iwlwifi: pcie: properly implement NAPI

[linux-2.6-microblaze.git] / drivers / net / wireless / intel / iwlwifi / pcie / rx.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * Copyright (C) 2003-2014, 2018-2020 Intel Corporation
 * Copyright (C) 2013-2015 Intel Mobile Communications GmbH
 * Copyright (C) 2016-2017 Intel Deutschland GmbH
 */
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/gfp.h>

#include "iwl-prph.h"
#include "iwl-io.h"
#include "internal.h"
#include "iwl-op-mode.h"
#include "iwl-context-info-gen3.h"

/******************************************************************************
 *
 * RX path functions
 *
 ******************************************************************************/

/*
 * Rx theory of operation
 *
 * Driver allocates a circular buffer of Receive Buffer Descriptors (RBDs),
 * each of which point to Receive Buffers to be filled by the NIC.  These get
 * used not only for Rx frames, but for any command response or notification
 * from the NIC.  The driver and NIC manage the Rx buffers by means
 * of indexes into the circular buffer.
 *
 * Rx Queue Indexes
 * The host/firmware share two index registers for managing the Rx buffers.
 *
 * The READ index maps to the first position that the firmware may be writing
 * to -- the driver can read up to (but not including) this position and get
 * good data.
 * The READ index is managed by the firmware once the card is enabled.
 *
 * The WRITE index maps to the last position the driver has read from -- the
 * position preceding WRITE is the last slot the firmware can place a packet.
 *
 * The queue is empty (no good data) if WRITE = READ - 1, and is full if
 * WRITE = READ.
 *
 * During initialization, the host sets up the READ queue position to the first
 * INDEX position, and WRITE to the last (READ - 1 wrapped)
 *
 * When the firmware places a packet in a buffer, it will advance the READ index
 * and fire the RX interrupt.  The driver can then query the READ index and
 * process as many packets as possible, moving the WRITE index forward as it
 * resets the Rx queue buffers with new memory.
 *
 * The management in the driver is as follows:
 * + A list of pre-allocated RBDs is stored in iwl->rxq->rx_free.
 *   When the interrupt handler is called, the request is processed.
 *   The page is either stolen - transferred to the upper layer
 *   or reused - added immediately to the iwl->rxq->rx_free list.
 * + When the page is stolen - the driver updates the matching queue's used
 *   count, detaches the RBD and transfers it to the queue used list.
 *   When there are two used RBDs - they are transferred to the allocator empty
 *   list. Work is then scheduled for the allocator to start allocating
 *   eight buffers.
 *   When there are another 6 used RBDs - they are transferred to the allocator
 *   empty list and the driver tries to claim the pre-allocated buffers and
 *   add them to iwl->rxq->rx_free. If it fails - it continues to claim them
 *   until ready.
 *   When there are 8+ buffers in the free list - either from allocation or from
 *   8 reused unstolen pages - restock is called to update the FW and indexes.
 * + In order to make sure the allocator always has RBDs to use for allocation
 *   the allocator has initial pool in the size of num_queues*(8-2) - the
 *   maximum missing RBDs per allocation request (request posted with 2
 *    empty RBDs, there is no guarantee when the other 6 RBDs are supplied).
 *   The queues supplies the recycle of the rest of the RBDs.
 * + A received packet is processed and handed to the kernel network stack,
 *   detached from the iwl->rxq.  The driver 'processed' index is updated.
 * + If there are no allocated buffers in iwl->rxq->rx_free,
 *   the READ INDEX is not incremented and iwl->status(RX_STALLED) is set.
 *   If there were enough free buffers and RX_STALLED is set it is cleared.
 *
 *
 * Driver sequence:
 *
 * iwl_rxq_alloc()            Allocates rx_free
 * iwl_pcie_rx_replenish()    Replenishes rx_free list from rx_used, and calls
 *                            iwl_pcie_rxq_restock.
 *                            Used only during initialization.
 * iwl_pcie_rxq_restock()     Moves available buffers from rx_free into Rx
 *                            queue, updates firmware pointers, and updates
 *                            the WRITE index.
 * iwl_pcie_rx_allocator()     Background work for allocating pages.
 *
 * -- enable interrupts --
 * ISR - iwl_rx()             Detach iwl_rx_mem_buffers from pool up to the
 *                            READ INDEX, detaching the SKB from the pool.
 *                            Moves the packet buffer from queue to rx_used.
 *                            Posts and claims requests to the allocator.
 *                            Calls iwl_pcie_rxq_restock to refill any empty
 *                            slots.
 *
 * RBD life-cycle:
 *
 * Init:
 * rxq.pool -> rxq.rx_used -> rxq.rx_free -> rxq.queue
 *
 * Regular Receive interrupt:
 * Page Stolen:
 * rxq.queue -> rxq.rx_used -> allocator.rbd_empty ->
 * allocator.rbd_allocated -> rxq.rx_free -> rxq.queue
 * Page not Stolen:
 * rxq.queue -> rxq.rx_free -> rxq.queue
 * ...
 *
 */

/*
 * iwl_rxq_space - Return number of free slots available in queue.
 */
static int iwl_rxq_space(const struct iwl_rxq *rxq)
{
        /* Make sure rx queue size is a power of 2 */
        WARN_ON(rxq->queue_size & (rxq->queue_size - 1));

        /*
         * There can be up to (RX_QUEUE_SIZE - 1) free slots, to avoid ambiguity
         * between empty and completely full queues.
         * The following is equivalent to modulo by RX_QUEUE_SIZE and is well
         * defined for negative dividends.
         */
        return (rxq->read - rxq->write - 1) & (rxq->queue_size - 1);
}

/*
 * iwl_dma_addr2rbd_ptr - convert a DMA address to a uCode read buffer ptr
 */
static inline __le32 iwl_pcie_dma_addr2rbd_ptr(dma_addr_t dma_addr)
{
        return cpu_to_le32((u32)(dma_addr >> 8));
}

/*
 * iwl_pcie_rx_stop - stops the Rx DMA
 */
int iwl_pcie_rx_stop(struct iwl_trans *trans)
{
        if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210) {
                /* TODO: remove this once fw does it */
                iwl_write_umac_prph(trans, RFH_RXF_DMA_CFG_GEN3, 0);
                return iwl_poll_umac_prph_bit(trans, RFH_GEN_STATUS_GEN3,
                                              RXF_DMA_IDLE, RXF_DMA_IDLE, 1000);
        } else if (trans->trans_cfg->mq_rx_supported) {
                iwl_write_prph(trans, RFH_RXF_DMA_CFG, 0);
                return iwl_poll_prph_bit(trans, RFH_GEN_STATUS,
                                           RXF_DMA_IDLE, RXF_DMA_IDLE, 1000);
        } else {
                iwl_write_direct32(trans, FH_MEM_RCSR_CHNL0_CONFIG_REG, 0);
                return iwl_poll_direct_bit(trans, FH_MEM_RSSR_RX_STATUS_REG,
                                           FH_RSSR_CHNL0_RX_STATUS_CHNL_IDLE,
                                           1000);
        }
}

/*
 * iwl_pcie_rxq_inc_wr_ptr - Update the write pointer for the RX queue
 */
static void iwl_pcie_rxq_inc_wr_ptr(struct iwl_trans *trans,
                                    struct iwl_rxq *rxq)
{
        u32 reg;

        lockdep_assert_held(&rxq->lock);

        /*
         * explicitly wake up the NIC if:
         * 1. shadow registers aren't enabled
         * 2. there is a chance that the NIC is asleep
         */
        if (!trans->trans_cfg->base_params->shadow_reg_enable &&
            test_bit(STATUS_TPOWER_PMI, &trans->status)) {
                reg = iwl_read32(trans, CSR_UCODE_DRV_GP1);

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

        rxq->write_actual = round_down(rxq->write, 8);
        if (trans->trans_cfg->mq_rx_supported)
                iwl_write32(trans, RFH_Q_FRBDCB_WIDX_TRG(rxq->id),
                            rxq->write_actual);
        else
                iwl_write32(trans, FH_RSCSR_CHNL0_WPTR, rxq->write_actual);
}

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

        for (i = 0; i < trans->num_rx_queues; i++) {
                struct iwl_rxq *rxq = &trans_pcie->rxq[i];

                if (!rxq->need_update)
                        continue;
                spin_lock_bh(&rxq->lock);
                iwl_pcie_rxq_inc_wr_ptr(trans, rxq);
                rxq->need_update = false;
                spin_unlock_bh(&rxq->lock);
        }
}

static void iwl_pcie_restock_bd(struct iwl_trans *trans,
                                struct iwl_rxq *rxq,
                                struct iwl_rx_mem_buffer *rxb)
{
        if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210) {
                struct iwl_rx_transfer_desc *bd = rxq->bd;

                BUILD_BUG_ON(sizeof(*bd) != 2 * sizeof(u64));

                bd[rxq->write].addr = cpu_to_le64(rxb->page_dma);
                bd[rxq->write].rbid = cpu_to_le16(rxb->vid);
        } else {
                __le64 *bd = rxq->bd;

                bd[rxq->write] = cpu_to_le64(rxb->page_dma | rxb->vid);
        }

        IWL_DEBUG_RX(trans, "Assigned virtual RB ID %u to queue %d index %d\n",
                     (u32)rxb->vid, rxq->id, rxq->write);
}

/*
 * iwl_pcie_rxmq_restock - restock implementation for multi-queue rx
 */
static void iwl_pcie_rxmq_restock(struct iwl_trans *trans,
                                  struct iwl_rxq *rxq)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rx_mem_buffer *rxb;

        /*
         * If the device isn't enabled - no need to try to add buffers...
         * This can happen when we stop the device and still have an interrupt
         * pending. We stop the APM before we sync the interrupts because we
         * have to (see comment there). On the other hand, since the APM is
         * stopped, we cannot access the HW (in particular not prph).
         * So don't try to restock if the APM has been already stopped.
         */
        if (!test_bit(STATUS_DEVICE_ENABLED, &trans->status))
                return;

        spin_lock_bh(&rxq->lock);
        while (rxq->free_count) {
                /* Get next free Rx buffer, remove from free list */
                rxb = list_first_entry(&rxq->rx_free, struct iwl_rx_mem_buffer,
                                       list);
                list_del(&rxb->list);
                rxb->invalid = false;
                /* some low bits are expected to be unset (depending on hw) */
                WARN_ON(rxb->page_dma & trans_pcie->supported_dma_mask);
                /* Point to Rx buffer via next RBD in circular buffer */
                iwl_pcie_restock_bd(trans, rxq, rxb);
                rxq->write = (rxq->write + 1) & (rxq->queue_size - 1);
                rxq->free_count--;
        }
        spin_unlock_bh(&rxq->lock);

        /*
         * If we've added more space for the firmware to place data, tell it.
         * Increment device's write pointer in multiples of 8.
         */
        if (rxq->write_actual != (rxq->write & ~0x7)) {
                spin_lock_bh(&rxq->lock);
                iwl_pcie_rxq_inc_wr_ptr(trans, rxq);
                spin_unlock_bh(&rxq->lock);
        }
}

