Merge branch 'nvme-4.13' of git://git.infradead.org/nvme into for-linus

[mirror_ubuntu-artful-kernel.git] / drivers / net / wireless / intel / iwlwifi / pcie / tx.c

/******************************************************************************
 *
 * Copyright(c) 2003 - 2014 Intel Corporation. All rights reserved.
 * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
 * Copyright(c) 2016 - 2017 Intel Deutschland GmbH
 *
 * 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 <linuxwifi@intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 *****************************************************************************/
#include <linux/etherdevice.h>
#include <linux/ieee80211.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/pm_runtime.h>
#include <net/ip6_checksum.h>
#include <net/tso.h>

#include "iwl-debug.h"
#include "iwl-csr.h"
#include "iwl-prph.h"
#include "iwl-io.h"
#include "iwl-scd.h"
#include "iwl-op-mode.h"
#include "internal.h"
/* FIXME: need to abstract out TX command (once we know what it looks like) */
#include "dvm/commands.h"

#define IWL_TX_CRC_SIZE 4
#define IWL_TX_DELIMITER_SIZE 4

/*************** 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.
 *
 ***************************************************/

int iwl_queue_space(const struct iwl_txq *q)
{
        unsigned int max;
        unsigned int used;

        /*
         * To avoid ambiguity between empty and completely full queues, there
         * should always be less than TFD_QUEUE_SIZE_MAX elements in the queue.
         * If q->n_window is smaller than TFD_QUEUE_SIZE_MAX, there is no need
         * to reserve any queue entries for this purpose.
         */
        if (q->n_window < TFD_QUEUE_SIZE_MAX)
                max = q->n_window;
        else
                max = TFD_QUEUE_SIZE_MAX - 1;

        /*
         * TFD_QUEUE_SIZE_MAX is a power of 2, so the following is equivalent to
         * modulo by TFD_QUEUE_SIZE_MAX and is well defined.
         */
        used = (q->write_ptr - q->read_ptr) & (TFD_QUEUE_SIZE_MAX - 1);

        if (WARN_ON(used > max))
                return 0;

        return max - used;
}

/*
 * iwl_queue_init - Initialize queue's high/low-water and read/write indexes
 */
static int iwl_queue_init(struct iwl_txq *q, int slots_num)
{
        q->n_window = slots_num;

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

        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 = 0;
        q->read_ptr = 0;

        return 0;
}

int iwl_pcie_alloc_dma_ptr(struct iwl_trans *trans,
                           struct iwl_dma_ptr *ptr, size_t size)
{
        if (WARN_ON(ptr->addr))
                return -EINVAL;

        ptr->addr = dma_alloc_coherent(trans->dev, size,
                                       &ptr->dma, GFP_KERNEL);
        if (!ptr->addr)
                return -ENOMEM;
        ptr->size = size;
        return 0;
}

void iwl_pcie_free_dma_ptr(struct iwl_trans *trans, struct iwl_dma_ptr *ptr)
{
        if (unlikely(!ptr->addr))
                return;

        dma_free_coherent(trans->dev, ptr->size, ptr->addr, ptr->dma);
        memset(ptr, 0, sizeof(*ptr));
}

static void iwl_pcie_txq_stuck_timer(unsigned long data)
{
        struct iwl_txq *txq = (void *)data;
        struct iwl_trans_pcie *trans_pcie = txq->trans_pcie;
        struct iwl_trans *trans = iwl_trans_pcie_get_trans(trans_pcie);

        spin_lock(&txq->lock);
        /* check if triggered erroneously */
        if (txq->read_ptr == txq->write_ptr) {
                spin_unlock(&txq->lock);
                return;
        }
        spin_unlock(&txq->lock);

        iwl_trans_pcie_log_scd_error(trans, txq);

        iwl_force_nmi(trans);
}

/*
 * iwl_pcie_txq_update_byte_cnt_tbl - Set up entry in Tx byte-count array
 */
static void iwl_pcie_txq_update_byte_cnt_tbl(struct iwl_trans *trans,
                                             struct iwl_txq *txq, u16 byte_cnt,
                                             int num_tbs)
{
        struct iwlagn_scd_bc_tbl *scd_bc_tbl;
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int write_ptr = txq->write_ptr;
        int txq_id = txq->id;
        u8 sec_ctl = 0;
        u16 len = byte_cnt + IWL_TX_CRC_SIZE + IWL_TX_DELIMITER_SIZE;
        __le16 bc_ent;
        struct iwl_tx_cmd *tx_cmd =
                (void *)txq->entries[txq->write_ptr].cmd->payload;
        u8 sta_id = tx_cmd->sta_id;

        scd_bc_tbl = trans_pcie->scd_bc_tbls.addr;

        sec_ctl = tx_cmd->sec_ctl;

        switch (sec_ctl & TX_CMD_SEC_MSK) {
        case TX_CMD_SEC_CCM:
                len += IEEE80211_CCMP_MIC_LEN;
                break;
        case TX_CMD_SEC_TKIP:
                len += IEEE80211_TKIP_ICV_LEN;
                break;
        case TX_CMD_SEC_WEP:
                len += IEEE80211_WEP_IV_LEN + IEEE80211_WEP_ICV_LEN;
                break;
        }
        if (trans_pcie->bc_table_dword)
                len = DIV_ROUND_UP(len, 4);

        if (WARN_ON(len > 0xFFF || write_ptr >= TFD_QUEUE_SIZE_MAX))
                return;

        bc_ent = cpu_to_le16(len | (sta_id << 12));

        scd_bc_tbl[txq_id].tfd_offset[write_ptr] = bc_ent;

        if (write_ptr < TFD_QUEUE_SIZE_BC_DUP)
                scd_bc_tbl[txq_id].
                        tfd_offset[TFD_QUEUE_SIZE_MAX + write_ptr] = bc_ent;
}

static void iwl_pcie_txq_inval_byte_cnt_tbl(struct iwl_trans *trans,
                                            struct iwl_txq *txq)
{
        struct iwl_trans_pcie *trans_pcie =
                IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwlagn_scd_bc_tbl *scd_bc_tbl = trans_pcie->scd_bc_tbls.addr;
        int txq_id = txq->id;
        int read_ptr = txq->read_ptr;
        u8 sta_id = 0;
        __le16 bc_ent;
        struct iwl_tx_cmd *tx_cmd =
                (void *)txq->entries[read_ptr].cmd->payload;

        WARN_ON(read_ptr >= TFD_QUEUE_SIZE_MAX);

        if (txq_id != trans_pcie->cmd_queue)
                sta_id = tx_cmd->sta_id;

        bc_ent = cpu_to_le16(1 | (sta_id << 12));

        scd_bc_tbl[txq_id].tfd_offset[read_ptr] = bc_ent;

        if (read_ptr < TFD_QUEUE_SIZE_BC_DUP)
                scd_bc_tbl[txq_id].
                        tfd_offset[TFD_QUEUE_SIZE_MAX + read_ptr] = bc_ent;
}

/*
 * iwl_pcie_txq_inc_wr_ptr - Send new write index to hardware
 */
static void iwl_pcie_txq_inc_wr_ptr(struct iwl_trans *trans,
                                    struct iwl_txq *txq)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 reg = 0;
        int txq_id = txq->id;

        lockdep_assert_held(&txq->lock);

        /*
         * explicitly wake up the NIC if:
         * 1. shadow registers aren't enabled
         * 2. NIC is woken up for CMD regardless of shadow outside this function
         * 3. there is a chance that the NIC is asleep
         */
        if (!trans->cfg->base_params->shadow_reg_enable &&
            txq_id != trans_pcie->cmd_queue &&
            test_bit(STATUS_TPOWER_PMI, &trans->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(trans, CSR_UCODE_DRV_GP1);

                if (reg & CSR_UCODE_DRV_GP1_BIT_MAC_SLEEP) {
                        IWL_DEBUG_INFO(trans, "Tx queue %d requesting wakeup, GP1 = 0x%x\n",
                                       txq_id, reg);
                        iwl_set_bit(trans, CSR_GP_CNTRL,
                                    CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
                        txq->need_update = true;
                        return;
                }
        }

        /*
         * if not in power-save mode, uCode will never sleep when we're
         * trying to tx (during RFKILL, we're not trying to tx).
         */
        IWL_DEBUG_TX(trans, "Q:%d WR: 0x%x\n", txq_id, txq->write_ptr);
        if (!txq->block)
                iwl_write32(trans, HBUS_TARG_WRPTR,
                            txq->write_ptr | (txq_id << 8));
}

void iwl_pcie_txq_check_wrptrs(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int i;

        for (i = 0; i < trans->cfg->base_params->num_of_queues; i++) {
                struct iwl_txq *txq = trans_pcie->txq[i];

                if (!test_bit(i, trans_pcie->queue_used))
                        continue;

                spin_lock_bh(&txq->lock);
                if (txq->need_update) {
                        iwl_pcie_txq_inc_wr_ptr(trans, txq);
                        txq->need_update = false;
                }
                spin_unlock_bh(&txq->lock);
        }
}

static inline dma_addr_t iwl_pcie_tfd_tb_get_addr(struct iwl_trans *trans,
                                                  void *_tfd, u8 idx)
{

        if (trans->cfg->use_tfh) {
                struct iwl_tfh_tfd *tfd = _tfd;
                struct iwl_tfh_tb *tb = &tfd->tbs[idx];

                return (dma_addr_t)(le64_to_cpu(tb->addr));
        } else {
                struct iwl_tfd *tfd = _tfd;
                struct iwl_tfd_tb *tb = &tfd->tbs[idx];
                dma_addr_t addr = get_unaligned_le32(&tb->lo);
                dma_addr_t hi_len;

                if (sizeof(dma_addr_t) <= sizeof(u32))
                        return addr;

                hi_len = le16_to_cpu(tb->hi_n_len) & 0xF;

                /*
                 * shift by 16 twice to avoid warnings on 32-bit
                 * (where this code never runs anyway due to the
                 * if statement above)
                 */
                return addr | ((hi_len << 16) << 16);
        }
}

static inline void iwl_pcie_tfd_set_tb(struct iwl_trans *trans, void *tfd,
                                       u8 idx, dma_addr_t addr, u16 len)
{
        struct iwl_tfd *tfd_fh = (void *)tfd;
        struct iwl_tfd_tb *tb = &tfd_fh->tbs[idx];

        u16 hi_n_len = len << 4;

        put_unaligned_le32(addr, &tb->lo);
        hi_n_len |= iwl_get_dma_hi_addr(addr);

        tb->hi_n_len = cpu_to_le16(hi_n_len);

        tfd_fh->num_tbs = idx + 1;
}

static inline u8 iwl_pcie_tfd_get_num_tbs(struct iwl_trans *trans, void *_tfd)
{
        if (trans->cfg->use_tfh) {
                struct iwl_tfh_tfd *tfd = _tfd;

                return le16_to_cpu(tfd->num_tbs) & 0x1f;
        } else {
                struct iwl_tfd *tfd = _tfd;

                return tfd->num_tbs & 0x1f;
        }
}

static void iwl_pcie_tfd_unmap(struct iwl_trans *trans,
                               struct iwl_cmd_meta *meta,
                               struct iwl_txq *txq, int index)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int i, num_tbs;
        void *tfd = iwl_pcie_get_tfd(trans_pcie, txq, index);

