drm/amdgpu: add new IOCTL for usermode queue

This patch adds:
- A new IOCTL function to create and destroy
- A new structure to keep all the user queue data in one place.
- A function to generate unique index for the queue.

V1: Worked on review comments from RFC patch series:
  - Alex: Keep a list of queues, instead of single queue per process.
  - Christian: Use the queue manager instead of global ptrs,
           Don't keep the queue structure in amdgpu_ctx

V2: Worked on review comments:
 - Christian:
   - Formatting of text
   - There is no need for queuing of userqueues, with idr in place
 - Alex:
   - Remove use_doorbell, its unnecessary
   - Reuse amdgpu_mqd_props for saving mqd fields

 - Code formatting and re-arrangement

V3:
 - Integration with doorbell manager

V4:
 - Accommodate MQD union related changes in UAPI (Alex)
 - Do not set the queue size twice (Bas)

V5:
 - Remove wrapper functions for queue indexing (Christian)
 - Do not save the queue id/idr in queue itself (Christian)
 - Move the idr allocation in the IP independent generic space
  (Christian)

V6:
 - Check the validity of input IP type (Christian)

V7:
 - Move uq_func from uq_mgr to adev (Alex)
 - Add missing free(queue) for error cases (Yifan)

V9:
 - Rebase

V10: Addressed review comments from Christian, and added R-B:
 - Do not initialize the local variable
 - Convert DRM_ERROR to DEBUG.

V11:
  - check the input flags to be zero (Alex)

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

drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c

@@ -23,6 +23,126 @@
  */
 
 #include "amdgpu.h"
+#include "amdgpu_vm.h"
+#include "amdgpu_userqueue.h"
+
+static struct amdgpu_usermode_queue *
+amdgpu_userqueue_find(struct amdgpu_userq_mgr *uq_mgr, int qid)
+{
+	return idr_find(&uq_mgr->userq_idr, qid);
+}
+
+static int
+amdgpu_userqueue_destroy(struct drm_file *filp, int queue_id)
+{
+	struct amdgpu_fpriv *fpriv = filp->driver_priv;
+	struct amdgpu_userq_mgr *uq_mgr = &fpriv->userq_mgr;
+	struct amdgpu_device *adev = uq_mgr->adev;
+	const struct amdgpu_userq_funcs *uq_funcs;
+	struct amdgpu_usermode_queue *queue;
+
+	mutex_lock(&uq_mgr->userq_mutex);
+
+	queue = amdgpu_userqueue_find(uq_mgr, queue_id);
+	if (!queue) {
+		DRM_DEBUG_DRIVER("Invalid queue id to destroy\n");
+		mutex_unlock(&uq_mgr->userq_mutex);
+		return -EINVAL;
+	}
+
+	uq_funcs = adev->userq_funcs[queue->queue_type];
+	uq_funcs->mqd_destroy(uq_mgr, queue);
+	idr_remove(&uq_mgr->userq_idr, queue_id);
+	kfree(queue);
+
+	mutex_unlock(&uq_mgr->userq_mutex);
+	return 0;
+}
+
+static int
+amdgpu_userqueue_create(struct drm_file *filp, union drm_amdgpu_userq *args)
+{
+	struct amdgpu_fpriv *fpriv = filp->driver_priv;
+	struct amdgpu_userq_mgr *uq_mgr = &fpriv->userq_mgr;
+	struct amdgpu_device *adev = uq_mgr->adev;
+	const struct amdgpu_userq_funcs *uq_funcs;
+	struct amdgpu_usermode_queue *queue;
+	int qid, r = 0;
+
+	if (args->in.flags) {
+		DRM_ERROR("Usermode queue flags not supported yet\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&uq_mgr->userq_mutex);
+
+	uq_funcs = adev->userq_funcs[args->in.ip_type];
+	if (!uq_funcs) {
+		DRM_ERROR("Usermode queue is not supported for this IP (%u)\n", args->in.ip_type);
+		r = -EINVAL;
+		goto unlock;
+	}
+
+	queue = kzalloc(sizeof(struct amdgpu_usermode_queue), GFP_KERNEL);
+	if (!queue) {
+		DRM_ERROR("Failed to allocate memory for queue\n");
+		r = -ENOMEM;
+		goto unlock;
+	}
+	queue->doorbell_handle = args->in.doorbell_handle;
+	queue->doorbell_index = args->in.doorbell_offset;
+	queue->queue_type = args->in.ip_type;
+	queue->flags = args->in.flags;
+	queue->vm = &fpriv->vm;
+
+	r = uq_funcs->mqd_create(uq_mgr, &args->in, queue);
+	if (r) {
+		DRM_ERROR("Failed to create Queue\n");
+		kfree(queue);
+		goto unlock;
+	}
+
+	qid = idr_alloc(&uq_mgr->userq_idr, queue, 1, AMDGPU_MAX_USERQ_COUNT, GFP_KERNEL);
+	if (qid < 0) {
+		DRM_ERROR("Failed to allocate a queue id\n");
+		uq_funcs->mqd_destroy(uq_mgr, queue);
+		kfree(queue);
+		r = -ENOMEM;
+		goto unlock;
+	}
+	args->out.queue_id = qid;
+
+unlock:
+	mutex_unlock(&uq_mgr->userq_mutex);
+	return r;
+}
+
+int amdgpu_userq_ioctl(struct drm_device *dev, void *data,
+		       struct drm_file *filp)
+{
+	union drm_amdgpu_userq *args = data;
+	int r;
+
+	switch (args->in.op) {
+	case AMDGPU_USERQ_OP_CREATE:
+		r = amdgpu_userqueue_create(filp, args);
+		if (r)
+			DRM_ERROR("Failed to create usermode queue\n");
+		break;
+
+	case AMDGPU_USERQ_OP_FREE:
+		r = amdgpu_userqueue_destroy(filp, args->in.queue_id);
+		if (r)
+			DRM_ERROR("Failed to destroy usermode queue\n");
+		break;
+
+	default:
+		DRM_DEBUG_DRIVER("Invalid user queue op specified: %d\n", args->in.op);
+		return -EINVAL;
+	}
+
+	return r;
+}
 
 int amdgpu_userq_mgr_init(struct amdgpu_userq_mgr *userq_mgr, struct amdgpu_device *adev)
 {