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

#include <drm/drm_managed.h>

#include "abi/guc_actions_sriov_abi.h"

#include "xe_device.h"
#include "xe_gt.h"
#include "xe_gt_sriov_pf.h"
#include "xe_gt_sriov_pf_config.h"
#include "xe_gt_sriov_pf_control.h"
#include "xe_gt_sriov_pf_helpers.h"
#include "xe_gt_sriov_pf_migration.h"
#include "xe_gt_sriov_pf_monitor.h"
#include "xe_gt_sriov_printk.h"
#include "xe_guc_ct.h"
#include "xe_sriov.h"
#include "xe_sriov_packet.h"
#include "xe_sriov_packet_types.h"
#include "xe_sriov_pf_control.h"
#include "xe_sriov_pf_migration.h"
#include "xe_sriov_pf_service.h"
#include "xe_tile.h"

static const char *control_cmd_to_string(u32 cmd)
{
        switch (cmd) {
        case GUC_PF_TRIGGER_VF_PAUSE:
                return "PAUSE";
        case GUC_PF_TRIGGER_VF_RESUME:
                return "RESUME";
        case GUC_PF_TRIGGER_VF_STOP:
                return "STOP";
        case GUC_PF_TRIGGER_VF_FLR_START:
                return "FLR_START";
        case GUC_PF_TRIGGER_VF_FLR_FINISH:
                return "FLR_FINISH";
        default:
                return "<unknown>";
        }
}

static int guc_action_vf_control_cmd(struct xe_guc *guc, u32 vfid, u32 cmd)
{
        u32 request[PF2GUC_VF_CONTROL_REQUEST_MSG_LEN] = {
                FIELD_PREP(GUC_HXG_MSG_0_ORIGIN, GUC_HXG_ORIGIN_HOST) |
                FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_REQUEST) |
                FIELD_PREP(GUC_HXG_REQUEST_MSG_0_ACTION, GUC_ACTION_PF2GUC_VF_CONTROL),
                FIELD_PREP(PF2GUC_VF_CONTROL_REQUEST_MSG_1_VFID, vfid),
                FIELD_PREP(PF2GUC_VF_CONTROL_REQUEST_MSG_2_COMMAND, cmd),
        };
        int ret;

        ret = xe_guc_ct_send_block(&guc->ct, request, ARRAY_SIZE(request));
        return ret > 0 ? -EPROTO : ret;
}

static int pf_send_vf_control_cmd(struct xe_gt *gt, unsigned int vfid, u32 cmd)
{
        int err;

        xe_gt_assert(gt, vfid != PFID);
        xe_gt_sriov_dbg_verbose(gt, "sending VF%u control command %s\n",
                                vfid, control_cmd_to_string(cmd));

        err = guc_action_vf_control_cmd(&gt->uc.guc, vfid, cmd);
        if (unlikely(err))
                xe_gt_sriov_err(gt, "VF%u control command %s failed (%pe)\n",
                                vfid, control_cmd_to_string(cmd), ERR_PTR(err));
        return err;
}

static int pf_send_vf_pause(struct xe_gt *gt, unsigned int vfid)
{
        return pf_send_vf_control_cmd(gt, vfid, GUC_PF_TRIGGER_VF_PAUSE);
}

static int pf_send_vf_resume(struct xe_gt *gt, unsigned int vfid)
{
        return pf_send_vf_control_cmd(gt, vfid, GUC_PF_TRIGGER_VF_RESUME);
}

static int pf_send_vf_stop(struct xe_gt *gt, unsigned int vfid)
{
        return pf_send_vf_control_cmd(gt, vfid, GUC_PF_TRIGGER_VF_STOP);
}

static int pf_send_vf_flr_start(struct xe_gt *gt, unsigned int vfid)
{
        return pf_send_vf_control_cmd(gt, vfid, GUC_PF_TRIGGER_VF_FLR_START);
}

static int pf_send_vf_flr_finish(struct xe_gt *gt, unsigned int vfid)
{
        return pf_send_vf_control_cmd(gt, vfid, GUC_PF_TRIGGER_VF_FLR_FINISH);
}

/**
 * DOC: The VF state machine
 *
 * The simplified VF state machine could be presented as::
 *
 *                     pause--------------------------o
 *                    /                               |
 *                   /                                v
 *            (READY)<------------------resume-----(PAUSED)
 *               ^   \                             /    /
 *               |    \                           /    /
 *               |     stop---->(STOPPED)<----stop    /
 *               |                  /                /
 *               |                 /                /
 *               o--------<-----flr                /
 *                \                               /
 *                 o------<--------------------flr
 *
 * Where:
 *
 * * READY - represents a state in which VF is fully operable
 * * PAUSED - represents a state in which VF activity is temporarily suspended
 * * STOPPED - represents a state in which VF activity is definitely halted
 * * pause - represents a request to temporarily suspend VF activity
 * * resume - represents a request to resume VF activity
 * * stop - represents a request to definitely halt VF activity
 * * flr - represents a request to perform VF FLR to restore VF activity
 *
 * However, each state transition requires additional steps that involves
 * communication with GuC that might fail or be interrupted by other requests::
 *
 *                         .................................WIP....
 *                         :                                      :
 *                pause--------------------->PAUSE_WIP----------------------------o
 *               /         :                /         \           :               |
 *              /          :    o----<---stop          flr--o     :               |
 *             /           :    |           \         /     |     :               V
 *      (READY,RESUMED)<--------+------------RESUME_WIP<----+--<-----resume--(PAUSED)
 *        ^ \  \           :    |                           |     :          /   /
 *        |  \  \          :    |                           |     :         /   /
 *        |   \  \         :    |                           |     :        /   /
 *        |    \  \        :    o----<----------------------+--<-------stop   /
 *        |     \  \       :    |                           |     :          /
 *        |      \  \      :    V                           |     :         /
 *        |       \  stop----->STOP_WIP---------flr--->-----o     :        /
 *        |        \       :    |                           |     :       /
 *        |         \      :    |                           V     :      /
 *        |          flr--------+----->----------------->FLR_WIP<-----flr
 *        |                :    |                        /  ^     :
 *        |                :    |                       /   |     :
 *        o--------<-------:----+-----<----------------o    |     :
 *                         :    |                           |     :
 *                         :....|...........................|.....:
 *                              |                           |
 *                              V                           |
 *                           (STOPPED)--------------------flr
 *
 * For details about each internal WIP state machine see:
 *
 * * `The VF PAUSE state machine`_
 * * `The VF RESUME state machine`_
 * * `The VF STOP state machine`_
 * * `The VF FLR state machine`_
 */

#ifdef CONFIG_DRM_XE_DEBUG_SRIOV
static const char *control_bit_to_string(enum xe_gt_sriov_control_bits bit)
{
        switch (bit) {
#define CASE2STR(_X) \
        case XE_GT_SRIOV_STATE_##_X: return #_X
        CASE2STR(WIP);
        CASE2STR(FLR_WIP);
        CASE2STR(FLR_SEND_START);
        CASE2STR(FLR_WAIT_GUC);
        CASE2STR(FLR_GUC_DONE);
        CASE2STR(FLR_SYNC);
        CASE2STR(FLR_RESET_CONFIG);
        CASE2STR(FLR_RESET_DATA);
        CASE2STR(FLR_RESET_MMIO);
        CASE2STR(FLR_SEND_FINISH);
        CASE2STR(FLR_FAILED);
        CASE2STR(PAUSE_WIP);
        CASE2STR(PAUSE_SEND_PAUSE);
        CASE2STR(PAUSE_WAIT_GUC);
        CASE2STR(PAUSE_GUC_DONE);
        CASE2STR(PAUSE_FAILED);
        CASE2STR(PAUSED);
        CASE2STR(SAVE_WIP);
        CASE2STR(SAVE_PROCESS_DATA);
        CASE2STR(SAVE_WAIT_DATA);
        CASE2STR(SAVE_DATA_DONE);
        CASE2STR(SAVE_FAILED);
        CASE2STR(SAVED);
        CASE2STR(RESTORE_WIP);
        CASE2STR(RESTORE_PROCESS_DATA);
        CASE2STR(RESTORE_WAIT_DATA);
        CASE2STR(RESTORE_DATA_DONE);
        CASE2STR(RESTORE_FAILED);
        CASE2STR(RESTORED);
        CASE2STR(RESUME_WIP);
        CASE2STR(RESUME_SEND_RESUME);
        CASE2STR(RESUME_FAILED);
        CASE2STR(RESUMED);
        CASE2STR(STOP_WIP);
        CASE2STR(STOP_SEND_STOP);
        CASE2STR(STOP_FAILED);
        CASE2STR(STOPPED);
        CASE2STR(MISMATCH);
#undef  CASE2STR
        default: return "?";
        }
}
#endif

