1 files changed, 242 insertions, 0 deletions

diff --git a/net/mac80211/rc80211_pid.h b/net/mac80211/rc80211_pid.h
new file mode 100644
index 000000000000..5d0056c1513b
--- /dev/null
+++ b/net/mac80211/rc80211_pid.h
@@ -0,0 +1,242 @@
+/*
+ * Copyright 2007, Mattias Nissler <mattias.nissler@gmx.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.
+ */
+
+#ifndef RC80211_PID_H
+#define RC80211_PID_H
+
+/* Sampling period for measuring percentage of failed frames. */
+#define RC_PID_INTERVAL (HZ / 8)
+
+/* Exponential averaging smoothness (used for I part of PID controller) */
+#define RC_PID_SMOOTHING_SHIFT 3
+#define RC_PID_SMOOTHING (1 << RC_PID_SMOOTHING_SHIFT)
+
+/* Sharpening factor (used for D part of PID controller) */
+#define RC_PID_SHARPENING_FACTOR 0
+#define RC_PID_SHARPENING_DURATION 0
+
+/* Fixed point arithmetic shifting amount. */
+#define RC_PID_ARITH_SHIFT 8
+
+/* Fixed point arithmetic factor. */
+#define RC_PID_ARITH_FACTOR (1 << RC_PID_ARITH_SHIFT)
+
+/* Proportional PID component coefficient. */
+#define RC_PID_COEFF_P 15
+/* Integral PID component coefficient. */
+#define RC_PID_COEFF_I 9
+/* Derivative PID component coefficient. */
+#define RC_PID_COEFF_D 15
+
+/* Target failed frames rate for the PID controller. NB: This effectively gives
+ * maximum failed frames percentage we're willing to accept. If the wireless
+ * link quality is good, the controller will fail to adjust failed frames
+ * percentage to the target. This is intentional.
+ */
+#define RC_PID_TARGET_PF (11 << RC_PID_ARITH_SHIFT)
+
+/* Rate behaviour normalization quantity over time. */
+#define RC_PID_NORM_OFFSET 3
+
+/* Push high rates right after loading. */
+#define RC_PID_FAST_START 0
+
+/* Arithmetic right shift for positive and negative values for ISO C. */
+#define RC_PID_DO_ARITH_RIGHT_SHIFT(x, y) \
+        (x) < 0 ? -((-(x)) >> (y)) : (x) >> (y)
+
+enum rc_pid_event_type {
+        RC_PID_EVENT_TYPE_TX_STATUS,
+        RC_PID_EVENT_TYPE_RATE_CHANGE,
+        RC_PID_EVENT_TYPE_TX_RATE,
+        RC_PID_EVENT_TYPE_PF_SAMPLE,
+};
+
+union rc_pid_event_data {
+        /* RC_PID_EVENT_TX_STATUS */
+        struct {
+                struct ieee80211_tx_status tx_status;
+        };
+        /* RC_PID_EVENT_TYPE_RATE_CHANGE */
+        /* RC_PID_EVENT_TYPE_TX_RATE */
+        struct {
+                int index;
+                int rate;
+        };
+        /* RC_PID_EVENT_TYPE_PF_SAMPLE */
+        struct {
+                s32 pf_sample;
+                s32 prop_err;
+                s32 int_err;
+                s32 der_err;
+        };
+};
+
+struct rc_pid_event {
+        /* The time when the event occured */
+        unsigned long timestamp;
+
+        /* Event ID number */
+        unsigned int id;
+
+        /* Type of event */
+        enum rc_pid_event_type type;
+
+        /* type specific data */
+        union rc_pid_event_data data;
+};
+
+/* Size of the event ring buffer. */
+#define RC_PID_EVENT_RING_SIZE 32
+
+struct rc_pid_event_buffer {
+        /* Counter that generates event IDs */
+        unsigned int ev_count;
+
+        /* Ring buffer of events */
+        struct rc_pid_event ring[RC_PID_EVENT_RING_SIZE];
+
+        /* Index to the entry in events_buf to be reused */
+        unsigned int next_entry;
+
+        /* Lock that guards against concurrent access to this buffer struct */
+        spinlock_t lock;
+
+        /* Wait queue for poll/select and blocking I/O */
+        wait_queue_head_t waitqueue;
+};
+
+struct rc_pid_events_file_info {
+        /* The event buffer we read */
+        struct rc_pid_event_buffer *events;
+
+        /* The entry we have should read next */
+        unsigned int next_entry;
+};
+
+void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf,
+                                             struct ieee80211_tx_status *stat);
+
+void rate_control_pid_event_rate_change(struct rc_pid_event_buffer *buf,
