int scmi_protocol_device_request()

in arm_scmi/driver.c [1636:1745]

• 79 lines of code
• 11 McCabe index (conditional complexity)

int scmi_protocol_device_request(const struct scmi_device_id *id_table)
{
	int ret = 0;
	unsigned int id = 0;
	struct list_head *head, *phead = NULL;
	struct scmi_requested_dev *rdev;
	struct scmi_info *info;

	pr_debug("Requesting SCMI device (%s) for protocol %x\n",
		 id_table->name, id_table->protocol_id);

	/*
	 * Search for the matching protocol rdev list and then search
	 * of any existent equally named device...fails if any duplicate found.
	 */
	mutex_lock(&scmi_requested_devices_mtx);
	idr_for_each_entry(&scmi_requested_devices, head, id) {
		if (!phead) {
			/* A list found registered in the IDR is never empty */
			rdev = list_first_entry(head, struct scmi_requested_dev,
						node);
			if (rdev->id_table->protocol_id ==
			    id_table->protocol_id)
				phead = head;
		}
		list_for_each_entry(rdev, head, node) {
			if (!strcmp(rdev->id_table->name, id_table->name)) {
				pr_err("Ignoring duplicate request [%d] %s\n",
				       rdev->id_table->protocol_id,
				       rdev->id_table->name);
				ret = -EINVAL;
				goto out;
			}
		}
	}

	/*
	 * No duplicate found for requested id_table, so let's create a new
	 * requested device entry for this new valid request.
	 */
	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
	if (!rdev) {
		ret = -ENOMEM;
		goto out;
	}
	rdev->id_table = id_table;

	/*
	 * Append the new requested device table descriptor to the head of the
	 * related protocol list, eventually creating such head if not already
	 * there.
	 */
	if (!phead) {
		phead = kzalloc(sizeof(*phead), GFP_KERNEL);
		if (!phead) {
			kfree(rdev);
			ret = -ENOMEM;
			goto out;
		}
		INIT_LIST_HEAD(phead);

		ret = idr_alloc(&scmi_requested_devices, (void *)phead,
				id_table->protocol_id,
				id_table->protocol_id + 1, GFP_KERNEL);
		if (ret != id_table->protocol_id) {
			pr_err("Failed to save SCMI device - ret:%d\n", ret);
			kfree(rdev);
			kfree(phead);
			ret = -EINVAL;
			goto out;
		}
		ret = 0;
	}
	list_add(&rdev->node, phead);

	/*
	 * Now effectively create and initialize the requested device for every
	 * already initialized SCMI instance which has registered the requested
	 * protocol as a valid active one: i.e. defined in DT and supported by
	 * current platform FW.
	 */
	mutex_lock(&scmi_list_mutex);
	list_for_each_entry(info, &scmi_list, node) {
		struct device_node *child;

		child = idr_find(&info->active_protocols,
				 id_table->protocol_id);
		if (child) {
			struct scmi_device *sdev;

			sdev = scmi_get_protocol_device(child, info,
							id_table->protocol_id,
							id_table->name);
			/* Set handle if not already set: device existed */
			if (sdev && !sdev->handle)
				sdev->handle =
					scmi_handle_get_from_info_unlocked(info);
		} else {
			dev_err(info->dev,
				"Failed. SCMI protocol %d not active.\n",
				id_table->protocol_id);
		}
	}
	mutex_unlock(&scmi_list_mutex);

out:
	mutex_unlock(&scmi_requested_devices_mtx);

	return ret;
}