static unsigned long pf_get_default_timeout(enum xe_gt_sriov_control_bits bit)
{
        switch (bit) {
        case XE_GT_SRIOV_STATE_FLR_WAIT_GUC:
        case XE_GT_SRIOV_STATE_PAUSE_WAIT_GUC:
                return HZ / 2;
        case XE_GT_SRIOV_STATE_FLR_WIP:
        case XE_GT_SRIOV_STATE_FLR_RESET_CONFIG:
                return 5 * HZ;
        case XE_GT_SRIOV_STATE_RESTORE_WIP:
                return 20 * HZ;
        default:
                return HZ;
        }
}

static struct xe_gt_sriov_control_state *pf_pick_vf_control(struct xe_gt *gt, unsigned int vfid)
{
        xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
        xe_gt_assert(gt, vfid <= xe_gt_sriov_pf_get_totalvfs(gt));

        return &gt->sriov.pf.vfs[vfid].control;
}

static unsigned long *pf_peek_vf_state(struct xe_gt *gt, unsigned int vfid)
{
        struct xe_gt_sriov_control_state *cs = pf_pick_vf_control(gt, vfid);

        return cs->state;
}

static bool pf_check_vf_state(struct xe_gt *gt, unsigned int vfid,
                              enum xe_gt_sriov_control_bits bit)
{
        return test_bit(bit, pf_peek_vf_state(gt, vfid));
}

static void pf_dump_vf_state(struct xe_gt *gt, unsigned int vfid)
{
        unsigned long state = *pf_peek_vf_state(gt, vfid);
        enum xe_gt_sriov_control_bits bit;

        if (state) {
                xe_gt_sriov_dbg_verbose(gt, "VF%u state %#lx%s%*pbl\n",
                                        vfid, state, state ? " bits " : "",
                                        (int)BITS_PER_LONG, &state);
                for_each_set_bit(bit, &state, BITS_PER_LONG)
                        xe_gt_sriov_dbg_verbose(gt, "VF%u state %s(%d)\n",
                                                vfid, control_bit_to_string(bit), bit);
        } else {
                xe_gt_sriov_dbg_verbose(gt, "VF%u state READY\n", vfid);
        }
}

static bool pf_expect_vf_state(struct xe_gt *gt, unsigned int vfid,
                               enum xe_gt_sriov_control_bits bit)
{
        bool result = pf_check_vf_state(gt, vfid, bit);

        if (unlikely(!result))
                pf_dump_vf_state(gt, vfid);

        return result;
}

static bool pf_expect_vf_not_state(struct xe_gt *gt, unsigned int vfid,
                                   enum xe_gt_sriov_control_bits bit)
{
        bool result = !pf_check_vf_state(gt, vfid, bit);

        if (unlikely(!result))
                pf_dump_vf_state(gt, vfid);

        return result;
}

static void pf_track_vf_state(struct xe_gt *gt, unsigned int vfid,
                              enum xe_gt_sriov_control_bits bit,
                              const char *what)
{
        xe_gt_sriov_dbg_verbose(gt, "VF%u state %s(%d) %s\n",
                                vfid, control_bit_to_string(bit), bit, what);
}

static bool pf_enter_vf_state(struct xe_gt *gt, unsigned int vfid,
                              enum xe_gt_sriov_control_bits bit)
{
        if (!test_and_set_bit(bit, pf_peek_vf_state(gt, vfid))) {
                pf_track_vf_state(gt, vfid, bit, "enter");
                return true;
        }
        return false;
}

static bool pf_exit_vf_state(struct xe_gt *gt, unsigned int vfid,
                             enum xe_gt_sriov_control_bits bit)
{
        if (test_and_clear_bit(bit, pf_peek_vf_state(gt, vfid))) {
                pf_track_vf_state(gt, vfid, bit, "exit");
                return true;
        }
        return false;
}

static void pf_escape_vf_state(struct xe_gt *gt, unsigned int vfid,
                               enum xe_gt_sriov_control_bits bit)
{
        if (pf_exit_vf_state(gt, vfid, bit))
                xe_gt_sriov_dbg_verbose(gt, "VF%u state %s(%d) escaped by %ps\n",
                                        vfid, control_bit_to_string(bit), bit,
                                        __builtin_return_address(0));
}

static void pf_enter_vf_mismatch(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_MISMATCH)) {
                xe_gt_sriov_dbg(gt, "VF%u state mismatch detected by %ps\n",
                                vfid, __builtin_return_address(0));
                pf_dump_vf_state(gt, vfid);
        }
}

static void pf_exit_vf_mismatch(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_MISMATCH))
                xe_gt_sriov_dbg(gt, "VF%u state mismatch cleared by %ps\n",
                                vfid, __builtin_return_address(0));

        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_FAILED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_FAILED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_FAILED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_FAILED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_FAILED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_FAILED);
}

#define pf_enter_vf_state_machine_bug(gt, vfid) ({      \
        pf_enter_vf_mismatch((gt), (vfid));             \
})

static void pf_queue_control_worker(struct xe_gt *gt)
{
        struct xe_device *xe = gt_to_xe(gt);

        xe_gt_assert(gt, IS_SRIOV_PF(xe));

        queue_work(xe->sriov.wq, &gt->sriov.pf.control.worker);
}

static void pf_queue_vf(struct xe_gt *gt, unsigned int vfid)
{
        struct xe_gt_sriov_pf_control *pfc = &gt->sriov.pf.control;

        xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));

        spin_lock(&pfc->lock);
        list_move_tail(&gt->sriov.pf.vfs[vfid].control.link, &pfc->list);
        spin_unlock(&pfc->lock);

        pf_queue_control_worker(gt);
}

static void pf_exit_vf_flr_wip(struct xe_gt *gt, unsigned int vfid);
static void pf_exit_vf_stop_wip(struct xe_gt *gt, unsigned int vfid);
static void pf_exit_vf_save_wip(struct xe_gt *gt, unsigned int vfid);
static void pf_exit_vf_restore_wip(struct xe_gt *gt, unsigned int vfid);
static void pf_exit_vf_pause_wip(struct xe_gt *gt, unsigned int vfid);
static void pf_exit_vf_resume_wip(struct xe_gt *gt, unsigned int vfid);

static bool pf_enter_vf_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_WIP)) {
                struct xe_gt_sriov_control_state *cs = pf_pick_vf_control(gt, vfid);

                reinit_completion(&cs->done);
                return true;
        }
        return false;
}

static void pf_exit_vf_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_WIP)) {
                struct xe_gt_sriov_control_state *cs = pf_pick_vf_control(gt, vfid);

                pf_exit_vf_flr_wip(gt, vfid);
                pf_exit_vf_stop_wip(gt, vfid);
                pf_exit_vf_save_wip(gt, vfid);
                pf_exit_vf_restore_wip(gt, vfid);
                pf_exit_vf_pause_wip(gt, vfid);
                pf_exit_vf_resume_wip(gt, vfid);

                complete_all(&cs->done);
        }
}

static int pf_wait_vf_wip_done(struct xe_gt *gt, unsigned int vfid, unsigned long timeout)
{
        struct xe_gt_sriov_control_state *cs = pf_pick_vf_control(gt, vfid);

        return wait_for_completion_timeout(&cs->done, timeout) ? 0 : -ETIMEDOUT;
}

static void pf_enter_vf_ready(struct xe_gt *gt, unsigned int vfid)
{
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOPPED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUMED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORED);
        pf_exit_vf_mismatch(gt, vfid);
        pf_exit_vf_wip(gt, vfid);
}

