[safe/jmp/linux-2.6] / drivers / net / wireless / iwlwifi / iwl-tx.c

/******************************************************************************
 *
 * Copyright(c) 2003 - 2009 Intel Corporation. All rights reserved.
 *
 * Portions of this file are derived from the ipw3945 project, as well
 * as portions of the ieee80211 subsystem header files.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
 *
 * The full GNU General Public License is included in this distribution in the
 * file called LICENSE.
 *
 * Contact Information:
 *  Intel Linux Wireless <ilw@linux.intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 *****************************************************************************/

#include <linux/etherdevice.h>
#include <net/mac80211.h>
#include "iwl-eeprom.h"
#include "iwl-dev.h"
#include "iwl-core.h"
#include "iwl-sta.h"
#include "iwl-io.h"
#include "iwl-helpers.h"

static const u16 default_tid_to_tx_fifo[] = {
        IWL_TX_FIFO_AC1,
        IWL_TX_FIFO_AC0,
        IWL_TX_FIFO_AC0,
        IWL_TX_FIFO_AC1,
        IWL_TX_FIFO_AC2,
        IWL_TX_FIFO_AC2,
        IWL_TX_FIFO_AC3,
        IWL_TX_FIFO_AC3,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_NONE,
        IWL_TX_FIFO_AC3
};

static inline int iwl_alloc_dma_ptr(struct iwl_priv *priv,
                                    struct iwl_dma_ptr *ptr, size_t size)
{
        ptr->addr = pci_alloc_consistent(priv->pci_dev, size, &ptr->dma);
        if (!ptr->addr)
                return -ENOMEM;
        ptr->size = size;
        return 0;
}

static inline void iwl_free_dma_ptr(struct iwl_priv *priv,
                                    struct iwl_dma_ptr *ptr)
{
        if (unlikely(!ptr->addr))
                return;

        pci_free_consistent(priv->pci_dev, ptr->size, ptr->addr, ptr->dma);
        memset(ptr, 0, sizeof(*ptr));
}

/**
 * iwl_txq_update_write_ptr - Send new write index to hardware
 */
int iwl_txq_update_write_ptr(struct iwl_priv *priv, struct iwl_tx_queue *txq)
{
        u32 reg = 0;
        int ret = 0;
        int txq_id = txq->q.id;

        if (txq->need_update == 0)
                return ret;

        /* if we're trying to save power */
        if (test_bit(STATUS_POWER_PMI, &priv->status)) {
                /* wake up nic if it's powered down ...
                 * uCode will wake up, and interrupt us again, so next
                 * time we'll skip this part. */
                reg = iwl_read32(priv, CSR_UCODE_DRV_GP1);

                if (reg & CSR_UCODE_DRV_GP1_BIT_MAC_SLEEP) {
                        IWL_DEBUG_INFO(priv, "Requesting wakeup, GP1 = 0x%x\n", reg);
                        iwl_set_bit(priv, CSR_GP_CNTRL,
                                    CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
                        return ret;
                }

                iwl_write_direct32(priv, HBUS_TARG_WRPTR,
                                     txq->q.write_ptr | (txq_id << 8));

        /* else not in power-save mode, uCode will never sleep when we're
         * trying to tx (during RFKILL, we're not trying to tx). */
        } else
                iwl_write32(priv, HBUS_TARG_WRPTR,
                            txq->q.write_ptr | (txq_id << 8));

        txq->need_update = 0;

        return ret;
}
EXPORT_SYMBOL(iwl_txq_update_write_ptr);


/**
 * iwl_tx_queue_free - Deallocate DMA queue.
 * @txq: Transmit queue to deallocate.
 *
 * Empty queue by removing and destroying all BD's.
 * Free all buffers.
 * 0-fill, but do not free "txq" descriptor structure.
 */
void iwl_tx_queue_free(struct iwl_priv *priv, int txq_id)
{
        struct iwl_tx_queue *txq = &priv->txq[txq_id];
        struct iwl_queue *q = &txq->q;
        struct pci_dev *dev = priv->pci_dev;
        int i, len;

        if (q->n_bd == 0)
                return;

        /* first, empty all BD's */
        for (; q->write_ptr != q->read_ptr;
             q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd))
                priv->cfg->ops->lib->txq_free_tfd(priv, txq);

        len = sizeof(struct iwl_device_cmd) * q->n_window;

        /* De-alloc array of command/tx buffers */
        for (i = 0; i < TFD_TX_CMD_SLOTS; i++)
                kfree(txq->cmd[i]);

        /* De-alloc circular buffer of TFDs */
        if (txq->q.n_bd)
                pci_free_consistent(dev, priv->hw_params.tfd_size *
                                    txq->q.n_bd, txq->tfds, txq->q.dma_addr);

        /* De-alloc array of per-TFD driver data */
        kfree(txq->txb);
        txq->txb = NULL;

        /* deallocate arrays */
        kfree(txq->cmd);
        kfree(txq->meta);
        txq->cmd = NULL;
        txq->meta = NULL;

        /* 0-fill queue descriptor structure */
        memset(txq, 0, sizeof(*txq));
}
EXPORT_SYMBOL(iwl_tx_queue_free);

/**
 * iwl_cmd_queue_free - Deallocate DMA queue.
 * @txq: Transmit queue to deallocate.
 *
 * Empty queue by removing and destroying all BD's.
 * Free all buffers.
 * 0-fill, but do not free "txq" descriptor structure.
 */
void iwl_cmd_queue_free(struct iwl_priv *priv)
{
        struct iwl_tx_queue *txq = &priv->txq[IWL_CMD_QUEUE_NUM];
        struct iwl_queue *q = &txq->q;
        struct pci_dev *dev = priv->pci_dev;
        int i, len;

        if (q->n_bd == 0)
                return;

        len = sizeof(struct iwl_device_cmd) * q->n_window;
        len += IWL_MAX_SCAN_SIZE;

        /* De-alloc array of command/tx buffers */
        for (i = 0; i <= TFD_CMD_SLOTS; i++)
                kfree(txq->cmd[i]);

        /* De-alloc circular buffer of TFDs */
        if (txq->q.n_bd)
                pci_free_consistent(dev, priv->hw_params.tfd_size *
                                    txq->q.n_bd, txq->tfds, txq->q.dma_addr);

        /* deallocate arrays */
        kfree(txq->cmd);
        kfree(txq->meta);
        txq->cmd = NULL;
        txq->meta = NULL;

        /* 0-fill queue descriptor structure */
        memset(txq, 0, sizeof(*txq));
}
EXPORT_SYMBOL(iwl_cmd_queue_free);

/*************** DMA-QUEUE-GENERAL-FUNCTIONS  *****
 * DMA services
 *
 * Theory of operation
 *
 * A Tx or Rx queue resides in host DRAM, and is comprised of a circular buffer
 * of buffer descriptors, each of which points to one or more data buffers for
 * the device to read from or fill.  Driver and device exchange status of each
 * queue via "read" and "write" pointers.  Driver keeps minimum of 2 empty
 * entries in each circular buffer, to protect against confusing empty and full
 * queue states.
 *
 * The device reads or writes the data in the queues via the device's several
 * DMA/FIFO channels.  Each queue is mapped to a single DMA channel.
 *
 * For Tx queue, there are low mark and high mark limits. If, after queuing
 * the packet for Tx, free space become < low mark, Tx queue stopped. When
 * reclaiming packets (on 'tx done IRQ), if free space become > high mark,
 * Tx queue resumed.
 *
 * See more detailed info in iwl-4965-hw.h.
 ***************************************************/

int iwl_queue_space(const struct iwl_queue *q)
{
        int s = q->read_ptr - q->write_ptr;

        if (q->read_ptr > q->write_ptr)
                s -= q->n_bd;

        if (s <= 0)
                s += q->n_window;
        /* keep some reserve to not confuse empty and full situations */
        s -= 2;
        if (s < 0)
                s = 0;
        return s;
}
EXPORT_SYMBOL(iwl_queue_space);


