/*
 * Copyright (c) 2004-2008 Reyk Floeter <reyk@openbsd.org>
 * Copyright (c) 2006-2008 Nick Kossifidis <mickflemm@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

/********************************************\
Queue Control Unit, DCF Control Unit Functions
\********************************************/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "ath5k.h"
#include "reg.h"
#include "debug.h"
#include <linux/log2.h>

/**
 * DOC: Queue Control Unit (QCU)/DCF Control Unit (DCU) functions
 *
 * Here we setup parameters for the 12 available TX queues. Note that
 * on the various registers we can usually only map the first 10 of them so
 * basically we have 10 queues to play with. Each queue has a matching
 * QCU that controls when the queue will get triggered and multiple QCUs
 * can be mapped to a single DCU that controls the various DFS parameters
 * for the various queues. In our setup we have a 1:1 mapping between QCUs
 * and DCUs allowing us to have different DFS settings for each queue.
 *
 * When a frame goes into a TX queue, QCU decides when it'll trigger a
 * transmission based on various criteria (such as how many data we have inside
 * it's buffer or -if it's a beacon queue- if it's time to fire up the queue
 * based on TSF etc), DCU adds backoff, IFSes etc and then a scheduler
 * (arbitrator) decides the priority of each QCU based on it's configuration
 * (e.g. beacons are always transmitted when they leave DCU bypassing all other
 * frames from other queues waiting to be transmitted). After a frame leaves
 * the DCU it goes to PCU for further processing and then to PHY for
 * the actual transmission.
 */


/******************\
* Helper functions *
\******************/

/**
 * ath5k_hw_num_tx_pending() - Get number of pending frames for a  given queue
 * @ah: The &struct ath5k_hw
 * @queue: One of enum ath5k_tx_queue_id
 */
u32
ath5k_hw_num_tx_pending(struct ath5k_hw *ah, unsigned int queue)
{
        u32 pending;
        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

        /* Return if queue is declared inactive */
        if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
                return false;

        /* XXX: How about AR5K_CFG_TXCNT ? */
        if (ah->ah_version == AR5K_AR5210)
                return false;

        pending = ath5k_hw_reg_read(ah, AR5K_QUEUE_STATUS(queue));
        pending &= AR5K_QCU_STS_FRMPENDCNT;

        /* It's possible to have no frames pending even if TXE
         * is set. To indicate that q has not stopped return
         * true */
        if (!pending && AR5K_REG_READ_Q(ah, AR5K_QCU_TXE, queue))
                return true;

        return pending;
}

/**
 * ath5k_hw_release_tx_queue() - Set a transmit queue inactive
 * @ah: The &struct ath5k_hw
 * @queue: One of enum ath5k_tx_queue_id
 */
void
ath5k_hw_release_tx_queue(struct ath5k_hw *ah, unsigned int queue)
{
        if (WARN_ON(queue >= ah->ah_capabilities.cap_queues.q_tx_num))
                return;

        /* This queue will be skipped in further operations */
        ah->ah_txq[queue].tqi_type = AR5K_TX_QUEUE_INACTIVE;
        /*For SIMR setup*/
        AR5K_Q_DISABLE_BITS(ah->ah_txq_status, queue);
}

/**
 * ath5k_cw_validate() - Make sure the given cw is valid
 * @cw_req: The contention window value to check
 *
 * Make sure cw is a power of 2 minus 1 and smaller than 1024
 */
static u16
ath5k_cw_validate(u16 cw_req)
{
        cw_req = min(cw_req, (u16)1023);

        /* Check if cw_req + 1 a power of 2 */
        if (is_power_of_2(cw_req + 1))
                return cw_req;

        /* Check if cw_req is a power of 2 */
        if (is_power_of_2(cw_req))
                return cw_req - 1;