/**
 * DOC: The VF PAUSE state machine
 *
 * The VF PAUSE state machine looks like::
 *
 *       (READY,RESUMED)<-------------<---------------------o---------o
 *          |                                                \         \
 *         pause                                              \         \
 *          |                                                  \         \
 *      ....V...........................PAUSE_WIP........       \         \
 *      :    \                                          :        o         \
 *      :     \   o------<-----busy                     :        |          \
 *      :      \ /              /                       :        |           |
 *      :       PAUSE_SEND_PAUSE ---failed--->----------o--->(PAUSE_FAILED)  |
 *      :        |              \                       :        |           |
 *      :      acked             rejected---->----------o--->(MISMATCH)     /
 *      :        |                                      :                  /
 *      :        v                                      :                 /
 *      :       PAUSE_WAIT_GUC                          :                /
 *      :        |                                      :               /
 *      :       done                                    :              /
 *      :        |                                      :             /
 *      :        v                                      :            /
 *      :       PAUSE_GUC_DONE                          o-----restart
 *      :        |                                      :
 *      :        |   o---<--busy                        :
 *      :       /                                       :
 *      :      /                                        :
 *      :     /                                         :
 *      :....o..............o...............o...........:
 *           |              |               |
 *        completed        flr             stop
 *           |              |               |
 *           V         .....V.....    ......V.....
 *       (PAUSED)      : FLR_WIP :    : STOP_WIP :
 *                     :.........:    :..........:
 *
 * For the full state machine view, see `The VF state machine`_.
 */

static void pf_exit_vf_pause_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_WIP)) {
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_SEND_PAUSE);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_WAIT_GUC);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_GUC_DONE);
        }
}

static void pf_enter_vf_paused(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUMED);
        pf_exit_vf_mismatch(gt, vfid);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_pause_completed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_paused(gt, vfid);
}

static void pf_enter_vf_pause_failed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_FAILED);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_pause_rejected(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_mismatch(gt, vfid);
        pf_enter_vf_pause_failed(gt, vfid);
}

static bool pf_exit_vf_pause_guc_done(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_GUC_DONE))
                return false;

        pf_enter_vf_pause_completed(gt, vfid);
        return true;
}

static void pf_enter_vf_pause_guc_done(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_GUC_DONE))
                pf_queue_vf(gt, vfid);
}

static void pf_enter_pause_wait_guc(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_WAIT_GUC))
                pf_enter_vf_state_machine_bug(gt, vfid);
}

static bool pf_exit_pause_wait_guc(struct xe_gt *gt, unsigned int vfid)
{
        return pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_WAIT_GUC);
}

static void pf_enter_vf_pause_send_pause(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_SEND_PAUSE))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static bool pf_exit_vf_pause_send_pause(struct xe_gt *gt, unsigned int vfid)
{
        int err;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_SEND_PAUSE))
                return false;

        /* GuC may actually send a PAUSE_DONE before we get a RESPONSE */
        pf_enter_pause_wait_guc(gt, vfid);

        err = pf_send_vf_pause(gt, vfid);
        if (err) {
                /* send failed, so we shouldn't expect PAUSE_DONE from GuC */
                pf_exit_pause_wait_guc(gt, vfid);

                if (err == -EBUSY)
                        pf_enter_vf_pause_send_pause(gt, vfid);
                else if (err == -EIO)
                        pf_enter_vf_pause_rejected(gt, vfid);
                else
                        pf_enter_vf_pause_failed(gt, vfid);
        } else {
                /*
                 * we have already moved to WAIT_GUC, maybe even to GUC_DONE
                 * but since GuC didn't complain, we may clear MISMATCH
                 */
                pf_exit_vf_mismatch(gt, vfid);
        }

        return true;
}

static bool pf_enter_vf_pause_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_WIP)) {
                pf_enter_vf_wip(gt, vfid);
                pf_enter_vf_pause_send_pause(gt, vfid);
                return true;
        }

        return false;
}

/**
 * xe_gt_sriov_pf_control_pause_vf - Pause a VF.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_pause_vf(struct xe_gt *gt, unsigned int vfid)
{
        unsigned long timeout = pf_get_default_timeout(XE_GT_SRIOV_STATE_PAUSE_WIP);
        int err;

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOPPED)) {
                xe_gt_sriov_dbg(gt, "VF%u is stopped!\n", vfid);
                return -EPERM;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED)) {
                xe_gt_sriov_dbg(gt, "VF%u was already paused!\n", vfid);
                return -ESTALE;
        }

        if (!pf_enter_vf_pause_wip(gt, vfid)) {
                xe_gt_sriov_dbg(gt, "VF%u pause already in progress!\n", vfid);
                return -EALREADY;
        }

        err = pf_wait_vf_wip_done(gt, vfid, timeout);
        if (err) {
                xe_gt_sriov_dbg(gt, "VF%u pause didn't finish in %u ms (%pe)\n",
                                vfid, jiffies_to_msecs(timeout), ERR_PTR(err));
                return err;
        }

        if (pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED)) {
                xe_gt_sriov_dbg(gt, "VF%u paused!\n", vfid);
                return 0;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_FAILED)) {
                xe_gt_sriov_dbg(gt, "VF%u pause failed!\n", vfid);
                return -EIO;
        }

        xe_gt_sriov_dbg(gt, "VF%u pause was canceled!\n", vfid);
        return -ECANCELED;
}

/**
 * DOC: The VF RESUME state machine
 *
 * The VF RESUME state machine looks like::
 *
 *       (PAUSED)<-----------------<------------------------o
 *          |                                                \
 *         resume                                             \
 *          |                                                  \
 *      ....V............................RESUME_WIP......       \
 *      :    \                                          :        o
 *      :     \   o-------<-----busy                    :        |
 *      :      \ /                /                     :        |
 *      :       RESUME_SEND_RESUME ---failed--->--------o--->(RESUME_FAILED)
 *      :       /                \                      :        |
 *      :    acked                rejected---->---------o--->(MISMATCH)
 *      :     /                                         :
 *      :....o..............o...............o.....o.....:
 *           |              |               |      \
 *        completed        flr            stop      restart-->(READY)
 *           |              |               |
 *           V         .....V.....    ......V.....
 *       (RESUMED)     : FLR_WIP :    : STOP_WIP :
 *                     :.........:    :..........:
 *
 * For the full state machine view, see `The VF state machine`_.
 */

static void pf_exit_vf_resume_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_WIP))
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_SEND_RESUME);
}

static void pf_enter_vf_resumed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUMED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORED);
        pf_exit_vf_mismatch(gt, vfid);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_resume_completed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_resumed(gt, vfid);
}

static void pf_enter_vf_resume_failed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_FAILED);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_resume_rejected(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_mismatch(gt, vfid);
        pf_enter_vf_resume_failed(gt, vfid);
}

static void pf_enter_vf_resume_send_resume(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_SEND_RESUME))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static bool pf_exit_vf_resume_send_resume(struct xe_gt *gt, unsigned int vfid)
{
        int err;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_SEND_RESUME))
                return false;

        err = pf_send_vf_resume(gt, vfid);
        if (err == -EBUSY)
                pf_enter_vf_resume_send_resume(gt, vfid);
        else if (err == -EIO)
                pf_enter_vf_resume_rejected(gt, vfid);
        else if (err)
                pf_enter_vf_resume_failed(gt, vfid);
        else
                pf_enter_vf_resume_completed(gt, vfid);
        return true;
}

static bool pf_enter_vf_resume_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_WIP)) {
                pf_enter_vf_wip(gt, vfid);
                pf_enter_vf_resume_send_resume(gt, vfid);
                return true;
        }

        return false;
}

/**
 * xe_gt_sriov_pf_control_resume_vf - Resume a VF.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_resume_vf(struct xe_gt *gt, unsigned int vfid)
{
        unsigned long timeout = pf_get_default_timeout(XE_GT_SRIOV_STATE_RESUME_WIP);
        int err;