        /* Sanity check on number of chunks */
        num_tbs = iwl_pcie_tfd_get_num_tbs(trans, tfd);

        if (num_tbs >= trans_pcie->max_tbs) {
                IWL_ERR(trans, "Too many chunks: %i\n", num_tbs);
                /* @todo issue fatal error, it is quite serious situation */
                return;
        }

        /* first TB is never freed - it's the bidirectional DMA data */

        for (i = 1; i < num_tbs; i++) {
                if (meta->tbs & BIT(i))
                        dma_unmap_page(trans->dev,
                                       iwl_pcie_tfd_tb_get_addr(trans, tfd, i),
                                       iwl_pcie_tfd_tb_get_len(trans, tfd, i),
                                       DMA_TO_DEVICE);
                else
                        dma_unmap_single(trans->dev,
                                         iwl_pcie_tfd_tb_get_addr(trans, tfd,
                                                                  i),
                                         iwl_pcie_tfd_tb_get_len(trans, tfd,
                                                                 i),
                                         DMA_TO_DEVICE);
        }

        if (trans->cfg->use_tfh) {
                struct iwl_tfh_tfd *tfd_fh = (void *)tfd;

                tfd_fh->num_tbs = 0;
        } else {
                struct iwl_tfd *tfd_fh = (void *)tfd;

                tfd_fh->num_tbs = 0;
        }

}

/*
 * iwl_pcie_txq_free_tfd - Free all chunks referenced by TFD [txq->q.read_ptr]
 * @trans - transport private data
 * @txq - tx queue
 * @dma_dir - the direction of the DMA mapping
 *
 * Does NOT advance any TFD circular buffer read/write indexes
 * Does NOT free the TFD itself (which is within circular buffer)
 */
void iwl_pcie_txq_free_tfd(struct iwl_trans *trans, struct iwl_txq *txq)
{
        /* rd_ptr is bounded by TFD_QUEUE_SIZE_MAX and
         * idx is bounded by n_window
         */
        int rd_ptr = txq->read_ptr;
        int idx = get_cmd_index(txq, rd_ptr);

        lockdep_assert_held(&txq->lock);

        /* We have only q->n_window txq->entries, but we use
         * TFD_QUEUE_SIZE_MAX tfds
         */
        iwl_pcie_tfd_unmap(trans, &txq->entries[idx].meta, txq, rd_ptr);

        /* free SKB */
        if (txq->entries) {
                struct sk_buff *skb;

                skb = txq->entries[idx].skb;

                /* Can be called from irqs-disabled context
                 * If skb is not NULL, it means that the whole queue is being
                 * freed and that the queue is not empty - free the skb
                 */
                if (skb) {
                        iwl_op_mode_free_skb(trans->op_mode, skb);
                        txq->entries[idx].skb = NULL;
                }
        }
}

static int iwl_pcie_txq_build_tfd(struct iwl_trans *trans, struct iwl_txq *txq,
                                  dma_addr_t addr, u16 len, bool reset)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        void *tfd;
        u32 num_tbs;

        tfd = txq->tfds + trans_pcie->tfd_size * txq->write_ptr;

        if (reset)
                memset(tfd, 0, trans_pcie->tfd_size);

        num_tbs = iwl_pcie_tfd_get_num_tbs(trans, tfd);

        /* Each TFD can point to a maximum max_tbs Tx buffers */
        if (num_tbs >= trans_pcie->max_tbs) {
                IWL_ERR(trans, "Error can not send more than %d chunks\n",
                        trans_pcie->max_tbs);
                return -EINVAL;
        }

        if (WARN(addr & ~IWL_TX_DMA_MASK,
                 "Unaligned address = %llx\n", (unsigned long long)addr))
                return -EINVAL;

        iwl_pcie_tfd_set_tb(trans, tfd, num_tbs, addr, len);

        return num_tbs;
}

int iwl_pcie_txq_alloc(struct iwl_trans *trans, struct iwl_txq *txq,
                       int slots_num, bool cmd_queue)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        size_t tfd_sz = trans_pcie->tfd_size * TFD_QUEUE_SIZE_MAX;
        size_t tb0_buf_sz;
        int i;

        if (WARN_ON(txq->entries || txq->tfds))
                return -EINVAL;

        setup_timer(&txq->stuck_timer, iwl_pcie_txq_stuck_timer,
                    (unsigned long)txq);
        txq->trans_pcie = trans_pcie;

        txq->n_window = slots_num;

        txq->entries = kcalloc(slots_num,
                               sizeof(struct iwl_pcie_txq_entry),
                               GFP_KERNEL);

        if (!txq->entries)
                goto error;

        if (cmd_queue)
                for (i = 0; i < slots_num; i++) {
                        txq->entries[i].cmd =
                                kmalloc(sizeof(struct iwl_device_cmd),
                                        GFP_KERNEL);
                        if (!txq->entries[i].cmd)
                                goto error;
                }

        /* Circular buffer of transmit frame descriptors (TFDs),
         * shared with device */
        txq->tfds = dma_alloc_coherent(trans->dev, tfd_sz,
                                       &txq->dma_addr, GFP_KERNEL);
        if (!txq->tfds)
                goto error;

        BUILD_BUG_ON(IWL_FIRST_TB_SIZE_ALIGN != sizeof(*txq->first_tb_bufs));

        tb0_buf_sz = sizeof(*txq->first_tb_bufs) * slots_num;

        txq->first_tb_bufs = dma_alloc_coherent(trans->dev, tb0_buf_sz,
                                              &txq->first_tb_dma,
                                              GFP_KERNEL);
        if (!txq->first_tb_bufs)
                goto err_free_tfds;

        return 0;
err_free_tfds:
        dma_free_coherent(trans->dev, tfd_sz, txq->tfds, txq->dma_addr);
error:
        if (txq->entries && cmd_queue)
                for (i = 0; i < slots_num; i++)
                        kfree(txq->entries[i].cmd);
        kfree(txq->entries);
        txq->entries = NULL;

        return -ENOMEM;

}

int iwl_pcie_txq_init(struct iwl_trans *trans, struct iwl_txq *txq,
                      int slots_num, bool cmd_queue)
{
        int ret;

        txq->need_update = false;

        /* 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 */
        ret = iwl_queue_init(txq, slots_num);
        if (ret)
                return ret;

        spin_lock_init(&txq->lock);

        if (cmd_queue) {
                static struct lock_class_key iwl_pcie_cmd_queue_lock_class;

                lockdep_set_class(&txq->lock, &iwl_pcie_cmd_queue_lock_class);
        }

        __skb_queue_head_init(&txq->overflow_q);

        return 0;
}

static void iwl_pcie_free_tso_page(struct iwl_trans_pcie *trans_pcie,
                                   struct sk_buff *skb)
{
        struct page **page_ptr;

        page_ptr = (void *)((u8 *)skb->cb + trans_pcie->page_offs);

        if (*page_ptr) {
                __free_page(*page_ptr);
                *page_ptr = NULL;
        }
}

static void iwl_pcie_clear_cmd_in_flight(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

        lockdep_assert_held(&trans_pcie->reg_lock);

        if (trans_pcie->ref_cmd_in_flight) {
                trans_pcie->ref_cmd_in_flight = false;
                IWL_DEBUG_RPM(trans, "clear ref_cmd_in_flight - unref\n");
                iwl_trans_unref(trans);
        }

        if (!trans->cfg->base_params->apmg_wake_up_wa)
                return;
        if (WARN_ON(!trans_pcie->cmd_hold_nic_awake))
                return;

        trans_pcie->cmd_hold_nic_awake = false;
        __iwl_trans_pcie_clear_bit(trans, CSR_GP_CNTRL,
                                   CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
}

/*
 * iwl_pcie_txq_unmap -  Unmap any remaining DMA mappings and free skb's
 */
static void iwl_pcie_txq_unmap(struct iwl_trans *trans, int txq_id)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[txq_id];

        spin_lock_bh(&txq->lock);
        while (txq->write_ptr != txq->read_ptr) {
                IWL_DEBUG_TX_REPLY(trans, "Q %d Free %d\n",
                                   txq_id, txq->read_ptr);

                if (txq_id != trans_pcie->cmd_queue) {
                        struct sk_buff *skb = txq->entries[txq->read_ptr].skb;

                        if (WARN_ON_ONCE(!skb))
                                continue;

                        iwl_pcie_free_tso_page(trans_pcie, skb);
                }
                iwl_pcie_txq_free_tfd(trans, txq);
                txq->read_ptr = iwl_queue_inc_wrap(txq->read_ptr);

                if (txq->read_ptr == txq->write_ptr) {
                        unsigned long flags;

                        spin_lock_irqsave(&trans_pcie->reg_lock, flags);
                        if (txq_id != trans_pcie->cmd_queue) {
                                IWL_DEBUG_RPM(trans, "Q %d - last tx freed\n",
                                              txq->id);
                                iwl_trans_unref(trans);
                        } else {
                                iwl_pcie_clear_cmd_in_flight(trans);
                        }
                        spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
                }
        }

        while (!skb_queue_empty(&txq->overflow_q)) {
                struct sk_buff *skb = __skb_dequeue(&txq->overflow_q);

                iwl_op_mode_free_skb(trans->op_mode, skb);
        }

        spin_unlock_bh(&txq->lock);

        /* just in case - this queue may have been stopped */
        iwl_wake_queue(trans, txq);
}

/*
 * iwl_pcie_txq_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.
 */
static void iwl_pcie_txq_free(struct iwl_trans *trans, int txq_id)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[txq_id];
        struct device *dev = trans->dev;
        int i;

        if (WARN_ON(!txq))
                return;

        iwl_pcie_txq_unmap(trans, txq_id);

        /* De-alloc array of command/tx buffers */
        if (txq_id == trans_pcie->cmd_queue)
                for (i = 0; i < txq->n_window; i++) {
                        kzfree(txq->entries[i].cmd);
                        kzfree(txq->entries[i].free_buf);
                }

        /* De-alloc circular buffer of TFDs */
        if (txq->tfds) {
                dma_free_coherent(dev,
                                  trans_pcie->tfd_size * TFD_QUEUE_SIZE_MAX,
                                  txq->tfds, txq->dma_addr);
                txq->dma_addr = 0;
                txq->tfds = NULL;

                dma_free_coherent(dev,
                                  sizeof(*txq->first_tb_bufs) * txq->n_window,
                                  txq->first_tb_bufs, txq->first_tb_dma);
        }

        kfree(txq->entries);
        txq->entries = NULL;

        del_timer_sync(&txq->stuck_timer);

