/*
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 *   redistributing this file, you may do so under either license.
 *
 *   GPL LICENSE SUMMARY
 *
 *   Copyright(c) 2012 Intel Corporation. All rights reserved.
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of version 2 of the GNU General Public License as
 *   published by the Free Software Foundation.
 *
 *   BSD LICENSE
 *
 *   Copyright(c) 2012 Intel Corporation. All rights reserved.
 *
 *   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 copy
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Intel PCIe NTB Linux driver
 *
 * Contact Information:
 * Jon Mason <jon.mason@intel.com>
 */
#include <linux/debugfs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include "ntb_hw.h"
#include "ntb_regs.h"

#define NTB_NAME        "Intel(R) PCI-E Non-Transparent Bridge Driver"
#define NTB_VER         "0.25"

MODULE_DESCRIPTION(NTB_NAME);
MODULE_VERSION(NTB_VER);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Intel Corporation");

enum {
        NTB_CONN_CLASSIC = 0,
        NTB_CONN_B2B,
        NTB_CONN_RP,
};

enum {
        NTB_DEV_USD = 0,
        NTB_DEV_DSD,
};

enum {
        SNB_HW = 0,
        BWD_HW,
};

/* Translate memory window 0,1 to BAR 2,4 */
#define MW_TO_BAR(mw)   (mw * 2 + 2)

static DEFINE_PCI_DEVICE_TABLE(ntb_pci_tbl) = {
        {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_BWD)},
        {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_JSF)},
        {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_CLASSIC_JSF)},
        {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_RP_JSF)},
        {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_RP_SNB)},
        {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_SNB)},
        {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_CLASSIC_SNB)},
        {0}
};
MODULE_DEVICE_TABLE(pci, ntb_pci_tbl);

/**
 * ntb_register_event_callback() - register event callback
 * @ndev: pointer to ntb_device instance
 * @func: callback function to register
 *
 * This function registers a callback for any HW driver events such as link
 * up/down, power management notices and etc.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int ntb_register_event_callback(struct ntb_device *ndev,
                            void (*func)(void *handle, enum ntb_hw_event event))
{
        if (ndev->event_cb)
                return -EINVAL;

        ndev->event_cb = func;

        return 0;
}

/**
 * ntb_unregister_event_callback() - unregisters the event callback
 * @ndev: pointer to ntb_device instance
 *
 * This function unregisters the existing callback from transport
 */
void ntb_unregister_event_callback(struct ntb_device *ndev)
{
        ndev->event_cb = NULL;
}

/**
 * ntb_register_db_callback() - register a callback for doorbell interrupt
 * @ndev: pointer to ntb_device instance
 * @idx: doorbell index to register callback, zero based
 * @func: callback function to register
 *
 * This function registers a callback function for the doorbell interrupt
 * on the primary side. The function will unmask the doorbell as well to
 * allow interrupt.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
                             void *data, void (*func)(void *data, int db_num))
{
        unsigned long mask;

        if (idx >= ndev->max_cbs || ndev->db_cb[idx].callback) {
                dev_warn(&ndev->pdev->dev, "Invalid Index.\n");
                return -EINVAL;
        }

        ndev->db_cb[idx].callback = func;
        ndev->db_cb[idx].data = data;

        /* unmask interrupt */
        mask = readw(ndev->reg_ofs.pdb_mask);
        clear_bit(idx * ndev->bits_per_vector, &mask);
        writew(mask, ndev->reg_ofs.pdb_mask);

        return 0;
}

/**
 * ntb_unregister_db_callback() - unregister a callback for doorbell interrupt
 * @ndev: pointer to ntb_device instance
 * @idx: doorbell index to register callback, zero based
 *
 * This function unregisters a callback function for the doorbell interrupt
 * on the primary side. The function will also mask the said doorbell.
 */
void ntb_unregister_db_callback(struct ntb_device *ndev, unsigned int idx)
{
        unsigned long mask;

        if (idx >= ndev->max_cbs || !ndev->db_cb[idx].callback)
                return;

        mask = readw(ndev->reg_ofs.pdb_mask);
        set_bit(idx * ndev->bits_per_vector, &mask);
        writew(mask, ndev->reg_ofs.pdb_mask);

        ndev->db_cb[idx].callback = NULL;
}

/**
 * ntb_find_transport() - find the transport pointer
 * @transport: pointer to pci device
 *
 * Given the pci device pointer, return the transport pointer passed in when
 * the transport attached when it was inited.
 *
 * RETURNS: pointer to transport.
 */
void *ntb_find_transport(struct pci_dev *pdev)
{
        struct ntb_device *ndev = pci_get_drvdata(pdev);
        return ndev->ntb_transport;
}