/**
 * iwl_queue_init - Initialize queue's high/low-water and read/write indexes
 */
static int iwl_queue_init(struct iwl_priv *priv, struct iwl_queue *q,
                          int count, int slots_num, u32 id)
{
        q->n_bd = count;
        q->n_window = slots_num;
        q->id = id;

        /* count must be power-of-two size, otherwise iwl_queue_inc_wrap
         * and iwl_queue_dec_wrap are broken. */
        BUG_ON(!is_power_of_2(count));

        /* slots_num must be power-of-two size, otherwise
         * get_cmd_index is broken. */
        BUG_ON(!is_power_of_2(slots_num));

        q->low_mark = q->n_window / 4;
        if (q->low_mark < 4)
                q->low_mark = 4;

        q->high_mark = q->n_window / 8;
        if (q->high_mark < 2)
                q->high_mark = 2;

        q->write_ptr = q->read_ptr = 0;

        return 0;
}

/**
 * iwl_tx_queue_alloc - Alloc driver data and TFD CB for one Tx/cmd queue
 */
static int iwl_tx_queue_alloc(struct iwl_priv *priv,
                              struct iwl_tx_queue *txq, u32 id)
{
        struct pci_dev *dev = priv->pci_dev;
        size_t tfd_sz = priv->hw_params.tfd_size * TFD_QUEUE_SIZE_MAX;

        /* Driver private data, only for Tx (not command) queues,
         * not shared with device. */
        if (id != IWL_CMD_QUEUE_NUM) {
                txq->txb = kmalloc(sizeof(txq->txb[0]) *
                                   TFD_QUEUE_SIZE_MAX, GFP_KERNEL);
                if (!txq->txb) {
                        IWL_ERR(priv, "kmalloc for auxiliary BD "
                                  "structures failed\n");
                        goto error;
                }
        } else {
                txq->txb = NULL;
        }

        /* Circular buffer of transmit frame descriptors (TFDs),
         * shared with device */
        txq->tfds = pci_alloc_consistent(dev, tfd_sz, &txq->q.dma_addr);

        if (!txq->tfds) {
                IWL_ERR(priv, "pci_alloc_consistent(%zd) failed\n", tfd_sz);
                goto error;
        }
        txq->q.id = id;

        return 0;

 error:
        kfree(txq->txb);
        txq->txb = NULL;

        return -ENOMEM;
}

/**
 * iwl_tx_queue_init - Allocate and initialize one tx/cmd queue
 */
int iwl_tx_queue_init(struct iwl_priv *priv, struct iwl_tx_queue *txq,
                      int slots_num, u32 txq_id)
{
        int i, len;
        int ret;
        int actual_slots = slots_num;

        /*
         * Alloc buffer array for commands (Tx or other types of commands).
         * For the command queue (#4), allocate command space + one big
         * command for scan, since scan command is very huge; the system will
         * not have two scans at the same time, so only one is needed.
         * For normal Tx queues (all other queues), no super-size command
         * space is needed.
         */
        if (txq_id == IWL_CMD_QUEUE_NUM)
                actual_slots++;

        txq->meta = kzalloc(sizeof(struct iwl_cmd_meta) * actual_slots,
                            GFP_KERNEL);
        txq->cmd = kzalloc(sizeof(struct iwl_device_cmd *) * actual_slots,
                           GFP_KERNEL);

        if (!txq->meta || !txq->cmd)
                goto out_free_arrays;

        len = sizeof(struct iwl_device_cmd);
        for (i = 0; i < actual_slots; i++) {
                /* only happens for cmd queue */
                if (i == slots_num)
                        len += IWL_MAX_SCAN_SIZE;

                txq->cmd[i] = kmalloc(len, GFP_KERNEL);
                if (!txq->cmd[i])
                        goto err;
        }

        /* Alloc driver data array and TFD circular buffer */
        ret = iwl_tx_queue_alloc(priv, txq, txq_id);
        if (ret)
                goto err;

        txq->need_update = 0;

        /* aggregation TX queues will get their ID when aggregation begins */
        if (txq_id <= IWL_TX_FIFO_AC3)
                txq->swq_id = txq_id;

        /* TFD_QUEUE_SIZE_MAX must be power-of-two size, otherwise
         * iwl_queue_inc_wrap and iwl_queue_dec_wrap are broken. */
        BUILD_BUG_ON(TFD_QUEUE_SIZE_MAX & (TFD_QUEUE_SIZE_MAX - 1));

        /* Initialize queue's high/low-water marks, and head/tail indexes */
        iwl_queue_init(priv, &txq->q, TFD_QUEUE_SIZE_MAX, slots_num, txq_id);

        /* Tell device where to find queue */
        priv->cfg->ops->lib->txq_init(priv, txq);

        return 0;
err:
        for (i = 0; i < actual_slots; i++)
                kfree(txq->cmd[i]);
out_free_arrays:
        kfree(txq->meta);
        kfree(txq->cmd);

        return -ENOMEM;
}
EXPORT_SYMBOL(iwl_tx_queue_init);

/**
 * iwl_hw_txq_ctx_free - Free TXQ Context
 *
 * Destroy all TX DMA queues and structures
 */
void iwl_hw_txq_ctx_free(struct iwl_priv *priv)
{
        int txq_id;

        /* Tx queues */
        for (txq_id = 0; txq_id < priv->hw_params.max_txq_num; txq_id++)
                if (txq_id == IWL_CMD_QUEUE_NUM)
                        iwl_cmd_queue_free(priv);
                else
                        iwl_tx_queue_free(priv, txq_id);

        iwl_free_dma_ptr(priv, &priv->kw);

        iwl_free_dma_ptr(priv, &priv->scd_bc_tbls);
}
EXPORT_SYMBOL(iwl_hw_txq_ctx_free);

/**
 * iwl_txq_ctx_reset - Reset TX queue context
 * Destroys all DMA structures and initialize them again
 *
 * @param priv
 * @return error code
 */
int iwl_txq_ctx_reset(struct iwl_priv *priv)
{
        int ret = 0;
        int txq_id, slots_num;
        unsigned long flags;

        /* Free all tx/cmd queues and keep-warm buffer */
        iwl_hw_txq_ctx_free(priv);

        ret = iwl_alloc_dma_ptr(priv, &priv->scd_bc_tbls,
                                priv->hw_params.scd_bc_tbls_size);
        if (ret) {
                IWL_ERR(priv, "Scheduler BC Table allocation failed\n");
                goto error_bc_tbls;
        }
        /* Alloc keep-warm buffer */
        ret = iwl_alloc_dma_ptr(priv, &priv->kw, IWL_KW_SIZE);
        if (ret) {
                IWL_ERR(priv, "Keep Warm allocation failed\n");
                goto error_kw;
        }
        spin_lock_irqsave(&priv->lock, flags);

        /* Turn off all Tx DMA fifos */
        priv->cfg->ops->lib->txq_set_sched(priv, 0);

        /* Tell NIC where to find the "keep warm" buffer */
        iwl_write_direct32(priv, FH_KW_MEM_ADDR_REG, priv->kw.dma >> 4);

        spin_unlock_irqrestore(&priv->lock, flags);