/*
 * iwl_pcie_rxsq_restock - restock implementation for single queue rx
 */
static void iwl_pcie_rxsq_restock(struct iwl_trans *trans,
                                  struct iwl_rxq *rxq)
{
        struct iwl_rx_mem_buffer *rxb;

        /*
         * If the device isn't enabled - not need to try to add buffers...
         * This can happen when we stop the device and still have an interrupt
         * pending. We stop the APM before we sync the interrupts because we
         * have to (see comment there). On the other hand, since the APM is
         * stopped, we cannot access the HW (in particular not prph).
         * So don't try to restock if the APM has been already stopped.
         */
        if (!test_bit(STATUS_DEVICE_ENABLED, &trans->status))
                return;

        spin_lock(&rxq->lock);
        while ((iwl_rxq_space(rxq) > 0) && (rxq->free_count)) {
                __le32 *bd = (__le32 *)rxq->bd;
                /* The overwritten rxb must be a used one */
                rxb = rxq->queue[rxq->write];
                BUG_ON(rxb && rxb->page);

                /* Get next free Rx buffer, remove from free list */
                rxb = list_first_entry(&rxq->rx_free, struct iwl_rx_mem_buffer,
                                       list);
                list_del(&rxb->list);
                rxb->invalid = false;

                /* Point to Rx buffer via next RBD in circular buffer */
                bd[rxq->write] = iwl_pcie_dma_addr2rbd_ptr(rxb->page_dma);
                rxq->queue[rxq->write] = rxb;
                rxq->write = (rxq->write + 1) & RX_QUEUE_MASK;
                rxq->free_count--;
        }
        spin_unlock(&rxq->lock);

        /* If we've added more space for the firmware to place data, tell it.
         * Increment device's write pointer in multiples of 8. */
        if (rxq->write_actual != (rxq->write & ~0x7)) {
                spin_lock(&rxq->lock);
                iwl_pcie_rxq_inc_wr_ptr(trans, rxq);
                spin_unlock(&rxq->lock);
        }
}

/*
 * iwl_pcie_rxq_restock - refill RX queue from pre-allocated pool
 *
 * If there are slots in the RX queue that need to be restocked,
 * and we have free pre-allocated buffers, fill the ranks as much
 * as we can, pulling from rx_free.
 *
 * This moves the 'write' index forward to catch up with 'processed', and
 * also updates the memory address in the firmware to reference the new
 * target buffer.
 */
static
void iwl_pcie_rxq_restock(struct iwl_trans *trans, struct iwl_rxq *rxq)
{
        if (trans->trans_cfg->mq_rx_supported)
                iwl_pcie_rxmq_restock(trans, rxq);
        else
                iwl_pcie_rxsq_restock(trans, rxq);
}

/*
 * iwl_pcie_rx_alloc_page - allocates and returns a page.
 *
 */
static struct page *iwl_pcie_rx_alloc_page(struct iwl_trans *trans,
                                           u32 *offset, gfp_t priority)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        unsigned int rbsize = iwl_trans_get_rb_size(trans_pcie->rx_buf_size);
        unsigned int allocsize = PAGE_SIZE << trans_pcie->rx_page_order;
        struct page *page;
        gfp_t gfp_mask = priority;

        if (trans_pcie->rx_page_order > 0)
                gfp_mask |= __GFP_COMP;

        if (trans_pcie->alloc_page) {
                spin_lock_bh(&trans_pcie->alloc_page_lock);
                /* recheck */
                if (trans_pcie->alloc_page) {
                        *offset = trans_pcie->alloc_page_used;
                        page = trans_pcie->alloc_page;
                        trans_pcie->alloc_page_used += rbsize;
                        if (trans_pcie->alloc_page_used >= allocsize)
                                trans_pcie->alloc_page = NULL;
                        else
                                get_page(page);
                        spin_unlock_bh(&trans_pcie->alloc_page_lock);
                        return page;
                }
                spin_unlock_bh(&trans_pcie->alloc_page_lock);
        }

        /* Alloc a new receive buffer */
        page = alloc_pages(gfp_mask, trans_pcie->rx_page_order);
        if (!page) {
                if (net_ratelimit())
                        IWL_DEBUG_INFO(trans, "alloc_pages failed, order: %d\n",
                                       trans_pcie->rx_page_order);
                /*
                 * Issue an error if we don't have enough pre-allocated
                  * buffers.
                 */
                if (!(gfp_mask & __GFP_NOWARN) && net_ratelimit())
                        IWL_CRIT(trans,
                                 "Failed to alloc_pages\n");
                return NULL;
        }

        if (2 * rbsize <= allocsize) {
                spin_lock_bh(&trans_pcie->alloc_page_lock);
                if (!trans_pcie->alloc_page) {
                        get_page(page);
                        trans_pcie->alloc_page = page;
                        trans_pcie->alloc_page_used = rbsize;
                }
                spin_unlock_bh(&trans_pcie->alloc_page_lock);
        }

        *offset = 0;
        return page;
}

/*
 * iwl_pcie_rxq_alloc_rbs - allocate a page for each used RBD
 *
 * A used RBD is an Rx buffer that has been given to the stack. To use it again
 * a page must be allocated and the RBD must point to the page. This function
 * doesn't change the HW pointer but handles the list of pages that is used by
 * iwl_pcie_rxq_restock. The latter function will update the HW to use the newly
 * allocated buffers.
 */
void iwl_pcie_rxq_alloc_rbs(struct iwl_trans *trans, gfp_t priority,
                            struct iwl_rxq *rxq)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rx_mem_buffer *rxb;
        struct page *page;

        while (1) {
                unsigned int offset;

                spin_lock(&rxq->lock);
                if (list_empty(&rxq->rx_used)) {
                        spin_unlock(&rxq->lock);
                        return;
                }
                spin_unlock(&rxq->lock);

                page = iwl_pcie_rx_alloc_page(trans, &offset, priority);
                if (!page)
                        return;

                spin_lock(&rxq->lock);

                if (list_empty(&rxq->rx_used)) {
                        spin_unlock(&rxq->lock);
                        __free_pages(page, trans_pcie->rx_page_order);
                        return;
                }
                rxb = list_first_entry(&rxq->rx_used, struct iwl_rx_mem_buffer,
                                       list);
                list_del(&rxb->list);
                spin_unlock(&rxq->lock);

                BUG_ON(rxb->page);
                rxb->page = page;
                rxb->offset = offset;
                /* Get physical address of the RB */
                rxb->page_dma =
                        dma_map_page(trans->dev, page, rxb->offset,
                                     trans_pcie->rx_buf_bytes,
                                     DMA_FROM_DEVICE);
                if (dma_mapping_error(trans->dev, rxb->page_dma)) {
                        rxb->page = NULL;
                        spin_lock(&rxq->lock);
                        list_add(&rxb->list, &rxq->rx_used);
                        spin_unlock(&rxq->lock);
                        __free_pages(page, trans_pcie->rx_page_order);
                        return;
                }

                spin_lock(&rxq->lock);

                list_add_tail(&rxb->list, &rxq->rx_free);
                rxq->free_count++;

                spin_unlock(&rxq->lock);
        }
}

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

        for (i = 0; i < RX_POOL_SIZE(trans_pcie->num_rx_bufs); i++) {
                if (!trans_pcie->rx_pool[i].page)
                        continue;
                dma_unmap_page(trans->dev, trans_pcie->rx_pool[i].page_dma,
                               trans_pcie->rx_buf_bytes, DMA_FROM_DEVICE);
                __free_pages(trans_pcie->rx_pool[i].page,
                             trans_pcie->rx_page_order);
                trans_pcie->rx_pool[i].page = NULL;
        }
}

/*
 * iwl_pcie_rx_allocator - Allocates pages in the background for RX queues
 *
 * Allocates for each received request 8 pages
 * Called as a scheduled work item.
 */
static void iwl_pcie_rx_allocator(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rb_allocator *rba = &trans_pcie->rba;
        struct list_head local_empty;
        int pending = atomic_read(&rba->req_pending);

        IWL_DEBUG_TPT(trans, "Pending allocation requests = %d\n", pending);

        /* If we were scheduled - there is at least one request */
        spin_lock_bh(&rba->lock);
        /* swap out the rba->rbd_empty to a local list */
        list_replace_init(&rba->rbd_empty, &local_empty);
        spin_unlock_bh(&rba->lock);

        while (pending) {
                int i;
                LIST_HEAD(local_allocated);
                gfp_t gfp_mask = GFP_KERNEL;

                /* Do not post a warning if there are only a few requests */
                if (pending < RX_PENDING_WATERMARK)
                        gfp_mask |= __GFP_NOWARN;

                for (i = 0; i < RX_CLAIM_REQ_ALLOC;) {
                        struct iwl_rx_mem_buffer *rxb;
                        struct page *page;

                        /* List should never be empty - each reused RBD is
                         * returned to the list, and initial pool covers any
                         * possible gap between the time the page is allocated
                         * to the time the RBD is added.
                         */
                        BUG_ON(list_empty(&local_empty));
                        /* Get the first rxb from the rbd list */
                        rxb = list_first_entry(&local_empty,
                                               struct iwl_rx_mem_buffer, list);
                        BUG_ON(rxb->page);

                        /* Alloc a new receive buffer */
                        page = iwl_pcie_rx_alloc_page(trans, &rxb->offset,
                                                      gfp_mask);
                        if (!page)
                                continue;
                        rxb->page = page;

                        /* Get physical address of the RB */
                        rxb->page_dma = dma_map_page(trans->dev, page,
                                                     rxb->offset,
                                                     trans_pcie->rx_buf_bytes,
                                                     DMA_FROM_DEVICE);
                        if (dma_mapping_error(trans->dev, rxb->page_dma)) {
                                rxb->page = NULL;
                                __free_pages(page, trans_pcie->rx_page_order);
                                continue;
                        }

                        /* move the allocated entry to the out list */
                        list_move(&rxb->list, &local_allocated);
                        i++;
                }

                atomic_dec(&rba->req_pending);
                pending--;

                if (!pending) {
                        pending = atomic_read(&rba->req_pending);
                        if (pending)
                                IWL_DEBUG_TPT(trans,
                                              "Got more pending allocation requests = %d\n",
                                              pending);
                }

                spin_lock_bh(&rba->lock);
                /* add the allocated rbds to the allocator allocated list */
                list_splice_tail(&local_allocated, &rba->rbd_allocated);
                /* get more empty RBDs for current pending requests */
                list_splice_tail_init(&rba->rbd_empty, &local_empty);
                spin_unlock_bh(&rba->lock);

                atomic_inc(&rba->req_ready);

        }

        spin_lock_bh(&rba->lock);
        /* return unused rbds to the allocator empty list */
        list_splice_tail(&local_empty, &rba->rbd_empty);
        spin_unlock_bh(&rba->lock);

        IWL_DEBUG_TPT(trans, "%s, exit.\n", __func__);
}

/*
 * iwl_pcie_rx_allocator_get - returns the pre-allocated pages
.*
.* Called by queue when the queue posted allocation request and
 * has freed 8 RBDs in order to restock itself.
 * This function directly moves the allocated RBs to the queue's ownership
 * and updates the relevant counters.
 */
static void iwl_pcie_rx_allocator_get(struct iwl_trans *trans,
                                      struct iwl_rxq *rxq)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rb_allocator *rba = &trans_pcie->rba;
        int i;

        lockdep_assert_held(&rxq->lock);

