// SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0-only)
/* Copyright(c) 2014 - 2020 Intel Corporation */
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/aer.h>
#include <linux/completion.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include "adf_accel_devices.h"
#include "adf_common_drv.h"

static struct workqueue_struct *device_reset_wq;

static pci_ers_result_t adf_error_detected(struct pci_dev *pdev,
                                           pci_channel_state_t state)
{
        struct adf_accel_dev *accel_dev = adf_devmgr_pci_to_accel_dev(pdev);

        dev_info(&pdev->dev, "Acceleration driver hardware error detected.\n");
        if (!accel_dev) {
                dev_err(&pdev->dev, "Can't find acceleration device\n");
                return PCI_ERS_RESULT_DISCONNECT;
        }

        if (state == pci_channel_io_perm_failure) {
                dev_err(&pdev->dev, "Can't recover from device error\n");
                return PCI_ERS_RESULT_DISCONNECT;
        }

        return PCI_ERS_RESULT_NEED_RESET;
}

/* reset dev data */
struct adf_reset_dev_data {
        int mode;
        struct adf_accel_dev *accel_dev;
        struct completion compl;
        struct work_struct reset_work;
};

void adf_reset_sbr(struct adf_accel_dev *accel_dev)
{
        struct pci_dev *pdev = accel_to_pci_dev(accel_dev);
        struct pci_dev *parent = pdev->bus->self;
        u16 bridge_ctl = 0;

        if (!parent)
                parent = pdev;

        if (!pci_wait_for_pending_transaction(pdev))
                dev_info(&GET_DEV(accel_dev),
                         "Transaction still in progress. Proceeding\n");

        dev_info(&GET_DEV(accel_dev), "Secondary bus reset\n");

        pci_read_config_word(parent, PCI_BRIDGE_CONTROL, &bridge_ctl);
        bridge_ctl |= PCI_BRIDGE_CTL_BUS_RESET;
        pci_write_config_word(parent, PCI_BRIDGE_CONTROL, bridge_ctl);
        msleep(100);
        bridge_ctl &= ~PCI_BRIDGE_CTL_BUS_RESET;
        pci_write_config_word(parent, PCI_BRIDGE_CONTROL, bridge_ctl);
        msleep(100);
}
EXPORT_SYMBOL_GPL(adf_reset_sbr);

void adf_reset_flr(struct adf_accel_dev *accel_dev)
{
        pcie_flr(accel_to_pci_dev(accel_dev));
}
EXPORT_SYMBOL_GPL(adf_reset_flr);

void adf_dev_restore(struct adf_accel_dev *accel_dev)
{
        struct adf_hw_device_data *hw_device = accel_dev->hw_device;
        struct pci_dev *pdev = accel_to_pci_dev(accel_dev);

        if (hw_device->reset_device) {
                dev_info(&GET_DEV(accel_dev), "Resetting device qat_dev%d\n",
                         accel_dev->accel_id);
                hw_device->reset_device(accel_dev);
                pci_restore_state(pdev);
                pci_save_state(pdev);
        }
}

static void adf_device_reset_worker(struct work_struct *work)
{
        struct adf_reset_dev_data *reset_data =
                  container_of(work, struct adf_reset_dev_data, reset_work);
        struct adf_accel_dev *accel_dev = reset_data->accel_dev;

        adf_dev_restarting_notify(accel_dev);
        adf_dev_stop(accel_dev);
        adf_dev_shutdown(accel_dev);
        if (adf_dev_init(accel_dev) || adf_dev_start(accel_dev)) {
                /* The device hanged and we can't restart it so stop here */
                dev_err(&GET_DEV(accel_dev), "Restart device failed\n");
                kfree(reset_data);
                WARN(1, "QAT: device restart failed. Device is unusable\n");
                return;
        }
        adf_dev_restarted_notify(accel_dev);
        clear_bit(ADF_STATUS_RESTARTING, &accel_dev->status);

