drivers/net/wireless/iwlwifi/iwl-tx.c

/******************************************************************************
 *
 * Copyright(c) 2003 - 2011 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 <linux/sched.h>
#include <linux/slab.h>
#include <net/mac80211.h>
#include "iwl-eeprom.h"
#include "iwl-agn.h"
#include "iwl-dev.h"
#include "iwl-core.h"
#include "iwl-sta.h"
#include "iwl-io.h"
#include "iwl-helpers.h"

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

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

	if (priv->cfg->base_params->shadow_reg_enable) {
		/* shadow register enabled */
		iwl_write32(priv, HBUS_TARG_WRPTR,
			    txq->q.write_ptr | (txq_id << 8));
	} else {
		/* 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,
					"Tx queue %d requesting wakeup,"
					" GP1 = 0x%x\n", txq_id, reg);
				iwl_set_bit(priv, CSR_GP_CNTRL,
					CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
				return;
			}

			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;
}

static inline dma_addr_t iwl_tfd_tb_get_addr(struct iwl_tfd *tfd, u8 idx)
{
	struct iwl_tfd_tb *tb = &tfd->tbs[idx];

	dma_addr_t addr = get_unaligned_le32(&tb->lo);
	if (sizeof(dma_addr_t) > sizeof(u32))
		addr |=
		((dma_addr_t)(le16_to_cpu(tb->hi_n_len) & 0xF) << 16) << 16;

	return addr;
}

static inline u16 iwl_tfd_tb_get_len(struct iwl_tfd *tfd, u8 idx)
{
	struct iwl_tfd_tb *tb = &tfd->tbs[idx];

	return le16_to_cpu(tb->hi_n_len) >> 4;
}

static inline void iwl_tfd_set_tb(struct iwl_tfd *tfd, u8 idx,
				  dma_addr_t addr, u16 len)
{
	struct iwl_tfd_tb *tb = &tfd->tbs[idx];
	u16 hi_n_len = len << 4;

	put_unaligned_le32(addr, &tb->lo);
	if (sizeof(dma_addr_t) > sizeof(u32))
		hi_n_len |= ((addr >> 16) >> 16) & 0xF;

	tb->hi_n_len = cpu_to_le16(hi_n_len);

	tfd->num_tbs = idx + 1;
}

static inline u8 iwl_tfd_get_num_tbs(struct iwl_tfd *tfd)
{
	return tfd->num_tbs & 0x1f;
}

static void iwlagn_unmap_tfd(struct iwl_priv *priv, struct iwl_cmd_meta *meta,
			     struct iwl_tfd *tfd, int dma_dir)
{
	struct pci_dev *dev = priv->pci_dev;
	int i;
	int num_tbs;

	/* Sanity check on number of chunks */
	num_tbs = iwl_tfd_get_num_tbs(tfd);

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

	/* Unmap tx_cmd */
	if (num_tbs)
		pci_unmap_single(dev,
				dma_unmap_addr(meta, mapping),
				dma_unmap_len(meta, len),
				PCI_DMA_BIDIRECTIONAL);

	/* Unmap chunks, if any. */
	for (i = 1; i < num_tbs; i++)
		pci_unmap_single(dev, iwl_tfd_tb_get_addr(tfd, i),
				iwl_tfd_tb_get_len(tfd, i), dma_dir);
}

/**
 * iwlagn_txq_free_tfd - Free all chunks referenced by TFD [txq->q.read_ptr]
 * @priv - driver private data
 * @txq - tx queue
 *
 * Does NOT advance any TFD circular buffer read/write indexes
 * Does NOT free the TFD itself (which is within circular buffer)
 */
void iwlagn_txq_free_tfd(struct iwl_priv *priv, struct iwl_tx_queue *txq)
{
	struct iwl_tfd *tfd_tmp = txq->tfds;
	int index = txq->q.read_ptr;

	iwlagn_unmap_tfd(priv, &txq->meta[index], &tfd_tmp[index],
			 PCI_DMA_TODEVICE);