        /*
         * atomic_dec_if_positive returns req_ready - 1 for any scenario.
         * If req_ready is 0 atomic_dec_if_positive will return -1 and this
         * function will return early, as there are no ready requests.
         * atomic_dec_if_positive will perofrm the *actual* decrement only if
         * req_ready > 0, i.e. - there are ready requests and the function
         * hands one request to the caller.
         */
        if (atomic_dec_if_positive(&rba->req_ready) < 0)
                return;

        spin_lock(&rba->lock);
        for (i = 0; i < RX_CLAIM_REQ_ALLOC; i++) {
                /* Get next free Rx buffer, remove it from free list */
                struct iwl_rx_mem_buffer *rxb =
                        list_first_entry(&rba->rbd_allocated,
                                         struct iwl_rx_mem_buffer, list);

                list_move(&rxb->list, &rxq->rx_free);
        }
        spin_unlock(&rba->lock);

        rxq->used_count -= RX_CLAIM_REQ_ALLOC;
        rxq->free_count += RX_CLAIM_REQ_ALLOC;
}

void iwl_pcie_rx_allocator_work(struct work_struct *data)
{
        struct iwl_rb_allocator *rba_p =
                container_of(data, struct iwl_rb_allocator, rx_alloc);
        struct iwl_trans_pcie *trans_pcie =
                container_of(rba_p, struct iwl_trans_pcie, rba);

        iwl_pcie_rx_allocator(trans_pcie->trans);
}

static int iwl_pcie_free_bd_size(struct iwl_trans *trans, bool use_rx_td)
{
        struct iwl_rx_transfer_desc *rx_td;

        if (use_rx_td)
                return sizeof(*rx_td);
        else
                return trans->trans_cfg->mq_rx_supported ? sizeof(__le64) :
                        sizeof(__le32);
}

static void iwl_pcie_free_rxq_dma(struct iwl_trans *trans,
                                  struct iwl_rxq *rxq)
{
        struct device *dev = trans->dev;
        bool use_rx_td = (trans->trans_cfg->device_family >=
                          IWL_DEVICE_FAMILY_AX210);
        int free_size = iwl_pcie_free_bd_size(trans, use_rx_td);

        if (rxq->bd)
                dma_free_coherent(trans->dev,
                                  free_size * rxq->queue_size,
                                  rxq->bd, rxq->bd_dma);
        rxq->bd_dma = 0;
        rxq->bd = NULL;

        rxq->rb_stts_dma = 0;
        rxq->rb_stts = NULL;

        if (rxq->used_bd)
                dma_free_coherent(trans->dev,
                                  (use_rx_td ? sizeof(*rxq->cd) :
                                   sizeof(__le32)) * rxq->queue_size,
                                  rxq->used_bd, rxq->used_bd_dma);
        rxq->used_bd_dma = 0;
        rxq->used_bd = NULL;

        if (trans->trans_cfg->device_family < IWL_DEVICE_FAMILY_AX210)
                return;

        if (rxq->tr_tail)
                dma_free_coherent(dev, sizeof(__le16),
                                  rxq->tr_tail, rxq->tr_tail_dma);
        rxq->tr_tail_dma = 0;
        rxq->tr_tail = NULL;

        if (rxq->cr_tail)
                dma_free_coherent(dev, sizeof(__le16),
                                  rxq->cr_tail, rxq->cr_tail_dma);
        rxq->cr_tail_dma = 0;
        rxq->cr_tail = NULL;
}

static int iwl_pcie_alloc_rxq_dma(struct iwl_trans *trans,
                                  struct iwl_rxq *rxq)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct device *dev = trans->dev;
        int i;
        int free_size;
        bool use_rx_td = (trans->trans_cfg->device_family >=
                          IWL_DEVICE_FAMILY_AX210);
        size_t rb_stts_size = use_rx_td ? sizeof(__le16) :
                              sizeof(struct iwl_rb_status);

        spin_lock_init(&rxq->lock);
        if (trans->trans_cfg->mq_rx_supported)
                rxq->queue_size = trans->cfg->num_rbds;
        else
                rxq->queue_size = RX_QUEUE_SIZE;

        free_size = iwl_pcie_free_bd_size(trans, use_rx_td);

        /*
         * Allocate the circular buffer of Read Buffer Descriptors
         * (RBDs)
         */
        rxq->bd = dma_alloc_coherent(dev, free_size * rxq->queue_size,
                                     &rxq->bd_dma, GFP_KERNEL);
        if (!rxq->bd)
                goto err;

        if (trans->trans_cfg->mq_rx_supported) {
                rxq->used_bd = dma_alloc_coherent(dev,
                                                  (use_rx_td ? sizeof(*rxq->cd) : sizeof(__le32)) * rxq->queue_size,
                                                  &rxq->used_bd_dma,
                                                  GFP_KERNEL);
                if (!rxq->used_bd)
                        goto err;
        }

        rxq->rb_stts = trans_pcie->base_rb_stts + rxq->id * rb_stts_size;
        rxq->rb_stts_dma =
                trans_pcie->base_rb_stts_dma + rxq->id * rb_stts_size;

        if (!use_rx_td)
                return 0;

        /* Allocate the driver's pointer to TR tail */
        rxq->tr_tail = dma_alloc_coherent(dev, sizeof(__le16),
                                          &rxq->tr_tail_dma, GFP_KERNEL);
        if (!rxq->tr_tail)
                goto err;

        /* Allocate the driver's pointer to CR tail */
        rxq->cr_tail = dma_alloc_coherent(dev, sizeof(__le16),
                                          &rxq->cr_tail_dma, GFP_KERNEL);
        if (!rxq->cr_tail)
                goto err;

        return 0;

err:
        for (i = 0; i < trans->num_rx_queues; i++) {
                struct iwl_rxq *rxq = &trans_pcie->rxq[i];

                iwl_pcie_free_rxq_dma(trans, rxq);
        }

        return -ENOMEM;
}

static int iwl_pcie_rx_alloc(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rb_allocator *rba = &trans_pcie->rba;
        int i, ret;
        size_t rb_stts_size = trans->trans_cfg->device_family >=
                                IWL_DEVICE_FAMILY_AX210 ?
                              sizeof(__le16) : sizeof(struct iwl_rb_status);

        if (WARN_ON(trans_pcie->rxq))
                return -EINVAL;

        trans_pcie->rxq = kcalloc(trans->num_rx_queues, sizeof(struct iwl_rxq),
                                  GFP_KERNEL);
        trans_pcie->rx_pool = kcalloc(RX_POOL_SIZE(trans_pcie->num_rx_bufs),
                                      sizeof(trans_pcie->rx_pool[0]),
                                      GFP_KERNEL);
        trans_pcie->global_table =
                kcalloc(RX_POOL_SIZE(trans_pcie->num_rx_bufs),
                        sizeof(trans_pcie->global_table[0]),
                        GFP_KERNEL);
        if (!trans_pcie->rxq || !trans_pcie->rx_pool ||
            !trans_pcie->global_table) {
                ret = -ENOMEM;
                goto err;
        }

        spin_lock_init(&rba->lock);

        /*
         * Allocate the driver's pointer to receive buffer status.
         * Allocate for all queues continuously (HW requirement).
         */
        trans_pcie->base_rb_stts =
                        dma_alloc_coherent(trans->dev,
                                           rb_stts_size * trans->num_rx_queues,
                                           &trans_pcie->base_rb_stts_dma,
                                           GFP_KERNEL);
        if (!trans_pcie->base_rb_stts) {
                ret = -ENOMEM;
                goto err;
        }

        for (i = 0; i < trans->num_rx_queues; i++) {
                struct iwl_rxq *rxq = &trans_pcie->rxq[i];

                rxq->id = i;
                ret = iwl_pcie_alloc_rxq_dma(trans, rxq);
                if (ret)
                        goto err;
        }
        return 0;

err:
        if (trans_pcie->base_rb_stts) {
                dma_free_coherent(trans->dev,
                                  rb_stts_size * trans->num_rx_queues,
                                  trans_pcie->base_rb_stts,
                                  trans_pcie->base_rb_stts_dma);
                trans_pcie->base_rb_stts = NULL;
                trans_pcie->base_rb_stts_dma = 0;
        }
        kfree(trans_pcie->rx_pool);
        kfree(trans_pcie->global_table);
        kfree(trans_pcie->rxq);

        return ret;
}

static void iwl_pcie_rx_hw_init(struct iwl_trans *trans, struct iwl_rxq *rxq)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 rb_size;
        unsigned long flags;
        const u32 rfdnlog = RX_QUEUE_SIZE_LOG; /* 256 RBDs */

        switch (trans_pcie->rx_buf_size) {
        case IWL_AMSDU_4K:
                rb_size = FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_4K;
                break;
        case IWL_AMSDU_8K:
                rb_size = FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_8K;
                break;
        case IWL_AMSDU_12K:
                rb_size = FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_12K;
                break;
        default:
                WARN_ON(1);
                rb_size = FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_4K;
        }

        if (!iwl_trans_grab_nic_access(trans, &flags))
                return;

        /* Stop Rx DMA */
        iwl_write32(trans, FH_MEM_RCSR_CHNL0_CONFIG_REG, 0);
        /* reset and flush pointers */
        iwl_write32(trans, FH_MEM_RCSR_CHNL0_RBDCB_WPTR, 0);
        iwl_write32(trans, FH_MEM_RCSR_CHNL0_FLUSH_RB_REQ, 0);
        iwl_write32(trans, FH_RSCSR_CHNL0_RDPTR, 0);

        /* Reset driver's Rx queue write index */
        iwl_write32(trans, FH_RSCSR_CHNL0_RBDCB_WPTR_REG, 0);

        /* Tell device where to find RBD circular buffer in DRAM */
        iwl_write32(trans, FH_RSCSR_CHNL0_RBDCB_BASE_REG,
                    (u32)(rxq->bd_dma >> 8));

        /* Tell device where in DRAM to update its Rx status */
        iwl_write32(trans, FH_RSCSR_CHNL0_STTS_WPTR_REG,
                    rxq->rb_stts_dma >> 4);

        /* Enable Rx DMA
         * FH_RCSR_CHNL0_RX_IGNORE_RXF_EMPTY is set because of HW bug in
         *      the credit mechanism in 5000 HW RX FIFO
         * Direct rx interrupts to hosts
         * Rx buffer size 4 or 8k or 12k
         * RB timeout 0x10
         * 256 RBDs
         */
        iwl_write32(trans, FH_MEM_RCSR_CHNL0_CONFIG_REG,
                    FH_RCSR_RX_CONFIG_CHNL_EN_ENABLE_VAL |
                    FH_RCSR_CHNL0_RX_IGNORE_RXF_EMPTY |
                    FH_RCSR_CHNL0_RX_CONFIG_IRQ_DEST_INT_HOST_VAL |
                    rb_size |
                    (RX_RB_TIMEOUT << FH_RCSR_RX_CONFIG_REG_IRQ_RBTH_POS) |
                    (rfdnlog << FH_RCSR_RX_CONFIG_RBDCB_SIZE_POS));

        iwl_trans_release_nic_access(trans, &flags);

