diff options
Diffstat (limited to 'drivers/misc/memory_state_time.c')
| -rw-r--r-- | drivers/misc/memory_state_time.c | 454 |
1 files changed, 454 insertions, 0 deletions
diff --git a/drivers/misc/memory_state_time.c b/drivers/misc/memory_state_time.c new file mode 100644 index 000000000000..34c797a06a31 --- /dev/null +++ b/drivers/misc/memory_state_time.c @@ -0,0 +1,454 @@ +/* drivers/misc/memory_state_time.c + * + * Copyright (C) 2016 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * 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. + * + */ + +#include <linux/device.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/hashtable.h> +#include <linux/kconfig.h> +#include <linux/kernel.h> +#include <linux/kobject.h> +#include <linux/memory-state-time.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of_platform.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/time.h> +#include <linux/timekeeping.h> +#include <linux/workqueue.h> + +#define KERNEL_ATTR_RO(_name) \ +static struct kobj_attribute _name##_attr = __ATTR_RO(_name) + +#define KERNEL_ATTR_RW(_name) \ +static struct kobj_attribute _name##_attr = \ + __ATTR(_name, 0644, _name##_show, _name##_store) + +#define FREQ_HASH_BITS 4 +DECLARE_HASHTABLE(freq_hash_table, FREQ_HASH_BITS); + +static DEFINE_MUTEX(mem_lock); + +#define TAG "memory_state_time" +#define BW_NODE "/soc/memory-state-time" +#define FREQ_TBL "freq-tbl" +#define BW_TBL "bw-buckets" +#define NUM_SOURCES "num-sources" + +#define LOWEST_FREQ 2 + +static int curr_bw; +static int curr_freq; +static u32 *bw_buckets; +static u32 *freq_buckets; +static int num_freqs; +static int num_buckets; +static int registered_bw_sources; +static u64 last_update; +static bool init_success; +static struct workqueue_struct *memory_wq; +static u32 num_sources = 10; +static int *bandwidths; + +struct freq_entry { + int freq; + u64 *buckets; /* Bandwidth buckets. */ + struct hlist_node hash; +}; + +struct queue_container { + struct work_struct update_state; + int value; + u64 time_now; + int id; + struct mutex *lock; +}; + +static int find_bucket(int bw) +{ + int i; + + if (bw_buckets != NULL) { + for (i = 0; i < num_buckets; i++) { + if (bw_buckets[i] > bw) { + pr_debug("Found bucket %d for bandwidth %d\n", + i, bw); + return i; + } + } + return num_buckets - 1; + } + return 0; +} + +static u64 get_time_diff(u64 time_now) +{ + u64 ms; + + ms = time_now - last_update; + last_update = time_now; + return ms; +} + +static ssize_t show_stat_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + int i, j; + int len = 0; + struct freq_entry *freq_entry; + + for (i = 0; i < num_freqs; i++) { + hash_for_each_possible(freq_hash_table, freq_entry, hash, + freq_buckets[i]) { + if (freq_entry->freq == freq_buckets[i]) { + len += scnprintf(buf + len, PAGE_SIZE - len, + "%d ", freq_buckets[i]); + if (len >= PAGE_SIZE) + break; + for (j = 0; j < num_buckets; j++) { + len += scnprintf(buf + len, + PAGE_SIZE - len, + "%llu ", + freq_entry->buckets[j]); + } + len += scnprintf(buf + len, PAGE_SIZE - len, + "\n"); + } + } + } + pr_debug("Current Time: %llu\n", ktime_get_boot_ns()); + return len; +} +KERNEL_ATTR_RO(show_stat); + +static void update_table(u64 time_now) +{ + struct freq_entry *freq_entry; + + pr_debug("Last known bw %d freq %d\n", curr_bw, curr_freq); + hash_for_each_possible(freq_hash_table, freq_entry, hash, curr_freq) { + if (curr_freq == freq_entry->freq) { + freq_entry->buckets[find_bucket(curr_bw)] + += get_time_diff(time_now); + break; + } + } +} + +static bool freq_exists(int freq) +{ + int i; + + for (i = 0; i < num_freqs; i++) { + if (freq == freq_buckets[i]) + return true; + } + return false; +} + +static int calculate_total_bw(int bw, int index) +{ + int i; + int total_bw = 0; + + pr_debug("memory_state_time