Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mirror_ubuntu-bionic-kernel.git] / drivers / net / wireless / rt2x00 / rt2x00dev.c

/*
        Copyright (C) 2004 - 2007 rt2x00 SourceForge Project
        <http://rt2x00.serialmonkey.com>

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; either version 2 of the License, or
        (at your option) any later version.

        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.

        You should have received a copy of the GNU General Public License
        along with this program; if not, write to the
        Free Software Foundation, Inc.,
        59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
        Module: rt2x00lib
        Abstract: rt2x00 generic device routines.
 */

#include <linux/kernel.h>
#include <linux/module.h>

#include "rt2x00.h"
#include "rt2x00lib.h"
#include "rt2x00dump.h"

/*
 * Ring handler.
 */
struct data_ring *rt2x00lib_get_ring(struct rt2x00_dev *rt2x00dev,
                                     const unsigned int queue)
{
        int beacon = test_bit(DRIVER_REQUIRE_BEACON_RING, &rt2x00dev->flags);

        /*
         * Check if we are requesting a reqular TX ring,
         * or if we are requesting a Beacon or Atim ring.
         * For Atim rings, we should check if it is supported.
         */
        if (queue < rt2x00dev->hw->queues && rt2x00dev->tx)
                return &rt2x00dev->tx[queue];

        if (!rt2x00dev->bcn || !beacon)
                return NULL;

        if (queue == IEEE80211_TX_QUEUE_BEACON)
                return &rt2x00dev->bcn[0];
        else if (queue == IEEE80211_TX_QUEUE_AFTER_BEACON)
                return &rt2x00dev->bcn[1];

        return NULL;
}
EXPORT_SYMBOL_GPL(rt2x00lib_get_ring);

/*
 * Link tuning handlers
 */
void rt2x00lib_reset_link_tuner(struct rt2x00_dev *rt2x00dev)
{
        if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        /*
         * Reset link information.
         * Both the currently active vgc level as well as
         * the link tuner counter should be reset. Resetting
         * the counter is important for devices where the
         * device should only perform link tuning during the
         * first minute after being enabled.
         */
        rt2x00dev->link.count = 0;
        rt2x00dev->link.vgc_level = 0;

        /*
         * Reset the link tuner.
         */
        rt2x00dev->ops->lib->reset_tuner(rt2x00dev);
}

static void rt2x00lib_start_link_tuner(struct rt2x00_dev *rt2x00dev)
{
        /*
         * Clear all (possibly) pre-existing quality statistics.
         */
        memset(&rt2x00dev->link.qual, 0, sizeof(rt2x00dev->link.qual));

        /*
         * The RX and TX percentage should start at 50%
         * this will assure we will get at least get some
         * decent value when the link tuner starts.
         * The value will be dropped and overwritten with
         * the correct (measured )value anyway during the
         * first run of the link tuner.
         */
        rt2x00dev->link.qual.rx_percentage = 50;
        rt2x00dev->link.qual.tx_percentage = 50;

        rt2x00lib_reset_link_tuner(rt2x00dev);

        queue_delayed_work(rt2x00dev->hw->workqueue,
                           &rt2x00dev->link.work, LINK_TUNE_INTERVAL);
}

static void rt2x00lib_stop_link_tuner(struct rt2x00_dev *rt2x00dev)
{
        cancel_delayed_work_sync(&rt2x00dev->link.work);
}

/*
 * Ring initialization
 */
static void rt2x00lib_init_rxrings(struct rt2x00_dev *rt2x00dev)
{
        struct data_ring *ring = rt2x00dev->rx;
        unsigned int i;

        if (!rt2x00dev->ops->lib->init_rxentry)
                return;

        if (ring->data_addr)
                memset(ring->data_addr, 0, rt2x00_get_ring_size(ring));

        for (i = 0; i < ring->stats.limit; i++)
                rt2x00dev->ops->lib->init_rxentry(rt2x00dev, &ring->entry[i]);

        rt2x00_ring_index_clear(ring);
}

static void rt2x00lib_init_txrings(struct rt2x00_dev *rt2x00dev)
{
        struct data_ring *ring;
        unsigned int i;

        if (!rt2x00dev->ops->lib->init_txentry)
                return;

        txringall_for_each(rt2x00dev, ring) {
                if (ring->data_addr)
                        memset(ring->data_addr, 0, rt2x00_get_ring_size(ring));

                for (i = 0; i < ring->stats.limit; i++)
                        rt2x00dev->ops->lib->init_txentry(rt2x00dev,
                                                          &ring->entry[i]);

                rt2x00_ring_index_clear(ring);
        }
}

/*
 * Radio control handlers.
 */
int rt2x00lib_enable_radio(struct rt2x00_dev *rt2x00dev)
{
        int status;

        /*
         * Don't enable the radio twice.
         * And check if the hardware button has been disabled.
         */
        if (test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags) ||
            test_bit(DEVICE_DISABLED_RADIO_HW, &rt2x00dev->flags))
                return 0;

        /*
         * Initialize all data rings.
         */
        rt2x00lib_init_rxrings(rt2x00dev);
        rt2x00lib_init_txrings(rt2x00dev);

        /*
         * Enable radio.
         */
        status = rt2x00dev->ops->lib->set_device_state(rt2x00dev,
                                                       STATE_RADIO_ON);
        if (status)
                return status;

        __set_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags);

        /*
         * Enable RX.
         */
        rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_ON);

        /*
         * Start the TX queues.
         */
        ieee80211_start_queues(rt2x00dev->hw);

        return 0;
}

void rt2x00lib_disable_radio(struct rt2x00_dev *rt2x00dev)
{
        if (!__test_and_clear_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        /*
         * Stop all scheduled work.
         */
        if (work_pending(&rt2x00dev->beacon_work))
                cancel_work_sync(&rt2x00dev->beacon_work);
        if (work_pending(&rt2x00dev->filter_work))
                cancel_work_sync(&rt2x00dev->filter_work);
        if (work_pending(&rt2x00dev->config_work))
                cancel_work_sync(&rt2x00dev->config_work);