/**
 * ntb_register_transport() - Register NTB transport with NTB HW driver
 * @transport: transport identifier
 *
 * This function allows a transport to reserve the hardware driver for
 * NTB usage.
 *
 * RETURNS: pointer to ntb_device, NULL on error.
 */
struct ntb_device *ntb_register_transport(struct pci_dev *pdev, void *transport)
{
        struct ntb_device *ndev = pci_get_drvdata(pdev);

        if (ndev->ntb_transport)
                return NULL;

        ndev->ntb_transport = transport;
        return ndev;
}

/**
 * ntb_unregister_transport() - Unregister the transport with the NTB HW driver
 * @ndev - ntb_device of the transport to be freed
 *
 * This function unregisters the transport from the HW driver and performs any
 * necessary cleanups.
 */
void ntb_unregister_transport(struct ntb_device *ndev)
{
        int i;

        if (!ndev->ntb_transport)
                return;

        for (i = 0; i < ndev->max_cbs; i++)
                ntb_unregister_db_callback(ndev, i);

        ntb_unregister_event_callback(ndev);
        ndev->ntb_transport = NULL;
}

/**
 * ntb_write_local_spad() - write to the secondary scratchpad register
 * @ndev: pointer to ntb_device instance
 * @idx: index to the scratchpad register, 0 based
 * @val: the data value to put into the register
 *
 * This function allows writing of a 32bit value to the indexed scratchpad
 * register. This writes over the data mirrored to the local scratchpad register
 * by the remote system.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int ntb_write_local_spad(struct ntb_device *ndev, unsigned int idx, u32 val)
{
        if (idx >= ndev->limits.max_spads)
                return -EINVAL;

        dev_dbg(&ndev->pdev->dev, "Writing %x to local scratch pad index %d\n",
                val, idx);
        writel(val, ndev->reg_ofs.spad_read + idx * 4);

        return 0;
}

/**
 * ntb_read_local_spad() - read from the primary scratchpad register
 * @ndev: pointer to ntb_device instance
 * @idx: index to scratchpad register, 0 based
 * @val: pointer to 32bit integer for storing the register value
 *
 * This function allows reading of the 32bit scratchpad register on
 * the primary (internal) side.  This allows the local system to read data
 * written and mirrored to the scratchpad register by the remote system.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int ntb_read_local_spad(struct ntb_device *ndev, unsigned int idx, u32 *val)
{
        if (idx >= ndev->limits.max_spads)
                return -EINVAL;

        *val = readl(ndev->reg_ofs.spad_write + idx * 4);
        dev_dbg(&ndev->pdev->dev,
                "Reading %x from local scratch pad index %d\n", *val, idx);

        return 0;
}

/**
 * ntb_write_remote_spad() - write to the secondary scratchpad register
 * @ndev: pointer to ntb_device instance
 * @idx: index to the scratchpad register, 0 based
 * @val: the data value to put into the register
 *
 * This function allows writing of a 32bit value to the indexed scratchpad
 * register. The register resides on the secondary (external) side.  This allows
 * the local system to write data to be mirrored to the remote systems
 * scratchpad register.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int ntb_write_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 val)
{
        if (idx >= ndev->limits.max_spads)
                return -EINVAL;

        dev_dbg(&ndev->pdev->dev, "Writing %x to remote scratch pad index %d\n",
                val, idx);
        writel(val, ndev->reg_ofs.spad_write + idx * 4);

        return 0;
}

/**
 * ntb_read_remote_spad() - read from the primary scratchpad register
 * @ndev: pointer to ntb_device instance
 * @idx: index to scratchpad register, 0 based
 * @val: pointer to 32bit integer for storing the register value
 *
 * This function allows reading of the 32bit scratchpad register on
 * the primary (internal) side.  This alloows the local system to read the data
 * it wrote to be mirrored on the remote system.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val)
{
        if (idx >= ndev->limits.max_spads)
                return -EINVAL;

