| /* |
| * 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/smp_lock.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; |
| |
| lock_kernel(); |
| 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) { |
| unlock_kernel(); |
| return 0; |
| } |
| } |
| unlock_kernel(); |
| |
| 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); |