        /*
         * Stop the TX queues.
         */
        ieee80211_stop_queues(rt2x00dev->hw);

        /*
         * Disable RX.
         */
        rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_OFF);

        /*
         * Disable radio.
         */
        rt2x00dev->ops->lib->set_device_state(rt2x00dev, STATE_RADIO_OFF);
}

void rt2x00lib_toggle_rx(struct rt2x00_dev *rt2x00dev, enum dev_state state)
{
        /*
         * When we are disabling the RX, we should also stop the link tuner.
         */
        if (state == STATE_RADIO_RX_OFF)
                rt2x00lib_stop_link_tuner(rt2x00dev);

        rt2x00dev->ops->lib->set_device_state(rt2x00dev, state);

        /*
         * When we are enabling the RX, we should also start the link tuner.
         */
        if (state == STATE_RADIO_RX_ON &&
            is_interface_present(&rt2x00dev->interface))
                rt2x00lib_start_link_tuner(rt2x00dev);
}

static void rt2x00lib_evaluate_antenna_sample(struct rt2x00_dev *rt2x00dev)
{
        enum antenna rx = rt2x00dev->link.ant.active.rx;
        enum antenna tx = rt2x00dev->link.ant.active.tx;
        int sample_a =
            rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_A);
        int sample_b =
            rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_B);

        /*
         * We are done sampling. Now we should evaluate the results.
         */
        rt2x00dev->link.ant.flags &= ~ANTENNA_MODE_SAMPLE;

        /*
         * During the last period we have sampled the RSSI
         * from both antenna's. It now is time to determine
         * which antenna demonstrated the best performance.
         * When we are already on the antenna with the best
         * performance, then there really is nothing for us
         * left to do.
         */
        if (sample_a == sample_b)
                return;

        if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY)
                rx = (sample_a > sample_b) ? ANTENNA_A : ANTENNA_B;

        if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)
                tx = (sample_a > sample_b) ? ANTENNA_A : ANTENNA_B;

        rt2x00lib_config_antenna(rt2x00dev, rx, tx);
}

static void rt2x00lib_evaluate_antenna_eval(struct rt2x00_dev *rt2x00dev)
{
        enum antenna rx = rt2x00dev->link.ant.active.rx;
        enum antenna tx = rt2x00dev->link.ant.active.tx;
        int rssi_curr = rt2x00_get_link_ant_rssi(&rt2x00dev->link);
        int rssi_old = rt2x00_update_ant_rssi(&rt2x00dev->link, rssi_curr);

        /*
         * Legacy driver indicates that we should swap antenna's
         * when the difference in RSSI is greater that 5. This
         * also should be done when the RSSI was actually better
         * then the previous sample.
         * When the difference exceeds the threshold we should
         * sample the rssi from the other antenna to make a valid
         * comparison between the 2 antennas.
         */
        if (abs(rssi_curr - rssi_old) < 5)
                return;

        rt2x00dev->link.ant.flags |= ANTENNA_MODE_SAMPLE;

        if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY)
                rx = (rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;

        if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)
                tx = (tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;

        rt2x00lib_config_antenna(rt2x00dev, rx, tx);
}

static void rt2x00lib_evaluate_antenna(struct rt2x00_dev *rt2x00dev)
{
        /*
         * Determine if software diversity is enabled for
         * either the TX or RX antenna (or both).
         * Always perform this check since within the link
         * tuner interval the configuration might have changed.
         */
        rt2x00dev->link.ant.flags &= ~ANTENNA_RX_DIVERSITY;
        rt2x00dev->link.ant.flags &= ~ANTENNA_TX_DIVERSITY;

        if (rt2x00dev->hw->conf.antenna_sel_rx == 0 &&
            rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY)
                rt2x00dev->link.ant.flags |= ANTENNA_RX_DIVERSITY;
        if (rt2x00dev->hw->conf.antenna_sel_tx == 0 &&
            rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY)
                rt2x00dev->link.ant.flags |= ANTENNA_TX_DIVERSITY;

        if (!(rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY) &&
            !(rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)) {
                rt2x00dev->link.ant.flags = 0;
                return;
        }

        /*
         * If we have only sampled the data over the last period
         * we should now harvest the data. Otherwise just evaluate
         * the data. The latter should only be performed once
         * every 2 seconds.
         */
        if (rt2x00dev->link.ant.flags & ANTENNA_MODE_SAMPLE)
                rt2x00lib_evaluate_antenna_sample(rt2x00dev);
        else if (rt2x00dev->link.count & 1)
                rt2x00lib_evaluate_antenna_eval(rt2x00dev);
}

static void rt2x00lib_update_link_stats(struct link *link, int rssi)
{
        int avg_rssi = rssi;

        /*
         * Update global RSSI
         */
        if (link->qual.avg_rssi)
                avg_rssi = MOVING_AVERAGE(link->qual.avg_rssi, rssi, 8);
        link->qual.avg_rssi = avg_rssi;

        /*
         * Update antenna RSSI
         */
        if (link->ant.rssi_ant)
                rssi = MOVING_AVERAGE(link->ant.rssi_ant, rssi, 8);
        link->ant.rssi_ant = rssi;
}

static void rt2x00lib_precalculate_link_signal(struct link_qual *qual)
{
        if (qual->rx_failed || qual->rx_success)
                qual->rx_percentage =
                    (qual->rx_success * 100) /
                    (qual->rx_failed + qual->rx_success);
        else
                qual->rx_percentage = 50;

        if (qual->tx_failed || qual->tx_success)
                qual->tx_percentage =
                    (qual->tx_success * 100) /
                    (qual->tx_failed + qual->tx_success);
        else
                qual->tx_percentage = 50;

        qual->rx_success = 0;
        qual->rx_failed = 0;
        qual->tx_success = 0;
        qual->tx_failed = 0;
}

static int rt2x00lib_calculate_link_signal(struct rt2x00_dev *rt2x00dev,
                                           int rssi)
{
        int rssi_percentage = 0;
        int signal;