        *val = readl(ndev->reg_ofs.spad_read + idx * 4);
        dev_dbg(&ndev->pdev->dev,
                "Reading %x from remote scratch pad index %d\n", *val, idx);

        return 0;
}

/**
 * ntb_get_mw_vbase() - get virtual addr for the NTB memory window
 * @ndev: pointer to ntb_device instance
 * @mw: memory window number
 *
 * This function provides the base virtual address of the memory window
 * specified.
 *
 * RETURNS: pointer to virtual address, or NULL on error.
 */
void __iomem *ntb_get_mw_vbase(struct ntb_device *ndev, unsigned int mw)
{
        if (mw >= NTB_NUM_MW)
                return NULL;

        return ndev->mw[mw].vbase;
}

/**
 * ntb_get_mw_size() - return size of NTB memory window
 * @ndev: pointer to ntb_device instance
 * @mw: memory window number
 *
 * This function provides the physical size of the memory window specified
 *
 * RETURNS: the size of the memory window or zero on error
 */
resource_size_t ntb_get_mw_size(struct ntb_device *ndev, unsigned int mw)
{
        if (mw >= NTB_NUM_MW)
                return 0;

        return ndev->mw[mw].bar_sz;
}

/**
 * ntb_set_mw_addr - set the memory window address
 * @ndev: pointer to ntb_device instance
 * @mw: memory window number
 * @addr: base address for data
 *
 * This function sets the base physical address of the memory window.  This
 * memory address is where data from the remote system will be transfered into
 * or out of depending on how the transport is configured.
 */
void ntb_set_mw_addr(struct ntb_device *ndev, unsigned int mw, u64 addr)
{
        if (mw >= NTB_NUM_MW)
                return;

        dev_dbg(&ndev->pdev->dev, "Writing addr %Lx to BAR %d\n", addr,
                MW_TO_BAR(mw));

        ndev->mw[mw].phys_addr = addr;

        switch (MW_TO_BAR(mw)) {
        case NTB_BAR_23:
                writeq(addr, ndev->reg_ofs.sbar2_xlat);
                break;
        case NTB_BAR_45:
                writeq(addr, ndev->reg_ofs.sbar4_xlat);
                break;
        }
}

/**
 * ntb_ring_sdb() - Set the doorbell on the secondary/external side
 * @ndev: pointer to ntb_device instance
 * @db: doorbell to ring
 *
 * This function allows triggering of a doorbell on the secondary/external
 * side that will initiate an interrupt on the remote host
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
void ntb_ring_sdb(struct ntb_device *ndev, unsigned int db)
{
        dev_dbg(&ndev->pdev->dev, "%s: ringing doorbell %d\n", __func__, db);

        if (ndev->hw_type == BWD_HW)
                writeq((u64) 1 << db, ndev->reg_ofs.sdb);
        else
                writew(((1 << ndev->bits_per_vector) - 1) <<
                       (db * ndev->bits_per_vector), ndev->reg_ofs.sdb);
}

static void ntb_link_event(struct ntb_device *ndev, int link_state)
{
        unsigned int event;

        if (ndev->link_status == link_state)
                return;

        if (link_state == NTB_LINK_UP) {
                u16 status;

                dev_info(&ndev->pdev->dev, "Link Up\n");
                ndev->link_status = NTB_LINK_UP;
                event = NTB_EVENT_HW_LINK_UP;

                if (ndev->hw_type == BWD_HW)
                        status = readw(ndev->reg_ofs.lnk_stat);
                else {
                        int rc = pci_read_config_word(ndev->pdev,
                                                      SNB_LINK_STATUS_OFFSET,
                                                      &status);
                        if (rc)
                                return;
                }
                dev_info(&ndev->pdev->dev, "Link Width %d, Link Speed %d\n",
                         (status & NTB_LINK_WIDTH_MASK) >> 4,
                         (status & NTB_LINK_SPEED_MASK));
        } else {
                dev_info(&ndev->pdev->dev, "Link Down\n");
                ndev->link_status = NTB_LINK_DOWN;
                event = NTB_EVENT_HW_LINK_DOWN;
        }

        /* notify the upper layer if we have an event change */
        if (ndev->event_cb)
                ndev->event_cb(ndev->ntb_transport, event);
}

static int ntb_link_status(struct ntb_device *ndev)
{
        int link_state;

        if (ndev->hw_type == BWD_HW) {
                u32 ntb_cntl;

                ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
                if (ntb_cntl & BWD_CNTL_LINK_DOWN)
                        link_state = NTB_LINK_DOWN;
                else
                        link_state = NTB_LINK_UP;
        } else {
                u16 status;
                int rc;

                rc = pci_read_config_word(ndev->pdev, SNB_LINK_STATUS_OFFSET,
                                          &status);
                if (rc)
                        return rc;

                if (status & NTB_LINK_STATUS_ACTIVE)
                        link_state = NTB_LINK_UP;
                else
                        link_state = NTB_LINK_DOWN;
        }

        ntb_link_event(ndev, link_state);

        return 0;
}

/* BWD doesn't have link status interrupt, poll on that platform */
static void bwd_link_poll(struct work_struct *work)
{
        struct ntb_device *ndev = container_of(work, struct ntb_device,
                                               hb_timer.work);
        unsigned long ts = jiffies;

        /* If we haven't gotten an interrupt in a while, check the BWD link
         * status bit
         */
        if (ts > ndev->last_ts + NTB_HB_TIMEOUT) {
                int rc = ntb_link_status(ndev);
                if (rc)
                        dev_err(&ndev->pdev->dev,
                                "Error determining link status\n");
        }

        schedule_delayed_work(&ndev->hb_timer, NTB_HB_TIMEOUT);
}

static int ntb_xeon_setup(struct ntb_device *ndev)
{
        int rc;
        u8 val;

        ndev->hw_type = SNB_HW;

        rc = pci_read_config_byte(ndev->pdev, NTB_PPD_OFFSET, &val);
        if (rc)
                return rc;

        switch (val & SNB_PPD_CONN_TYPE) {
        case NTB_CONN_B2B:
                ndev->conn_type = NTB_CONN_B2B;
                break;
        case NTB_CONN_CLASSIC:
        case NTB_CONN_RP:
        default:
                dev_err(&ndev->pdev->dev, "Only B2B supported at this time\n");
                return -EINVAL;
        }

        if (val & SNB_PPD_DEV_TYPE)
                ndev->dev_type = NTB_DEV_DSD;
        else
                ndev->dev_type = NTB_DEV_USD;

        ndev->reg_ofs.pdb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
        ndev->reg_ofs.pdb_mask = ndev->reg_base + SNB_PDBMSK_OFFSET;
        ndev->reg_ofs.sbar2_xlat = ndev->reg_base + SNB_SBAR2XLAT_OFFSET;
        ndev->reg_ofs.sbar4_xlat = ndev->reg_base + SNB_SBAR4XLAT_OFFSET;
        ndev->reg_ofs.lnk_cntl = ndev->reg_base + SNB_NTBCNTL_OFFSET;
        ndev->reg_ofs.lnk_stat = ndev->reg_base + SNB_LINK_STATUS_OFFSET;
        ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET;
        ndev->reg_ofs.spci_cmd = ndev->reg_base + SNB_PCICMD_OFFSET;

        if (ndev->conn_type == NTB_CONN_B2B) {
                ndev->reg_ofs.sdb = ndev->reg_base + SNB_B2B_DOORBELL_OFFSET;
                ndev->reg_ofs.spad_write = ndev->reg_base + SNB_B2B_SPAD_OFFSET;
                ndev->limits.max_spads = SNB_MAX_SPADS;
        } else {
                ndev->reg_ofs.sdb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
                ndev->reg_ofs.spad_write = ndev->reg_base + SNB_SPAD_OFFSET;
                ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS;
        }

        ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
        ndev->limits.msix_cnt = SNB_MSIX_CNT;
        ndev->bits_per_vector = SNB_DB_BITS_PER_VEC;

        return 0;
}

static int ntb_bwd_setup(struct ntb_device *ndev)
{
        int rc;
        u32 val;

        ndev->hw_type = BWD_HW;

        rc = pci_read_config_dword(ndev->pdev, NTB_PPD_OFFSET, &val);
        if (rc)
                return rc;

        switch ((val & BWD_PPD_CONN_TYPE) >> 8) {
        case NTB_CONN_B2B:
                ndev->conn_type = NTB_CONN_B2B;
                break;
        case NTB_CONN_RP:
        default:
                dev_err(&ndev->pdev->dev, "Only B2B supported at this time\n");
                return -EINVAL;
        }

        if (val & BWD_PPD_DEV_TYPE)
                ndev->dev_type = NTB_DEV_DSD;
        else
                ndev->dev_type = NTB_DEV_USD;