        /* Alloc and init all Tx queues, including the command queue (#4) */
        for (txq_id = 0; txq_id < priv->hw_params.max_txq_num; txq_id++) {
                slots_num = (txq_id == IWL_CMD_QUEUE_NUM) ?
                                        TFD_CMD_SLOTS : TFD_TX_CMD_SLOTS;
                ret = iwl_tx_queue_init(priv, &priv->txq[txq_id], slots_num,
                                       txq_id);
                if (ret) {
                        IWL_ERR(priv, "Tx %d queue init failed\n", txq_id);
                        goto error;
                }
        }

        return ret;

 error:
        iwl_hw_txq_ctx_free(priv);
        iwl_free_dma_ptr(priv, &priv->kw);
 error_kw:
        iwl_free_dma_ptr(priv, &priv->scd_bc_tbls);
 error_bc_tbls:
        return ret;
}

/**
 * iwl_txq_ctx_stop - Stop all Tx DMA channels, free Tx queue memory
 */
void iwl_txq_ctx_stop(struct iwl_priv *priv)
{
        int ch;
        unsigned long flags;

        /* Turn off all Tx DMA fifos */
        spin_lock_irqsave(&priv->lock, flags);

        priv->cfg->ops->lib->txq_set_sched(priv, 0);

        /* Stop each Tx DMA channel, and wait for it to be idle */
        for (ch = 0; ch < priv->hw_params.dma_chnl_num; ch++) {
                iwl_write_direct32(priv, FH_TCSR_CHNL_TX_CONFIG_REG(ch), 0x0);
                iwl_poll_direct_bit(priv, FH_TSSR_TX_STATUS_REG,
                                    FH_TSSR_TX_STATUS_REG_MSK_CHNL_IDLE(ch),
                                    1000);
        }
        spin_unlock_irqrestore(&priv->lock, flags);

        /* Deallocate memory for all Tx queues */
        iwl_hw_txq_ctx_free(priv);
}
EXPORT_SYMBOL(iwl_txq_ctx_stop);

/*
 * handle build REPLY_TX command notification.
 */
static void iwl_tx_cmd_build_basic(struct iwl_priv *priv,
                                  struct iwl_tx_cmd *tx_cmd,
                                  struct ieee80211_tx_info *info,
                                  struct ieee80211_hdr *hdr,
                                  u8 std_id)
{
        __le16 fc = hdr->frame_control;
        __le32 tx_flags = tx_cmd->tx_flags;

        tx_cmd->stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;
        if (!(info->flags & IEEE80211_TX_CTL_NO_ACK)) {
                tx_flags |= TX_CMD_FLG_ACK_MSK;
                if (ieee80211_is_mgmt(fc))
                        tx_flags |= TX_CMD_FLG_SEQ_CTL_MSK;
                if (ieee80211_is_probe_resp(fc) &&
                    !(le16_to_cpu(hdr->seq_ctrl) & 0xf))
                        tx_flags |= TX_CMD_FLG_TSF_MSK;
        } else {
                tx_flags &= (~TX_CMD_FLG_ACK_MSK);
                tx_flags |= TX_CMD_FLG_SEQ_CTL_MSK;
        }

        if (ieee80211_is_back_req(fc))
                tx_flags |= TX_CMD_FLG_ACK_MSK | TX_CMD_FLG_IMM_BA_RSP_MASK;


        tx_cmd->sta_id = std_id;
        if (ieee80211_has_morefrags(fc))
                tx_flags |= TX_CMD_FLG_MORE_FRAG_MSK;

        if (ieee80211_is_data_qos(fc)) {
                u8 *qc = ieee80211_get_qos_ctl(hdr);
                tx_cmd->tid_tspec = qc[0] & 0xf;
                tx_flags &= ~TX_CMD_FLG_SEQ_CTL_MSK;
        } else {
                tx_flags |= TX_CMD_FLG_SEQ_CTL_MSK;
        }

        priv->cfg->ops->utils->rts_tx_cmd_flag(info, &tx_flags);

        if ((tx_flags & TX_CMD_FLG_RTS_MSK) || (tx_flags & TX_CMD_FLG_CTS_MSK))
                tx_flags |= TX_CMD_FLG_FULL_TXOP_PROT_MSK;

        tx_flags &= ~(TX_CMD_FLG_ANT_SEL_MSK);
        if (ieee80211_is_mgmt(fc)) {
                if (ieee80211_is_assoc_req(fc) || ieee80211_is_reassoc_req(fc))
                        tx_cmd->timeout.pm_frame_timeout = cpu_to_le16(3);
                else
                        tx_cmd->timeout.pm_frame_timeout = cpu_to_le16(2);
        } else {
                tx_cmd->timeout.pm_frame_timeout = 0;
        }

        tx_cmd->driver_txop = 0;
        tx_cmd->tx_flags = tx_flags;
        tx_cmd->next_frame_len = 0;
}

#define RTS_HCCA_RETRY_LIMIT            3
#define RTS_DFAULT_RETRY_LIMIT          60

static void iwl_tx_cmd_build_rate(struct iwl_priv *priv,
                              struct iwl_tx_cmd *tx_cmd,
                              struct ieee80211_tx_info *info,
                              __le16 fc, int is_hcca)
{
        u32 rate_flags;
        int rate_idx;
        u8 rts_retry_limit;
        u8 data_retry_limit;
        u8 rate_plcp;

        /* Set retry limit on DATA packets and Probe Responses*/
        if (priv->data_retry_limit != -1)
                data_retry_limit = priv->data_retry_limit;
        else if (ieee80211_is_probe_resp(fc))
                data_retry_limit = 3;
        else
                data_retry_limit = IWL_DEFAULT_TX_RETRY;
        tx_cmd->data_retry_limit = data_retry_limit;

        /* Set retry limit on RTS packets */
        rts_retry_limit = (is_hcca) ?  RTS_HCCA_RETRY_LIMIT :
                RTS_DFAULT_RETRY_LIMIT;
        if (data_retry_limit < rts_retry_limit)
                rts_retry_limit = data_retry_limit;
        tx_cmd->rts_retry_limit = rts_retry_limit;

        /* DATA packets will use the uCode station table for rate/antenna
         * selection */
        if (ieee80211_is_data(fc)) {
                tx_cmd->initial_rate_index = 0;
                tx_cmd->tx_flags |= TX_CMD_FLG_STA_RATE_MSK;
                return;
        }

        /**
         * If the current TX rate stored in mac80211 has the MCS bit set, it's
         * not really a TX rate.  Thus, we use the lowest supported rate for
         * this band.  Also use the lowest supported rate if the stored rate
         * index is invalid.
         */
        rate_idx = info->control.rates[0].idx;
        if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS ||
                        (rate_idx < 0) || (rate_idx > IWL_RATE_COUNT_LEGACY))
                rate_idx = rate_lowest_index(&priv->bands[info->band],
                                info->control.sta);
        /* For 5 GHZ band, remap mac80211 rate indices into driver indices */
        if (info->band == IEEE80211_BAND_5GHZ)
                rate_idx += IWL_FIRST_OFDM_RATE;
        /* Get PLCP rate for tx_cmd->rate_n_flags */
        rate_plcp = iwl_rates[rate_idx].plcp;
        /* Zero out flags for this packet */
        rate_flags = 0;

        /* Set CCK flag as needed */
        if ((rate_idx >= IWL_FIRST_CCK_RATE) && (rate_idx <= IWL_LAST_CCK_RATE))
                rate_flags |= RATE_MCS_CCK_MSK;

