cpuquiet: governor support

Change-Id: I05b9dedc04bb3b2ddba6202a002c1e5514ec4777
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-on: http://git-master/r/105269
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Tested-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>
Rebase-Id: R481f3df7610b737f6c054370efbe3bdb95a5e78d

diff --git a/drivers/cpuquiet/governor.c b/drivers/cpuquiet/governor.c
new file mode 100644 (file)
index 0000000..1446b9e
--- /dev/null
+++ b/drivers/cpuquiet/governor.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2012 NVIDIA CORPORATION.  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 as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ */
+
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/cpuquiet.h>
+
+#include "cpuquiet.h"
+
+LIST_HEAD(cpuquiet_governors);
+struct cpuquiet_governor *cpuquiet_curr_governor;
+
+struct cpuquiet_governor *cpuquiet_get_first_governor(void)
+{
+       if (!list_empty(&cpuquiet_governors))
+               return list_entry(&cpuquiet_governors, struct cpuquiet_governor,
+                                       governor_list);
+       else
+               return NULL;
+}
+
+struct cpuquiet_governor *cpuquiet_find_governor(const char *str)
+{
+       struct cpuquiet_governor *gov;
+
+       list_for_each_entry(gov, &cpuquiet_governors, governor_list)
+               if (!strnicmp(str, gov->name, CPUQUIET_NAME_LEN))
+                       return gov;
+
+       return NULL;
+}
+
+int cpuquiet_switch_governor(struct cpuquiet_governor *gov)
+{
+       int err = 0;
+
+       if (cpuquiet_curr_governor) {
+               if (cpuquiet_curr_governor->stop)
+                       cpuquiet_curr_governor->stop();
+               module_put(cpuquiet_curr_governor->owner);
+       }
+
+       cpuquiet_curr_governor = gov;
+
+       if (gov) {
+               if (!try_module_get(cpuquiet_curr_governor->owner))
+                       return -EINVAL;
+               if (gov->start)
+                       err = gov->start();
+               if (!err)
+                       cpuquiet_curr_governor = gov;
+       }
+
+       return err;
+}
+
+int cpuquiet_register_governor(struct cpuquiet_governor *gov)
+{
+       int ret = -EEXIST;
+
+       if (!gov)
+               return -EINVAL;
+
+       mutex_lock(&cpuquiet_lock);
+       if (cpuquiet_find_governor(gov->name) == NULL) {
+               ret = 0;
+               list_add_tail(&gov->governor_list, &cpuquiet_governors);
+               if (!cpuquiet_curr_governor && cpuquiet_get_driver())
+                       cpuquiet_switch_governor(gov);
+       }
+       mutex_unlock(&cpuquiet_lock);
+
+       return ret;
+}
+
+void cpuquiet_unregister_governor(struct cpuquiet_governor *gov)
+{
+       if (!gov)
+               return;
+
+       mutex_lock(&cpuquiet_lock);
+       if (cpuquiet_curr_governor == gov)
+               cpuquiet_switch_governor(NULL);
+       list_del(&gov->governor_list);
+       mutex_unlock(&cpuquiet_lock);
+}