        /* If none of the above is correct
         * find the closest power of 2 */
        cw_req = (u16) roundup_pow_of_two(cw_req) - 1;

        return cw_req;
}

/**
 * ath5k_hw_get_tx_queueprops() - Get properties for a transmit queue
 * @ah: The &struct ath5k_hw
 * @queue: One of enum ath5k_tx_queue_id
 * @queue_info: The &struct ath5k_txq_info to fill
 */
int
ath5k_hw_get_tx_queueprops(struct ath5k_hw *ah, int queue,
                struct ath5k_txq_info *queue_info)
{
        memcpy(queue_info, &ah->ah_txq[queue], sizeof(struct ath5k_txq_info));
        return 0;
}

/**
 * ath5k_hw_set_tx_queueprops() - Set properties for a transmit queue
 * @ah: The &struct ath5k_hw
 * @queue: One of enum ath5k_tx_queue_id
 * @qinfo: The &struct ath5k_txq_info to use
 *
 * Returns 0 on success or -EIO if queue is inactive
 */
int
ath5k_hw_set_tx_queueprops(struct ath5k_hw *ah, int queue,
                                const struct ath5k_txq_info *qinfo)
{
        struct ath5k_txq_info *qi;

        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

        qi = &ah->ah_txq[queue];

        if (qi->tqi_type == AR5K_TX_QUEUE_INACTIVE)
                return -EIO;

        /* copy and validate values */
        qi->tqi_type = qinfo->tqi_type;
        qi->tqi_subtype = qinfo->tqi_subtype;
        qi->tqi_flags = qinfo->tqi_flags;
        /*
         * According to the docs: Although the AIFS field is 8 bit wide,
         * the maximum supported value is 0xFC. Setting it higher than that
         * will cause the DCU to hang.
         */
        qi->tqi_aifs = min(qinfo->tqi_aifs, (u8)0xFC);
        qi->tqi_cw_min = ath5k_cw_validate(qinfo->tqi_cw_min);
        qi->tqi_cw_max = ath5k_cw_validate(qinfo->tqi_cw_max);
        qi->tqi_cbr_period = qinfo->tqi_cbr_period;
        qi->tqi_cbr_overflow_limit = qinfo->tqi_cbr_overflow_limit;
        qi->tqi_burst_time = qinfo->tqi_burst_time;
        qi->tqi_ready_time = qinfo->tqi_ready_time;

        /*XXX: Is this supported on 5210 ?*/
        /*XXX: Is this correct for AR5K_WME_AC_VI,VO ???*/
        if ((qinfo->tqi_type == AR5K_TX_QUEUE_DATA &&
                ((qinfo->tqi_subtype == AR5K_WME_AC_VI) ||
                 (qinfo->tqi_subtype == AR5K_WME_AC_VO))) ||
             qinfo->tqi_type == AR5K_TX_QUEUE_UAPSD)
                qi->tqi_flags |= AR5K_TXQ_FLAG_POST_FR_BKOFF_DIS;

        return 0;
}

/**
 * ath5k_hw_setup_tx_queue() - Initialize a transmit queue
 * @ah: The &struct ath5k_hw
 * @queue_type: One of enum ath5k_tx_queue
 * @queue_info: The &struct ath5k_txq_info to use
 *
 * Returns 0 on success, -EINVAL on invalid arguments
 */
int
ath5k_hw_setup_tx_queue(struct ath5k_hw *ah, enum ath5k_tx_queue queue_type,
                struct ath5k_txq_info *queue_info)
{
        unsigned int queue;
        int ret;

        /*
         * Get queue by type
         */
        /* 5210 only has 2 queues */
        if (ah->ah_capabilities.cap_queues.q_tx_num == 2) {
                switch (queue_type) {
                case AR5K_TX_QUEUE_DATA:
                        queue = AR5K_TX_QUEUE_ID_NOQCU_DATA;
                        break;
                case AR5K_TX_QUEUE_BEACON:
                case AR5K_TX_QUEUE_CAB:
                        queue = AR5K_TX_QUEUE_ID_NOQCU_BEACON;
                        break;
                default:
                        return -EINVAL;
                }
        } else {
                switch (queue_type) {
                case AR5K_TX_QUEUE_DATA:
                        queue = queue_info->tqi_subtype;
                        break;
                case AR5K_TX_QUEUE_UAPSD:
                        queue = AR5K_TX_QUEUE_ID_UAPSD;
                        break;
                case AR5K_TX_QUEUE_BEACON:
                        queue = AR5K_TX_QUEUE_ID_BEACON;
                        break;
                case AR5K_TX_QUEUE_CAB:
                        queue = AR5K_TX_QUEUE_ID_CAB;
                        break;
                default:
                        return -EINVAL;
                }
        }