+                                               int index, int rate);
+
+void rate_control_pid_event_tx_rate(struct rc_pid_event_buffer *buf,
+                                           int index, int rate);
+
+void rate_control_pid_event_pf_sample(struct rc_pid_event_buffer *buf,
+                                             s32 pf_sample, s32 prop_err,
+                                             s32 int_err, s32 der_err);
+
+void rate_control_pid_add_sta_debugfs(void *priv, void *priv_sta,
+                                             struct dentry *dir);
+
+void rate_control_pid_remove_sta_debugfs(void *priv, void *priv_sta);
+
+struct rc_pid_sta_info {
+        unsigned long last_change;
+        unsigned long last_sample;
+
+        u32 tx_num_failed;
+        u32 tx_num_xmit;
+
+        /* Average failed frames percentage error (i.e. actual vs. target
+         * percentage), scaled by RC_PID_SMOOTHING. This value is computed
+         * using using an exponential weighted average technique:
+         *
+         *           (RC_PID_SMOOTHING - 1) * err_avg_old + err
+         * err_avg = ------------------------------------------
+         *                       RC_PID_SMOOTHING
+         *
+         * where err_avg is the new approximation, err_avg_old the previous one
+         * and err is the error w.r.t. to the current failed frames percentage
+         * sample. Note that the bigger RC_PID_SMOOTHING the more weight is
+         * given to the previous estimate, resulting in smoother behavior (i.e.
+         * corresponding to a longer integration window).
+         *
+         * For computation, we actually don't use the above formula, but this
+         * one:
+         *
+         * err_avg_scaled = err_avg_old_scaled - err_avg_old + err
+         *
+         * where:
+         *      err_avg_scaled = err * RC_PID_SMOOTHING
+         *      err_avg_old_scaled = err_avg_old * RC_PID_SMOOTHING
+         *
+         * This avoids floating point numbers and the per_failed_old value can
+         * easily be obtained by shifting per_failed_old_scaled right by
+         * RC_PID_SMOOTHING_SHIFT.
+         */
+        s32 err_avg_sc;
+
+        /* Last framed failes percentage sample. */
+        u32 last_pf;
+
+        /* Sharpening needed. */
+        u8 sharp_cnt;
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+        /* Event buffer */
+        struct rc_pid_event_buffer events;
+
+        /* Events debugfs file entry */
+        struct dentry *events_entry;
+#endif
+};
+
+/* Algorithm parameters. We keep them on a per-algorithm approach, so they can
+ * be tuned individually for each interface.
+ */
+struct rc_pid_rateinfo {
+
+        /* Map sorted rates to rates in ieee80211_hw_mode. */
+        int index;
+
+        /* Map rates in ieee80211_hw_mode to sorted rates. */
+        int rev_index;
+
+        /* Did we do any measurement on this rate? */
+        bool valid;
+
+        /* Comparison with the lowest rate. */
+        int diff;
+};
+
+struct rc_pid_info {
+
+        /* The failed frames percentage target. */
+        unsigned int target;
+
+        /* Rate at which failed frames percentage is sampled in 0.001s. */
+        unsigned int sampling_period;
+
+        /* P, I and D coefficients. */
+        int coeff_p;
+        int coeff_i;
+        int coeff_d;
+
+        /* Exponential averaging shift. */
+        unsigned int smoothing_shift;
+
+        /* Sharpening shift and duration. */
+        unsigned int sharpen_shift;
+        unsigned int sharpen_duration;
+
+        /* Normalization offset. */
+        unsigned int norm_offset;
+
+        /* Fast starst parameter. */
+        unsigned int fast_start;
+
+        /* Rates information. */
+        struct rc_pid_rateinfo *rinfo;
+
+        /* Index of the last used rate. */
+        int oldrate;
+};
+
+#endif /* RC80211_PID_H */