[deliverable/linux.git] / drivers / gpu / drm / amd / amdgpu / amdgpu_fence.c

/*
 * Copyright 2009 Jerome Glisse.
 * All Rights Reserved.
 *
 * 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, sub license, 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 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 */
/*
 * Authors:
 *    Jerome Glisse <glisse@freedesktop.org>
 *    Dave Airlie
 */
#include <linux/seq_file.h>
#include <linux/atomic.h>
#include <linux/wait.h>
#include <linux/kref.h>
#include <linux/slab.h>
#include <linux/firmware.h>
#include <drm/drmP.h>
#include "amdgpu.h"
#include "amdgpu_trace.h"

/*
 * Fences
 * Fences mark an event in the GPUs pipeline and are used
 * for GPU/CPU synchronization.  When the fence is written,
 * it is expected that all buffers associated with that fence
 * are no longer in use by the associated ring on the GPU and
 * that the the relevant GPU caches have been flushed.
 */

/**
 * amdgpu_fence_write - write a fence value
 *
 * @ring: ring the fence is associated with
 * @seq: sequence number to write
 *
 * Writes a fence value to memory (all asics).
 */
static void amdgpu_fence_write(struct amdgpu_ring *ring, u32 seq)
{
        struct amdgpu_fence_driver *drv = &ring->fence_drv;

        if (drv->cpu_addr)
                *drv->cpu_addr = cpu_to_le32(seq);
}

/**
 * amdgpu_fence_read - read a fence value
 *
 * @ring: ring the fence is associated with
 *
 * Reads a fence value from memory (all asics).
 * Returns the value of the fence read from memory.
 */
static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
{
        struct amdgpu_fence_driver *drv = &ring->fence_drv;
        u32 seq = 0;

        if (drv->cpu_addr)
                seq = le32_to_cpu(*drv->cpu_addr);
        else
                seq = lower_32_bits(atomic64_read(&drv->last_seq));

        return seq;
}

/**
 * amdgpu_fence_schedule_check - schedule lockup check
 *
 * @ring: pointer to struct amdgpu_ring
 *
 * Queues a delayed work item to check for lockups.
 */
static void amdgpu_fence_schedule_check(struct amdgpu_ring *ring)
{
        /*
         * Do not reset the timer here with mod_delayed_work,
         * this can livelock in an interaction with TTM delayed destroy.
         */
        queue_delayed_work(system_power_efficient_wq,
                &ring->fence_drv.lockup_work,
                AMDGPU_FENCE_JIFFIES_TIMEOUT);
}

/**
 * amdgpu_fence_emit - emit a fence on the requested ring
 *
 * @ring: ring the fence is associated with
 * @owner: creator of the fence
 * @fence: amdgpu fence object
 *
 * Emits a fence command on the requested ring (all asics).
 * Returns 0 on success, -ENOMEM on failure.
 */
int amdgpu_fence_emit(struct amdgpu_ring *ring, void *owner,
                      struct amdgpu_fence **fence)
{
        struct amdgpu_device *adev = ring->adev;

        /* we are protected by the ring emission mutex */
        *fence = kmalloc(sizeof(struct amdgpu_fence), GFP_KERNEL);
        if ((*fence) == NULL) {
                return -ENOMEM;
        }
        (*fence)->seq = ++ring->fence_drv.sync_seq[ring->idx];
        (*fence)->ring = ring;
        (*fence)->owner = owner;
        fence_init(&(*fence)->base, &amdgpu_fence_ops,
                &adev->fence_queue.lock, adev->fence_context + ring->idx,
                (*fence)->seq);
        amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
                               (*fence)->seq,
                               AMDGPU_FENCE_FLAG_INT);
        trace_amdgpu_fence_emit(ring->adev->ddev, ring->idx, (*fence)->seq);
        return 0;
}

/**
 * amdgpu_fence_check_signaled - callback from fence_queue
 *
 * this function is called with fence_queue lock held, which is also used
 * for the fence locking itself, so unlocked variants are used for
 * fence_signal, and remove_wait_queue.
 */
static int amdgpu_fence_check_signaled(wait_queue_t *wait, unsigned mode, int flags, void *key)
{
        struct amdgpu_fence *fence;
        struct amdgpu_device *adev;
        u64 seq;
        int ret;

        fence = container_of(wait, struct amdgpu_fence, fence_wake);
        adev = fence->ring->adev;

        /*
         * We cannot use amdgpu_fence_process here because we're already
         * in the waitqueue, in a call from wake_up_all.
         */
        seq = atomic64_read(&fence->ring->fence_drv.last_seq);
        if (seq >= fence->seq) {
                ret = fence_signal_locked(&fence->base);
                if (!ret)
                        FENCE_TRACE(&fence->base, "signaled from irq context\n");
                else
                        FENCE_TRACE(&fence->base, "was already signaled\n");