        if (!pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED)) {
                xe_gt_sriov_dbg(gt, "VF%u is not paused!\n", vfid);
                return -EPERM;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WIP)) {
                xe_gt_sriov_dbg(gt, "VF%u save is in progress!\n", vfid);
                return -EBUSY;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WIP)) {
                xe_gt_sriov_dbg(gt, "VF%u restore is in progress!\n", vfid);
                return -EBUSY;
        }

        if (!pf_enter_vf_resume_wip(gt, vfid)) {
                xe_gt_sriov_dbg(gt, "VF%u resume already in progress!\n", vfid);
                return -EALREADY;
        }

        err = pf_wait_vf_wip_done(gt, vfid, timeout);
        if (err)
                return err;

        if (pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUMED)) {
                xe_gt_sriov_dbg(gt, "VF%u resumed!\n", vfid);
                return 0;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUME_FAILED)) {
                xe_gt_sriov_dbg(gt, "VF%u resume failed!\n", vfid);
                return -EIO;
        }

        xe_gt_sriov_dbg(gt, "VF%u resume was canceled!\n", vfid);
        return -ECANCELED;
}

/**
 * DOC: The VF SAVE state machine
 *
 * SAVE extends the PAUSED state.
 *
 * The VF SAVE state machine looks like::
 *
 *  ....PAUSED....................................................
 *  :                                                            :
 *  :     (O)<---------o                                         :
 *  :      |            \                                        :
 *  :    save          (SAVED)    (SAVE_FAILED)                  :
 *  :      |               ^           ^                         :
 *  :      |               |           |                         :
 *  :  ....V...............o...........o......SAVE_WIP.........  :
 *  :  :   |               |           |                      :  :
 *  :  :   |             empty         |                      :  :
 *  :  :   |               |           |                      :  :
 *  :  :   |               |           |                      :  :
 *  :  :   |           DATA_DONE       |                      :  :
 *  :  :   |               ^           |                      :  :
 *  :  :   |               |        error                     :  :
 *  :  :   |            no_data       /                       :  :
 *  :  :   |              /          /                        :  :
 *  :  :   |             /          /                         :  :
 *  :  :   |            /          /                          :  :
 *  :  :   o---------->PROCESS_DATA<----consume               :  :
 *  :  :                \                      \              :  :
 *  :  :                 \                      \             :  :
 *  :  :                  \                      \            :  :
 *  :  :                   ring_full----->WAIT_DATA           :  :
 *  :  :                                                      :  :
 *  :  :......................................................:  :
 *  :............................................................:
 *
 * For the full state machine view, see `The VF state machine`_.
 */

static void pf_exit_vf_save_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WIP)) {
                xe_gt_sriov_pf_migration_ring_free(gt, vfid);

                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_PROCESS_DATA);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WAIT_DATA);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_DONE);
        }
}

static void pf_enter_vf_saved(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVED))
                pf_enter_vf_state_machine_bug(gt, vfid);

        xe_gt_sriov_dbg(gt, "VF%u saved!\n", vfid);

        pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED);
        pf_exit_vf_mismatch(gt, vfid);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_save_failed(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_FAILED))
                pf_enter_vf_state_machine_bug(gt, vfid);

        wake_up_all(xe_sriov_pf_migration_waitqueue(gt_to_xe(gt), vfid));

        pf_exit_vf_wip(gt, vfid);
}

static int pf_handle_vf_save_data(struct xe_gt *gt, unsigned int vfid)
{
        int ret;

        if (xe_gt_sriov_pf_migration_save_data_pending(gt, vfid,
                                                       XE_SRIOV_PACKET_TYPE_GUC)) {
                ret = xe_gt_sriov_pf_migration_guc_save(gt, vfid);
                if (ret)
                        return ret;

                xe_gt_sriov_pf_migration_save_data_complete(gt, vfid,
                                                            XE_SRIOV_PACKET_TYPE_GUC);

                return -EAGAIN;
        }

        if (xe_gt_sriov_pf_migration_save_data_pending(gt, vfid,
                                                       XE_SRIOV_PACKET_TYPE_GGTT)) {
                ret = xe_gt_sriov_pf_migration_ggtt_save(gt, vfid);
                if (ret)
                        return ret;

                xe_gt_sriov_pf_migration_save_data_complete(gt, vfid,
                                                            XE_SRIOV_PACKET_TYPE_GGTT);

                return -EAGAIN;
        }

        if (xe_gt_sriov_pf_migration_save_data_pending(gt, vfid,
                                                       XE_SRIOV_PACKET_TYPE_MMIO)) {
                ret = xe_gt_sriov_pf_migration_mmio_save(gt, vfid);
                if (ret)
                        return ret;

                xe_gt_sriov_pf_migration_save_data_complete(gt, vfid,
                                                            XE_SRIOV_PACKET_TYPE_MMIO);

                return -EAGAIN;
        }

        if (xe_gt_sriov_pf_migration_save_data_pending(gt, vfid,
                                                       XE_SRIOV_PACKET_TYPE_VRAM)) {
                ret = xe_gt_sriov_pf_migration_vram_save(gt, vfid);
                if (ret == -EAGAIN)
                        return -EAGAIN;
                else if (ret)
                        return ret;

                xe_gt_sriov_pf_migration_save_data_complete(gt, vfid,
                                                            XE_SRIOV_PACKET_TYPE_VRAM);

                return -EAGAIN;
        }

        return 0;
}

static bool pf_handle_vf_save(struct xe_gt *gt, unsigned int vfid)
{
        int ret;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_PROCESS_DATA))
                return false;

        if (xe_gt_sriov_pf_migration_ring_full(gt, vfid)) {
                pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WAIT_DATA);
                return true;
        }

        ret = pf_handle_vf_save_data(gt, vfid);
        if (ret == -EAGAIN)
                pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_PROCESS_DATA);
        else if (ret)
                pf_enter_vf_save_failed(gt, vfid);
        else
                pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_DONE);

        return true;
}

static void pf_exit_vf_save_wait_data(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WAIT_DATA))
                return;

        pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_PROCESS_DATA);
        pf_queue_vf(gt, vfid);
}

static bool pf_enter_vf_save_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WIP)) {
                xe_gt_sriov_pf_migration_save_init(gt, vfid);
                pf_enter_vf_wip(gt, vfid);
                pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_PROCESS_DATA);
                pf_queue_vf(gt, vfid);
                return true;
        }

        return false;
}

/**
 * xe_gt_sriov_pf_control_check_save_data_done() - Check if all save migration data was produced.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: true if all migration data was produced, false otherwise.
 */
bool xe_gt_sriov_pf_control_check_save_data_done(struct xe_gt *gt, unsigned int vfid)
{
        return pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_DONE);
}

/**
 * xe_gt_sriov_pf_control_check_save_failed() - Check if save processing has failed.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: true if save processing failed, false otherwise.
 */
bool xe_gt_sriov_pf_control_check_save_failed(struct xe_gt *gt, unsigned int vfid)
{
        return pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_FAILED);
}

