1 files changed, 425 insertions, 0 deletions

diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
new file mode 100644
index 000000000000..0afe32be4c85
--- /dev/null
+++ b/kernel/pm_qos_params.c
@@ -0,0 +1,425 @@
+/*
+ * This module exposes the interface to kernel space for specifying
+ * QoS dependencies.  It provides infrastructure for registration of:
+ *
+ * Dependents on a QoS value : register requirements
+ * Watchers of QoS value : get notified when target QoS value changes
+ *
+ * This QoS design is best effort based.  Dependents register their QoS needs.
+ * Watchers register to keep track of the current QoS needs of the system.
+ *
+ * There are 3 basic classes of QoS parameter: latency, timeout, throughput
+ * each have defined units:
+ * latency: usec
+ * timeout: usec <-- currently not used.
+ * throughput: kbs (kilo byte / sec)
+ *
+ * There are lists of pm_qos_objects each one wrapping requirements, notifiers
+ *
+ * User mode requirements on a QOS parameter register themselves to the
+ * subsystem by opening the device node /dev/... and writing there request to
+ * the node.  As long as the process holds a file handle open to the node the
+ * client continues to be accounted for.  Upon file release the usermode
+ * requirement is removed and a new qos target is computed.  This way when the
+ * requirement that the application has is cleaned up when closes the file
+ * pointer or exits the pm_qos_object will get an opportunity to clean up.
+ *
+ * mark gross mgross@linux.intel.com
+ */
+
+#include <linux/pm_qos_params.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+
+#include <linux/uaccess.h>
+
+/*
+ * locking rule: all changes to target_value or requirements or notifiers lists
+ * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
+ * held, taken with _irqsave.  One lock to rule them all
+ */
+struct requirement_list {
+        struct list_head list;
+        union {
+                s32 value;
+                s32 usec;
+                s32 kbps;
+        };
+        char *name;
+};
+
+static s32 max_compare(s32 v1, s32 v2);
+static s32 min_compare(s32 v1, s32 v2);
+
+struct pm_qos_object {
+        struct requirement_list requirements;
+        struct blocking_notifier_head *notifiers;
+        struct miscdevice pm_qos_power_miscdev;
+        char *name;
+        s32 default_value;
+        s32 target_value;
+        s32 (*comparitor)(s32, s32);
+};
+
+static struct pm_qos_object null_pm_qos;
+static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
+static struct pm_qos_object cpu_dma_pm_qos = {
+        .requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
+        .notifiers = &cpu_dma_lat_notifier,
+        .name = "cpu_dma_latency",
+        .default_value = 2000 * USEC_PER_SEC,
+        .target_value = 2000 * USEC_PER_SEC,
+        .comparitor = min_compare
+};
+
+static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
+static struct pm_qos_object network_lat_pm_qos = {
+        .requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
+        .notifiers = &network_lat_notifier,
+        .name = "network_latency",
+        .default_value = 2000 * USEC_PER_SEC,
+        .target_value = 2000 * USEC_PER_SEC,
+        .comparitor = min_compare
+};
+
+
+static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
+static struct pm_qos_object network_throughput_pm_qos = {
+        .requirements =
+                {LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
+        .notifiers = &network_throughput_notifier,
+        .name = "network_throughput",
+        .default_value = 0,
+        .target_value = 0,
+        .comparitor = max_compare
+};
+
+
+static struct pm_qos_object *pm_qos_array[] = {
+        &null_pm_qos,
+        &cpu_dma_pm_qos,
+        &network_lat_pm_qos,
+        &network_throughput_pm_qos
+};
+
+static DEFINE_SPINLOCK(pm_qos_lock);
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+                size_t count, loff_t *f_pos);
+static int pm_qos_power_open(struct inode *inode, struct file *filp);
+static int pm_qos_power_release(struct inode *inode, struct file *filp);
+
+static const struct file_operations pm_qos_power_fops = {
+        .write = pm_qos_power_write,
+        .open = pm_qos_power_open,
+        .release = pm_qos_power_release,
+};
+
+/* static helper functions */
+static s32 max_compare(s32 v1, s32 v2)
+{
+        return max(v1, v2);
+}
+
+static s32 min_compare(s32 v1, s32 v2)
+{
+        return min(v1, v2);
+}
+
+
+static void update_target(int target)
+{
+        s32 extreme_value;
+        struct requirement_list *node;
+        unsigned long flags;
+        int call_notifier = 0;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        extreme_value = pm_qos_array[target]->default_value;