                __remove_wait_queue(&adev->fence_queue, &fence->fence_wake);
                fence_put(&fence->base);
        } else
                FENCE_TRACE(&fence->base, "pending\n");
        return 0;
}

/**
 * amdgpu_fence_activity - check for fence activity
 *
 * @ring: pointer to struct amdgpu_ring
 *
 * Checks the current fence value and calculates the last
 * signalled fence value. Returns true if activity occured
 * on the ring, and the fence_queue should be waken up.
 */
static bool amdgpu_fence_activity(struct amdgpu_ring *ring)
{
        uint64_t seq, last_seq, last_emitted;
        unsigned count_loop = 0;
        bool wake = false;

        /* Note there is a scenario here for an infinite loop but it's
         * very unlikely to happen. For it to happen, the current polling
         * process need to be interrupted by another process and another
         * process needs to update the last_seq btw the atomic read and
         * xchg of the current process.
         *
         * More over for this to go in infinite loop there need to be
         * continuously new fence signaled ie amdgpu_fence_read needs
         * to return a different value each time for both the currently
         * polling process and the other process that xchg the last_seq
         * btw atomic read and xchg of the current process. And the
         * value the other process set as last seq must be higher than
         * the seq value we just read. Which means that current process
         * need to be interrupted after amdgpu_fence_read and before
         * atomic xchg.
         *
         * To be even more safe we count the number of time we loop and
         * we bail after 10 loop just accepting the fact that we might
         * have temporarly set the last_seq not to the true real last
         * seq but to an older one.
         */
        last_seq = atomic64_read(&ring->fence_drv.last_seq);
        do {
                last_emitted = ring->fence_drv.sync_seq[ring->idx];
                seq = amdgpu_fence_read(ring);
                seq |= last_seq & 0xffffffff00000000LL;
                if (seq < last_seq) {
                        seq &= 0xffffffff;
                        seq |= last_emitted & 0xffffffff00000000LL;
                }

                if (seq <= last_seq || seq > last_emitted) {
                        break;
                }
                /* If we loop over we don't want to return without
                 * checking if a fence is signaled as it means that the
                 * seq we just read is different from the previous on.
                 */
                wake = true;
                last_seq = seq;
                if ((count_loop++) > 10) {
                        /* We looped over too many time leave with the
                         * fact that we might have set an older fence
                         * seq then the current real last seq as signaled
                         * by the hw.
                         */
                        break;
                }
        } while (atomic64_xchg(&ring->fence_drv.last_seq, seq) > seq);

        if (seq < last_emitted)
                amdgpu_fence_schedule_check(ring);

        return wake;
}

/**
 * amdgpu_fence_check_lockup - check for hardware lockup
 *
 * @work: delayed work item
 *
 * Checks for fence activity and if there is none probe
 * the hardware if a lockup occured.
 */
static void amdgpu_fence_check_lockup(struct work_struct *work)
{
        struct amdgpu_fence_driver *fence_drv;
        struct amdgpu_ring *ring;

        fence_drv = container_of(work, struct amdgpu_fence_driver,
                                lockup_work.work);
        ring = fence_drv->ring;

        if (!down_read_trylock(&ring->adev->exclusive_lock)) {
                /* just reschedule the check if a reset is going on */
                amdgpu_fence_schedule_check(ring);
                return;
        }

        if (amdgpu_fence_activity(ring))
                wake_up_all(&ring->adev->fence_queue);
        else if (amdgpu_ring_is_lockup(ring)) {
                /* good news we believe it's a lockup */
                dev_warn(ring->adev->dev, "GPU lockup (current fence id "
                        "0x%016llx last fence id 0x%016llx on ring %d)\n",
                        (uint64_t)atomic64_read(&fence_drv->last_seq),
                        fence_drv->sync_seq[ring->idx], ring->idx);

                /* remember that we need an reset */
                ring->adev->needs_reset = true;
                wake_up_all(&ring->adev->fence_queue);
        }
        up_read(&ring->adev->exclusive_lock);
}

/**
 * amdgpu_fence_process - process a fence
 *
 * @adev: amdgpu_device pointer
 * @ring: ring index the fence is associated with
 *
 * Checks the current fence value and wakes the fence queue
 * if the sequence number has increased (all asics).
 */
void amdgpu_fence_process(struct amdgpu_ring *ring)
{
        uint64_t seq, last_seq, last_emitted;
        unsigned count_loop = 0;
        bool wake = false;

