drm/amdgpu: suspend gfx userqueues

This patch adds suspend support for gfx userqueues. It typically does
the following:
- adds an enable_signaling function for the eviction fence, so that it
  can trigger the userqueue suspend,
- adds a delayed work to handle suspending of the eviction_fence
- adds a suspend function to handle suspending of userqueues which
  suspends all the queues under this userq manager and signals the
  eviction fence,
- adds a function to replace the old eviction fence with a new one and
  attach it to each of the objects,
- adds reference of userq manager in the eviction fence container so
  that it can be used in the suspend function.

V2: Addressed Christian's review comments:
    - schedule suspend work immediately

V4: Addressed Christian's review comments:
    - wait for pending uq fences before starting suspend, added
      queue->last_fence for the same
    - accommodate ev_fence_mgr into existing code
    - some bug fixes and NULL checks

V5: Addressed Christian's review comments (gitlab)
    - Wait for eviction fence to get signaled in destroy,
      don't signal it
    - Wait for eviction fence to get signaled in replace fence,
      don't signal it

V6: Addressed Christian's review comments
    - Do not destroy the old eviction fence until we have it replaced
    - Change the sequence of fence replacement sub-tasks
    - reusing the ev_fence delayed work for userqueue suspend as well
      (Shashank).

V7: Addressed Christian's review comments
    - give evf_mgr as argument (instead of fpriv) to replace_fence()
    - save ptr to evf_mgr in ev_fence (instead of uq_mgr)
    - modify suspend_all_queues logic to reflect error properly
    - remove the garbage drm_exec_lock section in wait_for_signal
    - grab the userqueue mutex before starting the wait for fence
    - remove the unrelated gobj check from signal_ioctl

V8: Added race condition fixes

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Acked-by: Christian Koenig <christian.koenig@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Arvind Yadav <arvind.yadav@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 127 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
index 056798e2b050..189afb872775 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
@@ -22,8 +22,12 @@
  *
  */
 #include <linux/sched.h>
+#include <drm/drm_exec.h>
 #include "amdgpu.h"
 
+#define work_to_evf_mgr(w, name) container_of(w, struct amdgpu_eviction_fence_mgr, name)
+#define evf_mgr_to_fpriv(e) container_of(e, struct amdgpu_fpriv, evf_mgr)
+
 static const char *
 amdgpu_eviction_fence_get_driver_name(struct dma_fence *fence)
 {
@@ -39,10 +43,131 @@ amdgpu_eviction_fence_get_timeline_name(struct dma_fence *f)
 	return ef->timeline_name;
 }
 
