1 files changed, 273 insertions, 0 deletions
diff --git a/drivers/clocksource/nomadik-mtu.c b/drivers/clocksource/nomadik-mtu.c
new file mode 100644
index 000000000..a709cfa49
--- /dev/null
+++ b/drivers/clocksource/nomadik-mtu.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright (C) 2008 STMicroelectronics
+ * Copyright (C) 2010 Alessandro Rubini
+ * Copyright (C) 2010 Linus Walleij for ST-Ericsson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/clk.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/sched_clock.h>
+#include <asm/mach/time.h>
+
+/*
+ * The MTU device hosts four different counters, with 4 set of
+ * registers. These are register names.
+ */
+
+#define MTU_IMSC	0x00	/* Interrupt mask set/clear */
+#define MTU_RIS		0x04	/* Raw interrupt status */
+#define MTU_MIS		0x08	/* Masked interrupt status */
+#define MTU_ICR		0x0C	/* Interrupt clear register */
+
+/* per-timer registers take 0..3 as argument */
+#define MTU_LR(x)	(0x10 + 0x10 * (x) + 0x00)	/* Load value */
+#define MTU_VAL(x)	(0x10 + 0x10 * (x) + 0x04)	/* Current value */
+#define MTU_CR(x)	(0x10 + 0x10 * (x) + 0x08)	/* Control reg */
+#define MTU_BGLR(x)	(0x10 + 0x10 * (x) + 0x0c)	/* At next overflow */
+
+/* bits for the control register */
+#define MTU_CRn_ENA		0x80
+#define MTU_CRn_PERIODIC	0x40	/* if 0 = free-running */
+#define MTU_CRn_PRESCALE_MASK	0x0c
+#define MTU_CRn_PRESCALE_1		0x00
+#define MTU_CRn_PRESCALE_16		0x04
+#define MTU_CRn_PRESCALE_256		0x08
+#define MTU_CRn_32BITS		0x02
+#define MTU_CRn_ONESHOT		0x01	/* if 0 = wraps reloading from BGLR*/
+
+/* Other registers are usual amba/primecell registers, currently not used */
+#define MTU_ITCR	0xff0
+#define MTU_ITOP	0xff4
+
+#define MTU_PERIPH_ID0	0xfe0
+#define MTU_PERIPH_ID1	0xfe4
+#define MTU_PERIPH_ID2	0xfe8
+#define MTU_PERIPH_ID3	0xfeC
+
+#define MTU_PCELL0	0xff0
+#define MTU_PCELL1	0xff4
+#define MTU_PCELL2	0xff8
+#define MTU_PCELL3	0xffC
+
+static void __iomem *mtu_base;
+static bool clkevt_periodic;
+static u32 clk_prescale;
+static u32 nmdk_cycle;		/* write-once */
+static struct delay_timer mtu_delay_timer;
+
+#ifdef CONFIG_CLKSRC_NOMADIK_MTU_SCHED_CLOCK
+/*
+ * Override the global weak sched_clock symbol with this
+ * local implementation which uses the clocksource to get some
+ * better resolution when scheduling the kernel.
+ */
+static u64 notrace nomadik_read_sched_clock(void)
+{
+	if (unlikely(!mtu_base))
+		return 0;
+
+	return -readl(mtu_base + MTU_VAL(0));
+}
+#endif
+
+static unsigned long nmdk_timer_read_current_timer(void)
+{
+	return ~readl_relaxed(mtu_base + MTU_VAL(0));
+}
+
+/* Clockevent device: use one-shot mode */
+static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev)
+{
+	writel(1 << 1, mtu_base + MTU_IMSC);
+	writel(evt, mtu_base + MTU_LR(1));
+	/* Load highest value, enable device, enable interrupts */
+	writel(MTU_CRn_ONESHOT | clk_prescale |
+	       MTU_CRn_32BITS | MTU_CRn_ENA,
+	       mtu_base + MTU_CR(1));
+
+	return 0;
+}
+
+static void nmdk_clkevt_reset(void)
+{
+	if (clkevt_periodic) {
+		/* Timer: configure load and background-load, and fire it up */
+		writel(nmdk_cycle, mtu_base + MTU_LR(1));
+		writel(nmdk_cycle, mtu_base + MTU_BGLR(1));
+
+		writel(MTU_CRn_PERIODIC | clk_prescale |
+		       MTU_CRn_32BITS | MTU_CRn_ENA,
+		       mtu_base + MTU_CR(1));
+		writel(1 << 1, mtu_base + MTU_IMSC);
+	} else {
+		/* Generate an interrupt to start the clockevent again */
+		(void) nmdk_clkevt_next(nmdk_cycle, NULL);
+	}
+}
+
+static void nmdk_clkevt_mode(enum clock_event_mode mode,
+			     struct clock_event_device *dev)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		clkevt_periodic = true;
+		nmdk_clkevt_reset();
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		clkevt_periodic = false;
+		break;
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_UNUSED:
+		writel(0, mtu_base + MTU_IMSC);
+		/* disable timer */
+		writel(0, mtu_base + MTU_CR(1));
+		/* load some high default value */
+		writel(0xffffffff, mtu_base + MTU_LR(1));
+		break;
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+	}
+}
+
+static void nmdk_clksrc_reset(void)
+{
+	/* Disable */
+	writel(0, mtu_base + MTU_CR(0));
+
+	/* ClockSource: configure load and background-load, and fire it up */
+	writel(nmdk_cycle, mtu_base + MTU_LR(0));
+	writel(nmdk_cycle, mtu_base + MTU_BGLR(0));
+
+	writel(clk_prescale | MTU_CRn_32BITS | MTU_CRn_ENA,
+	       mtu_base + MTU_CR(0));
+}
+
+static void nmdk_clkevt_resume(struct clock_event_device *cedev)
+{
+	nmdk_clkevt_reset();
+	nmdk_clksrc_reset();
+}
+
+static struct clock_event_device nmdk_clkevt = {
+	.name		= "mtu_1",
+	.features	= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC |
+	                  CLOCK_EVT_FEAT_DYNIRQ,
+	.rating		= 200,
+	.set_mode	= nmdk_clkevt_mode,
+	.set_next_event	= nmdk_clkevt_next,
+	.resume		= nmdk_clkevt_resume,
+};
+
+/*
+ * IRQ Handler for timer 1 of the MTU block.
