xref: /dragonfly/sys/dev/drm/radeon/radeon_fence.c (revision 3f2dd94a569761201b5b0a18b2f697f97fe1b9dc)

/*
 * 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/firmware.h>
#include <drm/drmP.h>
#include "radeon_reg.h"
#include "radeon.h"
#include "radeon_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.  Whether
 * we use a scratch register or memory location depends on the asic
 * and whether writeback is enabled.
 */

/**
 * radeon_fence_write - write a fence value
 *
 * @rdev: radeon_device pointer
 * @seq: sequence number to write
 * @ring: ring index the fence is associated with
 *
 * Writes a fence value to memory or a scratch register (all asics).
 */
static void radeon_fence_write(struct radeon_device *rdev, u32 seq, int ring)
{
          struct radeon_fence_driver *drv = &rdev->fence_drv[ring];
          if (likely(rdev->wb.enabled || !drv->scratch_reg)) {
                    if (drv->cpu_addr) {
                              *drv->cpu_addr = cpu_to_le32(seq);
                    }
          } else {
                    WREG32(drv->scratch_reg, seq);
          }
}

/**
 * radeon_fence_read - read a fence value
 *
 * @rdev: radeon_device pointer
 * @ring: ring index the fence is associated with
 *
 * Reads a fence value from memory or a scratch register (all asics).
 * Returns the value of the fence read from memory or register.
 */
static u32 radeon_fence_read(struct radeon_device *rdev, int ring)
{
          struct radeon_fence_driver *drv = &rdev->fence_drv[ring];
          u32 seq = 0;

          if (likely(rdev->wb.enabled || !drv->scratch_reg)) {
                    if (drv->cpu_addr) {
                              seq = le32_to_cpu(*drv->cpu_addr);
                    } else {
                              seq = lower_32_bits(atomic64_read(&drv->last_seq));
                    }
          } else {
                    seq = RREG32(drv->scratch_reg);
          }
          return seq;
}

/**
 * radeon_fence_schedule_check - schedule lockup check
 *
 * @rdev: radeon_device pointer
 * @ring: ring index we should work with
 *
 * Queues a delayed work item to check for lockups.
 */
static void radeon_fence_schedule_check(struct radeon_device *rdev, int 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,
                                 &rdev->fence_drv[ring].lockup_work,
                                 RADEON_FENCE_JIFFIES_TIMEOUT);
}

/**
 * radeon_fence_emit - emit a fence on the requested ring
 *
 * @rdev: radeon_device pointer
 * @fence: radeon fence object
 * @ring: ring index the fence is associated with
 *
 * Emits a fence command on the requested ring (all asics).
 * Returns 0 on success, -ENOMEM on failure.
 */
int radeon_fence_emit(struct radeon_device *rdev,
                          struct radeon_fence **fence,
                          int ring)
{
          u64 seq;

          /* we are protected by the ring emission mutex */
          *fence = kmalloc(sizeof(struct radeon_fence), M_DRM, M_WAITOK);
          if ((*fence) == NULL) {
                    return -ENOMEM;
          }
          (*fence)->rdev = rdev;
          (*fence)->seq = seq = ++rdev->fence_drv[ring].sync_seq[ring];
          (*fence)->ring = ring;
          (*fence)->is_vm_update = false;
          dma_fence_init(&(*fence)->base, &radeon_fence_ops,
                           &rdev->fence_queue.lock,
                           rdev->fence_context + ring,
                           seq);
          radeon_fence_ring_emit(rdev, ring, *fence);
          trace_radeon_fence_emit(rdev->ddev, ring, (*fence)->seq);
          radeon_fence_schedule_check(rdev, ring);
          return 0;
}

/**
 * radeon_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 radeon_fence_check_signaled(wait_queue_entry_t *wait, unsigned mode, int flags, void *key)
{
          struct radeon_fence *fence;
          u64 seq;

          fence = container_of(wait, struct radeon_fence, fence_wake);

