// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright 2016-2019 HabanaLabs, Ltd.
 * All Rights Reserved.
 *
 */

#define pr_fmt(fmt)             "habanalabs: " fmt

#include "habanalabs.h"

#include <linux/pci.h>
#include <linux/module.h>

#define HL_DRIVER_AUTHOR        "HabanaLabs Kernel Driver Team"

#define HL_DRIVER_DESC          "Driver for HabanaLabs's AI Accelerators"

MODULE_AUTHOR(HL_DRIVER_AUTHOR);
MODULE_DESCRIPTION(HL_DRIVER_DESC);
MODULE_LICENSE("GPL v2");

static int hl_major;
static struct class *hl_class;
static DEFINE_IDR(hl_devs_idr);
static DEFINE_MUTEX(hl_devs_idr_lock);

static int timeout_locked = 5;
static int reset_on_lockup = 1;

module_param(timeout_locked, int, 0444);
MODULE_PARM_DESC(timeout_locked,
        "Device lockup timeout in seconds (0 = disabled, default 5s)");

module_param(reset_on_lockup, int, 0444);
MODULE_PARM_DESC(reset_on_lockup,
        "Do device reset on lockup (0 = no, 1 = yes, default yes)");

#define PCI_VENDOR_ID_HABANALABS        0x1da3

#define PCI_IDS_GOYA                    0x0001

static const struct pci_device_id ids[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_HABANALABS, PCI_IDS_GOYA), },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, ids);

/*
 * get_asic_type - translate device id to asic type
 *
 * @device: id of the PCI device
 *
 * Translate device id to asic type.
 * In case of unidentified device, return -1
 */
static enum hl_asic_type get_asic_type(u16 device)
{
        enum hl_asic_type asic_type;

        switch (device) {
        case PCI_IDS_GOYA:
                asic_type = ASIC_GOYA;
                break;
        default:
                asic_type = ASIC_INVALID;
                break;
        }

        return asic_type;
}

/*
 * hl_device_open - open function for habanalabs device
 *
 * @inode: pointer to inode structure
 * @filp: pointer to file structure
 *
 * Called when process opens an habanalabs device.
 */
int hl_device_open(struct inode *inode, struct file *filp)
{
        struct hl_device *hdev;
        struct hl_fpriv *hpriv;
        int rc;

        mutex_lock(&hl_devs_idr_lock);
        hdev = idr_find(&hl_devs_idr, iminor(inode));
        mutex_unlock(&hl_devs_idr_lock);

        if (!hdev) {
                pr_err("Couldn't find device %d:%d\n",
                        imajor(inode), iminor(inode));
                return -ENXIO;
        }

        mutex_lock(&hdev->fd_open_cnt_lock);

        if (hl_device_disabled_or_in_reset(hdev)) {
                dev_err_ratelimited(hdev->dev,
                        "Can't open %s because it is disabled or in reset\n",
                        dev_name(hdev->dev));
                mutex_unlock(&hdev->fd_open_cnt_lock);
                return -EPERM;
        }

        if (hdev->in_debug) {
                dev_err_ratelimited(hdev->dev,
                        "Can't open %s because it is being debugged by another user\n",
                        dev_name(hdev->dev));
                mutex_unlock(&hdev->fd_open_cnt_lock);
                return -EPERM;
        }

        if (atomic_read(&hdev->fd_open_cnt)) {
                dev_info_ratelimited(hdev->dev,
                        "Can't open %s because another user is working on it\n",
                        dev_name(hdev->dev));
                mutex_unlock(&hdev->fd_open_cnt_lock);
                return -EBUSY;
        }

        atomic_inc(&hdev->fd_open_cnt);

        mutex_unlock(&hdev->fd_open_cnt_lock);

        hpriv = kzalloc(sizeof(*hpriv), GFP_KERNEL);
        if (!hpriv) {
                rc = -ENOMEM;
                goto close_device;
        }

        hpriv->hdev = hdev;
        filp->private_data = hpriv;
        hpriv->filp = filp;
        mutex_init(&hpriv->restore_phase_mutex);
        kref_init(&hpriv->refcount);
        nonseekable_open(inode, filp);

        hl_cb_mgr_init(&hpriv->cb_mgr);
        hl_ctx_mgr_init(&hpriv->ctx_mgr);

        rc = hl_ctx_create(hdev, hpriv);
        if (rc) {
                dev_err(hdev->dev, "Failed to open FD (CTX fail)\n");
                goto out_err;
        }

        hpriv->taskpid = find_get_pid(current->pid);

