[ARM] smp: allow re-use of realview localtimer TWD support
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 90ffbaf..ff89d0b 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -23,6 +23,7 @@
obj-$(CONFIG_PCI) += bios32.o isa.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o
+obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_KPROBES) += kprobes.o kprobes-decode.o
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
new file mode 100644
index 0000000..aabd62d
--- /dev/null
+++ b/arch/arm/kernel/smp_twd.c
@@ -0,0 +1,173 @@
+/*
+ * linux/arch/arm/kernel/smp_twd.c
+ *
+ * Copyright (C) 2002 ARM Ltd.
+ * All Rights Reserved
+ *
+ * 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/kernel.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/smp.h>
+#include <linux/jiffies.h>
+#include <linux/clockchips.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+
+#include <asm/smp_twd.h>
+#include <asm/hardware/gic.h>
+
+#define TWD_TIMER_LOAD 0x00
+#define TWD_TIMER_COUNTER 0x04
+#define TWD_TIMER_CONTROL 0x08
+#define TWD_TIMER_INTSTAT 0x0C
+
+#define TWD_WDOG_LOAD 0x20
+#define TWD_WDOG_COUNTER 0x24
+#define TWD_WDOG_CONTROL 0x28
+#define TWD_WDOG_INTSTAT 0x2C
+#define TWD_WDOG_RESETSTAT 0x30
+#define TWD_WDOG_DISABLE 0x34
+
+#define TWD_TIMER_CONTROL_ENABLE (1 << 0)
+#define TWD_TIMER_CONTROL_ONESHOT (0 << 1)
+#define TWD_TIMER_CONTROL_PERIODIC (1 << 1)
+#define TWD_TIMER_CONTROL_IT_ENABLE (1 << 2)
+
+/* set up by the platform code */
+void __iomem *twd_base;
+
+static unsigned long twd_timer_rate;
+
+static void twd_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *clk)
+{
+ unsigned long ctrl;
+
+ switch(mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ /* timer load already set up */
+ ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
+ | TWD_TIMER_CONTROL_PERIODIC;
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ /* period set, and timer enabled in 'next_event' hook */
+ ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT;
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ default:
+ ctrl = 0;
+ }
+
+ __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
+}
+
+static int twd_set_next_event(unsigned long evt,
+ struct clock_event_device *unused)
+{
+ unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);
+
+ __raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
+ __raw_writel(ctrl | TWD_TIMER_CONTROL_ENABLE, twd_base + TWD_TIMER_CONTROL);
+
+ return 0;
+}
+
+/*
+ * local_timer_ack: checks for a local timer interrupt.
+ *
+ * If a local timer interrupt has occurred, acknowledge and return 1.
+ * Otherwise, return 0.
+ */
+int twd_timer_ack(void)
+{
+ if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
+ __raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
+ return 1;
+ }
+
+ return 0;
+}
+
+static void __cpuinit twd_calibrate_rate(void)
+{
+ unsigned long load, count;
+ u64 waitjiffies;
+
+ /*
+ * If this is the first time round, we need to work out how fast
+ * the timer ticks
+ */
+ if (twd_timer_rate == 0) {
+ printk("Calibrating local timer... ");
+
+ /* Wait for a tick to start */
+ waitjiffies = get_jiffies_64() + 1;
+
+ while (get_jiffies_64() < waitjiffies)
+ udelay(10);
+
+ /* OK, now the tick has started, let's get the timer going */
+ waitjiffies += 5;
+
+ /* enable, no interrupt or reload */
+ __raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);
+
+ /* maximum value */
+ __raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
+
+ while (get_jiffies_64() < waitjiffies)
+ udelay(10);
+
+ count = __raw_readl(twd_base + TWD_TIMER_COUNTER);
+
+ twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
+
+ printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
+ (twd_timer_rate / 100000) % 100);
+ }
+
+ load = twd_timer_rate / HZ;
+
+ __raw_writel(load, twd_base + TWD_TIMER_LOAD);
+}
+
+/*
+ * Setup the local clock events for a CPU.
+ */
+void __cpuinit twd_timer_setup(struct clock_event_device *clk)
+{
+ unsigned long flags;
+
+ twd_calibrate_rate();
+
+ clk->name = "local_timer";
+ clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ clk->rating = 350;
+ clk->set_mode = twd_set_mode;
+ clk->set_next_event = twd_set_next_event;
+ clk->shift = 20;
+ clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift);
+ clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk);
+ clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
+
+ /* Make sure our local interrupt controller has this enabled */
+ local_irq_save(flags);
+ get_irq_chip(clk->irq)->unmask(clk->irq);
+ local_irq_restore(flags);
+
+ clockevents_register_device(clk);
+}
+
+/*
+ * take a local timer down
+ */
+void __cpuexit twd_timer_stop(void)
+{
+ __raw_writel(0, twd_base + TWD_TIMER_CONTROL);
+}