/**
 * xe_gt_sriov_pf_control_process_save_data() - Queue VF save migration data processing.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_process_save_data(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_expect_vf_not_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_FAILED))
                return -EIO;

        pf_exit_vf_save_wait_data(gt, vfid);

        return 0;
}

/**
 * xe_gt_sriov_pf_control_trigger_save_vf() - Start an SR-IOV VF migration data save sequence.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_trigger_save_vf(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOPPED)) {
                xe_gt_sriov_dbg(gt, "VF%u is stopped!\n", vfid);
                return -EPERM;
        }

        if (!pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED)) {
                xe_gt_sriov_dbg(gt, "VF%u is not paused!\n", vfid);
                return -EPERM;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WIP)) {
                xe_gt_sriov_dbg(gt, "VF%u restore is in progress!\n", vfid);
                return -EBUSY;
        }

        if (!pf_enter_vf_save_wip(gt, vfid)) {
                xe_gt_sriov_dbg(gt, "VF%u save already in progress!\n", vfid);
                return -EALREADY;
        }

        return 0;
}

/**
 * xe_gt_sriov_pf_control_finish_save_vf() - Complete a VF migration data save sequence.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_finish_save_vf(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_DONE)) {
                xe_gt_sriov_err(gt, "VF%u save is still in progress!\n", vfid);
                return -EIO;
        }

        pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_DONE);
        pf_enter_vf_saved(gt, vfid);

        return 0;
}

/**
 * DOC: The VF RESTORE state machine
 *
 * RESTORE extends the PAUSED state.
 *
 * The VF RESTORE state machine looks like::
 *
 *  ....PAUSED....................................................
 *  :                                                            :
 *  :     (O)<---------o                                         :
 *  :      |            \                                        :
 *  :    restore      (RESTORED)  (RESTORE_FAILED)               :
 *  :      |               ^           ^                         :
 *  :      |               |           |                         :
 *  :  ....V...............o...........o......RESTORE_WIP......  :
 *  :  :   |               |           |                      :  :
 *  :  :   |             empty         |                      :  :
 *  :  :   |               |           |                      :  :
 *  :  :   |               |           |                      :  :
 *  :  :   |           DATA_DONE       |                      :  :
 *  :  :   |               ^           |                      :  :
 *  :  :   |               |        error                     :  :
 *  :  :   |           trailer        /                       :  :
 *  :  :   |              /          /                        :  :
 *  :  :   |             /          /                         :  :
 *  :  :   |            /          /                          :  :
 *  :  :   o---------->PROCESS_DATA<----produce               :  :
 *  :  :                \                      \              :  :
 *  :  :                 \                      \             :  :
 *  :  :                  \                      \            :  :
 *  :  :                   ring_empty---->WAIT_DATA           :  :
 *  :  :                                                      :  :
 *  :  :......................................................:  :
 *  :............................................................:
 *
 * For the full state machine view, see `The VF state machine`_.
 */

static void pf_exit_vf_restore_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WIP)) {
                xe_gt_sriov_pf_migration_ring_free(gt, vfid);

                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_PROCESS_DATA);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WAIT_DATA);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_DATA_DONE);
        }
}

static void pf_enter_vf_restored(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORED))
                pf_enter_vf_state_machine_bug(gt, vfid);

        xe_gt_sriov_dbg(gt, "VF%u restored!\n", vfid);

        pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED);
        pf_exit_vf_mismatch(gt, vfid);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_restore_failed(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_FAILED))
                pf_enter_vf_state_machine_bug(gt, vfid);

        wake_up_all(xe_sriov_pf_migration_waitqueue(gt_to_xe(gt), vfid));

        pf_exit_vf_wip(gt, vfid);
}

static int pf_handle_vf_restore_data(struct xe_gt *gt, unsigned int vfid)
{
        struct xe_sriov_packet *data = xe_gt_sriov_pf_migration_restore_consume(gt, vfid);
        int ret = 0;

        switch (data->hdr.type) {
        case XE_SRIOV_PACKET_TYPE_GGTT:
                ret = xe_gt_sriov_pf_migration_ggtt_restore(gt, vfid, data);
                break;
        case XE_SRIOV_PACKET_TYPE_MMIO:
                ret = xe_gt_sriov_pf_migration_mmio_restore(gt, vfid, data);
                break;
        case XE_SRIOV_PACKET_TYPE_GUC:
                ret = xe_gt_sriov_pf_migration_guc_restore(gt, vfid, data);
                break;
        case XE_SRIOV_PACKET_TYPE_VRAM:
                ret = xe_gt_sriov_pf_migration_vram_restore(gt, vfid, data);
                break;
        default:
                xe_gt_sriov_notice(gt, "Skipping VF%u unknown data type: %d\n",
                                   vfid, data->hdr.type);
                break;
        }

        xe_sriov_packet_free(data);

        return ret;
}

static bool pf_handle_vf_restore(struct xe_gt *gt, unsigned int vfid)
{
        int ret;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_PROCESS_DATA))
                return false;

        if (xe_gt_sriov_pf_migration_ring_empty(gt, vfid)) {
                if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_DATA_DONE))
                        pf_enter_vf_restored(gt, vfid);
                else
                        pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WAIT_DATA);

                return true;
        }

        ret = pf_handle_vf_restore_data(gt, vfid);
        if (ret)
                pf_enter_vf_restore_failed(gt, vfid);
        else
                pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_PROCESS_DATA);

        return true;
}

static void pf_exit_vf_restore_wait_data(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WAIT_DATA))
                return;

        pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_PROCESS_DATA);
        pf_queue_vf(gt, vfid);
}

static bool pf_enter_vf_restore_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WIP)) {
                pf_enter_vf_wip(gt, vfid);
                pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_PROCESS_DATA);
                pf_queue_vf(gt, vfid);
                return true;
        }

        return false;
}

/**
 * xe_gt_sriov_pf_control_check_restore_failed() - Check if restore processing has failed.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: true if restore processing failed, false otherwise.
 */
bool xe_gt_sriov_pf_control_check_restore_failed(struct xe_gt *gt, unsigned int vfid)
{
        return pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_FAILED);
}

/**
 * xe_gt_sriov_pf_control_restore_data_done() - Indicate the end of VF migration data stream.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_restore_data_done(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_DATA_DONE)) {
                pf_enter_vf_state_machine_bug(gt, vfid);
                return -EIO;
        }

        return xe_gt_sriov_pf_control_process_restore_data(gt, vfid);
}

/**
 * xe_gt_sriov_pf_control_process_restore_data() - Queue VF restore migration data processing.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_process_restore_data(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_expect_vf_not_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_FAILED)) {
                xe_gt_sriov_pf_migration_ring_free(gt, vfid);
                return -EIO;
        }

        pf_exit_vf_restore_wait_data(gt, vfid);

        return 0;
}

/**
 * xe_gt_sriov_pf_control_trigger restore_vf() - Start an SR-IOV VF migration data restore sequence.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_trigger_restore_vf(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOPPED)) {
                xe_gt_sriov_dbg(gt, "VF%u is stopped!\n", vfid);
                return -EPERM;
        }

        if (!pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED)) {
                xe_gt_sriov_dbg(gt, "VF%u is not paused!\n", vfid);
                return -EPERM;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WIP)) {
                xe_gt_sriov_dbg(gt, "VF%u save is in progress!\n", vfid);
                return -EBUSY;
        }

        if (!pf_enter_vf_restore_wip(gt, vfid)) {
                xe_gt_sriov_dbg(gt, "VF%u restore already in progress!\n", vfid);
                return -EALREADY;
        }

        return 0;
}

static int pf_wait_vf_restore_done(struct xe_gt *gt, unsigned int vfid)
{
        unsigned long timeout = pf_get_default_timeout(XE_GT_SRIOV_STATE_RESTORE_WIP);
        int err;

        err = pf_wait_vf_wip_done(gt, vfid, timeout);
        if (err) {
                xe_gt_sriov_notice(gt, "VF%u RESTORE didn't finish in %u ms (%pe)\n",
                                   vfid, jiffies_to_msecs(timeout), ERR_PTR(err));
                return err;
        }

        if (!pf_expect_vf_not_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_FAILED))
                return -EIO;

        return 0;
}

/**
 * xe_gt_sriov_pf_control_finish_restore_vf() - Complete a VF migration data restore sequence.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_finish_restore_vf(struct xe_gt *gt, unsigned int vfid)
{
        int ret;

        ret = pf_wait_vf_restore_done(gt, vfid);
        if (ret)
                return ret;

        if (!pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORED)) {
                pf_enter_vf_mismatch(gt, vfid);
                return -EIO;
        }

        pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED);