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

void iwl_pcie_tx_start(struct iwl_trans *trans, u32 scd_base_addr)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int nq = trans->cfg->base_params->num_of_queues;
        int chan;
        u32 reg_val;
        int clear_dwords = (SCD_TRANS_TBL_OFFSET_QUEUE(nq) -
                                SCD_CONTEXT_MEM_LOWER_BOUND) / sizeof(u32);

        /* make sure all queue are not stopped/used */
        memset(trans_pcie->queue_stopped, 0, sizeof(trans_pcie->queue_stopped));
        memset(trans_pcie->queue_used, 0, sizeof(trans_pcie->queue_used));

        trans_pcie->scd_base_addr =
                iwl_read_prph(trans, SCD_SRAM_BASE_ADDR);

        WARN_ON(scd_base_addr != 0 &&
                scd_base_addr != trans_pcie->scd_base_addr);

        /* reset context data, TX status and translation data */
        iwl_trans_write_mem(trans, trans_pcie->scd_base_addr +
                                   SCD_CONTEXT_MEM_LOWER_BOUND,
                            NULL, clear_dwords);

        iwl_write_prph(trans, SCD_DRAM_BASE_ADDR,
                       trans_pcie->scd_bc_tbls.dma >> 10);

        /* The chain extension of the SCD doesn't work well. This feature is
         * enabled by default by the HW, so we need to disable it manually.
         */
        if (trans->cfg->base_params->scd_chain_ext_wa)
                iwl_write_prph(trans, SCD_CHAINEXT_EN, 0);

        iwl_trans_ac_txq_enable(trans, trans_pcie->cmd_queue,
                                trans_pcie->cmd_fifo,
                                trans_pcie->cmd_q_wdg_timeout);

        /* Activate all Tx DMA/FIFO channels */
        iwl_scd_activate_fifos(trans);

        /* Enable DMA channel */
        for (chan = 0; chan < FH_TCSR_CHNL_NUM; chan++)
                iwl_write_direct32(trans, FH_TCSR_CHNL_TX_CONFIG_REG(chan),
                                   FH_TCSR_TX_CONFIG_REG_VAL_DMA_CHNL_ENABLE |
                                   FH_TCSR_TX_CONFIG_REG_VAL_DMA_CREDIT_ENABLE);

        /* Update FH chicken bits */
        reg_val = iwl_read_direct32(trans, FH_TX_CHICKEN_BITS_REG);
        iwl_write_direct32(trans, FH_TX_CHICKEN_BITS_REG,
                           reg_val | FH_TX_CHICKEN_BITS_SCD_AUTO_RETRY_EN);

        /* Enable L1-Active */
        if (trans->cfg->device_family < IWL_DEVICE_FAMILY_8000)
                iwl_clear_bits_prph(trans, APMG_PCIDEV_STT_REG,
                                    APMG_PCIDEV_STT_VAL_L1_ACT_DIS);
}

void iwl_trans_pcie_tx_reset(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int txq_id;

        /*
         * we should never get here in gen2 trans mode return early to avoid
         * having invalid accesses
         */
        if (WARN_ON_ONCE(trans->cfg->gen2))
                return;

        for (txq_id = 0; txq_id < trans->cfg->base_params->num_of_queues;
             txq_id++) {
                struct iwl_txq *txq = trans_pcie->txq[txq_id];
                if (trans->cfg->use_tfh)
                        iwl_write_direct64(trans,
                                           FH_MEM_CBBC_QUEUE(trans, txq_id),
                                           txq->dma_addr);
                else
                        iwl_write_direct32(trans,
                                           FH_MEM_CBBC_QUEUE(trans, txq_id),
                                           txq->dma_addr >> 8);
                iwl_pcie_txq_unmap(trans, txq_id);
                txq->read_ptr = 0;
                txq->write_ptr = 0;
        }

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

        /*
         * Send 0 as the scd_base_addr since the device may have be reset
         * while we were in WoWLAN in which case SCD_SRAM_BASE_ADDR will
         * contain garbage.
         */
        iwl_pcie_tx_start(trans, 0);
}

static void iwl_pcie_tx_stop_fh(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        unsigned long flags;
        int ch, ret;
        u32 mask = 0;

        spin_lock(&trans_pcie->irq_lock);

        if (!iwl_trans_grab_nic_access(trans, &flags))
                goto out;

        /* Stop each Tx DMA channel */
        for (ch = 0; ch < FH_TCSR_CHNL_NUM; ch++) {
                iwl_write32(trans, FH_TCSR_CHNL_TX_CONFIG_REG(ch), 0x0);
                mask |= FH_TSSR_TX_STATUS_REG_MSK_CHNL_IDLE(ch);
        }

        /* Wait for DMA channels to be idle */
        ret = iwl_poll_bit(trans, FH_TSSR_TX_STATUS_REG, mask, mask, 5000);
        if (ret < 0)
                IWL_ERR(trans,
                        "Failing on timeout while stopping DMA channel %d [0x%08x]\n",
                        ch, iwl_read32(trans, FH_TSSR_TX_STATUS_REG));

        iwl_trans_release_nic_access(trans, &flags);

out:
        spin_unlock(&trans_pcie->irq_lock);
}

/*
 * iwl_pcie_tx_stop - Stop all Tx DMA channels
 */
int iwl_pcie_tx_stop(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int txq_id;

        /* Turn off all Tx DMA fifos */
        iwl_scd_deactivate_fifos(trans);

        /* Turn off all Tx DMA channels */
        iwl_pcie_tx_stop_fh(trans);

        /*
         * This function can be called before the op_mode disabled the
         * queues. This happens when we have an rfkill interrupt.
         * Since we stop Tx altogether - mark the queues as stopped.
         */
        memset(trans_pcie->queue_stopped, 0, sizeof(trans_pcie->queue_stopped));
        memset(trans_pcie->queue_used, 0, sizeof(trans_pcie->queue_used));

        /* This can happen: start_hw, stop_device */
        if (!trans_pcie->txq_memory)
                return 0;

        /* Unmap DMA from host system and free skb's */
        for (txq_id = 0; txq_id < trans->cfg->base_params->num_of_queues;
             txq_id++)
                iwl_pcie_txq_unmap(trans, txq_id);

        return 0;
}

/*
 * iwl_trans_tx_free - Free TXQ Context
 *
 * Destroy all TX DMA queues and structures
 */
void iwl_pcie_tx_free(struct iwl_trans *trans)
{
        int txq_id;
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

        memset(trans_pcie->queue_used, 0, sizeof(trans_pcie->queue_used));

        /* Tx queues */
        if (trans_pcie->txq_memory) {
                for (txq_id = 0;
                     txq_id < trans->cfg->base_params->num_of_queues;
                     txq_id++) {
                        iwl_pcie_txq_free(trans, txq_id);
                        trans_pcie->txq[txq_id] = NULL;
                }
        }

        kfree(trans_pcie->txq_memory);
        trans_pcie->txq_memory = NULL;

        iwl_pcie_free_dma_ptr(trans, &trans_pcie->kw);

        iwl_pcie_free_dma_ptr(trans, &trans_pcie->scd_bc_tbls);
}

/*
 * iwl_pcie_tx_alloc - allocate TX context
 * Allocate all Tx DMA structures and initialize them
 */
static int iwl_pcie_tx_alloc(struct iwl_trans *trans)
{
        int ret;
        int txq_id, slots_num;
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

        u16 scd_bc_tbls_size = trans->cfg->base_params->num_of_queues *
                        sizeof(struct iwlagn_scd_bc_tbl);

        /*It is not allowed to alloc twice, so warn when this happens.
         * We cannot rely on the previous allocation, so free and fail */
        if (WARN_ON(trans_pcie->txq_memory)) {
                ret = -EINVAL;
                goto error;
        }

        ret = iwl_pcie_alloc_dma_ptr(trans, &trans_pcie->scd_bc_tbls,
                                   scd_bc_tbls_size);
        if (ret) {
                IWL_ERR(trans, "Scheduler BC Table allocation failed\n");
                goto error;
        }

        /* Alloc keep-warm buffer */
        ret = iwl_pcie_alloc_dma_ptr(trans, &trans_pcie->kw, IWL_KW_SIZE);
        if (ret) {
                IWL_ERR(trans, "Keep Warm allocation failed\n");
                goto error;
        }

        trans_pcie->txq_memory = kcalloc(trans->cfg->base_params->num_of_queues,
                                         sizeof(struct iwl_txq), GFP_KERNEL);
        if (!trans_pcie->txq_memory) {
                IWL_ERR(trans, "Not enough memory for txq\n");
                ret = -ENOMEM;
                goto error;
        }

        /* Alloc and init all Tx queues, including the command queue (#4/#9) */
        for (txq_id = 0; txq_id < trans->cfg->base_params->num_of_queues;
             txq_id++) {
                bool cmd_queue = (txq_id == trans_pcie->cmd_queue);

                slots_num = cmd_queue ? TFD_CMD_SLOTS : TFD_TX_CMD_SLOTS;
                trans_pcie->txq[txq_id] = &trans_pcie->txq_memory[txq_id];
                ret = iwl_pcie_txq_alloc(trans, trans_pcie->txq[txq_id],
                                         slots_num, cmd_queue);
                if (ret) {
                        IWL_ERR(trans, "Tx %d queue alloc failed\n", txq_id);
                        goto error;
                }
                trans_pcie->txq[txq_id]->id = txq_id;
        }

        return 0;

error:
        iwl_pcie_tx_free(trans);

        return ret;
}

int iwl_pcie_tx_init(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int ret;
        int txq_id, slots_num;
        bool alloc = false;

        if (!trans_pcie->txq_memory) {
                ret = iwl_pcie_tx_alloc(trans);
                if (ret)
                        goto error;
                alloc = true;
        }

        spin_lock(&trans_pcie->irq_lock);

        /* Turn off all Tx DMA fifos */
        iwl_scd_deactivate_fifos(trans);

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

        spin_unlock(&trans_pcie->irq_lock);

        /* Alloc and init all Tx queues, including the command queue (#4/#9) */
        for (txq_id = 0; txq_id < trans->cfg->base_params->num_of_queues;
             txq_id++) {
                bool cmd_queue = (txq_id == trans_pcie->cmd_queue);

                slots_num = cmd_queue ? TFD_CMD_SLOTS : TFD_TX_CMD_SLOTS;
                ret = iwl_pcie_txq_init(trans, trans_pcie->txq[txq_id],
                                        slots_num, cmd_queue);
                if (ret) {
                        IWL_ERR(trans, "Tx %d queue init failed\n", txq_id);
                        goto error;
                }