        /* Note there is a scenario here for an infinite loop but it's
         * very unlikely to happen. For it to happen, the current polling
         * process need to be interrupted by another process and another
         * process needs to update the last_seq btw the atomic read and
         * xchg of the current process.
         *
         * More over for this to go in infinite loop there need to be
         * continuously new fence signaled ie amdgpu_fence_read needs
         * to return a different value each time for both the currently
         * polling process and the other process that xchg the last_seq
         * btw atomic read and xchg of the current process. And the
         * value the other process set as last seq must be higher than
         * the seq value we just read. Which means that current process
         * need to be interrupted after amdgpu_fence_read and before
         * atomic xchg.
         *
         * To be even more safe we count the number of time we loop and
         * we bail after 10 loop just accepting the fact that we might
         * have temporarly set the last_seq not to the true real last
         * seq but to an older one.
         */
        last_seq = atomic64_read(&ring->fence_drv.last_seq);
        do {
                last_emitted = ring->fence_drv.sync_seq[ring->idx];
                seq = amdgpu_fence_read(ring);
                seq |= last_seq & 0xffffffff00000000LL;
                if (seq < last_seq) {
                        seq &= 0xffffffff;
                        seq |= last_emitted & 0xffffffff00000000LL;
                }

                if (seq <= last_seq || seq > last_emitted) {
                        break;
                }
                /* If we loop over we don't want to return without
                 * checking if a fence is signaled as it means that the
                 * seq we just read is different from the previous on.
                 */
                wake = true;
                last_seq = seq;
                if ((count_loop++) > 10) {
                        /* We looped over too many time leave with the
                         * fact that we might have set an older fence
                         * seq then the current real last seq as signaled
                         * by the hw.
                         */
                        break;
                }
        } while (atomic64_xchg(&ring->fence_drv.last_seq, seq) > seq);

        if (wake)
                wake_up_all(&ring->adev->fence_queue);
}

/**
 * amdgpu_fence_seq_signaled - check if a fence sequence number has signaled
 *
 * @ring: ring the fence is associated with
 * @seq: sequence number
 *
 * Check if the last signaled fence sequnce number is >= the requested
 * sequence number (all asics).
 * Returns true if the fence has signaled (current fence value
 * is >= requested value) or false if it has not (current fence
 * value is < the requested value.  Helper function for
 * amdgpu_fence_signaled().
 */
static bool amdgpu_fence_seq_signaled(struct amdgpu_ring *ring, u64 seq)
{
        if (atomic64_read(&ring->fence_drv.last_seq) >= seq)
                return true;

        /* poll new last sequence at least once */
        amdgpu_fence_process(ring);
        if (atomic64_read(&ring->fence_drv.last_seq) >= seq)
                return true;

        return false;
}

static bool amdgpu_fence_is_signaled(struct fence *f)
{
        struct amdgpu_fence *fence = to_amdgpu_fence(f);
        struct amdgpu_ring *ring = fence->ring;
        struct amdgpu_device *adev = ring->adev;

        if (atomic64_read(&ring->fence_drv.last_seq) >= fence->seq)
                return true;

        if (down_read_trylock(&adev->exclusive_lock)) {
                amdgpu_fence_process(ring);
                up_read(&adev->exclusive_lock);

                if (atomic64_read(&ring->fence_drv.last_seq) >= fence->seq)
                        return true;
        }
        return false;
}

/**
 * amdgpu_fence_enable_signaling - enable signalling on fence
 * @fence: fence
 *
 * This function is called with fence_queue lock held, and adds a callback
 * to fence_queue that checks if this fence is signaled, and if so it
 * signals the fence and removes itself.
 */
static bool amdgpu_fence_enable_signaling(struct fence *f)
{
        struct amdgpu_fence *fence = to_amdgpu_fence(f);
        struct amdgpu_ring *ring = fence->ring;
        struct amdgpu_device *adev = ring->adev;

        if (atomic64_read(&ring->fence_drv.last_seq) >= fence->seq)
                return false;

        fence->fence_wake.flags = 0;
        fence->fence_wake.private = NULL;
        fence->fence_wake.func = amdgpu_fence_check_signaled;
        __add_wait_queue(&adev->fence_queue, &fence->fence_wake);
        fence_get(f);
        FENCE_TRACE(&fence->base, "armed on ring %i!\n", ring->idx);
        return true;
}

