1.. SPDX-License-Identifier: GPL-2.0 2 3=================================================================== 4PCI Non-Transparent Bridge (NTB) Endpoint Function (EPF) User Guide 5=================================================================== 6 7:Author: Kishon Vijay Abraham I <kishon@ti.com> 8 9This document is a guide to help users use pci-epf-ntb function driver 10and ntb_hw_epf host driver for NTB functionality. The list of steps to 11be followed in the host side and EP side is given below. For the hardware 12configuration and internals of NTB using configurable endpoints see 13Documentation/PCI/endpoint/pci-ntb-function.rst 14 15Endpoint Device 16=============== 17 18Endpoint Controller Devices 19--------------------------- 20 21For implementing NTB functionality at least two endpoint controller devices 22are 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-ep 28 29If PCI_ENDPOINT_CONFIGFS is enabled:: 30 31 # ls /sys/kernel/config/pci_ep/controllers 32 2900000.pcie-ep 2910000.pcie-ep 33 34 35Endpoint Function Drivers 36------------------------- 37 38To find the list of endpoint function drivers in the system:: 39 40 # ls /sys/bus/pci-epf/drivers 41 pci_epf_ntb pci_epf_ntb 42 43If PCI_ENDPOINT_CONFIGFS is enabled:: 44 45 # ls /sys/kernel/config/pci_ep/functions 46 pci_epf_ntb pci_epf_ntb 47 48 49Creating pci-epf-ntb Device 50---------------------------- 51 52PCI endpoint function device can be created using the configfs. To create 53pci-epf-ntb device, the following commands can be used:: 54 55 # mount -t configfs none /sys/kernel/config 56 # cd /sys/kernel/config/pci_ep/ 57 # mkdir functions/pci_epf_ntb/func1 58 59The "mkdir func1" above creates the pci-epf-ntb function device that will 60be probed by pci_epf_ntb driver. 61 62The PCI endpoint framework populates the directory with the following 63configurable fields:: 64 65 # ls functions/pci_epf_ntb/func1 66 baseclass_code deviceid msi_interrupts pci-epf-ntb.0 67 progif_code secondary subsys_id vendorid 68 cache_line_size interrupt_pin msix_interrupts primary 69 revid subclass_code subsys_vendor_id 70 71The PCI endpoint function driver populates these entries with default values 72when the device is bound to the driver. The pci-epf-ntb driver populates 73vendorid with 0xffff and interrupt_pin with 0x0001:: 74 75 # cat functions/pci_epf_ntb/func1/vendorid 76 0xffff 77 # cat functions/pci_epf_ntb/func1/interrupt_pin 78 0x0001 79 80 81Configuring pci-epf-ntb Device 82------------------------------- 83 84The user can configure the pci-epf-ntb device using its configfs entry. In order 85to change the vendorid and the deviceid, the following 86commands can be used:: 87 88 # echo 0x104c > functions/pci_epf_ntb/func1/vendorid 89 # echo 0xb00d > functions/pci_epf_ntb/func1/deviceid 90 91The PCI endpoint framework also automatically creates a sub-directory in the 92function attribute directory. This sub-directory has the same name as the name 93of the function device and is populated with the following NTB specific 94attributes 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_mws 98 spad_count 99 100A sample configuration for NTB function is given below:: 101 102 # echo 4 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/db_count 103 # echo 128 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/spad_count 104 # echo 2 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/num_mws 105 # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw1 106 # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw2 107 108Binding pci-epf-ntb Device to EP Controller 109-------------------------------------------- 110 111NTB function device should be attached to two PCI endpoint controllers 112connected to the two hosts. Use the 'primary' and 'secondary' entries 113inside NTB function device to attach one PCI endpoint controller to 114primary interface and the other PCI endpoint controller to the secondary 115interface:: 116 117 # ln -s controllers/2900000.pcie-ep/ functions/pci-epf-ntb/func1/primary 118 # ln -s controllers/2910000.pcie-ep/ functions/pci-epf-ntb/func1/secondary 119 120Once the above step is completed, both the PCI endpoint controllers are ready to 121establish a link with the host. 122 123 124Start the Link 125-------------- 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 controllers 129should establish link with the host:: 130 131 # echo 1 > controllers/2900000.pcie-ep/start 132 # echo 1 > controllers/2910000.pcie-ep/start 133 134 135RootComplex Device 136================== 137 138lspci Output 139------------ 140 141Note that the devices listed here correspond to the values populated in 142"Creating pci-epf-ntb Device" section above:: 143 144 # lspci 145 0000:00:00.0 PCI bridge: Texas Instruments Device b00d 146 0000:01:00.0 RAM memory: Texas Instruments Device b00d 147 148 149Using ntb_hw_epf Device 150----------------------- 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 NTB 154Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB 155function device. 156 157For more information on NTB see 158:doc:`Non-Transparent Bridge <../../driver-api/ntb>` 159