/*
 * Copyright © 2014 Broadcom
 *
 * 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 (including the next
 * paragraph) 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 AUTHORS OR COPYRIGHT HOLDERS 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.
 */

/**
 * DOC: Interrupt management for the V3D engine
 *
 * We have an interrupt status register (V3D_INTCTL) which reports
 * interrupts, and where writing 1 bits clears those interrupts.
 * There are also a pair of interrupt registers
 * (V3D_INTENA/V3D_INTDIS) where writing a 1 to their bits enables or
 * disables that specific interrupt, and 0s written are ignored
 * (reading either one returns the set of enabled interrupts).
 *
 * When we take a binning flush done interrupt, we need to submit the
 * next frame for binning and move the finished frame to the render
 * thread.
 *
 * When we take a render frame interrupt, we need to wake the
 * processes waiting for some frame to be done, and get the next frame
 * submitted ASAP (so the hardware doesn't sit idle when there's work
 * to do).
 *
 * When we take the binner out of memory interrupt, we need to
 * allocate some new memory and pass it to the binner so that the
 * current job can make progress.
 */

#include "vc4_drv.h"
#include "vc4_regs.h"

#define V3D_DRIVER_IRQS (V3D_INT_OUTOMEM | \
                         V3D_INT_FLDONE | \
                         V3D_INT_FRDONE)

DECLARE_WAIT_QUEUE_HEAD(render_wait);

static void
vc4_overflow_mem_work(struct work_struct *work)
{
        struct vc4_dev *vc4 =
                container_of(work, struct vc4_dev, overflow_mem_work);
        struct vc4_bo *bo = vc4->bin_bo;
        int bin_bo_slot;
        struct vc4_exec_info *exec;
        unsigned long irqflags;

        bin_bo_slot = vc4_v3d_get_bin_slot(vc4);
        if (bin_bo_slot < 0) {
                DRM_ERROR("Couldn't allocate binner overflow mem\n");
                return;
        }

        spin_lock_irqsave(&vc4->job_lock, irqflags);

        if (vc4->bin_alloc_overflow) {
                /* If we had overflow memory allocated previously,
                 * then that chunk will free when the current bin job
                 * is done.  If we don't have a bin job running, then
                 * the chunk will be done whenever the list of render
                 * jobs has drained.
                 */
                exec = vc4_first_bin_job(vc4);
                if (!exec)
                        exec = vc4_last_render_job(vc4);
                if (exec) {
                        exec->bin_slots |= vc4->bin_alloc_overflow;
                } else {
                        /* There's nothing queued in the hardware, so
                         * the old slot is free immediately.
                         */
                        vc4->bin_alloc_used &= ~vc4->bin_alloc_overflow;
                }
        }
        vc4->bin_alloc_overflow = BIT(bin_bo_slot);

        V3D_WRITE(V3D_BPOA, bo->base.paddr + bin_bo_slot * vc4->bin_alloc_size);
        V3D_WRITE(V3D_BPOS, bo->base.base.size);
        V3D_WRITE(V3D_INTCTL, V3D_INT_OUTOMEM);
        V3D_WRITE(V3D_INTENA, V3D_INT_OUTOMEM);
        spin_unlock_irqrestore(&vc4->job_lock, irqflags);
}

static void
vc4_irq_finish_bin_job(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_exec_info *next, *exec = vc4_first_bin_job(vc4);

        if (!exec)
                return;

        vc4_move_job_to_render(dev, exec);
        next = vc4_first_bin_job(vc4);

        /* Only submit the next job in the bin list if it matches the perfmon
         * attached to the one that just finished (or if both jobs don't have
         * perfmon attached to them).
         */
        if (next && next->perfmon == exec->perfmon)
                vc4_submit_next_bin_job(dev);
}

static void
vc4_cancel_bin_job(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_exec_info *exec = vc4_first_bin_job(vc4);

        if (!exec)
                return;

        /* Stop the perfmon so that the next bin job can be started. */
        if (exec->perfmon)
                vc4_perfmon_stop(vc4, exec->perfmon, false);

        list_move_tail(&exec->head, &vc4->bin_job_list);
        vc4_submit_next_bin_job(dev);
}

static void
vc4_irq_finish_render_job(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_exec_info *exec = vc4_first_render_job(vc4);
        struct vc4_exec_info *nextbin, *nextrender;

        if (!exec)
                return;

        vc4->finished_seqno++;
        list_move_tail(&exec->head, &vc4->job_done_list);

        nextbin = vc4_first_bin_job(vc4);
        nextrender = vc4_first_render_job(vc4);