        return 0;
}

/**
 * DOC: The VF STOP state machine
 *
 * The VF STOP state machine looks like::
 *
 *       (READY,PAUSED,RESUMED)<-------<--------------------o
 *          |                                                \
 *         stop                                               \
 *          |                                                  \
 *      ....V..............................STOP_WIP......       \
 *      :    \                                          :        o
 *      :     \   o----<----busy                        :        |
 *      :      \ /            /                         :        |
 *      :       STOP_SEND_STOP--------failed--->--------o--->(STOP_FAILED)
 *      :       /             \                         :        |
 *      :    acked             rejected-------->--------o--->(MISMATCH)
 *      :     /                                         :
 *      :....o..............o...............o...........:
 *           |              |               |
 *        completed        flr            restart
 *           |              |               |
 *           V         .....V.....          V
 *       (STOPPED)     : FLR_WIP :       (READY)
 *                     :.........:
 *
 * For the full state machine view, see `The VF state machine`_.
 */

static void pf_exit_vf_stop_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_WIP))
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_SEND_STOP);
}

static void pf_enter_vf_stopped(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOPPED))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESUMED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVED);
        pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORED);
        pf_exit_vf_mismatch(gt, vfid);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_stop_completed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_stopped(gt, vfid);
}

static void pf_enter_vf_stop_failed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_FAILED);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_stop_rejected(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_mismatch(gt, vfid);
        pf_enter_vf_stop_failed(gt, vfid);
}

static void pf_enter_vf_stop_send_stop(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_SEND_STOP))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static bool pf_exit_vf_stop_send_stop(struct xe_gt *gt, unsigned int vfid)
{
        int err;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_SEND_STOP))
                return false;

        err = pf_send_vf_stop(gt, vfid);
        if (err == -EBUSY)
                pf_enter_vf_stop_send_stop(gt, vfid);
        else if (err == -EIO)
                pf_enter_vf_stop_rejected(gt, vfid);
        else if (err)
                pf_enter_vf_stop_failed(gt, vfid);
        else
                pf_enter_vf_stop_completed(gt, vfid);
        return true;
}

static bool pf_enter_vf_stop_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_WIP)) {
                pf_enter_vf_wip(gt, vfid);
                pf_enter_vf_stop_send_stop(gt, vfid);
                return true;
        }
        return false;
}

/**
 * xe_gt_sriov_pf_control_stop_vf - Stop a VF.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_stop_vf(struct xe_gt *gt, unsigned int vfid)
{
        unsigned long timeout = pf_get_default_timeout(XE_GT_SRIOV_STATE_STOP_WIP);
        int err;

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOPPED)) {
                xe_gt_sriov_dbg(gt, "VF%u was already stopped!\n", vfid);
                return -ESTALE;
        }

        if (!pf_enter_vf_stop_wip(gt, vfid)) {
                xe_gt_sriov_dbg(gt, "VF%u stop already in progress!\n", vfid);
                return -EALREADY;
        }

        err = pf_wait_vf_wip_done(gt, vfid, timeout);
        if (err)
                return err;

        if (pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOPPED)) {
                xe_gt_sriov_dbg(gt, "VF%u stopped!\n", vfid);
                return 0;
        }

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_STOP_FAILED)) {
                xe_gt_sriov_dbg(gt, "VF%u stop failed!\n", vfid);
                return -EIO;
        }

        xe_gt_sriov_dbg(gt, "VF%u stop was canceled!\n", vfid);
        return -ECANCELED;
}

/**
 * DOC: The VF FLR state machine
 *
 * The VF FLR state machine looks like::
 *
 *       (READY,PAUSED,STOPPED)<------------<--------------o
 *          |                                               \
 *         flr                                               \
 *          |                                                 \
 *      ....V..........................FLR_WIP...........      \
 *      :    \                                          :       \
 *      :     \   o----<----busy                        :        |
 *      :      \ /            /                         :        |
 *      :       FLR_SEND_START---failed----->-----------o--->(FLR_FAILED)<---o
 *      :        |            \                         :        |           |
 *      :      acked           rejected----->-----------o--->(MISMATCH)      |
 *      :        |                                      :        ^           |
 *      :        v                                      :        |           |
 *      :       FLR_WAIT_GUC                            :        |           |
 *      :        |                                      :        |           |
 *      :       done                                    :        |           |
 *      :        |                                      :        |           |
 *      :        v                                      :        |           |
 *      :       FLR_GUC_DONE                            :        |           |
 *      :        |                                      :        |           |
 *      :        | o--<--sync                           :        |           |
 *      :        |/        /                            :        |           |
 *      :       FLR_SYNC--o                             :        |           |
 *      :        |                                      :        |           |
 *      :       FLR_RESET_CONFIG---failed--->-----------o--------+-----------o
 *      :        |                                      :        |           |
 *      :       FLR_RESET_DATA                          :        |           |
 *      :        |                                      :        |           |
 *      :       FLR_RESET_MMIO                          :        |           |
 *      :        |                                      :        |           |
 *      :        | o----<----busy                       :        |           |
 *      :        |/            /                        :        |           |
 *      :       FLR_SEND_FINISH----failed--->-----------o--------+-----------o
 *      :       /             \                         :        |
 *      :     acked            rejected----->-----------o--------o
 *      :     /                                         :
 *      :....o..............................o...........:
 *           |                              |
 *        completed                       restart
 *           |                             /
 *           V                            /
 *        (READY)<----------<------------o
 *
 * For the full state machine view, see `The VF state machine`_.
 */

static void pf_enter_vf_flr_send_start(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_START))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static void pf_enter_vf_flr_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WIP)) {
                xe_gt_sriov_dbg(gt, "VF%u FLR is already in progress\n", vfid);
                return;
        }

        pf_enter_vf_wip(gt, vfid);
        pf_enter_vf_flr_send_start(gt, vfid);
}

static void pf_exit_vf_flr_wip(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WIP)) {
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_FINISH);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_MMIO);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_DATA);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_CONFIG);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_GUC_DONE);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WAIT_GUC);
                pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_START);

                xe_sriov_pf_control_sync_flr(gt_to_xe(gt), vfid);
        }
}

static void pf_enter_vf_flr_completed(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_ready(gt, vfid);
}

static void pf_enter_vf_flr_failed(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_FAILED))
                xe_gt_sriov_notice(gt, "VF%u FLR failed!\n", vfid);
        pf_exit_vf_wip(gt, vfid);
}

static void pf_enter_vf_flr_rejected(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_mismatch(gt, vfid);
        pf_enter_vf_flr_failed(gt, vfid);
}

static void pf_enter_vf_flr_send_finish(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_FINISH))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static bool pf_exit_vf_flr_send_finish(struct xe_gt *gt, unsigned int vfid)
{
        int err;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_FINISH))
                return false;

        err = pf_send_vf_flr_finish(gt, vfid);
        if (err == -EBUSY)
                pf_enter_vf_flr_send_finish(gt, vfid);
        else if (err == -EIO)
                pf_enter_vf_flr_rejected(gt, vfid);
        else if (err)
                pf_enter_vf_flr_failed(gt, vfid);
        else
                pf_enter_vf_flr_completed(gt, vfid);
        return true;
}

static void pf_enter_vf_flr_reset_mmio(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_MMIO))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static bool pf_exit_vf_flr_reset_mmio(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_MMIO))
                return false;

        xe_gt_sriov_pf_sanitize_hw(gt, vfid);

        pf_enter_vf_flr_send_finish(gt, vfid);
        return true;
}

static void pf_enter_vf_flr_reset_data(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_DATA))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static bool pf_exit_vf_flr_reset_data(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_DATA))
                return false;

        if (xe_tile_is_root(gt->tile) && xe_gt_is_main_type(gt))
                xe_sriov_pf_service_reset_vf(gt_to_xe(gt), vfid);

        xe_gt_sriov_pf_monitor_flr(gt, vfid);

        pf_enter_vf_flr_reset_mmio(gt, vfid);
        return true;
}

static void pf_enter_vf_flr_reset_config(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_CONFIG))
                pf_enter_vf_state_machine_bug(gt, vfid);

        pf_queue_vf(gt, vfid);
}

static bool pf_exit_vf_flr_reset_config(struct xe_gt *gt, unsigned int vfid)
{
        unsigned long timeout = pf_get_default_timeout(XE_GT_SRIOV_STATE_FLR_RESET_CONFIG);
        int err;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_CONFIG))
                return false;

        err = xe_gt_sriov_pf_config_sanitize(gt, vfid, timeout);
        if (err)
                pf_enter_vf_flr_failed(gt, vfid);
        else
                pf_enter_vf_flr_reset_data(gt, vfid);
        return true;
}

static void pf_enter_vf_flr_wait_guc(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WAIT_GUC))
                pf_enter_vf_state_machine_bug(gt, vfid);
}

static bool pf_exit_vf_flr_wait_guc(struct xe_gt *gt, unsigned int vfid)
{
        return pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WAIT_GUC);
}

static bool pf_exit_vf_flr_send_start(struct xe_gt *gt, unsigned int vfid)
{
        int err;

