disp: msm: sde: avoid sde debugfs register access based on HW ownership

Add VM ownership checks before accessing the HW through the debugfs
path in sde crtc/encoder/connector modules to avoid illegal access.

Change-Id: I4ff8f29353835d263beb2091bdeec40125addbf8
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>

msm/sde/sde_connector.c

@@ -1978,6 +1978,8 @@ static ssize_t _sde_debugfs_conn_cmd_tx_write(struct file *file,
 {
 	struct drm_connector *connector = file->private_data;
 	struct sde_connector *c_conn = NULL;
+	struct sde_vm_ops *vm_ops;
+	struct sde_kms *sde_kms;
 	char *input, *token, *input_copy, *input_dup = NULL;
 	const char *delim = " ";
 	char buffer[MAX_CMD_PAYLOAD_SIZE] = {0};
@@ -1988,9 +1990,14 @@ static ssize_t _sde_debugfs_conn_cmd_tx_write(struct file *file,
 		SDE_ERROR("invalid argument(s), conn %d\n", connector != NULL);
 		return -EINVAL;
 	}
-
 	c_conn = to_sde_connector(connector);
 
+	sde_kms = _sde_connector_get_kms(&c_conn->base);
+	if (!sde_kms) {
+		SDE_ERROR("invalid kms\n");
+		return -EINVAL;
+	}
+
 	if (!c_conn->ops.cmd_transfer) {
 		SDE_ERROR("no cmd transfer support for connector name %s\n",
 				c_conn->name);
@@ -2001,6 +2008,14 @@ static ssize_t _sde_debugfs_conn_cmd_tx_write(struct file *file,
 	if (!input)
 		return -ENOMEM;
 
+	vm_ops = sde_vm_get_ops(sde_kms);
+	sde_vm_lock(sde_kms);
+	if (vm_ops && vm_ops->vm_owns_hw && !vm_ops->vm_owns_hw(sde_kms)) {
+		SDE_DEBUG("op not supported due to HW unavailablity\n");
+		rc = -EOPNOTSUPP;
+		goto end;
+	}
+
 	if (copy_from_user(input, p, count)) {
 		SDE_ERROR("copy from user failed\n");
 		rc = -EFAULT;
@@ -2050,6 +2065,7 @@ static ssize_t _sde_debugfs_conn_cmd_tx_write(struct file *file,
 end1:
 	kfree(input_dup);
 end:
+	sde_vm_unlock(sde_kms);
 	kfree(input);
 	return rc;
 }