        /*
         * We need a positive value for the RSSI.
         */
        if (rssi < 0)
                rssi += rt2x00dev->rssi_offset;

        /*
         * Calculate the different percentages,
         * which will be used for the signal.
         */
        if (rt2x00dev->rssi_offset)
                rssi_percentage = (rssi * 100) / rt2x00dev->rssi_offset;

        /*
         * Add the individual percentages and use the WEIGHT
         * defines to calculate the current link signal.
         */
        signal = ((WEIGHT_RSSI * rssi_percentage) +
                  (WEIGHT_TX * rt2x00dev->link.qual.tx_percentage) +
                  (WEIGHT_RX * rt2x00dev->link.qual.rx_percentage)) / 100;

        return (signal > 100) ? 100 : signal;
}

static void rt2x00lib_link_tuner(struct work_struct *work)
{
        struct rt2x00_dev *rt2x00dev =
            container_of(work, struct rt2x00_dev, link.work.work);

        /*
         * When the radio is shutting down we should
         * immediately cease all link tuning.
         */
        if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        /*
         * Update statistics.
         */
        rt2x00dev->ops->lib->link_stats(rt2x00dev, &rt2x00dev->link.qual);
        rt2x00dev->low_level_stats.dot11FCSErrorCount +=
            rt2x00dev->link.qual.rx_failed;

        /*
         * Only perform the link tuning when Link tuning
         * has been enabled (This could have been disabled from the EEPROM).
         */
        if (!test_bit(CONFIG_DISABLE_LINK_TUNING, &rt2x00dev->flags))
                rt2x00dev->ops->lib->link_tuner(rt2x00dev);

        /*
         * Precalculate a portion of the link signal which is
         * in based on the tx/rx success/failure counters.
         */
        rt2x00lib_precalculate_link_signal(&rt2x00dev->link.qual);

        /*
         * Evaluate antenna setup, make this the last step since this could
         * possibly reset some statistics.
         */
        rt2x00lib_evaluate_antenna(rt2x00dev);

        /*
         * Increase tuner counter, and reschedule the next link tuner run.
         */
        rt2x00dev->link.count++;
        queue_delayed_work(rt2x00dev->hw->workqueue, &rt2x00dev->link.work,
                           LINK_TUNE_INTERVAL);
}

static void rt2x00lib_packetfilter_scheduled(struct work_struct *work)
{
        struct rt2x00_dev *rt2x00dev =
            container_of(work, struct rt2x00_dev, filter_work);
        unsigned int filter = rt2x00dev->packet_filter;

        /*
         * Since we had stored the filter inside interface.filter,
         * we should now clear that field. Otherwise the driver will
         * assume nothing has changed (*total_flags will be compared
         * to interface.filter to determine if any action is required).
         */
        rt2x00dev->packet_filter = 0;

        rt2x00dev->ops->hw->configure_filter(rt2x00dev->hw,
                                             filter, &filter, 0, NULL);
}

static void rt2x00lib_configuration_scheduled(struct work_struct *work)
{
        struct rt2x00_dev *rt2x00dev =
            container_of(work, struct rt2x00_dev, config_work);
        struct ieee80211_bss_conf bss_conf;

        bss_conf.use_short_preamble =
                test_bit(CONFIG_SHORT_PREAMBLE, &rt2x00dev->flags);

        /*
         * FIXME: shouldn't invoke it this way because all other contents
         *        of bss_conf is invalid.
         */
        rt2x00mac_bss_info_changed(rt2x00dev->hw, rt2x00dev->interface.id,
                                   &bss_conf, BSS_CHANGED_ERP_PREAMBLE);
}

/*
 * Interrupt context handlers.
 */
static void rt2x00lib_beacondone_scheduled(struct work_struct *work)
{
        struct rt2x00_dev *rt2x00dev =
            container_of(work, struct rt2x00_dev, beacon_work);
        struct data_ring *ring =
            rt2x00lib_get_ring(rt2x00dev, IEEE80211_TX_QUEUE_BEACON);
        struct data_entry *entry = rt2x00_get_data_entry(ring);
        struct sk_buff *skb;

        skb = ieee80211_beacon_get(rt2x00dev->hw,
                                   rt2x00dev->interface.id,
                                   &entry->tx_status.control);
        if (!skb)
                return;

        rt2x00dev->ops->hw->beacon_update(rt2x00dev->hw, skb,
                                          &entry->tx_status.control);

        dev_kfree_skb(skb);
}

void rt2x00lib_beacondone(struct rt2x00_dev *rt2x00dev)
{
        if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        queue_work(rt2x00dev->hw->workqueue, &rt2x00dev->beacon_work);
}
EXPORT_SYMBOL_GPL(rt2x00lib_beacondone);

void rt2x00lib_txdone(struct data_entry *entry,
                      const int status, const int retry)
{
        struct rt2x00_dev *rt2x00dev = entry->ring->rt2x00dev;
        struct ieee80211_tx_status *tx_status = &entry->tx_status;
        struct ieee80211_low_level_stats *stats = &rt2x00dev->low_level_stats;
        int success = !!(status == TX_SUCCESS || status == TX_SUCCESS_RETRY);
        int fail = !!(status == TX_FAIL_RETRY || status == TX_FAIL_INVALID ||
                      status == TX_FAIL_OTHER);

        /*
         * Update TX statistics.
         */
        tx_status->flags = 0;
        tx_status->ack_signal = 0;
        tx_status->excessive_retries = (status == TX_FAIL_RETRY);
        tx_status->retry_count = retry;
        rt2x00dev->link.qual.tx_success += success;
        rt2x00dev->link.qual.tx_failed += retry + fail;

        if (!(tx_status->control.flags & IEEE80211_TXCTL_NO_ACK)) {
                if (success)
                        tx_status->flags |= IEEE80211_TX_STATUS_ACK;
                else
                        stats->dot11ACKFailureCount++;
        }

        tx_status->queue_length = entry->ring->stats.limit;
        tx_status->queue_number = tx_status->control.queue;

        if (tx_status->control.flags & IEEE80211_TXCTL_USE_RTS_CTS) {
                if (success)
                        stats->dot11RTSSuccessCount++;
                else
                        stats->dot11RTSFailureCount++;
        }

