4 files changed, 281 insertions, 2 deletions

diff --git a/drivers/base/power/opp/Makefile b/drivers/base/power/opp/Makefile
index 33c1e18c41a4..19837ef04d8e 100644
--- a/drivers/base/power/opp/Makefile
+++ b/drivers/base/power/opp/Makefile
@@ -1,2 +1,3 @@
 ccflags-$(CONFIG_DEBUG_DRIVER)  := -DDEBUG
 obj-y                           += core.o cpu.o
+obj-$(CONFIG_DEBUG_FS)          += debugfs.o
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index b8e76f75073b..6aa172be6e8e 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -463,6 +463,7 @@ static void _kfree_list_dev_rcu(struct rcu_head *head)
 static void _remove_list_dev(struct device_list_opp *list_dev,
                              struct device_opp *dev_opp)
 {
+        opp_debug_unregister(list_dev, dev_opp);
         list_del(&list_dev->node);
         call_srcu(&dev_opp->srcu_head.srcu, &list_dev->rcu_head,
                   _kfree_list_dev_rcu);
@@ -472,6 +473,7 @@ struct device_list_opp *_add_list_dev(const struct device *dev,
                                       struct device_opp *dev_opp)
 {
         struct device_list_opp *list_dev;
+        int ret;
 
         list_dev = kzalloc(sizeof(*list_dev), GFP_KERNEL);
         if (!list_dev)
@@ -481,6 +483,12 @@ struct device_list_opp *_add_list_dev(const struct device *dev,
         list_dev->dev = dev;
         list_add_rcu(&list_dev->node, &dev_opp->dev_list);
 
+        /* Create debugfs entries for the dev_opp */
+        ret = opp_debug_register(list_dev, dev_opp);
+        if (ret)
+                dev_err(dev, "%s: Failed to register opp debugfs (%d)\n",
+                        __func__, ret);
+
         return list_dev;
 }
 
@@ -596,6 +604,7 @@ static void _opp_remove(struct device_opp *dev_opp,
          */
         if (notify)
                 srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
+        opp_debug_remove_one(opp);
         list_del_rcu(&opp->node);
         call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
 
@@ -673,6 +682,7 @@ static int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
 {
         struct dev_pm_opp *opp;
         struct list_head *head = &dev_opp->opp_list;
+        int ret;
 
         /*
          * Insert new OPP in order of increasing frequency and discard if
@@ -703,6 +713,11 @@ static int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
         new_opp->dev_opp = dev_opp;
         list_add_rcu(&new_opp->node, head);
 
+        ret = opp_debug_create_one(new_opp, dev_opp);
+        if (ret)
+                dev_err(dev, "%s: Failed to register opp to debugfs (%d)\n",
+                        __func__, ret);
+
         return 0;
 }
 
@@ -889,12 +904,14 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
 
         /* OPP to select on device suspend */
         if (of_property_read_bool(np, "opp-suspend")) {
-                if (dev_opp->suspend_opp)
+                if (dev_opp->suspend_opp) {
                         dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
                                  __func__, dev_opp->suspend_opp->rate,
                                  new_opp->rate);
-                else
+                } else {
+                        new_opp->suspend = true;
                         dev_opp->suspend_opp = new_opp;
+                }
         }
 