        /* Set interrupt coalescing timer to default (2048 usecs) */
        iwl_write8(trans, CSR_INT_COALESCING, IWL_HOST_INT_TIMEOUT_DEF);

        /* W/A for interrupt coalescing bug in 7260 and 3160 */
        if (trans->cfg->host_interrupt_operation_mode)
                iwl_set_bit(trans, CSR_INT_COALESCING, IWL_HOST_INT_OPER_MODE);
}

static void iwl_pcie_rx_mq_hw_init(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 rb_size, enabled = 0;
        unsigned long flags;
        int i;

        switch (trans_pcie->rx_buf_size) {
        case IWL_AMSDU_2K:
                rb_size = RFH_RXF_DMA_RB_SIZE_2K;
                break;
        case IWL_AMSDU_4K:
                rb_size = RFH_RXF_DMA_RB_SIZE_4K;
                break;
        case IWL_AMSDU_8K:
                rb_size = RFH_RXF_DMA_RB_SIZE_8K;
                break;
        case IWL_AMSDU_12K:
                rb_size = RFH_RXF_DMA_RB_SIZE_12K;
                break;
        default:
                WARN_ON(1);
                rb_size = RFH_RXF_DMA_RB_SIZE_4K;
        }

        if (!iwl_trans_grab_nic_access(trans, &flags))
                return;

        /* Stop Rx DMA */
        iwl_write_prph_no_grab(trans, RFH_RXF_DMA_CFG, 0);
        /* disable free amd used rx queue operation */
        iwl_write_prph_no_grab(trans, RFH_RXF_RXQ_ACTIVE, 0);

        for (i = 0; i < trans->num_rx_queues; i++) {
                /* Tell device where to find RBD free table in DRAM */
                iwl_write_prph64_no_grab(trans,
                                         RFH_Q_FRBDCB_BA_LSB(i),
                                         trans_pcie->rxq[i].bd_dma);
                /* Tell device where to find RBD used table in DRAM */
                iwl_write_prph64_no_grab(trans,
                                         RFH_Q_URBDCB_BA_LSB(i),
                                         trans_pcie->rxq[i].used_bd_dma);
                /* Tell device where in DRAM to update its Rx status */
                iwl_write_prph64_no_grab(trans,
                                         RFH_Q_URBD_STTS_WPTR_LSB(i),
                                         trans_pcie->rxq[i].rb_stts_dma);
                /* Reset device indice tables */
                iwl_write_prph_no_grab(trans, RFH_Q_FRBDCB_WIDX(i), 0);
                iwl_write_prph_no_grab(trans, RFH_Q_FRBDCB_RIDX(i), 0);
                iwl_write_prph_no_grab(trans, RFH_Q_URBDCB_WIDX(i), 0);

                enabled |= BIT(i) | BIT(i + 16);
        }

        /*
         * Enable Rx DMA
         * Rx buffer size 4 or 8k or 12k
         * Min RB size 4 or 8
         * Drop frames that exceed RB size
         * 512 RBDs
         */
        iwl_write_prph_no_grab(trans, RFH_RXF_DMA_CFG,
                               RFH_DMA_EN_ENABLE_VAL | rb_size |
                               RFH_RXF_DMA_MIN_RB_4_8 |
                               RFH_RXF_DMA_DROP_TOO_LARGE_MASK |
                               RFH_RXF_DMA_RBDCB_SIZE_512);

        /*
         * Activate DMA snooping.
         * Set RX DMA chunk size to 64B for IOSF and 128B for PCIe
         * Default queue is 0
         */
        iwl_write_prph_no_grab(trans, RFH_GEN_CFG,
                               RFH_GEN_CFG_RFH_DMA_SNOOP |
                               RFH_GEN_CFG_VAL(DEFAULT_RXQ_NUM, 0) |
                               RFH_GEN_CFG_SERVICE_DMA_SNOOP |
                               RFH_GEN_CFG_VAL(RB_CHUNK_SIZE,
                                               trans->trans_cfg->integrated ?
                                               RFH_GEN_CFG_RB_CHUNK_SIZE_64 :
                                               RFH_GEN_CFG_RB_CHUNK_SIZE_128));
        /* Enable the relevant rx queues */
        iwl_write_prph_no_grab(trans, RFH_RXF_RXQ_ACTIVE, enabled);

        iwl_trans_release_nic_access(trans, &flags);

        /* Set interrupt coalescing timer to default (2048 usecs) */
        iwl_write8(trans, CSR_INT_COALESCING, IWL_HOST_INT_TIMEOUT_DEF);
}

void iwl_pcie_rx_init_rxb_lists(struct iwl_rxq *rxq)
{
        lockdep_assert_held(&rxq->lock);

        INIT_LIST_HEAD(&rxq->rx_free);
        INIT_LIST_HEAD(&rxq->rx_used);
        rxq->free_count = 0;
        rxq->used_count = 0;
}

static int iwl_pcie_rx_handle(struct iwl_trans *trans, int queue, int budget);

static int iwl_pcie_napi_poll(struct napi_struct *napi, int budget)
{
        struct iwl_rxq *rxq = container_of(napi, struct iwl_rxq, napi);
        struct iwl_trans_pcie *trans_pcie;
        struct iwl_trans *trans;
        int ret;

        trans_pcie = container_of(napi->dev, struct iwl_trans_pcie, napi_dev);
        trans = trans_pcie->trans;

        ret = iwl_pcie_rx_handle(trans, rxq->id, budget);

        if (ret < budget) {
                spin_lock(&trans_pcie->irq_lock);
                if (test_bit(STATUS_INT_ENABLED, &trans->status))
                        _iwl_enable_interrupts(trans);
                spin_unlock(&trans_pcie->irq_lock);

                napi_complete_done(&rxq->napi, ret);
        }

        return ret;
}

static int iwl_pcie_napi_poll_msix(struct napi_struct *napi, int budget)
{
        struct iwl_rxq *rxq = container_of(napi, struct iwl_rxq, napi);
        struct iwl_trans_pcie *trans_pcie;
        struct iwl_trans *trans;
        int ret;

        trans_pcie = container_of(napi->dev, struct iwl_trans_pcie, napi_dev);
        trans = trans_pcie->trans;

        ret = iwl_pcie_rx_handle(trans, rxq->id, budget);

        if (ret < budget) {
                spin_lock(&trans_pcie->irq_lock);
                iwl_pcie_clear_irq(trans, rxq->id);
                spin_unlock(&trans_pcie->irq_lock);

                napi_complete_done(&rxq->napi, ret);
        }

        return ret;
}

static int iwl_pcie_napi_poll_msix_shared(struct napi_struct *napi, int budget)
{
        struct iwl_rxq *rxq = container_of(napi, struct iwl_rxq, napi);
        struct iwl_trans_pcie *trans_pcie;
        struct iwl_trans *trans;
        int ret;

        trans_pcie = container_of(napi->dev, struct iwl_trans_pcie, napi_dev);
        trans = trans_pcie->trans;

        ret = iwl_pcie_rx_handle(trans, rxq->id, budget);

        if (ret < budget) {
                spin_lock(&trans_pcie->irq_lock);
                iwl_pcie_clear_irq(trans, 0);
                spin_unlock(&trans_pcie->irq_lock);

                napi_complete_done(&rxq->napi, ret);
        }

        return ret;
}

static int _iwl_pcie_rx_init(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rxq *def_rxq;
        struct iwl_rb_allocator *rba = &trans_pcie->rba;
        int i, err, queue_size, allocator_pool_size, num_alloc;

        if (!trans_pcie->rxq) {
                err = iwl_pcie_rx_alloc(trans);
                if (err)
                        return err;
        }
        def_rxq = trans_pcie->rxq;

        cancel_work_sync(&rba->rx_alloc);

        spin_lock_bh(&rba->lock);
        atomic_set(&rba->req_pending, 0);
        atomic_set(&rba->req_ready, 0);
        INIT_LIST_HEAD(&rba->rbd_allocated);
        INIT_LIST_HEAD(&rba->rbd_empty);
        spin_unlock_bh(&rba->lock);

        /* free all first - we might be reconfigured for a different size */
        iwl_pcie_free_rbs_pool(trans);

        for (i = 0; i < RX_QUEUE_SIZE; i++)
                def_rxq->queue[i] = NULL;

        for (i = 0; i < trans->num_rx_queues; i++) {
                struct iwl_rxq *rxq = &trans_pcie->rxq[i];

                spin_lock(&rxq->lock);
                /*
                 * Set read write pointer to reflect that we have processed
                 * and used all buffers, but have not restocked the Rx queue
                 * with fresh buffers
                 */
                rxq->read = 0;
                rxq->write = 0;
                rxq->write_actual = 0;
                memset(rxq->rb_stts, 0,
                       (trans->trans_cfg->device_family >=
                        IWL_DEVICE_FAMILY_AX210) ?
                       sizeof(__le16) : sizeof(struct iwl_rb_status));

                iwl_pcie_rx_init_rxb_lists(rxq);

                if (!rxq->napi.poll) {
                        int (*poll)(struct napi_struct *, int) = iwl_pcie_napi_poll;

                        if (trans_pcie->msix_enabled) {
                                poll = iwl_pcie_napi_poll_msix;

                                if (trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_NON_RX &&
                                    i == 0)
                                        poll = iwl_pcie_napi_poll_msix_shared;

                                if (trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_FIRST_RSS &&
                                    i == 1)
                                        poll = iwl_pcie_napi_poll_msix_shared;
                        }

                        netif_napi_add(&trans_pcie->napi_dev, &rxq->napi,
                                       poll, NAPI_POLL_WEIGHT);
                        napi_enable(&rxq->napi);
                }

                spin_unlock(&rxq->lock);
        }

        /* move the pool to the default queue and allocator ownerships */
        queue_size = trans->trans_cfg->mq_rx_supported ?
                        trans_pcie->num_rx_bufs - 1 : RX_QUEUE_SIZE;
        allocator_pool_size = trans->num_rx_queues *
                (RX_CLAIM_REQ_ALLOC - RX_POST_REQ_ALLOC);
        num_alloc = queue_size + allocator_pool_size;

        for (i = 0; i < num_alloc; i++) {
                struct iwl_rx_mem_buffer *rxb = &trans_pcie->rx_pool[i];

                if (i < allocator_pool_size)
                        list_add(&rxb->list, &rba->rbd_empty);
                else
                        list_add(&rxb->list, &def_rxq->rx_used);
                trans_pcie->global_table[i] = rxb;
                rxb->vid = (u16)(i + 1);
                rxb->invalid = true;
        }

        iwl_pcie_rxq_alloc_rbs(trans, GFP_KERNEL, def_rxq);

        return 0;
}

int iwl_pcie_rx_init(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int ret = _iwl_pcie_rx_init(trans);

        if (ret)
                return ret;

        if (trans->trans_cfg->mq_rx_supported)
                iwl_pcie_rx_mq_hw_init(trans);
        else
                iwl_pcie_rx_hw_init(trans, trans_pcie->rxq);

        iwl_pcie_rxq_restock(trans, trans_pcie->rxq);

        spin_lock(&trans_pcie->rxq->lock);
        iwl_pcie_rxq_inc_wr_ptr(trans, trans_pcie->rxq);
        spin_unlock(&trans_pcie->rxq->lock);

        return 0;
}

int iwl_pcie_gen2_rx_init(struct iwl_trans *trans)
{
        /* Set interrupt coalescing timer to default (2048 usecs) */
        iwl_write8(trans, CSR_INT_COALESCING, IWL_HOST_INT_TIMEOUT_DEF);