/**
 * amdgpu_fence_signaled - check if a fence has signaled
 *
 * @fence: amdgpu fence object
 *
 * Check if the requested fence has signaled (all asics).
 * Returns true if the fence has signaled or false if it has not.
 */
bool amdgpu_fence_signaled(struct amdgpu_fence *fence)
{
        if (!fence)
                return true;

        if (amdgpu_fence_seq_signaled(fence->ring, fence->seq)) {
                if (!fence_signal(&fence->base))
                        FENCE_TRACE(&fence->base, "signaled from amdgpu_fence_signaled\n");
                return true;
        }

        return false;
}

/**
 * amdgpu_fence_any_seq_signaled - check if any sequence number is signaled
 *
 * @adev: amdgpu device pointer
 * @seq: sequence numbers
 *
 * Check if the last signaled fence sequnce number is >= the requested
 * sequence number (all asics).
 * Returns true if any has signaled (current value is >= requested value)
 * or false if it has not. Helper function for amdgpu_fence_wait_seq.
 */
static bool amdgpu_fence_any_seq_signaled(struct amdgpu_device *adev, u64 *seq)
{
        unsigned i;

        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                if (!adev->rings[i] || !seq[i])
                        continue;

                if (amdgpu_fence_seq_signaled(adev->rings[i], seq[i]))
                        return true;
        }

        return false;
}

/**
 * amdgpu_fence_wait_seq_timeout - wait for a specific sequence numbers
 *
 * @adev: amdgpu device pointer
 * @target_seq: sequence number(s) we want to wait for
 * @intr: use interruptable sleep
 * @timeout: maximum time to wait, or MAX_SCHEDULE_TIMEOUT for infinite wait
 *
 * Wait for the requested sequence number(s) to be written by any ring
 * (all asics).  Sequnce number array is indexed by ring id.
 * @intr selects whether to use interruptable (true) or non-interruptable
 * (false) sleep when waiting for the sequence number.  Helper function
 * for amdgpu_fence_wait_*().
 * Returns remaining time if the sequence number has passed, 0 when
 * the wait timeout, or an error for all other cases.
 * -EDEADLK is returned when a GPU lockup has been detected.
 */
static long amdgpu_fence_wait_seq_timeout(struct amdgpu_device *adev,
                                          u64 *target_seq, bool intr,
                                          long timeout)
{
        uint64_t last_seq[AMDGPU_MAX_RINGS];
        bool signaled;
        int i;
        long r;

        if (timeout == 0) {
                return amdgpu_fence_any_seq_signaled(adev, target_seq);
        }

        while (!amdgpu_fence_any_seq_signaled(adev, target_seq)) {

                /* Save current sequence values, used to check for GPU lockups */
                for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                        struct amdgpu_ring *ring = adev->rings[i];

                        if (!ring || !target_seq[i])
                                continue;

                        last_seq[i] = atomic64_read(&ring->fence_drv.last_seq);
                        trace_amdgpu_fence_wait_begin(adev->ddev, i, target_seq[i]);
                }

                if (intr) {
                        r = wait_event_interruptible_timeout(adev->fence_queue, (
                                (signaled = amdgpu_fence_any_seq_signaled(adev, target_seq))
                                 || adev->needs_reset), AMDGPU_FENCE_JIFFIES_TIMEOUT);
                } else {
                        r = wait_event_timeout(adev->fence_queue, (
                                (signaled = amdgpu_fence_any_seq_signaled(adev, target_seq))
                                 || adev->needs_reset), AMDGPU_FENCE_JIFFIES_TIMEOUT);
                }

                for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                        struct amdgpu_ring *ring = adev->rings[i];

                        if (!ring || !target_seq[i])
                                continue;

                        trace_amdgpu_fence_wait_end(adev->ddev, i, target_seq[i]);
                }

                if (unlikely(r < 0))
                        return r;

                if (unlikely(!signaled)) {

                        if (adev->needs_reset)
                                return -EDEADLK;

                        /* we were interrupted for some reason and fence
                         * isn't signaled yet, resume waiting */
                        if (r)
                                continue;

                        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                                struct amdgpu_ring *ring = adev->rings[i];

                                if (!ring || !target_seq[i])
                                        continue;

                                if (last_seq[i] != atomic64_read(&ring->fence_drv.last_seq))
                                        break;
                        }

                        if (i != AMDGPU_MAX_RINGS)
                                continue;

                        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                                if (!adev->rings[i] || !target_seq[i])
                                        continue;

                                if (amdgpu_ring_is_lockup(adev->rings[i]))
                                        break;
                        }

                        if (i < AMDGPU_MAX_RINGS) {
                                /* good news we believe it's a lockup */
                                dev_warn(adev->dev, "GPU lockup (waiting for "
                                         "0x%016llx last fence id 0x%016llx on"
                                         " ring %d)\n",
                                         target_seq[i], last_seq[i], i);

                                /* remember that we need an reset */
                                adev->needs_reset = true;
                                wake_up_all(&adev->fence_queue);
                                return -EDEADLK;
                        }