        /* The dev is back alive. Notify the caller if in sync mode */
        if (reset_data->mode == ADF_DEV_RESET_SYNC)
                complete(&reset_data->compl);
        else
                kfree(reset_data);
}

static int adf_dev_aer_schedule_reset(struct adf_accel_dev *accel_dev,
                                      enum adf_dev_reset_mode mode)
{
        struct adf_reset_dev_data *reset_data;

        if (!adf_dev_started(accel_dev) ||
            test_bit(ADF_STATUS_RESTARTING, &accel_dev->status))
                return 0;

        set_bit(ADF_STATUS_RESTARTING, &accel_dev->status);
        reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
        if (!reset_data)
                return -ENOMEM;
        reset_data->accel_dev = accel_dev;
        init_completion(&reset_data->compl);
        reset_data->mode = mode;
        INIT_WORK(&reset_data->reset_work, adf_device_reset_worker);
        queue_work(device_reset_wq, &reset_data->reset_work);

        /* If in sync mode wait for the result */
        if (mode == ADF_DEV_RESET_SYNC) {
                int ret = 0;
                /* Maximum device reset time is 10 seconds */
                unsigned long wait_jiffies = msecs_to_jiffies(10000);
                unsigned long timeout = wait_for_completion_timeout(
                                   &reset_data->compl, wait_jiffies);
                if (!timeout) {
                        dev_err(&GET_DEV(accel_dev),
                                "Reset device timeout expired\n");
                        ret = -EFAULT;
                }
                kfree(reset_data);
                return ret;
        }
        return 0;
}

static pci_ers_result_t adf_slot_reset(struct pci_dev *pdev)
{
        struct adf_accel_dev *accel_dev = adf_devmgr_pci_to_accel_dev(pdev);

        if (!accel_dev) {
                pr_err("QAT: Can't find acceleration device\n");
                return PCI_ERS_RESULT_DISCONNECT;
        }
        if (adf_dev_aer_schedule_reset(accel_dev, ADF_DEV_RESET_SYNC))
                return PCI_ERS_RESULT_DISCONNECT;

        return PCI_ERS_RESULT_RECOVERED;
}

static void adf_resume(struct pci_dev *pdev)
{
        dev_info(&pdev->dev, "Acceleration driver reset completed\n");
        dev_info(&pdev->dev, "Device is up and running\n");
}

static const struct pci_error_handlers adf_err_handler = {
        .error_detected = adf_error_detected,
        .slot_reset = adf_slot_reset,
        .resume = adf_resume,
};

/**
 * adf_enable_aer() - Enable Advance Error Reporting for acceleration device
 * @accel_dev:  Pointer to acceleration device.
 *
 * Function enables PCI Advance Error Reporting for the
 * QAT acceleration device accel_dev.
 * To be used by QAT device specific drivers.
 *
 * Return: 0 on success, error code otherwise.
 */
int adf_enable_aer(struct adf_accel_dev *accel_dev)
{
        struct pci_dev *pdev = accel_to_pci_dev(accel_dev);
        struct pci_driver *pdrv = pdev->driver;

        pdrv->err_handler = &adf_err_handler;
        pci_enable_pcie_error_reporting(pdev);
        return 0;
}
EXPORT_SYMBOL_GPL(adf_enable_aer);

/**
 * adf_disable_aer() - Disable Advance Error Reporting for acceleration device
 * @accel_dev:  Pointer to acceleration device.
 *
 * Function disables PCI Advance Error Reporting for the
 * QAT acceleration device accel_dev.
 * To be used by QAT device specific drivers.
 *
 * Return: void
 */
void adf_disable_aer(struct adf_accel_dev *accel_dev)
{
        struct pci_dev *pdev = accel_to_pci_dev(accel_dev);

        pci_disable_pcie_error_reporting(pdev);
}
EXPORT_SYMBOL_GPL(adf_disable_aer);

int adf_init_aer(void)
{
        device_reset_wq = alloc_workqueue("qat_device_reset_wq",
                                          WQ_MEM_RECLAIM, 0);
        return !device_reset_wq ? -EFAULT : 0;
}

void adf_exit_aer(void)
{
        if (device_reset_wq)
                destroy_workqueue(device_reset_wq);
        device_reset_wq = NULL;
}