accel/ivpu: Use lazy allocation for doorbell IDs

Reserve/allocate and free doorbells for command queues when needed
using xarray. This allows to avoid reserving a doorbell for
a contexts that never issues a job.
Signed-off-by: Wachowski, Karol <karol.wachowski@intel.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240214081305.290108-6-jacek.lawrynowicz@linux.intel.com

drivers/accel/ivpu/ivpu_drv.c

@@ -533,6 +533,7 @@ static int ivpu_dev_init(struct ivpu_device *vdev)
 	atomic64_set(&vdev->unique_id_counter, 0);
 	xa_init_flags(&vdev->context_xa, XA_FLAGS_ALLOC);
 	xa_init_flags(&vdev->submitted_jobs_xa, XA_FLAGS_ALLOC1);
+	xa_init_flags(&vdev->db_xa, XA_FLAGS_ALLOC1);
 	lockdep_set_class(&vdev->submitted_jobs_xa.xa_lock, &submitted_jobs_xa_lock_class_key);
 	INIT_LIST_HEAD(&vdev->bo_list);
 
@@ -606,6 +607,7 @@ static int ivpu_dev_init(struct ivpu_device *vdev)
 	if (IVPU_WA(d3hot_after_power_off))
 		pci_set_power_state(to_pci_dev(vdev->drm.dev), PCI_D3hot);
 err_xa_destroy:
+	xa_destroy(&vdev->db_xa);
 	xa_destroy(&vdev->submitted_jobs_xa);
 	xa_destroy(&vdev->context_xa);
 	return ret;
@@ -641,6 +643,8 @@ static void ivpu_dev_fini(struct ivpu_device *vdev)
 	ivpu_mmu_reserved_context_fini(vdev);
 	ivpu_mmu_global_context_fini(vdev);
 
+	drm_WARN_ON(&vdev->drm, !xa_empty(&vdev->db_xa));
+	xa_destroy(&vdev->db_xa);
 	drm_WARN_ON(&vdev->drm, !xa_empty(&vdev->submitted_jobs_xa));
 	xa_destroy(&vdev->submitted_jobs_xa);
 	drm_WARN_ON(&vdev->drm, !xa_empty(&vdev->context_xa));

drivers/accel/ivpu/ivpu_drv.h

@@ -36,6 +36,9 @@
 #define IVPU_USER_CONTEXT_MIN_SSID     2
 #define IVPU_USER_CONTEXT_MAX_SSID     (IVPU_USER_CONTEXT_MIN_SSID + 63)
 
+#define IVPU_MIN_DB 1
+#define IVPU_MAX_DB 255
+
 #define IVPU_NUM_ENGINES 2
 
 #define IVPU_PLATFORM_SILICON 0
@@ -119,6 +122,8 @@ struct ivpu_device {
 	struct xarray context_xa;
 	struct xa_limit context_xa_limit;
 
+	struct xarray db_xa;
+
 	struct mutex bo_list_lock; /* Protects bo_list */
 	struct list_head bo_list;
 

drivers/accel/ivpu/ivpu_job.c

@@ -30,19 +30,26 @@ static void ivpu_cmdq_ring_db(struct ivpu_device *vdev, struct ivpu_cmdq *cmdq)
 
 static struct ivpu_cmdq *ivpu_cmdq_alloc(struct ivpu_file_priv *file_priv, u16 engine)
 {
+	struct xa_limit db_xa_limit = {.max = IVPU_MAX_DB, .min = IVPU_MIN_DB};
 	struct ivpu_device *vdev = file_priv->vdev;
 	struct vpu_job_queue_header *jobq_header;
 	struct ivpu_cmdq *cmdq;
+	int ret;
 
 	cmdq = kzalloc(sizeof(*cmdq), GFP_KERNEL);
 	if (!cmdq)
 		return NULL;
 
+	ret = xa_alloc(&vdev->db_xa, &cmdq->db_id, NULL, db_xa_limit, GFP_KERNEL);
+	if (ret) {
+		ivpu_err(vdev, "Failed to allocate doorbell id: %d\n", ret);
+		goto err_free_cmdq;
+	}
+
 	cmdq->mem = ivpu_bo_alloc_internal(vdev, 0, SZ_4K, DRM_IVPU_BO_WC);
 	if (!cmdq->mem)
-		goto cmdq_free;
+		goto err_erase_xa;
 
-	cmdq->db_id = file_priv->ctx.id + engine * ivpu_get_context_count(vdev);
 	cmdq->entry_count = (u32)((ivpu_bo_size(cmdq->mem) - sizeof(struct vpu_job_queue_header)) /
 				  sizeof(struct vpu_job_queue_entry));
 
@@ -55,7 +62,9 @@ static struct ivpu_cmdq *ivpu_cmdq_alloc(struct ivpu_file_priv *file_priv, u16 e
 
 	return cmdq;
 
-cmdq_free:
+err_erase_xa:
+	xa_erase(&vdev->db_xa, cmdq->db_id);
+err_free_cmdq:
 	kfree(cmdq);
 	return NULL;
 }
@@ -66,6 +75,7 @@ static void ivpu_cmdq_free(struct ivpu_file_priv *file_priv, struct ivpu_cmdq *c
 		return;
 
 	ivpu_bo_free_internal(cmdq->mem);
+	xa_erase(&file_priv->vdev->db_xa, cmdq->db_id);
 	kfree(cmdq);
 }