        /*
         * We don't configure the RFH.
         * Restock will be done at alive, after firmware configured the RFH.
         */
        return _iwl_pcie_rx_init(trans);
}

void iwl_pcie_rx_free(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rb_allocator *rba = &trans_pcie->rba;
        int i;
        size_t rb_stts_size = trans->trans_cfg->device_family >=
                                IWL_DEVICE_FAMILY_AX210 ?
                              sizeof(__le16) : sizeof(struct iwl_rb_status);

        /*
         * if rxq is NULL, it means that nothing has been allocated,
         * exit now
         */
        if (!trans_pcie->rxq) {
                IWL_DEBUG_INFO(trans, "Free NULL rx context\n");
                return;
        }

        cancel_work_sync(&rba->rx_alloc);

        iwl_pcie_free_rbs_pool(trans);

        if (trans_pcie->base_rb_stts) {
                dma_free_coherent(trans->dev,
                                  rb_stts_size * trans->num_rx_queues,
                                  trans_pcie->base_rb_stts,
                                  trans_pcie->base_rb_stts_dma);
                trans_pcie->base_rb_stts = NULL;
                trans_pcie->base_rb_stts_dma = 0;
        }

        for (i = 0; i < trans->num_rx_queues; i++) {
                struct iwl_rxq *rxq = &trans_pcie->rxq[i];

                iwl_pcie_free_rxq_dma(trans, rxq);

                if (rxq->napi.poll) {
                        napi_disable(&rxq->napi);
                        netif_napi_del(&rxq->napi);
                }
        }
        kfree(trans_pcie->rx_pool);
        kfree(trans_pcie->global_table);
        kfree(trans_pcie->rxq);

        if (trans_pcie->alloc_page)
                __free_pages(trans_pcie->alloc_page, trans_pcie->rx_page_order);
}

static void iwl_pcie_rx_move_to_allocator(struct iwl_rxq *rxq,
                                          struct iwl_rb_allocator *rba)
{
        spin_lock(&rba->lock);
        list_splice_tail_init(&rxq->rx_used, &rba->rbd_empty);
        spin_unlock(&rba->lock);
}

/*
 * iwl_pcie_rx_reuse_rbd - Recycle used RBDs
 *
 * Called when a RBD can be reused. The RBD is transferred to the allocator.
 * When there are 2 empty RBDs - a request for allocation is posted
 */
static void iwl_pcie_rx_reuse_rbd(struct iwl_trans *trans,
                                  struct iwl_rx_mem_buffer *rxb,
                                  struct iwl_rxq *rxq, bool emergency)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rb_allocator *rba = &trans_pcie->rba;

        /* Move the RBD to the used list, will be moved to allocator in batches
         * before claiming or posting a request*/
        list_add_tail(&rxb->list, &rxq->rx_used);

        if (unlikely(emergency))
                return;

        /* Count the allocator owned RBDs */
        rxq->used_count++;

        /* If we have RX_POST_REQ_ALLOC new released rx buffers -
         * issue a request for allocator. Modulo RX_CLAIM_REQ_ALLOC is
         * used for the case we failed to claim RX_CLAIM_REQ_ALLOC,
         * after but we still need to post another request.
         */
        if ((rxq->used_count % RX_CLAIM_REQ_ALLOC) == RX_POST_REQ_ALLOC) {
                /* Move the 2 RBDs to the allocator ownership.
                 Allocator has another 6 from pool for the request completion*/
                iwl_pcie_rx_move_to_allocator(rxq, rba);

                atomic_inc(&rba->req_pending);
                queue_work(rba->alloc_wq, &rba->rx_alloc);
        }
}

static void iwl_pcie_rx_handle_rb(struct iwl_trans *trans,
                                struct iwl_rxq *rxq,
                                struct iwl_rx_mem_buffer *rxb,
                                bool emergency,
                                int i)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_txq *txq = trans->txqs.txq[trans->txqs.cmd.q_id];
        bool page_stolen = false;
        int max_len = trans_pcie->rx_buf_bytes;
        u32 offset = 0;

        if (WARN_ON(!rxb))
                return;

        dma_unmap_page(trans->dev, rxb->page_dma, max_len, DMA_FROM_DEVICE);

        while (offset + sizeof(u32) + sizeof(struct iwl_cmd_header) < max_len) {
                struct iwl_rx_packet *pkt;
                bool reclaim;
                int len;
                struct iwl_rx_cmd_buffer rxcb = {
                        ._offset = rxb->offset + offset,
                        ._rx_page_order = trans_pcie->rx_page_order,
                        ._page = rxb->page,
                        ._page_stolen = false,
                        .truesize = max_len,
                };

                pkt = rxb_addr(&rxcb);

                if (pkt->len_n_flags == cpu_to_le32(FH_RSCSR_FRAME_INVALID)) {
                        IWL_DEBUG_RX(trans,
                                     "Q %d: RB end marker at offset %d\n",
                                     rxq->id, offset);
                        break;
                }

                WARN((le32_to_cpu(pkt->len_n_flags) & FH_RSCSR_RXQ_MASK) >>
                        FH_RSCSR_RXQ_POS != rxq->id,
                     "frame on invalid queue - is on %d and indicates %d\n",
                     rxq->id,
                     (le32_to_cpu(pkt->len_n_flags) & FH_RSCSR_RXQ_MASK) >>
                        FH_RSCSR_RXQ_POS);

                IWL_DEBUG_RX(trans,
                             "Q %d: cmd at offset %d: %s (%.2x.%2x, seq 0x%x)\n",
                             rxq->id, offset,
                             iwl_get_cmd_string(trans,
                                                iwl_cmd_id(pkt->hdr.cmd,
                                                           pkt->hdr.group_id,
                                                           0)),
                             pkt->hdr.group_id, pkt->hdr.cmd,
                             le16_to_cpu(pkt->hdr.sequence));

                len = iwl_rx_packet_len(pkt);
                len += sizeof(u32); /* account for status word */

                offset += ALIGN(len, FH_RSCSR_FRAME_ALIGN);

                /* check that what the device tells us made sense */
                if (offset > max_len)
                        break;

                trace_iwlwifi_dev_rx(trans->dev, trans, pkt, len);
                trace_iwlwifi_dev_rx_data(trans->dev, trans, pkt, len);

                /* Reclaim a command buffer only if this packet is a response
                 *   to a (driver-originated) command.
                 * If the packet (e.g. Rx frame) originated from uCode,
                 *   there is no command buffer to reclaim.
                 * Ucode should set SEQ_RX_FRAME bit if ucode-originated,
                 *   but apparently a few don't get set; catch them here. */
                reclaim = !(pkt->hdr.sequence & SEQ_RX_FRAME);
                if (reclaim && !pkt->hdr.group_id) {
                        int i;

                        for (i = 0; i < trans_pcie->n_no_reclaim_cmds; i++) {
                                if (trans_pcie->no_reclaim_cmds[i] ==
                                                        pkt->hdr.cmd) {
                                        reclaim = false;
                                        break;
                                }
                        }
                }

                if (rxq->id == trans_pcie->def_rx_queue)
                        iwl_op_mode_rx(trans->op_mode, &rxq->napi,
                                       &rxcb);
                else
                        iwl_op_mode_rx_rss(trans->op_mode, &rxq->napi,
                                           &rxcb, rxq->id);

                /*
                 * After here, we should always check rxcb._page_stolen,
                 * if it is true then one of the handlers took the page.
                 */

                if (reclaim) {
                        u16 sequence = le16_to_cpu(pkt->hdr.sequence);
                        int index = SEQ_TO_INDEX(sequence);
                        int cmd_index = iwl_txq_get_cmd_index(txq, index);

                        kfree_sensitive(txq->entries[cmd_index].free_buf);
                        txq->entries[cmd_index].free_buf = NULL;

                        /* Invoke any callbacks, transfer the buffer to caller,
                         * and fire off the (possibly) blocking
                         * iwl_trans_send_cmd()
                         * as we reclaim the driver command queue */
                        if (!rxcb._page_stolen)
                                iwl_pcie_hcmd_complete(trans, &rxcb);
                        else
                                IWL_WARN(trans, "Claim null rxb?\n");
                }

                page_stolen |= rxcb._page_stolen;
                if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210)
                        break;
        }

        /* page was stolen from us -- free our reference */
        if (page_stolen) {
                __free_pages(rxb->page, trans_pcie->rx_page_order);
                rxb->page = NULL;
        }

        /* Reuse the page if possible. For notification packets and
         * SKBs that fail to Rx correctly, add them back into the
         * rx_free list for reuse later. */
        if (rxb->page != NULL) {
                rxb->page_dma =
                        dma_map_page(trans->dev, rxb->page, rxb->offset,
                                     trans_pcie->rx_buf_bytes,
                                     DMA_FROM_DEVICE);
                if (dma_mapping_error(trans->dev, rxb->page_dma)) {
                        /*
                         * free the page(s) as well to not break
                         * the invariant that the items on the used
                         * list have no page(s)
                         */
                        __free_pages(rxb->page, trans_pcie->rx_page_order);
                        rxb->page = NULL;
                        iwl_pcie_rx_reuse_rbd(trans, rxb, rxq, emergency);
                } else {
                        list_add_tail(&rxb->list, &rxq->rx_free);
                        rxq->free_count++;
                }
        } else
                iwl_pcie_rx_reuse_rbd(trans, rxb, rxq, emergency);
}

static struct iwl_rx_mem_buffer *iwl_pcie_get_rxb(struct iwl_trans *trans,
                                                  struct iwl_rxq *rxq, int i,
                                                  bool *join)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rx_mem_buffer *rxb;
        u16 vid;

        BUILD_BUG_ON(sizeof(struct iwl_rx_completion_desc) != 32);

        if (!trans->trans_cfg->mq_rx_supported) {
                rxb = rxq->queue[i];
                rxq->queue[i] = NULL;
                return rxb;
        }

        if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210) {
                vid = le16_to_cpu(rxq->cd[i].rbid);
                *join = rxq->cd[i].flags & IWL_RX_CD_FLAGS_FRAGMENTED;
        } else {
                vid = le32_to_cpu(rxq->bd_32[i]) & 0x0FFF; /* 12-bit VID */
        }

        if (!vid || vid > RX_POOL_SIZE(trans_pcie->num_rx_bufs))
                goto out_err;

        rxb = trans_pcie->global_table[vid - 1];
        if (rxb->invalid)
                goto out_err;

