/*
 * Copyright 2021 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
#include "runl.h"
#include "cgrp.h"
#include "chan.h"
#include "chid.h"
#include "priv.h"
#include "runq.h"

#include <core/gpuobj.h>
#include <subdev/timer.h>
#include <subdev/top.h>

static struct nvkm_cgrp *
nvkm_engn_cgrp_get(struct nvkm_engn *engn, unsigned long *pirqflags)
{
        struct nvkm_cgrp *cgrp = NULL;
        struct nvkm_chan *chan;
        bool cgid;
        int id;

        id = engn->func->cxid(engn, &cgid);
        if (id < 0)
                return NULL;

        if (!cgid) {
                chan = nvkm_runl_chan_get_chid(engn->runl, id, pirqflags);
                if (chan)
                        cgrp = chan->cgrp;
        } else {
                cgrp = nvkm_runl_cgrp_get_cgid(engn->runl, id, pirqflags);
        }

        WARN_ON(!cgrp);
        return cgrp;
}

static void
nvkm_runl_rc(struct nvkm_runl *runl)
{
        struct nvkm_fifo *fifo = runl->fifo;
        struct nvkm_cgrp *cgrp, *gtmp;
        struct nvkm_chan *chan, *ctmp;
        struct nvkm_engn *engn;
        unsigned long flags;
        int rc, state, i;
        bool reset;

        /* Runlist is blocked before scheduling recovery - fetch count. */
        BUG_ON(!mutex_is_locked(&runl->mutex));
        rc = atomic_xchg(&runl->rc_pending, 0);
        if (!rc)
                return;

        /* Look for channel groups flagged for RC. */
        nvkm_runl_foreach_cgrp_safe(cgrp, gtmp, runl) {
                state = atomic_cmpxchg(&cgrp->rc, NVKM_CGRP_RC_PENDING, NVKM_CGRP_RC_RUNNING);
                if (state == NVKM_CGRP_RC_PENDING) {
                        /* Disable all channels in them, and remove from runlist. */
                        nvkm_cgrp_foreach_chan_safe(chan, ctmp, cgrp) {
                                nvkm_chan_error(chan, false);
                                nvkm_chan_remove_locked(chan);
                        }
                }
        }

        /* On GPUs with runlist preempt, wait for PBDMA(s) servicing runlist to go idle. */
        if (runl->func->preempt) {
                for (i = 0; i < runl->runq_nr; i++) {
                        struct nvkm_runq *runq = runl->runq[i];

                        if (runq) {
                                nvkm_msec(fifo->engine.subdev.device, 2000,
                                        if (runq->func->idle(runq))
                                                break;
                                );
                        }
                }
        }

        /* Look for engines that are still on flagged channel groups - reset them. */
        nvkm_runl_foreach_engn_cond(engn, runl, engn->func->cxid) {
                cgrp = nvkm_engn_cgrp_get(engn, &flags);
                if (!cgrp) {
                        ENGN_DEBUG(engn, "cxid not valid");
                        continue;
                }

                reset = atomic_read(&cgrp->rc) == NVKM_CGRP_RC_RUNNING;
                nvkm_cgrp_put(&cgrp, flags);
                if (!reset) {
                        ENGN_DEBUG(engn, "cxid not in recovery");
                        continue;
                }

                ENGN_DEBUG(engn, "resetting...");
                /*TODO: can we do something less of a potential catastrophe on failure? */
                WARN_ON(nvkm_engine_reset(engn->engine));
        }

        /* Submit runlist update, and clear any remaining exception state. */
        runl->func->update(runl);
        if (runl->func->fault_clear)
                runl->func->fault_clear(runl);

        /* Unblock runlist processing. */
        while (rc--)
                nvkm_runl_allow(runl);
        runl->func->wait(runl);
}

static void
nvkm_runl_rc_runl(struct nvkm_runl *runl)
{
        RUNL_ERROR(runl, "rc scheduled");

        nvkm_runl_block(runl);
        if (runl->func->preempt)
                runl->func->preempt(runl);

        atomic_inc(&runl->rc_pending);
        schedule_work(&runl->work);
}

void
nvkm_runl_rc_cgrp(struct nvkm_cgrp *cgrp)
{
        if (atomic_cmpxchg(&cgrp->rc, NVKM_CGRP_RC_NONE, NVKM_CGRP_RC_PENDING) != NVKM_CGRP_RC_NONE)
                return;

