Function bus_helper_reset_prepare

freebsd/kern/subr_bus.c:3931–3962

* @brief Helper function for implementing BUS_RESET_PREPARE * * Bus can use this function to implement common operations of * detaching or suspending the children before the bus itself is * reset, and then save bus-unique state of children that must * persists around reset. * * @param dev The bus * #param flags DEVF_RESET_* */

 * #param flags	DEVF_RESET_*
 */
int
bus_helper_reset_prepare(device_t dev, int flags)
{
	device_t child;
	int error;

	if (dev->state != DS_ATTACHED)
		return (EBUSY);

	TAILQ_FOREACH_REVERSE(child, &dev->children, device_list, link) {
		if ((flags & DEVF_RESET_DETACH) != 0) {
			error = device_get_state(child) == DS_ATTACHED ?
			    device_detach(child) : 0;
		} else {
			error = BUS_SUSPEND_CHILD(dev, child);
		}
		if (error == 0) {
			error = BUS_RESET_PREPARE(dev, child);
			if (error != 0) {
				if ((flags & DEVF_RESET_DETACH) != 0)
					device_probe_and_attach(child);
				else
					BUS_RESUME_CHILD(dev, child);
			}
		}
		if (error != 0) {
			bus_helper_reset_prepare_rollback(dev, child, flags);
			return (error);
		}
	}
	return (0);
}

/**
 * @brief Helper function for implementing BUS_PRINT_CHILD().