3 files changed, 267 insertions, 0 deletions

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index b17c9098ba36..497356d4dc70 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -151,6 +151,11 @@ config VF_PIT_TIMER
 config SYS_SUPPORTS_SH_CMT
         bool
 
+config MTK_TIMER
+        select CLKSRC_OF
+        select CLKSRC_MMIO
+        bool
+
 config SYS_SUPPORTS_SH_MTU2
         bool
 
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 800b1303c236..da1ac09dc771 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_CLKSRC_SAMSUNG_PWM)	+= samsung_pwm_timer.o
 obj-$(CONFIG_FSL_FTM_TIMER)     += fsl_ftm_timer.o
 obj-$(CONFIG_VF_PIT_TIMER)      += vf_pit_timer.o
 obj-$(CONFIG_CLKSRC_QCOM)       += qcom-timer.o
+obj-$(CONFIG_MTK_TIMER)         += mtk_timer.o
 
 obj-$(CONFIG_ARM_ARCH_TIMER)            += arm_arch_timer.o
 obj-$(CONFIG_ARM_GLOBAL_TIMER)          += arm_global_timer.o
diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
new file mode 100644
index 000000000000..32a3d25795d3
--- /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);