New bw %d for id %d\n", bw, index); + bandwidths[index] = bw; + for (i = 0; i < registered_bw_sources; i++) + total_bw += bandwidths[i]; + return total_bw; +} + +static void freq_update_do_work(struct work_struct *work) +{ + struct queue_container *freq_state_update + = container_of(work, struct queue_container, + update_state); + if (freq_state_update) { + mutex_lock(&mem_lock); + update_table(freq_state_update->time_now); + curr_freq = freq_state_update->value; + mutex_unlock(&mem_lock); + kfree(freq_state_update); + } +} + +static void bw_update_do_work(struct work_struct *work) +{ + struct queue_container *bw_state_update + = container_of(work, struct queue_container, + update_state); + if (bw_state_update) { + mutex_lock(&mem_lock); + update_table(bw_state_update->time_now); + curr_bw = calculate_total_bw(bw_state_update->value, + bw_state_update->id); + mutex_unlock(&mem_lock); + kfree(bw_state_update); + } +} + +static void memory_state_freq_update(struct memory_state_update_block *ub, + int value) +{ + if (IS_ENABLED(CONFIG_MEMORY_STATE_TIME)) { + if (freq_exists(value) && init_success) { + struct queue_container *freq_container + = kmalloc(sizeof(struct queue_container), + GFP_KERNEL); + if (!freq_container) + return; + INIT_WORK(&freq_container->update_state, + freq_update_do_work); + freq_container->time_now = ktime_get_boot_ns(); + freq_container->value = value; + pr_debug("Scheduling freq update in work queue\n"); + queue_work(memory_wq, &freq_container->update_state); + } else { + pr_debug("Freq does not exist.\n"); + } + } +} + +static void memory_state_bw_update(struct memory_state_update_block *ub, + int value) +{ + if (IS_ENABLED(CONFIG_MEMORY_STATE_TIME)) { + if (init_success) { + struct queue_container *bw_container + = kmalloc(sizeof(struct queue_container), + GFP_KERNEL); + if (!bw_container) + return; + INIT_WORK(&bw_container->update_state, + bw_update_do_work); + bw_container->time_now = ktime_get_boot_ns(); + bw_container->value = value; + bw_container->id = ub->id; + pr_debug("Scheduling bandwidth update in work queue\n"); + queue_work(memory_wq, &bw_container->update_state); + } + } +} + +struct memory_state_update_block *memory_state_register_frequency_source(void) +{ + struct memory_state_update_block *block; + + if (IS_ENABLED(CONFIG_MEMORY_STATE_TIME)) { + pr_debug("Allocating frequency source\n"); + block = kmalloc(sizeof(struct memory_state_update_block), + GFP_KERNEL); + if (!block) + return NULL; + block->update_call = memory_state_freq_update; + return block; + } + pr_err("Config option disabled.\n"); + return NULL; +} +EXPORT_SYMBOL_GPL(memory_state_register_frequency_source); + +struct memory_state_update_block *memory_state_register_bandwidth_source(void) +{ + struct memory_state_update_block *block; + + if (IS_ENABLED(CONFIG_MEMORY_STATE_TIME)) { + pr_debug("Allocating bandwidth source %d\n", + registered_bw_sources); + block = kmalloc(sizeof(struct memory_state_update_block), + GFP_KERNEL); + if (!block) + return NULL; + block->update_call = memory_state_bw_update; + if (registered_bw_sources < num_sources) { + block->id = registered_bw_sources++; + } else { + pr_err("Unable to allocate source; max number reached\n"); + kfree(block); + return NULL; + } + return block; + } + pr_err("Config option disabled.\n"); + return NULL; +} +EXPORT_SYMBOL_GPL(memory_state_register_bandwidth_source); + +/* Buckets are designated by their maximum. + * Returns the buckets decided by the capability of the device. + */ +static int get_bw_buckets(struct device *dev) +{ + int ret, lenb; + struct device_node *node = dev->of_node; + + of_property_read_u32(node, NUM_SOURCES, &num_sources); + if (of_find_property(node, BW_TBL, &lenb)) { + bandwidths = devm_kzalloc(dev, + sizeof(*bandwidths) * num_sources, GFP_KERNEL); + if (!bandwidths) + return -ENOMEM; + lenb /= sizeof(*bw_buckets); + bw_buckets = devm_kzalloc(dev, lenb * sizeof(*bw_buckets), + GFP_KERNEL); + if (!bw_buckets) { + devm_kfree(dev, bandwidths); + return -ENOMEM; + } + ret = of_property_read_u32_array(node, BW_TBL, bw_buckets, + lenb); + if (ret < 0) { + devm_kfree(dev, bandwidths); + devm_kfree(dev, bw_buckets); + pr_err("Unable to read bandwidth table from device tree.