1 files changed, 285 insertions, 0 deletions
diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c
new file mode 100644
index 000000000000..3b2f94781df4
--- /dev/null
+++ b/drivers/clocksource/tegra20_timer.c
@@ -0,0 +1,285 @@
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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/init.h>
+#include <linux/err.h>
+#include <linux/time.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <asm/mach/time.h>
+#include <asm/smp_twd.h>
+#include <asm/sched_clock.h>
+
+#define RTC_SECONDS            0x08
+#define RTC_SHADOW_SECONDS     0x0c
+#define RTC_MILLISECONDS       0x10
+
+#define TIMERUS_CNTR_1US 0x10
+#define TIMERUS_USEC_CFG 0x14
+#define TIMERUS_CNTR_FREEZE 0x4c
+
+#define TIMER1_BASE 0x0
+#define TIMER2_BASE 0x8
+#define TIMER3_BASE 0x50
+#define TIMER4_BASE 0x58
+
+#define TIMER_PTV 0x0
+#define TIMER_PCR 0x4
+
+static void __iomem *timer_reg_base;
+static void __iomem *rtc_base;
+
+static struct timespec persistent_ts;
+static u64 persistent_ms, last_persistent_ms;
+
+#define timer_writel(value, reg) \
+	__raw_writel(value, timer_reg_base + (reg))
+#define timer_readl(reg) \
+	__raw_readl(timer_reg_base + (reg))
+
+static int tegra_timer_set_next_event(unsigned long cycles,
+					 struct clock_event_device *evt)
+{
+	u32 reg;
+
+	reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
+	timer_writel(reg, TIMER3_BASE + TIMER_PTV);
+
+	return 0;
+}
+
+static void tegra_timer_set_mode(enum clock_event_mode mode,
+				    struct clock_event_device *evt)
+{
+	u32 reg;
+
+	timer_writel(0, TIMER3_BASE + TIMER_PTV);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		reg = 0xC0000000 | ((1000000/HZ)-1);
+		timer_writel(reg, TIMER3_BASE + TIMER_PTV);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		break;
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+	}
+}
+
+static struct clock_event_device tegra_clockevent = {
+	.name		= "timer0",
+	.rating		= 300,
+	.features	= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
+	.set_next_event	= tegra_timer_set_next_event,
+	.set_mode	= tegra_timer_set_mode,
+};
+
+static u32 notrace tegra_read_sched_clock(void)
+{
+	return timer_readl(TIMERUS_CNTR_1US);
+}
+
+/*
+ * tegra_rtc_read - Reads the Tegra RTC registers
+ * Care must be taken that this funciton is not called while the
+ * tegra_rtc driver could be executing to avoid race conditions
+ * on the RTC shadow register
+ */
+static u64 tegra_rtc_read_ms(void)
+{
+	u32 ms = readl(rtc_base + RTC_MILLISECONDS);
+	u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
+	return (u64)s * MSEC_PER_SEC + ms;
+}
+
+/*
+ * tegra_read_persistent_clock -  Return time from a persistent clock.
+ *
+ * Reads the time from a source which isn't disabled during PM, the
+ * 32k sync timer.  Convert the cycles elapsed since last read into
+ * nsecs and adds to a monotonically increasing timespec.
