ARM: plat-nomadik: move MTU, kill plat-nomadik

This moves the MTU timer driver from arch/arm/plat-nomadik
to drivers/clocksource and moves the header file to the
platform_data directory.

As this moves the last file being compiled to an object out
of arch/arm/plat-nomadik, we have to "turn off the light"
and delete the plat-nomadik directory, because it is not
allowed to have an empty Makefile in a plat-* directory.
This is probably also a desired side effect of depopulating
the arch/arm directory of drivers. Luckily we have just
deleted all the <plat/*> include files prior to this so
by moving the last one we may delete the directory.

After this all the Ux500 and Nomadik device drivers live
outside of the arch/arm hierarchy.

Cc: Alessandro Rubini <rubini@unipv.it>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 241 insertions, 1 deletions

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 6a78073c3808..c9f67de8b7b4 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -22,6 +22,21 @@ config DW_APB_TIMER_OF
 config ARMADA_370_XP_TIMER
 	bool
 
+config CLKSRC_NOMADIK_MTU
+	bool
+	depends on (ARCH_NOMADIK || ARCH_U8500)
+	select CLKSRC_MMIO
+	help
+	  Support for Multi Timer Unit. MTU provides access
+	  to multiple interrupt generating programmable
+	  32-bit free running decrementing counters.
+
+config CLKSRC_NOMADIK_MTU_SCHED_CLOCK
+	bool
+	depends on CLKSRC_NOMADIK_MTU
+	help
+	  Use the Multi Timer Unit as the sched_clock.
+
 config CLKSRC_DBX500_PRCMU
 	bool "Clocksource PRCMU Timer"
 	depends on UX500_SOC_DB8500
@@ -31,7 +46,7 @@ config CLKSRC_DBX500_PRCMU
 
 config CLKSRC_DBX500_PRCMU_SCHED_CLOCK
 	bool "Clocksource PRCMU Timer sched_clock"
-	depends on (CLKSRC_DBX500_PRCMU && !NOMADIK_MTU_SCHED_CLOCK)
+	depends on (CLKSRC_DBX500_PRCMU && !CLKSRC_NOMADIK_MTU_SCHED_CLOCK)
 	default y
 	help
 	  Use the always on PRCMU Timer as sched_clock
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 603be366f762..24fb888ee0a2 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_CLKBLD_I8253)	+= i8253.o
 obj-$(CONFIG_CLKSRC_MMIO)	+= mmio.o
 obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
 obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
+obj-$(CONFIG_CLKSRC_NOMADIK_MTU)	+= nomadik-mtu.o
 obj-$(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
diff --git a/drivers/clocksource/nomadik-mtu.c b/drivers/clocksource/nomadik-mtu.c
new file mode 100644
index 000000000000..23c780ba0d35
--- /dev/null
+++ b/drivers/clocksource/nomadik-mtu.c
@@ -0,0 +1,224 @@
+/*
+ * 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/clk.h>
+#include <linux/jiffies.h>
+#include <linux/err.h>
+#include <linux/platform_data/clocksource-nomadik-mtu.h>
+#include <asm/mach/time.h>
+#include <asm/sched_clock.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 */
+
+#ifdef CONFIG_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 u32 notrace nomadik_read_sched_clock(void)
+{
+	if (unlikely(!mtu_base))
+		return 0;
+
+	return -readl(mtu_base + MTU_VAL(0));
+}
+#endif
+
+/* 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;
+}
+
+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 struct clock_event_device nmdk_clkevt = {
+	.name		= "mtu_1",
+	.features	= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
+	.rating		= 200,
+	.set_mode	= nmdk_clkevt_mode,
+	.set_next_event	= nmdk_clkevt_next,
+};
+
+/*
+ * 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_DISABLED | IRQF_TIMER,
+	.handler	= nmdk_timer_interrupt,
+	.dev_id		= &nmdk_clkevt,
+};
+
+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));
+}
+
+void __init nmdk_timer_init(void __iomem *base, int irq)
+{
+	unsigned long rate;
+	struct clk *clk0;
+
+	mtu_base = base;
+	clk0 = clk_get_sys("mtu0", NULL);
+	BUG_ON(IS_ERR(clk0));
+	BUG_ON(clk_prepare(clk0) < 0);
+	BUG_ON(clk_enable(clk0) < 0);
+
+	/*
+	 * 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(clk0);
+	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_NOMADIK_MTU_SCHED_CLOCK
+	setup_sched_clock(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);
+	clockevents_config_and_register(&nmdk_clkevt, rate, 2, 0xffffffffU);
+}