          /*
           * We cannot use radeon_fence_process here because we're already
           * in the waitqueue, in a call from wake_up_all.
           */
          seq = atomic64_read(&fence->rdev->fence_drv[fence->ring].last_seq);
          if (seq >= fence->seq) {
                    int ret = dma_fence_signal_locked(&fence->base);

                    if (!ret)
                              DMA_FENCE_TRACE(&fence->base, "signaled from irq context\n");
                    else
                              DMA_FENCE_TRACE(&fence->base, "was already signaled\n");

                    radeon_irq_kms_sw_irq_put(fence->rdev, fence->ring);
                    __remove_wait_queue(&fence->rdev->fence_queue, &fence->fence_wake);
                    dma_fence_put(&fence->base);
          } else
                    DMA_FENCE_TRACE(&fence->base, "pending\n");
          return 0;
}

/**
 * radeon_fence_activity - check for fence activity
 *
 * @rdev: radeon_device pointer
 * @ring: ring index the fence is associated with
 *
 * 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 radeon_fence_activity(struct radeon_device *rdev, int 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 radeon_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 radeon_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(&rdev->fence_drv[ring].last_seq);
          do {
                    last_emitted = rdev->fence_drv[ring].sync_seq[ring];
                    seq = radeon_fence_read(rdev, 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(&rdev->fence_drv[ring].last_seq, seq) > seq);

          if (seq < last_emitted)
                    radeon_fence_schedule_check(rdev, ring);

          return wake;
}

/**
 * radeon_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 radeon_fence_check_lockup(struct work_struct *work)
{
          struct radeon_fence_driver *fence_drv;
          struct radeon_device *rdev;
          int ring;

          fence_drv = container_of(work, struct radeon_fence_driver,
                                         lockup_work.work);
          rdev = fence_drv->rdev;
          ring = fence_drv - &rdev->fence_drv[0];

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

          if (fence_drv->delayed_irq && rdev->ddev->irq_enabled) {
                    unsigned long irqflags;

                    fence_drv->delayed_irq = false;
                    spin_lock_irqsave(&rdev->irq.lock, irqflags);
                    radeon_irq_set(rdev);
                    spin_unlock_irqrestore(&rdev->irq.lock, irqflags);
          }

          if (radeon_fence_activity(rdev, ring))
                    wake_up_all(&rdev->fence_queue);

          else if (radeon_ring_is_lockup(rdev, ring, &rdev->ring[ring])) {

                    /* good news we believe it's a lockup */
                    dev_warn(rdev->dev, "GPU lockup (current fence id "
                               "0x%016lx last fence id 0x%016lx on ring %d)\n",
                               (uint64_t)atomic64_read(&fence_drv->last_seq),
                               fence_drv->sync_seq[ring], ring);

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

/**
 * radeon_fence_process - process a fence
 *
 * @rdev: radeon_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 radeon_fence_process(struct radeon_device *rdev, int ring)
{
          if (radeon_fence_activity(rdev, ring))
                    wake_up_all(&rdev->fence_queue);
}

/**
 * radeon_fence_seq_signaled - check if a fence sequence number has signaled
 *
 * @rdev: radeon device pointer
 * @seq: sequence number
 * @ring: ring index the fence is associated with
 *
 * 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
 * radeon_fence_signaled().
 */
static bool radeon_fence_seq_signaled(struct radeon_device *rdev,
                                              u64 seq, unsigned ring)
{
          if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) {
                    return true;
          }
          /* poll new last sequence at least once */
          radeon_fence_process(rdev, ring);
          if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) {
                    return true;
          }
          return false;
}

static bool radeon_fence_is_signaled(struct dma_fence *f)
{
          struct radeon_fence *fence = to_radeon_fence(f);
          struct radeon_device *rdev = fence->rdev;
          unsigned ring = fence->ring;
          u64 seq = fence->seq;

          if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) {
                    return true;
          }

          if (down_read_trylock(&rdev->exclusive_lock)) {
                    radeon_fence_process(rdev, ring);
                    up_read(&rdev->exclusive_lock);

                    if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) {
                              return true;
                    }
          }
          return false;
}

/**
 * radeon_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 radeon_fence_enable_signaling(struct dma_fence *f)
{
          struct radeon_fence *fence = to_radeon_fence(f);
          struct radeon_device *rdev = fence->rdev;

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

          if (down_read_trylock(&rdev->exclusive_lock)) {
                    radeon_irq_kms_sw_irq_get(rdev, fence->ring);

                    if (radeon_fence_activity(rdev, fence->ring))
                              wake_up_all_locked(&rdev->fence_queue);

