CONFIG_SWIOTLB (not configurable)

modulename: dma.ko

and/or

swiotlb.ko

and/or

pci-swiotlb.ko

and/or

dma-swiotlb.ko

configname: CONFIG_SWIOTLB

Linux Kernel Configuration
└─>Library routines
└─>SWIOTLB
In linux kernel since version 2.6.12  
source code:
arch/mips/sibyte/common/dma.c