ARM: 5786/1: Introduce plat-nomadik, MTU code re-organization

Introduce the plat-nomadik folder for ST-Ericsson
machines including the existing nomadik 8815 architecture.
This also moves the existing MTU (MultiTimerUnit)
of nomadik 8815 to the proposed plat-nomadik and adds
HAS_MTU. The patch has been re-based to 2.6.32-rc6

Signed-off-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com>
Acked-by: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

4 files changed, 222 insertions, 0 deletions

diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig
new file mode 100644
index 00000000000..e27ee313405
--- /dev/null
+++ b/arch/arm/plat-nomadik/Kconfig
@@ -0,0 +1,22 @@
+# We keep common IP's here for Nomadik and other similar
+# familiy of processors from ST-Ericsson. At the moment we have
+# just MTU, others to follow soon.
+
+config PLAT_NOMADIK
+	bool
+	depends on ARCH_NOMADIK
+	default y
+	help
+	  Common platform code for Nomadik and other ST-Ericsson
+	  platforms.
+
+if PLAT_NOMADIK
+
+config HAS_MTU
+	bool
+	help
+	  Support for Multi Timer Unit. MTU provides access
+	  to multiple interrupt generating programmable
+	  32-bit free running decrementing counters.
+
+endif
diff --git a/arch/arm/plat-nomadik/Makefile b/arch/arm/plat-nomadik/Makefile
new file mode 100644
index 00000000000..37c7cdd0f8f
--- /dev/null
+++ b/arch/arm/plat-nomadik/Makefile
@@ -0,0 +1,5 @@
+# arch/arm/plat-nomadik/Makefile
+# Copyright 2009 ST-Ericsson
+# Licensed under GPLv2
+
+obj-$(CONFIG_HAS_MTU)	+= timer.o
diff --git a/arch/arm/plat-nomadik/include/plat/mtu.h b/arch/arm/plat-nomadik/include/plat/mtu.h
new file mode 100644
index 00000000000..42c907258b1
--- /dev/null
+++ b/arch/arm/plat-nomadik/include/plat/mtu.h
@@ -0,0 +1,48 @@
+#ifndef __PLAT_MTU_H
+#define __PLAT_MTU_H
+
+/* should be set by the platform code */
+extern void __iomem *mtu_base;
+
+/*
+ * 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
+
+#endif /* __PLAT_MTU_H */
+
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
new file mode 100644
index 00000000000..62f18ad43a2
--- /dev/null
+++ b/arch/arm/plat-nomadik/timer.c
@@ -0,0 +1,147 @@
+/*
+ *  linux/arch/arm/mach-nomadik/timer.c
+ *
+ * Copyright (C) 2008 STMicroelectronics
+ * Copyright (C) 2009 Alessandro Rubini, somewhat based on at91sam926x
+ *
+ * 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/jiffies.h>
+#include <asm/mach/time.h>
+
+#include <plat/mtu.h>
+
+static u32	nmdk_count;		/* accumulated count */
+static u32	nmdk_cycle;		/* write-once */
+
+/* setup by the platform code */
+void __iomem *mtu_base;
+
+/*
+ * clocksource: the MTU device is a decrementing counters, so we negate
+ * the value being read.
+ */
+static cycle_t nmdk_read_timer(struct clocksource *cs)
+{
+	u32 count = readl(mtu_base + MTU_VAL(0));
+	return nmdk_count + nmdk_cycle - count;
+
+}
+
+static struct clocksource nmdk_clksrc = {
+	.name		= "mtu_0",
+	.rating		= 120,
+	.read		= nmdk_read_timer,
+	.shift		= 20,
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+/*
+ * Clockevent device: currently only periodic mode is supported
+ */
+static void nmdk_clkevt_mode(enum clock_event_mode mode,
+			     struct clock_event_device *dev)
+{
+	unsigned long flags;
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		/* enable interrupts -- and count current value? */
+		raw_local_irq_save(flags);
+		writel(readl(mtu_base + MTU_IMSC) | 1, mtu_base + MTU_IMSC);
+		raw_local_irq_restore(flags);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		BUG(); /* Not supported, yet */
+		/* FALLTHROUGH */
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_UNUSED:
+		/* disable irq */
+		raw_local_irq_save(flags);
+		writel(readl(mtu_base + MTU_IMSC) & ~1, mtu_base + MTU_IMSC);
+		raw_local_irq_restore(flags);
+		break;
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+	}
+}
+
+static struct clock_event_device nmdk_clkevt = {
+	.name		= "mtu_0",
+	.features	= CLOCK_EVT_FEAT_PERIODIC,
+	.shift		= 32,
+	.rating		= 100,
+	.set_mode	= nmdk_clkevt_mode,
+};
+
+/*
+ * IRQ Handler for the timer 0 of the MTU block. The irq is not shared
+ * as we are the only users of mtu0 by now.
+ */
+static irqreturn_t nmdk_timer_interrupt(int irq, void *dev_id)
+{
+	/* ack: "interrupt clear register" */
+	writel(1 << 0, mtu_base + MTU_ICR);
+
+	/* we can't count lost ticks, unfortunately */
+	nmdk_count += nmdk_cycle;
+	nmdk_clkevt.event_handler(&nmdk_clkevt);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Set up timer interrupt, and return the current time in seconds.
+ */
+static struct irqaction nmdk_timer_irq = {
+	.name		= "Nomadik Timer Tick",
+	.flags		= IRQF_DISABLED | IRQF_TIMER,
+	.handler	= nmdk_timer_interrupt,
+};
+
+static void nmdk_timer_reset(void)
+{
+	u32 cr;
+
+	writel(0, mtu_base + MTU_CR(0)); /* off */
+
+	/* 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));
+	cr = MTU_CRn_PERIODIC | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS;
+	writel(cr, mtu_base + MTU_CR(0));
+	writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0));
+}
+
+void __init nmdk_timer_init(void)
+{
+	unsigned long rate;
+	int bits;
+
+	rate = CLOCK_TICK_RATE; /* 2.4MHz */
+	nmdk_cycle = (rate + HZ/2) / HZ;
+
+	/* Init the timer and register clocksource */
+	nmdk_timer_reset();
+
+	nmdk_clksrc.mult = clocksource_hz2mult(rate, nmdk_clksrc.shift);
+	bits =  8*sizeof(nmdk_count);
+	nmdk_clksrc.mask = CLOCKSOURCE_MASK(bits);
+
+	if (clocksource_register(&nmdk_clksrc))
+		printk(KERN_ERR "timer: failed to initialize clock "
+			"source %s\n", nmdk_clksrc.name);
+
+	/* Register irq and clockevents */
+	setup_irq(IRQ_MTU0, &nmdk_timer_irq);
+	nmdk_clkevt.mult = div_sc(rate, NSEC_PER_SEC, nmdk_clkevt.shift);
+	nmdk_clkevt.cpumask = cpumask_of(0);
+	clockevents_register_device(&nmdk_clkevt);
+}