                    /* did fence get signaled after we enabled the sw irq? */
                    if (atomic64_read(&rdev->fence_drv[fence->ring].last_seq) >= fence->seq) {
                              radeon_irq_kms_sw_irq_put(rdev, fence->ring);
                              up_read(&rdev->exclusive_lock);
                              return false;
                    }

                    up_read(&rdev->exclusive_lock);
          } else {
                    /* we're probably in a lockup, lets not fiddle too much */
                    if (radeon_irq_kms_sw_irq_get_delayed(rdev, fence->ring))
                              rdev->fence_drv[fence->ring].delayed_irq = true;
                    radeon_fence_schedule_check(rdev, fence->ring);
          }

          fence->fence_wake.flags = 0;
          fence->fence_wake.private = NULL;
          fence->fence_wake.func = radeon_fence_check_signaled;
          __add_wait_queue(&rdev->fence_queue, &fence->fence_wake);
          dma_fence_get(f);

          DMA_FENCE_TRACE(&fence->base, "armed on ring %i!\n", fence->ring);
          return true;
}

/**
 * radeon_fence_signaled - check if a fence has signaled
 *
 * @fence: radeon 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 radeon_fence_signaled(struct radeon_fence *fence)
{
          if (!fence)
                    return true;

          if (radeon_fence_seq_signaled(fence->rdev, fence->seq, fence->ring)) {
                    int ret;

                    ret = dma_fence_signal(&fence->base);
                    if (!ret)
                              DMA_FENCE_TRACE(&fence->base, "signaled from radeon_fence_signaled\n");
                    return true;
          }
          return false;
}

/**
 * radeon_fence_any_seq_signaled - check if any sequence number is signaled
 *
 * @rdev: radeon 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 radeon_fence_wait_seq.
 */
static bool radeon_fence_any_seq_signaled(struct radeon_device *rdev, u64 *seq)
{
          unsigned i;

          for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                    if (seq[i] && radeon_fence_seq_signaled(rdev, seq[i], i))
                              return true;
          }
          return false;
}

/**
 * radeon_fence_wait_seq_timeout - wait for a specific sequence numbers
 *
 * @rdev: radeon 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 radeon_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 radeon_fence_wait_seq_timeout(struct radeon_device *rdev,
                                                    u64 *target_seq, bool intr,
                                                    long timeout)
{
          long r;
          int i;

          if (radeon_fence_any_seq_signaled(rdev, target_seq))
                    return timeout;

          /* enable IRQs and tracing */
          for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                    if (!target_seq[i])
                              continue;

                    trace_radeon_fence_wait_begin(rdev->ddev, i, target_seq[i]);
                    radeon_irq_kms_sw_irq_get(rdev, i);
          }

          if (intr) {
                    r = wait_event_interruptible_timeout(rdev->fence_queue, (
                              radeon_fence_any_seq_signaled(rdev, target_seq)
                               || rdev->needs_reset), timeout);
          } else {
                    r = wait_event_timeout(rdev->fence_queue, (
                              radeon_fence_any_seq_signaled(rdev, target_seq)
                               || rdev->needs_reset), timeout);
          }

          if (rdev->needs_reset)
                    r = -EDEADLK;

          for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                    if (!target_seq[i])
                              continue;

                    radeon_irq_kms_sw_irq_put(rdev, i);
                    trace_radeon_fence_wait_end(rdev->ddev, i, target_seq[i]);
          }

          return r;
}

/**
 * radeon_fence_wait_timeout - wait for a fence to signal with timeout
 *
 * @fence: radeon fence object
 * @intr: use interruptible 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.
 * @timeout: maximum time to wait, or MAX_SCHEDULE_TIMEOUT for infinite wait
 * Returns remaining time if the sequence number has passed, 0 when
 * the wait timeout, or an error for all other cases.
 */
long radeon_fence_wait_timeout(struct radeon_fence *fence, bool intr, long timeout)
{
          u64 seq[RADEON_NUM_RINGS] = {};
          long r;
          int r_sig;

          /*
           * This function should not be called on !radeon fences.
           * If this is the case, it would mean this function can
           * also be called on radeon fences belonging to another card.
           * exclusive_lock is not held in that case.
           */
          if (WARN_ON_ONCE(!to_radeon_fence(&fence->base)))
                    return dma_fence_wait(&fence->base, intr);

          seq[fence->ring] = fence->seq;
          r = radeon_fence_wait_seq_timeout(fence->rdev, seq, intr, timeout);
          if (r <= 0) {
                    return r;
          }

          r_sig = dma_fence_signal(&fence->base);
          if (!r_sig)
                    DMA_FENCE_TRACE(&fence->base, "signaled from fence_wait\n");
          return r;
}