        /*
         * Setup internal queue structure
         */
        memset(&ah->ah_txq[queue], 0, sizeof(struct ath5k_txq_info));
        ah->ah_txq[queue].tqi_type = queue_type;

        if (queue_info != NULL) {
                queue_info->tqi_type = queue_type;
                ret = ath5k_hw_set_tx_queueprops(ah, queue, queue_info);
                if (ret)
                        return ret;
        }

        /*
         * We use ah_txq_status to hold a temp value for
         * the Secondary interrupt mask registers on 5211+
         * check out ath5k_hw_reset_tx_queue
         */
        AR5K_Q_ENABLE_BITS(ah->ah_txq_status, queue);

        return queue;
}


/*******************************\
* Single QCU/DCU initialization *
\*******************************/

/**
 * ath5k_hw_set_tx_retry_limits() - Set tx retry limits on DCU
 * @ah: The &struct ath5k_hw
 * @queue: One of enum ath5k_tx_queue_id
 *
 * This function is used when initializing a queue, to set
 * retry limits based on ah->ah_retry_* and the chipset used.
 */
void
ath5k_hw_set_tx_retry_limits(struct ath5k_hw *ah,
                                  unsigned int queue)
{
        /* Single data queue on AR5210 */
        if (ah->ah_version == AR5K_AR5210) {
                struct ath5k_txq_info *tq = &ah->ah_txq[queue];

                if (queue > 0)
                        return;

                ath5k_hw_reg_write(ah,
                        (tq->tqi_cw_min << AR5K_NODCU_RETRY_LMT_CW_MIN_S)
                        | AR5K_REG_SM(ah->ah_retry_long,
                                      AR5K_NODCU_RETRY_LMT_SLG_RETRY)
                        | AR5K_REG_SM(ah->ah_retry_short,
                                      AR5K_NODCU_RETRY_LMT_SSH_RETRY)
                        | AR5K_REG_SM(ah->ah_retry_long,
                                      AR5K_NODCU_RETRY_LMT_LG_RETRY)
                        | AR5K_REG_SM(ah->ah_retry_short,
                                      AR5K_NODCU_RETRY_LMT_SH_RETRY),
                        AR5K_NODCU_RETRY_LMT);
        /* DCU on AR5211+ */
        } else {
                ath5k_hw_reg_write(ah,
                        AR5K_REG_SM(ah->ah_retry_long,
                                    AR5K_DCU_RETRY_LMT_RTS)
                        | AR5K_REG_SM(ah->ah_retry_long,
                                      AR5K_DCU_RETRY_LMT_STA_RTS)
                        | AR5K_REG_SM(max(ah->ah_retry_long, ah->ah_retry_short),
                                      AR5K_DCU_RETRY_LMT_STA_DATA),
                        AR5K_QUEUE_DFS_RETRY_LIMIT(queue));
        }
}

/**
 * ath5k_hw_reset_tx_queue() - Initialize a single hw queue
 * @ah: The &struct ath5k_hw
 * @queue: One of enum ath5k_tx_queue_id
 *
 * Set DCF properties for the given transmit queue on DCU
 * and configures all queue-specific parameters.
 */
int
ath5k_hw_reset_tx_queue(struct ath5k_hw *ah, unsigned int queue)
{
        struct ath5k_txq_info *tq = &ah->ah_txq[queue];

        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

        /* Skip if queue inactive or if we are on AR5210
         * that doesn't have QCU/DCU */
        if ((ah->ah_version == AR5K_AR5210) ||
        (tq->tqi_type == AR5K_TX_QUEUE_INACTIVE))
                return 0;