+ * Care must be taken that this funciton is not called while the
+ * tegra_rtc driver could be executing to avoid race conditions
+ * on the RTC shadow register
+ */
+static void tegra_read_persistent_clock(struct timespec *ts)
+{
+	u64 delta;
+	struct timespec *tsp = &persistent_ts;
+
+	last_persistent_ms = persistent_ms;
+	persistent_ms = tegra_rtc_read_ms();
+	delta = persistent_ms - last_persistent_ms;
+
+	timespec_add_ns(tsp, delta * NSEC_PER_MSEC);
+	*ts = *tsp;
+}
+
+static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+	timer_writel(1<<30, TIMER3_BASE + TIMER_PCR);
+	evt->event_handler(evt);
+	return IRQ_HANDLED;
+}
+
+static struct irqaction tegra_timer_irq = {
+	.name		= "timer0",
+	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH,
+	.handler	= tegra_timer_interrupt,
+	.dev_id		= &tegra_clockevent,
+};
+
+static const struct of_device_id timer_match[] __initconst = {
+	{ .compatible = "nvidia,tegra20-timer" },
+	{}
+};
+
+static const struct of_device_id rtc_match[] __initconst = {
+	{ .compatible = "nvidia,tegra20-rtc" },
+	{}
+};
+
+static void __init tegra20_init_timer(void)
+{
+	struct device_node *np;
+	struct clk *clk;
+	unsigned long rate;
+	int ret;
+
+	np = of_find_matching_node(NULL, timer_match);
+	if (!np) {
+		pr_err("Failed to find timer DT node\n");
+		BUG();
+	}
+
+	timer_reg_base = of_iomap(np, 0);
+	if (!timer_reg_base) {
+		pr_err("Can't map timer registers");
+		BUG();
+	}
+
+	tegra_timer_irq.irq = irq_of_parse_and_map(np, 2);
+	if (tegra_timer_irq.irq <= 0) {
+		pr_err("Failed to map timer IRQ\n");
+		BUG();
+	}
+
+	clk = clk_get_sys("timer", NULL);
+	if (IS_ERR(clk)) {
+		pr_warn("Unable to get timer clock. Assuming 12Mhz input clock.\n");
+		rate = 12000000;
+	} else {
+		clk_prepare_enable(clk);
+		rate = clk_get_rate(clk);
+	}
+
+	of_node_put(np);
+
+	np = of_find_matching_node(NULL, rtc_match);
+	if (!np) {
+		pr_err("Failed to find RTC DT node\n");
+		BUG();
+	}
+
+	rtc_base = of_iomap(np, 0);
+	if (!rtc_base) {
+		pr_err("Can't map RTC registers");
+		BUG();
+	}
+
+	/*
+	 * rtc registers are used by read_persistent_clock, keep the rtc clock
+	 * enabled
+	 */
+	clk = clk_get_sys("rtc-tegra", NULL);
+	if (IS_ERR(clk))
+		pr_warn("Unable to get rtc-tegra clock\n");
+	else
+		clk_prepare_enable(clk);
+
+	of_node_put(np);
+
+	switch (rate) {
+	case 12000000:
+		timer_writel(0x000b, TIMERUS_USEC_CFG);
+		break;
+	case 13000000:
+		timer_writel(0x000c, TIMERUS_USEC_CFG);
+		break;
+	case 19200000:
+		timer_writel(0x045f, TIMERUS_USEC_CFG);
+		break;
+	case 26000000:
+		timer_writel(0x0019, TIMERUS_USEC_CFG);
+		break;
+	default:
+		WARN(1, "Unknown clock rate");
+	}
+
+	setup_sched_clock(tegra_read_sched_clock, 32, 1000000);
+
+	if (clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US,
+		"timer_us", 1000000, 300, 32, clocksource_mmio_readl_up)) {
+		pr_err("Failed to register clocksource\n");
+		BUG();
+	}
+
+	ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
+	if (ret) {
+		pr_err("Failed to register timer IRQ: %d\n", ret);
+		BUG();
+	}
+
+	clockevents_calc_mult_shift(&tegra_clockevent, 1000000, 5);
+	tegra_clockevent.max_delta_ns =
+		clockevent_delta2ns(0x1fffffff, &tegra_clockevent);
+	tegra_clockevent.min_delta_ns =
+		clockevent_delta2ns(0x1, &tegra_clockevent);
+	tegra_clockevent.cpumask = cpu_all_mask;
+	tegra_clockevent.irq = tegra_timer_irq.irq;
+	clockevents_register_device(&tegra_clockevent);
+#ifdef CONFIG_HAVE_ARM_TWD
+	twd_local_timer_of_register();
+#endif
+	register_persistent_clock(NULL, tegra_read_persistent_clock);
+}
+CLOCKSOURCE_OF_DECLARE(tegra20, "nvidia,tegra20-timer", tegra20_init_timer);
+
+#ifdef CONFIG_PM
+static u32 usec_config;
+
+void tegra_timer_suspend(void)
+{
+	usec_config = timer_readl(TIMERUS_USEC_CFG);
+}
+
+void tegra_timer_resume(void)
+{
+	timer_writel(usec_config, TIMERUS_USEC_CFG);
+}
+#endif