/**
 * radeon_fence_wait - wait for a fence to signal
 *
 * @fence: radeon fence object
 * @intr: use interruptible 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 radeon_fence_wait(struct radeon_fence *fence, bool intr)
{
          long r = radeon_fence_wait_timeout(fence, intr, MAX_SCHEDULE_TIMEOUT);
          if (r > 0) {
                    return 0;
          } else {
                    return r;
          }
}

/**
 * radeon_fence_wait_any - wait for a fence to signal on any ring
 *
 * @rdev: radeon device pointer
 * @fences: radeon 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 radeon_fence_wait_any(struct radeon_device *rdev,
                                struct radeon_fence **fences,
                                bool intr)
{
          u64 seq[RADEON_NUM_RINGS];
          unsigned i, num_rings = 0;
          long r;

          for (i = 0; i < RADEON_NUM_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 = radeon_fence_wait_seq_timeout(rdev, seq, intr, MAX_SCHEDULE_TIMEOUT);
          if (r < 0) {
                    return r;
          }
          return 0;
}

/**
 * radeon_fence_wait_next - wait for the next fence to signal
 *
 * @rdev: radeon 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 radeon_fence_wait_next(struct radeon_device *rdev, int ring)
{
          u64 seq[RADEON_NUM_RINGS] = {};
          long r;

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

/**
 * radeon_fence_wait_empty - wait for all fences to signal
 *
 * @rdev: radeon 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 radeon_fence_wait_empty(struct radeon_device *rdev, int ring)
{
          u64 seq[RADEON_NUM_RINGS] = {};
          long r;

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

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

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

/**
 * radeon_fence_ref - take a ref on a fence
 *
 * @fence: radeon fence object
 *
 * Take a reference on a fence (all asics).
 * Returns the fence.
 */
struct radeon_fence *radeon_fence_ref(struct radeon_fence *fence)
{
          dma_fence_get(&fence->base);
          return fence;
}

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

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

/**
 * radeon_fence_count_emitted - get the count of emitted fences
 *
 * @rdev: radeon device pointer
 * @ring: ring index 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 radeon_fence_count_emitted(struct radeon_device *rdev, int 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.
           */
          radeon_fence_process(rdev, ring);
          emitted = rdev->fence_drv[ring].sync_seq[ring]
                    - atomic64_read(&rdev->fence_drv[ring].last_seq);
          /* to avoid 32bits warp around */
          if (emitted > 0x10000000) {
                    emitted = 0x10000000;
          }
          return (unsigned)emitted;
}

/**
 * radeon_fence_need_sync - do we need a semaphore
 *
 * @fence: radeon 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 radeon_fence_need_sync(struct radeon_fence *fence, int dst_ring)
{
          struct radeon_fence_driver *fdrv;

          if (!fence) {
                    return false;
          }

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

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

          return true;
}

/**
 * radeon_fence_note_sync - record the sync point
 *
 * @fence: radeon 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 radeon_fence_note_sync(struct radeon_fence *fence, int dst_ring)
{
          struct radeon_fence_driver *dst, *src;
          unsigned i;

          if (!fence) {
                    return;
          }

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

          /* we are protected by the ring mutex */
          src = &fence->rdev->fence_drv[fence->ring];
          dst = &fence->rdev->fence_drv[dst_ring];
          for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                    if (i == dst_ring) {
                              continue;
                    }
                    dst->sync_seq[i] = max(dst->sync_seq[i], src->sync_seq[i]);
          }
}

/**
 * radeon_fence_driver_start_ring - make the fence driver
 * ready for use on the requested ring.
 *
 * @rdev: radeon device pointer
 * @ring: ring index to start the fence driver on
 *
 * 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 radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring)
{
          uint64_t index;
          int r;

          radeon_scratch_free(rdev, rdev->fence_drv[ring].scratch_reg);
          if (rdev->wb.use_event || !radeon_ring_supports_scratch_reg(rdev, &rdev->ring[ring])) {
                    rdev->fence_drv[ring].scratch_reg = 0;
                    if (ring != R600_RING_TYPE_UVD_INDEX) {
                              index = R600_WB_EVENT_OFFSET + ring * 4;
                              rdev->fence_drv[ring].cpu_addr = &rdev->wb.wb[index/4];
                              rdev->fence_drv[ring].gpu_addr = rdev->wb.gpu_addr +
                                                                       index;