        CGRP_ERROR(cgrp, "rc scheduled");
        nvkm_runl_rc_runl(cgrp->runl);
}

void
nvkm_runl_rc_engn(struct nvkm_runl *runl, struct nvkm_engn *engn)
{
        struct nvkm_cgrp *cgrp;
        unsigned long flags;

        /* Lookup channel group currently on engine. */
        cgrp = nvkm_engn_cgrp_get(engn, &flags);
        if (!cgrp) {
                ENGN_DEBUG(engn, "rc skipped, not on channel");
                return;
        }

        nvkm_runl_rc_cgrp(cgrp);
        nvkm_cgrp_put(&cgrp, flags);
}

static void
nvkm_runl_work(struct work_struct *work)
{
        struct nvkm_runl *runl = container_of(work, typeof(*runl), work);

        mutex_lock(&runl->mutex);
        nvkm_runl_rc(runl);
        mutex_unlock(&runl->mutex);

}

struct nvkm_chan *
nvkm_runl_chan_get_inst(struct nvkm_runl *runl, u64 inst, unsigned long *pirqflags)
{
        struct nvkm_chid *chid = runl->chid;
        struct nvkm_chan *chan;
        unsigned long flags;
        int id;

        spin_lock_irqsave(&chid->lock, flags);
        for_each_set_bit(id, chid->used, chid->nr) {
                chan = chid->data[id];
                if (likely(chan)) {
                        if (chan->inst->addr == inst) {
                                spin_lock(&chan->cgrp->lock);
                                *pirqflags = flags;
                                spin_unlock(&chid->lock);
                                return chan;
                        }
                }
        }
        spin_unlock_irqrestore(&chid->lock, flags);
        return NULL;
}

struct nvkm_chan *
nvkm_runl_chan_get_chid(struct nvkm_runl *runl, int id, unsigned long *pirqflags)
{
        struct nvkm_chid *chid = runl->chid;
        struct nvkm_chan *chan;
        unsigned long flags;

        spin_lock_irqsave(&chid->lock, flags);
        if (!WARN_ON(id >= chid->nr)) {
                chan = chid->data[id];
                if (likely(chan)) {
                        spin_lock(&chan->cgrp->lock);
                        *pirqflags = flags;
                        spin_unlock(&chid->lock);
                        return chan;
                }
        }
        spin_unlock_irqrestore(&chid->lock, flags);
        return NULL;
}

struct nvkm_cgrp *
nvkm_runl_cgrp_get_cgid(struct nvkm_runl *runl, int id, unsigned long *pirqflags)
{
        struct nvkm_chid *cgid = runl->cgid;
        struct nvkm_cgrp *cgrp;
        unsigned long flags;

        spin_lock_irqsave(&cgid->lock, flags);
        if (!WARN_ON(id >= cgid->nr)) {
                cgrp = cgid->data[id];
                if (likely(cgrp)) {
                        spin_lock(&cgrp->lock);
                        *pirqflags = flags;
                        spin_unlock(&cgid->lock);
                        return cgrp;
                }
        }
        spin_unlock_irqrestore(&cgid->lock, flags);
        return NULL;
}

int
nvkm_runl_preempt_wait(struct nvkm_runl *runl)
{
        return nvkm_msec(runl->fifo->engine.subdev.device, runl->fifo->timeout.chan_msec,
                if (!runl->func->preempt_pending(runl))
                        break;

                nvkm_runl_rc(runl);
                usleep_range(1, 2);
        ) < 0 ? -ETIMEDOUT : 0;
}

bool
nvkm_runl_update_pending(struct nvkm_runl *runl)
{
        if (!runl->func->pending(runl))
                return false;

        nvkm_runl_rc(runl);
        return true;
}

void
nvkm_runl_update_locked(struct nvkm_runl *runl, bool wait)
{
        if (atomic_xchg(&runl->changed, 0) && runl->func->update) {
                runl->func->update(runl);
                if (wait)
                        runl->func->wait(runl);
        }
}

void
nvkm_runl_allow(struct nvkm_runl *runl)
{
        struct nvkm_fifo *fifo = runl->fifo;
        unsigned long flags;

        spin_lock_irqsave(&fifo->lock, flags);
        if (!--runl->blocked) {
                RUNL_TRACE(runl, "running");
                runl->func->allow(runl, ~0);
        }
        spin_unlock_irqrestore(&fifo->lock, flags);
}