                /*
                 * Tell nic where to find circular buffer of TFDs for a
                 * given Tx queue, and enable the DMA channel used for that
                 * queue.
                 * Circular buffer (TFD queue in DRAM) physical base address
                 */
                iwl_write_direct32(trans, FH_MEM_CBBC_QUEUE(trans, txq_id),
                                   trans_pcie->txq[txq_id]->dma_addr >> 8);
        }

        iwl_set_bits_prph(trans, SCD_GP_CTRL, SCD_GP_CTRL_AUTO_ACTIVE_MODE);
        if (trans->cfg->base_params->num_of_queues > 20)
                iwl_set_bits_prph(trans, SCD_GP_CTRL,
                                  SCD_GP_CTRL_ENABLE_31_QUEUES);

        return 0;
error:
        /*Upon error, free only if we allocated something */
        if (alloc)
                iwl_pcie_tx_free(trans);
        return ret;
}

static inline void iwl_pcie_txq_progress(struct iwl_txq *txq)
{
        lockdep_assert_held(&txq->lock);

        if (!txq->wd_timeout)
                return;

        /*
         * station is asleep and we send data - that must
         * be uAPSD or PS-Poll. Don't rearm the timer.
         */
        if (txq->frozen)
                return;

        /*
         * if empty delete timer, otherwise move timer forward
         * since we're making progress on this queue
         */
        if (txq->read_ptr == txq->write_ptr)
                del_timer(&txq->stuck_timer);
        else
                mod_timer(&txq->stuck_timer, jiffies + txq->wd_timeout);
}

/* Frees buffers until index _not_ inclusive */
void iwl_trans_pcie_reclaim(struct iwl_trans *trans, int txq_id, int ssn,
                            struct sk_buff_head *skbs)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[txq_id];
        int tfd_num = ssn & (TFD_QUEUE_SIZE_MAX - 1);
        int last_to_free;

        /* This function is not meant to release cmd queue*/
        if (WARN_ON(txq_id == trans_pcie->cmd_queue))
                return;

        spin_lock_bh(&txq->lock);

        if (!test_bit(txq_id, trans_pcie->queue_used)) {
                IWL_DEBUG_TX_QUEUES(trans, "Q %d inactive - ignoring idx %d\n",
                                    txq_id, ssn);
                goto out;
        }

        if (txq->read_ptr == tfd_num)
                goto out;

        IWL_DEBUG_TX_REPLY(trans, "[Q %d] %d -> %d (%d)\n",
                           txq_id, txq->read_ptr, tfd_num, ssn);

        /*Since we free until index _not_ inclusive, the one before index is
         * the last we will free. This one must be used */
        last_to_free = iwl_queue_dec_wrap(tfd_num);

        if (!iwl_queue_used(txq, last_to_free)) {
                IWL_ERR(trans,
                        "%s: Read index for DMA queue txq id (%d), last_to_free %d is out of range [0-%d] %d %d.\n",
                        __func__, txq_id, last_to_free, TFD_QUEUE_SIZE_MAX,
                        txq->write_ptr, txq->read_ptr);
                goto out;
        }

        if (WARN_ON(!skb_queue_empty(skbs)))
                goto out;

        for (;
             txq->read_ptr != tfd_num;
             txq->read_ptr = iwl_queue_inc_wrap(txq->read_ptr)) {
                struct sk_buff *skb = txq->entries[txq->read_ptr].skb;

                if (WARN_ON_ONCE(!skb))
                        continue;

                iwl_pcie_free_tso_page(trans_pcie, skb);

                __skb_queue_tail(skbs, skb);

                txq->entries[txq->read_ptr].skb = NULL;

                if (!trans->cfg->use_tfh)
                        iwl_pcie_txq_inval_byte_cnt_tbl(trans, txq);

                iwl_pcie_txq_free_tfd(trans, txq);
        }

        iwl_pcie_txq_progress(txq);

        if (iwl_queue_space(txq) > txq->low_mark &&
            test_bit(txq_id, trans_pcie->queue_stopped)) {
                struct sk_buff_head overflow_skbs;

                __skb_queue_head_init(&overflow_skbs);
                skb_queue_splice_init(&txq->overflow_q, &overflow_skbs);

                /*
                 * This is tricky: we are in reclaim path which is non
                 * re-entrant, so noone will try to take the access the
                 * txq data from that path. We stopped tx, so we can't
                 * have tx as well. Bottom line, we can unlock and re-lock
                 * later.
                 */
                spin_unlock_bh(&txq->lock);

                while (!skb_queue_empty(&overflow_skbs)) {
                        struct sk_buff *skb = __skb_dequeue(&overflow_skbs);
                        struct iwl_device_cmd *dev_cmd_ptr;

                        dev_cmd_ptr = *(void **)((u8 *)skb->cb +
                                                 trans_pcie->dev_cmd_offs);

                        /*
                         * Note that we can very well be overflowing again.
                         * In that case, iwl_queue_space will be small again
                         * and we won't wake mac80211's queue.
                         */
                        iwl_trans_pcie_tx(trans, skb, dev_cmd_ptr, txq_id);
                }
                spin_lock_bh(&txq->lock);

                if (iwl_queue_space(txq) > txq->low_mark)
                        iwl_wake_queue(trans, txq);
        }

        if (txq->read_ptr == txq->write_ptr) {
                IWL_DEBUG_RPM(trans, "Q %d - last tx reclaimed\n", txq->id);
                iwl_trans_unref(trans);
        }

out:
        spin_unlock_bh(&txq->lock);
}

static int iwl_pcie_set_cmd_in_flight(struct iwl_trans *trans,
                                      const struct iwl_host_cmd *cmd)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int ret;

        lockdep_assert_held(&trans_pcie->reg_lock);

        if (!(cmd->flags & CMD_SEND_IN_IDLE) &&
            !trans_pcie->ref_cmd_in_flight) {
                trans_pcie->ref_cmd_in_flight = true;
                IWL_DEBUG_RPM(trans, "set ref_cmd_in_flight - ref\n");
                iwl_trans_ref(trans);
        }

        /*
         * wake up the NIC to make sure that the firmware will see the host
         * command - we will let the NIC sleep once all the host commands
         * returned. This needs to be done only on NICs that have
         * apmg_wake_up_wa set.
         */
        if (trans->cfg->base_params->apmg_wake_up_wa &&
            !trans_pcie->cmd_hold_nic_awake) {
                __iwl_trans_pcie_set_bit(trans, CSR_GP_CNTRL,
                                         CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);

                ret = iwl_poll_bit(trans, CSR_GP_CNTRL,
                                   CSR_GP_CNTRL_REG_VAL_MAC_ACCESS_EN,
                                   (CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY |
                                    CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP),
                                   15000);
                if (ret < 0) {
                        __iwl_trans_pcie_clear_bit(trans, CSR_GP_CNTRL,
                                        CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
                        IWL_ERR(trans, "Failed to wake NIC for hcmd\n");
                        return -EIO;
                }
                trans_pcie->cmd_hold_nic_awake = true;
        }

        return 0;
}

/*
 * iwl_pcie_cmdq_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_pcie_cmdq_reclaim(struct iwl_trans *trans, int txq_id, int idx)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[txq_id];
        unsigned long flags;
        int nfreed = 0;

        lockdep_assert_held(&txq->lock);

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

        for (idx = iwl_queue_inc_wrap(idx); txq->read_ptr != idx;
             txq->read_ptr = iwl_queue_inc_wrap(txq->read_ptr)) {

                if (nfreed++ > 0) {
                        IWL_ERR(trans, "HCMD skipped: index (%d) %d %d\n",
                                idx, txq->write_ptr, txq->read_ptr);
                        iwl_force_nmi(trans);
                }
        }

        if (txq->read_ptr == txq->write_ptr) {
                spin_lock_irqsave(&trans_pcie->reg_lock, flags);
                iwl_pcie_clear_cmd_in_flight(trans);
                spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
        }

        iwl_pcie_txq_progress(txq);
}

static int iwl_pcie_txq_set_ratid_map(struct iwl_trans *trans, u16 ra_tid,
                                 u16 txq_id)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 tbl_dw_addr;
        u32 tbl_dw;
        u16 scd_q2ratid;

        scd_q2ratid = ra_tid & SCD_QUEUE_RA_TID_MAP_RATID_MSK;

        tbl_dw_addr = trans_pcie->scd_base_addr +
                        SCD_TRANS_TBL_OFFSET_QUEUE(txq_id);

        tbl_dw = iwl_trans_read_mem32(trans, tbl_dw_addr);

        if (txq_id & 0x1)
                tbl_dw = (scd_q2ratid << 16) | (tbl_dw & 0x0000FFFF);
        else
                tbl_dw = scd_q2ratid | (tbl_dw & 0xFFFF0000);

        iwl_trans_write_mem32(trans, tbl_dw_addr, tbl_dw);

        return 0;
}

/* Receiver address (actually, Rx station's index into station table),
 * combined with Traffic ID (QOS priority), in format used by Tx Scheduler */
#define BUILD_RAxTID(sta_id, tid)       (((sta_id) << 4) + (tid))

bool iwl_trans_pcie_txq_enable(struct iwl_trans *trans, int txq_id, u16 ssn,
                               const struct iwl_trans_txq_scd_cfg *cfg,
                               unsigned int wdg_timeout)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[txq_id];
        int fifo = -1;
        bool scd_bug = false;

        if (test_and_set_bit(txq_id, trans_pcie->queue_used))
                WARN_ONCE(1, "queue %d already used - expect issues", txq_id);

        txq->wd_timeout = msecs_to_jiffies(wdg_timeout);

        if (cfg) {
                fifo = cfg->fifo;

                /* Disable the scheduler prior configuring the cmd queue */
                if (txq_id == trans_pcie->cmd_queue &&
                    trans_pcie->scd_set_active)
                        iwl_scd_enable_set_active(trans, 0);

                /* Stop this Tx queue before configuring it */
                iwl_scd_txq_set_inactive(trans, txq_id);

                /* Set this queue as a chain-building queue unless it is CMD */
                if (txq_id != trans_pcie->cmd_queue)
                        iwl_scd_txq_set_chain(trans, txq_id);

                if (cfg->aggregate) {
                        u16 ra_tid = BUILD_RAxTID(cfg->sta_id, cfg->tid);

                        /* Map receiver-address / traffic-ID to this queue */
                        iwl_pcie_txq_set_ratid_map(trans, ra_tid, txq_id);

                        /* enable aggregations for the queue */
                        iwl_scd_txq_enable_agg(trans, txq_id);
                        txq->ampdu = true;
                } else {
                        /*
                         * disable aggregations for the queue, this will also
                         * make the ra_tid mapping configuration irrelevant
                         * since it is now a non-AGG queue.
                         */
                        iwl_scd_txq_disable_agg(trans, txq_id);

                        ssn = txq->read_ptr;
                }
        } else {
                /*
                 * If we need to move the SCD write pointer by steps of
                 * 0x40, 0x80 or 0xc0, it gets stuck. Avoids this and let
                 * the op_mode know by returning true later.
                 * Do this only in case cfg is NULL since this trick can
                 * be done only if we have DQA enabled which is true for mvm
                 * only. And mvm never sets a cfg pointer.
                 * This is really ugly, but this is the easiest way out for
                 * this sad hardware issue.
                 * This bug has been fixed on devices 9000 and up.
                 */
                scd_bug = !trans->cfg->mq_rx_supported &&
                        !((ssn - txq->write_ptr) & 0x3f) &&
                        (ssn != txq->write_ptr);
                if (scd_bug)
                        ssn++;
        }

