/*
 * Copyright (c) 2006, 2007 Cisco Systems, Inc.  All rights reserved.
 * Copyright (c) 2007, 2008 Mellanox Technologies. 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 <linux/jiffies.h>

#include "mlx4.h"

int mlx4_reset(struct mlx4_dev *dev)
{
        void __iomem *reset;
        u32 *hca_header = NULL;
        int pcie_cap;
        u16 devctl;
        u16 linkctl;
        u16 vendor;
        unsigned long end;
        u32 sem;
        int i;
        int err = 0;

#define MLX4_RESET_BASE         0xf0000
#define MLX4_RESET_SIZE           0x400
#define MLX4_SEM_OFFSET           0x3fc
#define MLX4_RESET_OFFSET          0x10
#define MLX4_RESET_VALUE        swab32(1)

#define MLX4_SEM_TIMEOUT_JIFFIES        (10 * HZ)
#define MLX4_RESET_TIMEOUT_JIFFIES      (2 * HZ)

        /*
         * 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.
         */

        /* Do we need to save off the full 4K PCI Express header?? */
        hca_header = kmalloc(256, GFP_KERNEL);
        if (!hca_header) {
                err = -ENOMEM;
                mlx4_err(dev, "Couldn't allocate memory to save HCA PCI header, aborting\n");
                goto out;
        }

        pcie_cap = pci_pcie_cap(dev->persist->pdev);

        for (i = 0; i < 64; ++i) {
                if (i == 22 || i == 23)
                        continue;
                if (pci_read_config_dword(dev->persist->pdev, i * 4,
                                          hca_header + i)) {
                        err = -ENODEV;
                        mlx4_err(dev, "Couldn't save HCA PCI header, aborting\n");
                        goto out;
                }
        }

        reset = ioremap(pci_resource_start(dev->persist->pdev, 0) +
                        MLX4_RESET_BASE,
                        MLX4_RESET_SIZE);
        if (!reset) {
                err = -ENOMEM;
                mlx4_err(dev, "Couldn't map HCA reset register, aborting\n");
                goto out;
        }

        /* grab HW semaphore to lock out flash updates */
        end = jiffies + MLX4_SEM_TIMEOUT_JIFFIES;
        do {
                sem = readl(reset + MLX4_SEM_OFFSET);
                if (!sem)
                        break;

                msleep(1);
        } while (time_before(jiffies, end));

        if (sem) {
                mlx4_err(dev, "Failed to obtain HW semaphore, aborting\n");
                err = -EAGAIN;
                iounmap(reset);
                goto out;
        }

        /* actually hit reset */
        writel(MLX4_RESET_VALUE, reset + MLX4_RESET_OFFSET);
        iounmap(reset);

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

        end = jiffies + MLX4_RESET_TIMEOUT_JIFFIES;
        do {
                if (!pci_read_config_word(dev->persist->pdev, PCI_VENDOR_ID,
                                          &vendor) && vendor != 0xffff)
                        break;

                msleep(1);
        } while (time_before(jiffies, end));

        if (vendor == 0xffff) {
                err = -ENODEV;
                mlx4_err(dev, "PCI device did not come back after reset, aborting\n");
                goto out;
        }

        /* Now restore the PCI headers */
        if (pcie_cap) {
                devctl = hca_header[(pcie_cap + PCI_EXP_DEVCTL) / 4];
                if (pcie_capability_write_word(dev->persist->pdev,
                                               PCI_EXP_DEVCTL,
                                               devctl)) {
                        err = -ENODEV;
                        mlx4_err(dev, "Couldn't restore HCA PCI Express Device Control register, aborting\n");
                        goto out;
                }
                linkctl = hca_header[(pcie_cap + PCI_EXP_LNKCTL) / 4];
                if (pcie_capability_write_word(dev->persist->pdev,
                                               PCI_EXP_LNKCTL,
                                               linkctl)) {
                        err = -ENODEV;
                        mlx4_err(dev, "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(dev->persist->pdev, i * 4,
                                           hca_header[i])) {
                        err = -ENODEV;
                        mlx4_err(dev, "Couldn't restore HCA reg %x, aborting\n",
                                 i);
                        goto out;
                }
        }

        if (pci_write_config_dword(dev->persist->pdev, PCI_COMMAND,
                                   hca_header[PCI_COMMAND / 4])) {
                err = -ENODEV;
                mlx4_err(dev, "Couldn't restore HCA COMMAND, aborting\n");
                goto out;
        }

out:
        kfree(hca_header);

        return err;
}