        /* Set up RTS and CTS flags for certain packets */
        switch (fc & cpu_to_le16(IEEE80211_FCTL_STYPE)) {
        case cpu_to_le16(IEEE80211_STYPE_AUTH):
        case cpu_to_le16(IEEE80211_STYPE_DEAUTH):
        case cpu_to_le16(IEEE80211_STYPE_ASSOC_REQ):
        case cpu_to_le16(IEEE80211_STYPE_REASSOC_REQ):
                if (tx_cmd->tx_flags & TX_CMD_FLG_RTS_MSK) {
                        tx_cmd->tx_flags &= ~TX_CMD_FLG_RTS_MSK;
                        tx_cmd->tx_flags |= TX_CMD_FLG_CTS_MSK;
                }
                break;
        default:
                break;
        }

        /* Set up antennas */
        priv->mgmt_tx_ant = iwl_toggle_tx_ant(priv, priv->mgmt_tx_ant);
        rate_flags |= iwl_ant_idx_to_flags(priv->mgmt_tx_ant);

        /* Set the rate in the TX cmd */
        tx_cmd->rate_n_flags = iwl_hw_set_rate_n_flags(rate_plcp, rate_flags);
}

static void iwl_tx_cmd_build_hwcrypto(struct iwl_priv *priv,
                                      struct ieee80211_tx_info *info,
                                      struct iwl_tx_cmd *tx_cmd,
                                      struct sk_buff *skb_frag,
                                      int sta_id)
{
        struct ieee80211_key_conf *keyconf = info->control.hw_key;

        switch (keyconf->alg) {
        case ALG_CCMP:
                tx_cmd->sec_ctl = TX_CMD_SEC_CCM;
                memcpy(tx_cmd->key, keyconf->key, keyconf->keylen);
                if (info->flags & IEEE80211_TX_CTL_AMPDU)
                        tx_cmd->tx_flags |= TX_CMD_FLG_AGG_CCMP_MSK;
                IWL_DEBUG_TX(priv, "tx_cmd with AES hwcrypto\n");
                break;

        case ALG_TKIP:
                tx_cmd->sec_ctl = TX_CMD_SEC_TKIP;
                ieee80211_get_tkip_key(keyconf, skb_frag,
                        IEEE80211_TKIP_P2_KEY, tx_cmd->key);
                IWL_DEBUG_TX(priv, "tx_cmd with tkip hwcrypto\n");
                break;

        case ALG_WEP:
                tx_cmd->sec_ctl |= (TX_CMD_SEC_WEP |
                        (keyconf->keyidx & TX_CMD_SEC_MSK) << TX_CMD_SEC_SHIFT);

                if (keyconf->keylen == WEP_KEY_LEN_128)
                        tx_cmd->sec_ctl |= TX_CMD_SEC_KEY128;

                memcpy(&tx_cmd->key[3], keyconf->key, keyconf->keylen);

                IWL_DEBUG_TX(priv, "Configuring packet for WEP encryption "
                             "with key %d\n", keyconf->keyidx);
                break;

        default:
                IWL_ERR(priv, "Unknown encode alg %d\n", keyconf->alg);
                break;
        }
}

/*
 * start REPLY_TX command process
 */
int iwl_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct iwl_tx_queue *txq;
        struct iwl_queue *q;
        struct iwl_device_cmd *out_cmd;
        struct iwl_cmd_meta *out_meta;
        struct iwl_tx_cmd *tx_cmd;
        int swq_id, txq_id;
        dma_addr_t phys_addr;
        dma_addr_t txcmd_phys;
        dma_addr_t scratch_phys;
        u16 len, len_org;
        u16 seq_number = 0;
        __le16 fc;
        u8 hdr_len;
        u8 sta_id;
        u8 wait_write_ptr = 0;
        u8 tid = 0;
        u8 *qc = NULL;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&priv->lock, flags);
        if (iwl_is_rfkill(priv)) {
                IWL_DEBUG_DROP(priv, "Dropping - RF KILL\n");
                goto drop_unlock;
        }

        fc = hdr->frame_control;

#ifdef CONFIG_IWLWIFI_DEBUG
        if (ieee80211_is_auth(fc))
                IWL_DEBUG_TX(priv, "Sending AUTH frame\n");
        else if (ieee80211_is_assoc_req(fc))
                IWL_DEBUG_TX(priv, "Sending ASSOC frame\n");
        else if (ieee80211_is_reassoc_req(fc))
                IWL_DEBUG_TX(priv, "Sending REASSOC frame\n");
#endif

        /* drop all non-injected data frame if we are not associated */
        if (ieee80211_is_data(fc) &&
            !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
            (!iwl_is_associated(priv) ||
             ((priv->iw_mode == NL80211_IFTYPE_STATION) && !priv->assoc_id) ||
             !priv->assoc_station_added)) {
                IWL_DEBUG_DROP(priv, "Dropping - !iwl_is_associated\n");
                goto drop_unlock;
        }

        hdr_len = ieee80211_hdrlen(fc);

        /* Find (or create) index into station table for destination station */
        if (info->flags & IEEE80211_TX_CTL_INJECTED)
                sta_id = priv->hw_params.bcast_sta_id;
        else
                sta_id = iwl_get_sta_id(priv, hdr);
        if (sta_id == IWL_INVALID_STATION) {
                IWL_DEBUG_DROP(priv, "Dropping - INVALID STATION: %pM\n",
                               hdr->addr1);
                goto drop_unlock;
        }

        IWL_DEBUG_TX(priv, "station Id %d\n", sta_id);

        txq_id = skb_get_queue_mapping(skb);
        if (ieee80211_is_data_qos(fc)) {
                qc = ieee80211_get_qos_ctl(hdr);
                tid = qc[0] & IEEE80211_QOS_CTL_TID_MASK;
                if (unlikely(tid >= MAX_TID_COUNT))
                        goto drop_unlock;
                seq_number = priv->stations[sta_id].tid[tid].seq_number;
                seq_number &= IEEE80211_SCTL_SEQ;
                hdr->seq_ctrl = hdr->seq_ctrl &
                                cpu_to_le16(IEEE80211_SCTL_FRAG);
                hdr->seq_ctrl |= cpu_to_le16(seq_number);
                seq_number += 0x10;
                /* aggregation is on for this <sta,tid> */
                if (info->flags & IEEE80211_TX_CTL_AMPDU)
                        txq_id = priv->stations[sta_id].tid[tid].agg.txq_id;
        }

        txq = &priv->txq[txq_id];
        swq_id = txq->swq_id;
        q = &txq->q;

        if (unlikely(iwl_queue_space(q) < q->high_mark))
                goto drop_unlock;

        if (ieee80211_is_data_qos(fc))
                priv->stations[sta_id].tid[tid].tfds_in_queue++;

        /* Set up driver data for this TFD */
        memset(&(txq->txb[q->write_ptr]), 0, sizeof(struct iwl_tx_info));
        txq->txb[q->write_ptr].skb[0] = skb;

        /* Set up first empty entry in queue's array of Tx/cmd buffers */
        out_cmd = txq->cmd[q->write_ptr];
        out_meta = &txq->meta[q->write_ptr];
        tx_cmd = &out_cmd->cmd.tx;
        memset(&out_cmd->hdr, 0, sizeof(out_cmd->hdr));
        memset(tx_cmd, 0, sizeof(struct iwl_tx_cmd));

        /*
         * Set up the Tx-command (not MAC!) header.
         * Store the chosen Tx queue and TFD index within the sequence field;
         * after Tx, uCode's Tx response will return this value so driver can
         * locate the frame within the tx queue and do post-tx processing.
         */
        out_cmd->hdr.cmd = REPLY_TX;
        out_cmd->hdr.sequence = cpu_to_le16((u16)(QUEUE_TO_SEQ(txq_id) |
                                INDEX_TO_SEQ(q->write_ptr)));

        /* Copy MAC header from skb into command buffer */
        memcpy(tx_cmd->hdr, hdr, hdr_len);