        /*
         * Set contention window (cw_min/cw_max)
         * and arbitrated interframe space (aifs)...
         */
        ath5k_hw_reg_write(ah,
                AR5K_REG_SM(tq->tqi_cw_min, AR5K_DCU_LCL_IFS_CW_MIN) |
                AR5K_REG_SM(tq->tqi_cw_max, AR5K_DCU_LCL_IFS_CW_MAX) |
                AR5K_REG_SM(tq->tqi_aifs, AR5K_DCU_LCL_IFS_AIFS),
                AR5K_QUEUE_DFS_LOCAL_IFS(queue));

        /*
         * Set tx retry limits for this queue
         */
        ath5k_hw_set_tx_retry_limits(ah, queue);


        /*
         * Set misc registers
         */

        /* Enable DCU to wait for next fragment from QCU */
        AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
                                AR5K_DCU_MISC_FRAG_WAIT);

        /* On Maui and Spirit use the global seqnum on DCU */
        if (ah->ah_mac_version < AR5K_SREV_AR5211)
                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
                                        AR5K_DCU_MISC_SEQNUM_CTL);

        /* Constant bit rate period */
        if (tq->tqi_cbr_period) {
                ath5k_hw_reg_write(ah, AR5K_REG_SM(tq->tqi_cbr_period,
                                        AR5K_QCU_CBRCFG_INTVAL) |
                                        AR5K_REG_SM(tq->tqi_cbr_overflow_limit,
                                        AR5K_QCU_CBRCFG_ORN_THRES),
                                        AR5K_QUEUE_CBRCFG(queue));

                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                        AR5K_QCU_MISC_FRSHED_CBR);

                if (tq->tqi_cbr_overflow_limit)
                        AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                        AR5K_QCU_MISC_CBR_THRES_ENABLE);
        }

        /* Ready time interval */
        if (tq->tqi_ready_time && (tq->tqi_type != AR5K_TX_QUEUE_CAB))
                ath5k_hw_reg_write(ah, AR5K_REG_SM(tq->tqi_ready_time,
                                        AR5K_QCU_RDYTIMECFG_INTVAL) |
                                        AR5K_QCU_RDYTIMECFG_ENABLE,
                                        AR5K_QUEUE_RDYTIMECFG(queue));

        if (tq->tqi_burst_time) {
                ath5k_hw_reg_write(ah, AR5K_REG_SM(tq->tqi_burst_time,
                                        AR5K_DCU_CHAN_TIME_DUR) |
                                        AR5K_DCU_CHAN_TIME_ENABLE,
                                        AR5K_QUEUE_DFS_CHANNEL_TIME(queue));

                if (tq->tqi_flags & AR5K_TXQ_FLAG_RDYTIME_EXP_POLICY_ENABLE)
                        AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                        AR5K_QCU_MISC_RDY_VEOL_POLICY);
        }

        /* Enable/disable Post frame backoff */
        if (tq->tqi_flags & AR5K_TXQ_FLAG_BACKOFF_DISABLE)
                ath5k_hw_reg_write(ah, AR5K_DCU_MISC_POST_FR_BKOFF_DIS,
                                        AR5K_QUEUE_DFS_MISC(queue));

        /* Enable/disable fragmentation burst backoff */
        if (tq->tqi_flags & AR5K_TXQ_FLAG_FRAG_BURST_BACKOFF_ENABLE)
                ath5k_hw_reg_write(ah, AR5K_DCU_MISC_BACKOFF_FRAG,
                                        AR5K_QUEUE_DFS_MISC(queue));

        /*
         * Set registers by queue type
         */
        switch (tq->tqi_type) {
        case AR5K_TX_QUEUE_BEACON:
                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                AR5K_QCU_MISC_FRSHED_DBA_GT |
                                AR5K_QCU_MISC_CBREXP_BCN_DIS |
                                AR5K_QCU_MISC_BCN_ENABLE);