        /* Initiate PCI-E link training */
        rc = pci_write_config_dword(ndev->pdev, NTB_PPD_OFFSET,
                                    val | BWD_PPD_INIT_LINK);
        if (rc)
                return rc;

        ndev->reg_ofs.pdb = ndev->reg_base + BWD_PDOORBELL_OFFSET;
        ndev->reg_ofs.pdb_mask = ndev->reg_base + BWD_PDBMSK_OFFSET;
        ndev->reg_ofs.sbar2_xlat = ndev->reg_base + BWD_SBAR2XLAT_OFFSET;
        ndev->reg_ofs.sbar4_xlat = ndev->reg_base + BWD_SBAR4XLAT_OFFSET;
        ndev->reg_ofs.lnk_cntl = ndev->reg_base + BWD_NTBCNTL_OFFSET;
        ndev->reg_ofs.lnk_stat = ndev->reg_base + BWD_LINK_STATUS_OFFSET;
        ndev->reg_ofs.spad_read = ndev->reg_base + BWD_SPAD_OFFSET;
        ndev->reg_ofs.spci_cmd = ndev->reg_base + BWD_PCICMD_OFFSET;

        if (ndev->conn_type == NTB_CONN_B2B) {
                ndev->reg_ofs.sdb = ndev->reg_base + BWD_B2B_DOORBELL_OFFSET;
                ndev->reg_ofs.spad_write = ndev->reg_base + BWD_B2B_SPAD_OFFSET;
                ndev->limits.max_spads = BWD_MAX_SPADS;
        } else {
                ndev->reg_ofs.sdb = ndev->reg_base + BWD_PDOORBELL_OFFSET;
                ndev->reg_ofs.spad_write = ndev->reg_base + BWD_SPAD_OFFSET;
                ndev->limits.max_spads = BWD_MAX_COMPAT_SPADS;
        }

        ndev->limits.max_db_bits = BWD_MAX_DB_BITS;
        ndev->limits.msix_cnt = BWD_MSIX_CNT;
        ndev->bits_per_vector = BWD_DB_BITS_PER_VEC;

        /* Since bwd doesn't have a link interrupt, setup a poll timer */
        INIT_DELAYED_WORK(&ndev->hb_timer, bwd_link_poll);
        schedule_delayed_work(&ndev->hb_timer, NTB_HB_TIMEOUT);

        return 0;
}

static int ntb_device_setup(struct ntb_device *ndev)
{
        int rc;

        switch (ndev->pdev->device) {
        case PCI_DEVICE_ID_INTEL_NTB_2ND_SNB:
        case PCI_DEVICE_ID_INTEL_NTB_RP_JSF:
        case PCI_DEVICE_ID_INTEL_NTB_RP_SNB:
        case PCI_DEVICE_ID_INTEL_NTB_CLASSIC_JSF:
        case PCI_DEVICE_ID_INTEL_NTB_CLASSIC_SNB:
        case PCI_DEVICE_ID_INTEL_NTB_B2B_JSF:
        case PCI_DEVICE_ID_INTEL_NTB_B2B_SNB:
                rc = ntb_xeon_setup(ndev);
                break;
        case PCI_DEVICE_ID_INTEL_NTB_B2B_BWD:
                rc = ntb_bwd_setup(ndev);
                break;
        default:
                rc = -ENODEV;
        }

        /* Enable Bus Master and Memory Space on the secondary side */
        writew(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER, ndev->reg_ofs.spci_cmd);

        return rc;
}

static void ntb_device_free(struct ntb_device *ndev)
{
        if (ndev->hw_type == BWD_HW)
                cancel_delayed_work_sync(&ndev->hb_timer);
}

static irqreturn_t bwd_callback_msix_irq(int irq, void *data)
{
        struct ntb_db_cb *db_cb = data;
        struct ntb_device *ndev = db_cb->ndev;

        dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
                db_cb->db_num);

        if (db_cb->callback)
                db_cb->callback(db_cb->data, db_cb->db_num);

        /* No need to check for the specific HB irq, any interrupt means
         * we're connected.
         */
        ndev->last_ts = jiffies;

        writeq((u64) 1 << db_cb->db_num, ndev->reg_ofs.pdb);

        return IRQ_HANDLED;
}

static irqreturn_t xeon_callback_msix_irq(int irq, void *data)
{
        struct ntb_db_cb *db_cb = data;
        struct ntb_device *ndev = db_cb->ndev;

        dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
                db_cb->db_num);

        if (db_cb->callback)
                db_cb->callback(db_cb->data, db_cb->db_num);