        /*
         * Send the tx_status to mac80211 & debugfs.
         * mac80211 will clean up the skb structure.
         */
        get_skb_desc(entry->skb)->frame_type = DUMP_FRAME_TXDONE;
        rt2x00debug_dump_frame(rt2x00dev, entry->skb);
        ieee80211_tx_status_irqsafe(rt2x00dev->hw, entry->skb, tx_status);
        entry->skb = NULL;
}
EXPORT_SYMBOL_GPL(rt2x00lib_txdone);

void rt2x00lib_rxdone(struct data_entry *entry, struct sk_buff *skb,
                      struct rxdata_entry_desc *desc)
{
        struct rt2x00_dev *rt2x00dev = entry->ring->rt2x00dev;
        struct ieee80211_rx_status *rx_status = &rt2x00dev->rx_status;
        struct ieee80211_hw_mode *mode;
        struct ieee80211_rate *rate;
        struct ieee80211_hdr *hdr;
        unsigned int i;
        int val = 0;
        u16 fc;

        /*
         * Update RX statistics.
         */
        mode = &rt2x00dev->hwmodes[rt2x00dev->curr_hwmode];
        for (i = 0; i < mode->num_rates; i++) {
                rate = &mode->rates[i];

                /*
                 * When frame was received with an OFDM bitrate,
                 * the signal is the PLCP value. If it was received with
                 * a CCK bitrate the signal is the rate in 0.5kbit/s.
                 */
                if (!desc->ofdm)
                        val = DEVICE_GET_RATE_FIELD(rate->val, RATE);
                else
                        val = DEVICE_GET_RATE_FIELD(rate->val, PLCP);

                if (val == desc->signal) {
                        val = rate->val;
                        break;
                }
        }

        /*
         * Only update link status if this is a beacon frame carrying our bssid.
         */
        hdr = (struct ieee80211_hdr*)skb->data;
        fc = le16_to_cpu(hdr->frame_control);
        if (is_beacon(fc) && desc->my_bss)
                rt2x00lib_update_link_stats(&rt2x00dev->link, desc->rssi);

        rt2x00dev->link.qual.rx_success++;

        rx_status->rate = val;
        rx_status->signal =
            rt2x00lib_calculate_link_signal(rt2x00dev, desc->rssi);
        rx_status->ssi = desc->rssi;
        rx_status->flag = desc->flags;
        rx_status->antenna = rt2x00dev->link.ant.active.rx;

        /*
         * Send frame to mac80211 & debugfs
         */
        get_skb_desc(skb)->frame_type = DUMP_FRAME_RXDONE;
        rt2x00debug_dump_frame(rt2x00dev, skb);
        ieee80211_rx_irqsafe(rt2x00dev->hw, skb, rx_status);
}
EXPORT_SYMBOL_GPL(rt2x00lib_rxdone);

/*
 * TX descriptor initializer
 */
void rt2x00lib_write_tx_desc(struct rt2x00_dev *rt2x00dev,
                             struct sk_buff *skb,
                             struct ieee80211_tx_control *control)
{
        struct txdata_entry_desc desc;
        struct skb_desc *skbdesc = get_skb_desc(skb);
        struct ieee80211_hdr *ieee80211hdr = skbdesc->data;
        int tx_rate;
        int bitrate;
        int length;
        int duration;
        int residual;
        u16 frame_control;
        u16 seq_ctrl;

        memset(&desc, 0, sizeof(desc));

        desc.cw_min = skbdesc->ring->tx_params.cw_min;
        desc.cw_max = skbdesc->ring->tx_params.cw_max;
        desc.aifs = skbdesc->ring->tx_params.aifs;

        /*
         * Identify queue
         */
        if (control->queue < rt2x00dev->hw->queues)
                desc.queue = control->queue;
        else if (control->queue == IEEE80211_TX_QUEUE_BEACON ||
                 control->queue == IEEE80211_TX_QUEUE_AFTER_BEACON)
                desc.queue = QUEUE_MGMT;
        else
                desc.queue = QUEUE_OTHER;

        /*
         * Read required fields from ieee80211 header.
         */
        frame_control = le16_to_cpu(ieee80211hdr->frame_control);
        seq_ctrl = le16_to_cpu(ieee80211hdr->seq_ctrl);

        tx_rate = control->tx_rate;

        /*
         * Check whether this frame is to be acked
         */
        if (!(control->flags & IEEE80211_TXCTL_NO_ACK))
                __set_bit(ENTRY_TXD_ACK, &desc.flags);

        /*
         * Check if this is a RTS/CTS frame
         */
        if (is_rts_frame(frame_control) || is_cts_frame(frame_control)) {
                __set_bit(ENTRY_TXD_BURST, &desc.flags);
                if (is_rts_frame(frame_control)) {
                        __set_bit(ENTRY_TXD_RTS_FRAME, &desc.flags);
                        __set_bit(ENTRY_TXD_ACK, &desc.flags);
                } else
                        __clear_bit(ENTRY_TXD_ACK, &desc.flags);
                if (control->rts_cts_rate)
                        tx_rate = control->rts_cts_rate;
        }

        /*
         * Check for OFDM
         */
        if (DEVICE_GET_RATE_FIELD(tx_rate, RATEMASK) & DEV_OFDM_RATEMASK)
                __set_bit(ENTRY_TXD_OFDM_RATE, &desc.flags);

        /*
         * Check if more fragments are pending
         */
        if (ieee80211_get_morefrag(ieee80211hdr)) {
                __set_bit(ENTRY_TXD_BURST, &desc.flags);
                __set_bit(ENTRY_TXD_MORE_FRAG, &desc.flags);
        }

        /*
         * Beacons and probe responses require the tsf timestamp
         * to be inserted into the frame.
         */
        if (control->queue == IEEE80211_TX_QUEUE_BEACON ||
            is_probe_resp(frame_control))
                __set_bit(ENTRY_TXD_REQ_TIMESTAMP, &desc.flags);

