M7350/external/compat-wireless/compat/compat-2.6.38.c
2024-09-09 08:57:42 +00:00

51 lines
1.4 KiB
C

/*
* Copyright 2010 Hauke Mehrtens <hauke@hauke-m.de>
*
* 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.
*
* Compatibility file for Linux wireless for kernels 2.6.38.
*/
#include <linux/compat.h>
#include <linux/module.h>
#include <linux/bug.h>
/**
* ewma_init() - Initialize EWMA parameters
* @avg: Average structure
* @factor: Factor to use for the scaled up internal value. The maximum value
* of averages can be ULONG_MAX/(factor*weight).
* @weight: Exponential weight, or decay rate. This defines how fast the
* influence of older values decreases. Has to be bigger than 1.
*
* Initialize the EWMA parameters for a given struct ewma @avg.
*/
void ewma_init(struct ewma *avg, unsigned long factor, unsigned long weight)
{
WARN_ON(weight <= 1 || factor == 0);
avg->internal = 0;
avg->weight = weight;
avg->factor = factor;
}
EXPORT_SYMBOL(ewma_init);
/**
* ewma_add() - Exponentially weighted moving average (EWMA)
* @avg: Average structure
* @val: Current value
*
* Add a sample to the average.
*/
struct ewma *ewma_add(struct ewma *avg, unsigned long val)
{
avg->internal = avg->internal ?
(((avg->internal * (avg->weight - 1)) +
(val * avg->factor)) / avg->weight) :
(val * avg->factor);
return avg;
}
EXPORT_SYMBOL(ewma_add);