+ */
+static irqreturn_t nmdk_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evdev = dev_id;
+
+	writel(1 << 1, mtu_base + MTU_ICR); /* Interrupt clear reg */
+	evdev->event_handler(evdev);
+	return IRQ_HANDLED;
+}
+
+static struct irqaction nmdk_timer_irq = {
+	.name		= "Nomadik Timer Tick",
+	.flags		= IRQF_TIMER,
+	.handler	= nmdk_timer_interrupt,
+	.dev_id		= &nmdk_clkevt,
+};
+
+static void __init nmdk_timer_init(void __iomem *base, int irq,
+				   struct clk *pclk, struct clk *clk)
+{
+	unsigned long rate;
+
+	mtu_base = base;
+
+	BUG_ON(clk_prepare_enable(pclk));
+	BUG_ON(clk_prepare_enable(clk));
+
+	/*
+	 * Tick rate is 2.4MHz for Nomadik and 2.4Mhz, 100MHz or 133 MHz
+	 * for ux500.
+	 * Use a divide-by-16 counter if the tick rate is more than 32MHz.
+	 * At 32 MHz, the timer (with 32 bit counter) can be programmed
+	 * to wake-up at a max 127s a head in time. Dividing a 2.4 MHz timer
+	 * with 16 gives too low timer resolution.
+	 */
+	rate = clk_get_rate(clk);
+	if (rate > 32000000) {
+		rate /= 16;
+		clk_prescale = MTU_CRn_PRESCALE_16;
+	} else {
+		clk_prescale = MTU_CRn_PRESCALE_1;
+	}
+
+	/* Cycles for periodic mode */
+	nmdk_cycle = DIV_ROUND_CLOSEST(rate, HZ);
+
+
+	/* Timer 0 is the free running clocksource */
+	nmdk_clksrc_reset();
+
+	if (clocksource_mmio_init(mtu_base + MTU_VAL(0), "mtu_0",
+			rate, 200, 32, clocksource_mmio_readl_down))
+		pr_err("timer: failed to initialize clock source %s\n",
+		       "mtu_0");
+
+#ifdef CONFIG_CLKSRC_NOMADIK_MTU_SCHED_CLOCK
+	sched_clock_register(nomadik_read_sched_clock, 32, rate);
+#endif
+
+	/* Timer 1 is used for events, register irq and clockevents */
+	setup_irq(irq, &nmdk_timer_irq);
+	nmdk_clkevt.cpumask = cpumask_of(0);
+	nmdk_clkevt.irq = irq;
+	clockevents_config_and_register(&nmdk_clkevt, rate, 2, 0xffffffffU);
+
+	mtu_delay_timer.read_current_timer = &nmdk_timer_read_current_timer;
+	mtu_delay_timer.freq = rate;
+	register_current_timer_delay(&mtu_delay_timer);
+}
+
+static void __init nmdk_timer_of_init(struct device_node *node)
+{
+	struct clk *pclk;
+	struct clk *clk;
+	void __iomem *base;
+	int irq;
+
+	base = of_iomap(node, 0);
+	if (!base)
+		panic("Can't remap registers");
+
+	pclk = of_clk_get_by_name(node, "apb_pclk");
+	if (IS_ERR(pclk))
+		panic("could not get apb_pclk");
+
+	clk = of_clk_get_by_name(node, "timclk");
+	if (IS_ERR(clk))
+		panic("could not get timclk");
+
+	irq = irq_of_parse_and_map(node, 0);
+	if (irq <= 0)
+		panic("Can't parse IRQ");
+
+	nmdk_timer_init(base, irq, pclk, clk);
+}
+CLOCKSOURCE_OF_DECLARE(nomadik_mtu, "st,nomadik-mtu",
+		       nmdk_timer_of_init);