/*
 * This file is part of the Chelsio FCoE driver for Linux.
 *
 * Copyright (c) 2008-2012 Chelsio Communications, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/cpumask.h>
#include <linux/string.h>

#include "csio_init.h"
#include "csio_hw.h"

static irqreturn_t
csio_nondata_isr(int irq, void *dev_id)
{
        struct csio_hw *hw = (struct csio_hw *) dev_id;
        int rv;
        unsigned long flags;

        if (unlikely(!hw))
                return IRQ_NONE;

        if (unlikely(pci_channel_offline(hw->pdev))) {
                CSIO_INC_STATS(hw, n_pcich_offline);
                return IRQ_NONE;
        }

        spin_lock_irqsave(&hw->lock, flags);
        csio_hw_slow_intr_handler(hw);
        rv = csio_mb_isr_handler(hw);

        if (rv == 0 && !(hw->flags & CSIO_HWF_FWEVT_PENDING)) {
                hw->flags |= CSIO_HWF_FWEVT_PENDING;
                spin_unlock_irqrestore(&hw->lock, flags);
                schedule_work(&hw->evtq_work);
                return IRQ_HANDLED;
        }
        spin_unlock_irqrestore(&hw->lock, flags);
        return IRQ_HANDLED;
}

/*
 * csio_fwevt_handler - Common FW event handler routine.
 * @hw: HW module.
 *
 * This is the ISR for FW events. It is shared b/w MSIX
 * and INTx handlers.
 */
static void
csio_fwevt_handler(struct csio_hw *hw)
{
        int rv;
        unsigned long flags;

        rv = csio_fwevtq_handler(hw);

        spin_lock_irqsave(&hw->lock, flags);
        if (rv == 0 && !(hw->flags & CSIO_HWF_FWEVT_PENDING)) {
                hw->flags |= CSIO_HWF_FWEVT_PENDING;
                spin_unlock_irqrestore(&hw->lock, flags);
                schedule_work(&hw->evtq_work);
                return;
        }
        spin_unlock_irqrestore(&hw->lock, flags);

} /* csio_fwevt_handler */

/*
 * csio_fwevt_isr() - FW events MSIX ISR
 * @irq:
 * @dev_id:
 *
 * Process WRs on the FW event queue.
 *
 */
static irqreturn_t
csio_fwevt_isr(int irq, void *dev_id)
{
        struct csio_hw *hw = (struct csio_hw *) dev_id;

        if (unlikely(!hw))
                return IRQ_NONE;

        if (unlikely(pci_channel_offline(hw->pdev))) {
                CSIO_INC_STATS(hw, n_pcich_offline);
                return IRQ_NONE;
        }

        csio_fwevt_handler(hw);

        return IRQ_HANDLED;
}

/*
 * csio_fwevt_isr() - INTx wrapper for handling FW events.
 * @irq:
 * @dev_id:
 */
void
csio_fwevt_intx_handler(struct csio_hw *hw, void *wr, uint32_t len,
                           struct csio_fl_dma_buf *flb, void *priv)
{
        csio_fwevt_handler(hw);
} /* csio_fwevt_intx_handler */

/*
 * csio_process_scsi_cmpl - Process a SCSI WR completion.
 * @hw: HW module.
 * @wr: The completed WR from the ingress queue.
 * @len: Length of the WR.
 * @flb: Freelist buffer array.
 *
 */
static void
csio_process_scsi_cmpl(struct csio_hw *hw, void *wr, uint32_t len,
                        struct csio_fl_dma_buf *flb, void *cbfn_q)
{
        struct csio_ioreq *ioreq;
        uint8_t *scsiwr;
        uint8_t subop;
        void *cmnd;
        unsigned long flags;

        ioreq = csio_scsi_cmpl_handler(hw, wr, len, flb, NULL, &scsiwr);
        if (likely(ioreq)) {
                if (unlikely(*scsiwr == FW_SCSI_ABRT_CLS_WR)) {
                        subop = FW_SCSI_ABRT_CLS_WR_SUB_OPCODE_GET(
                                        ((struct fw_scsi_abrt_cls_wr *)
                                            scsiwr)->sub_opcode_to_chk_all_io);

