Exemplo n.º 1
0
Arquivo: rx.c Projeto: sosilent/kis_pc
static void iwl_rx_handle_rxbuf(struct iwl_trans *trans,
                                struct iwl_rx_mem_buffer *rxb)
{
    struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
    struct iwl_rx_queue *rxq = &trans_pcie->rxq;
    struct iwl_tx_queue *txq = &trans_pcie->txq[trans_pcie->cmd_queue];
    unsigned long flags;
    bool page_stolen = false;
    int max_len = PAGE_SIZE << trans_pcie->rx_page_order;
    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;
        struct iwl_device_cmd *cmd;
        u16 sequence;
        bool reclaim;
        int index, cmd_index, err, len;
        struct iwl_rx_cmd_buffer rxcb = {
            ._offset = offset,
            ._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))
            break;

        IWL_DEBUG_RX(trans, "cmd at offset %d: %s (0x%.2x)\n",
                     rxcb._offset,
                     trans_pcie_get_cmd_string(trans_pcie, pkt->hdr.cmd),
                     pkt->hdr.cmd);

        len = le32_to_cpu(pkt->len_n_flags) & FH_RSCSR_FRAME_SIZE_MSK;
        len += sizeof(u32); /* account for status word */
        trace_iwlwifi_dev_rx(trans->dev, 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) {
            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;
                }
            }
        }

        sequence = le16_to_cpu(pkt->hdr.sequence);
        index = SEQ_TO_INDEX(sequence);
        cmd_index = get_cmd_index(&txq->q, index);

        if (reclaim) {
            struct iwl_pcie_tx_queue_entry *ent;
            ent = &txq->entries[cmd_index];
            cmd = ent->copy_cmd;
            WARN_ON_ONCE(!cmd && ent->meta.flags & CMD_WANT_HCMD);
        } else {
            cmd = NULL;
        }

        err = iwl_op_mode_rx(trans->op_mode, &rxcb, cmd);

        if (reclaim) {
            /* The original command isn't needed any more */
            kfree(txq->entries[cmd_index].copy_cmd);
            txq->entries[cmd_index].copy_cmd = NULL;
        }

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

        if (reclaim) {
            /* 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_tx_cmd_complete(trans, &rxcb, err);
            else
                IWL_WARN(trans, "Claim null rxb?\n");
        }

        page_stolen |= rxcb._page_stolen;
        offset += ALIGN(len, FH_RSCSR_FRAME_ALIGN);
    }

    /* 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. */
    spin_lock_irqsave(&rxq->lock, flags);
    if (rxb->page != NULL) {
        rxb->page_dma =
            dma_map_page(trans->dev, rxb->page, 0,
                         PAGE_SIZE << trans_pcie->rx_page_order,
                         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;
            list_add_tail(&rxb->list, &rxq->rx_used);
        } else {
            list_add_tail(&rxb->list, &rxq->rx_free);
            rxq->free_count++;
        }
    } else
        list_add_tail(&rxb->list, &rxq->rx_used);
    spin_unlock_irqrestore(&rxq->lock, flags);
}

/**
 * iwl_rx_handle - Main entry function for receiving responses from uCode
 *
 * Uses the priv->rx_handlers callback function array to invoke
 * the appropriate handlers, including command responses,
 * frame-received notifications, and other notifications.
 */
static void iwl_rx_handle(struct iwl_trans *trans)
{
    struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
    struct iwl_rx_queue *rxq = &trans_pcie->rxq;
    u32 r, i;
    u8 fill_rx = 0;
    u32 count = 8;
    int total_empty;

    /* 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(rxq->rb_stts->closed_rb_num) &  0x0FFF;
    i = rxq->read;

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

    /* calculate total frames need to be restock after handling RX */
    total_empty = r - rxq->write_actual;
    if (total_empty < 0)
        total_empty += RX_QUEUE_SIZE;

    if (total_empty > (RX_QUEUE_SIZE / 2))
        fill_rx = 1;

    while (i != r) {
        struct iwl_rx_mem_buffer *rxb;

        rxb = rxq->queue[i];
        rxq->queue[i] = NULL;

