/*
 * Copyright (c) 2004 Topspin Communications.  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/errno.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/slab.h>

#include "mthca_dev.h"
#include "mthca_cmd.h"

int mthca_reset(struct mthca_dev *mdev)
{
        int i;
        int err = 0;
        u32 *hca_header    = NULL;
#ifdef __linux__
        u32 *bridge_header = NULL;
#endif
        struct pci_dev *bridge = NULL;
#ifdef __linux__
        int bridge_pcix_cap = 0;
#endif
        int hca_pcie_cap = 0;
        int hca_pcix_cap = 0;

        u16 devctl;
        u16 linkctl;

#define MTHCA_RESET_OFFSET 0xf0010
#define MTHCA_RESET_VALUE  swab32(1)

        /*
         * Reset the chip.  This is somewhat ugly because we have to
         * save off the PCI header before reset and then restore it
         * after the chip reboots.  We skip config space offsets 22
         * and 23 since those have a special meaning.
         *
         * To make matters worse, for Tavor (PCI-X HCA) we have to
         * find the associated bridge device and save off its PCI
         * header as well.
         */

        if (!(mdev->mthca_flags & MTHCA_FLAG_PCIE)) {
                /* Look for the bridge -- its device ID will be 2 more
                   than HCA's device ID. */
#ifdef __linux__
                while ((bridge = pci_get_device(mdev->pdev->vendor,
                                                mdev->pdev->device + 2,
                                                bridge)) != NULL) {
                        if (bridge->hdr_type    == PCI_HEADER_TYPE_BRIDGE &&
                            bridge->subordinate == mdev->pdev->bus) {
                                mthca_dbg(mdev, "Found bridge: %s\n",
                                          pci_name(bridge));
                                break;
                        }
                }

                if (!bridge) {
                        /*
                         * Didn't find a bridge for a Tavor device --
                         * assume we're in no-bridge mode and hope for
                         * the best.
                         */
                        mthca_warn(mdev, "No bridge found for %s\n",
                                  pci_name(mdev->pdev));
                }
#else
                mthca_warn(mdev, "Reset on PCI-X is not supported.\n");
                goto out;

#endif
        }

        /* For Arbel do we need to save off the full 4K PCI Express header?? */
        hca_header = kmalloc(256, GFP_KERNEL);
        if (!hca_header) {
                err = -ENOMEM;
                mthca_err(mdev, "Couldn't allocate memory to save HCA "
                          "PCI header, aborting.\n");
                goto out;
        }

        for (i = 0; i < 64; ++i) {
                if (i == 22 || i == 23)
                        continue;
                if (pci_read_config_dword(mdev->pdev, i * 4, hca_header + i)) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't save HCA "
                                  "PCI header, aborting.\n");
                        goto out;
                }
        }

        hca_pcix_cap = pci_find_capability(mdev->pdev, PCI_CAP_ID_PCIX);
        hca_pcie_cap = pci_find_capability(mdev->pdev, PCI_CAP_ID_EXP);

#ifdef __linux__
        if (bridge) {
                bridge_header = kmalloc(256, GFP_KERNEL);
                if (!bridge_header) {
                        err = -ENOMEM;
                        mthca_err(mdev, "Couldn't allocate memory to save HCA "
                                  "bridge PCI header, aborting.\n");
                        goto out;
                }

                for (i = 0; i < 64; ++i) {
                        if (i == 22 || i == 23)
                                continue;
                        if (pci_read_config_dword(bridge, i * 4, bridge_header + i)) {
                                err = -ENODEV;
                                mthca_err(mdev, "Couldn't save HCA bridge "
                                          "PCI header, aborting.\n");
                                goto out;
                        }
                }
                bridge_pcix_cap = pci_find_capability(bridge, PCI_CAP_ID_PCIX);
                if (!bridge_pcix_cap) {
                                err = -ENODEV;
                                mthca_err(mdev, "Couldn't locate HCA bridge "
                                          "PCI-X capability, aborting.\n");
                                goto out;
                }
        }
#endif