                        csio_dbg(hw, "%s cmpl recvd ioreq:%p status:%d\n",
                                    subop ? "Close" : "Abort",
                                    ioreq, ioreq->wr_status);

                        spin_lock_irqsave(&hw->lock, flags);
                        if (subop)
                                csio_scsi_closed(ioreq,
                                                 (struct list_head *)cbfn_q);
                        else
                                csio_scsi_aborted(ioreq,
                                                  (struct list_head *)cbfn_q);
                        /*
                         * We call scsi_done for I/Os that driver thinks aborts
                         * have timed out. If there is a race caused by FW
                         * completing abort at the exact same time that the
                         * driver has deteced the abort timeout, the following
                         * check prevents calling of scsi_done twice for the
                         * same command: once from the eh_abort_handler, another
                         * from csio_scsi_isr_handler(). This also avoids the
                         * need to check if csio_scsi_cmnd(req) is NULL in the
                         * fast path.
                         */
                        cmnd = csio_scsi_cmnd(ioreq);
                        if (unlikely(cmnd == NULL))
                                list_del_init(&ioreq->sm.sm_list);

                        spin_unlock_irqrestore(&hw->lock, flags);

                        if (unlikely(cmnd == NULL))
                                csio_put_scsi_ioreq_lock(hw,
                                                csio_hw_to_scsim(hw), ioreq);
                } else {
                        spin_lock_irqsave(&hw->lock, flags);
                        csio_scsi_completed(ioreq, (struct list_head *)cbfn_q);
                        spin_unlock_irqrestore(&hw->lock, flags);
                }
        }
}

/*
 * csio_scsi_isr_handler() - Common SCSI ISR handler.
 * @iq: Ingress queue pointer.
 *
 * Processes SCSI completions on the SCSI IQ indicated by scm->iq_idx
 * by calling csio_wr_process_iq_idx. If there are completions on the
 * isr_cbfn_q, yank them out into a local queue and call their io_cbfns.
 * Once done, add these completions onto the freelist.
 * This routine is shared b/w MSIX and INTx.
 */
static inline irqreturn_t
csio_scsi_isr_handler(struct csio_q *iq)
{
        struct csio_hw *hw = (struct csio_hw *)iq->owner;
        LIST_HEAD(cbfn_q);
        struct list_head *tmp;
        struct csio_scsim *scm;
        struct csio_ioreq *ioreq;
        int isr_completions = 0;

        scm = csio_hw_to_scsim(hw);

        if (unlikely(csio_wr_process_iq(hw, iq, csio_process_scsi_cmpl,
                                        &cbfn_q) != 0))
                return IRQ_NONE;

        /* Call back the completion routines */
        list_for_each(tmp, &cbfn_q) {
                ioreq = (struct csio_ioreq *)tmp;
                isr_completions++;
                ioreq->io_cbfn(hw, ioreq);
                /* Release ddp buffer if used for this req */
                if (unlikely(ioreq->dcopy))
                        csio_put_scsi_ddp_list_lock(hw, scm, &ioreq->gen_list,
                                                    ioreq->nsge);
        }

        if (isr_completions) {
                /* Return the ioreqs back to ioreq->freelist */
                csio_put_scsi_ioreq_list_lock(hw, scm, &cbfn_q,
                                              isr_completions);
        }

        return IRQ_HANDLED;
}

/*
 * csio_scsi_isr() - SCSI MSIX handler
 * @irq:
 * @dev_id:
 *
 * This is the top level SCSI MSIX handler. Calls csio_scsi_isr_handler()
 * for handling SCSI completions.
 */
static irqreturn_t
csio_scsi_isr(int irq, void *dev_id)
{
        struct csio_q *iq = (struct csio_q *) dev_id;
        struct csio_hw *hw;