+        list_for_each_entry(node,
+                        &pm_qos_array[target]->requirements.list, list) {
+                extreme_value = pm_qos_array[target]->comparitor(
+                                extreme_value, node->value);
+        }
+        if (pm_qos_array[target]->target_value != extreme_value) {
+                call_notifier = 1;
+                pm_qos_array[target]->target_value = extreme_value;
+                pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
+                        pm_qos_array[target]->target_value);
+        }
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+        if (call_notifier)
+                blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
+                        (unsigned long) extreme_value, NULL);
+}
+
+static int register_pm_qos_misc(struct pm_qos_object *qos)
+{
+        qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
+        qos->pm_qos_power_miscdev.name = qos->name;
+        qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
+
+        return misc_register(&qos->pm_qos_power_miscdev);
+}
+
+static int find_pm_qos_object_by_minor(int minor)
+{
+        int pm_qos_class;
+
+        for (pm_qos_class = 0;
+                pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
+                if (minor ==
+                        pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
+                        return pm_qos_class;
+        }
+        return -1;
+}
+
+/**
+ * pm_qos_requirement - returns current system wide qos expectation
+ * @pm_qos_class: identification of which qos value is requested
+ *
+ * This function returns the current target value in an atomic manner.
+ */
+int pm_qos_requirement(int pm_qos_class)
+{
+        int ret_val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        ret_val = pm_qos_array[pm_qos_class]->target_value;
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+        return ret_val;
+}
+EXPORT_SYMBOL_GPL(pm_qos_requirement);
+
+/**
+ * pm_qos_add_requirement - inserts new qos request into the list
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * This function inserts a new entry in the pm_qos_class list of requested qos
+ * performance charactoistics.  It recomputes the agregate QoS expectations for
+ * the pm_qos_class of parrameters.
+ */
+int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
+{
+        struct requirement_list *dep;
+        unsigned long flags;
+
+        dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
+        if (dep) {
+                if (value == PM_QOS_DEFAULT_VALUE)
+                        dep->value = pm_qos_array[pm_qos_class]->default_value;
+                else
+                        dep->value = value;
+                dep->name = kstrdup(name, GFP_KERNEL);
+                if (!dep->name)
+                        goto cleanup;
+
+                spin_lock_irqsave(&pm_qos_lock, flags);
+                list_add(&dep->list,
+                        &pm_qos_array[pm_qos_class]->requirements.list);
+                spin_unlock_irqrestore(&pm_qos_lock, flags);
+                update_target(pm_qos_class);
+
+                return 0;
+        }
+
+cleanup:
+        kfree(dep);
+        return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
+
+/**
+ * pm_qos_update_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * Updates an existing qos requierement for the pm_qos_class of parameters along
+ * with updating the target pm_qos_class value.
+ *
+ * If the named request isn't in the lest then no change is made.
+ */
+int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
+{
+        unsigned long flags;
+        struct requirement_list *node;
+        int pending_update = 0;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        list_for_each_entry(node,
+                &pm_qos_array[pm_qos_class]->requirements.list, list) {
+                if (strcmp(node->name, name) == 0) {
+                        if (new_value == PM_QOS_DEFAULT_VALUE)
+                                node->value =
+                                pm_qos_array[pm_qos_class]->default_value;
+                        else
+                                node->value = new_value;
+                        pending_update = 1;
+                        break;
+                }
+        }
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+        if (pending_update)
+                update_target(pm_qos_class);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
+
+/**
+ * pm_qos_remove_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ *
+ * Will remove named qos request from pm_qos_class list of parrameters and
+ * recompute the current target value for the pm_qos_class.