        /* Total # bytes to be transmitted */
        len = (u16)skb->len;
        tx_cmd->len = cpu_to_le16(len);

        if (info->control.hw_key)
                iwl_tx_cmd_build_hwcrypto(priv, info, tx_cmd, skb, sta_id);

        /* TODO need this for burst mode later on */
        iwl_tx_cmd_build_basic(priv, tx_cmd, info, hdr, sta_id);
        iwl_dbg_log_tx_data_frame(priv, len, hdr);

        /* set is_hcca to 0; it probably will never be implemented */
        iwl_tx_cmd_build_rate(priv, tx_cmd, info, fc, 0);

        iwl_update_stats(priv, true, fc, len);
        /*
         * Use the first empty entry in this queue's command buffer array
         * to contain the Tx command and MAC header concatenated together
         * (payload data will be in another buffer).
         * Size of this varies, due to varying MAC header length.
         * If end is not dword aligned, we'll have 2 extra bytes at the end
         * of the MAC header (device reads on dword boundaries).
         * We'll tell device about this padding later.
         */
        len = sizeof(struct iwl_tx_cmd) +
                sizeof(struct iwl_cmd_header) + hdr_len;

        len_org = len;
        len = (len + 3) & ~3;

        if (len_org != len)
                len_org = 1;
        else
                len_org = 0;

        /* Tell NIC about any 2-byte padding after MAC header */
        if (len_org)
                tx_cmd->tx_flags |= TX_CMD_FLG_MH_PAD_MSK;

        /* Physical address of this Tx command's header (not MAC header!),
         * within command buffer array. */
        txcmd_phys = pci_map_single(priv->pci_dev,
                                    &out_cmd->hdr, len,
                                    PCI_DMA_BIDIRECTIONAL);
        pci_unmap_addr_set(out_meta, mapping, txcmd_phys);
        pci_unmap_len_set(out_meta, len, len);
        /* Add buffer containing Tx command and MAC(!) header to TFD's
         * first entry */
        priv->cfg->ops->lib->txq_attach_buf_to_tfd(priv, txq,
                                                   txcmd_phys, len, 1, 0);

        if (!ieee80211_has_morefrags(hdr->frame_control)) {
                txq->need_update = 1;
                if (qc)
                        priv->stations[sta_id].tid[tid].seq_number = seq_number;
        } else {
                wait_write_ptr = 1;
                txq->need_update = 0;
        }

        /* Set up TFD's 2nd entry to point directly to remainder of skb,
         * if any (802.11 null frames have no payload). */
        len = skb->len - hdr_len;
        if (len) {
                phys_addr = pci_map_single(priv->pci_dev, skb->data + hdr_len,
                                           len, PCI_DMA_TODEVICE);
                priv->cfg->ops->lib->txq_attach_buf_to_tfd(priv, txq,
                                                           phys_addr, len,
                                                           0, 0);
        }

        scratch_phys = txcmd_phys + sizeof(struct iwl_cmd_header) +
                                offsetof(struct iwl_tx_cmd, scratch);

        len = sizeof(struct iwl_tx_cmd) +
                sizeof(struct iwl_cmd_header) + hdr_len;
        /* take back ownership of DMA buffer to enable update */
        pci_dma_sync_single_for_cpu(priv->pci_dev, txcmd_phys,
                                    len, PCI_DMA_BIDIRECTIONAL);
        tx_cmd->dram_lsb_ptr = cpu_to_le32(scratch_phys);
        tx_cmd->dram_msb_ptr = iwl_get_dma_hi_addr(scratch_phys);

        IWL_DEBUG_TX(priv, "sequence nr = 0X%x \n",
                     le16_to_cpu(out_cmd->hdr.sequence));
        IWL_DEBUG_TX(priv, "tx_flags = 0X%x \n", le32_to_cpu(tx_cmd->tx_flags));
        iwl_print_hex_dump(priv, IWL_DL_TX, (u8 *)tx_cmd, sizeof(*tx_cmd));
        iwl_print_hex_dump(priv, IWL_DL_TX, (u8 *)tx_cmd->hdr, hdr_len);

        /* Set up entry for this TFD in Tx byte-count array */
        if (info->flags & IEEE80211_TX_CTL_AMPDU)
                priv->cfg->ops->lib->txq_update_byte_cnt_tbl(priv, txq,
                                                     le16_to_cpu(tx_cmd->len));

        pci_dma_sync_single_for_device(priv->pci_dev, txcmd_phys,
                                       len, PCI_DMA_BIDIRECTIONAL);

        /* Tell device the write index *just past* this latest filled TFD */
        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
        ret = iwl_txq_update_write_ptr(priv, txq);
        spin_unlock_irqrestore(&priv->lock, flags);

        if (ret)
                return ret;

        if ((iwl_queue_space(q) < q->high_mark) && priv->mac80211_registered) {
                if (wait_write_ptr) {
                        spin_lock_irqsave(&priv->lock, flags);
                        txq->need_update = 1;
                        iwl_txq_update_write_ptr(priv, txq);
                        spin_unlock_irqrestore(&priv->lock, flags);
                } else {
                        iwl_stop_queue(priv, txq->swq_id);
                }
        }

        return 0;

drop_unlock:
        spin_unlock_irqrestore(&priv->lock, flags);
        return -1;
}
EXPORT_SYMBOL(iwl_tx_skb);

/*************** HOST COMMAND QUEUE FUNCTIONS   *****/

/**
 * iwl_enqueue_hcmd - enqueue a uCode command
 * @priv: device private data point
 * @cmd: a point to the ucode command structure
 *
 * The function returns < 0 values to indicate the operation is
 * failed. On success, it turns the index (> 0) of command in the
 * command queue.
 */
int iwl_enqueue_hcmd(struct iwl_priv *priv, struct iwl_host_cmd *cmd)
{
        struct iwl_tx_queue *txq = &priv->txq[IWL_CMD_QUEUE_NUM];
        struct iwl_queue *q = &txq->q;
        struct iwl_device_cmd *out_cmd;
        struct iwl_cmd_meta *out_meta;
        dma_addr_t phys_addr;
        unsigned long flags;
        int len, ret;
        u32 idx;
        u16 fix_size;

        cmd->len = priv->cfg->ops->utils->get_hcmd_size(cmd->id, cmd->len);
        fix_size = (u16)(cmd->len + sizeof(out_cmd->hdr));

        /* If any of the command structures end up being larger than
         * the TFD_MAX_PAYLOAD_SIZE, and it sent as a 'small' command then
         * we will need to increase the size of the TFD entries */
        BUG_ON((fix_size > TFD_MAX_PAYLOAD_SIZE) &&
               !(cmd->flags & CMD_SIZE_HUGE));

        if (iwl_is_rfkill(priv)) {
                IWL_DEBUG_INFO(priv, "Not sending command - RF KILL\n");
                return -EIO;
        }

        if (iwl_queue_space(q) < ((cmd->flags & CMD_ASYNC) ? 2 : 1)) {
                IWL_ERR(priv, "No space for Tx\n");
                return -ENOSPC;
        }

        spin_lock_irqsave(&priv->hcmd_lock, flags);

        idx = get_cmd_index(q, q->write_ptr, cmd->flags & CMD_SIZE_HUGE);
        out_cmd = txq->cmd[idx];
        out_meta = &txq->meta[idx];

        memset(out_meta, 0, sizeof(*out_meta)); /* re-initialize to NULL */
        out_meta->flags = cmd->flags;
        if (cmd->flags & CMD_WANT_SKB)
                out_meta->source = cmd;
        if (cmd->flags & CMD_ASYNC)
                out_meta->callback = cmd->callback;

        out_cmd->hdr.cmd = cmd->id;
        memcpy(&out_cmd->cmd.payload, cmd->data, cmd->len);