        if (unlikely(!iq))
                return IRQ_NONE;

        hw = (struct csio_hw *)iq->owner;

        if (unlikely(pci_channel_offline(hw->pdev))) {
                CSIO_INC_STATS(hw, n_pcich_offline);
                return IRQ_NONE;
        }

        csio_scsi_isr_handler(iq);

        return IRQ_HANDLED;
}

/*
 * csio_scsi_intx_handler() - SCSI INTx handler
 * @irq:
 * @dev_id:
 *
 * This is the top level SCSI INTx handler. Calls csio_scsi_isr_handler()
 * for handling SCSI completions.
 */
void
csio_scsi_intx_handler(struct csio_hw *hw, void *wr, uint32_t len,
                        struct csio_fl_dma_buf *flb, void *priv)
{
        struct csio_q *iq = priv;

        csio_scsi_isr_handler(iq);

} /* csio_scsi_intx_handler */

/*
 * csio_fcoe_isr() - INTx/MSI interrupt service routine for FCoE.
 * @irq:
 * @dev_id:
 *
 *
 */
static irqreturn_t
csio_fcoe_isr(int irq, void *dev_id)
{
        struct csio_hw *hw = (struct csio_hw *) dev_id;
        struct csio_q *intx_q = NULL;
        int rv;
        irqreturn_t ret = IRQ_NONE;
        unsigned long flags;

        if (unlikely(!hw))
                return IRQ_NONE;

        if (unlikely(pci_channel_offline(hw->pdev))) {
                CSIO_INC_STATS(hw, n_pcich_offline);
                return IRQ_NONE;
        }

        /* Disable the interrupt for this PCI function. */
        if (hw->intr_mode == CSIO_IM_INTX)
                csio_wr_reg32(hw, 0, MYPF_REG(PCIE_PF_CLI_A));

        /*
         * The read in the following function will flush the
         * above write.
         */
        if (csio_hw_slow_intr_handler(hw))
                ret = IRQ_HANDLED;

        /* Get the INTx Forward interrupt IQ. */
        intx_q = csio_get_q(hw, hw->intr_iq_idx);

        CSIO_DB_ASSERT(intx_q);

        /* IQ handler is not possible for intx_q, hence pass in NULL */
        if (likely(csio_wr_process_iq(hw, intx_q, NULL, NULL) == 0))
                ret = IRQ_HANDLED;

        spin_lock_irqsave(&hw->lock, flags);
        rv = csio_mb_isr_handler(hw);
        if (rv == 0 && !(hw->flags & CSIO_HWF_FWEVT_PENDING)) {
                hw->flags |= CSIO_HWF_FWEVT_PENDING;
                spin_unlock_irqrestore(&hw->lock, flags);
                schedule_work(&hw->evtq_work);
                return IRQ_HANDLED;
        }
        spin_unlock_irqrestore(&hw->lock, flags);

        return ret;
}

static void
csio_add_msix_desc(struct csio_hw *hw)
{
        int i;
        struct csio_msix_entries *entryp = &hw->msix_entries[0];
        int k = CSIO_EXTRA_VECS;
        int len = sizeof(entryp->desc) - 1;
        int cnt = hw->num_sqsets + k;

        /* Non-data vector */
        memset(entryp->desc, 0, len + 1);
        snprintf(entryp->desc, len, "csio-%02x:%02x:%x-nondata",
                 CSIO_PCI_BUS(hw), CSIO_PCI_DEV(hw), CSIO_PCI_FUNC(hw));

        entryp++;
        memset(entryp->desc, 0, len + 1);
        snprintf(entryp->desc, len, "csio-%02x:%02x:%x-fwevt",
                 CSIO_PCI_BUS(hw), CSIO_PCI_DEV(hw), CSIO_PCI_FUNC(hw));
        entryp++;

