powerpc/fsl: add MPIC timer wakeup support

The driver provides a way to wake up the system by the MPIC timer.

For example,
echo 5 > /sys/devices/system/mpic/timer_wakeup
echo standby > /sys/power/state

After 5 seconds the MPIC timer will generate an interrupt to wake up
the system.

Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>

3 files changed, 171 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 7d07d9e8e1dd..0847ee6cd616 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -98,6 +98,15 @@ config MPIC_TIMER
           chip, but it can potentially support other global timers
           complying with the OpenPIC standard.
 
+config FSL_MPIC_TIMER_WAKEUP
+        tristate "Freescale MPIC global timer wakeup driver"
+        depends on FSL_SOC &&  MPIC_TIMER && PM
+        default n
+        help
+          The driver provides a way to wake up the system by MPIC
+          timer.
+          e.g. "echo 5 > /sys/devices/system/mpic/timer_wakeup"
+
 config PPC_EPAPR_HV_PIC
         bool
         default n
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index 2eb72c1a4291..f67ac900d870 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -5,6 +5,7 @@ ccflags-$(CONFIG_PPC64)		:= $(NO_MINIMAL_TOC)
 mpic-msi-obj-$(CONFIG_PCI_MSI)  += mpic_msi.o mpic_u3msi.o mpic_pasemi_msi.o
 obj-$(CONFIG_MPIC)              += mpic.o $(mpic-msi-obj-y)
 obj-$(CONFIG_MPIC_TIMER)        += mpic_timer.o
+obj-$(CONFIG_FSL_MPIC_TIMER_WAKEUP)     += fsl_mpic_timer_wakeup.o
 mpic-msgr-obj-$(CONFIG_MPIC_MSGR)       += mpic_msgr.o
 obj-$(CONFIG_MPIC)              += mpic.o $(mpic-msi-obj-y) $(mpic-msgr-obj-y)
 obj-$(CONFIG_PPC_EPAPR_HV_PIC)  += ehv_pic.o
diff --git a/arch/powerpc/sysdev/fsl_mpic_timer_wakeup.c b/arch/powerpc/sysdev/fsl_mpic_timer_wakeup.c
new file mode 100644
index 000000000000..1707bf04dec6
--- /dev/null
+++ b/arch/powerpc/sysdev/fsl_mpic_timer_wakeup.c
@@ -0,0 +1,161 @@
+/*
+ * MPIC timer wakeup driver
+ *
+ * Copyright 2013 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+
+#include <asm/mpic_timer.h>
+#include <asm/mpic.h>
+
+struct fsl_mpic_timer_wakeup {
+        struct mpic_timer *timer;
+        struct work_struct free_work;
+};
+
+static struct fsl_mpic_timer_wakeup *fsl_wakeup;
+static DEFINE_MUTEX(sysfs_lock);
+
+static void fsl_free_resource(struct work_struct *ws)
+{
+        struct fsl_mpic_timer_wakeup *wakeup =
+                container_of(ws, struct fsl_mpic_timer_wakeup, free_work);
+
+        mutex_lock(&sysfs_lock);
+
+        if (wakeup->timer) {
+                disable_irq_wake(wakeup->timer->irq);
+                mpic_free_timer(wakeup->timer);
+        }
+
+        wakeup->timer = NULL;
+        mutex_unlock(&sysfs_lock);
+}
+
+static irqreturn_t fsl_mpic_timer_irq(int irq, void *dev_id)
+{
+        struct fsl_mpic_timer_wakeup *wakeup = dev_id;
+
+        schedule_work(&wakeup->free_work);
+
+        return wakeup->timer ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static ssize_t fsl_timer_wakeup_show(struct device *dev,
+                                struct device_attribute *attr,
+                                char *buf)
+{
+        struct timeval interval;
+        int val = 0;
+
+        mutex_lock(&sysfs_lock);
+        if (fsl_wakeup->timer) {
+                mpic_get_remain_time(fsl_wakeup->timer, &interval);
+                val = interval.tv_sec + 1;
+        }
+        mutex_unlock(&sysfs_lock);
+
+        return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t fsl_timer_wakeup_store(struct device *dev,
+                                struct device_attribute *attr,
+                                const char *buf,
+                                size_t count)
+{
+        struct timeval interval;
+        int ret;
+
+        interval.tv_usec = 0;
+        if (kstrtol(buf, 0, &interval.tv_sec))
+                return -EINVAL;
+
+        mutex_lock(&sysfs_lock);
+
+        if (fsl_wakeup->timer) {
+                disable_irq_wake(fsl_wakeup->timer->irq);
+                mpic_free_timer(fsl_wakeup->timer);
+                fsl_wakeup->timer = NULL;
+        }
+
+        if (!interval.tv_sec) {
+                mutex_unlock(&sysfs_lock);
+                return count;
+        }
+
+        fsl_wakeup->timer = mpic_request_timer(fsl_mpic_timer_irq,
+                                                fsl_wakeup, &interval);
+        if (!fsl_wakeup->timer) {
+                mutex_unlock(&sysfs_lock);
+                return -EINVAL;
+        }
+
+        ret = enable_irq_wake(fsl_wakeup->timer->irq);
+        if (ret) {
+                mpic_free_timer(fsl_wakeup->timer);
+                fsl_wakeup->timer = NULL;
+                mutex_unlock(&sysfs_lock);
+
+                return ret;
+        }
+
+        mpic_start_timer(fsl_wakeup->timer);
+
+        mutex_unlock(&sysfs_lock);
+
+        return count;
+}
+
+static struct device_attribute mpic_attributes = __ATTR(timer_wakeup, 0644,
+                        fsl_timer_wakeup_show, fsl_timer_wakeup_store);
+
+static int __init fsl_wakeup_sys_init(void)
+{
+        int ret;
+
+        fsl_wakeup = kzalloc(sizeof(struct fsl_mpic_timer_wakeup), GFP_KERNEL);
+        if (!fsl_wakeup)
+                return -ENOMEM;
+
+        INIT_WORK(&fsl_wakeup->free_work, fsl_free_resource);
+
+        ret = device_create_file(mpic_subsys.dev_root, &mpic_attributes);
+        if (ret)
+                kfree(fsl_wakeup);
+
+        return ret;
+}
+
+static void __exit fsl_wakeup_sys_exit(void)
+{
+        device_remove_file(mpic_subsys.dev_root, &mpic_attributes);
+
+        mutex_lock(&sysfs_lock);
+
+        if (fsl_wakeup->timer) {
+                disable_irq_wake(fsl_wakeup->timer->irq);
+                mpic_free_timer(fsl_wakeup->timer);
+        }
+
+        kfree(fsl_wakeup);
+
+        mutex_unlock(&sysfs_lock);
+}
+
+module_init(fsl_wakeup_sys_init);
+module_exit(fsl_wakeup_sys_exit);
+
+MODULE_DESCRIPTION("Freescale MPIC global timer wakeup driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Wang Dongsheng <dongsheng.wang@freescale.com>");