        /*
         * Determine with what IFS priority this frame should be send.
         * Set ifs to IFS_SIFS when the this is not the first fragment,
         * or this fragment came after RTS/CTS.
         */
        if ((seq_ctrl & IEEE80211_SCTL_FRAG) > 0 ||
            test_bit(ENTRY_TXD_RTS_FRAME, &desc.flags))
                desc.ifs = IFS_SIFS;
        else
                desc.ifs = IFS_BACKOFF;

        /*
         * PLCP setup
         * Length calculation depends on OFDM/CCK rate.
         */
        desc.signal = DEVICE_GET_RATE_FIELD(tx_rate, PLCP);
        desc.service = 0x04;

        length = skbdesc->data_len + FCS_LEN;
        if (test_bit(ENTRY_TXD_OFDM_RATE, &desc.flags)) {
                desc.length_high = (length >> 6) & 0x3f;
                desc.length_low = length & 0x3f;
        } else {
                bitrate = DEVICE_GET_RATE_FIELD(tx_rate, RATE);

                /*
                 * Convert length to microseconds.
                 */
                residual = get_duration_res(length, bitrate);
                duration = get_duration(length, bitrate);

                if (residual != 0) {
                        duration++;

                        /*
                         * Check if we need to set the Length Extension
                         */
                        if (bitrate == 110 && residual <= 30)
                                desc.service |= 0x80;
                }

                desc.length_high = (duration >> 8) & 0xff;
                desc.length_low = duration & 0xff;

                /*
                 * When preamble is enabled we should set the
                 * preamble bit for the signal.
                 */
                if (DEVICE_GET_RATE_FIELD(tx_rate, PREAMBLE))
                        desc.signal |= 0x08;
        }

        rt2x00dev->ops->lib->write_tx_desc(rt2x00dev, skb, &desc, control);

        /*
         * Update ring entry.
         */
        skbdesc->entry->skb = skb;
        memcpy(&skbdesc->entry->tx_status.control, control, sizeof(*control));

        /*
         * The frame has been completely initialized and ready
         * for sending to the device. The caller will push the
         * frame to the device, but we are going to push the
         * frame to debugfs here.
         */
        skbdesc->frame_type = DUMP_FRAME_TX;
        rt2x00debug_dump_frame(rt2x00dev, skb);
}
EXPORT_SYMBOL_GPL(rt2x00lib_write_tx_desc);

/*
 * Driver initialization handlers.
 */
static void rt2x00lib_channel(struct ieee80211_channel *entry,
                              const int channel, const int tx_power,
                              const int value)
{
        entry->chan = channel;
        if (channel <= 14)
                entry->freq = 2407 + (5 * channel);
        else
                entry->freq = 5000 + (5 * channel);
        entry->val = value;
        entry->flag =
            IEEE80211_CHAN_W_IBSS |
            IEEE80211_CHAN_W_ACTIVE_SCAN |
            IEEE80211_CHAN_W_SCAN;
        entry->power_level = tx_power;
        entry->antenna_max = 0xff;
}

static void rt2x00lib_rate(struct ieee80211_rate *entry,
                           const int rate, const int mask,
                           const int plcp, const int flags)
{
        entry->rate = rate;
        entry->val =
            DEVICE_SET_RATE_FIELD(rate, RATE) |
            DEVICE_SET_RATE_FIELD(mask, RATEMASK) |
            DEVICE_SET_RATE_FIELD(plcp, PLCP);
        entry->flags = flags;
        entry->val2 = entry->val;
        if (entry->flags & IEEE80211_RATE_PREAMBLE2)
                entry->val2 |= DEVICE_SET_RATE_FIELD(1, PREAMBLE);
        entry->min_rssi_ack = 0;
        entry->min_rssi_ack_delta = 0;
}

static int rt2x00lib_probe_hw_modes(struct rt2x00_dev *rt2x00dev,
                                    struct hw_mode_spec *spec)
{
        struct ieee80211_hw *hw = rt2x00dev->hw;
        struct ieee80211_hw_mode *hwmodes;
        struct ieee80211_channel *channels;
        struct ieee80211_rate *rates;
        unsigned int i;
        unsigned char tx_power;

        hwmodes = kzalloc(sizeof(*hwmodes) * spec->num_modes, GFP_KERNEL);
        if (!hwmodes)
                goto exit;

        channels = kzalloc(sizeof(*channels) * spec->num_channels, GFP_KERNEL);
        if (!channels)
                goto exit_free_modes;

        rates = kzalloc(sizeof(*rates) * spec->num_rates, GFP_KERNEL);
        if (!rates)
                goto exit_free_channels;

        /*
         * Initialize Rate list.
         */
        rt2x00lib_rate(&rates[0], 10, DEV_RATEMASK_1MB,
                       0x00, IEEE80211_RATE_CCK);
        rt2x00lib_rate(&rates[1], 20, DEV_RATEMASK_2MB,
                       0x01, IEEE80211_RATE_CCK_2);
        rt2x00lib_rate(&rates[2], 55, DEV_RATEMASK_5_5MB,
                       0x02, IEEE80211_RATE_CCK_2);
        rt2x00lib_rate(&rates[3], 110, DEV_RATEMASK_11MB,
                       0x03, IEEE80211_RATE_CCK_2);

        if (spec->num_rates > 4) {
                rt2x00lib_rate(&rates[4], 60, DEV_RATEMASK_6MB,
                               0x0b, IEEE80211_RATE_OFDM);
                rt2x00lib_rate(&rates[5], 90, DEV_RATEMASK_9MB,
                               0x0f, IEEE80211_RATE_OFDM);
                rt2x00lib_rate(&rates[6], 120, DEV_RATEMASK_12MB,
                               0x0a, IEEE80211_RATE_OFDM);
                rt2x00lib_rate(&rates[7], 180, DEV_RATEMASK_18MB,
                               0x0e, IEEE80211_RATE_OFDM);
                rt2x00lib_rate(&rates[8], 240, DEV_RATEMASK_24MB,
                               0x09, IEEE80211_RATE_OFDM);
                rt2x00lib_rate(&rates[9], 360, DEV_RATEMASK_36MB,
                               0x0d, IEEE80211_RATE_OFDM);
                rt2x00lib_rate(&rates[10], 480, DEV_RATEMASK_48MB,
                               0x08, IEEE80211_RATE_OFDM);
                rt2x00lib_rate(&rates[11], 540, DEV_RATEMASK_54MB,
                               0x0c, IEEE80211_RATE_OFDM);
        }