                        if (timeout < MAX_SCHEDULE_TIMEOUT) {
                                timeout -= AMDGPU_FENCE_JIFFIES_TIMEOUT;
                                if (timeout <= 0) {
                                        return 0;
                                }
                        }
                }
        }
        return timeout;
}

/**
 * amdgpu_fence_wait - wait for a fence to signal
 *
 * @fence: amdgpu fence object
 * @intr: use interruptable sleep
 *
 * Wait for the requested fence to signal (all asics).
 * @intr selects whether to use interruptable (true) or non-interruptable
 * (false) sleep when waiting for the fence.
 * Returns 0 if the fence has passed, error for all other cases.
 */
int amdgpu_fence_wait(struct amdgpu_fence *fence, bool intr)
{
        uint64_t seq[AMDGPU_MAX_RINGS] = {};
        long r;

        seq[fence->ring->idx] = fence->seq;
        r = amdgpu_fence_wait_seq_timeout(fence->ring->adev, seq, intr, MAX_SCHEDULE_TIMEOUT);
        if (r < 0) {
                return r;
        }

        r = fence_signal(&fence->base);
        if (!r)
                FENCE_TRACE(&fence->base, "signaled from fence_wait\n");
        return 0;
}

/**
 * amdgpu_fence_wait_any - wait for a fence to signal on any ring
 *
 * @adev: amdgpu device pointer
 * @fences: amdgpu fence object(s)
 * @intr: use interruptable sleep
 *
 * Wait for any requested fence to signal (all asics).  Fence
 * array is indexed by ring id.  @intr selects whether to use
 * interruptable (true) or non-interruptable (false) sleep when
 * waiting for the fences. Used by the suballocator.
 * Returns 0 if any fence has passed, error for all other cases.
 */
int amdgpu_fence_wait_any(struct amdgpu_device *adev,
                          struct amdgpu_fence **fences,
                          bool intr)
{
        uint64_t seq[AMDGPU_MAX_RINGS];
        unsigned i, num_rings = 0;
        long r;

        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                seq[i] = 0;

                if (!fences[i]) {
                        continue;
                }

                seq[i] = fences[i]->seq;
                ++num_rings;
        }

        /* nothing to wait for ? */
        if (num_rings == 0)
                return -ENOENT;

        r = amdgpu_fence_wait_seq_timeout(adev, seq, intr, MAX_SCHEDULE_TIMEOUT);
        if (r < 0) {
                return r;
        }
        return 0;
}

/**
 * amdgpu_fence_wait_next - wait for the next fence to signal
 *
 * @adev: amdgpu device pointer
 * @ring: ring index the fence is associated with
 *
 * Wait for the next fence on the requested ring to signal (all asics).
 * Returns 0 if the next fence has passed, error for all other cases.
 * Caller must hold ring lock.
 */
int amdgpu_fence_wait_next(struct amdgpu_ring *ring)
{
        uint64_t seq[AMDGPU_MAX_RINGS] = {};
        long r;

        seq[ring->idx] = atomic64_read(&ring->fence_drv.last_seq) + 1ULL;
        if (seq[ring->idx] >= ring->fence_drv.sync_seq[ring->idx]) {
                /* nothing to wait for, last_seq is
                   already the last emited fence */
                return -ENOENT;
        }
        r = amdgpu_fence_wait_seq_timeout(ring->adev, seq, false, MAX_SCHEDULE_TIMEOUT);
        if (r < 0)
                return r;
        return 0;
}

/**
 * amdgpu_fence_wait_empty - wait for all fences to signal
 *
 * @adev: amdgpu device pointer
 * @ring: ring index the fence is associated with
 *
 * Wait for all fences on the requested ring to signal (all asics).
 * Returns 0 if the fences have passed, error for all other cases.
 * Caller must hold ring lock.
 */
int amdgpu_fence_wait_empty(struct amdgpu_ring *ring)
{
        struct amdgpu_device *adev = ring->adev;
        uint64_t seq[AMDGPU_MAX_RINGS] = {};
        long r;

        seq[ring->idx] = ring->fence_drv.sync_seq[ring->idx];
        if (!seq[ring->idx])
                return 0;

        r = amdgpu_fence_wait_seq_timeout(adev, seq, false, MAX_SCHEDULE_TIMEOUT);
        if (r < 0) {
                if (r == -EDEADLK)
                        return -EDEADLK;

                dev_err(adev->dev, "error waiting for ring[%d] to become idle (%ld)\n",
                        ring->idx, r);
        }
        return 0;
}

/**
 * amdgpu_fence_ref - take a ref on a fence
 *
 * @fence: amdgpu fence object
 *
 * Take a reference on a fence (all asics).
 * Returns the fence.
 */
struct amdgpu_fence *amdgpu_fence_ref(struct amdgpu_fence *fence)
{
        fence_get(&fence->base);
        return fence;
}