        /* Place first TFD at index corresponding to start sequence number.
         * Assumes that ssn_idx is valid (!= 0xFFF) */
        txq->read_ptr = (ssn & 0xff);
        txq->write_ptr = (ssn & 0xff);
        iwl_write_direct32(trans, HBUS_TARG_WRPTR,
                           (ssn & 0xff) | (txq_id << 8));

        if (cfg) {
                u8 frame_limit = cfg->frame_limit;

                iwl_write_prph(trans, SCD_QUEUE_RDPTR(txq_id), ssn);

                /* Set up Tx window size and frame limit for this queue */
                iwl_trans_write_mem32(trans, trans_pcie->scd_base_addr +
                                SCD_CONTEXT_QUEUE_OFFSET(txq_id), 0);
                iwl_trans_write_mem32(trans,
                        trans_pcie->scd_base_addr +
                        SCD_CONTEXT_QUEUE_OFFSET(txq_id) + sizeof(u32),
                        SCD_QUEUE_CTX_REG2_VAL(WIN_SIZE, frame_limit) |
                        SCD_QUEUE_CTX_REG2_VAL(FRAME_LIMIT, frame_limit));

                /* Set up status area in SRAM, map to Tx DMA/FIFO, activate */
                iwl_write_prph(trans, SCD_QUEUE_STATUS_BITS(txq_id),
                               (1 << SCD_QUEUE_STTS_REG_POS_ACTIVE) |
                               (cfg->fifo << SCD_QUEUE_STTS_REG_POS_TXF) |
                               (1 << SCD_QUEUE_STTS_REG_POS_WSL) |
                               SCD_QUEUE_STTS_REG_MSK);

                /* enable the scheduler for this queue (only) */
                if (txq_id == trans_pcie->cmd_queue &&
                    trans_pcie->scd_set_active)
                        iwl_scd_enable_set_active(trans, BIT(txq_id));

                IWL_DEBUG_TX_QUEUES(trans,
                                    "Activate queue %d on FIFO %d WrPtr: %d\n",
                                    txq_id, fifo, ssn & 0xff);
        } else {
                IWL_DEBUG_TX_QUEUES(trans,
                                    "Activate queue %d WrPtr: %d\n",
                                    txq_id, ssn & 0xff);
        }

        return scd_bug;
}

void iwl_trans_pcie_txq_set_shared_mode(struct iwl_trans *trans, u32 txq_id,
                                        bool shared_mode)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[txq_id];

        txq->ampdu = !shared_mode;
}

void iwl_trans_pcie_txq_disable(struct iwl_trans *trans, int txq_id,
                                bool configure_scd)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 stts_addr = trans_pcie->scd_base_addr +
                        SCD_TX_STTS_QUEUE_OFFSET(txq_id);
        static const u32 zero_val[4] = {};

        trans_pcie->txq[txq_id]->frozen_expiry_remainder = 0;
        trans_pcie->txq[txq_id]->frozen = false;

        /*
         * Upon HW Rfkill - we stop the device, and then stop the queues
         * in the op_mode. Just for the sake of the simplicity of the op_mode,
         * allow the op_mode to call txq_disable after it already called
         * stop_device.
         */
        if (!test_and_clear_bit(txq_id, trans_pcie->queue_used)) {
                WARN_ONCE(test_bit(STATUS_DEVICE_ENABLED, &trans->status),
                          "queue %d not used", txq_id);
                return;
        }

        if (configure_scd) {
                iwl_scd_txq_set_inactive(trans, txq_id);

                iwl_trans_write_mem(trans, stts_addr, (void *)zero_val,
                                    ARRAY_SIZE(zero_val));
        }

        iwl_pcie_txq_unmap(trans, txq_id);
        trans_pcie->txq[txq_id]->ampdu = false;

        IWL_DEBUG_TX_QUEUES(trans, "Deactivate queue %d\n", txq_id);
}

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

/*
 * iwl_pcie_enqueue_hcmd - enqueue a uCode command
 * @priv: device private data point
 * @cmd: a pointer to the ucode command structure
 *
 * The function returns < 0 values to indicate the operation
 * failed. On success, it returns the index (>= 0) of command in the
 * command queue.
 */
static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
                                 struct iwl_host_cmd *cmd)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[trans_pcie->cmd_queue];
        struct iwl_device_cmd *out_cmd;
        struct iwl_cmd_meta *out_meta;
        unsigned long flags;
        void *dup_buf = NULL;
        dma_addr_t phys_addr;
        int idx;
        u16 copy_size, cmd_size, tb0_size;
        bool had_nocopy = false;
        u8 group_id = iwl_cmd_groupid(cmd->id);
        int i, ret;
        u32 cmd_pos;
        const u8 *cmddata[IWL_MAX_CMD_TBS_PER_TFD];
        u16 cmdlen[IWL_MAX_CMD_TBS_PER_TFD];

        if (WARN(!trans->wide_cmd_header &&
                 group_id > IWL_ALWAYS_LONG_GROUP,
                 "unsupported wide command %#x\n", cmd->id))
                return -EINVAL;

        if (group_id != 0) {
                copy_size = sizeof(struct iwl_cmd_header_wide);
                cmd_size = sizeof(struct iwl_cmd_header_wide);
        } else {
                copy_size = sizeof(struct iwl_cmd_header);
                cmd_size = sizeof(struct iwl_cmd_header);
        }

        /* need one for the header if the first is NOCOPY */
        BUILD_BUG_ON(IWL_MAX_CMD_TBS_PER_TFD > IWL_NUM_OF_TBS - 1);

        for (i = 0; i < IWL_MAX_CMD_TBS_PER_TFD; i++) {
                cmddata[i] = cmd->data[i];
                cmdlen[i] = cmd->len[i];

                if (!cmd->len[i])
                        continue;

                /* need at least IWL_FIRST_TB_SIZE copied */
                if (copy_size < IWL_FIRST_TB_SIZE) {
                        int copy = IWL_FIRST_TB_SIZE - copy_size;

                        if (copy > cmdlen[i])
                                copy = cmdlen[i];
                        cmdlen[i] -= copy;
                        cmddata[i] += copy;
                        copy_size += copy;
                }

                if (cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY) {
                        had_nocopy = true;
                        if (WARN_ON(cmd->dataflags[i] & IWL_HCMD_DFL_DUP)) {
                                idx = -EINVAL;
                                goto free_dup_buf;
                        }
                } else if (cmd->dataflags[i] & IWL_HCMD_DFL_DUP) {
                        /*
                         * This is also a chunk that isn't copied
                         * to the static buffer so set had_nocopy.
                         */
                        had_nocopy = true;

                        /* only allowed once */
                        if (WARN_ON(dup_buf)) {
                                idx = -EINVAL;
                                goto free_dup_buf;
                        }

                        dup_buf = kmemdup(cmddata[i], cmdlen[i],
                                          GFP_ATOMIC);
                        if (!dup_buf)
                                return -ENOMEM;
                } else {
                        /* NOCOPY must not be followed by normal! */
                        if (WARN_ON(had_nocopy)) {
                                idx = -EINVAL;
                                goto free_dup_buf;
                        }
                        copy_size += cmdlen[i];
                }
                cmd_size += cmd->len[i];
        }

        /*
         * If any of the command structures end up being larger than
         * the TFD_MAX_PAYLOAD_SIZE and they aren't dynamically
         * allocated into separate TFDs, then we will need to
         * increase the size of the buffers.
         */
        if (WARN(copy_size > TFD_MAX_PAYLOAD_SIZE,
                 "Command %s (%#x) is too large (%d bytes)\n",
                 iwl_get_cmd_string(trans, cmd->id),
                 cmd->id, copy_size)) {
                idx = -EINVAL;
                goto free_dup_buf;
        }

        spin_lock_bh(&txq->lock);

        if (iwl_queue_space(txq) < ((cmd->flags & CMD_ASYNC) ? 2 : 1)) {
                spin_unlock_bh(&txq->lock);

                IWL_ERR(trans, "No space in command queue\n");
                iwl_op_mode_cmd_queue_full(trans->op_mode);
                idx = -ENOSPC;
                goto free_dup_buf;
        }

        idx = get_cmd_index(txq, txq->write_ptr);
        out_cmd = txq->entries[idx].cmd;
        out_meta = &txq->entries[idx].meta;

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

        /* set up the header */
        if (group_id != 0) {
                out_cmd->hdr_wide.cmd = iwl_cmd_opcode(cmd->id);
                out_cmd->hdr_wide.group_id = group_id;
                out_cmd->hdr_wide.version = iwl_cmd_version(cmd->id);
                out_cmd->hdr_wide.length =
                        cpu_to_le16(cmd_size -
                                    sizeof(struct iwl_cmd_header_wide));
                out_cmd->hdr_wide.reserved = 0;
                out_cmd->hdr_wide.sequence =
                        cpu_to_le16(QUEUE_TO_SEQ(trans_pcie->cmd_queue) |
                                                 INDEX_TO_SEQ(txq->write_ptr));

                cmd_pos = sizeof(struct iwl_cmd_header_wide);
                copy_size = sizeof(struct iwl_cmd_header_wide);
        } else {
                out_cmd->hdr.cmd = iwl_cmd_opcode(cmd->id);
                out_cmd->hdr.sequence =
                        cpu_to_le16(QUEUE_TO_SEQ(trans_pcie->cmd_queue) |
                                                 INDEX_TO_SEQ(txq->write_ptr));
                out_cmd->hdr.group_id = 0;

                cmd_pos = sizeof(struct iwl_cmd_header);
                copy_size = sizeof(struct iwl_cmd_header);
        }

        /* and copy the data that needs to be copied */
        for (i = 0; i < IWL_MAX_CMD_TBS_PER_TFD; i++) {
                int copy;

                if (!cmd->len[i])
                        continue;

                /* copy everything if not nocopy/dup */
                if (!(cmd->dataflags[i] & (IWL_HCMD_DFL_NOCOPY |
                                           IWL_HCMD_DFL_DUP))) {
                        copy = cmd->len[i];

                        memcpy((u8 *)out_cmd + cmd_pos, cmd->data[i], copy);
                        cmd_pos += copy;
                        copy_size += copy;
                        continue;
                }

                /*
                 * Otherwise we need at least IWL_FIRST_TB_SIZE copied
                 * in total (for bi-directional DMA), but copy up to what
                 * we can fit into the payload for debug dump purposes.
                 */
                copy = min_t(int, TFD_MAX_PAYLOAD_SIZE - cmd_pos, cmd->len[i]);

                memcpy((u8 *)out_cmd + cmd_pos, cmd->data[i], copy);
                cmd_pos += copy;

                /* However, treat copy_size the proper way, we need it below */
                if (copy_size < IWL_FIRST_TB_SIZE) {
                        copy = IWL_FIRST_TB_SIZE - copy_size;

