// SPDX-License-Identifier: MIT
/*
 * Copyright © 2023-2024 Intel Corporation
 */

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

#include "regs/xe_bars.h"
#include "xe_assert.h"
#include "xe_device.h"
#include "xe_gt_sriov_pf_config.h"
#include "xe_gt_sriov_pf_control.h"
#include "xe_gt_sriov_printk.h"
#include "xe_guc_engine_activity.h"
#include "xe_pci_sriov.h"
#include "xe_pm.h"
#include "xe_sriov.h"
#include "xe_sriov_pf.h"
#include "xe_sriov_pf_control.h"
#include "xe_sriov_pf_helpers.h"
#include "xe_sriov_pf_provision.h"
#include "xe_sriov_pf_sysfs.h"
#include "xe_sriov_printk.h"

static void pf_reset_vfs(struct xe_device *xe, unsigned int num_vfs)
{
        unsigned int n;

        for (n = 1; n <= num_vfs; n++)
                xe_sriov_pf_control_reset_vf(xe, n);
}

static void pf_link_vfs(struct xe_device *xe, int num_vfs)
{
        struct pci_dev *pdev_pf = to_pci_dev(xe->drm.dev);
        struct device_link *link;
        struct pci_dev *pdev_vf;
        unsigned int n;

        /*
         * When both PF and VF devices are enabled on the host, during system
         * resume they are resuming in parallel.
         *
         * But PF has to complete the provision of VF first to allow any VFs to
         * successfully resume.
         *
         * Create a parent-child device link between PF and VF devices that will
         * enforce correct resume order.
         */
        for (n = 1; n <= num_vfs; n++) {
                pdev_vf = xe_pci_sriov_get_vf_pdev(pdev_pf, n);

                /* unlikely, something weird is happening, abort */
                if (!pdev_vf) {
                        xe_sriov_err(xe, "Cannot find VF%u device, aborting link%s creation!\n",
                                     n, str_plural(num_vfs));
                        break;
                }

                link = device_link_add(&pdev_vf->dev, &pdev_pf->dev,
                                       DL_FLAG_AUTOREMOVE_CONSUMER);
                /* unlikely and harmless, continue with other VFs */
                if (!link)
                        xe_sriov_notice(xe, "Failed linking VF%u\n", n);

                pci_dev_put(pdev_vf);
        }
}

static void pf_engine_activity_stats(struct xe_device *xe, unsigned int num_vfs, bool enable)
{
        struct xe_gt *gt;
        unsigned int id;
        int ret = 0;

        for_each_gt(gt, xe, id) {
                ret = xe_guc_engine_activity_function_stats(&gt->uc.guc, num_vfs, enable);
                if (ret)
                        xe_gt_sriov_info(gt, "Failed to %s engine activity function stats (%pe)\n",
                                         str_enable_disable(enable), ERR_PTR(ret));
        }
}

static int resize_vf_vram_bar(struct xe_device *xe, int num_vfs)
{
        struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
        u32 sizes;

        sizes = pci_iov_vf_bar_get_sizes(pdev, VF_LMEM_BAR, num_vfs);
        if (!sizes)
                return 0;

        return pci_iov_vf_bar_set_size(pdev, VF_LMEM_BAR, __fls(sizes));
}

static int pf_prepare_vfs_enabling(struct xe_device *xe)
{
        xe_assert(xe, IS_SRIOV_PF(xe));
        /* make sure we are not locked-down by other components */
        return xe_sriov_pf_arm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, false, NULL);
}

static void pf_finish_vfs_enabling(struct xe_device *xe)
{
        xe_assert(xe, IS_SRIOV_PF(xe));
        /* allow other components to lockdown VFs enabling */
        xe_sriov_pf_disarm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, false, NULL);
}

static int pf_enable_vfs(struct xe_device *xe, int num_vfs)
{
        struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
        int total_vfs = xe_sriov_pf_get_totalvfs(xe);
        int err;

        xe_assert(xe, IS_SRIOV_PF(xe));
        xe_assert(xe, num_vfs > 0);
        xe_assert(xe, num_vfs <= total_vfs);
        xe_sriov_dbg(xe, "enabling %u VF%s\n", num_vfs, str_plural(num_vfs));

        err = xe_sriov_pf_wait_ready(xe);
        if (err)
                goto out;

        err = pf_prepare_vfs_enabling(xe);
        if (err)
                goto out;