        /* On Sandybridge, there are 16 bits in the interrupt register
         * but only 4 vectors.  So, 5 bits are assigned to the first 3
         * vectors, with the 4th having a single bit for link
         * interrupts.
         */
        writew(((1 << ndev->bits_per_vector) - 1) <<
               (db_cb->db_num * ndev->bits_per_vector), ndev->reg_ofs.pdb);

        return IRQ_HANDLED;
}

/* Since we do not have a HW doorbell in BWD, this is only used in JF/JT */
static irqreturn_t xeon_event_msix_irq(int irq, void *dev)
{
        struct ntb_device *ndev = dev;
        int rc;

        dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for Events\n", irq);

        rc = ntb_link_status(ndev);
        if (rc)
                dev_err(&ndev->pdev->dev, "Error determining link status\n");

        /* bit 15 is always the link bit */
        writew(1 << ndev->limits.max_db_bits, ndev->reg_ofs.pdb);

        return IRQ_HANDLED;
}

static irqreturn_t ntb_interrupt(int irq, void *dev)
{
        struct ntb_device *ndev = dev;
        unsigned int i = 0;

        if (ndev->hw_type == BWD_HW) {
                u64 pdb = readq(ndev->reg_ofs.pdb);

                dev_dbg(&ndev->pdev->dev, "irq %d - pdb = %Lx\n", irq, pdb);

                while (pdb) {
                        i = __ffs(pdb);
                        pdb &= pdb - 1;
                        bwd_callback_msix_irq(irq, &ndev->db_cb[i]);
                }
        } else {
                u16 pdb = readw(ndev->reg_ofs.pdb);

                dev_dbg(&ndev->pdev->dev, "irq %d - pdb = %x sdb %x\n", irq,
                        pdb, readw(ndev->reg_ofs.sdb));

                if (pdb & SNB_DB_HW_LINK) {
                        xeon_event_msix_irq(irq, dev);
                        pdb &= ~SNB_DB_HW_LINK;
                }

                while (pdb) {
                        i = __ffs(pdb);
                        pdb &= pdb - 1;
                        xeon_callback_msix_irq(irq, &ndev->db_cb[i]);
                }
        }

        return IRQ_HANDLED;
}

static int ntb_setup_msix(struct ntb_device *ndev)
{
        struct pci_dev *pdev = ndev->pdev;
        struct msix_entry *msix;
        int msix_entries;
        int rc, i, pos;
        u16 val;

        pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
        if (!pos) {
                rc = -EIO;
                goto err;
        }

        rc = pci_read_config_word(pdev, pos + PCI_MSIX_FLAGS, &val);
        if (rc)
                goto err;

        msix_entries = msix_table_size(val);
        if (msix_entries > ndev->limits.msix_cnt) {
                rc = -EINVAL;
                goto err;
        }

        ndev->msix_entries = kmalloc(sizeof(struct msix_entry) * msix_entries,
                                     GFP_KERNEL);
        if (!ndev->msix_entries) {
                rc = -ENOMEM;
                goto err;
        }

        for (i = 0; i < msix_entries; i++)
                ndev->msix_entries[i].entry = i;

        rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
        if (rc < 0)
                goto err1;
        if (rc > 0) {
                /* On SNB, the link interrupt is always tied to 4th vector.  If
                 * we can't get all 4, then we can't use MSI-X.
                 */
                if (ndev->hw_type != BWD_HW) {
                        rc = -EIO;
                        goto err1;
                }

                dev_warn(&pdev->dev,
                         "Only %d MSI-X vectors.  Limiting the number of queues to that number.\n",
                         rc);
                msix_entries = rc;
        }

        for (i = 0; i < msix_entries; i++) {
                msix = &ndev->msix_entries[i];
                WARN_ON(!msix->vector);

                /* Use the last MSI-X vector for Link status */
                if (ndev->hw_type == BWD_HW) {
                        rc = request_irq(msix->vector, bwd_callback_msix_irq, 0,
                                         "ntb-callback-msix", &ndev->db_cb[i]);
                        if (rc)
                                goto err2;
                } else {
                        if (i == msix_entries - 1) {
                                rc = request_irq(msix->vector,
                                                 xeon_event_msix_irq, 0,
                                                 "ntb-event-msix", ndev);
                                if (rc)
                                        goto err2;
                        } else {
                                rc = request_irq(msix->vector,
                                                 xeon_callback_msix_irq, 0,
                                                 "ntb-callback-msix",
                                                 &ndev->db_cb[i]);
                                if (rc)
                                        goto err2;
                        }
                }
        }

