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>

1 files changed, 147 insertions, 0 deletions

diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
new file mode 100644
index 000000000000..62f18ad43a28
--- /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);
+}