                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
                                (AR5K_DCU_MISC_ARBLOCK_CTL_GLOBAL <<
                                AR5K_DCU_MISC_ARBLOCK_CTL_S) |
                                AR5K_DCU_MISC_ARBLOCK_IGNORE |
                                AR5K_DCU_MISC_POST_FR_BKOFF_DIS |
                                AR5K_DCU_MISC_BCN_ENABLE);
                break;

        case AR5K_TX_QUEUE_CAB:
                /* XXX: use BCN_SENT_GT, if we can figure out how */
                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                        AR5K_QCU_MISC_FRSHED_DBA_GT |
                                        AR5K_QCU_MISC_CBREXP_DIS |
                                        AR5K_QCU_MISC_CBREXP_BCN_DIS);

                ath5k_hw_reg_write(ah, ((tq->tqi_ready_time -
                                        (AR5K_TUNE_SW_BEACON_RESP -
                                        AR5K_TUNE_DMA_BEACON_RESP) -
                                AR5K_TUNE_ADDITIONAL_SWBA_BACKOFF) * 1024) |
                                        AR5K_QCU_RDYTIMECFG_ENABLE,
                                        AR5K_QUEUE_RDYTIMECFG(queue));

                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
                                        (AR5K_DCU_MISC_ARBLOCK_CTL_GLOBAL <<
                                        AR5K_DCU_MISC_ARBLOCK_CTL_S));
                break;

        case AR5K_TX_QUEUE_UAPSD:
                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                        AR5K_QCU_MISC_CBREXP_DIS);
                break;

        case AR5K_TX_QUEUE_DATA:
        default:
                        break;
        }

        /* TODO: Handle frame compression */

        /*
         * Enable interrupts for this tx queue
         * in the secondary interrupt mask registers
         */
        if (tq->tqi_flags & AR5K_TXQ_FLAG_TXOKINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txok, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_TXERRINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txerr, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_TXURNINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txurn, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_TXDESCINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txdesc, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_TXEOLINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txeol, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_CBRORNINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_cbrorn, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_CBRURNINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_cbrurn, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_QTRIGINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_qtrig, queue);

        if (tq->tqi_flags & AR5K_TXQ_FLAG_TXNOFRMINT_ENABLE)
                AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_nofrm, queue);

        /* Update secondary interrupt mask registers */

        /* Filter out inactive queues */
        ah->ah_txq_imr_txok &= ah->ah_txq_status;
        ah->ah_txq_imr_txerr &= ah->ah_txq_status;
        ah->ah_txq_imr_txurn &= ah->ah_txq_status;
        ah->ah_txq_imr_txdesc &= ah->ah_txq_status;
        ah->ah_txq_imr_txeol &= ah->ah_txq_status;
        ah->ah_txq_imr_cbrorn &= ah->ah_txq_status;
        ah->ah_txq_imr_cbrurn &= ah->ah_txq_status;
        ah->ah_txq_imr_qtrig &= ah->ah_txq_status;
        ah->ah_txq_imr_nofrm &= ah->ah_txq_status;

        ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_txok,
                                        AR5K_SIMR0_QCU_TXOK) |
                                        AR5K_REG_SM(ah->ah_txq_imr_txdesc,
                                        AR5K_SIMR0_QCU_TXDESC),
                                        AR5K_SIMR0);

        ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_txerr,
                                        AR5K_SIMR1_QCU_TXERR) |
                                        AR5K_REG_SM(ah->ah_txq_imr_txeol,
                                        AR5K_SIMR1_QCU_TXEOL),
                                        AR5K_SIMR1);

        /* Update SIMR2 but don't overwrite rest simr2 settings */
        AR5K_REG_DISABLE_BITS(ah, AR5K_SIMR2, AR5K_SIMR2_QCU_TXURN);
        AR5K_REG_ENABLE_BITS(ah, AR5K_SIMR2,
                                AR5K_REG_SM(ah->ah_txq_imr_txurn,
                                AR5K_SIMR2_QCU_TXURN));

        ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_cbrorn,
                                AR5K_SIMR3_QCBRORN) |
                                AR5K_REG_SM(ah->ah_txq_imr_cbrurn,
                                AR5K_SIMR3_QCBRURN),
                                AR5K_SIMR3);

        ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_qtrig,
                                AR5K_SIMR4_QTRIG), AR5K_SIMR4);

        /* Set TXNOFRM_QCU for the queues with TXNOFRM enabled */
        ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_nofrm,
                                AR5K_TXNOFRM_QCU), AR5K_TXNOFRM);

        /* No queue has TXNOFRM enabled, disable the interrupt
         * by setting AR5K_TXNOFRM to zero */
        if (ah->ah_txq_imr_nofrm == 0)
                ath5k_hw_reg_write(ah, 0, AR5K_TXNOFRM);

        /* Set QCU mask for this DCU to save power */
        AR5K_REG_WRITE_Q(ah, AR5K_QUEUE_QCUMASK(queue), queue);

        return 0;
}


/**************************\
* Global QCU/DCU functions *
\**************************/

/**
 * ath5k_hw_set_ifs_intervals()  - Set global inter-frame spaces on DCU
 * @ah: The &struct ath5k_hw
 * @slot_time: Slot time in us
 *
 * Sets the global IFS intervals on DCU (also works on AR5210) for
 * the given slot time and the current bwmode.
 */
int ath5k_hw_set_ifs_intervals(struct ath5k_hw *ah, unsigned int slot_time)
{
        struct ieee80211_channel *channel = ah->ah_current_channel;
        enum nl80211_band band;
        struct ieee80211_supported_band *sband;
        struct ieee80211_rate *rate;
        u32 ack_tx_time, eifs, eifs_clock, sifs, sifs_clock;
        u32 slot_time_clock = ath5k_hw_htoclock(ah, slot_time);
        u32 rate_flags, i;

        if (slot_time < 6 || slot_time_clock > AR5K_SLOT_TIME_MAX)
                return -EINVAL;

        sifs = ath5k_hw_get_default_sifs(ah);
        sifs_clock = ath5k_hw_htoclock(ah, sifs - 2);

        /* EIFS
         * Txtime of ack at lowest rate + SIFS + DIFS
         * (DIFS = SIFS + 2 * Slot time)
         *
         * Note: HAL has some predefined values for EIFS
         * Turbo:   (37 + 2 * 6)
         * Default: (74 + 2 * 9)
         * Half:    (149 + 2 * 13)
         * Quarter: (298 + 2 * 21)
         *
         * (74 + 2 * 6) for AR5210 default and turbo !
         *
         * According to the formula we have
         * ack_tx_time = 25 for turbo and
         * ack_tx_time = 42.5 * clock multiplier
         * for default/half/quarter.
         *
         * This can't be right, 42 is what we would get
         * from ath5k_hw_get_frame_dur_for_bwmode or
         * ieee80211_generic_frame_duration for zero frame
         * length and without SIFS !
         *
         * Also we have different lowest rate for 802.11a
         */
        if (channel->band == NL80211_BAND_5GHZ)
                band = NL80211_BAND_5GHZ;
        else
                band = NL80211_BAND_2GHZ;

        switch (ah->ah_bwmode) {
        case AR5K_BWMODE_5MHZ:
                rate_flags = IEEE80211_RATE_SUPPORTS_5MHZ;
                break;
        case AR5K_BWMODE_10MHZ:
                rate_flags = IEEE80211_RATE_SUPPORTS_10MHZ;
                break;
        default:
                rate_flags = 0;
                break;
        }
        sband = &ah->sbands[band];
        rate = NULL;
        for (i = 0; i < sband->n_bitrates; i++) {
                if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
                        continue;
                rate = &sband->bitrates[i];
                break;
        }
        if (WARN_ON(!rate))
                return -EINVAL;

        ack_tx_time = ath5k_hw_get_frame_duration(ah, band, 10, rate, false);

        /* ack_tx_time includes an SIFS already */
        eifs = ack_tx_time + sifs + 2 * slot_time;
        eifs_clock = ath5k_hw_htoclock(ah, eifs);