        /* Name SCSI vecs */
        for (i = k; i < cnt; i++, entryp++) {
                memset(entryp->desc, 0, len + 1);
                snprintf(entryp->desc, len, "csio-%02x:%02x:%x-scsi%d",
                         CSIO_PCI_BUS(hw), CSIO_PCI_DEV(hw),
                         CSIO_PCI_FUNC(hw), i - CSIO_EXTRA_VECS);
        }
}

int
csio_request_irqs(struct csio_hw *hw)
{
        int rv, i, j, k = 0;
        struct csio_msix_entries *entryp = &hw->msix_entries[0];
        struct csio_scsi_cpu_info *info;
        struct pci_dev *pdev = hw->pdev;

        if (hw->intr_mode != CSIO_IM_MSIX) {
                rv = request_irq(pci_irq_vector(pdev, 0), csio_fcoe_isr,
                                hw->intr_mode == CSIO_IM_MSI ? 0 : IRQF_SHARED,
                                KBUILD_MODNAME, hw);
                if (rv) {
                        csio_err(hw, "Failed to allocate interrupt line.\n");
                        goto out_free_irqs;
                }

                goto out;
        }

        /* Add the MSIX vector descriptions */
        csio_add_msix_desc(hw);

        rv = request_irq(pci_irq_vector(pdev, k), csio_nondata_isr, 0,
                         entryp[k].desc, hw);
        if (rv) {
                csio_err(hw, "IRQ request failed for vec %d err:%d\n",
                         pci_irq_vector(pdev, k), rv);
                goto out_free_irqs;
        }

        entryp[k++].dev_id = hw;

        rv = request_irq(pci_irq_vector(pdev, k), csio_fwevt_isr, 0,
                         entryp[k].desc, hw);
        if (rv) {
                csio_err(hw, "IRQ request failed for vec %d err:%d\n",
                         pci_irq_vector(pdev, k), rv);
                goto out_free_irqs;
        }

        entryp[k++].dev_id = (void *)hw;

        /* Allocate IRQs for SCSI */
        for (i = 0; i < hw->num_pports; i++) {
                info = &hw->scsi_cpu_info[i];
                for (j = 0; j < info->max_cpus; j++, k++) {
                        struct csio_scsi_qset *sqset = &hw->sqset[i][j];
                        struct csio_q *q = hw->wrm.q_arr[sqset->iq_idx];

                        rv = request_irq(pci_irq_vector(pdev, k), csio_scsi_isr, 0,
                                         entryp[k].desc, q);
                        if (rv) {
                                csio_err(hw,
                                       "IRQ request failed for vec %d err:%d\n",
                                       pci_irq_vector(pdev, k), rv);
                                goto out_free_irqs;
                        }

                        entryp[k].dev_id = q;

                } /* for all scsi cpus */
        } /* for all ports */

out:
        hw->flags |= CSIO_HWF_HOST_INTR_ENABLED;
        return 0;

out_free_irqs:
        for (i = 0; i < k; i++)
                free_irq(pci_irq_vector(pdev, i), hw->msix_entries[i].dev_id);
        pci_free_irq_vectors(hw->pdev);
        return -EINVAL;
}

/* Reduce per-port max possible CPUs */
static void
csio_reduce_sqsets(struct csio_hw *hw, int cnt)
{
        int i;
        struct csio_scsi_cpu_info *info;

        while (cnt < hw->num_sqsets) {
                for (i = 0; i < hw->num_pports; i++) {
                        info = &hw->scsi_cpu_info[i];
                        if (info->max_cpus > 1) {
                                info->max_cpus--;
                                hw->num_sqsets--;
                                if (hw->num_sqsets <= cnt)
                                        break;
                        }
                }
        }

        csio_dbg(hw, "Reduced sqsets to %d\n", hw->num_sqsets);
}

static int
csio_enable_msix(struct csio_hw *hw)
{
        int i, j, k, n, min, cnt;
        int extra = CSIO_EXTRA_VECS;
        struct csio_scsi_cpu_info *info;
        struct irq_affinity desc = { .pre_vectors = 2 };

        min = hw->num_pports + extra;
        cnt = hw->num_sqsets + extra;

