/*
 * Copyright 2014 Cisco Systems, Inc.  All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * 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/string.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/interrupt.h>

#include "vnic_dev.h"
#include "vnic_intr.h"
#include "vnic_stats.h"
#include "snic_io.h"
#include "snic.h"


/*
 * snic_isr_msix_wq : MSIx ISR for work queue.
 */

static irqreturn_t
snic_isr_msix_wq(int irq, void *data)
{
        struct snic *snic = data;
        unsigned long wq_work_done = 0;

        snic->s_stats.misc.last_isr_time = jiffies;
        atomic64_inc(&snic->s_stats.misc.ack_isr_cnt);

        wq_work_done = snic_wq_cmpl_handler(snic, -1);
        svnic_intr_return_credits(&snic->intr[SNIC_MSIX_WQ],
                                  wq_work_done,
                                  1 /* unmask intr */,
                                  1 /* reset intr timer */);

        return IRQ_HANDLED;
} /* end of snic_isr_msix_wq */

static irqreturn_t
snic_isr_msix_io_cmpl(int irq, void *data)
{
        struct snic *snic = data;
        unsigned long iocmpl_work_done = 0;

        snic->s_stats.misc.last_isr_time = jiffies;
        atomic64_inc(&snic->s_stats.misc.cmpl_isr_cnt);

        iocmpl_work_done = snic_fwcq_cmpl_handler(snic, -1);
        svnic_intr_return_credits(&snic->intr[SNIC_MSIX_IO_CMPL],
                                  iocmpl_work_done,
                                  1 /* unmask intr */,
                                  1 /* reset intr timer */);

        return IRQ_HANDLED;
} /* end of snic_isr_msix_io_cmpl */

static irqreturn_t
snic_isr_msix_err_notify(int irq, void *data)
{
        struct snic *snic = data;

        snic->s_stats.misc.last_isr_time = jiffies;
        atomic64_inc(&snic->s_stats.misc.errnotify_isr_cnt);

        svnic_intr_return_all_credits(&snic->intr[SNIC_MSIX_ERR_NOTIFY]);
        snic_log_q_error(snic);

        /*Handling link events */
        snic_handle_link_event(snic);

        return IRQ_HANDLED;
} /* end of snic_isr_msix_err_notify */


void
snic_free_intr(struct snic *snic)
{
        int i;

        /* ONLY interrupt mode MSIX is supported */
        for (i = 0; i < ARRAY_SIZE(snic->msix); i++) {
                if (snic->msix[i].requested) {
                        free_irq(pci_irq_vector(snic->pdev, i),
                                 snic->msix[i].devid);
                }
        }
} /* end of snic_free_intr */

int
snic_request_intr(struct snic *snic)
{
        int ret = 0, i;
        enum vnic_dev_intr_mode intr_mode;

        intr_mode = svnic_dev_get_intr_mode(snic->vdev);
        SNIC_BUG_ON(intr_mode != VNIC_DEV_INTR_MODE_MSIX);

        /*
         * Currently HW supports single WQ and CQ. So passing devid as snic.
         * When hardware supports multiple WQs and CQs, one idea is
         * to pass devid as corresponding WQ or CQ ptr and retrieve snic
         * from queue ptr.
         * Except for err_notify, which is always one.
         */
        sprintf(snic->msix[SNIC_MSIX_WQ].devname,
                "%.11s-scsi-wq",
                snic->name);
        snic->msix[SNIC_MSIX_WQ].isr = snic_isr_msix_wq;
        snic->msix[SNIC_MSIX_WQ].devid = snic;

        sprintf(snic->msix[SNIC_MSIX_IO_CMPL].devname,
                "%.11s-io-cmpl",
                snic->name);
        snic->msix[SNIC_MSIX_IO_CMPL].isr = snic_isr_msix_io_cmpl;
        snic->msix[SNIC_MSIX_IO_CMPL].devid = snic;

        sprintf(snic->msix[SNIC_MSIX_ERR_NOTIFY].devname,
                "%.11s-err-notify",
                snic->name);
        snic->msix[SNIC_MSIX_ERR_NOTIFY].isr = snic_isr_msix_err_notify;
        snic->msix[SNIC_MSIX_ERR_NOTIFY].devid = snic;

        for (i = 0; i < ARRAY_SIZE(snic->msix); i++) {
                ret = request_irq(pci_irq_vector(snic->pdev, i),
                                  snic->msix[i].isr,
                                  0,
                                  snic->msix[i].devname,
                                  snic->msix[i].devid);
                if (ret) {
                        SNIC_HOST_ERR(snic->shost,
                                      "MSI-X: request_irq(%d) failed %d\n",
                                      i,
                                      ret);
                        snic_free_intr(snic);
                        break;
                }
                snic->msix[i].requested = 1;
        }

        return ret;
} /* end of snic_request_intr */

int
snic_set_intr_mode(struct snic *snic)
{
        unsigned int n = ARRAY_SIZE(snic->wq);
        unsigned int m = SNIC_CQ_IO_CMPL_MAX;
        unsigned int vecs = n + m + 1;

        /*
         * We need n WQs, m CQs, and n+m+1 INTRs
         * (last INTR is used for WQ/CQ errors and notification area
         */
        BUILD_BUG_ON((ARRAY_SIZE(snic->wq) + SNIC_CQ_IO_CMPL_MAX) >
                        ARRAY_SIZE(snic->intr));

        if (snic->wq_count < n || snic->cq_count < n + m)
                goto fail;

        if (pci_alloc_irq_vectors(snic->pdev, vecs, vecs, PCI_IRQ_MSIX) < 0)
                goto fail;

        snic->wq_count = n;
        snic->cq_count = n + m;
        snic->intr_count = vecs;
        snic->err_intr_offset = SNIC_MSIX_ERR_NOTIFY;

        SNIC_ISR_DBG(snic->shost, "Using MSI-X Interrupts\n");
        svnic_dev_set_intr_mode(snic->vdev, VNIC_DEV_INTR_MODE_MSIX);
        return 0;
fail:
        svnic_dev_set_intr_mode(snic->vdev, VNIC_DEV_INTR_MODE_UNKNOWN);
        return -EINVAL;
} /* end of snic_set_intr_mode */

void
snic_clear_intr_mode(struct snic *snic)
{
        pci_free_irq_vectors(snic->pdev);
        svnic_dev_set_intr_mode(snic->vdev, VNIC_DEV_INTR_MODE_INTX);
}