        /* At this point, the out_cmd now has all of the incoming cmd
         * information */

        out_cmd->hdr.flags = 0;
        out_cmd->hdr.sequence = cpu_to_le16(QUEUE_TO_SEQ(IWL_CMD_QUEUE_NUM) |
                        INDEX_TO_SEQ(q->write_ptr));
        if (cmd->flags & CMD_SIZE_HUGE)
                out_cmd->hdr.sequence |= SEQ_HUGE_FRAME;
        len = sizeof(struct iwl_device_cmd);
        len += (idx == TFD_CMD_SLOTS) ?  IWL_MAX_SCAN_SIZE : 0;


#ifdef CONFIG_IWLWIFI_DEBUG
        switch (out_cmd->hdr.cmd) {
        case REPLY_TX_LINK_QUALITY_CMD:
        case SENSITIVITY_CMD:
                IWL_DEBUG_HC_DUMP(priv, "Sending command %s (#%x), seq: 0x%04X, "
                                "%d bytes at %d[%d]:%d\n",
                                get_cmd_string(out_cmd->hdr.cmd),
                                out_cmd->hdr.cmd,
                                le16_to_cpu(out_cmd->hdr.sequence), fix_size,
                                q->write_ptr, idx, IWL_CMD_QUEUE_NUM);
                                break;
        default:
                IWL_DEBUG_HC(priv, "Sending command %s (#%x), seq: 0x%04X, "
                                "%d bytes at %d[%d]:%d\n",
                                get_cmd_string(out_cmd->hdr.cmd),
                                out_cmd->hdr.cmd,
                                le16_to_cpu(out_cmd->hdr.sequence), fix_size,
                                q->write_ptr, idx, IWL_CMD_QUEUE_NUM);
        }
#endif
        txq->need_update = 1;

        if (priv->cfg->ops->lib->txq_update_byte_cnt_tbl)
                /* Set up entry in queue's byte count circular buffer */
                priv->cfg->ops->lib->txq_update_byte_cnt_tbl(priv, txq, 0);

        phys_addr = pci_map_single(priv->pci_dev, &out_cmd->hdr,
                                   fix_size, PCI_DMA_BIDIRECTIONAL);
        pci_unmap_addr_set(out_meta, mapping, phys_addr);
        pci_unmap_len_set(out_meta, len, fix_size);

        priv->cfg->ops->lib->txq_attach_buf_to_tfd(priv, txq,
                                                   phys_addr, fix_size, 1,
                                                   U32_PAD(cmd->len));

        /* Increment and update queue's write index */
        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
        ret = iwl_txq_update_write_ptr(priv, txq);

        spin_unlock_irqrestore(&priv->hcmd_lock, flags);
        return ret ? ret : idx;
}

int iwl_tx_queue_reclaim(struct iwl_priv *priv, int txq_id, int index)
{
        struct iwl_tx_queue *txq = &priv->txq[txq_id];
        struct iwl_queue *q = &txq->q;
        struct iwl_tx_info *tx_info;
        int nfreed = 0;

        if ((index >= q->n_bd) || (iwl_queue_used(q, index) == 0)) {
                IWL_ERR(priv, "Read index for DMA queue txq id (%d), index %d, "
                          "is out of range [0-%d] %d %d.\n", txq_id,
                          index, q->n_bd, q->write_ptr, q->read_ptr);
                return 0;
        }

        for (index = iwl_queue_inc_wrap(index, q->n_bd);
             q->read_ptr != index;
             q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {

                tx_info = &txq->txb[txq->q.read_ptr];
                ieee80211_tx_status_irqsafe(priv->hw, tx_info->skb[0]);
                tx_info->skb[0] = NULL;

                if (priv->cfg->ops->lib->txq_inval_byte_cnt_tbl)
                        priv->cfg->ops->lib->txq_inval_byte_cnt_tbl(priv, txq);

                priv->cfg->ops->lib->txq_free_tfd(priv, txq);
                nfreed++;
        }
        return nfreed;
}
EXPORT_SYMBOL(iwl_tx_queue_reclaim);


/**
 * iwl_hcmd_queue_reclaim - Reclaim TX command queue entries already Tx'd
 *
 * When FW advances 'R' index, all entries between old and new 'R' index
 * need to be reclaimed. As result, some free space forms.  If there is
 * enough free space (> low mark), wake the stack that feeds us.
 */
static void iwl_hcmd_queue_reclaim(struct iwl_priv *priv, int txq_id,
                                   int idx, int cmd_idx)
{
        struct iwl_tx_queue *txq = &priv->txq[txq_id];
        struct iwl_queue *q = &txq->q;
        int nfreed = 0;

        if ((idx >= q->n_bd) || (iwl_queue_used(q, idx) == 0)) {
                IWL_ERR(priv, "Read index for DMA queue txq id (%d), index %d, "
                          "is out of range [0-%d] %d %d.\n", txq_id,
                          idx, q->n_bd, q->write_ptr, q->read_ptr);
                return;
        }

        pci_unmap_single(priv->pci_dev,
                pci_unmap_addr(&txq->meta[cmd_idx], mapping),
                pci_unmap_len(&txq->meta[cmd_idx], len),
                PCI_DMA_BIDIRECTIONAL);

        for (idx = iwl_queue_inc_wrap(idx, q->n_bd); q->read_ptr != idx;
             q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {

                if (nfreed++ > 0) {
                        IWL_ERR(priv, "HCMD skipped: index (%d) %d %d\n", idx,
                                        q->write_ptr, q->read_ptr);
                        queue_work(priv->workqueue, &priv->restart);
                }

        }
}

/**
 * iwl_tx_cmd_complete - Pull unused buffers off the queue and reclaim them
 * @rxb: Rx buffer to reclaim
 *
 * If an Rx buffer has an async callback associated with it the callback
 * will be executed.  The attached skb (if present) will only be freed
 * if the callback returns 1
 */
void iwl_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
{
        struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
        u16 sequence = le16_to_cpu(pkt->hdr.sequence);
        int txq_id = SEQ_TO_QUEUE(sequence);
        int index = SEQ_TO_INDEX(sequence);
        int cmd_index;
        bool huge = !!(pkt->hdr.sequence & SEQ_HUGE_FRAME);
        struct iwl_device_cmd *cmd;
        struct iwl_cmd_meta *meta;

        /* If a Tx command is being handled and it isn't in the actual
         * command queue then there a command routing bug has been introduced
         * in the queue management code. */
        if (WARN(txq_id != IWL_CMD_QUEUE_NUM,
                 "wrong command queue %d, sequence 0x%X readp=%d writep=%d\n",
                  txq_id, sequence,
                  priv->txq[IWL_CMD_QUEUE_NUM].q.read_ptr,
                  priv->txq[IWL_CMD_QUEUE_NUM].q.write_ptr)) {
                iwl_print_hex_error(priv, pkt, 32);
                return;
        }

        cmd_index = get_cmd_index(&priv->txq[IWL_CMD_QUEUE_NUM].q, index, huge);
        cmd = priv->txq[IWL_CMD_QUEUE_NUM].cmd[cmd_index];
        meta = &priv->txq[IWL_CMD_QUEUE_NUM].meta[cmd_index];

        /* Input error checking is done when commands are added to queue. */
        if (meta->flags & CMD_WANT_SKB) {
                meta->source->reply_skb = rxb->skb;
                rxb->skb = NULL;
        } else if (meta->callback)
                meta->callback(priv, cmd, rxb->skb);

        iwl_hcmd_queue_reclaim(priv, txq_id, index, cmd_index);

        if (!(meta->flags & CMD_ASYNC)) {
                clear_bit(STATUS_HCMD_ACTIVE, &priv->status);
                wake_up_interruptible(&priv->wait_command_queue);
        }
}
EXPORT_SYMBOL(iwl_tx_cmd_complete);

