drm/crc: Cleanup crtc_crc_open function

This patch make changes to allocate crc-entries buffer before
enabling CRC generation.
It moves all the failure check early in the function before setting
the source or memory allocation.
Now set_crc_source takes only two variable inputs, values_cnt we
already gets as part of verify_crc_source.

Changes since V1:
- refactor code to use single spin lock
Changes since V2:
- rebase
Changes since V3:
- rebase on top of VKMS driver

Signed-off-by: Mahesh Kumar <[e-mail]>
Cc: [e-mail]
Cc: Laurent Pinchart <[e-mail]>
Cc: Haneen Mohammed <[e-mail]>
Reviewed-by: Maarten Lankhorst <[e-mail]>
Acked-by: Leo Li <[e-mail]> (V2)
Reviewed-by: Laurent Pinchart <[e-mail]> (V3)
Signed-off-by: Rodrigo Vivi <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

···
 
 /* amdgpu_dm_crc.c */
 #ifdef CONFIG_DEBUG_FS
-int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name,
-				  size_t *values_cnt);
+int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name);
 int amdgpu_dm_crtc_verify_crc_source(struct drm_crtc *crtc,
 				     const char *src_name,
 				     size_t *values_cnt);

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c

···
 	return 0;
 }
 
-int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name,
-			   size_t *values_cnt)
+int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name)
 {
 	struct dm_crtc_state *crtc_state = to_dm_crtc_state(crtc->state);
 	struct dc_stream_state *stream_state = crtc_state->stream;
···
 			return -EINVAL;
 	}
 
-	*values_cnt = 3;
 	/* Reset crc_skipped on dm state */
 	crtc_state->crc_skip_count = 0;
 	return 0;

drivers/gpu/drm/drm_debugfs_crc.c

···
 	if (source[len] == '\n')
 		source[len] = '\0';
 
-	if (crtc->funcs->verify_crc_source) {
-		ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);
-		if (ret)
-			return ret;
-	}
+	ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);
+	if (ret)
+		return ret;
 
 	spin_lock_irq(&crc->lock);
 
···
 			return ret;
 	}
 
-	spin_lock_irq(&crc->lock);
-	if (!crc->opened)
-		crc->opened = true;
-	else
-		ret = -EBUSY;
-	spin_unlock_irq(&crc->lock);
-
+	ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt);
 	if (ret)
 		return ret;
 
-	ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt);
+	if (WARN_ON(values_cnt > DRM_MAX_CRC_NR))
+		return -EINVAL;
+
+	if (WARN_ON(values_cnt == 0))
+		return -EINVAL;
+
+	entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
+	if (!entries)
+		return -ENOMEM;
+
+	spin_lock_irq(&crc->lock);
+	if (!crc->opened) {
+		crc->opened = true;
+		crc->entries = entries;
+		crc->values_cnt = values_cnt;
+	} else {
+		ret = -EBUSY;
+	}
+	spin_unlock_irq(&crc->lock);
+
+	if (ret) {
+		kfree(entries);
+		return ret;
+	}
+
+	ret = crtc->funcs->set_crc_source(crtc, crc->source);
 	if (ret)
 		goto err;
 
-	if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) {
-		ret = -EINVAL;
-		goto err_disable;
-	}
-
-	if (WARN_ON(values_cnt == 0)) {
-		ret = -EINVAL;
-		goto err_disable;
-	}
-
-	entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
-	if (!entries) {
-		ret = -ENOMEM;
-		goto err_disable;
-	}
-
 	spin_lock_irq(&crc->lock);
-	crc->entries = entries;
-	crc->values_cnt = values_cnt;
-
 	/*
 	 * Only return once we got a first frame, so userspace doesn't have to
 	 * guess when this particular piece of HW will be ready to start
···
 	return 0;
 
 err_disable:
-	crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
+	crtc->funcs->set_crc_source(crtc, NULL);
 err:
 	spin_lock_irq(&crc->lock);
 	crtc_crc_cleanup(crc);
···
 {
 	struct drm_crtc *crtc = filep->f_inode->i_private;
 	struct drm_crtc_crc *crc = &crtc->crc;
-	size_t values_cnt;
 