                    } else {
                              /* put fence directly behind firmware */
                              index = ALIGN(rdev->uvd_fw->datasize, 8);
                              rdev->fence_drv[ring].cpu_addr = (void*)((uint8_t*)rdev->uvd.cpu_addr + index);
                              rdev->fence_drv[ring].gpu_addr = rdev->uvd.gpu_addr + index;
                    }

          } else {
                    r = radeon_scratch_get(rdev, &rdev->fence_drv[ring].scratch_reg);
                    if (r) {
                              dev_err(rdev->dev, "fence failed to get scratch register\n");
                              return r;
                    }
                    index = RADEON_WB_SCRATCH_OFFSET +
                              rdev->fence_drv[ring].scratch_reg -
                              rdev->scratch.reg_base;
                    rdev->fence_drv[ring].cpu_addr = &rdev->wb.wb[index/4];
                    rdev->fence_drv[ring].gpu_addr = rdev->wb.gpu_addr + index;
          }
          radeon_fence_write(rdev, atomic64_read(&rdev->fence_drv[ring].last_seq), ring);
          rdev->fence_drv[ring].initialized = true;
          dev_info(rdev->dev, "fence driver on ring %d use gpu addr 0x%016lx and cpu addr 0x%p\n",
                     ring, rdev->fence_drv[ring].gpu_addr, rdev->fence_drv[ring].cpu_addr);
          return 0;
}

/**
 * radeon_fence_driver_init_ring - init the fence driver
 * for the requested ring.
 *
 * @rdev: radeon device pointer
 * @ring: ring index to start the fence driver on
 *
 * Init the fence driver for the requested ring (all asics).
 * Helper function for radeon_fence_driver_init().
 */
static void radeon_fence_driver_init_ring(struct radeon_device *rdev, int ring)
{
          int i;

          rdev->fence_drv[ring].scratch_reg = -1;
          rdev->fence_drv[ring].cpu_addr = NULL;
          rdev->fence_drv[ring].gpu_addr = 0;
          for (i = 0; i < RADEON_NUM_RINGS; ++i)
                    rdev->fence_drv[ring].sync_seq[i] = 0;
          atomic64_set(&rdev->fence_drv[ring].last_seq, 0);
          rdev->fence_drv[ring].initialized = false;
          INIT_DELAYED_WORK(&rdev->fence_drv[ring].lockup_work,
                                radeon_fence_check_lockup);
          rdev->fence_drv[ring].rdev = rdev;
}

/**
 * radeon_fence_driver_init - init the fence driver
 * for all possible rings.
 *
 * @rdev: radeon 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
 * radeon_fence_driver_start_ring().
 * Returns 0 for success.
 */
int radeon_fence_driver_init(struct radeon_device *rdev)
{
          int ring;

          init_waitqueue_head(&rdev->fence_queue);
          for (ring = 0; ring < RADEON_NUM_RINGS; ring++) {
                    radeon_fence_driver_init_ring(rdev, ring);
          }
          if (radeon_debugfs_fence_init(rdev)) {
                    dev_err(rdev->dev, "fence debugfs file creation failed\n");
          }
          return 0;
}

/**
 * radeon_fence_driver_fini - tear down the fence driver
 * for all possible rings.
 *
 * @rdev: radeon device pointer
 *
 * Tear down the fence driver for all possible rings (all asics).
 */
void radeon_fence_driver_fini(struct radeon_device *rdev)
{
          int ring, r;

          mutex_lock(&rdev->ring_lock);
          for (ring = 0; ring < RADEON_NUM_RINGS; ring++) {
                    if (!rdev->fence_drv[ring].initialized)
                              continue;
                    r = radeon_fence_wait_empty(rdev, ring);
                    if (r) {
                              /* no need to trigger GPU reset as we are unloading */
                              radeon_fence_driver_force_completion(rdev, ring);
                    }
                    cancel_delayed_work_sync(&rdev->fence_drv[ring].lockup_work);
                    wake_up_all(&rdev->fence_queue);
                    radeon_scratch_free(rdev, rdev->fence_drv[ring].scratch_reg);
                    rdev->fence_drv[ring].initialized = false;
          }
          mutex_unlock(&rdev->ring_lock);
}

