// SPDX-License-Identifier: GPL-2.0+
/* Copyright (C) 2018 Broadcom */

/**
 * DOC: Broadcom V3D scheduling
 *
 * The shared DRM GPU scheduler is used to coordinate submitting jobs
 * to the hardware.  Each DRM fd (roughly a client process) gets its
 * own scheduler entity, which will process jobs in order.  The GPU
 * scheduler will round-robin between clients to submit the next job.
 *
 * For simplicity, and in order to keep latency low for interactive
 * jobs when bulk background jobs are queued up, we submit a new job
 * to the HW only when it has completed the last one, instead of
 * filling up the CT[01]Q FIFOs with jobs.  Similarly, we use
 * v3d_job_dependency() to manage the dependency between bin and
 * render, instead of having the clients submit jobs using the HW's
 * semaphores to interlock between them.
 */

#include <linux/kthread.h>

#include "v3d_drv.h"
#include "v3d_regs.h"
#include "v3d_trace.h"

static struct v3d_job *
to_v3d_job(struct drm_sched_job *sched_job)
{
        return container_of(sched_job, struct v3d_job, base);
}

static struct v3d_bin_job *
to_bin_job(struct drm_sched_job *sched_job)
{
        return container_of(sched_job, struct v3d_bin_job, base.base);
}

static struct v3d_render_job *
to_render_job(struct drm_sched_job *sched_job)
{
        return container_of(sched_job, struct v3d_render_job, base.base);
}

static struct v3d_tfu_job *
to_tfu_job(struct drm_sched_job *sched_job)
{
        return container_of(sched_job, struct v3d_tfu_job, base.base);
}

static struct v3d_csd_job *
to_csd_job(struct drm_sched_job *sched_job)
{
        return container_of(sched_job, struct v3d_csd_job, base.base);
}

static void
v3d_job_free(struct drm_sched_job *sched_job)
{
        struct v3d_job *job = to_v3d_job(sched_job);

        drm_sched_job_cleanup(sched_job);
        v3d_job_put(job);
}

/**
 * Returns the fences that the job depends on, one by one.
 *
 * If placed in the scheduler's .dependency method, the corresponding
 * .run_job won't be called until all of them have been signaled.
 */
static struct dma_fence *
v3d_job_dependency(struct drm_sched_job *sched_job,
                   struct drm_sched_entity *s_entity)
{
        struct v3d_job *job = to_v3d_job(sched_job);

        /* XXX: Wait on a fence for switching the GMP if necessary,
         * and then do so.
         */

        if (!xa_empty(&job->deps))
                return xa_erase(&job->deps, job->last_dep++);

        return NULL;
}

static struct dma_fence *v3d_bin_job_run(struct drm_sched_job *sched_job)
{
        struct v3d_bin_job *job = to_bin_job(sched_job);
        struct v3d_dev *v3d = job->base.v3d;
        struct drm_device *dev = &v3d->drm;
        struct dma_fence *fence;
        unsigned long irqflags;

        if (unlikely(job->base.base.s_fence->finished.error))
                return NULL;

        /* Lock required around bin_job update vs
         * v3d_overflow_mem_work().
         */
        spin_lock_irqsave(&v3d->job_lock, irqflags);
        v3d->bin_job = job;
        /* Clear out the overflow allocation, so we don't
         * reuse the overflow attached to a previous job.
         */
        V3D_CORE_WRITE(0, V3D_PTB_BPOS, 0);
        spin_unlock_irqrestore(&v3d->job_lock, irqflags);

        v3d_invalidate_caches(v3d);

        fence = v3d_fence_create(v3d, V3D_BIN);
        if (IS_ERR(fence))
                return NULL;

        if (job->base.irq_fence)
                dma_fence_put(job->base.irq_fence);
        job->base.irq_fence = dma_fence_get(fence);

        trace_v3d_submit_cl(dev, false, to_v3d_fence(fence)->seqno,
                            job->start, job->end);