        /*
         * Device is IDLE at this point so it is legal to change PLLs. There
         * is no need to check anything because if the PLL is already HIGH, the
         * set function will return without doing anything
         */
        hl_device_set_frequency(hdev, PLL_HIGH);

        hl_debugfs_add_file(hpriv);

        return 0;

out_err:
        filp->private_data = NULL;
        hl_ctx_mgr_fini(hpriv->hdev, &hpriv->ctx_mgr);
        hl_cb_mgr_fini(hpriv->hdev, &hpriv->cb_mgr);
        mutex_destroy(&hpriv->restore_phase_mutex);
        kfree(hpriv);

close_device:
        atomic_dec(&hdev->fd_open_cnt);
        return rc;
}

static void set_driver_behavior_per_device(struct hl_device *hdev)
{
        hdev->mmu_enable = 1;
        hdev->cpu_enable = 1;
        hdev->fw_loading = 1;
        hdev->cpu_queues_enable = 1;
        hdev->heartbeat = 1;

        hdev->reset_pcilink = 0;
}

/*
 * create_hdev - create habanalabs device instance
 *
 * @dev: will hold the pointer to the new habanalabs device structure
 * @pdev: pointer to the pci device
 * @asic_type: in case of simulator device, which device is it
 * @minor: in case of simulator device, the minor of the device
 *
 * Allocate memory for habanalabs device and initialize basic fields
 * Identify the ASIC type
 * Allocate ID (minor) for the device (only for real devices)
 */
int create_hdev(struct hl_device **dev, struct pci_dev *pdev,
                enum hl_asic_type asic_type, int minor)
{
        struct hl_device *hdev;
        int rc;

        *dev = NULL;

        hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
        if (!hdev)
                return -ENOMEM;

        /* First, we must find out which ASIC are we handling. This is needed
         * to configure the behavior of the driver (kernel parameters)
         */
        if (pdev) {
                hdev->asic_type = get_asic_type(pdev->device);
                if (hdev->asic_type == ASIC_INVALID) {
                        dev_err(&pdev->dev, "Unsupported ASIC\n");
                        rc = -ENODEV;
                        goto free_hdev;
                }
        } else {
                hdev->asic_type = asic_type;
        }

        hdev->major = hl_major;
        hdev->reset_on_lockup = reset_on_lockup;
        hdev->pldm = 0;

        set_driver_behavior_per_device(hdev);

        if (timeout_locked)
                hdev->timeout_jiffies = msecs_to_jiffies(timeout_locked * 1000);
        else
                hdev->timeout_jiffies = MAX_SCHEDULE_TIMEOUT;

        hdev->disabled = true;
        hdev->pdev = pdev; /* can be NULL in case of simulator device */

        /* Set default DMA mask to 32 bits */
        hdev->dma_mask = 32;

        mutex_lock(&hl_devs_idr_lock);

        if (minor == -1) {
                rc = idr_alloc(&hl_devs_idr, hdev, 0, HL_MAX_MINORS,
                                GFP_KERNEL);
        } else {
                void *old_idr = idr_replace(&hl_devs_idr, hdev, minor);

                if (IS_ERR_VALUE(old_idr)) {
                        rc = PTR_ERR(old_idr);
                        pr_err("Error %d when trying to replace minor %d\n",
                                rc, minor);
                        mutex_unlock(&hl_devs_idr_lock);
                        goto free_hdev;
                }
                rc = minor;
        }

        mutex_unlock(&hl_devs_idr_lock);

        if (rc < 0) {
                if (rc == -ENOSPC) {
                        pr_err("too many devices in the system\n");
                        rc = -EBUSY;
                }
                goto free_hdev;
        }

        hdev->id = rc;