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

		skb = txq->txb[txq->q.read_ptr].skb;

		/* can be called from irqs-disabled context */
		if (skb) {
			dev_kfree_skb_any(skb);
			txq->txb[txq->q.read_ptr].skb = NULL;
		}
	}
}

int iwlagn_txq_attach_buf_to_tfd(struct iwl_priv *priv,
				 struct iwl_tx_queue *txq,
				 dma_addr_t addr, u16 len,
				 u8 reset)
{
	struct iwl_queue *q;
	struct iwl_tfd *tfd, *tfd_tmp;
	u32 num_tbs;

	q = &txq->q;
	tfd_tmp = txq->tfds;
	tfd = &tfd_tmp[q->write_ptr];

	if (reset)
		memset(tfd, 0, sizeof(*tfd));

	num_tbs = iwl_tfd_get_num_tbs(tfd);

	/* Each TFD can point to a maximum 20 Tx buffers */
	if (num_tbs >= IWL_NUM_OF_TBS) {
		IWL_ERR(priv, "Error can not send more than %d chunks\n",
			  IWL_NUM_OF_TBS);
		return -EINVAL;
	}

	if (WARN_ON(addr & ~DMA_BIT_MASK(36)))
		return -EINVAL;

	if (unlikely(addr & ~IWL_TX_DMA_MASK))
		IWL_ERR(priv, "Unaligned address = %llx\n",
			  (unsigned long long)addr);

	iwl_tfd_set_tb(tfd, num_tbs, addr, len);

	return 0;
}

/*
 * Tell nic where to find circular buffer of Tx Frame Descriptors for
 * given Tx queue, and enable the DMA channel used for that queue.
 *
 * supports up to 16 Tx queues in DRAM, mapped to up to 8 Tx DMA
 * channels supported in hardware.
 */
static int iwlagn_tx_queue_init(struct iwl_priv *priv, struct iwl_tx_queue *txq)
{
	int txq_id = txq->q.id;

	/* Circular buffer (TFD queue in DRAM) physical base address */
	iwl_write_direct32(priv, FH_MEM_CBBC_QUEUE(txq_id),
			     txq->q.dma_addr >> 8);

	return 0;
}

/**
 * iwl_tx_queue_unmap -  Unmap any remaining DMA mappings and free skb's
 */
void iwl_tx_queue_unmap(struct iwl_priv *priv, int txq_id)
{
	struct iwl_tx_queue *txq = &priv->txq[txq_id];
	struct iwl_queue *q = &txq->q;

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

	 while (q->write_ptr != q->read_ptr) {
		iwlagn_txq_free_tfd(priv, txq);
		q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd);
	}
}

/**
 * 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 device *dev = &priv->pci_dev->dev;
	int i;

	iwl_tx_queue_unmap(priv, txq_id);

	/* 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)
		dma_free_coherent(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));
}

/**
 * iwl_cmd_queue_unmap - Unmap any remaining DMA mappings from command queue
 */
void iwl_cmd_queue_unmap(struct iwl_priv *priv)
{
	struct iwl_tx_queue *txq = &priv->txq[priv->cmd_queue];
	struct iwl_queue *q = &txq->q;
	int i;

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

	while (q->read_ptr != q->write_ptr) {
		i = get_cmd_index(q, q->read_ptr);

		if (txq->meta[i].flags & CMD_MAPPED) {
			iwlagn_unmap_tfd(priv, &txq->meta[i], &txq->tfds[i],
					 PCI_DMA_BIDIRECTIONAL);
			txq->meta[i].flags = 0;
		}

		q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd);
	}
}

/**
 * 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[priv->cmd_queue];
	struct device *dev = &priv->pci_dev->dev;
	int i;

	iwl_cmd_queue_unmap(priv);

	/* 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)
		dma_free_coherent(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));
}