        /* Max vectors required based on #niqs configured in fw */
        if (hw->flags & CSIO_HWF_USING_SOFT_PARAMS || !csio_is_hw_master(hw))
                cnt = min_t(uint8_t, hw->cfg_niq, cnt);

        csio_dbg(hw, "FW supp #niq:%d, trying %d msix's\n", hw->cfg_niq, cnt);

        cnt = pci_alloc_irq_vectors_affinity(hw->pdev, min, cnt,
                        PCI_IRQ_MSIX | PCI_IRQ_AFFINITY, &desc);
        if (cnt < 0)
                return cnt;

        if (cnt < (hw->num_sqsets + extra)) {
                csio_dbg(hw, "Reducing sqsets to %d\n", cnt - extra);
                csio_reduce_sqsets(hw, cnt - extra);
        }

        /* Distribute vectors */
        k = 0;
        csio_set_nondata_intr_idx(hw, k);
        csio_set_mb_intr_idx(csio_hw_to_mbm(hw), k++);
        csio_set_fwevt_intr_idx(hw, k++);

        for (i = 0; i < hw->num_pports; i++) {
                info = &hw->scsi_cpu_info[i];

                for (j = 0; j < hw->num_scsi_msix_cpus; j++) {
                        n = (j % info->max_cpus) +  k;
                        hw->sqset[i][j].intr_idx = n;
                }

                k += info->max_cpus;
        }

        return 0;
}

void
csio_intr_enable(struct csio_hw *hw)
{
        hw->intr_mode = CSIO_IM_NONE;
        hw->flags &= ~CSIO_HWF_HOST_INTR_ENABLED;

        /* Try MSIX, then MSI or fall back to INTx */
        if ((csio_msi == 2) && !csio_enable_msix(hw))
                hw->intr_mode = CSIO_IM_MSIX;
        else {
                /* Max iqs required based on #niqs configured in fw */
                if (hw->flags & CSIO_HWF_USING_SOFT_PARAMS ||
                        !csio_is_hw_master(hw)) {
                        int extra = CSIO_EXTRA_MSI_IQS;

                        if (hw->cfg_niq < (hw->num_sqsets + extra)) {
                                csio_dbg(hw, "Reducing sqsets to %d\n",
                                         hw->cfg_niq - extra);
                                csio_reduce_sqsets(hw, hw->cfg_niq - extra);
                        }
                }

                if ((csio_msi == 1) && !pci_enable_msi(hw->pdev))
                        hw->intr_mode = CSIO_IM_MSI;
                else
                        hw->intr_mode = CSIO_IM_INTX;
        }

        csio_dbg(hw, "Using %s interrupt mode.\n",
                (hw->intr_mode == CSIO_IM_MSIX) ? "MSIX" :
                ((hw->intr_mode == CSIO_IM_MSI) ? "MSI" : "INTx"));
}

void
csio_intr_disable(struct csio_hw *hw, bool free)
{
        csio_hw_intr_disable(hw);

        if (free) {
                int i;

                switch (hw->intr_mode) {
                case CSIO_IM_MSIX:
                        for (i = 0; i < hw->num_sqsets + CSIO_EXTRA_VECS; i++) {
                                free_irq(pci_irq_vector(hw->pdev, i),
                                         hw->msix_entries[i].dev_id);
                        }
                        break;
                case CSIO_IM_MSI:
                case CSIO_IM_INTX:
                        free_irq(pci_irq_vector(hw->pdev, 0), hw);
                        break;
                default:
                        break;
                }
        }

        pci_free_irq_vectors(hw->pdev);
        hw->intr_mode = CSIO_IM_NONE;
        hw->flags &= ~CSIO_HWF_HOST_INTR_ENABLED;
}