        IWL_DEBUG_RX(trans, "rxbuf: HW = %d, SW = %d (%p)\n",
                     r, i, rxb);
        iwl_rx_handle_rxbuf(trans, rxb);

        i = (i + 1) & RX_QUEUE_MASK;
        /* If there are a lot of unused frames,
         * restock the Rx queue so ucode wont assert. */
        if (fill_rx) {
            count++;
            if (count >= 8) {
                rxq->read = i;
                iwl_rx_replenish_now(trans);
                count = 0;
            }
        }
    }

    /* Backtrack one entry */
    rxq->read = i;
    if (fill_rx)
        iwl_rx_replenish_now(trans);
    else
        iwl_rx_queue_restock(trans);
}

/**
 * iwl_irq_handle_error - called for HW or SW error interrupt from card
 */
static void iwl_irq_handle_error(struct iwl_trans *trans)
{
    /* W/A for WiFi/WiMAX coex and WiMAX own the RF */
    if (trans->cfg->internal_wimax_coex &&
            (!(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))) {
        struct iwl_trans_pcie *trans_pcie =
            IWL_TRANS_GET_PCIE_TRANS(trans);

        clear_bit(STATUS_HCMD_ACTIVE, &trans_pcie->status);
        iwl_op_mode_wimax_active(trans->op_mode);
        wake_up(&trans->wait_command_queue);
        return;
    }

    iwl_dump_csr(trans);
    iwl_dump_fh(trans, NULL);

    iwl_op_mode_nic_error(trans->op_mode);
}

/* tasklet for iwlagn interrupt */
void iwl_irq_tasklet(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;
    u32 inta = 0;
    u32 handled = 0;
    unsigned long flags;
    u32 i;
#ifdef CONFIG_IWLWIFI_DEBUG
    u32 inta_mask;
#endif

    spin_lock_irqsave(&trans_pcie->irq_lock, flags);

    /* 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,
                trans_pcie->inta | ~trans_pcie->inta_mask);

    inta = trans_pcie->inta;

#ifdef CONFIG_IWLWIFI_DEBUG
    if (iwl_have_debug_level(IWL_DL_ISR)) {
        /* just for debug */
        inta_mask = iwl_read32(trans, CSR_INT_MASK);
        IWL_DEBUG_ISR(trans, "inta 0x%08x, enabled 0x%08x\n",
                      inta, inta_mask);
    }
#endif

    /* saved interrupt in inta variable now we can reset trans_pcie->inta */
    trans_pcie->inta = 0;

    spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);

    /* 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_irq_handle_error(trans);

        handled |= CSR_INT_BIT_HW_ERR;

        return;
    }

#ifdef CONFIG_IWLWIFI_DEBUG
    if (iwl_have_debug_level(IWL_DL_ISR)) {
        /* 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++;
        }
    }
#endif
    /* 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) {
        bool hw_rfkill;

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

        isr_stats->rfkill++;

        iwl_op_mode_hw_rf_kill(trans->op_mode, hw_rfkill);

        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_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_rx_queue_update_write_ptr(trans, &trans_pcie->rxq);
        for (i = 0; i < trans->cfg->base_params->num_of_queues; i++)
            iwl_txq_update_write_ptr(trans,
                                     &trans_pcie->txq[i]);

        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);

        iwl_rx_handle(trans);

        /*
         * 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++;
    }

    /* 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);
    }

    /* Re-enable all interrupts */
    /* only Re-enable if disabled by irq */
    if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status))
        iwl_enable_interrupts(trans);
    /* Re-enable RF_KILL if it occurred */
    else if (handled & CSR_INT_BIT_RF_KILL)
        iwl_enable_rfkill_int(trans);
}

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

/* 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))

/* Free dram table */
void iwl_free_isr_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_alloc_isr_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_free_isr_ict(trans);
        return -EINVAL;
    }

    IWL_DEBUG_ISR(trans, "ict dma addr %Lx\n",
                  (unsigned long long)trans_pcie->ict_tbl_dma);

    IWL_DEBUG_ISR(trans, "ict vir addr %p\n", trans_pcie->ict_tbl);

    /* reset table and index to all 0 */
    memset(trans_pcie->ict_tbl, 0, ICT_SIZE);
    trans_pcie->ict_index = 0;

    /* add periodic RX interrupt */
    trans_pcie->inta_mask |= CSR_INT_BIT_RX_PERIODIC;
    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_reset_ict(struct iwl_trans *trans)
{
    struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
    u32 val;
    unsigned long flags;

    if (!trans_pcie->ict_tbl)
        return;

    spin_lock_irqsave(&trans_pcie->irq_lock, flags);
    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;
    val |= CSR_DRAM_INIT_TBL_WRAP_CHECK;