/*************** 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_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;
}


/**
 * 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. */
	if (WARN_ON(!is_power_of_2(count)))
		return -EINVAL;

	/* 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 = 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 device *dev = &priv->pci_dev->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 != priv->cmd_queue) {
		txq->txb = kzalloc(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 = dma_alloc_coherent(dev, tfd_sz, &txq->q.dma_addr,
				       GFP_KERNEL);
	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;

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

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

	len = sizeof(struct iwl_device_cmd);
	for (i = 0; i < slots_num; i++) {
		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;

	/*
	 * For the default queues 0-3, set up the swq_id
	 * already -- all others need to get one later
	 * (if they need one at all).
	 */
	if (txq_id < 4)
		iwl_set_swq_id(txq, txq_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 */
	ret = iwl_queue_init(priv, &txq->q, TFD_QUEUE_SIZE_MAX, slots_num, txq_id);
	if (ret)
		return ret;

	/* Tell device where to find queue */
	iwlagn_tx_queue_init(priv, txq);

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

	return -ENOMEM;
}

void iwl_tx_queue_reset(struct iwl_priv *priv, struct iwl_tx_queue *txq,
			int slots_num, u32 txq_id)
{
	memset(txq->meta, 0, sizeof(struct iwl_cmd_meta) * slots_num);

	txq->need_update = 0;

	/* 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 */
	iwlagn_tx_queue_init(priv, txq);
}

/*************** 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[priv->cmd_queue];
	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;
	u32 idx;
	u16 copy_size, cmd_size;
	bool is_ct_kill = false;
	bool had_nocopy = false;
	int i;
	u8 *cmd_dest;
#ifdef CONFIG_IWLWIFI_DEVICE_TRACING
	const void *trace_bufs[IWL_MAX_CMD_TFDS + 1] = {};
	int trace_lens[IWL_MAX_CMD_TFDS + 1] = {};
	int trace_idx;
#endif

	if (test_bit(STATUS_FW_ERROR, &priv->status)) {
		IWL_WARN(priv, "fw recovery, no hcmd send\n");
		return -EIO;
	}

	copy_size = sizeof(out_cmd->hdr);
	cmd_size = sizeof(out_cmd->hdr);

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

	for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
		if (!cmd->len[i])
			continue;
		if (cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY) {
			had_nocopy = true;
		} else {
			/* NOCOPY must not be followed by normal! */
			if (WARN_ON(had_nocopy))
				return -EINVAL;
			copy_size += cmd->len[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_ON(copy_size > TFD_MAX_PAYLOAD_SIZE))
		return -EINVAL;

	if (iwl_is_rfkill(priv) || iwl_is_ctkill(priv)) {
		IWL_WARN(priv, "Not sending command - %s KILL\n",
			 iwl_is_rfkill(priv) ? "RF" : "CT");
		return -EIO;
	}

	spin_lock_irqsave(&priv->hcmd_lock, flags);

	if (iwl_queue_space(q) < ((cmd->flags & CMD_ASYNC) ? 2 : 1)) {
		spin_unlock_irqrestore(&priv->hcmd_lock, flags);

		IWL_ERR(priv, "No space in command queue\n");
		is_ct_kill = iwl_check_for_ct_kill(priv);
		if (!is_ct_kill) {
			IWL_ERR(priv, "Restarting adapter due to queue full\n");
			iwlagn_fw_error(priv, false);
		}
		return -ENOSPC;
	}

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

	if (WARN_ON(out_meta->flags & CMD_MAPPED)) {
		spin_unlock_irqrestore(&priv->hcmd_lock, flags);
		return -ENOSPC;
	}

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

	/* set up the header */

	out_cmd->hdr.cmd = cmd->id;
	out_cmd->hdr.flags = 0;
	out_cmd->hdr.sequence = cpu_to_le16(QUEUE_TO_SEQ(priv->cmd_queue) |
					    INDEX_TO_SEQ(q->write_ptr));

