# SPDX-License-Identifier: GPL-2.0-only
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config NTB_IDT
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tristate "IDT PCIe-switch Non-Transparent Bridge support"
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depends on PCI
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select HWMON
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help
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This driver supports NTB of capable IDT PCIe-switches.
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Some of the pre-initializations must be made before IDT PCIe-switch
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exposes its NT-functions correctly. It should be done by either proper
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initialization of EEPROM connected to master SMbus of the switch or
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by BIOS using slave-SMBus interface changing corresponding registers
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value. Evidently it must be done before PCI bus enumeration is
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finished in Linux kernel.
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First of all partitions must be activated and properly assigned to all
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the ports with NT-functions intended to be activated (see SWPARTxCTL
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and SWPORTxCTL registers). Then all NT-function BARs must be enabled
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with chosen valid aperture. For memory windows related BARs the
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aperture settings shall determine the maximum size of memory windows
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accepted by a BAR. Note that BAR0 must map PCI configuration space
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registers.
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It's worth to note, that since a part of this driver relies on the
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BAR settings of peer NT-functions, the BAR setups can't be done over
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kernel PCI fixups. That's why the alternative pre-initialization
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techniques like BIOS using SMBus interface or EEPROM should be
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utilized.
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If unsure, say N.
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