    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_irqrestore(&trans_pcie->irq_lock, flags);
}

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

    spin_lock_irqsave(&trans_pcie->irq_lock, flags);
    trans_pcie->use_ict = false;
    spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
}

/* legacy (non-ICT) ISR. Assumes that trans_pcie->irq_lock is held */
static irqreturn_t iwl_isr(int irq, void *data)
{
    struct iwl_trans *trans = data;
    struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
    u32 inta, inta_mask;
#ifdef CONFIG_IWLWIFI_DEBUG
    u32 inta_fh;
#endif

    lockdep_assert_held(&trans_pcie->irq_lock);

    trace_iwlwifi_dev_irq(trans->dev);

    /* 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. */
    inta_mask = iwl_read32(trans, CSR_INT_MASK);
    iwl_write32(trans, CSR_INT_MASK, 0x00000000);

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

    if (inta & (~inta_mask)) {
        IWL_DEBUG_ISR(trans,
                      "We got a masked interrupt (0x%08x)...Ack and ignore\n",
                      inta & (~inta_mask));
        iwl_write32(trans, CSR_INT, inta & (~inta_mask));
        inta &= 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 (!inta) {
        IWL_DEBUG_ISR(trans, "Ignore interrupt, inta == 0\n");
        goto none;
    }

    if ((inta == 0xFFFFFFFF) || ((inta & 0xFFFFFFF0) == 0xa5a5a5a0)) {
        /* Hardware disappeared. It might have already raised
         * an interrupt */
        IWL_WARN(trans, "HARDWARE GONE?? INTA == 0x%08x\n", inta);
        return IRQ_HANDLED;
    }

#ifdef CONFIG_IWLWIFI_DEBUG
    if (iwl_have_debug_level(IWL_DL_ISR)) {
        inta_fh = iwl_read32(trans, CSR_FH_INT_STATUS);
        IWL_DEBUG_ISR(trans, "ISR inta 0x%08x, enabled 0x%08x, "
                      "fh 0x%08x\n", inta, inta_mask, inta_fh);
    }
#endif

    trans_pcie->inta |= inta;
    /* iwl_irq_tasklet() will service interrupts and re-enable them */
    if (likely(inta))
        tasklet_schedule(&trans_pcie->irq_tasklet);
    else if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
             !trans_pcie->inta)
        iwl_enable_interrupts(trans);
    return IRQ_HANDLED;

none:
    /* re-enable interrupts here since we don't have anything to service. */
    /* only Re-enable if disabled by irq  and no schedules tasklet. */
    if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
            !trans_pcie->inta)
        iwl_enable_interrupts(trans);

    return IRQ_NONE;
}

/* 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.
 */
irqreturn_t iwl_isr_ict(int irq, void *data)
{
    struct iwl_trans *trans = data;
    struct iwl_trans_pcie *trans_pcie;
    u32 inta, inta_mask;
    u32 val = 0;
    u32 read;
    unsigned long flags;

    if (!trans)
        return IRQ_NONE;

    trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

    spin_lock_irqsave(&trans_pcie->irq_lock, flags);

    /* dram interrupt table not set yet,
     * use legacy interrupt.
     */
    if (unlikely(!trans_pcie->use_ict)) {
        irqreturn_t ret = iwl_isr(irq, data);
        spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
        return ret;
    }

    trace_iwlwifi_dev_irq(trans->dev);


    /* 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.
     */
    inta_mask = iwl_read32(trans, CSR_INT_MASK);
    iwl_write32(trans, CSR_INT_MASK, 0x00000000);


    /* 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) {
        IWL_DEBUG_ISR(trans, "Ignore interrupt, inta == 0\n");
        goto none;
    }

    /*
     * 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 =
            iwl_queue_inc_wrap(trans_pcie->ict_index, ICT_COUNT);

        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);
    IWL_DEBUG_ISR(trans, "ISR inta 0x%08x, enabled 0x%08x ict 0x%08x\n",
                  inta, inta_mask, val);

    inta &= trans_pcie->inta_mask;
    trans_pcie->inta |= inta;