        IWL_DEBUG_RX(trans, "Got virtual RB ID %u\n", (u32)rxb->vid);

        rxb->invalid = true;

        return rxb;

out_err:
        WARN(1, "Invalid rxb from HW %u\n", (u32)vid);
        iwl_force_nmi(trans);
        return NULL;
}

/*
 * iwl_pcie_rx_handle - Main entry function for receiving responses from fw
 */
static int iwl_pcie_rx_handle(struct iwl_trans *trans, int queue, int budget)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct iwl_rxq *rxq;
        u32 r, i, count = 0, handled = 0;
        bool emergency = false;

        if (WARN_ON_ONCE(!trans_pcie->rxq || !trans_pcie->rxq[queue].bd))
                return budget;

        rxq = &trans_pcie->rxq[queue];

restart:
        spin_lock(&rxq->lock);
        /* uCode's read index (stored in shared DRAM) indicates the last Rx
         * buffer that the driver may process (last buffer filled by ucode). */
        r = le16_to_cpu(iwl_get_closed_rb_stts(trans, rxq)) & 0x0FFF;
        i = rxq->read;

        /* W/A 9000 device step A0 wrap-around bug */
        r &= (rxq->queue_size - 1);

        /* Rx interrupt, but nothing sent from uCode */
        if (i == r)
                IWL_DEBUG_RX(trans, "Q %d: HW = SW = %d\n", rxq->id, r);

        while (i != r && ++handled < budget) {
                struct iwl_rb_allocator *rba = &trans_pcie->rba;
                struct iwl_rx_mem_buffer *rxb;
                /* number of RBDs still waiting for page allocation */
                u32 rb_pending_alloc =
                        atomic_read(&trans_pcie->rba.req_pending) *
                        RX_CLAIM_REQ_ALLOC;
                bool join = false;

                if (unlikely(rb_pending_alloc >= rxq->queue_size / 2 &&
                             !emergency)) {
                        iwl_pcie_rx_move_to_allocator(rxq, rba);
                        emergency = true;
                        IWL_DEBUG_TPT(trans,
                                      "RX path is in emergency. Pending allocations %d\n",
                                      rb_pending_alloc);
                }

                IWL_DEBUG_RX(trans, "Q %d: HW = %d, SW = %d\n", rxq->id, r, i);

                rxb = iwl_pcie_get_rxb(trans, rxq, i, &join);
                if (!rxb)
                        goto out;

                if (unlikely(join || rxq->next_rb_is_fragment)) {
                        rxq->next_rb_is_fragment = join;
                        /*
                         * We can only get a multi-RB in the following cases:
                         *  - firmware issue, sending a too big notification
                         *  - sniffer mode with a large A-MSDU
                         *  - large MTU frames (>2k)
                         * since the multi-RB functionality is limited to newer
                         * hardware that cannot put multiple entries into a
                         * single RB.
                         *
                         * Right now, the higher layers aren't set up to deal
                         * with that, so discard all of these.
                         */
                        list_add_tail(&rxb->list, &rxq->rx_free);
                        rxq->free_count++;
                } else {
                        iwl_pcie_rx_handle_rb(trans, rxq, rxb, emergency, i);
                }

                i = (i + 1) & (rxq->queue_size - 1);

                /*
                 * If we have RX_CLAIM_REQ_ALLOC released rx buffers -
                 * try to claim the pre-allocated buffers from the allocator.
                 * If not ready - will try to reclaim next time.
                 * There is no need to reschedule work - allocator exits only
                 * on success
                 */
                if (rxq->used_count >= RX_CLAIM_REQ_ALLOC)
                        iwl_pcie_rx_allocator_get(trans, rxq);

                if (rxq->used_count % RX_CLAIM_REQ_ALLOC == 0 && !emergency) {
                        /* Add the remaining empty RBDs for allocator use */
                        iwl_pcie_rx_move_to_allocator(rxq, rba);
                } else if (emergency) {
                        count++;
                        if (count == 8) {
                                count = 0;
                                if (rb_pending_alloc < rxq->queue_size / 3) {
                                        IWL_DEBUG_TPT(trans,
                                                      "RX path exited emergency. Pending allocations %d\n",
                                                      rb_pending_alloc);
                                        emergency = false;
                                }

                                rxq->read = i;
                                spin_unlock(&rxq->lock);
                                iwl_pcie_rxq_alloc_rbs(trans, GFP_ATOMIC, rxq);
                                iwl_pcie_rxq_restock(trans, rxq);
                                goto restart;
                        }
                }
        }
out:
        /* Backtrack one entry */
        rxq->read = i;
        /* update cr tail with the rxq read pointer */
        if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210)
                *rxq->cr_tail = cpu_to_le16(r);
        spin_unlock(&rxq->lock);

        /*
         * handle a case where in emergency there are some unallocated RBDs.
         * those RBDs are in the used list, but are not tracked by the queue's
         * used_count which counts allocator owned RBDs.
         * unallocated emergency RBDs must be allocated on exit, otherwise
         * when called again the function may not be in emergency mode and
         * they will be handed to the allocator with no tracking in the RBD
         * allocator counters, which will lead to them never being claimed back
         * by the queue.
         * by allocating them here, they are now in the queue free list, and
         * will be restocked by the next call of iwl_pcie_rxq_restock.
         */
        if (unlikely(emergency && count))
                iwl_pcie_rxq_alloc_rbs(trans, GFP_ATOMIC, rxq);

        iwl_pcie_rxq_restock(trans, rxq);

        return handled;
}

static struct iwl_trans_pcie *iwl_pcie_get_trans_pcie(struct msix_entry *entry)
{
        u8 queue = entry->entry;
        struct msix_entry *entries = entry - queue;

        return container_of(entries, struct iwl_trans_pcie, msix_entries[0]);
}

/*
 * iwl_pcie_rx_msix_handle - Main entry function for receiving responses from fw
 * This interrupt handler should be used with RSS queue only.
 */
irqreturn_t iwl_pcie_irq_rx_msix_handler(int irq, void *dev_id)
{
        struct msix_entry *entry = dev_id;
        struct iwl_trans_pcie *trans_pcie = iwl_pcie_get_trans_pcie(entry);
        struct iwl_trans *trans = trans_pcie->trans;
        struct iwl_rxq *rxq = &trans_pcie->rxq[entry->entry];

        trace_iwlwifi_dev_irq_msix(trans->dev, entry, false, 0, 0);

        if (WARN_ON(entry->entry >= trans->num_rx_queues))
                return IRQ_NONE;

        lock_map_acquire(&trans->sync_cmd_lockdep_map);

        local_bh_disable();
        if (napi_schedule_prep(&rxq->napi))
                __napi_schedule(&rxq->napi);
        else
                iwl_pcie_clear_irq(trans, entry->entry);
        local_bh_enable();

        lock_map_release(&trans->sync_cmd_lockdep_map);

        return IRQ_HANDLED;
}

/*
 * iwl_pcie_irq_handle_error - called for HW or SW error interrupt from card
 */
static void iwl_pcie_irq_handle_error(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        int i;

        /* W/A for WiFi/WiMAX coex and WiMAX own the RF */
        if (trans->cfg->internal_wimax_coex &&
            !trans->cfg->apmg_not_supported &&
            (!(iwl_read_prph(trans, APMG_CLK_CTRL_REG) &
                             APMS_CLK_VAL_MRB_FUNC_MODE) ||
             (iwl_read_prph(trans, APMG_PS_CTRL_REG) &
                            APMG_PS_CTRL_VAL_RESET_REQ))) {
                clear_bit(STATUS_SYNC_HCMD_ACTIVE, &trans->status);
                iwl_op_mode_wimax_active(trans->op_mode);
                wake_up(&trans_pcie->wait_command_queue);
                return;
        }

        for (i = 0; i < trans->trans_cfg->base_params->num_of_queues; i++) {
                if (!trans->txqs.txq[i])
                        continue;
                del_timer(&trans->txqs.txq[i]->stuck_timer);
        }

        /* The STATUS_FW_ERROR bit is set in this function. This must happen
         * before we wake up the command caller, to ensure a proper cleanup. */
        iwl_trans_fw_error(trans);

        clear_bit(STATUS_SYNC_HCMD_ACTIVE, &trans->status);
        wake_up(&trans_pcie->wait_command_queue);
}

static u32 iwl_pcie_int_cause_non_ict(struct iwl_trans *trans)
{
        u32 inta;

        lockdep_assert_held(&IWL_TRANS_GET_PCIE_TRANS(trans)->irq_lock);

        trace_iwlwifi_dev_irq(trans->dev);

        /* Discover which interrupts are active/pending */
        inta = iwl_read32(trans, CSR_INT);

        /* the thread will service interrupts and re-enable them */
        return inta;
}

/* a device (PCI-E) page is 4096 bytes long */
#define ICT_SHIFT       12
#define ICT_SIZE        (1 << ICT_SHIFT)
#define ICT_COUNT       (ICT_SIZE / sizeof(u32))

/* interrupt handler using ict table, with this interrupt driver will
 * stop using INTA register to get device's interrupt, reading this register
 * is expensive, device will write interrupts in ICT dram table, increment
 * index then will fire interrupt to driver, driver will OR all ICT table
 * entries from current index up to table entry with 0 value. the result is
 * the interrupt we need to service, driver will set the entries back to 0 and
 * set index.
 */
static u32 iwl_pcie_int_cause_ict(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 inta;
        u32 val = 0;
        u32 read;

        trace_iwlwifi_dev_irq(trans->dev);

        /* Ignore interrupt if there's nothing in NIC to service.
         * This may be due to IRQ shared with another device,
         * or due to sporadic interrupts thrown from our NIC. */
        read = le32_to_cpu(trans_pcie->ict_tbl[trans_pcie->ict_index]);
        trace_iwlwifi_dev_ict_read(trans->dev, trans_pcie->ict_index, read);
        if (!read)
                return 0;

        /*
         * Collect all entries up to the first 0, starting from ict_index;
         * note we already read at ict_index.
         */
        do {
                val |= read;
                IWL_DEBUG_ISR(trans, "ICT index %d value 0x%08X\n",
                                trans_pcie->ict_index, read);
                trans_pcie->ict_tbl[trans_pcie->ict_index] = 0;
                trans_pcie->ict_index =
                        ((trans_pcie->ict_index + 1) & (ICT_COUNT - 1));

                read = le32_to_cpu(trans_pcie->ict_tbl[trans_pcie->ict_index]);
                trace_iwlwifi_dev_ict_read(trans->dev, trans_pcie->ict_index,
                                           read);
        } while (read);

        /* We should not get this value, just ignore it. */
        if (val == 0xffffffff)
                val = 0;