        *dev = hdev;

        return 0;

free_hdev:
        kfree(hdev);
        return rc;
}

/*
 * destroy_hdev - destroy habanalabs device instance
 *
 * @dev: pointer to the habanalabs device structure
 *
 */
void destroy_hdev(struct hl_device *hdev)
{
        /* Remove device from the device list */
        mutex_lock(&hl_devs_idr_lock);
        idr_remove(&hl_devs_idr, hdev->id);
        mutex_unlock(&hl_devs_idr_lock);

        kfree(hdev);
}

static int hl_pmops_suspend(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct hl_device *hdev = pci_get_drvdata(pdev);

        pr_debug("Going to suspend PCI device\n");

        if (!hdev) {
                pr_err("device pointer is NULL in suspend\n");
                return 0;
        }

        return hl_device_suspend(hdev);
}

static int hl_pmops_resume(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct hl_device *hdev = pci_get_drvdata(pdev);

        pr_debug("Going to resume PCI device\n");

        if (!hdev) {
                pr_err("device pointer is NULL in resume\n");
                return 0;
        }

        return hl_device_resume(hdev);
}

/*
 * hl_pci_probe - probe PCI habanalabs devices
 *
 * @pdev: pointer to pci device
 * @id: pointer to pci device id structure
 *
 * Standard PCI probe function for habanalabs device.
 * Create a new habanalabs device and initialize it according to the
 * device's type
 */
static int hl_pci_probe(struct pci_dev *pdev,
                                const struct pci_device_id *id)
{
        struct hl_device *hdev;
        int rc;

        dev_info(&pdev->dev, HL_NAME
                 " device found [%04x:%04x] (rev %x)\n",
                 (int)pdev->vendor, (int)pdev->device, (int)pdev->revision);

        rc = create_hdev(&hdev, pdev, ASIC_INVALID, -1);
        if (rc)
                return rc;

        pci_set_drvdata(pdev, hdev);

        rc = hl_device_init(hdev, hl_class);
        if (rc) {
                dev_err(&pdev->dev, "Fatal error during habanalabs device init\n");
                rc = -ENODEV;
                goto disable_device;
        }

        return 0;

disable_device:
        pci_set_drvdata(pdev, NULL);
        destroy_hdev(hdev);

        return rc;
}

/*
 * hl_pci_remove - remove PCI habanalabs devices
 *
 * @pdev: pointer to pci device
 *
 * Standard PCI remove function for habanalabs device
 */
static void hl_pci_remove(struct pci_dev *pdev)
{
        struct hl_device *hdev;

        hdev = pci_get_drvdata(pdev);
        if (!hdev)
                return;

        hl_device_fini(hdev);
        pci_set_drvdata(pdev, NULL);

        destroy_hdev(hdev);
}

static const struct dev_pm_ops hl_pm_ops = {
        .suspend = hl_pmops_suspend,
        .resume = hl_pmops_resume,
};

static struct pci_driver hl_pci_driver = {
        .name = HL_NAME,
        .id_table = ids,
        .probe = hl_pci_probe,
        .remove = hl_pci_remove,
        .driver.pm = &hl_pm_ops,
};

/*
 * hl_init - Initialize the habanalabs kernel driver
 */
static int __init hl_init(void)
{
        int rc;
        dev_t dev;

        pr_info("loading driver\n");

        rc = alloc_chrdev_region(&dev, 0, HL_MAX_MINORS, HL_NAME);
        if (rc < 0) {
                pr_err("unable to get major\n");
                return rc;
        }

        hl_major = MAJOR(dev);

        hl_class = class_create(THIS_MODULE, HL_NAME);
        if (IS_ERR(hl_class)) {
                pr_err("failed to allocate class\n");
                rc = PTR_ERR(hl_class);
                goto remove_major;
        }

        hl_debugfs_init();

        rc = pci_register_driver(&hl_pci_driver);
        if (rc) {
                pr_err("failed to register pci device\n");
                goto remove_debugfs;
        }

        pr_debug("driver loaded\n");

        return 0;

remove_debugfs:
        hl_debugfs_fini();
        class_destroy(hl_class);
remove_major:
        unregister_chrdev_region(MKDEV(hl_major, 0), HL_MAX_MINORS);
        return rc;
}

/*
 * hl_exit - Release all resources of the habanalabs kernel driver
 */
static void __exit hl_exit(void)
{
        pci_unregister_driver(&hl_pci_driver);

        /*
         * Removing debugfs must be after all devices or simulator devices
         * have been removed because otherwise we get a bug in the
         * debugfs module for referencing NULL objects
         */
        hl_debugfs_fini();

        class_destroy(hl_class);
        unregister_chrdev_region(MKDEV(hl_major, 0), HL_MAX_MINORS);

        idr_destroy(&hl_devs_idr);

        pr_debug("driver removed\n");
}

module_init(hl_init);
module_exit(hl_exit);