/**
 * amdgpu_fence_unref - remove a ref on a fence
 *
 * @fence: amdgpu fence object
 *
 * Remove a reference on a fence (all asics).
 */
void amdgpu_fence_unref(struct amdgpu_fence **fence)
{
        struct amdgpu_fence *tmp = *fence;

        *fence = NULL;
        if (tmp)
                fence_put(&tmp->base);
}

/**
 * amdgpu_fence_count_emitted - get the count of emitted fences
 *
 * @ring: ring the fence is associated with
 *
 * Get the number of fences emitted on the requested ring (all asics).
 * Returns the number of emitted fences on the ring.  Used by the
 * dynpm code to ring track activity.
 */
unsigned amdgpu_fence_count_emitted(struct amdgpu_ring *ring)
{
        uint64_t emitted;

        /* We are not protected by ring lock when reading the last sequence
         * but it's ok to report slightly wrong fence count here.
         */
        amdgpu_fence_process(ring);
        emitted = ring->fence_drv.sync_seq[ring->idx]
                - atomic64_read(&ring->fence_drv.last_seq);
        /* to avoid 32bits warp around */
        if (emitted > 0x10000000)
                emitted = 0x10000000;

        return (unsigned)emitted;
}

/**
 * amdgpu_fence_need_sync - do we need a semaphore
 *
 * @fence: amdgpu fence object
 * @dst_ring: which ring to check against
 *
 * Check if the fence needs to be synced against another ring
 * (all asics).  If so, we need to emit a semaphore.
 * Returns true if we need to sync with another ring, false if
 * not.
 */
bool amdgpu_fence_need_sync(struct amdgpu_fence *fence,
                            struct amdgpu_ring *dst_ring)
{
        struct amdgpu_fence_driver *fdrv;

        if (!fence)
                return false;

        if (fence->ring == dst_ring)
                return false;

        /* we are protected by the ring mutex */
        fdrv = &dst_ring->fence_drv;
        if (fence->seq <= fdrv->sync_seq[fence->ring->idx])
                return false;

        return true;
}

/**
 * amdgpu_fence_note_sync - record the sync point
 *
 * @fence: amdgpu fence object
 * @dst_ring: which ring to check against
 *
 * Note the sequence number at which point the fence will
 * be synced with the requested ring (all asics).
 */
void amdgpu_fence_note_sync(struct amdgpu_fence *fence,
                            struct amdgpu_ring *dst_ring)
{
        struct amdgpu_fence_driver *dst, *src;
        unsigned i;

        if (!fence)
                return;

        if (fence->ring == dst_ring)
                return;

        /* we are protected by the ring mutex */
        src = &fence->ring->fence_drv;
        dst = &dst_ring->fence_drv;
        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                if (i == dst_ring->idx)
                        continue;

                dst->sync_seq[i] = max(dst->sync_seq[i], src->sync_seq[i]);
        }
}

/**
 * amdgpu_fence_driver_start_ring - make the fence driver
 * ready for use on the requested ring.
 *
 * @ring: ring to start the fence driver on
 * @irq_src: interrupt source to use for this ring
 * @irq_type: interrupt type to use for this ring
 *
 * Make the fence driver ready for processing (all asics).
 * Not all asics have all rings, so each asic will only
 * start the fence driver on the rings it has.
 * Returns 0 for success, errors for failure.
 */
int amdgpu_fence_driver_start_ring(struct amdgpu_ring *ring,
                                   struct amdgpu_irq_src *irq_src,
                                   unsigned irq_type)
{
        struct amdgpu_device *adev = ring->adev;
        uint64_t index;

        if (ring != &adev->uvd.ring) {
                ring->fence_drv.cpu_addr = &adev->wb.wb[ring->fence_offs];
                ring->fence_drv.gpu_addr = adev->wb.gpu_addr + (ring->fence_offs * 4);
        } else {
                /* put fence directly behind firmware */
                index = ALIGN(adev->uvd.fw->size, 8);
                ring->fence_drv.cpu_addr = adev->uvd.cpu_addr + index;
                ring->fence_drv.gpu_addr = adev->uvd.gpu_addr + index;
        }
        amdgpu_fence_write(ring, atomic64_read(&ring->fence_drv.last_seq));
        amdgpu_irq_get(adev, irq_src, irq_type);

        ring->fence_drv.irq_src = irq_src;
        ring->fence_drv.irq_type = irq_type;
        ring->fence_drv.initialized = true;

        dev_info(adev->dev, "fence driver on ring %d use gpu addr 0x%016llx, "
                 "cpu addr 0x%p\n", ring->idx,
                 ring->fence_drv.gpu_addr, ring->fence_drv.cpu_addr);
        return 0;
}