        ndev->num_msix = msix_entries;
        if (ndev->hw_type == BWD_HW)
                ndev->max_cbs = msix_entries;
        else
                ndev->max_cbs = msix_entries - 1;

        return 0;

err2:
        while (--i >= 0) {
                msix = &ndev->msix_entries[i];
                if (ndev->hw_type != BWD_HW && i == ndev->num_msix - 1)
                        free_irq(msix->vector, ndev);
                else
                        free_irq(msix->vector, &ndev->db_cb[i]);
        }
        pci_disable_msix(pdev);
err1:
        kfree(ndev->msix_entries);
        dev_err(&pdev->dev, "Error allocating MSI-X interrupt\n");
err:
        ndev->num_msix = 0;
        return rc;
}

static int ntb_setup_msi(struct ntb_device *ndev)
{
        struct pci_dev *pdev = ndev->pdev;
        int rc;

        rc = pci_enable_msi(pdev);
        if (rc)
                return rc;

        rc = request_irq(pdev->irq, ntb_interrupt, 0, "ntb-msi", ndev);
        if (rc) {
                pci_disable_msi(pdev);
                dev_err(&pdev->dev, "Error allocating MSI interrupt\n");
                return rc;
        }

        return 0;
}

static int ntb_setup_intx(struct ntb_device *ndev)
{
        struct pci_dev *pdev = ndev->pdev;
        int rc;

        pci_msi_off(pdev);

        /* Verify intx is enabled */
        pci_intx(pdev, 1);

        rc = request_irq(pdev->irq, ntb_interrupt, IRQF_SHARED, "ntb-intx",
                         ndev);
        if (rc)
                return rc;

        return 0;
}

static int ntb_setup_interrupts(struct ntb_device *ndev)
{
        int rc;

        /* On BWD, disable all interrupts.  On SNB, disable all but Link
         * Interrupt.  The rest will be unmasked as callbacks are registered.
         */
        if (ndev->hw_type == BWD_HW)
                writeq(~0, ndev->reg_ofs.pdb_mask);
        else
                writew(~(1 << ndev->limits.max_db_bits),
                       ndev->reg_ofs.pdb_mask);

        rc = ntb_setup_msix(ndev);
        if (!rc)
                goto done;

        ndev->bits_per_vector = 1;
        ndev->max_cbs = ndev->limits.max_db_bits;

        rc = ntb_setup_msi(ndev);
        if (!rc)
                goto done;

        rc = ntb_setup_intx(ndev);
        if (rc) {
                dev_err(&ndev->pdev->dev, "no usable interrupts\n");
                return rc;
        }

done:
        return 0;
}

static void ntb_free_interrupts(struct ntb_device *ndev)
{
        struct pci_dev *pdev = ndev->pdev;

        /* mask interrupts */
        if (ndev->hw_type == BWD_HW)
                writeq(~0, ndev->reg_ofs.pdb_mask);
        else
                writew(~0, ndev->reg_ofs.pdb_mask);

        if (ndev->num_msix) {
                struct msix_entry *msix;
                u32 i;

                for (i = 0; i < ndev->num_msix; i++) {
                        msix = &ndev->msix_entries[i];
                        if (ndev->hw_type != BWD_HW && i == ndev->num_msix - 1)
                                free_irq(msix->vector, ndev);
                        else
                                free_irq(msix->vector, &ndev->db_cb[i]);
                }
                pci_disable_msix(pdev);
        } else {
                free_irq(pdev->irq, ndev);

                if (pci_dev_msi_enabled(pdev))
                        pci_disable_msi(pdev);
        }
}

static int ntb_create_callbacks(struct ntb_device *ndev)
{
        int i;

        /* Checken-egg issue.  We won't know how many callbacks are necessary
         * until we see how many MSI-X vectors we get, but these pointers need
         * to be passed into the MSI-X register fucntion.  So, we allocate the
         * max, knowing that they might not all be used, to work around this.
         */
        ndev->db_cb = kcalloc(ndev->limits.max_db_bits,
                              sizeof(struct ntb_db_cb),
                              GFP_KERNEL);
        if (!ndev->db_cb)
                return -ENOMEM;

        for (i = 0; i < ndev->limits.max_db_bits; i++) {
                ndev->db_cb[i].db_num = i;
                ndev->db_cb[i].ndev = ndev;
        }

        return 0;
}

static void ntb_free_callbacks(struct ntb_device *ndev)
{
        int i;

        for (i = 0; i < ndev->limits.max_db_bits; i++)
                ntb_unregister_db_callback(ndev, i);

