sh: generic clockevent broadcast support.

This hooks up GENERIC_CLOCKEVENTS_BROADCAST and a dummy local timer,
which we call in to from the timer IPI when no other local timer is
provided.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/Kconfig

@@ -66,6 +66,9 @@ config GENERIC_TIME
 config GENERIC_CLOCKEVENTS
 	def_bool n
 
+config GENERIC_CLOCKEVENTS_BROADCAST
+	bool
+
 config GENERIC_LOCKBREAK
 	def_bool y
 	depends on SMP && PREEMPT
@@ -323,6 +326,7 @@ config CPU_SUBTYPE_SHX3
 	select ARCH_SPARSEMEM_ENABLE
 	select SYS_SUPPORTS_NUMA
 	select SYS_SUPPORTS_SMP
+	select GENERIC_CLOCKEVENTS_BROADCAST
 
 # SH4AL-DSP Processor Support
 

arch/sh/include/asm/smp.h

@@ -33,6 +33,9 @@ enum {
 void smp_message_recv(unsigned int msg);
 void smp_timer_broadcast(cpumask_t mask);
 
+void local_timer_interrupt(void);
+void local_timer_setup(unsigned int cpu);
+
 void plat_smp_setup(void);
 void plat_prepare_cpus(unsigned int max_cpus);
 int plat_smp_processor_id(void);

arch/sh/kernel/smp.c

@@ -84,9 +84,12 @@ asmlinkage void __cpuinit start_secondary(void)
 
 	local_irq_enable();
 
+	cpu = smp_processor_id();
+
+	/* Enable local timers */
+	local_timer_setup(cpu);
 	calibrate_delay();
 
-	cpu = smp_processor_id();
 	smp_store_cpu_info(cpu);
 
 	cpu_set(cpu, cpu_online_map);
@@ -195,7 +198,7 @@ void smp_timer_broadcast(cpumask_t mask)
 static void ipi_timer(void)
 {
 	irq_enter();
-	/* XXX ... */
+	local_timer_interrupt();
 	irq_exit();
 }
 

arch/sh/kernel/time_32.c

 /*
- *  arch/sh/kernel/time.c
+ *  arch/sh/kernel/time_32.c
  *
  *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
  *  Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
- *  Copyright (C) 2002 - 2007  Paul Mundt
+ *  Copyright (C) 2002 - 2008  Paul Mundt
  *  Copyright (C) 2002  M. R. Brown  <mrbrown@linux-sh.org>
  *
  *  Some code taken from i386 version.
@@ -16,6 +16,7 @@
 #include <linux/timex.h>
 #include <linux/sched.h>
 #include <linux/clockchips.h>
+#include <linux/smp.h>
 #include <asm/clock.h>
 #include <asm/rtc.h>
 #include <asm/timer.h>
@@ -260,6 +261,10 @@ void __init time_init(void)
 	sys_timer = get_sys_timer();
 	printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+	local_timer_setup(smp_processor_id());
+#endif
+
 	if (sys_timer->ops->read)
 		clocksource_sh.read = sys_timer->ops->read;
 

arch/sh/kernel/timers/Makefile

@@ -8,3 +8,4 @@ obj-$(CONFIG_SH_TMU)		+= timer-tmu.o
 obj-$(CONFIG_SH_MTU2)		+= timer-mtu2.o
 obj-$(CONFIG_SH_CMT)		+= timer-cmt.o
 
+obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)	+= timer-broadcast.o

arch/sh/kernel/timers/timer-broadcast.c

+/*
+ * Dummy local timer
+ *
+ * Copyright (C) 2008  Paul Mundt
+ *
+ * cloned from:
+ *
+ *  linux/arch/arm/mach-realview/localtimer.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/percpu.h>
+#include <linux/clockchips.h>
+#include <linux/irq.h>
+
+static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);
+
+/*
+ * Used on SMP for either the local timer or SMP_MSG_TIMER
+ */
+void local_timer_interrupt(void)
+{
+	struct clock_event_device *clk = &__get_cpu_var(local_clockevent);
+
+	clk->event_handler(clk);
+}
+
+static void dummy_timer_set_mode(enum clock_event_mode mode,
+				 struct clock_event_device *clk)
+{
+}
+
+void __cpuinit local_timer_setup(unsigned int cpu)
+{
+	struct clock_event_device *clk = &per_cpu(local_clockevent, cpu);
+
+	clk->name		= "dummy_timer";
+	clk->features		= CLOCK_EVT_FEAT_DUMMY;
+	clk->rating		= 200;
+	clk->mult		= 1;
+	clk->set_mode		= dummy_timer_set_mode;
+	clk->broadcast		= smp_timer_broadcast;
+	clk->cpumask		= cpumask_of_cpu(cpu);
+
+	clockevents_register_device(clk);
+}