        /*
         * this is a w/a for a h/w bug. the h/w bug may cause the Rx bit
         * (bit 15 before shifting it to 31) to clear when using interrupt
         * coalescing. fortunately, bits 18 and 19 stay set when this happens
         * so we use them to decide on the real state of the Rx bit.
         * In order words, bit 15 is set if bit 18 or bit 19 are set.
         */
        if (val & 0xC0000)
                val |= 0x8000;

        inta = (0xff & val) | ((0xff00 & val) << 16);
        return inta;
}

void iwl_pcie_handle_rfkill_irq(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct isr_statistics *isr_stats = &trans_pcie->isr_stats;
        bool hw_rfkill, prev, report;

        mutex_lock(&trans_pcie->mutex);
        prev = test_bit(STATUS_RFKILL_OPMODE, &trans->status);
        hw_rfkill = iwl_is_rfkill_set(trans);
        if (hw_rfkill) {
                set_bit(STATUS_RFKILL_OPMODE, &trans->status);
                set_bit(STATUS_RFKILL_HW, &trans->status);
        }
        if (trans_pcie->opmode_down)
                report = hw_rfkill;
        else
                report = test_bit(STATUS_RFKILL_OPMODE, &trans->status);

        IWL_WARN(trans, "RF_KILL bit toggled to %s.\n",
                 hw_rfkill ? "disable radio" : "enable radio");

        isr_stats->rfkill++;

        if (prev != report)
                iwl_trans_pcie_rf_kill(trans, report);
        mutex_unlock(&trans_pcie->mutex);

        if (hw_rfkill) {
                if (test_and_clear_bit(STATUS_SYNC_HCMD_ACTIVE,
                                       &trans->status))
                        IWL_DEBUG_RF_KILL(trans,
                                          "Rfkill while SYNC HCMD in flight\n");
                wake_up(&trans_pcie->wait_command_queue);
        } else {
                clear_bit(STATUS_RFKILL_HW, &trans->status);
                if (trans_pcie->opmode_down)
                        clear_bit(STATUS_RFKILL_OPMODE, &trans->status);
        }
}

irqreturn_t iwl_pcie_irq_handler(int irq, void *dev_id)
{
        struct iwl_trans *trans = dev_id;
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        struct isr_statistics *isr_stats = &trans_pcie->isr_stats;
        u32 inta = 0;
        u32 handled = 0;
        bool polling = false;

        lock_map_acquire(&trans->sync_cmd_lockdep_map);

        spin_lock_bh(&trans_pcie->irq_lock);

        /* dram interrupt table not set yet,
         * use legacy interrupt.
         */
        if (likely(trans_pcie->use_ict))
                inta = iwl_pcie_int_cause_ict(trans);
        else
                inta = iwl_pcie_int_cause_non_ict(trans);

        if (iwl_have_debug_level(IWL_DL_ISR)) {
                IWL_DEBUG_ISR(trans,
                              "ISR inta 0x%08x, enabled 0x%08x(sw), enabled(hw) 0x%08x, fh 0x%08x\n",
                              inta, trans_pcie->inta_mask,
                              iwl_read32(trans, CSR_INT_MASK),
                              iwl_read32(trans, CSR_FH_INT_STATUS));
                if (inta & (~trans_pcie->inta_mask))
                        IWL_DEBUG_ISR(trans,
                                      "We got a masked interrupt (0x%08x)\n",
                                      inta & (~trans_pcie->inta_mask));
        }

        inta &= trans_pcie->inta_mask;

        /*
         * Ignore interrupt if there's nothing in NIC to service.
         * This may be due to IRQ shared with another device,
         * or due to sporadic interrupts thrown from our NIC.
         */
        if (unlikely(!inta)) {
                IWL_DEBUG_ISR(trans, "Ignore interrupt, inta == 0\n");
                /*
                 * Re-enable interrupts here since we don't
                 * have anything to service
                 */
                if (test_bit(STATUS_INT_ENABLED, &trans->status))
                        _iwl_enable_interrupts(trans);
                spin_unlock_bh(&trans_pcie->irq_lock);
                lock_map_release(&trans->sync_cmd_lockdep_map);
                return IRQ_NONE;
        }

        if (unlikely(inta == 0xFFFFFFFF || (inta & 0xFFFFFFF0) == 0xa5a5a5a0)) {
                /*
                 * Hardware disappeared. It might have
                 * already raised an interrupt.
                 */
                IWL_WARN(trans, "HARDWARE GONE?? INTA == 0x%08x\n", inta);
                spin_unlock_bh(&trans_pcie->irq_lock);
                goto out;
        }

        /* Ack/clear/reset pending uCode interrupts.
         * Note:  Some bits in CSR_INT are "OR" of bits in CSR_FH_INT_STATUS,
         */
        /* There is a hardware bug in the interrupt mask function that some
         * interrupts (i.e. CSR_INT_BIT_SCD) can still be generated even if
         * they are disabled in the CSR_INT_MASK register. Furthermore the
         * ICT interrupt handling mechanism has another bug that might cause
         * these unmasked interrupts fail to be detected. We workaround the
         * hardware bugs here by ACKing all the possible interrupts so that
         * interrupt coalescing can still be achieved.
         */
        iwl_write32(trans, CSR_INT, inta | ~trans_pcie->inta_mask);

        if (iwl_have_debug_level(IWL_DL_ISR))
                IWL_DEBUG_ISR(trans, "inta 0x%08x, enabled 0x%08x\n",
                              inta, iwl_read32(trans, CSR_INT_MASK));

        spin_unlock_bh(&trans_pcie->irq_lock);

        /* Now service all interrupt bits discovered above. */
        if (inta & CSR_INT_BIT_HW_ERR) {
                IWL_ERR(trans, "Hardware error detected.  Restarting.\n");

                /* Tell the device to stop sending interrupts */
                iwl_disable_interrupts(trans);

                isr_stats->hw++;
                iwl_pcie_irq_handle_error(trans);

                handled |= CSR_INT_BIT_HW_ERR;

                goto out;
        }

        /* NIC fires this, but we don't use it, redundant with WAKEUP */
        if (inta & CSR_INT_BIT_SCD) {
                IWL_DEBUG_ISR(trans,
                              "Scheduler finished to transmit the frame/frames.\n");
                isr_stats->sch++;
        }

        /* Alive notification via Rx interrupt will do the real work */
        if (inta & CSR_INT_BIT_ALIVE) {
                IWL_DEBUG_ISR(trans, "Alive interrupt\n");
                isr_stats->alive++;
                if (trans->trans_cfg->gen2) {
                        /*
                         * We can restock, since firmware configured
                         * the RFH
                         */
                        iwl_pcie_rxmq_restock(trans, trans_pcie->rxq);
                }

                handled |= CSR_INT_BIT_ALIVE;
        }

        /* Safely ignore these bits for debug checks below */
        inta &= ~(CSR_INT_BIT_SCD | CSR_INT_BIT_ALIVE);

        /* HW RF KILL switch toggled */
        if (inta & CSR_INT_BIT_RF_KILL) {
                iwl_pcie_handle_rfkill_irq(trans);
                handled |= CSR_INT_BIT_RF_KILL;
        }

        /* Chip got too hot and stopped itself */
        if (inta & CSR_INT_BIT_CT_KILL) {
                IWL_ERR(trans, "Microcode CT kill error detected.\n");
                isr_stats->ctkill++;
                handled |= CSR_INT_BIT_CT_KILL;
        }

        /* Error detected by uCode */
        if (inta & CSR_INT_BIT_SW_ERR) {
                IWL_ERR(trans, "Microcode SW error detected. "
                        " Restarting 0x%X.\n", inta);
                isr_stats->sw++;
                iwl_pcie_irq_handle_error(trans);
                handled |= CSR_INT_BIT_SW_ERR;
        }

        /* uCode wakes up after power-down sleep */
        if (inta & CSR_INT_BIT_WAKEUP) {
                IWL_DEBUG_ISR(trans, "Wakeup interrupt\n");
                iwl_pcie_rxq_check_wrptr(trans);
                iwl_pcie_txq_check_wrptrs(trans);

                isr_stats->wakeup++;

                handled |= CSR_INT_BIT_WAKEUP;
        }

        /* All uCode command responses, including Tx command responses,
         * Rx "responses" (frame-received notification), and other
         * notifications from uCode come through here*/
        if (inta & (CSR_INT_BIT_FH_RX | CSR_INT_BIT_SW_RX |
                    CSR_INT_BIT_RX_PERIODIC)) {
                IWL_DEBUG_ISR(trans, "Rx interrupt\n");
                if (inta & (CSR_INT_BIT_FH_RX | CSR_INT_BIT_SW_RX)) {
                        handled |= (CSR_INT_BIT_FH_RX | CSR_INT_BIT_SW_RX);
                        iwl_write32(trans, CSR_FH_INT_STATUS,
                                        CSR_FH_INT_RX_MASK);
                }
                if (inta & CSR_INT_BIT_RX_PERIODIC) {
                        handled |= CSR_INT_BIT_RX_PERIODIC;
                        iwl_write32(trans,
                                CSR_INT, CSR_INT_BIT_RX_PERIODIC);
                }
                /* Sending RX interrupt require many steps to be done in the
                 * the device:
                 * 1- write interrupt to current index in ICT table.
                 * 2- dma RX frame.
                 * 3- update RX shared data to indicate last write index.
                 * 4- send interrupt.
                 * This could lead to RX race, driver could receive RX interrupt
                 * but the shared data changes does not reflect this;
                 * periodic interrupt will detect any dangling Rx activity.
                 */

                /* Disable periodic interrupt; we use it as just a one-shot. */
                iwl_write8(trans, CSR_INT_PERIODIC_REG,
                            CSR_INT_PERIODIC_DIS);

                /*
                 * Enable periodic interrupt in 8 msec only if we received
                 * real RX interrupt (instead of just periodic int), to catch
                 * any dangling Rx interrupt.  If it was just the periodic
                 * interrupt, there was no dangling Rx activity, and no need
                 * to extend the periodic interrupt; one-shot is enough.
                 */
                if (inta & (CSR_INT_BIT_FH_RX | CSR_INT_BIT_SW_RX))
                        iwl_write8(trans, CSR_INT_PERIODIC_REG,
                                   CSR_INT_PERIODIC_ENA);

                isr_stats->rx++;

                local_bh_disable();
                if (napi_schedule_prep(&trans_pcie->rxq[0].napi)) {
                        polling = true;
                        __napi_schedule(&trans_pcie->rxq[0].napi);
                }
                local_bh_enable();
        }

        /* This "Tx" DMA channel is used only for loading uCode */
        if (inta & CSR_INT_BIT_FH_TX) {
                iwl_write32(trans, CSR_FH_INT_STATUS, CSR_FH_INT_TX_MASK);
                IWL_DEBUG_ISR(trans, "uCode load interrupt\n");
                isr_stats->tx++;
                handled |= CSR_INT_BIT_FH_TX;
                /* Wake up uCode load routine, now that load is complete */
                trans_pcie->ucode_write_complete = true;
                wake_up(&trans_pcie->ucode_write_waitq);
        }

        if (inta & ~handled) {
                IWL_ERR(trans, "Unhandled INTA bits 0x%08x\n", inta & ~handled);
                isr_stats->unhandled++;
        }

        if (inta & ~(trans_pcie->inta_mask)) {
                IWL_WARN(trans, "Disabled INTA bits 0x%08x were pending\n",
                         inta & ~trans_pcie->inta_mask);
        }

        if (!polling) {
                spin_lock_bh(&trans_pcie->irq_lock);
                /* only Re-enable all interrupt if disabled by irq */
                if (test_bit(STATUS_INT_ENABLED, &trans->status))
                        _iwl_enable_interrupts(trans);
                /* we are loading the firmware, enable FH_TX interrupt only */
                else if (handled & CSR_INT_BIT_FH_TX)
                        iwl_enable_fw_load_int(trans);
                /* Re-enable RF_KILL if it occurred */
                else if (handled & CSR_INT_BIT_RF_KILL)
                        iwl_enable_rfkill_int(trans);
                /* Re-enable the ALIVE / Rx interrupt if it occurred */
                else if (handled & (CSR_INT_BIT_ALIVE | CSR_INT_BIT_FH_RX))
                        iwl_enable_fw_load_int_ctx_info(trans);
                spin_unlock_bh(&trans_pcie->irq_lock);
        }

out:
        lock_map_release(&trans->sync_cmd_lockdep_map);
        return IRQ_HANDLED;
}