/**
 * amdgpu_fence_driver_init_ring - init the fence driver
 * for the requested ring.
 *
 * @ring: ring to init the fence driver on
 *
 * Init the fence driver for the requested ring (all asics).
 * Helper function for amdgpu_fence_driver_init().
 */
void amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring)
{
        int i;

        ring->fence_drv.cpu_addr = NULL;
        ring->fence_drv.gpu_addr = 0;
        for (i = 0; i < AMDGPU_MAX_RINGS; ++i)
                ring->fence_drv.sync_seq[i] = 0;

        atomic64_set(&ring->fence_drv.last_seq, 0);
        ring->fence_drv.initialized = false;

        INIT_DELAYED_WORK(&ring->fence_drv.lockup_work,
                        amdgpu_fence_check_lockup);
        ring->fence_drv.ring = ring;

        if (amdgpu_enable_scheduler) {
                ring->scheduler = amd_sched_create((void *)ring->adev,
                                                   NULL, ring->idx, 5, 0);
                if (!ring->scheduler)
                        DRM_ERROR("Failed to create scheduler on ring %d.\n",
                                  ring->idx);
        }
}

/**
 * amdgpu_fence_driver_init - init the fence driver
 * for all possible rings.
 *
 * @adev: amdgpu device pointer
 *
 * Init the fence driver for all possible rings (all asics).
 * Not all asics have all rings, so each asic will only
 * start the fence driver on the rings it has using
 * amdgpu_fence_driver_start_ring().
 * Returns 0 for success.
 */
int amdgpu_fence_driver_init(struct amdgpu_device *adev)
{
        init_waitqueue_head(&adev->fence_queue);
        if (amdgpu_debugfs_fence_init(adev))
                dev_err(adev->dev, "fence debugfs file creation failed\n");

        return 0;
}

/**
 * amdgpu_fence_driver_fini - tear down the fence driver
 * for all possible rings.
 *
 * @adev: amdgpu device pointer
 *
 * Tear down the fence driver for all possible rings (all asics).
 */
void amdgpu_fence_driver_fini(struct amdgpu_device *adev)
{
        int i, r;

        mutex_lock(&adev->ring_lock);
        for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
                struct amdgpu_ring *ring = adev->rings[i];
                if (!ring || !ring->fence_drv.initialized)
                        continue;
                r = amdgpu_fence_wait_empty(ring);
                if (r) {
                        /* no need to trigger GPU reset as we are unloading */
                        amdgpu_fence_driver_force_completion(adev);
                }
                wake_up_all(&adev->fence_queue);
                amdgpu_irq_put(adev, ring->fence_drv.irq_src,
                               ring->fence_drv.irq_type);
                if (ring->scheduler)
                        amd_sched_destroy(ring->scheduler);
                ring->fence_drv.initialized = false;
        }
        mutex_unlock(&adev->ring_lock);
}

/**
 * amdgpu_fence_driver_suspend - suspend the fence driver
 * for all possible rings.
 *
 * @adev: amdgpu device pointer
 *
 * Suspend the fence driver for all possible rings (all asics).
 */
void amdgpu_fence_driver_suspend(struct amdgpu_device *adev)
{
        int i, r;

        mutex_lock(&adev->ring_lock);
        for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
                struct amdgpu_ring *ring = adev->rings[i];
                if (!ring || !ring->fence_drv.initialized)
                        continue;

                /* wait for gpu to finish processing current batch */
                r = amdgpu_fence_wait_empty(ring);
                if (r) {
                        /* delay GPU reset to resume */
                        amdgpu_fence_driver_force_completion(adev);
                }

                /* disable the interrupt */
                amdgpu_irq_put(adev, ring->fence_drv.irq_src,
                               ring->fence_drv.irq_type);
        }
        mutex_unlock(&adev->ring_lock);
}

/**
 * amdgpu_fence_driver_resume - resume the fence driver
 * for all possible rings.
 *
 * @adev: amdgpu device pointer
 *
 * Resume the fence driver for all possible rings (all asics).
 * Not all asics have all rings, so each asic will only
 * start the fence driver on the rings it has using
 * amdgpu_fence_driver_start_ring().
 * Returns 0 for success.
 */
void amdgpu_fence_driver_resume(struct amdgpu_device *adev)
{
        int i;

        mutex_lock(&adev->ring_lock);
        for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
                struct amdgpu_ring *ring = adev->rings[i];
                if (!ring || !ring->fence_drv.initialized)
                        continue;

                /* enable the interrupt */
                amdgpu_irq_get(adev, ring->fence_drv.irq_src,
                               ring->fence_drv.irq_type);
        }
        mutex_unlock(&adev->ring_lock);
}