        /*
         * We must hold additional reference to the runtime PM to keep PF in D0
         * during VFs lifetime, as our VFs do not implement the PM capability.
         *
         * With PF being in D0 state, all VFs will also behave as in D0 state.
         * This will also keep GuC alive with all VFs' configurations.
         *
         * We will release this additional PM reference in pf_disable_vfs().
         */
        xe_pm_runtime_get_noresume(xe);

        err = xe_sriov_pf_provision_vfs(xe, num_vfs);
        if (err < 0)
                goto failed;

        if (IS_DGFX(xe)) {
                err = resize_vf_vram_bar(xe, num_vfs);
                if (err)
                        xe_sriov_info(xe, "Failed to set VF LMEM BAR size: %d\n", err);
        }

        err = pci_enable_sriov(pdev, num_vfs);
        if (err < 0)
                goto failed;

        pf_link_vfs(xe, num_vfs);

        xe_sriov_info(xe, "Enabled %u of %u VF%s\n",
                      num_vfs, total_vfs, str_plural(total_vfs));

        xe_sriov_pf_sysfs_link_vfs(xe, num_vfs);

        pf_engine_activity_stats(xe, num_vfs, true);

        return num_vfs;

failed:
        xe_sriov_pf_unprovision_vfs(xe, num_vfs);
        xe_pm_runtime_put(xe);
        pf_finish_vfs_enabling(xe);
out:
        xe_sriov_notice(xe, "Failed to enable %u VF%s (%pe)\n",
                        num_vfs, str_plural(num_vfs), ERR_PTR(err));
        return err;
}

static int pf_disable_vfs(struct xe_device *xe)
{
        struct device *dev = xe->drm.dev;
        struct pci_dev *pdev = to_pci_dev(dev);
        u16 num_vfs = pci_num_vf(pdev);

        xe_assert(xe, IS_SRIOV_PF(xe));
        xe_sriov_dbg(xe, "disabling %u VF%s\n", num_vfs, str_plural(num_vfs));

        if (!num_vfs)
                return 0;

        pf_engine_activity_stats(xe, num_vfs, false);

        xe_sriov_pf_sysfs_unlink_vfs(xe, num_vfs);

        pci_disable_sriov(pdev);

        xe_sriov_pf_reprovision_default(xe);

        pf_reset_vfs(xe, num_vfs);

        xe_sriov_pf_unprovision_vfs(xe, num_vfs);

        /* not needed anymore - see pf_enable_vfs() */
        xe_pm_runtime_put(xe);

        pf_finish_vfs_enabling(xe);

        xe_sriov_info(xe, "Disabled %u VF%s\n", num_vfs, str_plural(num_vfs));
        return 0;
}

/**
 * xe_pci_sriov_configure - Configure SR-IOV (enable/disable VFs).
 * @pdev: the &pci_dev
 * @num_vfs: number of VFs to enable or zero to disable all VFs
 *
 * This is the Xe implementation of struct pci_driver.sriov_configure callback.
 *
 * This callback will be called by the PCI subsystem to enable or disable SR-IOV
 * Virtual Functions (VFs) as requested by the used via the PCI sysfs interface.
 *
 * Return: number of configured VFs or a negative error code on failure.
 */
int xe_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
{
        struct xe_device *xe = pdev_to_xe_device(pdev);

        if (!IS_SRIOV_PF(xe))
                return -ENODEV;

        if (num_vfs < 0)
                return -EINVAL;

        if (num_vfs > xe_sriov_pf_get_totalvfs(xe))
                return -ERANGE;

        if (num_vfs && pci_num_vf(pdev))
                return -EBUSY;

        guard(xe_pm_runtime)(xe);
        if (num_vfs > 0)
                return pf_enable_vfs(xe, num_vfs);
        else
                return pf_disable_vfs(xe);
}

/**
 * xe_pci_sriov_get_vf_pdev() - Lookup the VF's PCI device using the VF identifier.
 * @pdev: the PF's &pci_dev
 * @vfid: VF identifier (1-based)
 *
 * The caller must decrement the reference count by calling pci_dev_put().
 *
 * Return: the VF's &pci_dev or NULL if the VF device was not found.
 */
struct pci_dev *xe_pci_sriov_get_vf_pdev(struct pci_dev *pdev, unsigned int vfid)
{
        struct xe_device *xe = pdev_to_xe_device(pdev);

        xe_assert(xe, dev_is_pf(&pdev->dev));
        xe_assert(xe, vfid);
        xe_assert(xe, vfid <= pci_sriov_get_totalvfs(pdev));

        return pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus),
                                           pdev->bus->number,
                                           pci_iov_virtfn_devfn(pdev, vfid - 1));
}