/**
 * radeon_fence_driver_force_completion - force all fence waiter to complete
 *
 * @rdev: radeon device pointer
 * @ring: the ring to complete
 *
 * In case of GPU reset failure make sure no process keep waiting on fence
 * that will never complete.
 */
void radeon_fence_driver_force_completion(struct radeon_device *rdev, int ring)
{
          if (rdev->fence_drv[ring].initialized) {
                    radeon_fence_write(rdev, rdev->fence_drv[ring].sync_seq[ring], ring);
                    cancel_delayed_work_sync(&rdev->fence_drv[ring].lockup_work);
          }
}


/*
 * Fence debugfs
 */
#if defined(CONFIG_DEBUG_FS)
static int radeon_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 radeon_device *rdev = dev->dev_private;
          int i, j;

          for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                    if (!rdev->fence_drv[i].initialized)
                              continue;

                    radeon_fence_process(rdev, i);

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

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

/**
 * radeon_debugfs_gpu_reset - manually trigger a gpu reset
 *
 * Manually trigger a gpu reset at the next fence wait.
 */
static int radeon_debugfs_gpu_reset(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 radeon_device *rdev = dev->dev_private;

          down_read(&rdev->exclusive_lock);
          seq_printf(m, "%d\n", rdev->needs_reset);
          rdev->needs_reset = true;
          wake_up_all(&rdev->fence_queue);
          up_read(&rdev->exclusive_lock);

          return 0;
}

static struct drm_info_list radeon_debugfs_fence_list[] = {
          {"radeon_fence_info", &radeon_debugfs_fence_info, 0, NULL},
          {"radeon_gpu_reset", &radeon_debugfs_gpu_reset, 0, NULL}
};
#endif

int radeon_debugfs_fence_init(struct radeon_device *rdev)
{
#if defined(CONFIG_DEBUG_FS)
          return radeon_debugfs_add_files(rdev, radeon_debugfs_fence_list, 2);
#else
          return 0;
#endif
}

static const char *radeon_fence_get_driver_name(struct dma_fence *fence)
{
          return "radeon";
}

static const char *radeon_fence_get_timeline_name(struct dma_fence *f)
{
          struct radeon_fence *fence = to_radeon_fence(f);
          switch (fence->ring) {
          case RADEON_RING_TYPE_GFX_INDEX: return "radeon.gfx";
          case CAYMAN_RING_TYPE_CP1_INDEX: return "radeon.cp1";
          case CAYMAN_RING_TYPE_CP2_INDEX: return "radeon.cp2";
          case R600_RING_TYPE_DMA_INDEX: return "radeon.dma";
          case CAYMAN_RING_TYPE_DMA1_INDEX: return "radeon.dma1";
          case R600_RING_TYPE_UVD_INDEX: return "radeon.uvd";
          case TN_RING_TYPE_VCE1_INDEX: return "radeon.vce1";
          case TN_RING_TYPE_VCE2_INDEX: return "radeon.vce2";
          default: WARN_ON_ONCE(1); return "radeon.unk";
          }
}

static inline bool radeon_test_signaled(struct radeon_fence *fence)
{
          return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags);
}

struct radeon_wait_cb {
          struct dma_fence_cb base;
          struct task_struct *task;
};

static void
radeon_fence_wait_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
{
          struct radeon_wait_cb *wait =
                    container_of(cb, struct radeon_wait_cb, base);

          wake_up_process(wait->task);
}

static signed long radeon_fence_default_wait(struct dma_fence *f, bool intr,
                                                       signed long t)
{
          struct radeon_fence *fence = to_radeon_fence(f);
          struct radeon_device *rdev = fence->rdev;
          struct radeon_wait_cb cb;

          cb.task = current;

          if (dma_fence_add_callback(f, &cb.base, radeon_fence_wait_cb))
                    return t;

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

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

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

                    t = schedule_timeout(t);

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

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

          return t;
}

const struct dma_fence_ops radeon_fence_ops = {
          .get_driver_name = radeon_fence_get_driver_name,
          .get_timeline_name = radeon_fence_get_timeline_name,
          .enable_signaling = radeon_fence_enable_signaling,
          .signaled = radeon_fence_is_signaled,
          .wait = radeon_fence_default_wait,
          .release = NULL,
};