        /* Set the current and end address of the control list.
         * Writing the end register is what starts the job.
         */
        if (job->qma) {
                V3D_CORE_WRITE(0, V3D_CLE_CT0QMA, job->qma);
                V3D_CORE_WRITE(0, V3D_CLE_CT0QMS, job->qms);
        }
        if (job->qts) {
                V3D_CORE_WRITE(0, V3D_CLE_CT0QTS,
                               V3D_CLE_CT0QTS_ENABLE |
                               job->qts);
        }
        V3D_CORE_WRITE(0, V3D_CLE_CT0QBA, job->start);
        V3D_CORE_WRITE(0, V3D_CLE_CT0QEA, job->end);

        return fence;
}

static struct dma_fence *v3d_render_job_run(struct drm_sched_job *sched_job)
{
        struct v3d_render_job *job = to_render_job(sched_job);
        struct v3d_dev *v3d = job->base.v3d;
        struct drm_device *dev = &v3d->drm;
        struct dma_fence *fence;

        if (unlikely(job->base.base.s_fence->finished.error))
                return NULL;

        v3d->render_job = job;

        /* Can we avoid this flush?  We need to be careful of
         * scheduling, though -- imagine job0 rendering to texture and
         * job1 reading, and them being executed as bin0, bin1,
         * render0, render1, so that render1's flush at bin time
         * wasn't enough.
         */
        v3d_invalidate_caches(v3d);

        fence = v3d_fence_create(v3d, V3D_RENDER);
        if (IS_ERR(fence))
                return NULL;

        if (job->base.irq_fence)
                dma_fence_put(job->base.irq_fence);
        job->base.irq_fence = dma_fence_get(fence);

        trace_v3d_submit_cl(dev, true, to_v3d_fence(fence)->seqno,
                            job->start, job->end);

        /* XXX: Set the QCFG */

        /* Set the current and end address of the control list.
         * Writing the end register is what starts the job.
         */
        V3D_CORE_WRITE(0, V3D_CLE_CT1QBA, job->start);
        V3D_CORE_WRITE(0, V3D_CLE_CT1QEA, job->end);

        return fence;
}

static struct dma_fence *
v3d_tfu_job_run(struct drm_sched_job *sched_job)
{
        struct v3d_tfu_job *job = to_tfu_job(sched_job);
        struct v3d_dev *v3d = job->base.v3d;
        struct drm_device *dev = &v3d->drm;
        struct dma_fence *fence;

        fence = v3d_fence_create(v3d, V3D_TFU);
        if (IS_ERR(fence))
                return NULL;

        v3d->tfu_job = job;
        if (job->base.irq_fence)
                dma_fence_put(job->base.irq_fence);
        job->base.irq_fence = dma_fence_get(fence);

        trace_v3d_submit_tfu(dev, to_v3d_fence(fence)->seqno);

        V3D_WRITE(V3D_TFU_IIA, job->args.iia);
        V3D_WRITE(V3D_TFU_IIS, job->args.iis);
        V3D_WRITE(V3D_TFU_ICA, job->args.ica);
        V3D_WRITE(V3D_TFU_IUA, job->args.iua);
        V3D_WRITE(V3D_TFU_IOA, job->args.ioa);
        V3D_WRITE(V3D_TFU_IOS, job->args.ios);
        V3D_WRITE(V3D_TFU_COEF0, job->args.coef[0]);
        if (job->args.coef[0] & V3D_TFU_COEF0_USECOEF) {
                V3D_WRITE(V3D_TFU_COEF1, job->args.coef[1]);
                V3D_WRITE(V3D_TFU_COEF2, job->args.coef[2]);
                V3D_WRITE(V3D_TFU_COEF3, job->args.coef[3]);
        }
        /* ICFG kicks off the job. */
        V3D_WRITE(V3D_TFU_ICFG, job->args.icfg | V3D_TFU_ICFG_IOC);

        return fence;
}

static struct dma_fence *
v3d_csd_job_run(struct drm_sched_job *sched_job)
{
        struct v3d_csd_job *job = to_csd_job(sched_job);
        struct v3d_dev *v3d = job->base.v3d;
        struct drm_device *dev = &v3d->drm;
        struct dma_fence *fence;
        int i;

        v3d->csd_job = job;

        v3d_invalidate_caches(v3d);

        fence = v3d_fence_create(v3d, V3D_CSD);
        if (IS_ERR(fence))
                return NULL;

