ENGR00175308-1 MX6Q PM: cpu hotplug on earlysuspend

Add cpu hotplug support when system entry in earlysyspend.
With this patch, when system entery in earlysuspend, it will
record the online cpus, then hotplut none-bootable cpus,
and in late resume, it will boot up the recorded hotplug cpus.

Signed-off-by: Lin Fuzhen <fuzhen.lin@freescale.com>

3 files changed, 119 insertions, 0 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index f8a559ce65d3..f6f6973664b8 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -56,6 +56,13 @@ config CPUFREQ_GOV_ON_EARLYSUPSEND
 	help
 	 Also will restore to original cpu frequency governor when device is resumed
 
+config CPUHOTPLUG_EARLYSUSPEND
+	bool "hotplug cpu when device enters early suspend"
+	depends on HAS_EARLYSUSPEND && SMP
+	default n
+	help
+	 Will restore to original cpu nums online when device is resumed
+
 config WAKELOCK
 	bool "Wake lock"
 	depends on PM && RTC_CLASS
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index d1fb60636fd3..e4fa86da5859 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_EARLYSUSPEND)	+= earlysuspend.o
 obj-$(CONFIG_CONSOLE_EARLYSUSPEND)	+= consoleearlysuspend.o
 obj-$(CONFIG_FB_EARLYSUSPEND)	+= fbearlysuspend.o
 obj-$(CONFIG_CPUFREQ_GOV_ON_EARLYSUPSEND) 	+= cpufreq_earlysuspend.o
+obj-$(CONFIG_CPUHOTPLUG_EARLYSUSPEND) 	+= cpuhotplug_earlysuspend.o
 obj-$(CONFIG_SUSPEND_TIME)	+= suspend_time.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
diff --git a/kernel/power/cpuhotplug_earlysuspend.c b/kernel/power/cpuhotplug_earlysuspend.c
new file mode 100644
index 000000000000..4b12c7e96dec
--- /dev/null
+++ b/kernel/power/cpuhotplug_earlysuspend.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2011-2012 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#include <linux/earlysuspend.h>
+#include <linux/cpu.h>
+
+enum {
+	DEBUG_USER_STATE = 1U << 0,
+	DEBUG_SUSPEND = 1U << 2,
+	DEBUG_VERBOSE = 1U << 3,
+};
+static int debug_mask = DEBUG_USER_STATE;
+module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+static DEFINE_PER_CPU(int, tag);
+static struct work_struct cpu_up_work;
+static struct workqueue_struct *cpu_op_workqueue;
+
+
+static void earlysuspend_cpu_op(int cpu, bool status)
+{
+	/* tag the cpu is onling/offline */
+	if (status) {
+		per_cpu(tag, cpu) = 0;
+		cpu_up(cpu);
+	} else {
+		per_cpu(tag, cpu) = 1;
+		cpu_down(cpu);
+	}
+}
+
+static void cpuhotplug_early_suspend(struct early_suspend *p)
+{
+	int first_cpu, cpu;
+	/* skip the first cpu, cpu0 always online */
+	first_cpu = cpumask_first(cpu_online_mask);
+	for_each_possible_cpu(cpu) {
+		if (cpu == first_cpu)
+			continue;
+		if (cpu_online(cpu))
+			earlysuspend_cpu_op(cpu, false);
+	}
+}
+
+static void cpu_up_work_func(struct work_struct *work)
+{
+	int first_cpu, c;
+	/* skip the first cpu, cpu0 always online */
+	first_cpu = cpumask_first(cpu_online_mask);
+	for_each_possible_cpu(c) {
+		if (c == first_cpu)
+			continue;
+		if (debug_mask & DEBUG_SUSPEND)
+			pr_info(" %s: CPU%d tag %d\n", __func__, c,
+				       per_cpu(tag, c));
+		if (!cpu_online(c) && per_cpu(tag, c))
+			earlysuspend_cpu_op(c, true);
+	}
+}
+
+
+static void cpuhotplug_late_resume(struct early_suspend *p)
+{
+	if (debug_mask & DEBUG_SUSPEND)
+		pr_info(" %s: bootup secondary cpus\n", __func__);
+	queue_work(cpu_op_workqueue, &cpu_up_work);
+
+}
+
+struct early_suspend cpuhotplug_earlysuspend = {
+	.level = EARLY_SUSPEND_LEVEL_DISABLE_FB,
+	.suspend = cpuhotplug_early_suspend,
+	.resume = cpuhotplug_late_resume,
+};
+
+
+static int __init cpuhotplug_earlysuspend_init(void)
+{
+	cpu_op_workqueue = create_workqueue("cpu hotplug earlysuspend wq");
+	INIT_WORK(&cpu_up_work, cpu_up_work_func);
+
+	register_early_suspend(&cpuhotplug_earlysuspend);
+	return 0;
+}
+
+static void __exit cpuhotplug_earlysuspend_exit(void)
+{
+	if (NULL != cpu_op_workqueue)
+		destroy_workqueue(cpu_op_workqueue);
+	unregister_early_suspend(&cpuhotplug_earlysuspend);
+}
+
+module_init(cpuhotplug_earlysuspend_init);
+module_exit(cpuhotplug_earlysuspend_exit);
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");