\n"); + return ret; + } + } + curr_bw = 0; + num_buckets = lenb; + return 0; +} + +/* Adds struct freq_entry nodes to the hashtable for each compatible frequency. + * Returns the supported number of frequencies. + */ +static int freq_buckets_init(struct device *dev) +{ + struct freq_entry *freq_entry; + int i; + int ret, lenf; + struct device_node *node = dev->of_node; + + if (of_find_property(node, FREQ_TBL, &lenf)) { + lenf /= sizeof(*freq_buckets); + freq_buckets = devm_kzalloc(dev, lenf * sizeof(*freq_buckets), + GFP_KERNEL); + if (!freq_buckets) + return -ENOMEM; + pr_debug("freqs found len %d\n", lenf); + ret = of_property_read_u32_array(node, FREQ_TBL, freq_buckets, + lenf); + if (ret < 0) { + devm_kfree(dev, freq_buckets); + pr_err("Unable to read frequency table from device tree.\n"); + return ret; + } + pr_debug("ret freq %d\n", ret); + } + num_freqs = lenf; + curr_freq = freq_buckets[LOWEST_FREQ]; + + for (i = 0; i < num_freqs; i++) { + freq_entry = devm_kzalloc(dev, sizeof(struct freq_entry), + GFP_KERNEL); + if (!freq_entry) + return -ENOMEM; + freq_entry->buckets = devm_kzalloc(dev, sizeof(u64)*num_buckets, + GFP_KERNEL); + if (!freq_entry->buckets) { + devm_kfree(dev, freq_entry); + return -ENOMEM; + } + pr_debug("memory_state_time Adding freq to ht %d\n", + freq_buckets[i]); + freq_entry->freq = freq_buckets[i]; + hash_add(freq_hash_table, &freq_entry->hash, freq_buckets[i]); + } + return 0; +} + +struct kobject *memory_kobj; +EXPORT_SYMBOL_GPL(memory_kobj); + +static struct attribute *memory_attrs[] = { + &show_stat_attr.attr, + NULL +}; + +static struct attribute_group memory_attr_group = { + .attrs = memory_attrs, +}; + +static int memory_state_time_probe(struct platform_device *pdev) +{ + int error; + + error = get_bw_buckets(&pdev->dev); + if (error) + return error; + error = freq_buckets_init(&pdev->dev); + if (error) + return error; + last_update = ktime_get_boot_ns(); + init_success = true; + + pr_debug("memory_state_time initialized with num_freqs %d\n", + num_freqs); + return 0; +} + +static const struct of_device_id match_table[] = { + { .compatible = "memory-state-time" }, + {} +}; + +static struct platform_driver memory_state_time_driver = { + .probe = memory_state_time_probe, + .driver = { + .name = "memory-state-time", + .of_match_table = match_table, + .owner = THIS_MODULE, + }, +}; + +static int __init memory_state_time_init(void) +{ + int error; + + hash_init(freq_hash_table); + memory_wq = create_singlethread_workqueue("memory_wq"); + if (!memory_wq) { + pr_err("Unable to create workqueue.\n"); + return -EINVAL; + } + /* + * Create sys/kernel directory for memory_state_time. + */ + memory_kobj = kobject_create_and_add(TAG, kernel_kobj); + if (!memory_kobj) { + pr_err("Unable to allocate memory_kobj for sysfs directory.\n"); + error = -ENOMEM; + goto wq; + } + error = sysfs_create_group(memory_kobj, &memory_attr_group); + if (error) { + pr_err("Unable to create sysfs folder.\n"); + goto kobj; + } + + error = platform_driver_register(&memory_state_time_driver); + if (error) { + pr_err("Unable to register memory_state_time platform driver.\n"); + goto group; + } + return 0; + +group: sysfs_remove_group(memory_kobj, &memory_attr_group); +kobj: kobject_put(memory_kobj); +wq: destroy_workqueue(memory_wq); + return error; +} +module_init(memory_state_time_init); |