                        if (copy > cmd->len[i])
                                copy = cmd->len[i];
                        copy_size += copy;
                }
        }

        IWL_DEBUG_HC(trans,
                     "Sending command %s (%.2x.%.2x), seq: 0x%04X, %d bytes at %d[%d]:%d\n",
                     iwl_get_cmd_string(trans, cmd->id),
                     group_id, out_cmd->hdr.cmd,
                     le16_to_cpu(out_cmd->hdr.sequence),
                     cmd_size, txq->write_ptr, idx, trans_pcie->cmd_queue);

        /* start the TFD with the minimum copy bytes */
        tb0_size = min_t(int, copy_size, IWL_FIRST_TB_SIZE);
        memcpy(&txq->first_tb_bufs[idx], &out_cmd->hdr, tb0_size);
        iwl_pcie_txq_build_tfd(trans, txq,
                               iwl_pcie_get_first_tb_dma(txq, idx),
                               tb0_size, true);

        /* map first command fragment, if any remains */
        if (copy_size > tb0_size) {
                phys_addr = dma_map_single(trans->dev,
                                           ((u8 *)&out_cmd->hdr) + tb0_size,
                                           copy_size - tb0_size,
                                           DMA_TO_DEVICE);
                if (dma_mapping_error(trans->dev, phys_addr)) {
                        iwl_pcie_tfd_unmap(trans, out_meta, txq,
                                           txq->write_ptr);
                        idx = -ENOMEM;
                        goto out;
                }

                iwl_pcie_txq_build_tfd(trans, txq, phys_addr,
                                       copy_size - tb0_size, false);
        }

        /* map the remaining (adjusted) nocopy/dup fragments */
        for (i = 0; i < IWL_MAX_CMD_TBS_PER_TFD; i++) {
                const void *data = cmddata[i];

                if (!cmdlen[i])
                        continue;
                if (!(cmd->dataflags[i] & (IWL_HCMD_DFL_NOCOPY |
                                           IWL_HCMD_DFL_DUP)))
                        continue;
                if (cmd->dataflags[i] & IWL_HCMD_DFL_DUP)
                        data = dup_buf;
                phys_addr = dma_map_single(trans->dev, (void *)data,
                                           cmdlen[i], DMA_TO_DEVICE);
                if (dma_mapping_error(trans->dev, phys_addr)) {
                        iwl_pcie_tfd_unmap(trans, out_meta, txq,
                                           txq->write_ptr);
                        idx = -ENOMEM;
                        goto out;
                }

                iwl_pcie_txq_build_tfd(trans, txq, phys_addr, cmdlen[i], false);
        }

        BUILD_BUG_ON(IWL_TFH_NUM_TBS > sizeof(out_meta->tbs) * BITS_PER_BYTE);
        out_meta->flags = cmd->flags;
        if (WARN_ON_ONCE(txq->entries[idx].free_buf))
                kzfree(txq->entries[idx].free_buf);
        txq->entries[idx].free_buf = dup_buf;

        trace_iwlwifi_dev_hcmd(trans->dev, cmd, cmd_size, &out_cmd->hdr_wide);

        /* start timer if queue currently empty */
        if (txq->read_ptr == txq->write_ptr && txq->wd_timeout)
                mod_timer(&txq->stuck_timer, jiffies + txq->wd_timeout);

        spin_lock_irqsave(&trans_pcie->reg_lock, flags);
        ret = iwl_pcie_set_cmd_in_flight(trans, cmd);
        if (ret < 0) {
                idx = ret;
                spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
                goto out;
        }

        /* Increment and update queue's write index */
        txq->write_ptr = iwl_queue_inc_wrap(txq->write_ptr);
        iwl_pcie_txq_inc_wr_ptr(trans, txq);

        spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);

 out:
        spin_unlock_bh(&txq->lock);
 free_dup_buf:
        if (idx < 0)
                kfree(dup_buf);
        return idx;
}

/*
 * iwl_pcie_hcmd_complete - Pull unused buffers off the queue and reclaim them
 * @rxb: Rx buffer to reclaim
 */
void iwl_pcie_hcmd_complete(struct iwl_trans *trans,
                            struct iwl_rx_cmd_buffer *rxb)
{
        struct iwl_rx_packet *pkt = rxb_addr(rxb);
        u16 sequence = le16_to_cpu(pkt->hdr.sequence);
        u8 group_id;
        u32 cmd_id;
        int txq_id = SEQ_TO_QUEUE(sequence);
        int index = SEQ_TO_INDEX(sequence);
        int cmd_index;
        struct iwl_device_cmd *cmd;
        struct iwl_cmd_meta *meta;
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[trans_pcie->cmd_queue];

        /* 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 != trans_pcie->cmd_queue,
                 "wrong command queue %d (should be %d), sequence 0x%X readp=%d writep=%d\n",
                 txq_id, trans_pcie->cmd_queue, sequence, txq->read_ptr,
                 txq->write_ptr)) {
                iwl_print_hex_error(trans, pkt, 32);
                return;
        }

        spin_lock_bh(&txq->lock);

        cmd_index = get_cmd_index(txq, index);
        cmd = txq->entries[cmd_index].cmd;
        meta = &txq->entries[cmd_index].meta;
        group_id = cmd->hdr.group_id;
        cmd_id = iwl_cmd_id(cmd->hdr.cmd, group_id, 0);

        iwl_pcie_tfd_unmap(trans, meta, txq, index);

        /* Input error checking is done when commands are added to queue. */
        if (meta->flags & CMD_WANT_SKB) {
                struct page *p = rxb_steal_page(rxb);

                meta->source->resp_pkt = pkt;
                meta->source->_rx_page_addr = (unsigned long)page_address(p);
                meta->source->_rx_page_order = trans_pcie->rx_page_order;
        }

        if (meta->flags & CMD_WANT_ASYNC_CALLBACK)
                iwl_op_mode_async_cb(trans->op_mode, cmd);

        iwl_pcie_cmdq_reclaim(trans, txq_id, index);

        if (!(meta->flags & CMD_ASYNC)) {
                if (!test_bit(STATUS_SYNC_HCMD_ACTIVE, &trans->status)) {
                        IWL_WARN(trans,
                                 "HCMD_ACTIVE already clear for command %s\n",
                                 iwl_get_cmd_string(trans, cmd_id));
                }
                clear_bit(STATUS_SYNC_HCMD_ACTIVE, &trans->status);
                IWL_DEBUG_INFO(trans, "Clearing HCMD_ACTIVE for command %s\n",
                               iwl_get_cmd_string(trans, cmd_id));
                wake_up(&trans_pcie->wait_command_queue);
        }

        if (meta->flags & CMD_MAKE_TRANS_IDLE) {
                IWL_DEBUG_INFO(trans, "complete %s - mark trans as idle\n",
                               iwl_get_cmd_string(trans, cmd->hdr.cmd));
                set_bit(STATUS_TRANS_IDLE, &trans->status);
                wake_up(&trans_pcie->d0i3_waitq);
        }

        if (meta->flags & CMD_WAKE_UP_TRANS) {
                IWL_DEBUG_INFO(trans, "complete %s - clear trans idle flag\n",
                               iwl_get_cmd_string(trans, cmd->hdr.cmd));
                clear_bit(STATUS_TRANS_IDLE, &trans->status);
                wake_up(&trans_pcie->d0i3_waitq);
        }

        meta->flags = 0;

        spin_unlock_bh(&txq->lock);
}

#define HOST_COMPLETE_TIMEOUT   (2 * HZ)

static int iwl_pcie_send_hcmd_async(struct iwl_trans *trans,
                                    struct iwl_host_cmd *cmd)
{
        int ret;

        /* An asynchronous command can not expect an SKB to be set. */
        if (WARN_ON(cmd->flags & CMD_WANT_SKB))
                return -EINVAL;

        ret = iwl_pcie_enqueue_hcmd(trans, cmd);
        if (ret < 0) {
                IWL_ERR(trans,
                        "Error sending %s: enqueue_hcmd failed: %d\n",
                        iwl_get_cmd_string(trans, cmd->id), ret);
                return ret;
        }
        return 0;
}

static int iwl_pcie_send_hcmd_sync(struct iwl_trans *trans,
                                   struct iwl_host_cmd *cmd)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans_pcie->txq[trans_pcie->cmd_queue];
        int cmd_idx;
        int ret;

        IWL_DEBUG_INFO(trans, "Attempting to send sync command %s\n",
                       iwl_get_cmd_string(trans, cmd->id));

        if (WARN(test_and_set_bit(STATUS_SYNC_HCMD_ACTIVE,
                                  &trans->status),
                 "Command %s: a command is already active!\n",
                 iwl_get_cmd_string(trans, cmd->id)))
                return -EIO;

        IWL_DEBUG_INFO(trans, "Setting HCMD_ACTIVE for command %s\n",
                       iwl_get_cmd_string(trans, cmd->id));

        if (pm_runtime_suspended(&trans_pcie->pci_dev->dev)) {
                ret = wait_event_timeout(trans_pcie->d0i3_waitq,
                                 pm_runtime_active(&trans_pcie->pci_dev->dev),
                                 msecs_to_jiffies(IWL_TRANS_IDLE_TIMEOUT));
                if (!ret) {
                        IWL_ERR(trans, "Timeout exiting D0i3 before hcmd\n");
                        return -ETIMEDOUT;
                }
        }

        cmd_idx = iwl_pcie_enqueue_hcmd(trans, cmd);
        if (cmd_idx < 0) {
                ret = cmd_idx;
                clear_bit(STATUS_SYNC_HCMD_ACTIVE, &trans->status);
                IWL_ERR(trans,
                        "Error sending %s: enqueue_hcmd failed: %d\n",
                        iwl_get_cmd_string(trans, cmd->id), ret);
                return ret;
        }

        ret = wait_event_timeout(trans_pcie->wait_command_queue,
                                 !test_bit(STATUS_SYNC_HCMD_ACTIVE,
                                           &trans->status),
                                 HOST_COMPLETE_TIMEOUT);
        if (!ret) {
                IWL_ERR(trans, "Error sending %s: time out after %dms.\n",
                        iwl_get_cmd_string(trans, cmd->id),
                        jiffies_to_msecs(HOST_COMPLETE_TIMEOUT));