/*
 * Find first available (lowest unused) Tx Queue, mark it "active".
 * Called only when finding queue for aggregation.
 * Should never return anything < 7, because they should already
 * be in use as EDCA AC (0-3), Command (4), HCCA (5, 6).
 */
static int iwl_txq_ctx_activate_free(struct iwl_priv *priv)
{
        int txq_id;

        for (txq_id = 0; txq_id < priv->hw_params.max_txq_num; txq_id++)
                if (!test_and_set_bit(txq_id, &priv->txq_ctx_active_msk))
                        return txq_id;
        return -1;
}

int iwl_tx_agg_start(struct iwl_priv *priv, const u8 *ra, u16 tid, u16 *ssn)
{
        int sta_id;
        int tx_fifo;
        int txq_id;
        int ret;
        unsigned long flags;
        struct iwl_tid_data *tid_data;

        if (likely(tid < ARRAY_SIZE(default_tid_to_tx_fifo)))
                tx_fifo = default_tid_to_tx_fifo[tid];
        else
                return -EINVAL;

        IWL_WARN(priv, "%s on ra = %pM tid = %d\n",
                        __func__, ra, tid);

        sta_id = iwl_find_station(priv, ra);
        if (sta_id == IWL_INVALID_STATION) {
                IWL_ERR(priv, "Start AGG on invalid station\n");
                return -ENXIO;
        }
        if (unlikely(tid >= MAX_TID_COUNT))
                return -EINVAL;

        if (priv->stations[sta_id].tid[tid].agg.state != IWL_AGG_OFF) {
                IWL_ERR(priv, "Start AGG when state is not IWL_AGG_OFF !\n");
                return -ENXIO;
        }

        txq_id = iwl_txq_ctx_activate_free(priv);
        if (txq_id == -1) {
                IWL_ERR(priv, "No free aggregation queue available\n");
                return -ENXIO;
        }

        spin_lock_irqsave(&priv->sta_lock, flags);
        tid_data = &priv->stations[sta_id].tid[tid];
        *ssn = SEQ_TO_SN(tid_data->seq_number);
        tid_data->agg.txq_id = txq_id;
        priv->txq[txq_id].swq_id = iwl_virtual_agg_queue_num(tx_fifo, txq_id);
        spin_unlock_irqrestore(&priv->sta_lock, flags);

        ret = priv->cfg->ops->lib->txq_agg_enable(priv, txq_id, tx_fifo,
                                                  sta_id, tid, *ssn);
        if (ret)
                return ret;

        if (tid_data->tfds_in_queue == 0) {
                IWL_DEBUG_HT(priv, "HW queue is empty\n");
                tid_data->agg.state = IWL_AGG_ON;
                ieee80211_start_tx_ba_cb_irqsafe(priv->hw, ra, tid);
        } else {
                IWL_DEBUG_HT(priv, "HW queue is NOT empty: %d packets in HW queue\n",
                             tid_data->tfds_in_queue);
                tid_data->agg.state = IWL_EMPTYING_HW_QUEUE_ADDBA;
        }
        return ret;
}
EXPORT_SYMBOL(iwl_tx_agg_start);

int iwl_tx_agg_stop(struct iwl_priv *priv , const u8 *ra, u16 tid)
{
        int tx_fifo_id, txq_id, sta_id, ssn = -1;
        struct iwl_tid_data *tid_data;
        int ret, write_ptr, read_ptr;
        unsigned long flags;

        if (!ra) {
                IWL_ERR(priv, "ra = NULL\n");
                return -EINVAL;
        }

        if (unlikely(tid >= MAX_TID_COUNT))
                return -EINVAL;

        if (likely(tid < ARRAY_SIZE(default_tid_to_tx_fifo)))
                tx_fifo_id = default_tid_to_tx_fifo[tid];
        else
                return -EINVAL;

        sta_id = iwl_find_station(priv, ra);

        if (sta_id == IWL_INVALID_STATION) {
                IWL_ERR(priv, "Invalid station for AGG tid %d\n", tid);
                return -ENXIO;
        }

        if (priv->stations[sta_id].tid[tid].agg.state != IWL_AGG_ON)
                IWL_WARN(priv, "Stopping AGG while state not IWL_AGG_ON\n");

        tid_data = &priv->stations[sta_id].tid[tid];
        ssn = (tid_data->seq_number & IEEE80211_SCTL_SEQ) >> 4;
        txq_id = tid_data->agg.txq_id;
        write_ptr = priv->txq[txq_id].q.write_ptr;
        read_ptr = priv->txq[txq_id].q.read_ptr;

        /* The queue is not empty */
        if (write_ptr != read_ptr) {
                IWL_DEBUG_HT(priv, "Stopping a non empty AGG HW QUEUE\n");
                priv->stations[sta_id].tid[tid].agg.state =
                                IWL_EMPTYING_HW_QUEUE_DELBA;
                return 0;
        }

        IWL_DEBUG_HT(priv, "HW queue is empty\n");
        priv->stations[sta_id].tid[tid].agg.state = IWL_AGG_OFF;

        spin_lock_irqsave(&priv->lock, flags);
        ret = priv->cfg->ops->lib->txq_agg_disable(priv, txq_id, ssn,
                                                   tx_fifo_id);
        spin_unlock_irqrestore(&priv->lock, flags);

        if (ret)
                return ret;

        ieee80211_stop_tx_ba_cb_irqsafe(priv->hw, ra, tid);

        return 0;
}
EXPORT_SYMBOL(iwl_tx_agg_stop);

int iwl_txq_check_empty(struct iwl_priv *priv, int sta_id, u8 tid, int txq_id)
{
        struct iwl_queue *q = &priv->txq[txq_id].q;
        u8 *addr = priv->stations[sta_id].sta.sta.addr;
        struct iwl_tid_data *tid_data = &priv->stations[sta_id].tid[tid];

        switch (priv->stations[sta_id].tid[tid].agg.state) {
        case IWL_EMPTYING_HW_QUEUE_DELBA:
                /* We are reclaiming the last packet of the */
                /* aggregated HW queue */
                if ((txq_id  == tid_data->agg.txq_id) &&
                    (q->read_ptr == q->write_ptr)) {
                        u16 ssn = SEQ_TO_SN(tid_data->seq_number);
                        int tx_fifo = default_tid_to_tx_fifo[tid];
                        IWL_DEBUG_HT(priv, "HW queue empty: continue DELBA flow\n");
                        priv->cfg->ops->lib->txq_agg_disable(priv, txq_id,
                                                             ssn, tx_fifo);
                        tid_data->agg.state = IWL_AGG_OFF;
                        ieee80211_stop_tx_ba_cb_irqsafe(priv->hw, addr, tid);
                }
                break;
        case IWL_EMPTYING_HW_QUEUE_ADDBA:
                /* We are reclaiming the last packet of the queue */
                if (tid_data->tfds_in_queue == 0) {
                        IWL_DEBUG_HT(priv, "HW queue empty: continue ADDBA flow\n");
                        tid_data->agg.state = IWL_AGG_ON;
                        ieee80211_start_tx_ba_cb_irqsafe(priv->hw, addr, tid);
                }
                break;
        }
        return 0;
}
EXPORT_SYMBOL(iwl_txq_check_empty);

/**
 * iwl_tx_status_reply_compressed_ba - Update tx status from block-ack
 *
 * Go through block-ack's bitmap of ACK'd frames, update driver's record of
 * ACK vs. not.  This gets sent to mac80211, then to rate scaling algo.
 */
static int iwl_tx_status_reply_compressed_ba(struct iwl_priv *priv,
                                 struct iwl_ht_agg *agg,
                                 struct iwl_compressed_ba_resp *ba_resp)

