TIMER_CLK_SRC(TIMER_CLK_SRC_SYS13M) | TIMER_CLK_DIV1,
+			evt->gpt_base + TIMER_CLK_REG(timer));
+
+	writel(0x0, evt->gpt_base + TIMER_CMP_REG(timer));
+
+	writel(TIMER_CTRL_OP(option) | TIMER_CTRL_ENABLE,
+			evt->gpt_base + TIMER_CTRL_REG(timer));
+}
+
+static void mtk_timer_enable_irq(struct mtk_clock_event_device *evt, u8 timer)
+{
+	u32 val;
+
+	val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
+	writel(val | GPT_IRQ_ENABLE(timer),
+			evt->gpt_base + GPT_IRQ_EN_REG);
+}
+
+static void __init mtk_timer_init(struct device_node *node)
+{
+	struct mtk_clock_event_device *evt;
+	struct resource res;
+	unsigned long rate = 0;
+	struct clk *clk;
+
+	evt = kzalloc(sizeof(*evt), GFP_KERNEL);
+	if (!evt) {
+		pr_warn("Can't allocate mtk clock event driver struct");
+		return;
+	}
+
+	evt->dev.name = "mtk_tick";
+	evt->dev.rating = 300;
+	evt->dev.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	evt->dev.set_mode = mtk_clkevt_mode;
+	evt->dev.set_next_event = mtk_clkevt_next_event;
+	evt->dev.cpumask = cpu_possible_mask;
+
+	evt->gpt_base = of_io_request_and_map(node, 0, "mtk-timer");
+	if (IS_ERR(evt->gpt_base)) {
+		pr_warn("Can't get resource\n");
+		return;
+	}
+
+	evt->dev.irq = irq_of_parse_and_map(node, 0);
+	if (evt->dev.irq <= 0) {
+		pr_warn("Can't parse IRQ");
+		goto err_mem;
+	}
+
+	clk = of_clk_get(node, 0);
+	if (IS_ERR(clk)) {
+		pr_warn("Can't get timer clock");
+		goto err_irq;
+	}
+
+	if (clk_prepare_enable(clk)) {
+		pr_warn("Can't prepare clock");
+		goto err_clk_put;
+	}
+	rate = clk_get_rate(clk);
+
+	if (request_irq(evt->dev.irq, mtk_timer_interrupt,
+			IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
+		pr_warn("failed to setup irq %d\n", evt->dev.irq);
+		goto err_clk_disable;
+	}
+
+	evt->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
+
+	mtk_timer_global_reset(evt);
+
+	/* Configure clock source */
+	mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN);
+	clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC),
+			node->name, rate, 300, 32, clocksource_mmio_readl_up);
+
+	/* Configure clock event */
+	mtk_timer_setup(evt, GPT_CLK_EVT, TIMER_CTRL_OP_REPEAT);
+	mtk_timer_enable_irq(evt, GPT_CLK_EVT);
+
+	clockevents_config_and_register(&evt->dev, rate, 0x3,
+					0xffffffff);
+	return;
+
+err_clk_disable:
+	clk_disable_unprepare(clk);
+err_clk_put:
+	clk_put(clk);
+err_irq:
+	irq_dispose_mapping(evt->dev.irq);
+err_mem:
+	iounmap(evt->gpt_base);
+	of_address_to_resource(node, 0, &res);
+	release_mem_region(res.start, resource_size(&res));
+}
+CLOCKSOURCE_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_timer_init);