        /* Set IFS settings on AR5210 */
        if (ah->ah_version == AR5K_AR5210) {
                u32 pifs, pifs_clock, difs, difs_clock;

                /* Set slot time */
                ath5k_hw_reg_write(ah, slot_time_clock, AR5K_SLOT_TIME);

                /* Set EIFS */
                eifs_clock = AR5K_REG_SM(eifs_clock, AR5K_IFS1_EIFS);

                /* PIFS = Slot time + SIFS */
                pifs = slot_time + sifs;
                pifs_clock = ath5k_hw_htoclock(ah, pifs);
                pifs_clock = AR5K_REG_SM(pifs_clock, AR5K_IFS1_PIFS);

                /* DIFS = SIFS + 2 * Slot time */
                difs = sifs + 2 * slot_time;
                difs_clock = ath5k_hw_htoclock(ah, difs);

                /* Set SIFS/DIFS */
                ath5k_hw_reg_write(ah, (difs_clock <<
                                AR5K_IFS0_DIFS_S) | sifs_clock,
                                AR5K_IFS0);

                /* Set PIFS/EIFS and preserve AR5K_INIT_CARR_SENSE_EN */
                ath5k_hw_reg_write(ah, pifs_clock | eifs_clock |
                                (AR5K_INIT_CARR_SENSE_EN << AR5K_IFS1_CS_EN_S),
                                AR5K_IFS1);

                return 0;
        }

        /* Set IFS slot time */
        ath5k_hw_reg_write(ah, slot_time_clock, AR5K_DCU_GBL_IFS_SLOT);

        /* Set EIFS interval */
        ath5k_hw_reg_write(ah, eifs_clock, AR5K_DCU_GBL_IFS_EIFS);

        /* Set SIFS interval in usecs */
        AR5K_REG_WRITE_BITS(ah, AR5K_DCU_GBL_IFS_MISC,
                                AR5K_DCU_GBL_IFS_MISC_SIFS_DUR_USEC,
                                sifs);

        /* Set SIFS interval in clock cycles */
        ath5k_hw_reg_write(ah, sifs_clock, AR5K_DCU_GBL_IFS_SIFS);

        return 0;
}


/**
 * ath5k_hw_init_queues() - Initialize tx queues
 * @ah: The &struct ath5k_hw
 *
 * Initializes all tx queues based on information on
 * ah->ah_txq* set by the driver
 */
int
ath5k_hw_init_queues(struct ath5k_hw *ah)
{
        int i, ret;

        /* TODO: HW Compression support for data queues */
        /* TODO: Burst prefetch for data queues */

        /*
         * Reset queues and start beacon timers at the end of the reset routine
         * This also sets QCU mask on each DCU for 1:1 qcu to dcu mapping
         * Note: If we want we can assign multiple qcus on one dcu.
         */
        if (ah->ah_version != AR5K_AR5210)
                for (i = 0; i < ah->ah_capabilities.cap_queues.q_tx_num; i++) {
                        ret = ath5k_hw_reset_tx_queue(ah, i);
                        if (ret) {
                                ATH5K_ERR(ah,
                                        "failed to reset TX queue #%d\n", i);
                                return ret;
                        }
                }
        else
                /* No QCU/DCU on AR5210, just set tx
                 * retry limits. We set IFS parameters
                 * on ath5k_hw_set_ifs_intervals */
                ath5k_hw_set_tx_retry_limits(ah, 0);

        /* Set the turbo flag when operating on 40MHz */
        if (ah->ah_bwmode == AR5K_BWMODE_40MHZ)
                AR5K_REG_ENABLE_BITS(ah, AR5K_DCU_GBL_IFS_MISC,
                                AR5K_DCU_GBL_IFS_MISC_TURBO_MODE);

        /* If we didn't set IFS timings through
         * ath5k_hw_set_coverage_class make sure
         * we set them here */
        if (!ah->ah_coverage_class) {
                unsigned int slot_time = ath5k_hw_get_default_slottime(ah);
                ath5k_hw_set_ifs_intervals(ah, slot_time);
        }

        return 0;
}