    /* iwl_irq_tasklet() will service interrupts and re-enable them */
    if (likely(inta))
        tasklet_schedule(&trans_pcie->irq_tasklet);
    else if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
             !trans_pcie->inta) {
        /* Allow interrupt if was disabled by this handler and
         * no tasklet was schedules, We should not enable interrupt,
         * tasklet will enable it.
         */
        iwl_enable_interrupts(trans);
    }

    spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
    return IRQ_HANDLED;

none:
    /* re-enable interrupts here since we don't have anything to service.
     * only Re-enable if disabled by irq.
     */
    if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
            !trans_pcie->inta)
        iwl_enable_interrupts(trans);

    spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
    return IRQ_NONE;
}
/* tasklet for iwlagn interrupt */
void iwl_irq_tasklet(struct iwl_trans *trans)
{
	u32 inta = 0;
	u32 handled = 0;
	unsigned long flags;
	u32 i;
#ifdef CONFIG_IWLWIFI_DEBUG
	u32 inta_mask;
#endif

	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
	struct isr_statistics *isr_stats = &trans_pcie->isr_stats;


	spin_lock_irqsave(&trans->shrd->lock, flags);

	/* 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(bus(trans), CSR_INT,
		trans_pcie->inta | ~trans_pcie->inta_mask);

	inta = trans_pcie->inta;

#ifdef CONFIG_IWLWIFI_DEBUG
	if (iwl_get_debug_level(trans->shrd) & IWL_DL_ISR) {
		/* just for debug */
		inta_mask = iwl_read32(bus(trans), CSR_INT_MASK);
		IWL_DEBUG_ISR(trans, "inta 0x%08x, enabled 0x%08x\n ",
				inta, inta_mask);
	}
#endif

	spin_unlock_irqrestore(&trans->shrd->lock, flags);

	/* saved interrupt in inta variable now we can reset trans_pcie->inta */
	trans_pcie->inta = 0;

	/* 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_irq_handle_error(trans);

		handled |= CSR_INT_BIT_HW_ERR;

		return;
	}

#ifdef CONFIG_IWLWIFI_DEBUG
	if (iwl_get_debug_level(trans->shrd) & (IWL_DL_ISR)) {
		/* 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++;
		}
	}
#endif
	/* 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) {
		int hw_rf_kill = 0;
		if (!(iwl_read32(bus(trans), CSR_GP_CNTRL) &
				CSR_GP_CNTRL_REG_FLAG_HW_RF_KILL_SW))
			hw_rf_kill = 1;

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

		isr_stats->rfkill++;

		/* driver only loads ucode once setting the interface up.
		 * the driver allows loading the ucode even if the radio
		 * is killed. Hence update the killswitch state here. The
		 * rfkill handler will care about restarting if needed.
		 */
		if (!test_bit(STATUS_ALIVE, &trans->shrd->status)) {
			if (hw_rf_kill)
				set_bit(STATUS_RF_KILL_HW,
					&trans->shrd->status);
			else
				clear_bit(STATUS_RF_KILL_HW,
					  &trans->shrd->status);
			iwl_set_hw_rfkill_state(priv(trans), hw_rf_kill);
		}

		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_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_rx_queue_update_write_ptr(trans, &trans_pcie->rxq);
		for (i = 0; i < hw_params(trans).max_txq_num; i++)
			iwl_txq_update_write_ptr(trans,
						 &trans_pcie->txq[i]);

		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(bus(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(bus(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(bus(trans), CSR_INT_PERIODIC_REG,
			    CSR_INT_PERIODIC_DIS);
		iwl_rx_handle(trans);

		/*
		 * 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(bus(trans), CSR_INT_PERIODIC_REG,
				    CSR_INT_PERIODIC_ENA);

		isr_stats->rx++;
	}

	/* This "Tx" DMA channel is used only for loading uCode */
	if (inta & CSR_INT_BIT_FH_TX) {
		iwl_write32(bus(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->ucode_write_complete = 1;
		wake_up(&trans->shrd->wait_command_queue);
	}

	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);
	}

	/* Re-enable all interrupts */
	/* only Re-enable if disabled by irq */
	if (test_bit(STATUS_INT_ENABLED, &trans->shrd->status))
		iwl_enable_interrupts(trans);
	/* Re-enable RF_KILL if it occurred */
	else if (handled & CSR_INT_BIT_RF_KILL)
		iwl_enable_rfkill_int(priv(trans));
}
void iwl_irq_tasklet(struct iwl_trans *trans)
{
	u32 inta = 0;
	u32 handled = 0;
	unsigned long flags;
	u32 i;
#ifdef CONFIG_IWLWIFI_DEBUG
	u32 inta_mask;
#endif