                IWL_ERR(trans, "Current CMD queue read_ptr %d write_ptr %d\n",
                        txq->read_ptr, txq->write_ptr);

                clear_bit(STATUS_SYNC_HCMD_ACTIVE, &trans->status);
                IWL_DEBUG_INFO(trans, "Clearing HCMD_ACTIVE for command %s\n",
                               iwl_get_cmd_string(trans, cmd->id));
                ret = -ETIMEDOUT;

                iwl_force_nmi(trans);
                iwl_trans_fw_error(trans);

                goto cancel;
        }

        if (test_bit(STATUS_FW_ERROR, &trans->status)) {
                IWL_ERR(trans, "FW error in SYNC CMD %s\n",
                        iwl_get_cmd_string(trans, cmd->id));
                dump_stack();
                ret = -EIO;
                goto cancel;
        }

        if (!(cmd->flags & CMD_SEND_IN_RFKILL) &&
            test_bit(STATUS_RFKILL_OPMODE, &trans->status)) {
                IWL_DEBUG_RF_KILL(trans, "RFKILL in SYNC CMD... no rsp\n");
                ret = -ERFKILL;
                goto cancel;
        }

        if ((cmd->flags & CMD_WANT_SKB) && !cmd->resp_pkt) {
                IWL_ERR(trans, "Error: Response NULL in '%s'\n",
                        iwl_get_cmd_string(trans, cmd->id));
                ret = -EIO;
                goto cancel;
        }

        return 0;

cancel:
        if (cmd->flags & CMD_WANT_SKB) {
                /*
                 * Cancel the CMD_WANT_SKB flag for the cmd in the
                 * TX cmd queue. Otherwise in case the cmd comes
                 * in later, it will possibly set an invalid
                 * address (cmd->meta.source).
                 */
                txq->entries[cmd_idx].meta.flags &= ~CMD_WANT_SKB;
        }

        if (cmd->resp_pkt) {
                iwl_free_resp(cmd);
                cmd->resp_pkt = NULL;
        }

        return ret;
}

int iwl_trans_pcie_send_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
{
        if (!(cmd->flags & CMD_SEND_IN_RFKILL) &&
            test_bit(STATUS_RFKILL_OPMODE, &trans->status)) {
                IWL_DEBUG_RF_KILL(trans, "Dropping CMD 0x%x: RF KILL\n",
                                  cmd->id);
                return -ERFKILL;
        }

        if (cmd->flags & CMD_ASYNC)
                return iwl_pcie_send_hcmd_async(trans, cmd);

        /* We still can fail on RFKILL that can be asserted while we wait */
        return iwl_pcie_send_hcmd_sync(trans, cmd);
}

static int iwl_fill_data_tbs(struct iwl_trans *trans, struct sk_buff *skb,
                             struct iwl_txq *txq, u8 hdr_len,
                             struct iwl_cmd_meta *out_meta,
                             struct iwl_device_cmd *dev_cmd, u16 tb1_len)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u16 tb2_len;
        int i;

        /*
         * Set up TFD's third entry to point directly to remainder
         * of skb's head, if any
         */
        tb2_len = skb_headlen(skb) - hdr_len;

        if (tb2_len > 0) {
                dma_addr_t tb2_phys = dma_map_single(trans->dev,
                                                     skb->data + hdr_len,
                                                     tb2_len, DMA_TO_DEVICE);
                if (unlikely(dma_mapping_error(trans->dev, tb2_phys))) {
                        iwl_pcie_tfd_unmap(trans, out_meta, txq,
                                           txq->write_ptr);
                        return -EINVAL;
                }
                iwl_pcie_txq_build_tfd(trans, txq, tb2_phys, tb2_len, false);
        }

        /* set up the remaining entries to point to the data */
        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
                dma_addr_t tb_phys;
                int tb_idx;

                if (!skb_frag_size(frag))
                        continue;

                tb_phys = skb_frag_dma_map(trans->dev, frag, 0,
                                           skb_frag_size(frag), DMA_TO_DEVICE);

                if (unlikely(dma_mapping_error(trans->dev, tb_phys))) {
                        iwl_pcie_tfd_unmap(trans, out_meta, txq,
                                           txq->write_ptr);
                        return -EINVAL;
                }
                tb_idx = iwl_pcie_txq_build_tfd(trans, txq, tb_phys,
                                                skb_frag_size(frag), false);

                out_meta->tbs |= BIT(tb_idx);
        }

        trace_iwlwifi_dev_tx(trans->dev, skb,
                             iwl_pcie_get_tfd(trans_pcie, txq, txq->write_ptr),
                             trans_pcie->tfd_size,
                             &dev_cmd->hdr, IWL_FIRST_TB_SIZE + tb1_len,
                             hdr_len);
        trace_iwlwifi_dev_tx_data(trans->dev, skb, hdr_len);
        return 0;
}

#ifdef CONFIG_INET
struct iwl_tso_hdr_page *get_page_hdr(struct iwl_trans *trans, size_t len)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_tso_hdr_page *p = this_cpu_ptr(trans_pcie->tso_hdr_page);

        if (!p->page)
                goto alloc;

        /* enough room on this page */
        if (p->pos + len < (u8 *)page_address(p->page) + PAGE_SIZE)
                return p;

        /* We don't have enough room on this page, get a new one. */
        __free_page(p->page);

alloc:
        p->page = alloc_page(GFP_ATOMIC);
        if (!p->page)
                return NULL;
        p->pos = page_address(p->page);
        return p;
}

static void iwl_compute_pseudo_hdr_csum(void *iph, struct tcphdr *tcph,
                                        bool ipv6, unsigned int len)
{
        if (ipv6) {
                struct ipv6hdr *iphv6 = iph;

                tcph->check = ~csum_ipv6_magic(&iphv6->saddr, &iphv6->daddr,
                                               len + tcph->doff * 4,
                                               IPPROTO_TCP, 0);
        } else {
                struct iphdr *iphv4 = iph;

                ip_send_check(iphv4);
                tcph->check = ~csum_tcpudp_magic(iphv4->saddr, iphv4->daddr,
                                                 len + tcph->doff * 4,
                                                 IPPROTO_TCP, 0);
        }
}

static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
                                   struct iwl_txq *txq, u8 hdr_len,
                                   struct iwl_cmd_meta *out_meta,
                                   struct iwl_device_cmd *dev_cmd, u16 tb1_len)
{
        struct iwl_tx_cmd *tx_cmd = (void *)dev_cmd->payload;
        struct iwl_trans_pcie *trans_pcie = txq->trans_pcie;
        struct ieee80211_hdr *hdr = (void *)skb->data;
        unsigned int snap_ip_tcp_hdrlen, ip_hdrlen, total_len, hdr_room;
        unsigned int mss = skb_shinfo(skb)->gso_size;
        u16 length, iv_len, amsdu_pad;
        u8 *start_hdr;
        struct iwl_tso_hdr_page *hdr_page;
        struct page **page_ptr;
        int ret;
        struct tso_t tso;

        /* if the packet is protected, then it must be CCMP or GCMP */
        BUILD_BUG_ON(IEEE80211_CCMP_HDR_LEN != IEEE80211_GCMP_HDR_LEN);
        iv_len = ieee80211_has_protected(hdr->frame_control) ?
                IEEE80211_CCMP_HDR_LEN : 0;

        trace_iwlwifi_dev_tx(trans->dev, skb,
                             iwl_pcie_get_tfd(trans_pcie, txq, txq->write_ptr),
                             trans_pcie->tfd_size,
                             &dev_cmd->hdr, IWL_FIRST_TB_SIZE + tb1_len, 0);

        ip_hdrlen = skb_transport_header(skb) - skb_network_header(skb);
        snap_ip_tcp_hdrlen = 8 + ip_hdrlen + tcp_hdrlen(skb);
        total_len = skb->len - snap_ip_tcp_hdrlen - hdr_len - iv_len;
        amsdu_pad = 0;

        /* total amount of header we may need for this A-MSDU */
        hdr_room = DIV_ROUND_UP(total_len, mss) *
                (3 + snap_ip_tcp_hdrlen + sizeof(struct ethhdr)) + iv_len;

        /* Our device supports 9 segments at most, it will fit in 1 page */
        hdr_page = get_page_hdr(trans, hdr_room);
        if (!hdr_page)
                return -ENOMEM;

        get_page(hdr_page->page);
        start_hdr = hdr_page->pos;
        page_ptr = (void *)((u8 *)skb->cb + trans_pcie->page_offs);
        *page_ptr = hdr_page->page;
        memcpy(hdr_page->pos, skb->data + hdr_len, iv_len);
        hdr_page->pos += iv_len;

        /*
         * Pull the ieee80211 header + IV to be able to use TSO core,
         * we will restore it for the tx_status flow.
         */
        skb_pull(skb, hdr_len + iv_len);

        /*
         * Remove the length of all the headers that we don't actually
         * have in the MPDU by themselves, but that we duplicate into
         * all the different MSDUs inside the A-MSDU.
         */
        le16_add_cpu(&tx_cmd->len, -snap_ip_tcp_hdrlen);

        tso_start(skb, &tso);

        while (total_len) {
                /* this is the data left for this subframe */
                unsigned int data_left =
                        min_t(unsigned int, mss, total_len);
                struct sk_buff *csum_skb = NULL;
                unsigned int hdr_tb_len;
                dma_addr_t hdr_tb_phys;
                struct tcphdr *tcph;
                u8 *iph, *subf_hdrs_start = hdr_page->pos;

                total_len -= data_left;

                memset(hdr_page->pos, 0, amsdu_pad);
                hdr_page->pos += amsdu_pad;
                amsdu_pad = (4 - (sizeof(struct ethhdr) + snap_ip_tcp_hdrlen +
                                  data_left)) & 0x3;
                ether_addr_copy(hdr_page->pos, ieee80211_get_DA(hdr));
                hdr_page->pos += ETH_ALEN;
                ether_addr_copy(hdr_page->pos, ieee80211_get_SA(hdr));
                hdr_page->pos += ETH_ALEN;

                length = snap_ip_tcp_hdrlen + data_left;
                *((__be16 *)hdr_page->pos) = cpu_to_be16(length);
                hdr_page->pos += sizeof(length);

                /*
                 * This will copy the SNAP as well which will be considered
                 * as MAC header.
                 */
                tso_build_hdr(skb, hdr_page->pos, &tso, data_left, !total_len);
                iph = hdr_page->pos + 8;
                tcph = (void *)(iph + ip_hdrlen);

                /* For testing on current hardware only */
                if (trans_pcie->sw_csum_tx) {
                        csum_skb = alloc_skb(data_left + tcp_hdrlen(skb),
                                             GFP_ATOMIC);
                        if (!csum_skb) {
                                ret = -ENOMEM;
                                goto out_unmap;
                        }

                        iwl_compute_pseudo_hdr_csum(iph, tcph,
                                                    skb->protocol ==
                                                        htons(ETH_P_IPV6),
                                                    data_left);

                        skb_put_data(csum_skb, tcph, tcp_hdrlen(skb));
                        skb_reset_transport_header(csum_skb);
                        csum_skb->csum_start =
                                (unsigned char *)tcp_hdr(csum_skb) -
                                                 csum_skb->head;
                }

                hdr_page->pos += snap_ip_tcp_hdrlen;

                hdr_tb_len = hdr_page->pos - start_hdr;
                hdr_tb_phys = dma_map_single(trans->dev, start_hdr,
                                             hdr_tb_len, DMA_TO_DEVICE);
                if (unlikely(dma_mapping_error(trans->dev, hdr_tb_phys))) {
                        dev_kfree_skb(csum_skb);
                        ret = -EINVAL;
                        goto out_unmap;
                }
                iwl_pcie_txq_build_tfd(trans, txq, hdr_tb_phys,
                                       hdr_tb_len, false);
                trace_iwlwifi_dev_tx_tso_chunk(trans->dev, start_hdr,
                                               hdr_tb_len);
                /* add this subframe's headers' length to the tx_cmd */
                le16_add_cpu(&tx_cmd->len, hdr_page->pos - subf_hdrs_start);

