thermal: Add event notification to thermal framework

This patch adds event notification support to the generic
thermal sysfs framework in the kernel. The notification is in the
form of a netlink event.

Signed-off-by: R.Durgadoss <durgadoss.r@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 103 insertions, 1 deletions

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index bf7c687519e..f7a5dba3ca2 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -4,6 +4,7 @@
 
 menuconfig THERMAL
         tristate "Generic Thermal sysfs driver"
+        depends on NET
         help
           Generic Thermal Sysfs driver offers a generic mechanism for
           thermal management. Usually it's made up of one or more thermal
diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 13c72c62932..760e045c93c 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -32,6 +32,8 @@
 #include <linux/thermal.h>
 #include <linux/spinlock.h>
 #include <linux/reboot.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
 
 MODULE_AUTHOR("Zhang Rui");
 MODULE_DESCRIPTION("Generic thermal management sysfs support");
@@ -58,6 +60,22 @@ static LIST_HEAD(thermal_tz_list);
 static LIST_HEAD(thermal_cdev_list);
 static DEFINE_MUTEX(thermal_list_lock);
 
+static unsigned int thermal_event_seqnum;
+
+static struct genl_family thermal_event_genl_family = {
+        .id = GENL_ID_GENERATE,
+        .name = THERMAL_GENL_FAMILY_NAME,
+        .version = THERMAL_GENL_VERSION,
+        .maxattr = THERMAL_GENL_ATTR_MAX,
+};
+
+static struct genl_multicast_group thermal_event_mcgrp = {
+        .name = THERMAL_GENL_MCAST_GROUP_NAME,
+};
+
+static int genetlink_init(void);
+static void genetlink_exit(void);
+
 static int get_idr(struct idr *idr, struct mutex *lock, int *id)
 {
         int err;
@@ -1214,6 +1232,82 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz)
 
 EXPORT_SYMBOL(thermal_zone_device_unregister);
 
+int generate_netlink_event(u32 orig, enum events event)
+{
+        struct sk_buff *skb;
+        struct nlattr *attr;
+        struct thermal_genl_event *thermal_event;
+        void *msg_header;
+        int size;
+        int result;
+
+        /* allocate memory */
+        size = nla_total_size(sizeof(struct thermal_genl_event)) + \
+                                nla_total_size(0);
+
+        skb = genlmsg_new(size, GFP_ATOMIC);
+        if (!skb)
+                return -ENOMEM;
+
+        /* add the genetlink message header */
+        msg_header = genlmsg_put(skb, 0, thermal_event_seqnum++,
+                                 &thermal_event_genl_family, 0,
+                                 THERMAL_GENL_CMD_EVENT);
+        if (!msg_header) {
+                nlmsg_free(skb);
+                return -ENOMEM;
+        }
+
+        /* fill the data */
+        attr = nla_reserve(skb, THERMAL_GENL_ATTR_EVENT, \
+                        sizeof(struct thermal_genl_event));
+
+        if (!attr) {
+                nlmsg_free(skb);
+                return -EINVAL;
+        }
+
+        thermal_event = nla_data(attr);
+        if (!thermal_event) {
+                nlmsg_free(skb);
+                return -EINVAL;
+        }
+
+        memset(thermal_event, 0, sizeof(struct thermal_genl_event));
+
+        thermal_event->orig = orig;
+        thermal_event->event = event;
+
+        /* send multicast genetlink message */
+        result = genlmsg_end(skb, msg_header);
+        if (result < 0) {
+                nlmsg_free(skb);
+                return result;
+        }
+
+        result = genlmsg_multicast(skb, 0, thermal_event_mcgrp.id, GFP_ATOMIC);
+        if (result)
+                printk(KERN_INFO "failed to send netlink event:%d", result);
+
+        return result;
+}
+EXPORT_SYMBOL(generate_netlink_event);
+
+static int genetlink_init(void)
+{
+        int result;
+
+        result = genl_register_family(&thermal_event_genl_family);
+        if (result)
+                return result;
+
+        result = genl_register_mc_group(&thermal_event_genl_family,
+                                        &thermal_event_mcgrp);
+        if (result)
+                genl_unregister_family(&thermal_event_genl_family);
+        return result;
+}
+
 static int __init thermal_init(void)
 {
         int result = 0;
@@ -1225,9 +1319,15 @@ static int __init thermal_init(void)
                 mutex_destroy(&thermal_idr_lock);
                 mutex_destroy(&thermal_list_lock);
         }
+        result = genetlink_init();
         return result;
 }
 
+static void genetlink_exit(void)
+{
+        genl_unregister_family(&thermal_event_genl_family);
+}
+
 static void __exit thermal_exit(void)
 {
         class_unregister(&thermal_class);
@@ -1235,7 +1335,8 @@ static void __exit thermal_exit(void)
         idr_destroy(&thermal_cdev_idr);
         mutex_destroy(&thermal_idr_lock);
         mutex_destroy(&thermal_list_lock);
+        genetlink_exit();
 }
 
-subsys_initcall(thermal_init);
+fs_initcall(thermal_init);
 module_exit(thermal_exit);