         if (new_opp->clock_latency_ns > dev_opp->clock_latency_ns_max)
diff --git a/drivers/base/power/opp/debugfs.c b/drivers/base/power/opp/debugfs.c
new file mode 100644
index 000000000000..ddfe4773e922
--- /dev/null
+++ b/drivers/base/power/opp/debugfs.c
@@ -0,0 +1,219 @@
+/*
+ * Generic OPP debugfs interface
+ *
+ * Copyright (C) 2015-2016 Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/limits.h>
+
+#include "opp.h"
+
+static struct dentry *rootdir;
+
+static void opp_set_dev_name(const struct device *dev, char *name)
+{
+        if (dev->parent)
+                snprintf(name, NAME_MAX, "%s-%s", dev_name(dev->parent),
+                         dev_name(dev));
+        else
+                snprintf(name, NAME_MAX, "%s", dev_name(dev));
+}
+
+void opp_debug_remove_one(struct dev_pm_opp *opp)
+{
+        debugfs_remove_recursive(opp->dentry);
+}
+
+int opp_debug_create_one(struct dev_pm_opp *opp, struct device_opp *dev_opp)
+{
+        struct dentry *pdentry = dev_opp->dentry;
+        struct dentry *d;
+        char name[25];  /* 20 chars for 64 bit value + 5 (opp:\0) */
+
+        /* Rate is unique to each OPP, use it to give opp-name */
+        snprintf(name, sizeof(name), "opp:%lu", opp->rate);
+
+        /* Create per-opp directory */
+        d = debugfs_create_dir(name, pdentry);
+        if (!d)
+                return -ENOMEM;
+
+        if (!debugfs_create_bool("available", S_IRUGO, d, &opp->available))
+                return -ENOMEM;
+
+        if (!debugfs_create_bool("dynamic", S_IRUGO, d, &opp->dynamic))
+                return -ENOMEM;
+
+        if (!debugfs_create_bool("turbo", S_IRUGO, d, &opp->turbo))
+                return -ENOMEM;
+
+        if (!debugfs_create_bool("suspend", S_IRUGO, d, &opp->suspend))
+                return -ENOMEM;
+
+        if (!debugfs_create_ulong("rate_hz", S_IRUGO, d, &opp->rate))
+                return -ENOMEM;
+
+        if (!debugfs_create_ulong("u_volt_target", S_IRUGO, d, &opp->u_volt))
+                return -ENOMEM;
+
+        if (!debugfs_create_ulong("u_volt_min", S_IRUGO, d, &opp->u_volt_min))
+                return -ENOMEM;
+
+        if (!debugfs_create_ulong("u_volt_max", S_IRUGO, d, &opp->u_volt_max))
+                return -ENOMEM;
+
+        if (!debugfs_create_ulong("u_amp", S_IRUGO, d, &opp->u_amp))
+                return -ENOMEM;
+
+        if (!debugfs_create_ulong("clock_latency_ns", S_IRUGO, d,
+                                  &opp->clock_latency_ns))
+                return -ENOMEM;
+
+        opp->dentry = d;
+        return 0;
+}
+
+static int device_opp_debug_create_dir(struct device_list_opp *list_dev,
+                                       struct device_opp *dev_opp)
+{
+        const struct device *dev = list_dev->dev;
+        struct dentry *d;
+
+        opp_set_dev_name(dev, dev_opp->dentry_name);
+
+        /* Create device specific directory */
+        d = debugfs_create_dir(dev_opp->dentry_name, rootdir);
+        if (!d) {
+                dev_err(dev, "%s: Failed to create debugfs dir\n", __func__);
+                return -ENOMEM;
+        }
+
+        list_dev->dentry = d;
+        dev_opp->dentry = d;
+
+        return 0;
+}
+
+static int device_opp_debug_create_link(struct device_list_opp *list_dev,
+                                        struct device_opp *dev_opp)
+{
+        const struct device *dev = list_dev->dev;
+        char name[NAME_MAX];
+        struct dentry *d;
+
+        opp_set_dev_name(list_dev->dev, name);
+
+        /* Create device specific directory link */
+        d = debugfs_create_symlink(name, rootdir, dev_opp->dentry_name);
+        if (!d) {
+                dev_err(dev, "%s: Failed to create link\n", __func__);
+                return -ENOMEM;
+        }
+
+        list_dev->dentry = d;
+
+        return 0;
+}
+
+/**
+ * opp_debug_register - add a device opp node to the debugfs 'opp' directory
+ * @list_dev: list-dev pointer for device
+ * @dev_opp: the device-opp being added
+ *
+ * Dynamically adds device specific directory in debugfs 'opp' directory. If the
+ * device-opp is shared with other devices, then links will be created for all
+ * devices except the first.
+ *
+ * Return: 0 on success, otherwise negative error.
+ */
+int opp_debug_register(struct device_list_opp *list_dev,
+                       struct device_opp *dev_opp)
+{
+        if (!rootdir) {
+                pr_debug("%s: Uninitialized rootdir\n", __func__);
+                return -EINVAL;
+        }
+
+        if (dev_opp->dentry)
+                return device_opp_debug_create_link(list_dev, dev_opp);
+
+        return device_opp_debug_create_dir(list_dev, dev_opp);
+}
+
+static void opp_migrate_dentry(struct device_list_opp *list_dev,
+                               struct device_opp *dev_opp)
+{
+        struct device_list_opp *new_dev;
+        const struct device *dev;
+        struct dentry *dentry;
+
+        /* Look for next list-dev */
+        list_for_each_entry(new_dev, &dev_opp->dev_list, node)
+                if (new_dev != list_dev)
+                        break;
+
+        /* new_dev is guaranteed to be valid here */
+        dev = new_dev->dev;
+        debugfs_remove_recursive(new_dev->dentry);
+
+        opp_set_dev_name(dev, dev_opp->dentry_name);
+
+        dentry = debugfs_rename(rootdir, list_dev->dentry, rootdir,
+                                dev_opp->dentry_name);
+        if (!dentry) {
+                dev_err(dev, "%s: Failed to rename link from: %s to %s\n",
+                        __func__, dev_name(list_dev->dev), dev_name(dev));
+                return;
+        }
+
+        new_dev->dentry = dentry;
+        dev_opp->dentry = dentry;
+}
+
+/**
+ * opp_debug_unregister - remove a device opp node from debugfs opp directory
+ * @list_dev: list-dev pointer for device
+ * @dev_opp: the device-opp being removed
+ *
+ * Dynamically removes device specific directory from debugfs 'opp' directory.
+ */
+void opp_debug_unregister(struct device_list_opp *list_dev,
+                          struct device_opp *dev_opp)
+{
+        if (list_dev->dentry == dev_opp->dentry) {
+                /* Move the real dentry object under another device */
+                if (!list_is_singular(&dev_opp->dev_list)) {
+                        opp_migrate_dentry(list_dev, dev_opp);
+                        goto out;
+                }
+                dev_opp->dentry = NULL;
+        }
+
+        debugfs_remove_recursive(list_dev->dentry);
+
+out:
+        list_dev->dentry = NULL;
+}
+
+static int __init opp_debug_init(void)
+{
+        /* Create /sys/kernel/debug/opp directory */
+        rootdir = debugfs_create_dir("opp", NULL);
+        if (!rootdir) {
+                pr_err("%s: Failed to create root directory\n", __func__);
+                return -ENOMEM;
+        }
+
+        return 0;
+}
+core_initcall(opp_debug_init);
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index 7366b2aa8997..a6bd8d2c2b47 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -17,6 +17,7 @@
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
+#include <linux/limits.h>
 #include <linux/pm_opp.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
@@ -53,6 +54,7 @@ extern struct mutex dev_opp_list_lock;
  * @dynamic:    not-created from static DT entries.
  * @available:  true/false - marks if this OPP as available or not
  * @turbo:      true if turbo (boost) OPP
+ * @suspend:    true if suspend OPP
  * @rate:       Frequency in hertz
  * @u_volt:     Target voltage in microvolts corresponding to this OPP
  * @u_volt_min: Minimum voltage in microvolts corresponding to this OPP
@@ -63,6 +65,7 @@ extern struct mutex dev_opp_list_lock;
  * @dev_opp:    points back to the device_opp struct this opp belongs to
  * @rcu_head:   RCU callback head used for deferred freeing
  * @np:         OPP's device node.
+ * @dentry:     debugfs dentry pointer (per opp)
  *
  * This structure stores the OPP information for a given device.
  */
@@ -72,6 +75,7 @@ struct dev_pm_opp {
         bool available;
         bool dynamic;
         bool turbo;
+        bool suspend;
         unsigned long rate;
 
