xref: /openbmc/linux/drivers/ntb/hw/idt/Kconfig (revision a662315d)
1bf2a952dSSerge Seminconfig NTB_IDT
2bf2a952dSSerge Semin	tristate "IDT PCIe-switch Non-Transparent Bridge support"
3bf2a952dSSerge Semin	depends on PCI
4aed1b7b3SSerge Semin	select HWMON
5bf2a952dSSerge Semin	help
6bf2a952dSSerge Semin	 This driver supports NTB of cappable IDT PCIe-switches.
7bf2a952dSSerge Semin
8bf2a952dSSerge Semin	 Some of the pre-initializations must be made before IDT PCIe-switch
9bf2a952dSSerge Semin	 exposes it NT-functions correctly. It should be done by either proper
10bf2a952dSSerge Semin	 initialisation of EEPROM connected to master smbus of the switch or
11bf2a952dSSerge Semin	 by BIOS using slave-SMBus interface changing corresponding registers
12bf2a952dSSerge Semin	 value. Evidently it must be done before PCI bus enumeration is
13bf2a952dSSerge Semin	 finished in Linux kernel.
14bf2a952dSSerge Semin
15bf2a952dSSerge Semin	 First of all partitions must be activated and properly assigned to all
16bf2a952dSSerge Semin	 the ports with NT-functions intended to be activated (see SWPARTxCTL
17bf2a952dSSerge Semin	 and SWPORTxCTL registers). Then all NT-function BARs must be enabled
18bf2a952dSSerge Semin	 with chosen valid aperture. For memory windows related BARs the
19bf2a952dSSerge Semin	 aperture settings shall determine the maximum size of memory windows
20bf2a952dSSerge Semin	 accepted by a BAR. Note that BAR0 must map PCI configuration space
21bf2a952dSSerge Semin	 registers.
22bf2a952dSSerge Semin
23bf2a952dSSerge Semin	 It's worth to note, that since a part of this driver relies on the
24bf2a952dSSerge Semin	 BAR settings of peer NT-functions, the BAR setups can't be done over
25bf2a952dSSerge Semin	 kernel PCI fixups. That's why the alternative pre-initialization
26bf2a952dSSerge Semin	 techniques like BIOS using SMBus interface or EEPROM should be
27a662315dSSerge Semin	 utilized.
28bf2a952dSSerge Semin
29bf2a952dSSerge Semin	 If unsure, say N.
30bf2a952dSSerge Semin
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