        /* actually hit reset */
        {
                void __iomem *reset = ioremap(pci_resource_start(mdev->pdev, 0) +
                                              MTHCA_RESET_OFFSET, 4);

                if (!reset) {
                        err = -ENOMEM;
                        mthca_err(mdev, "Couldn't map HCA reset register, "
                                  "aborting.\n");
                        goto out;
                }

                writel(MTHCA_RESET_VALUE, reset);
                iounmap(reset);
        }

        /* Docs say to wait one second before accessing device */
        msleep(1000);

        /* Now wait for PCI device to start responding again */
        {
                u32 v;
                int c = 0;

                for (c = 0; c < 100; ++c) {
                        if (pci_read_config_dword(bridge ? bridge : mdev->pdev, 0, &v)) {
                                err = -ENODEV;
                                mthca_err(mdev, "Couldn't access HCA after reset, "
                                          "aborting.\n");
                                goto out;
                        }

                        if (v != 0xffffffff)
                                goto good;

                        msleep(100);
                }

                err = -ENODEV;
                mthca_err(mdev, "PCI device did not come back after reset, "
                          "aborting.\n");
                goto out;
        }

good:
#ifdef __linux__
        /* Now restore the PCI headers */
        if (bridge) {
                if (pci_write_config_dword(bridge, bridge_pcix_cap + 0x8,
                                 bridge_header[(bridge_pcix_cap + 0x8) / 4])) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't restore HCA bridge Upstream "
                                  "split transaction control, aborting.\n");
                        goto out;
                }
                if (pci_write_config_dword(bridge, bridge_pcix_cap + 0xc,
                                 bridge_header[(bridge_pcix_cap + 0xc) / 4])) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't restore HCA bridge Downstream "
                                  "split transaction control, aborting.\n");
                        goto out;
                }
                /*
                 * Bridge control register is at 0x3e, so we'll
                 * naturally restore it last in this loop.
                 */
                for (i = 0; i < 16; ++i) {
                        if (i * 4 == PCI_COMMAND)
                                continue;

                        if (pci_write_config_dword(bridge, i * 4, bridge_header[i])) {
                                err = -ENODEV;
                                mthca_err(mdev, "Couldn't restore HCA bridge reg %x, "
                                          "aborting.\n", i);
                                goto out;
                        }
                }

                if (pci_write_config_dword(bridge, PCI_COMMAND,
                                           bridge_header[PCI_COMMAND / 4])) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't restore HCA bridge COMMAND, "
                                  "aborting.\n");
                        goto out;
                }
        }
#endif

        if (hca_pcix_cap) {
                if (pci_write_config_dword(mdev->pdev, hca_pcix_cap,
                                 hca_header[hca_pcix_cap / 4])) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't restore HCA PCI-X "
                                  "command register, aborting.\n");
                        goto out;
                }
        }

        if (hca_pcie_cap) {
                devctl = hca_header[(hca_pcie_cap + PCI_EXP_DEVCTL) / 4];
                if (pci_write_config_word(mdev->pdev, hca_pcie_cap + PCI_EXP_DEVCTL,
                                           devctl)) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't restore HCA PCI Express "
                                  "Device Control register, aborting.\n");
                        goto out;
                }
                linkctl = hca_header[(hca_pcie_cap + PCI_EXP_LNKCTL) / 4];
                if (pci_write_config_word(mdev->pdev, hca_pcie_cap + PCI_EXP_LNKCTL,
                                           linkctl)) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't restore HCA PCI Express "
                                  "Link control register, aborting.\n");
                        goto out;
                }
        }

        for (i = 0; i < 16; ++i) {
                if (i * 4 == PCI_COMMAND)
                        continue;

                if (pci_write_config_dword(mdev->pdev, i * 4, hca_header[i])) {
                        err = -ENODEV;
                        mthca_err(mdev, "Couldn't restore HCA reg %x, "
                                  "aborting.\n", i);
                        goto out;
                }
        }

        if (pci_write_config_dword(mdev->pdev, PCI_COMMAND,
                                   hca_header[PCI_COMMAND / 4])) {
                err = -ENODEV;
                mthca_err(mdev, "Couldn't restore HCA COMMAND, "
                          "aborting.\n");
                goto out;
        }

out:
#ifdef __linux__
        if (bridge)
                pci_dev_put(bridge);
        kfree(bridge_header);
#endif
        kfree(hca_header);

        return err;
}