	/* and copy the data that needs to be copied */

	cmd_dest = &out_cmd->cmd.payload[0];
	for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
		if (!cmd->len[i])
			continue;
		if (cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY)
			break;
		memcpy(cmd_dest, cmd->data[i], cmd->len[i]);
		cmd_dest += cmd->len[i];
	}

	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), cmd_size,
			q->write_ptr, idx, priv->cmd_queue);

	phys_addr = pci_map_single(priv->pci_dev, &out_cmd->hdr,
				   copy_size, PCI_DMA_BIDIRECTIONAL);
	if (unlikely(pci_dma_mapping_error(priv->pci_dev, phys_addr))) {
		idx = -ENOMEM;
		goto out;
	}

	dma_unmap_addr_set(out_meta, mapping, phys_addr);
	dma_unmap_len_set(out_meta, len, copy_size);

	iwlagn_txq_attach_buf_to_tfd(priv, txq, phys_addr, copy_size, 1);
#ifdef CONFIG_IWLWIFI_DEVICE_TRACING
	trace_bufs[0] = &out_cmd->hdr;
	trace_lens[0] = copy_size;
	trace_idx = 1;
#endif

	for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
		if (!cmd->len[i])
			continue;
		if (!(cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY))
			continue;
		phys_addr = pci_map_single(priv->pci_dev, (void *)cmd->data[i],
					   cmd->len[i], PCI_DMA_BIDIRECTIONAL);
		if (pci_dma_mapping_error(priv->pci_dev, phys_addr)) {
			iwlagn_unmap_tfd(priv, out_meta,
					 &txq->tfds[q->write_ptr],
					 PCI_DMA_BIDIRECTIONAL);
			idx = -ENOMEM;
			goto out;
		}

		iwlagn_txq_attach_buf_to_tfd(priv, txq, phys_addr,
					     cmd->len[i], 0);
#ifdef CONFIG_IWLWIFI_DEVICE_TRACING
		trace_bufs[trace_idx] = cmd->data[i];
		trace_lens[trace_idx] = cmd->len[i];
		trace_idx++;
#endif
	}

	out_meta->flags = cmd->flags | CMD_MAPPED;

	txq->need_update = 1;

	/* check that tracing gets all possible blocks */
	BUILD_BUG_ON(IWL_MAX_CMD_TFDS + 1 != 3);
#ifdef CONFIG_IWLWIFI_DEVICE_TRACING
	trace_iwlwifi_dev_hcmd(priv, cmd->flags,
			       trace_bufs[0], trace_lens[0],
			       trace_bufs[1], trace_lens[1],
			       trace_bufs[2], trace_lens[2]);
#endif

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

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

/**
 * 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)
{
	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;
	}

	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);
			iwlagn_fw_error(priv, false);
		}

	}
}

/**
 * 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 = rxb_addr(rxb);
	u16 sequence = le16_to_cpu(pkt->hdr.sequence);
	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_tx_queue *txq = &priv->txq[priv->cmd_queue];
	unsigned long flags;

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

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

	iwlagn_unmap_tfd(priv, meta, &txq->tfds[index], PCI_DMA_BIDIRECTIONAL);

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

	spin_lock_irqsave(&priv->hcmd_lock, flags);

	iwl_hcmd_queue_reclaim(priv, txq_id, index);

	if (!(meta->flags & CMD_ASYNC)) {
		clear_bit(STATUS_HCMD_ACTIVE, &priv->status);
		IWL_DEBUG_INFO(priv, "Clearing HCMD_ACTIVE for command %s\n",
			       get_cmd_string(cmd->hdr.cmd));
		wake_up_interruptible(&priv->wait_command_queue);
	}

	/* Mark as unmapped */
	meta->flags = 0;

	spin_unlock_irqrestore(&priv->hcmd_lock, flags);
}