	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
	struct isr_statistics *isr_stats = &trans_pcie->isr_stats;


	spin_lock_irqsave(&trans_pcie->irq_lock, flags);

	/*                                          
                                                                      
  */
	/*                                                                 
                                                                    
                                                                   
                                                                     
                                                                    
                                                                    
                                               
  */
	iwl_write32(trans, CSR_INT,
		trans_pcie->inta | ~trans_pcie->inta_mask);

	inta = trans_pcie->inta;

#ifdef CONFIG_IWLWIFI_DEBUG
	if (iwl_have_debug_level(IWL_DL_ISR)) {
		/*                */
		inta_mask = iwl_read32(trans, CSR_INT_MASK);
		IWL_DEBUG_ISR(trans, "inta 0x%08x, enabled 0x%08x\n ",
				inta, inta_mask);
	}
#endif

	/*                                                                    */
	trans_pcie->inta = 0;

	spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);

	/*                                                  */
	if (inta & CSR_INT_BIT_HW_ERR) {
		IWL_ERR(trans, "Hardware error detected.  Restarting.\n");

		/*                                            */
		iwl_disable_interrupts(trans);

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

		handled |= CSR_INT_BIT_HW_ERR;

		return;
	}

#ifdef CONFIG_IWLWIFI_DEBUG
	if (iwl_have_debug_level(IWL_DL_ISR)) {
		/*                                                            */
		if (inta & CSR_INT_BIT_SCD) {
			IWL_DEBUG_ISR(trans, "Scheduler finished to transmit "
				      "the frame/frames.\n");
			isr_stats->sch++;
		}

		/*                                                           */
		if (inta & CSR_INT_BIT_ALIVE) {
			IWL_DEBUG_ISR(trans, "Alive interrupt\n");
			isr_stats->alive++;
		}
	}
#endif
	/*                                                 */
	inta &= ~(CSR_INT_BIT_SCD | CSR_INT_BIT_ALIVE);

	/*                           */
	if (inta & CSR_INT_BIT_RF_KILL) {
		bool hw_rfkill;

		hw_rfkill = !(iwl_read32(trans, CSR_GP_CNTRL) &
				CSR_GP_CNTRL_REG_FLAG_HW_RF_KILL_SW);
		IWL_WARN(trans, "RF_KILL bit toggled to %s.\n",
				hw_rfkill ? "disable radio" : "enable radio");

		isr_stats->rfkill++;

		iwl_op_mode_hw_rf_kill(trans->op_mode, hw_rfkill);

		handled |= CSR_INT_BIT_RF_KILL;
	}

	/*                                     */
	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;
	}

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

	/*                                       */
	if (inta & CSR_INT_BIT_WAKEUP) {
		IWL_DEBUG_ISR(trans, "Wakeup interrupt\n");
		iwl_rx_queue_update_write_ptr(trans, &trans_pcie->rxq);
		for (i = 0; i < cfg(trans)->base_params->num_of_queues; i++)
			iwl_txq_update_write_ptr(trans,
						 &trans_pcie->txq[i]);

		isr_stats->wakeup++;

		handled |= CSR_INT_BIT_WAKEUP;
	}

	/*                                                             
                                                           
                                              */
	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);
		}
		/*                                                          
                
                                                      
                     
                                                           
                       
                                                                  
                                                       
                                                             
   */

		/*                                                           */
		iwl_write8(trans, CSR_INT_PERIODIC_REG,
			    CSR_INT_PERIODIC_DIS);
#ifdef CONFIG_IWLWIFI_IDI
		iwl_amfh_rx_handler();
#else
		iwl_rx_handle(trans);
#endif
		/*
                                                            
                                                               
                                                            
                                                              
                                                          
   */
		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++;
	}

	/*                                                      */
	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;
		/*                                                       */
		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 (test_bit(STATUS_INT_ENABLED, &trans_pcie->status))
		iwl_enable_interrupts(trans);
	/*                                  */
	else if (handled & CSR_INT_BIT_RF_KILL)
		iwl_enable_rfkill_int(trans);
}