-	crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
+	crtc->funcs->set_crc_source(crtc, NULL);
 
 	spin_lock_irq(&crc->lock);
 	crtc_crc_cleanup(crc);
···
 {
 	struct dentry *crc_ent, *ent;
 
-	if (!crtc->funcs->set_crc_source)
+	if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)
 		return 0;
 
 	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);

drivers/gpu/drm/i915/intel_drv.h

···
 /* intel_pipe_crc.c */
 int intel_pipe_crc_create(struct drm_minor *minor);
 #ifdef CONFIG_DEBUG_FS
-int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
-			      size_t *values_cnt);
+int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name);
 int intel_crtc_verify_crc_source(struct drm_crtc *crtc,
 				 const char *source_name, size_t *values_cnt);
 const char *const *intel_crtc_get_crc_sources(struct drm_crtc *crtc,

drivers/gpu/drm/i915/intel_pipe_crc.c

···
 	return -EINVAL;
 }
 
-int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
-			      size_t *values_cnt)
+int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->dev);
 	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[crtc->index];
···
 	}
 
 	pipe_crc->skipped = 0;
-	*values_cnt = 5;
 
 out:
 	intel_display_power_put(dev_priv, power_domain);

drivers/gpu/drm/rcar-du/rcar_du_crtc.c

···
 }
 
 static int rcar_du_crtc_set_crc_source(struct drm_crtc *crtc,
-				       const char *source_name,
-				       size_t *values_cnt)
+				       const char *source_name)
 {
 	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
 	struct drm_modeset_acquire_ctx ctx;
···
 		return ret;
 
 	index = ret;
-	*values_cnt = 1;
 
 	/* Perform an atomic commit to set the CRC source. */
 	drm_modeset_acquire_init(&ctx, 0);

drivers/gpu/drm/rockchip/rockchip_drm_vop.c

···
 }
 
 static int vop_crtc_set_crc_source(struct drm_crtc *crtc,
-				   const char *source_name, size_t *values_cnt)
+				   const char *source_name)
 {
 	struct vop *vop = to_vop(crtc);
 	struct drm_connector *connector;
···
 	connector = vop_get_edp_connector(vop);
 	if (!connector)
 		return -EINVAL;
-
-	*values_cnt = 3;
 
 	if (source_name && strcmp(source_name, "auto") == 0)
 		ret = analogix_dp_start_crc(connector);
···
 
 #else
 static int vop_crtc_set_crc_source(struct drm_crtc *crtc,
-				   const char *source_name, size_t *values_cnt)
+				   const char *source_name)
 {
 	return -ENODEV;
 }

drivers/gpu/drm/vkms/vkms_crc.c

···
 	return 0;
 }
 
-int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name,
-			size_t *values_cnt)
+int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name)
 {
 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 	bool enabled = false;
···
 	int ret = 0;
 
 	ret = vkms_crc_parse_source(src_name, &enabled);
-
-	*values_cnt = 1;
 
 	/* make sure nothing is scheduled on crtc workq */
 	flush_workqueue(out->crc_workq);

drivers/gpu/drm/vkms/vkms_drv.h

···
 void vkms_gem_vunmap(struct drm_gem_object *obj);
 
 /* CRC Support */
-int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name,
-			size_t *values_cnt);
+int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name);
 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *source_name,
 			   size_t *values_cnt);
 void vkms_crc_work_handle(struct work_struct *work);

include/drm/drm_crtc.h

···
 	 *
 	 * 0 on success or a negative error code on failure.
 	 */
-	int (*set_crc_source)(struct drm_crtc *crtc, const char *source,
-			      size_t *values_cnt);
+	int (*set_crc_source)(struct drm_crtc *crtc, const char *source);
 	/**
 	 * @verify_crc_source:
 	 *