linux-arkmicro/linux/drivers/ntb/hw/idt/Kconfig

config NTB_IDT
	tristate "IDT PCIe-switch Non-Transparent Bridge support"
	depends on PCI
	help
	 This driver supports NTB of cappable IDT PCIe-switches.

	 Some of the pre-initializations must be made before IDT PCIe-switch
	 exposes it NT-functions correctly. It should be done by either proper
	 initialisation of EEPROM connected to master smbus of the switch or
	 by BIOS using slave-SMBus interface changing corresponding registers
	 value. Evidently it must be done before PCI bus enumeration is
	 finished in Linux kernel.

	 First of all partitions must be activated and properly assigned to all
	 the ports with NT-functions intended to be activated (see SWPARTxCTL
	 and SWPORTxCTL registers). Then all NT-function BARs must be enabled
	 with chosen valid aperture. For memory windows related BARs the
	 aperture settings shall determine the maximum size of memory windows
	 accepted by a BAR. Note that BAR0 must map PCI configuration space
	 registers.

	 It's worth to note, that since a part of this driver relies on the
	 BAR settings of peer NT-functions, the BAR setups can't be done over
	 kernel PCI fixups. That's why the alternative pre-initialization
	 techniques like BIOS using SMBus interface or EEPROM should be
	 utilized. Additionally if one needs to have temperature sensor
	 information printed to system log, the corresponding registers must
	 be initialized within BIOS/EEPROM as well.

	 If unsure, say N.