        if (job->base.irq_fence)
                dma_fence_put(job->base.irq_fence);
        job->base.irq_fence = dma_fence_get(fence);

        trace_v3d_submit_csd(dev, to_v3d_fence(fence)->seqno);

        for (i = 1; i <= 6; i++)
                V3D_CORE_WRITE(0, V3D_CSD_QUEUED_CFG0 + 4 * i, job->args.cfg[i]);
        /* CFG0 write kicks off the job. */
        V3D_CORE_WRITE(0, V3D_CSD_QUEUED_CFG0, job->args.cfg[0]);

        return fence;
}

static struct dma_fence *
v3d_cache_clean_job_run(struct drm_sched_job *sched_job)
{
        struct v3d_job *job = to_v3d_job(sched_job);
        struct v3d_dev *v3d = job->v3d;

        v3d_clean_caches(v3d);

        return NULL;
}

static void
v3d_gpu_reset_for_timeout(struct v3d_dev *v3d, struct drm_sched_job *sched_job)
{
        enum v3d_queue q;

        mutex_lock(&v3d->reset_lock);

        /* block scheduler */
        for (q = 0; q < V3D_MAX_QUEUES; q++)
                drm_sched_stop(&v3d->queue[q].sched, sched_job);

        if (sched_job)
                drm_sched_increase_karma(sched_job);

        /* get the GPU back into the init state */
        v3d_reset(v3d);

        for (q = 0; q < V3D_MAX_QUEUES; q++)
                drm_sched_resubmit_jobs(&v3d->queue[q].sched);

        /* Unblock schedulers and restart their jobs. */
        for (q = 0; q < V3D_MAX_QUEUES; q++) {
                drm_sched_start(&v3d->queue[q].sched, true);
        }

        mutex_unlock(&v3d->reset_lock);
}

/* If the current address or return address have changed, then the GPU
 * has probably made progress and we should delay the reset.  This
 * could fail if the GPU got in an infinite loop in the CL, but that
 * is pretty unlikely outside of an i-g-t testcase.
 */
static void
v3d_cl_job_timedout(struct drm_sched_job *sched_job, enum v3d_queue q,
                    u32 *timedout_ctca, u32 *timedout_ctra)
{
        struct v3d_job *job = to_v3d_job(sched_job);
        struct v3d_dev *v3d = job->v3d;
        u32 ctca = V3D_CORE_READ(0, V3D_CLE_CTNCA(q));
        u32 ctra = V3D_CORE_READ(0, V3D_CLE_CTNRA(q));

        if (*timedout_ctca != ctca || *timedout_ctra != ctra) {
                *timedout_ctca = ctca;
                *timedout_ctra = ctra;
                return;
        }

        v3d_gpu_reset_for_timeout(v3d, sched_job);
}

static void
v3d_bin_job_timedout(struct drm_sched_job *sched_job)
{
        struct v3d_bin_job *job = to_bin_job(sched_job);

        v3d_cl_job_timedout(sched_job, V3D_BIN,
                            &job->timedout_ctca, &job->timedout_ctra);
}

static void
v3d_render_job_timedout(struct drm_sched_job *sched_job)
{
        struct v3d_render_job *job = to_render_job(sched_job);

        v3d_cl_job_timedout(sched_job, V3D_RENDER,
                            &job->timedout_ctca, &job->timedout_ctra);
}

static void
v3d_generic_job_timedout(struct drm_sched_job *sched_job)
{
        struct v3d_job *job = to_v3d_job(sched_job);

        v3d_gpu_reset_for_timeout(job->v3d, sched_job);
}

static void
v3d_csd_job_timedout(struct drm_sched_job *sched_job)
{
        struct v3d_csd_job *job = to_csd_job(sched_job);
        struct v3d_dev *v3d = job->base.v3d;
        u32 batches = V3D_CORE_READ(0, V3D_CSD_CURRENT_CFG4);