                /* prepare the start_hdr for the next subframe */
                start_hdr = hdr_page->pos;

                /* put the payload */
                while (data_left) {
                        unsigned int size = min_t(unsigned int, tso.size,
                                                  data_left);
                        dma_addr_t tb_phys;

                        if (trans_pcie->sw_csum_tx)
                                skb_put_data(csum_skb, tso.data, size);

                        tb_phys = dma_map_single(trans->dev, tso.data,
                                                 size, DMA_TO_DEVICE);
                        if (unlikely(dma_mapping_error(trans->dev, tb_phys))) {
                                dev_kfree_skb(csum_skb);
                                ret = -EINVAL;
                                goto out_unmap;
                        }

                        iwl_pcie_txq_build_tfd(trans, txq, tb_phys,
                                               size, false);
                        trace_iwlwifi_dev_tx_tso_chunk(trans->dev, tso.data,
                                                       size);

                        data_left -= size;
                        tso_build_data(skb, &tso, size);
                }

                /* For testing on early hardware only */
                if (trans_pcie->sw_csum_tx) {
                        __wsum csum;

                        csum = skb_checksum(csum_skb,
                                            skb_checksum_start_offset(csum_skb),
                                            csum_skb->len -
                                            skb_checksum_start_offset(csum_skb),
                                            0);
                        dev_kfree_skb(csum_skb);
                        dma_sync_single_for_cpu(trans->dev, hdr_tb_phys,
                                                hdr_tb_len, DMA_TO_DEVICE);
                        tcph->check = csum_fold(csum);
                        dma_sync_single_for_device(trans->dev, hdr_tb_phys,
                                                   hdr_tb_len, DMA_TO_DEVICE);
                }
        }

        /* re -add the WiFi header and IV */
        skb_push(skb, hdr_len + iv_len);

        return 0;

out_unmap:
        iwl_pcie_tfd_unmap(trans, out_meta, txq, txq->write_ptr);
        return ret;
}
#else /* CONFIG_INET */
static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
                                   struct iwl_txq *txq, u8 hdr_len,
                                   struct iwl_cmd_meta *out_meta,
                                   struct iwl_device_cmd *dev_cmd, u16 tb1_len)
{
        /* No A-MSDU without CONFIG_INET */
        WARN_ON(1);

        return -1;
}
#endif /* CONFIG_INET */

int iwl_trans_pcie_tx(struct iwl_trans *trans, struct sk_buff *skb,
                      struct iwl_device_cmd *dev_cmd, int txq_id)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct ieee80211_hdr *hdr;
        struct iwl_tx_cmd *tx_cmd = (struct iwl_tx_cmd *)dev_cmd->payload;
        struct iwl_cmd_meta *out_meta;
        struct iwl_txq *txq;
        dma_addr_t tb0_phys, tb1_phys, scratch_phys;
        void *tb1_addr;
        void *tfd;
        u16 len, tb1_len;
        bool wait_write_ptr;
        __le16 fc;
        u8 hdr_len;
        u16 wifi_seq;
        bool amsdu;

        txq = trans_pcie->txq[txq_id];

        if (WARN_ONCE(!test_bit(txq_id, trans_pcie->queue_used),
                      "TX on unused queue %d\n", txq_id))
                return -EINVAL;

        if (unlikely(trans_pcie->sw_csum_tx &&
                     skb->ip_summed == CHECKSUM_PARTIAL)) {
                int offs = skb_checksum_start_offset(skb);
                int csum_offs = offs + skb->csum_offset;
                __wsum csum;

                if (skb_ensure_writable(skb, csum_offs + sizeof(__sum16)))
                        return -1;

                csum = skb_checksum(skb, offs, skb->len - offs, 0);
                *(__sum16 *)(skb->data + csum_offs) = csum_fold(csum);

                skb->ip_summed = CHECKSUM_UNNECESSARY;
        }

        if (skb_is_nonlinear(skb) &&
            skb_shinfo(skb)->nr_frags > IWL_PCIE_MAX_FRAGS(trans_pcie) &&
            __skb_linearize(skb))
                return -ENOMEM;

        /* mac80211 always puts the full header into the SKB's head,
         * so there's no need to check if it's readable there
         */
        hdr = (struct ieee80211_hdr *)skb->data;
        fc = hdr->frame_control;
        hdr_len = ieee80211_hdrlen(fc);

        spin_lock(&txq->lock);

        if (iwl_queue_space(txq) < txq->high_mark) {
                iwl_stop_queue(trans, txq);

                /* don't put the packet on the ring, if there is no room */
                if (unlikely(iwl_queue_space(txq) < 3)) {
                        struct iwl_device_cmd **dev_cmd_ptr;

                        dev_cmd_ptr = (void *)((u8 *)skb->cb +
                                               trans_pcie->dev_cmd_offs);

                        *dev_cmd_ptr = dev_cmd;
                        __skb_queue_tail(&txq->overflow_q, skb);

                        spin_unlock(&txq->lock);
                        return 0;
                }
        }

        /* In AGG mode, the index in the ring must correspond to the WiFi
         * sequence number. This is a HW requirements to help the SCD to parse
         * the BA.
         * Check here that the packets are in the right place on the ring.
         */
        wifi_seq = IEEE80211_SEQ_TO_SN(le16_to_cpu(hdr->seq_ctrl));
        WARN_ONCE(txq->ampdu &&
                  (wifi_seq & 0xff) != txq->write_ptr,
                  "Q: %d WiFi Seq %d tfdNum %d",
                  txq_id, wifi_seq, txq->write_ptr);

        /* Set up driver data for this TFD */
        txq->entries[txq->write_ptr].skb = skb;
        txq->entries[txq->write_ptr].cmd = dev_cmd;

        dev_cmd->hdr.sequence =
                cpu_to_le16((u16)(QUEUE_TO_SEQ(txq_id) |
                            INDEX_TO_SEQ(txq->write_ptr)));

        tb0_phys = iwl_pcie_get_first_tb_dma(txq, txq->write_ptr);
        scratch_phys = tb0_phys + sizeof(struct iwl_cmd_header) +
                       offsetof(struct iwl_tx_cmd, scratch);

        tx_cmd->dram_lsb_ptr = cpu_to_le32(scratch_phys);
        tx_cmd->dram_msb_ptr = iwl_get_dma_hi_addr(scratch_phys);

        /* Set up first empty entry in queue's array of Tx/cmd buffers */
        out_meta = &txq->entries[txq->write_ptr].meta;
        out_meta->flags = 0;

        /*
         * The second TB (tb1) points to the remainder of the TX command
         * and the 802.11 header - dword aligned size
         * (This calculation modifies the TX command, so do it before the
         * setup of the first TB)
         */
        len = sizeof(struct iwl_tx_cmd) + sizeof(struct iwl_cmd_header) +
              hdr_len - IWL_FIRST_TB_SIZE;
        /* do not align A-MSDU to dword as the subframe header aligns it */
        amsdu = ieee80211_is_data_qos(fc) &&
                (*ieee80211_get_qos_ctl(hdr) &
                 IEEE80211_QOS_CTL_A_MSDU_PRESENT);
        if (trans_pcie->sw_csum_tx || !amsdu) {
                tb1_len = ALIGN(len, 4);
                /* Tell NIC about any 2-byte padding after MAC header */
                if (tb1_len != len)
                        tx_cmd->tx_flags |= TX_CMD_FLG_MH_PAD_MSK;
        } else {
                tb1_len = len;
        }

        /*
         * The first TB points to bi-directional DMA data, we'll
         * memcpy the data into it later.
         */
        iwl_pcie_txq_build_tfd(trans, txq, tb0_phys,
                               IWL_FIRST_TB_SIZE, true);

        /* there must be data left over for TB1 or this code must be changed */
        BUILD_BUG_ON(sizeof(struct iwl_tx_cmd) < IWL_FIRST_TB_SIZE);

        /* map the data for TB1 */
        tb1_addr = ((u8 *)&dev_cmd->hdr) + IWL_FIRST_TB_SIZE;
        tb1_phys = dma_map_single(trans->dev, tb1_addr, tb1_len, DMA_TO_DEVICE);
        if (unlikely(dma_mapping_error(trans->dev, tb1_phys)))
                goto out_err;
        iwl_pcie_txq_build_tfd(trans, txq, tb1_phys, tb1_len, false);

        if (amsdu) {
                if (unlikely(iwl_fill_data_tbs_amsdu(trans, skb, txq, hdr_len,
                                                     out_meta, dev_cmd,
                                                     tb1_len)))
                        goto out_err;
        } else if (unlikely(iwl_fill_data_tbs(trans, skb, txq, hdr_len,
                                       out_meta, dev_cmd, tb1_len))) {
                goto out_err;
        }

        /* building the A-MSDU might have changed this data, so memcpy it now */
        memcpy(&txq->first_tb_bufs[txq->write_ptr], &dev_cmd->hdr,
               IWL_FIRST_TB_SIZE);

        tfd = iwl_pcie_get_tfd(trans_pcie, txq, txq->write_ptr);
        /* Set up entry for this TFD in Tx byte-count array */
        iwl_pcie_txq_update_byte_cnt_tbl(trans, txq, le16_to_cpu(tx_cmd->len),
                                         iwl_pcie_tfd_get_num_tbs(trans, tfd));

        wait_write_ptr = ieee80211_has_morefrags(fc);

        /* start timer if queue currently empty */
        if (txq->read_ptr == txq->write_ptr) {
                if (txq->wd_timeout) {
                        /*
                         * If the TXQ is active, then set the timer, if not,
                         * set the timer in remainder so that the timer will
                         * be armed with the right value when the station will
                         * wake up.
                         */
                        if (!txq->frozen)
                                mod_timer(&txq->stuck_timer,
                                          jiffies + txq->wd_timeout);
                        else
                                txq->frozen_expiry_remainder = txq->wd_timeout;
                }
                IWL_DEBUG_RPM(trans, "Q: %d first tx - take ref\n", txq->id);
                iwl_trans_ref(trans);
        }

        /* Tell device the write index *just past* this latest filled TFD */
        txq->write_ptr = iwl_queue_inc_wrap(txq->write_ptr);
        if (!wait_write_ptr)
                iwl_pcie_txq_inc_wr_ptr(trans, txq);

        /*
         * At this point the frame is "transmitted" successfully
         * and we will get a TX status notification eventually.
         */
        spin_unlock(&txq->lock);
        return 0;
out_err:
        spin_unlock(&txq->lock);
        return -1;
}