        /*
         * Initialize Channel list.
         */
        for (i = 0; i < spec->num_channels; i++) {
                if (spec->channels[i].channel <= 14)
                        tx_power = spec->tx_power_bg[i];
                else if (spec->tx_power_a)
                        tx_power = spec->tx_power_a[i];
                else
                        tx_power = spec->tx_power_default;

                rt2x00lib_channel(&channels[i],
                                  spec->channels[i].channel, tx_power, i);
        }

        /*
         * Intitialize 802.11b
         * Rates: CCK.
         * Channels: OFDM.
         */
        if (spec->num_modes > HWMODE_B) {
                hwmodes[HWMODE_B].mode = MODE_IEEE80211B;
                hwmodes[HWMODE_B].num_channels = 14;
                hwmodes[HWMODE_B].num_rates = 4;
                hwmodes[HWMODE_B].channels = channels;
                hwmodes[HWMODE_B].rates = rates;
        }

        /*
         * Intitialize 802.11g
         * Rates: CCK, OFDM.
         * Channels: OFDM.
         */
        if (spec->num_modes > HWMODE_G) {
                hwmodes[HWMODE_G].mode = MODE_IEEE80211G;
                hwmodes[HWMODE_G].num_channels = 14;
                hwmodes[HWMODE_G].num_rates = spec->num_rates;
                hwmodes[HWMODE_G].channels = channels;
                hwmodes[HWMODE_G].rates = rates;
        }

        /*
         * Intitialize 802.11a
         * Rates: OFDM.
         * Channels: OFDM, UNII, HiperLAN2.
         */
        if (spec->num_modes > HWMODE_A) {
                hwmodes[HWMODE_A].mode = MODE_IEEE80211A;
                hwmodes[HWMODE_A].num_channels = spec->num_channels - 14;
                hwmodes[HWMODE_A].num_rates = spec->num_rates - 4;
                hwmodes[HWMODE_A].channels = &channels[14];
                hwmodes[HWMODE_A].rates = &rates[4];
        }

        if (spec->num_modes > HWMODE_G &&
            ieee80211_register_hwmode(hw, &hwmodes[HWMODE_G]))
                goto exit_free_rates;

        if (spec->num_modes > HWMODE_B &&
            ieee80211_register_hwmode(hw, &hwmodes[HWMODE_B]))
                goto exit_free_rates;

        if (spec->num_modes > HWMODE_A &&
            ieee80211_register_hwmode(hw, &hwmodes[HWMODE_A]))
                goto exit_free_rates;

        rt2x00dev->hwmodes = hwmodes;

        return 0;

exit_free_rates:
        kfree(rates);

exit_free_channels:
        kfree(channels);

exit_free_modes:
        kfree(hwmodes);

exit:
        ERROR(rt2x00dev, "Allocation ieee80211 modes failed.\n");
        return -ENOMEM;
}

static void rt2x00lib_remove_hw(struct rt2x00_dev *rt2x00dev)
{
        if (test_bit(DEVICE_REGISTERED_HW, &rt2x00dev->flags))
                ieee80211_unregister_hw(rt2x00dev->hw);

        if (likely(rt2x00dev->hwmodes)) {
                kfree(rt2x00dev->hwmodes->channels);
                kfree(rt2x00dev->hwmodes->rates);
                kfree(rt2x00dev->hwmodes);
                rt2x00dev->hwmodes = NULL;
        }
}

static int rt2x00lib_probe_hw(struct rt2x00_dev *rt2x00dev)
{
        struct hw_mode_spec *spec = &rt2x00dev->spec;
        int status;

        /*
         * Initialize HW modes.
         */
        status = rt2x00lib_probe_hw_modes(rt2x00dev, spec);
        if (status)
                return status;

        /*
         * Register HW.
         */
        status = ieee80211_register_hw(rt2x00dev->hw);
        if (status) {
                rt2x00lib_remove_hw(rt2x00dev);
                return status;
        }

        __set_bit(DEVICE_REGISTERED_HW, &rt2x00dev->flags);

        return 0;
}

/*
 * Initialization/uninitialization handlers.
 */
static int rt2x00lib_alloc_entries(struct data_ring *ring,
                                   const u16 max_entries, const u16 data_size,
                                   const u16 desc_size)
{
        struct data_entry *entry;
        unsigned int i;

        ring->stats.limit = max_entries;
        ring->data_size = data_size;
        ring->desc_size = desc_size;

        /*
         * Allocate all ring entries.
         */
        entry = kzalloc(ring->stats.limit * sizeof(*entry), GFP_KERNEL);
        if (!entry)
                return -ENOMEM;

        for (i = 0; i < ring->stats.limit; i++) {
                entry[i].flags = 0;
                entry[i].ring = ring;
                entry[i].skb = NULL;
                entry[i].entry_idx = i;
        }

        ring->entry = entry;

        return 0;
}

static int rt2x00lib_alloc_ring_entries(struct rt2x00_dev *rt2x00dev)
{
        struct data_ring *ring;

        /*
         * Allocate the RX ring.
         */
        if (rt2x00lib_alloc_entries(rt2x00dev->rx, RX_ENTRIES, DATA_FRAME_SIZE,
                                    rt2x00dev->ops->rxd_size))
                return -ENOMEM;

        /*
         * First allocate the TX rings.
         */
        txring_for_each(rt2x00dev, ring) {
                if (rt2x00lib_alloc_entries(ring, TX_ENTRIES, DATA_FRAME_SIZE,
                                            rt2x00dev->ops->txd_size))
                        return -ENOMEM;
        }

        if (!test_bit(DRIVER_REQUIRE_BEACON_RING, &rt2x00dev->flags))
                return 0;