        /* If we've made progress, skip reset and let the timer get
         * rearmed.
         */
        if (job->timedout_batches != batches) {
                job->timedout_batches = batches;
                return;
        }

        v3d_gpu_reset_for_timeout(v3d, sched_job);
}

static const struct drm_sched_backend_ops v3d_bin_sched_ops = {
        .dependency = v3d_job_dependency,
        .run_job = v3d_bin_job_run,
        .timedout_job = v3d_bin_job_timedout,
        .free_job = v3d_job_free,
};

static const struct drm_sched_backend_ops v3d_render_sched_ops = {
        .dependency = v3d_job_dependency,
        .run_job = v3d_render_job_run,
        .timedout_job = v3d_render_job_timedout,
        .free_job = v3d_job_free,
};

static const struct drm_sched_backend_ops v3d_tfu_sched_ops = {
        .dependency = v3d_job_dependency,
        .run_job = v3d_tfu_job_run,
        .timedout_job = v3d_generic_job_timedout,
        .free_job = v3d_job_free,
};

static const struct drm_sched_backend_ops v3d_csd_sched_ops = {
        .dependency = v3d_job_dependency,
        .run_job = v3d_csd_job_run,
        .timedout_job = v3d_csd_job_timedout,
        .free_job = v3d_job_free
};

static const struct drm_sched_backend_ops v3d_cache_clean_sched_ops = {
        .dependency = v3d_job_dependency,
        .run_job = v3d_cache_clean_job_run,
        .timedout_job = v3d_generic_job_timedout,
        .free_job = v3d_job_free
};

int
v3d_sched_init(struct v3d_dev *v3d)
{
        int hw_jobs_limit = 1;
        int job_hang_limit = 0;
        int hang_limit_ms = 500;
        int ret;

        ret = drm_sched_init(&v3d->queue[V3D_BIN].sched,
                             &v3d_bin_sched_ops,
                             hw_jobs_limit, job_hang_limit,
                             msecs_to_jiffies(hang_limit_ms),
                             "v3d_bin");
        if (ret) {
                dev_err(v3d->drm.dev, "Failed to create bin scheduler: %d.", ret);
                return ret;
        }

        ret = drm_sched_init(&v3d->queue[V3D_RENDER].sched,
                             &v3d_render_sched_ops,
                             hw_jobs_limit, job_hang_limit,
                             msecs_to_jiffies(hang_limit_ms),
                             "v3d_render");
        if (ret) {
                dev_err(v3d->drm.dev, "Failed to create render scheduler: %d.",
                        ret);
                v3d_sched_fini(v3d);
                return ret;
        }

        ret = drm_sched_init(&v3d->queue[V3D_TFU].sched,
                             &v3d_tfu_sched_ops,
                             hw_jobs_limit, job_hang_limit,
                             msecs_to_jiffies(hang_limit_ms),
                             "v3d_tfu");
        if (ret) {
                dev_err(v3d->drm.dev, "Failed to create TFU scheduler: %d.",
                        ret);
                v3d_sched_fini(v3d);
                return ret;
        }

        if (v3d_has_csd(v3d)) {
                ret = drm_sched_init(&v3d->queue[V3D_CSD].sched,
                                     &v3d_csd_sched_ops,
                                     hw_jobs_limit, job_hang_limit,
                                     msecs_to_jiffies(hang_limit_ms),
                                     "v3d_csd");
                if (ret) {
                        dev_err(v3d->drm.dev, "Failed to create CSD scheduler: %d.",
                                ret);
                        v3d_sched_fini(v3d);
                        return ret;
                }

                ret = drm_sched_init(&v3d->queue[V3D_CACHE_CLEAN].sched,
                                     &v3d_cache_clean_sched_ops,
                                     hw_jobs_limit, job_hang_limit,
                                     msecs_to_jiffies(hang_limit_ms),
                                     "v3d_cache_clean");
                if (ret) {
                        dev_err(v3d->drm.dev, "Failed to create CACHE_CLEAN scheduler: %d.",
                                ret);
                        v3d_sched_fini(v3d);
                        return ret;
                }
        }

        return 0;
}

void
v3d_sched_fini(struct v3d_dev *v3d)
{
        enum v3d_queue q;

        for (q = 0; q < V3D_MAX_QUEUES; q++) {
                if (v3d->queue[q].sched.ready)
                        drm_sched_fini(&v3d->queue[q].sched);
        }
}