        kfree(ndev->db_cb);
}

static int ntb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct ntb_device *ndev;
        int rc, i;

        ndev = kzalloc(sizeof(struct ntb_device), GFP_KERNEL);

        if (!ndev)
                return -ENOMEM;

        ndev->pdev = pdev;
        ndev->link_status = NTB_LINK_DOWN;
        pci_set_drvdata(pdev, ndev);

        rc = pci_enable_device(pdev);
        if (rc)
                goto err;

        pci_set_master(ndev->pdev);

        rc = pci_request_selected_regions(pdev, NTB_BAR_MASK, KBUILD_MODNAME);
        if (rc)
                goto err1;

        ndev->reg_base = pci_ioremap_bar(pdev, NTB_BAR_MMIO);
        if (!ndev->reg_base) {
                dev_warn(&pdev->dev, "Cannot remap BAR 0\n");
                rc = -EIO;
                goto err2;
        }

        for (i = 0; i < NTB_NUM_MW; i++) {
                ndev->mw[i].bar_sz = pci_resource_len(pdev, MW_TO_BAR(i));
                ndev->mw[i].vbase =
                    ioremap_wc(pci_resource_start(pdev, MW_TO_BAR(i)),
                               ndev->mw[i].bar_sz);
                dev_info(&pdev->dev, "MW %d size %llu\n", i,
                         pci_resource_len(pdev, MW_TO_BAR(i)));
                if (!ndev->mw[i].vbase) {
                        dev_warn(&pdev->dev, "Cannot remap BAR %d\n",
                                 MW_TO_BAR(i));
                        rc = -EIO;
                        goto err3;
                }
        }

        rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
        if (rc) {
                rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
                if (rc)
                        goto err3;

                dev_warn(&pdev->dev, "Cannot DMA highmem\n");
        }

        rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
        if (rc) {
                rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
                if (rc)
                        goto err3;

                dev_warn(&pdev->dev, "Cannot DMA consistent highmem\n");
        }

        rc = ntb_device_setup(ndev);
        if (rc)
                goto err3;

        rc = ntb_create_callbacks(ndev);
        if (rc)
                goto err4;

        rc = ntb_setup_interrupts(ndev);
        if (rc)
                goto err5;

        /* The scratchpad registers keep the values between rmmod/insmod,
         * blast them now
         */
        for (i = 0; i < ndev->limits.max_spads; i++) {
                ntb_write_local_spad(ndev, i, 0);
                ntb_write_remote_spad(ndev, i, 0);
        }

        rc = ntb_transport_init(pdev);
        if (rc)
                goto err6;

        /* Let's bring the NTB link up */
        writel(NTB_CNTL_BAR23_SNOOP | NTB_CNTL_BAR45_SNOOP,
               ndev->reg_ofs.lnk_cntl);

        return 0;

err6:
        ntb_free_interrupts(ndev);
err5:
        ntb_free_callbacks(ndev);
err4:
        ntb_device_free(ndev);
err3:
        for (i--; i >= 0; i--)
                iounmap(ndev->mw[i].vbase);
        iounmap(ndev->reg_base);
err2:
        pci_release_selected_regions(pdev, NTB_BAR_MASK);
err1:
        pci_disable_device(pdev);
err:
        kfree(ndev);

        dev_err(&pdev->dev, "Error loading %s module\n", KBUILD_MODNAME);
        return rc;
}

static void ntb_pci_remove(struct pci_dev *pdev)
{
        struct ntb_device *ndev = pci_get_drvdata(pdev);
        int i;
        u32 ntb_cntl;

        /* Bring NTB link down */
        ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
        ntb_cntl |= NTB_LINK_DISABLE;
        writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);

        ntb_transport_free(ndev->ntb_transport);

        ntb_free_interrupts(ndev);
        ntb_free_callbacks(ndev);
        ntb_device_free(ndev);

        for (i = 0; i < NTB_NUM_MW; i++)
                iounmap(ndev->mw[i].vbase);

        iounmap(ndev->reg_base);
        pci_release_selected_regions(pdev, NTB_BAR_MASK);
        pci_disable_device(pdev);
        kfree(ndev);
}

static struct pci_driver ntb_pci_driver = {
        .name = KBUILD_MODNAME,
        .id_table = ntb_pci_tbl,
        .probe = ntb_pci_probe,
        .remove = ntb_pci_remove,
};
module_pci_driver(ntb_pci_driver);