         unsigned long u_volt;
@@ -84,6 +88,10 @@ struct dev_pm_opp {
         struct rcu_head rcu_head;
 
         struct device_node *np;
+
+#ifdef CONFIG_DEBUG_FS
+        struct dentry *dentry;
+#endif
 };
 
 /**
@@ -91,6 +99,7 @@ struct dev_pm_opp {
  * @node:       list node
  * @dev:        device to which the struct object belongs
  * @rcu_head:   RCU callback head used for deferred freeing
+ * @dentry:     debugfs dentry pointer (per device)
  *
  * This is an internal data structure maintaining the list of devices that are
  * managed by 'struct device_opp'.
@@ -99,6 +108,10 @@ struct device_list_opp {
         struct list_head node;
         const struct device *dev;
         struct rcu_head rcu_head;
+
+#ifdef CONFIG_DEBUG_FS
+        struct dentry *dentry;
+#endif
 };
 
 /**
@@ -114,6 +127,8 @@ struct device_list_opp {
  * @opp_list:   list of opps
  * @np:         struct device_node pointer for opp's DT node.
  * @shared_opp: OPP is shared between multiple devices.
+ * @dentry:     debugfs dentry pointer of the real device directory (not links).
+ * @dentry_name: Name of the real dentry.
  *
  * This is an internal data structure maintaining the link to opps attached to
  * a device. This structure is not meant to be shared to users as it is
@@ -135,6 +150,11 @@ struct device_opp {
         unsigned long clock_latency_ns_max;
         bool shared_opp;
         struct dev_pm_opp *suspend_opp;
+
+#ifdef CONFIG_DEBUG_FS
+        struct dentry *dentry;
+        char dentry_name[NAME_MAX];
+#endif
 };
 
 /* Routines internal to opp core */
@@ -143,4 +163,26 @@ struct device_list_opp *_add_list_dev(const struct device *dev,
                                       struct device_opp *dev_opp);
 struct device_node *_of_get_opp_desc_node(struct device *dev);
 
+#ifdef CONFIG_DEBUG_FS
+void opp_debug_remove_one(struct dev_pm_opp *opp);
+int opp_debug_create_one(struct dev_pm_opp *opp, struct device_opp *dev_opp);
+int opp_debug_register(struct device_list_opp *list_dev,
+                       struct device_opp *dev_opp);
+void opp_debug_unregister(struct device_list_opp *list_dev,
+                          struct device_opp *dev_opp);
+#else
+static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
+
+static inline int opp_debug_create_one(struct dev_pm_opp *opp,
+                                       struct device_opp *dev_opp)
+{ return 0; }
+static inline int opp_debug_register(struct device_list_opp *list_dev,
+                                     struct device_opp *dev_opp)
+{ return 0; }
+
+static inline void opp_debug_unregister(struct device_list_opp *list_dev,
+                                        struct device_opp *dev_opp)
+{ }
+#endif          /* DEBUG_FS */
+
 #endif          /* __DRIVER_OPP_H__ */