        /* Only stop the perfmon if following jobs in the queue don't expect it
         * to be enabled.
         */
        if (exec->perfmon && !nextrender &&
            (!nextbin || nextbin->perfmon != exec->perfmon))
                vc4_perfmon_stop(vc4, exec->perfmon, true);

        /* If there's a render job waiting, start it. If this is not the case
         * we may have to unblock the binner if it's been stalled because of
         * perfmon (this can be checked by comparing the perfmon attached to
         * the finished renderjob to the one attached to the next bin job: if
         * they don't match, this means the binner is stalled and should be
         * restarted).
         */
        if (nextrender)
                vc4_submit_next_render_job(dev);
        else if (nextbin && nextbin->perfmon != exec->perfmon)
                vc4_submit_next_bin_job(dev);

        if (exec->fence) {
                dma_fence_signal_locked(exec->fence);
                dma_fence_put(exec->fence);
                exec->fence = NULL;
        }

        wake_up_all(&vc4->job_wait_queue);
        schedule_work(&vc4->job_done_work);
}

irqreturn_t
vc4_irq(int irq, void *arg)
{
        struct drm_device *dev = arg;
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        uint32_t intctl;
        irqreturn_t status = IRQ_NONE;

        barrier();
        intctl = V3D_READ(V3D_INTCTL);

        /* Acknowledge the interrupts we're handling here. The binner
         * last flush / render frame done interrupt will be cleared,
         * while OUTOMEM will stay high until the underlying cause is
         * cleared.
         */
        V3D_WRITE(V3D_INTCTL, intctl);

        if (intctl & V3D_INT_OUTOMEM) {
                /* Disable OUTOMEM until the work is done. */
                V3D_WRITE(V3D_INTDIS, V3D_INT_OUTOMEM);
                schedule_work(&vc4->overflow_mem_work);
                status = IRQ_HANDLED;
        }

        if (intctl & V3D_INT_FLDONE) {
                spin_lock(&vc4->job_lock);
                vc4_irq_finish_bin_job(dev);
                spin_unlock(&vc4->job_lock);
                status = IRQ_HANDLED;
        }

        if (intctl & V3D_INT_FRDONE) {
                spin_lock(&vc4->job_lock);
                vc4_irq_finish_render_job(dev);
                spin_unlock(&vc4->job_lock);
                status = IRQ_HANDLED;
        }

        return status;
}

void
vc4_irq_preinstall(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);

        init_waitqueue_head(&vc4->job_wait_queue);
        INIT_WORK(&vc4->overflow_mem_work, vc4_overflow_mem_work);

        /* Clear any pending interrupts someone might have left around
         * for us.
         */
        V3D_WRITE(V3D_INTCTL, V3D_DRIVER_IRQS);
}

int
vc4_irq_postinstall(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);

        /* Enable both the render done and out of memory interrupts. */
        V3D_WRITE(V3D_INTENA, V3D_DRIVER_IRQS);

        return 0;
}

void
vc4_irq_uninstall(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);

        /* Disable sending interrupts for our driver's IRQs. */
        V3D_WRITE(V3D_INTDIS, V3D_DRIVER_IRQS);

        /* Clear any pending interrupts we might have left. */
        V3D_WRITE(V3D_INTCTL, V3D_DRIVER_IRQS);

        /* Finish any interrupt handler still in flight. */
        disable_irq(dev->irq);

        cancel_work_sync(&vc4->overflow_mem_work);
}

/** Reinitializes interrupt registers when a GPU reset is performed. */
void vc4_irq_reset(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        unsigned long irqflags;

        /* Acknowledge any stale IRQs. */
        V3D_WRITE(V3D_INTCTL, V3D_DRIVER_IRQS);

        /*
         * Turn all our interrupts on.  Binner out of memory is the
         * only one we expect to trigger at this point, since we've
         * just come from poweron and haven't supplied any overflow
         * memory yet.
         */
        V3D_WRITE(V3D_INTENA, V3D_DRIVER_IRQS);

        spin_lock_irqsave(&vc4->job_lock, irqflags);
        vc4_cancel_bin_job(dev);
        vc4_irq_finish_render_job(dev);
        spin_unlock_irqrestore(&vc4->job_lock, irqflags);
}