void
nvkm_runl_block(struct nvkm_runl *runl)
{
        struct nvkm_fifo *fifo = runl->fifo;
        unsigned long flags;

        spin_lock_irqsave(&fifo->lock, flags);
        if (!runl->blocked++) {
                RUNL_TRACE(runl, "stopped");
                runl->func->block(runl, ~0);
        }
        spin_unlock_irqrestore(&fifo->lock, flags);
}

void
nvkm_runl_fini(struct nvkm_runl *runl)
{
        if (runl->func->fini)
                runl->func->fini(runl);

        flush_work(&runl->work);
}

void
nvkm_runl_del(struct nvkm_runl *runl)
{
        struct nvkm_engn *engn, *engt;

        nvkm_memory_unref(&runl->mem);

        list_for_each_entry_safe(engn, engt, &runl->engns, head) {
                list_del(&engn->head);
                kfree(engn);
        }

        nvkm_chid_unref(&runl->chid);
        nvkm_chid_unref(&runl->cgid);

        list_del(&runl->head);
        mutex_destroy(&runl->mutex);
        kfree(runl);
}

struct nvkm_engn *
nvkm_runl_add(struct nvkm_runl *runl, int engi, const struct nvkm_engn_func *func,
              enum nvkm_subdev_type type, int inst)
{
        struct nvkm_fifo *fifo = runl->fifo;
        struct nvkm_device *device = fifo->engine.subdev.device;
        struct nvkm_engine *engine;
        struct nvkm_engn *engn;

        engine = nvkm_device_engine(device, type, inst);
        if (!engine) {
                RUNL_DEBUG(runl, "engn %d.%d[%s] not found", engi, inst, nvkm_subdev_type[type]);
                return NULL;
        }

        if (!(engn = kzalloc_obj(*engn)))
                return NULL;

        engn->func = func;
        engn->runl = runl;
        engn->id = engi;
        engn->engine = engine;
        engn->fault = -1;
        list_add_tail(&engn->head, &runl->engns);

        /* Lookup MMU engine ID for fault handling. */
        if (device->top)
                engn->fault = nvkm_top_fault_id(device, engine->subdev.type, engine->subdev.inst);

        if (engn->fault < 0 && fifo->func->mmu_fault) {
                const struct nvkm_enum *map = fifo->func->mmu_fault->engine;

                while (map->name) {
                        if (map->data2 == engine->subdev.type && map->inst == engine->subdev.inst) {
                                engn->fault = map->value;
                                break;
                        }
                        map++;
                }
        }

        return engn;
}

struct nvkm_runl *
nvkm_runl_get(struct nvkm_fifo *fifo, int runi, u32 addr)
{
        struct nvkm_runl *runl;

        nvkm_runl_foreach(runl, fifo) {
                if ((runi >= 0 && runl->id == runi) || (runi < 0 && runl->addr == addr))
                        return runl;
        }

        return NULL;
}

struct nvkm_runl *
nvkm_runl_new(struct nvkm_fifo *fifo, int runi, u32 addr, int id_nr)
{
        struct nvkm_subdev *subdev = &fifo->engine.subdev;
        struct nvkm_runl *runl;
        int ret;

        if (!(runl = kzalloc_obj(*runl)))
                return ERR_PTR(-ENOMEM);

        runl->func = fifo->func->runl;
        runl->fifo = fifo;
        runl->id = runi;
        runl->addr = addr;
        INIT_LIST_HEAD(&runl->engns);
        INIT_LIST_HEAD(&runl->cgrps);
        atomic_set(&runl->changed, 0);
        mutex_init(&runl->mutex);
        INIT_WORK(&runl->work, nvkm_runl_work);
        atomic_set(&runl->rc_triggered, 0);
        atomic_set(&runl->rc_pending, 0);
        list_add_tail(&runl->head, &fifo->runls);

        if (!fifo->chid) {
                if ((ret = nvkm_chid_new(&nvkm_chan_event, subdev, id_nr, 0, id_nr, &runl->cgid)) ||
                    (ret = nvkm_chid_new(&nvkm_chan_event, subdev, id_nr, 0, id_nr, &runl->chid))) {
                        RUNL_ERROR(runl, "cgid/chid: %d", ret);
                        nvkm_runl_del(runl);
                        return ERR_PTR(ret);
                }
        } else {
                runl->cgid = nvkm_chid_ref(fifo->cgid);
                runl->chid = nvkm_chid_ref(fifo->chid);
        }

        return runl;
}