        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_START))
                return false;

        /* GuC may actually send a FLR_DONE before we get a RESPONSE */
        pf_enter_vf_flr_wait_guc(gt, vfid);

        err = pf_send_vf_flr_start(gt, vfid);
        if (err) {
                /* send failed, so we shouldn't expect FLR_DONE from GuC */
                pf_exit_vf_flr_wait_guc(gt, vfid);

                if (err == -EBUSY)
                        pf_enter_vf_flr_send_start(gt, vfid);
                else if (err == -EIO)
                        pf_enter_vf_flr_rejected(gt, vfid);
                else
                        pf_enter_vf_flr_failed(gt, vfid);
        } else {
                /*
                 * we have already moved to WAIT_GUC, maybe even to GUC_DONE
                 * but since GuC didn't complain, we may clear MISMATCH
                 */
                pf_exit_vf_mismatch(gt, vfid);
        }

        return true;
}

static bool pf_exit_vf_flr_sync(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SYNC))
                return false;

        pf_enter_vf_flr_reset_config(gt, vfid);
        return true;
}

static void pf_enter_vf_flr_sync(struct xe_gt *gt, unsigned int vfid)
{
        int ret;

        if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SYNC))
                pf_enter_vf_state_machine_bug(gt, vfid);

        ret = xe_sriov_pf_control_sync_flr(gt_to_xe(gt), vfid);
        if (ret < 0) {
                xe_gt_sriov_dbg_verbose(gt, "FLR checkpoint %pe\n", ERR_PTR(ret));
                pf_expect_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SYNC);
        } else {
                xe_gt_sriov_dbg_verbose(gt, "FLR checkpoint pass\n");
                pf_expect_vf_not_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SYNC);
        }
}

static bool pf_exit_vf_flr_guc_done(struct xe_gt *gt, unsigned int vfid)
{
        if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_GUC_DONE))
                return false;

        pf_enter_vf_flr_sync(gt, vfid);
        return true;
}

static void pf_enter_vf_flr_guc_done(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_GUC_DONE))
                pf_queue_vf(gt, vfid);
}

/**
 * xe_gt_sriov_pf_control_trigger_flr - Start a VF FLR sequence.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_trigger_flr(struct xe_gt *gt, unsigned int vfid)
{
        pf_enter_vf_flr_wip(gt, vfid);

        return 0;
}

/**
 * xe_gt_sriov_pf_control_sync_flr() - Synchronize on the VF FLR checkpoint.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 * @sync: if true it will allow to exit the checkpoint
 *
 * Return: non-zero if FLR checkpoint has been reached, zero if the is no FLR
 *         in progress, or a negative error code on the FLR busy or failed.
 */
int xe_gt_sriov_pf_control_sync_flr(struct xe_gt *gt, unsigned int vfid, bool sync)
{
        if (sync && pf_exit_vf_flr_sync(gt, vfid))
                return 1;
        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SYNC))
                return 1;
        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WIP))
                return -EBUSY;
        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_FAILED))
                return -EIO;
        return 0;
}

/**
 * xe_gt_sriov_pf_control_wait_flr() - Wait for a VF FLR to complete.
 * @gt: the &xe_gt
 * @vfid: the VF identifier
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_wait_flr(struct xe_gt *gt, unsigned int vfid)
{
        unsigned long timeout = pf_get_default_timeout(XE_GT_SRIOV_STATE_FLR_WIP);
        int err;

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_FAILED))
                return -EIO;

        if (!pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WIP))
                return 0;

        err = pf_wait_vf_wip_done(gt, vfid, timeout);
        if (err) {
                xe_gt_sriov_notice(gt, "VF%u FLR didn't finish in %u ms (%pe)\n",
                                   vfid, jiffies_to_msecs(timeout), ERR_PTR(err));
                return err;
        }

        if (!pf_expect_vf_not_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_FAILED))
                return -EIO;

        return 0;
}

/**
 * DOC: The VF FLR Flow with GuC
 *
 * The VF FLR flow includes several steps::
 *
 *               PF                        GUC             PCI
 *      ========================================================
 *               |                          |               |
 *      (1)      |                         [ ] <----- FLR --|
 *               |                         [ ]              :
 *      (2)     [ ] <-------- NOTIFY FLR --[ ]
 *              [ ]                         |
 *      (3)     [ ]                         |
 *              [ ]                         |
 *              [ ]-- START FLR ---------> [ ]
 *               |                         [ ]
 *      (4)      |                         [ ]
 *               |                         [ ]
 *              [ ] <--------- FLR DONE -- [ ]
 *              [ ]                         |
 *      (5)     [ ]                         |
 *              [ ]                         |
 *              [ ]-- FINISH FLR --------> [ ]
 *               |                          |
 *
 * * Step 1: PCI HW generates interrupt to the GuC about VF FLR
 * * Step 2: GuC FW sends G2H notification to the PF about VF FLR
 * * Step 2a: on some platforms G2H is only received from root GuC
 * * Step 3: PF sends H2G request to the GuC to start VF FLR sequence
 * * Step 3a: on some platforms PF must send H2G to all other GuCs
 * * Step 4: GuC FW performs VF FLR cleanups and notifies the PF when done
 * * Step 5: PF performs VF FLR cleanups and notifies the GuC FW when finished
 */

static bool needs_dispatch_flr(struct xe_device *xe)
{
        return xe->info.platform == XE_PVC;
}

static void pf_handle_vf_flr(struct xe_gt *gt, u32 vfid)
{
        struct xe_device *xe = gt_to_xe(gt);
        struct xe_gt *gtit;
        unsigned int gtid;

        xe_gt_sriov_info(gt, "VF%u FLR\n", vfid);

        if (needs_dispatch_flr(xe)) {
                for_each_gt(gtit, xe, gtid)
                        pf_enter_vf_flr_wip(gtit, vfid);
        } else {
                pf_enter_vf_flr_wip(gt, vfid);
        }
}

static void pf_handle_vf_flr_done(struct xe_gt *gt, u32 vfid)
{
        if (!pf_exit_vf_flr_wait_guc(gt, vfid)) {
                xe_gt_sriov_dbg(gt, "Received out of order 'VF%u FLR done'\n", vfid);
                pf_enter_vf_mismatch(gt, vfid);
                return;
        }

        pf_enter_vf_flr_guc_done(gt, vfid);
}

static void pf_handle_vf_pause_done(struct xe_gt *gt, u32 vfid)
{
        if (!pf_exit_pause_wait_guc(gt, vfid)) {
                xe_gt_sriov_dbg(gt, "Received out of order 'VF%u PAUSE done'\n", vfid);
                pf_enter_vf_mismatch(gt, vfid);
                return;
        }

        pf_enter_vf_pause_guc_done(gt, vfid);
}

static int pf_handle_vf_event(struct xe_gt *gt, u32 vfid, u32 eventid)
{
        xe_gt_sriov_dbg_verbose(gt, "received VF%u event %#x\n", vfid, eventid);

        if (vfid > xe_gt_sriov_pf_get_totalvfs(gt))
                return -EPROTO;

        switch (eventid) {
        case GUC_PF_NOTIFY_VF_FLR:
                pf_handle_vf_flr(gt, vfid);
                break;
        case GUC_PF_NOTIFY_VF_FLR_DONE:
                pf_handle_vf_flr_done(gt, vfid);
                break;
        case GUC_PF_NOTIFY_VF_PAUSE_DONE:
                pf_handle_vf_pause_done(gt, vfid);
                break;
        case GUC_PF_NOTIFY_VF_FIXUP_DONE:
                break;
        default:
                return -ENOPKG;
        }
        return 0;
}

static int pf_handle_pf_event(struct xe_gt *gt, u32 eventid)
{
        switch (eventid) {
        case GUC_PF_NOTIFY_VF_ENABLE:
                xe_gt_sriov_dbg_verbose(gt, "VFs %s/%s\n",
                                        str_enabled_disabled(true),
                                        str_enabled_disabled(false));
                break;
        default:
                return -ENOPKG;
        }
        return 0;
}