+int
+amdgpu_eviction_fence_replace_fence(struct amdgpu_eviction_fence_mgr *evf_mgr,
+				    struct drm_exec *exec)
+{
+	struct amdgpu_eviction_fence *old_ef, *new_ef;
+	struct drm_gem_object *obj;
+	unsigned long index;
+	int ret;
+
+	/*
+	 * Steps to replace eviction fence:
+	 * * lock all objects in exec (caller)
+	 * * create a new eviction fence
+	 * * update new eviction fence in evf_mgr
+	 * * attach the new eviction fence to BOs
+	 * * release the old fence
+	 * * unlock the objects (caller)
+	 */
+	new_ef = amdgpu_eviction_fence_create(evf_mgr);
+	if (!new_ef) {
+		DRM_ERROR("Failed to create new eviction fence\n");
+		return -ENOMEM;
+	}
+
+	/* Update the eviction fence now */
+	spin_lock(&evf_mgr->ev_fence_lock);
+	old_ef = evf_mgr->ev_fence;
+	evf_mgr->ev_fence = new_ef;
+	spin_unlock(&evf_mgr->ev_fence_lock);
+
+	/* Attach the new fence */
+	drm_exec_for_each_locked_object(exec, index, obj) {
+		struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+
+		if (!bo)
+			continue;
+		ret = amdgpu_eviction_fence_attach(evf_mgr, bo);
+		if (ret) {
+			DRM_ERROR("Failed to attch new eviction fence\n");
+			goto free_err;
+		}
+	}
+
+	/* Free old fence */
+	dma_fence_put(&old_ef->base);
+	return 0;
+
+free_err:
+	kfree(new_ef);
+	return ret;
+}
+
+static void
+amdgpu_eviction_fence_suspend_worker(struct work_struct *work)
+{
+	struct amdgpu_eviction_fence_mgr *evf_mgr = work_to_evf_mgr(work, suspend_work.work);
+	struct amdgpu_fpriv *fpriv = evf_mgr_to_fpriv(evf_mgr);
+	struct amdgpu_userq_mgr *uq_mgr = &fpriv->userq_mgr;
+	struct amdgpu_vm *vm = &fpriv->vm;
+	struct amdgpu_bo_va *bo_va;
+	struct drm_exec exec;
+	bool userq_active = amdgpu_userqueue_active(uq_mgr);
+	int ret;
+
+
+	/* For userqueues, the fence replacement happens in resume path */
+	if (userq_active) {
+		amdgpu_userqueue_suspend(uq_mgr);
+		return;
+	}
+
+	/* Signal old eviction fence */
+	amdgpu_eviction_fence_signal(evf_mgr);
+
+	/* Prepare the objects to replace eviction fence */
+	drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0);
+	drm_exec_until_all_locked(&exec) {
+		ret = amdgpu_vm_lock_pd(vm, &exec, 2);
+		drm_exec_retry_on_contention(&exec);
+		if (unlikely(ret))
+			goto unlock_drm;
+
+		/* Lock the done list */
+		list_for_each_entry(bo_va, &vm->done, base.vm_status) {
+			struct amdgpu_bo *bo = bo_va->base.bo;
+
+			if (!bo)
+				continue;
+
+			ret = drm_exec_lock_obj(&exec, &bo->tbo.base);
+			drm_exec_retry_on_contention(&exec);
+			if (unlikely(ret))
+				goto unlock_drm;
+		}
+	}
+
+	/* Replace old eviction fence with new one */
+	ret = amdgpu_eviction_fence_replace_fence(&fpriv->evf_mgr, &exec);
+	if (ret)
+		DRM_ERROR("Failed to replace eviction fence\n");
+
+unlock_drm:
+	drm_exec_fini(&exec);
+}
+
+static bool amdgpu_eviction_fence_enable_signaling(struct dma_fence *f)
+{
+	struct amdgpu_eviction_fence_mgr *evf_mgr;
+	struct amdgpu_eviction_fence *ev_fence;
+
+	if (!f)
+		return true;
+
+	ev_fence = to_ev_fence(f);
+	evf_mgr = ev_fence->evf_mgr;
+
+	schedule_delayed_work(&evf_mgr->suspend_work, 0);
+	return true;
+}
+
 static const struct dma_fence_ops amdgpu_eviction_fence_ops = {
 	.use_64bit_seqno = true,
 	.get_driver_name = amdgpu_eviction_fence_get_driver_name,
 	.get_timeline_name = amdgpu_eviction_fence_get_timeline_name,
+	.enable_signaling = amdgpu_eviction_fence_enable_signaling,
 };
 
 void amdgpu_eviction_fence_signal(struct amdgpu_eviction_fence_mgr *evf_mgr)
@@ -140,5 +265,7 @@ int amdgpu_eviction_fence_init(struct amdgpu_eviction_fence_mgr *evf_mgr)
 	spin_lock(&evf_mgr->ev_fence_lock);
 	evf_mgr->ev_fence = ev_fence;
 	spin_unlock(&evf_mgr->ev_fence_lock);
+
+	INIT_DELAYED_WORK(&evf_mgr->suspend_work, amdgpu_eviction_fence_suspend_worker);
 	return 0;
 }