/**
 * amdgpu_fence_driver_force_completion - force all fence waiter to complete
 *
 * @adev: amdgpu device pointer
 *
 * In case of GPU reset failure make sure no process keep waiting on fence
 * that will never complete.
 */
void amdgpu_fence_driver_force_completion(struct amdgpu_device *adev)
{
        int i;

        for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
                struct amdgpu_ring *ring = adev->rings[i];
                if (!ring || !ring->fence_drv.initialized)
                        continue;

                amdgpu_fence_write(ring, ring->fence_drv.sync_seq[i]);
        }
}


/*
 * Fence debugfs
 */
#if defined(CONFIG_DEBUG_FS)
static int amdgpu_debugfs_fence_info(struct seq_file *m, void *data)
{
        struct drm_info_node *node = (struct drm_info_node *)m->private;
        struct drm_device *dev = node->minor->dev;
        struct amdgpu_device *adev = dev->dev_private;
        int i, j;

        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                struct amdgpu_ring *ring = adev->rings[i];
                if (!ring || !ring->fence_drv.initialized)
                        continue;

                amdgpu_fence_process(ring);

                seq_printf(m, "--- ring %d (%s) ---\n", i, ring->name);
                seq_printf(m, "Last signaled fence 0x%016llx\n",
                           (unsigned long long)atomic64_read(&ring->fence_drv.last_seq));
                seq_printf(m, "Last emitted        0x%016llx\n",
                           ring->fence_drv.sync_seq[i]);

                for (j = 0; j < AMDGPU_MAX_RINGS; ++j) {
                        struct amdgpu_ring *other = adev->rings[j];
                        if (i != j && other && other->fence_drv.initialized &&
                            ring->fence_drv.sync_seq[j])
                                seq_printf(m, "Last sync to ring %d 0x%016llx\n",
                                           j, ring->fence_drv.sync_seq[j]);
                }
        }
        return 0;
}

static struct drm_info_list amdgpu_debugfs_fence_list[] = {
        {"amdgpu_fence_info", &amdgpu_debugfs_fence_info, 0, NULL},
};
#endif

int amdgpu_debugfs_fence_init(struct amdgpu_device *adev)
{
#if defined(CONFIG_DEBUG_FS)
        return amdgpu_debugfs_add_files(adev, amdgpu_debugfs_fence_list, 1);
#else
        return 0;
#endif
}

static const char *amdgpu_fence_get_driver_name(struct fence *fence)
{
        return "amdgpu";
}

static const char *amdgpu_fence_get_timeline_name(struct fence *f)
{
        struct amdgpu_fence *fence = to_amdgpu_fence(f);
        return (const char *)fence->ring->name;
}

static inline bool amdgpu_test_signaled(struct amdgpu_fence *fence)
{
        return test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->base.flags);
}

struct amdgpu_wait_cb {
        struct fence_cb base;
        struct task_struct *task;
};

static void amdgpu_fence_wait_cb(struct fence *fence, struct fence_cb *cb)
{
        struct amdgpu_wait_cb *wait =
                container_of(cb, struct amdgpu_wait_cb, base);
        wake_up_process(wait->task);
}

static signed long amdgpu_fence_default_wait(struct fence *f, bool intr,
                                             signed long t)
{
        struct amdgpu_fence *fence = to_amdgpu_fence(f);
        struct amdgpu_device *adev = fence->ring->adev;
        struct amdgpu_wait_cb cb;

        cb.task = current;

        if (fence_add_callback(f, &cb.base, amdgpu_fence_wait_cb))
                return t;

        while (t > 0) {
                if (intr)
                        set_current_state(TASK_INTERRUPTIBLE);
                else
                        set_current_state(TASK_UNINTERRUPTIBLE);

                /*
                 * amdgpu_test_signaled must be called after
                 * set_current_state to prevent a race with wake_up_process
                 */
                if (amdgpu_test_signaled(fence))
                        break;

                if (adev->needs_reset) {
                        t = -EDEADLK;
                        break;
                }

                t = schedule_timeout(t);

                if (t > 0 && intr && signal_pending(current))
                        t = -ERESTARTSYS;
        }

        __set_current_state(TASK_RUNNING);
        fence_remove_callback(f, &cb.base);

        return t;
}

const struct fence_ops amdgpu_fence_ops = {
        .get_driver_name = amdgpu_fence_get_driver_name,
        .get_timeline_name = amdgpu_fence_get_timeline_name,
        .enable_signaling = amdgpu_fence_enable_signaling,
        .signaled = amdgpu_fence_is_signaled,
        .wait = amdgpu_fence_default_wait,
        .release = NULL,
};