/**
 * xe_gt_sriov_pf_control_process_guc2pf - Handle VF state notification from GuC.
 * @gt: the &xe_gt
 * @msg: the G2H message
 * @len: the length of the G2H message
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_process_guc2pf(struct xe_gt *gt, const u32 *msg, u32 len)
{
        u32 vfid;
        u32 eventid;

        xe_gt_assert(gt, len);
        xe_gt_assert(gt, FIELD_GET(GUC_HXG_MSG_0_ORIGIN, msg[0]) == GUC_HXG_ORIGIN_GUC);
        xe_gt_assert(gt, FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0]) == GUC_HXG_TYPE_EVENT);
        xe_gt_assert(gt, FIELD_GET(GUC_HXG_EVENT_MSG_0_ACTION, msg[0]) ==
                     GUC_ACTION_GUC2PF_VF_STATE_NOTIFY);

        if (unlikely(!xe_device_is_sriov_pf(gt_to_xe(gt))))
                return -EPROTO;

        if (unlikely(FIELD_GET(GUC2PF_VF_STATE_NOTIFY_EVENT_MSG_0_MBZ, msg[0])))
                return -EPFNOSUPPORT;

        if (unlikely(len != GUC2PF_VF_STATE_NOTIFY_EVENT_MSG_LEN))
                return -EPROTO;

        vfid = FIELD_GET(GUC2PF_VF_STATE_NOTIFY_EVENT_MSG_1_VFID, msg[1]);
        eventid = FIELD_GET(GUC2PF_VF_STATE_NOTIFY_EVENT_MSG_2_EVENT, msg[2]);

        return vfid ? pf_handle_vf_event(gt, vfid, eventid) : pf_handle_pf_event(gt, eventid);
}

static bool pf_process_vf_state_machine(struct xe_gt *gt, unsigned int vfid)
{
        if (pf_exit_vf_flr_send_start(gt, vfid))
                return true;

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WAIT_GUC)) {
                xe_gt_sriov_dbg_verbose(gt, "VF%u in %s\n", vfid,
                                        control_bit_to_string(XE_GT_SRIOV_STATE_FLR_WAIT_GUC));
                return false;
        }

        if (pf_exit_vf_flr_guc_done(gt, vfid))
                return true;

        if (pf_exit_vf_flr_reset_config(gt, vfid))
                return true;

        if (pf_exit_vf_flr_reset_data(gt, vfid))
                return true;

        if (pf_exit_vf_flr_reset_mmio(gt, vfid))
                return true;

        if (pf_exit_vf_flr_send_finish(gt, vfid))
                return true;

        if (pf_exit_vf_stop_send_stop(gt, vfid))
                return true;

        if (pf_exit_vf_pause_send_pause(gt, vfid))
                return true;

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_PAUSE_WAIT_GUC)) {
                xe_gt_sriov_dbg_verbose(gt, "VF%u in %s\n", vfid,
                                        control_bit_to_string(XE_GT_SRIOV_STATE_PAUSE_WAIT_GUC));
                return true;
        }

        if (pf_exit_vf_pause_guc_done(gt, vfid))
                return true;

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WAIT_DATA)) {
                xe_gt_sriov_dbg_verbose(gt, "VF%u in %s\n", vfid,
                                        control_bit_to_string(XE_GT_SRIOV_STATE_SAVE_WAIT_DATA));
                return false;
        }

        if (pf_handle_vf_save(gt, vfid))
                return true;

        if (pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WAIT_DATA)) {
                xe_gt_sriov_dbg_verbose(gt, "VF%u in %s\n", vfid,
                                        control_bit_to_string(XE_GT_SRIOV_STATE_RESTORE_WAIT_DATA));
                return false;
        }

        if (pf_handle_vf_restore(gt, vfid))
                return true;

        if (pf_exit_vf_resume_send_resume(gt, vfid))
                return true;

        return false;
}

static unsigned int pf_control_state_index(struct xe_gt *gt,
                                           struct xe_gt_sriov_control_state *cs)
{
        return container_of(cs, struct xe_gt_sriov_metadata, control) - gt->sriov.pf.vfs;
}

static void pf_worker_find_work(struct xe_gt *gt)
{
        struct xe_gt_sriov_pf_control *pfc = &gt->sriov.pf.control;
        struct xe_gt_sriov_control_state *cs;
        unsigned int vfid;
        bool empty;
        bool more;

        spin_lock(&pfc->lock);
        cs = list_first_entry_or_null(&pfc->list, struct xe_gt_sriov_control_state, link);
        if (cs)
                list_del_init(&cs->link);
        empty = list_empty(&pfc->list);
        spin_unlock(&pfc->lock);

        if (!cs)
                return;

        /* VF metadata structures are indexed by the VFID */
        vfid = pf_control_state_index(gt, cs);
        xe_gt_assert(gt, vfid <= xe_gt_sriov_pf_get_totalvfs(gt));

        more = pf_process_vf_state_machine(gt, vfid);
        if (more)
                pf_queue_vf(gt, vfid);
        else if (!empty)
                pf_queue_control_worker(gt);
}

static void control_worker_func(struct work_struct *w)
{
        struct xe_gt *gt = container_of(w, struct xe_gt, sriov.pf.control.worker);

        xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
        pf_worker_find_work(gt);
}

static void pf_stop_worker(struct xe_gt *gt)
{
        xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
        cancel_work_sync(&gt->sriov.pf.control.worker);
}

static void control_fini_action(struct drm_device *dev, void *data)
{
        struct xe_gt *gt = data;

        pf_stop_worker(gt);
}

/**
 * xe_gt_sriov_pf_control_init() - Initialize PF's control data.
 * @gt: the &xe_gt
 *
 * This function is for PF only.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_gt_sriov_pf_control_init(struct xe_gt *gt)
{
        struct xe_device *xe = gt_to_xe(gt);
        unsigned int n, totalvfs;

        xe_gt_assert(gt, IS_SRIOV_PF(xe));

        totalvfs = xe_sriov_pf_get_totalvfs(xe);
        for (n = 0; n <= totalvfs; n++) {
                struct xe_gt_sriov_control_state *cs = pf_pick_vf_control(gt, n);

                init_completion(&cs->done);
                INIT_LIST_HEAD(&cs->link);
        }

        spin_lock_init(&gt->sriov.pf.control.lock);
        INIT_LIST_HEAD(&gt->sriov.pf.control.list);
        INIT_WORK(&gt->sriov.pf.control.worker, control_worker_func);

        return drmm_add_action_or_reset(&xe->drm, control_fini_action, gt);
}

/**
 * xe_gt_sriov_pf_control_restart() - Restart SR-IOV control data after a GT reset.
 * @gt: the &xe_gt
 *
 * Any per-VF status maintained by the PF or any ongoing VF control activity
 * performed by the PF must be reset or cancelled when the GT is reset.
 *
 * This function is for PF only.
 */
void xe_gt_sriov_pf_control_restart(struct xe_gt *gt)
{
        struct xe_device *xe = gt_to_xe(gt);
        unsigned int n, totalvfs;

        xe_gt_assert(gt, IS_SRIOV_PF(xe));

        pf_stop_worker(gt);

        totalvfs = xe_sriov_pf_get_totalvfs(xe);
        for (n = 1; n <= totalvfs; n++)
                pf_enter_vf_ready(gt, n);
}