+ */
+void pm_qos_remove_requirement(int pm_qos_class, char *name)
+{
+        unsigned long flags;
+        struct requirement_list *node;
+        int pending_update = 0;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        list_for_each_entry(node,
+                &pm_qos_array[pm_qos_class]->requirements.list, list) {
+                if (strcmp(node->name, name) == 0) {
+                        kfree(node->name);
+                        list_del(&node->list);
+                        kfree(node);
+                        pending_update = 1;
+                        break;
+                }
+        }
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+        if (pending_update)
+                update_target(pm_qos_class);
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
+
+/**
+ * pm_qos_add_notifier - sets notification entry for changes to target value
+ * @pm_qos_class: identifies which qos target changes should be notified.
+ * @notifier: notifier block managed by caller.
+ *
+ * will register the notifier into a notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+        int retval;
+
+        retval = blocking_notifier_chain_register(
+                        pm_qos_array[pm_qos_class]->notifiers, notifier);
+
+        return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
+
+/**
+ * pm_qos_remove_notifier - deletes notification entry from chain.
+ * @pm_qos_class: identifies which qos target changes are notified.
+ * @notifier: notifier block to be removed.
+ *
+ * will remove the notifier from the notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+        int retval;
+
+        retval = blocking_notifier_chain_unregister(
+                        pm_qos_array[pm_qos_class]->notifiers, notifier);
+
+        return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
+
+#define PID_NAME_LEN sizeof("process_1234567890")
+static char name[PID_NAME_LEN];
+
+static int pm_qos_power_open(struct inode *inode, struct file *filp)
+{
+        int ret;
+        long pm_qos_class;
+
+        pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
+        if (pm_qos_class >= 0) {
+                filp->private_data = (void *)pm_qos_class;
+                sprintf(name, "process_%d", current->pid);
+                ret = pm_qos_add_requirement(pm_qos_class, name,
+                                        PM_QOS_DEFAULT_VALUE);
+                if (ret >= 0)
+                        return 0;
+        }
+
+        return -EPERM;
+}
+
+static int pm_qos_power_release(struct inode *inode, struct file *filp)
+{
+        int pm_qos_class;
+
+        pm_qos_class = (long)filp->private_data;
+        sprintf(name, "process_%d", current->pid);
+        pm_qos_remove_requirement(pm_qos_class, name);
+
+        return 0;
+}
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+                size_t count, loff_t *f_pos)
+{
+        s32 value;
+        int pm_qos_class;
+
+        pm_qos_class = (long)filp->private_data;
+        if (count != sizeof(s32))
+                return -EINVAL;
+        if (copy_from_user(&value, buf, sizeof(s32)))
+                return -EFAULT;
+        sprintf(name, "process_%d", current->pid);
+        pm_qos_update_requirement(pm_qos_class, name, value);
+
+        return  sizeof(s32);
+}
+
+
+static int __init pm_qos_power_init(void)
+{
+        int ret = 0;
+
+        ret = register_pm_qos_misc(&cpu_dma_pm_qos);
+        if (ret < 0) {
+                printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
+                return ret;
+        }
+        ret = register_pm_qos_misc(&network_lat_pm_qos);
+        if (ret < 0) {
+                printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
+                return ret;
+        }
+        ret = register_pm_qos_misc(&network_throughput_pm_qos);
+        if (ret < 0)
+                printk(KERN_ERR
+                        "pm_qos_param: network_throughput setup failed\n");
+
+        return ret;
+}
+
+late_initcall(pm_qos_power_init);