        /*
         * Allocate the BEACON ring.
         */
        if (rt2x00lib_alloc_entries(&rt2x00dev->bcn[0], BEACON_ENTRIES,
                                    MGMT_FRAME_SIZE, rt2x00dev->ops->txd_size))
                return -ENOMEM;

        /*
         * Allocate the Atim ring.
         */
        if (rt2x00lib_alloc_entries(&rt2x00dev->bcn[1], ATIM_ENTRIES,
                                    DATA_FRAME_SIZE, rt2x00dev->ops->txd_size))
                return -ENOMEM;

        return 0;
}

static void rt2x00lib_free_ring_entries(struct rt2x00_dev *rt2x00dev)
{
        struct data_ring *ring;

        ring_for_each(rt2x00dev, ring) {
                kfree(ring->entry);
                ring->entry = NULL;
        }
}

static void rt2x00lib_uninitialize(struct rt2x00_dev *rt2x00dev)
{
        if (!__test_and_clear_bit(DEVICE_INITIALIZED, &rt2x00dev->flags))
                return;

        /*
         * Unregister extra components.
         */
        rt2x00rfkill_unregister(rt2x00dev);

        /*
         * Allow the HW to uninitialize.
         */
        rt2x00dev->ops->lib->uninitialize(rt2x00dev);

        /*
         * Free allocated ring entries.
         */
        rt2x00lib_free_ring_entries(rt2x00dev);
}

static int rt2x00lib_initialize(struct rt2x00_dev *rt2x00dev)
{
        int status;

        if (test_bit(DEVICE_INITIALIZED, &rt2x00dev->flags))
                return 0;

        /*
         * Allocate all ring entries.
         */
        status = rt2x00lib_alloc_ring_entries(rt2x00dev);
        if (status) {
                ERROR(rt2x00dev, "Ring entries allocation failed.\n");
                return status;
        }

        /*
         * Initialize the device.
         */
        status = rt2x00dev->ops->lib->initialize(rt2x00dev);
        if (status)
                goto exit;

        __set_bit(DEVICE_INITIALIZED, &rt2x00dev->flags);

        /*
         * Register the extra components.
         */
        rt2x00rfkill_register(rt2x00dev);

        return 0;

exit_unitialize:
        rt2x00lib_uninitialize(rt2x00dev);

exit:
        rt2x00lib_free_ring_entries(rt2x00dev);

        return status;
}

int rt2x00lib_start(struct rt2x00_dev *rt2x00dev)
{
        int retval;

        if (test_bit(DEVICE_STARTED, &rt2x00dev->flags))
                return 0;

        /*
         * If this is the first interface which is added,
         * we should load the firmware now.
         */
        if (test_bit(DRIVER_REQUIRE_FIRMWARE, &rt2x00dev->flags)) {
                retval = rt2x00lib_load_firmware(rt2x00dev);
                if (retval)
                        return retval;
        }

        /*
         * Initialize the device.
         */
        retval = rt2x00lib_initialize(rt2x00dev);
        if (retval)
                return retval;

        /*
         * Enable radio.
         */
        retval = rt2x00lib_enable_radio(rt2x00dev);
        if (retval) {
                rt2x00lib_uninitialize(rt2x00dev);
                return retval;
        }

        __set_bit(DEVICE_STARTED, &rt2x00dev->flags);

        return 0;
}

void rt2x00lib_stop(struct rt2x00_dev *rt2x00dev)
{
        if (!test_bit(DEVICE_STARTED, &rt2x00dev->flags))
                return;

        /*
         * Perhaps we can add something smarter here,
         * but for now just disabling the radio should do.
         */
        rt2x00lib_disable_radio(rt2x00dev);

        __clear_bit(DEVICE_STARTED, &rt2x00dev->flags);
}

/*
 * driver allocation handlers.
 */
static int rt2x00lib_alloc_rings(struct rt2x00_dev *rt2x00dev)
{
        struct data_ring *ring;
        unsigned int index;

        /*
         * We need the following rings:
         * RX: 1
         * TX: hw->queues
         * Beacon: 1 (if required)
         * Atim: 1 (if required)
         */
        rt2x00dev->data_rings = 1 + rt2x00dev->hw->queues +
            (2 * test_bit(DRIVER_REQUIRE_BEACON_RING, &rt2x00dev->flags));

        ring = kzalloc(rt2x00dev->data_rings * sizeof(*ring), GFP_KERNEL);
        if (!ring) {
                ERROR(rt2x00dev, "Ring allocation failed.\n");
                return -ENOMEM;
        }

        /*
         * Initialize pointers
         */
        rt2x00dev->rx = ring;
        rt2x00dev->tx = &rt2x00dev->rx[1];
        if (test_bit(DRIVER_REQUIRE_BEACON_RING, &rt2x00dev->flags))
                rt2x00dev->bcn = &rt2x00dev->tx[rt2x00dev->hw->queues];

        /*
         * Initialize ring parameters.
         * RX: queue_idx = 0
         * TX: queue_idx = IEEE80211_TX_QUEUE_DATA0 + index
         * TX: cw_min: 2^5 = 32.
         * TX: cw_max: 2^10 = 1024.
         */
        rt2x00dev->rx->rt2x00dev = rt2x00dev;
        rt2x00dev->rx->queue_idx = 0;

        index = IEEE80211_TX_QUEUE_DATA0;
        txring_for_each(rt2x00dev, ring) {
                ring->rt2x00dev = rt2x00dev;
                ring->queue_idx = index++;
                ring->tx_params.aifs = 2;
                ring->tx_params.cw_min = 5;
                ring->tx_params.cw_max = 10;
        }

        return 0;
}

static void rt2x00lib_free_rings(struct rt2x00_dev *rt2x00dev)
{
        kfree(rt2x00dev->rx);
        rt2x00dev->rx = NULL;
        rt2x00dev->tx = NULL;
        rt2x00dev->bcn = NULL;
}

int rt2x00lib_probe_dev(struct rt2x00_dev *rt2x00dev)
{
        int retval = -ENOMEM;

