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1.. SPDX-License-Identifier: GPL-2.02 3===================================================================4PCI Non-Transparent Bridge (NTB) Endpoint Function (EPF) User Guide5===================================================================6 7:Author: Kishon Vijay Abraham I <kishon@ti.com>8 9This document is a guide to help users use pci-epf-ntb function driver10and ntb_hw_epf host driver for NTB functionality. The list of steps to11be followed in the host side and EP side is given below. For the hardware12configuration and internals of NTB using configurable endpoints see13Documentation/PCI/endpoint/pci-ntb-function.rst14 15Endpoint Device16===============17 18Endpoint Controller Devices19---------------------------20 21For implementing NTB functionality at least two endpoint controller devices22are required.23 24To find the list of endpoint controller devices in the system::25 26 # ls /sys/class/pci_epc/27 2900000.pcie-ep 2910000.pcie-ep28 29If PCI_ENDPOINT_CONFIGFS is enabled::30 31 # ls /sys/kernel/config/pci_ep/controllers32 2900000.pcie-ep 2910000.pcie-ep33 34 35Endpoint Function Drivers36-------------------------37 38To find the list of endpoint function drivers in the system::39 40 # ls /sys/bus/pci-epf/drivers41 pci_epf_ntb pci_epf_ntb42 43If PCI_ENDPOINT_CONFIGFS is enabled::44 45 # ls /sys/kernel/config/pci_ep/functions46 pci_epf_ntb pci_epf_ntb47 48 49Creating pci-epf-ntb Device50----------------------------51 52PCI endpoint function device can be created using the configfs. To create53pci-epf-ntb device, the following commands can be used::54 55 # mount -t configfs none /sys/kernel/config56 # cd /sys/kernel/config/pci_ep/57 # mkdir functions/pci_epf_ntb/func158 59The "mkdir func1" above creates the pci-epf-ntb function device that will60be probed by pci_epf_ntb driver.61 62The PCI endpoint framework populates the directory with the following63configurable fields::64 65 # ls functions/pci_epf_ntb/func166 baseclass_code deviceid msi_interrupts pci-epf-ntb.067 progif_code secondary subsys_id vendorid68 cache_line_size interrupt_pin msix_interrupts primary69 revid subclass_code subsys_vendor_id70 71The PCI endpoint function driver populates these entries with default values72when the device is bound to the driver. The pci-epf-ntb driver populates73vendorid with 0xffff and interrupt_pin with 0x0001::74 75 # cat functions/pci_epf_ntb/func1/vendorid76 0xffff77 # cat functions/pci_epf_ntb/func1/interrupt_pin78 0x000179 80 81Configuring pci-epf-ntb Device82-------------------------------83 84The user can configure the pci-epf-ntb device using its configfs entry. In order85to change the vendorid and the deviceid, the following86commands can be used::87 88 # echo 0x104c > functions/pci_epf_ntb/func1/vendorid89 # echo 0xb00d > functions/pci_epf_ntb/func1/deviceid90 91The PCI endpoint framework also automatically creates a sub-directory in the92function attribute directory. This sub-directory has the same name as the name93of the function device and is populated with the following NTB specific94attributes that can be configured by the user::95 96 # ls functions/pci_epf_ntb/func1/pci_epf_ntb.0/97 db_count mw1 mw2 mw3 mw4 num_mws98 spad_count99 100A sample configuration for NTB function is given below::101 102 # echo 4 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/db_count103 # echo 128 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/spad_count104 # echo 2 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/num_mws105 # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw1106 # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw2107 108Binding pci-epf-ntb Device to EP Controller109--------------------------------------------110 111NTB function device should be attached to two PCI endpoint controllers112connected to the two hosts. Use the 'primary' and 'secondary' entries113inside NTB function device to attach one PCI endpoint controller to114primary interface and the other PCI endpoint controller to the secondary115interface::116 117 # ln -s controllers/2900000.pcie-ep/ functions/pci-epf-ntb/func1/primary118 # ln -s controllers/2910000.pcie-ep/ functions/pci-epf-ntb/func1/secondary119 120Once the above step is completed, both the PCI endpoint controllers are ready to121establish a link with the host.122 123 124Start the Link125--------------126 127In order for the endpoint device to establish a link with the host, the _start_128field should be populated with '1'. For NTB, both the PCI endpoint controllers129should establish link with the host::130 131 # echo 1 > controllers/2900000.pcie-ep/start132 # echo 1 > controllers/2910000.pcie-ep/start133 134 135RootComplex Device136==================137 138lspci Output139------------140 141Note that the devices listed here correspond to the values populated in142"Creating pci-epf-ntb Device" section above::143 144 # lspci145 0000:00:00.0 PCI bridge: Texas Instruments Device b00d146 0000:01:00.0 RAM memory: Texas Instruments Device b00d147 148 149Using ntb_hw_epf Device150-----------------------151 152The host side software follows the standard NTB software architecture in Linux.153All the existing client side NTB utilities like NTB Transport Client and NTB154Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB155function device.156 157For more information on NTB see158:doc:`Non-Transparent Bridge <../../driver-api/ntb>`159