The P410 does not support JBOD. That means you’d be forced to create the RAID array on the controller, negating all of the RAID management features of BTRFS, or you’ll have to set up multiple RAID 0 arrays to put into a software RAID5 array with BTRFS. Neither situation is ideal.
I have a similar SmartArray model in my server and it’s very frustrating. You do not want to use this controller for Rockstor.
A better solution would be to get a cheap fake RAID controller that will present the unmolested block devices to the OS. Otherwise you’re missing out on the entire point of running BTRFS RAID.