/******************************************************************************
 *
 * ICT functions
 *
 ******************************************************************************/

/* Free dram table */
void iwl_pcie_free_ict(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

        if (trans_pcie->ict_tbl) {
                dma_free_coherent(trans->dev, ICT_SIZE,
                                  trans_pcie->ict_tbl,
                                  trans_pcie->ict_tbl_dma);
                trans_pcie->ict_tbl = NULL;
                trans_pcie->ict_tbl_dma = 0;
        }
}

/*
 * allocate dram shared table, it is an aligned memory
 * block of ICT_SIZE.
 * also reset all data related to ICT table interrupt.
 */
int iwl_pcie_alloc_ict(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

        trans_pcie->ict_tbl =
                dma_alloc_coherent(trans->dev, ICT_SIZE,
                                   &trans_pcie->ict_tbl_dma, GFP_KERNEL);
        if (!trans_pcie->ict_tbl)
                return -ENOMEM;

        /* just an API sanity check ... it is guaranteed to be aligned */
        if (WARN_ON(trans_pcie->ict_tbl_dma & (ICT_SIZE - 1))) {
                iwl_pcie_free_ict(trans);
                return -EINVAL;
        }

        return 0;
}

/* Device is going up inform it about using ICT interrupt table,
 * also we need to tell the driver to start using ICT interrupt.
 */
void iwl_pcie_reset_ict(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 val;

        if (!trans_pcie->ict_tbl)
                return;

        spin_lock_bh(&trans_pcie->irq_lock);
        _iwl_disable_interrupts(trans);

        memset(trans_pcie->ict_tbl, 0, ICT_SIZE);

        val = trans_pcie->ict_tbl_dma >> ICT_SHIFT;

        val |= CSR_DRAM_INT_TBL_ENABLE |
               CSR_DRAM_INIT_TBL_WRAP_CHECK |
               CSR_DRAM_INIT_TBL_WRITE_POINTER;

        IWL_DEBUG_ISR(trans, "CSR_DRAM_INT_TBL_REG =0x%x\n", val);

        iwl_write32(trans, CSR_DRAM_INT_TBL_REG, val);
        trans_pcie->use_ict = true;
        trans_pcie->ict_index = 0;
        iwl_write32(trans, CSR_INT, trans_pcie->inta_mask);
        _iwl_enable_interrupts(trans);
        spin_unlock_bh(&trans_pcie->irq_lock);
}

/* Device is going down disable ict interrupt usage */
void iwl_pcie_disable_ict(struct iwl_trans *trans)
{
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

        spin_lock_bh(&trans_pcie->irq_lock);
        trans_pcie->use_ict = false;
        spin_unlock_bh(&trans_pcie->irq_lock);
}

irqreturn_t iwl_pcie_isr(int irq, void *data)
{
        struct iwl_trans *trans = data;

        if (!trans)
                return IRQ_NONE;

        /* Disable (but don't clear!) interrupts here to avoid
         * back-to-back ISRs and sporadic interrupts from our NIC.
         * If we have something to service, the tasklet will re-enable ints.
         * If we *don't* have something, we'll re-enable before leaving here.
         */
        iwl_write32(trans, CSR_INT_MASK, 0x00000000);

        return IRQ_WAKE_THREAD;
}

irqreturn_t iwl_pcie_msix_isr(int irq, void *data)
{
        return IRQ_WAKE_THREAD;
}

irqreturn_t iwl_pcie_irq_msix_handler(int irq, void *dev_id)
{
        struct msix_entry *entry = dev_id;
        struct iwl_trans_pcie *trans_pcie = iwl_pcie_get_trans_pcie(entry);
        struct iwl_trans *trans = trans_pcie->trans;
        struct isr_statistics *isr_stats = &trans_pcie->isr_stats;
        u32 inta_fh, inta_hw;
        bool polling = false;

        lock_map_acquire(&trans->sync_cmd_lockdep_map);

        spin_lock_bh(&trans_pcie->irq_lock);
        inta_fh = iwl_read32(trans, CSR_MSIX_FH_INT_CAUSES_AD);
        inta_hw = iwl_read32(trans, CSR_MSIX_HW_INT_CAUSES_AD);
        /*
         * Clear causes registers to avoid being handling the same cause.
         */
        iwl_write32(trans, CSR_MSIX_FH_INT_CAUSES_AD, inta_fh);
        iwl_write32(trans, CSR_MSIX_HW_INT_CAUSES_AD, inta_hw);
        spin_unlock_bh(&trans_pcie->irq_lock);

        trace_iwlwifi_dev_irq_msix(trans->dev, entry, true, inta_fh, inta_hw);

        if (unlikely(!(inta_fh | inta_hw))) {
                IWL_DEBUG_ISR(trans, "Ignore interrupt, inta == 0\n");
                lock_map_release(&trans->sync_cmd_lockdep_map);
                return IRQ_NONE;
        }

        if (iwl_have_debug_level(IWL_DL_ISR)) {
                IWL_DEBUG_ISR(trans,
                              "ISR inta_fh 0x%08x, enabled (sw) 0x%08x (hw) 0x%08x\n",
                              inta_fh, trans_pcie->fh_mask,
                              iwl_read32(trans, CSR_MSIX_FH_INT_MASK_AD));
                if (inta_fh & ~trans_pcie->fh_mask)
                        IWL_DEBUG_ISR(trans,
                                      "We got a masked interrupt (0x%08x)\n",
                                      inta_fh & ~trans_pcie->fh_mask);
        }

        inta_fh &= trans_pcie->fh_mask;

        if ((trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_NON_RX) &&
            inta_fh & MSIX_FH_INT_CAUSES_Q0) {
                local_bh_disable();
                if (napi_schedule_prep(&trans_pcie->rxq[0].napi)) {
                        polling = true;
                        __napi_schedule(&trans_pcie->rxq[0].napi);
                }
                local_bh_enable();
        }

        if ((trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_FIRST_RSS) &&
            inta_fh & MSIX_FH_INT_CAUSES_Q1) {
                local_bh_disable();
                if (napi_schedule_prep(&trans_pcie->rxq[1].napi)) {
                        polling = true;
                        __napi_schedule(&trans_pcie->rxq[1].napi);
                }
                local_bh_enable();
        }

        /* This "Tx" DMA channel is used only for loading uCode */
        if (inta_fh & MSIX_FH_INT_CAUSES_D2S_CH0_NUM) {
                IWL_DEBUG_ISR(trans, "uCode load interrupt\n");
                isr_stats->tx++;
                /*
                 * Wake up uCode load routine,
                 * now that load is complete
                 */
                trans_pcie->ucode_write_complete = true;
                wake_up(&trans_pcie->ucode_write_waitq);
        }

        /* Error detected by uCode */
        if ((inta_fh & MSIX_FH_INT_CAUSES_FH_ERR) ||
            (inta_hw & MSIX_HW_INT_CAUSES_REG_SW_ERR)) {
                IWL_ERR(trans,
                        "Microcode SW error detected. Restarting 0x%X.\n",
                        inta_fh);
                isr_stats->sw++;
                iwl_pcie_irq_handle_error(trans);
        }

        /* After checking FH register check HW register */
        if (iwl_have_debug_level(IWL_DL_ISR)) {
                IWL_DEBUG_ISR(trans,
                              "ISR inta_hw 0x%08x, enabled (sw) 0x%08x (hw) 0x%08x\n",
                              inta_hw, trans_pcie->hw_mask,
                              iwl_read32(trans, CSR_MSIX_HW_INT_MASK_AD));
                if (inta_hw & ~trans_pcie->hw_mask)
                        IWL_DEBUG_ISR(trans,
                                      "We got a masked interrupt 0x%08x\n",
                                      inta_hw & ~trans_pcie->hw_mask);
        }

        inta_hw &= trans_pcie->hw_mask;

        /* Alive notification via Rx interrupt will do the real work */
        if (inta_hw & MSIX_HW_INT_CAUSES_REG_ALIVE) {
                IWL_DEBUG_ISR(trans, "Alive interrupt\n");
                isr_stats->alive++;
                if (trans->trans_cfg->gen2) {
                        /* We can restock, since firmware configured the RFH */
                        iwl_pcie_rxmq_restock(trans, trans_pcie->rxq);
                }
        }

        if (inta_hw & MSIX_HW_INT_CAUSES_REG_WAKEUP) {
                u32 sleep_notif =
                        le32_to_cpu(trans_pcie->prph_info->sleep_notif);
                if (sleep_notif == IWL_D3_SLEEP_STATUS_SUSPEND ||
                    sleep_notif == IWL_D3_SLEEP_STATUS_RESUME) {
                        IWL_DEBUG_ISR(trans,
                                      "Sx interrupt: sleep notification = 0x%x\n",
                                      sleep_notif);
                        trans_pcie->sx_complete = true;
                        wake_up(&trans_pcie->sx_waitq);
                } else {
                        /* uCode wakes up after power-down sleep */
                        IWL_DEBUG_ISR(trans, "Wakeup interrupt\n");
                        iwl_pcie_rxq_check_wrptr(trans);
                        iwl_pcie_txq_check_wrptrs(trans);

                        isr_stats->wakeup++;
                }
        }

        /* Chip got too hot and stopped itself */
        if (inta_hw & MSIX_HW_INT_CAUSES_REG_CT_KILL) {
                IWL_ERR(trans, "Microcode CT kill error detected.\n");
                isr_stats->ctkill++;
        }

        /* HW RF KILL switch toggled */
        if (inta_hw & MSIX_HW_INT_CAUSES_REG_RF_KILL)
                iwl_pcie_handle_rfkill_irq(trans);

        if (inta_hw & MSIX_HW_INT_CAUSES_REG_HW_ERR) {
                IWL_ERR(trans,
                        "Hardware error detected. Restarting.\n");

                isr_stats->hw++;
                trans->dbg.hw_error = true;
                iwl_pcie_irq_handle_error(trans);
        }

        if (inta_hw & MSIX_HW_INT_CAUSES_REG_RESET_DONE) {
                IWL_DEBUG_ISR(trans, "Reset flow completed\n");
                trans_pcie->fw_reset_done = true;
                wake_up(&trans_pcie->fw_reset_waitq);
        }

        if (!polling)
                iwl_pcie_clear_irq(trans, entry->entry);

        lock_map_release(&trans->sync_cmd_lockdep_map);

        return IRQ_HANDLED;
}