{
        int i, sh, ack;
        u16 seq_ctl = le16_to_cpu(ba_resp->seq_ctl);
        u16 scd_flow = le16_to_cpu(ba_resp->scd_flow);
        u64 bitmap;
        int successes = 0;
        struct ieee80211_tx_info *info;

        if (unlikely(!agg->wait_for_ba))  {
                IWL_ERR(priv, "Received BA when not expected\n");
                return -EINVAL;
        }

        /* Mark that the expected block-ack response arrived */
        agg->wait_for_ba = 0;
        IWL_DEBUG_TX_REPLY(priv, "BA %d %d\n", agg->start_idx, ba_resp->seq_ctl);

        /* Calculate shift to align block-ack bits with our Tx window bits */
        sh = agg->start_idx - SEQ_TO_INDEX(seq_ctl >> 4);
        if (sh < 0) /* tbw something is wrong with indices */
                sh += 0x100;

        /* don't use 64-bit values for now */
        bitmap = le64_to_cpu(ba_resp->bitmap) >> sh;

        if (agg->frame_count > (64 - sh)) {
                IWL_DEBUG_TX_REPLY(priv, "more frames than bitmap size");
                return -1;
        }

        /* check for success or failure according to the
         * transmitted bitmap and block-ack bitmap */
        bitmap &= agg->bitmap;

        /* For each frame attempted in aggregation,
         * update driver's record of tx frame's status. */
        for (i = 0; i < agg->frame_count ; i++) {
                ack = bitmap & (1ULL << i);
                successes += !!ack;
                IWL_DEBUG_TX_REPLY(priv, "%s ON i=%d idx=%d raw=%d\n",
                        ack ? "ACK" : "NACK", i, (agg->start_idx + i) & 0xff,
                        agg->start_idx + i);
        }

        info = IEEE80211_SKB_CB(priv->txq[scd_flow].txb[agg->start_idx].skb[0]);
        memset(&info->status, 0, sizeof(info->status));
        info->flags = IEEE80211_TX_STAT_ACK;
        info->flags |= IEEE80211_TX_STAT_AMPDU;
        info->status.ampdu_ack_map = successes;
        info->status.ampdu_ack_len = agg->frame_count;
        iwl_hwrate_to_tx_control(priv, agg->rate_n_flags, info);

        IWL_DEBUG_TX_REPLY(priv, "Bitmap %llx\n", (unsigned long long)bitmap);

        return 0;
}

/**
 * iwl_rx_reply_compressed_ba - Handler for REPLY_COMPRESSED_BA
 *
 * Handles block-acknowledge notification from device, which reports success
 * of frames sent via aggregation.
 */
void iwl_rx_reply_compressed_ba(struct iwl_priv *priv,
                                           struct iwl_rx_mem_buffer *rxb)
{
        struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
        struct iwl_compressed_ba_resp *ba_resp = &pkt->u.compressed_ba;
        struct iwl_tx_queue *txq = NULL;
        struct iwl_ht_agg *agg;
        int index;
        int sta_id;
        int tid;

        /* "flow" corresponds to Tx queue */
        u16 scd_flow = le16_to_cpu(ba_resp->scd_flow);

        /* "ssn" is start of block-ack Tx window, corresponds to index
         * (in Tx queue's circular buffer) of first TFD/frame in window */
        u16 ba_resp_scd_ssn = le16_to_cpu(ba_resp->scd_ssn);

        if (scd_flow >= priv->hw_params.max_txq_num) {
                IWL_ERR(priv,
                        "BUG_ON scd_flow is bigger than number of queues\n");
                return;
        }

        txq = &priv->txq[scd_flow];
        sta_id = ba_resp->sta_id;
        tid = ba_resp->tid;
        agg = &priv->stations[sta_id].tid[tid].agg;

        /* Find index just before block-ack window */
        index = iwl_queue_dec_wrap(ba_resp_scd_ssn & 0xff, txq->q.n_bd);

        /* TODO: Need to get this copy more safely - now good for debug */

        IWL_DEBUG_TX_REPLY(priv, "REPLY_COMPRESSED_BA [%d] Received from %pM, "
                           "sta_id = %d\n",
                           agg->wait_for_ba,
                           (u8 *) &ba_resp->sta_addr_lo32,
                           ba_resp->sta_id);
        IWL_DEBUG_TX_REPLY(priv, "TID = %d, SeqCtl = %d, bitmap = 0x%llx, scd_flow = "
                           "%d, scd_ssn = %d\n",
                           ba_resp->tid,
                           ba_resp->seq_ctl,
                           (unsigned long long)le64_to_cpu(ba_resp->bitmap),
                           ba_resp->scd_flow,
                           ba_resp->scd_ssn);
        IWL_DEBUG_TX_REPLY(priv, "DAT start_idx = %d, bitmap = 0x%llx \n",
                           agg->start_idx,
                           (unsigned long long)agg->bitmap);

        /* Update driver's record of ACK vs. not for each frame in window */
        iwl_tx_status_reply_compressed_ba(priv, agg, ba_resp);

        /* Release all TFDs before the SSN, i.e. all TFDs in front of
         * block-ack window (we assume that they've been successfully
         * transmitted ... if not, it's too late anyway). */
        if (txq->q.read_ptr != (ba_resp_scd_ssn & 0xff)) {
                /* calculate mac80211 ampdu sw queue to wake */
                int freed = iwl_tx_queue_reclaim(priv, scd_flow, index);
                priv->stations[sta_id].tid[tid].tfds_in_queue -= freed;

                if ((iwl_queue_space(&txq->q) > txq->q.low_mark) &&
                    priv->mac80211_registered &&
                    (agg->state != IWL_EMPTYING_HW_QUEUE_DELBA))
                        iwl_wake_queue(priv, txq->swq_id);

                iwl_txq_check_empty(priv, sta_id, tid, scd_flow);
        }
}
EXPORT_SYMBOL(iwl_rx_reply_compressed_ba);

#ifdef CONFIG_IWLWIFI_DEBUG
#define TX_STATUS_ENTRY(x) case TX_STATUS_FAIL_ ## x: return #x

const char *iwl_get_tx_fail_reason(u32 status)
{
        switch (status & TX_STATUS_MSK) {
        case TX_STATUS_SUCCESS:
                return "SUCCESS";
                TX_STATUS_ENTRY(SHORT_LIMIT);
                TX_STATUS_ENTRY(LONG_LIMIT);
                TX_STATUS_ENTRY(FIFO_UNDERRUN);
                TX_STATUS_ENTRY(MGMNT_ABORT);
                TX_STATUS_ENTRY(NEXT_FRAG);
                TX_STATUS_ENTRY(LIFE_EXPIRE);
                TX_STATUS_ENTRY(DEST_PS);
                TX_STATUS_ENTRY(ABORTED);
                TX_STATUS_ENTRY(BT_RETRY);
                TX_STATUS_ENTRY(STA_INVALID);
                TX_STATUS_ENTRY(FRAG_DROPPED);
                TX_STATUS_ENTRY(TID_DISABLE);
                TX_STATUS_ENTRY(FRAME_FLUSHED);
                TX_STATUS_ENTRY(INSUFFICIENT_CF_POLL);
                TX_STATUS_ENTRY(TX_LOCKED);
                TX_STATUS_ENTRY(NO_BEACON_ON_RADAR);
        }

        return "UNKNOWN";
}
EXPORT_SYMBOL(iwl_get_tx_fail_reason);
#endif /* CONFIG_IWLWIFI_DEBUG */