        /*
         * Let the driver probe the device to detect the capabilities.
         */
        retval = rt2x00dev->ops->lib->probe_hw(rt2x00dev);
        if (retval) {
                ERROR(rt2x00dev, "Failed to allocate device.\n");
                goto exit;
        }

        /*
         * Initialize configuration work.
         */
        INIT_WORK(&rt2x00dev->beacon_work, rt2x00lib_beacondone_scheduled);
        INIT_WORK(&rt2x00dev->filter_work, rt2x00lib_packetfilter_scheduled);
        INIT_WORK(&rt2x00dev->config_work, rt2x00lib_configuration_scheduled);
        INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00lib_link_tuner);

        /*
         * Reset current working type.
         */
        rt2x00dev->interface.type = IEEE80211_IF_TYPE_INVALID;

        /*
         * Allocate ring array.
         */
        retval = rt2x00lib_alloc_rings(rt2x00dev);
        if (retval)
                goto exit;

        /*
         * Initialize ieee80211 structure.
         */
        retval = rt2x00lib_probe_hw(rt2x00dev);
        if (retval) {
                ERROR(rt2x00dev, "Failed to initialize hw.\n");
                goto exit;
        }

        /*
         * Register extra components.
         */
        rt2x00rfkill_allocate(rt2x00dev);
        rt2x00debug_register(rt2x00dev);

        __set_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        return 0;

exit:
        rt2x00lib_remove_dev(rt2x00dev);

        return retval;
}
EXPORT_SYMBOL_GPL(rt2x00lib_probe_dev);

void rt2x00lib_remove_dev(struct rt2x00_dev *rt2x00dev)
{
        __clear_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        /*
         * Disable radio.
         */
        rt2x00lib_disable_radio(rt2x00dev);

        /*
         * Uninitialize device.
         */
        rt2x00lib_uninitialize(rt2x00dev);

        /*
         * Free extra components
         */
        rt2x00debug_deregister(rt2x00dev);
        rt2x00rfkill_free(rt2x00dev);

        /*
         * Free ieee80211_hw memory.
         */
        rt2x00lib_remove_hw(rt2x00dev);

        /*
         * Free firmware image.
         */
        rt2x00lib_free_firmware(rt2x00dev);

        /*
         * Free ring structures.
         */
        rt2x00lib_free_rings(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00lib_remove_dev);

/*
 * Device state handlers
 */
#ifdef CONFIG_PM
int rt2x00lib_suspend(struct rt2x00_dev *rt2x00dev, pm_message_t state)
{
        int retval;

        NOTICE(rt2x00dev, "Going to sleep.\n");
        __clear_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        /*
         * Only continue if mac80211 has open interfaces.
         */
        if (!test_bit(DEVICE_STARTED, &rt2x00dev->flags))
                goto exit;
        __set_bit(DEVICE_STARTED_SUSPEND, &rt2x00dev->flags);

        /*
         * Disable radio.
         */
        rt2x00lib_stop(rt2x00dev);
        rt2x00lib_uninitialize(rt2x00dev);

        /*
         * Suspend/disable extra components.
         */
        rt2x00rfkill_suspend(rt2x00dev);
        rt2x00debug_deregister(rt2x00dev);

exit:
        /*
         * Set device mode to sleep for power management.
         */
        retval = rt2x00dev->ops->lib->set_device_state(rt2x00dev, STATE_SLEEP);
        if (retval)
                return retval;

        return 0;
}
EXPORT_SYMBOL_GPL(rt2x00lib_suspend);

int rt2x00lib_resume(struct rt2x00_dev *rt2x00dev)
{
        struct interface *intf = &rt2x00dev->interface;
        int retval;

        NOTICE(rt2x00dev, "Waking up.\n");

        /*
         * Restore/enable extra components.
         */
        rt2x00debug_register(rt2x00dev);
        rt2x00rfkill_resume(rt2x00dev);

        /*
         * Only continue if mac80211 had open interfaces.
         */
        if (!__test_and_clear_bit(DEVICE_STARTED_SUSPEND, &rt2x00dev->flags))
                return 0;

        /*
         * Reinitialize device and all active interfaces.
         */
        retval = rt2x00lib_start(rt2x00dev);
        if (retval)
                goto exit;

        /*
         * Reconfigure device.
         */
        rt2x00lib_config(rt2x00dev, &rt2x00dev->hw->conf, 1);
        if (!rt2x00dev->hw->conf.radio_enabled)
                rt2x00lib_disable_radio(rt2x00dev);

        rt2x00lib_config_mac_addr(rt2x00dev, intf->mac);
        rt2x00lib_config_bssid(rt2x00dev, intf->bssid);
        rt2x00lib_config_type(rt2x00dev, intf->type);

        /*
         * We are ready again to receive requests from mac80211.
         */
        __set_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        /*
         * It is possible that during that mac80211 has attempted
         * to send frames while we were suspending or resuming.
         * In that case we have disabled the TX queue and should
         * now enable it again
         */
        ieee80211_start_queues(rt2x00dev->hw);

        /*
         * When in Master or Ad-hoc mode,
         * restart Beacon transmitting by faking a beacondone event.
         */
        if (intf->type == IEEE80211_IF_TYPE_AP ||
            intf->type == IEEE80211_IF_TYPE_IBSS)
                rt2x00lib_beacondone(rt2x00dev);

        return 0;

exit:
        rt2x00lib_disable_radio(rt2x00dev);
        rt2x00lib_uninitialize(rt2x00dev);
        rt2x00debug_deregister(rt2x00dev);

        return retval;
}
EXPORT_SYMBOL_GPL(rt2x00lib_resume);
#endif /* CONFIG_PM */

/*
 * rt2x00lib module information.
 */
MODULE_AUTHOR(DRV_PROJECT);
MODULE_VERSION(DRV_VERSION);
MODULE_DESCRIPTION("rt2x00 library");
MODULE_LICENSE("GPL");