1.. SPDX-License-Identifier: GPL-2.0 2 3=================================================================== 4PCI Non-Transparent Bridge (NTB) Endpoint Function (EPF) User Guide 5=================================================================== 6 7:Author: Frank Li <Frank.Li@nxp.com> 8 9This document is a guide to help users use pci-epf-vntb 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-vntb-function.rst 14 15Endpoint Device 16=============== 17 18Endpoint Controller Devices 19--------------------------- 20 21To find the list of endpoint controller devices in the system:: 22 23 # ls /sys/class/pci_epc/ 24 5f010000.pcie_ep 25 26If PCI_ENDPOINT_CONFIGFS is enabled:: 27 28 # ls /sys/kernel/config/pci_ep/controllers 29 5f010000.pcie_ep 30 31Endpoint Function Drivers 32------------------------- 33 34To find the list of endpoint function drivers in the system:: 35 36 # ls /sys/bus/pci-epf/drivers 37 pci_epf_ntb pci_epf_test pci_epf_vntb 38 39If PCI_ENDPOINT_CONFIGFS is enabled:: 40 41 # ls /sys/kernel/config/pci_ep/functions 42 pci_epf_ntb pci_epf_test pci_epf_vntb 43 44 45Creating pci-epf-vntb Device 46---------------------------- 47 48PCI endpoint function device can be created using the configfs. To create 49pci-epf-vntb device, the following commands can be used:: 50 51 # mount -t configfs none /sys/kernel/config 52 # cd /sys/kernel/config/pci_ep/ 53 # mkdir functions/pci_epf_vntb/func1 54 55The "mkdir func1" above creates the pci-epf-ntb function device that will 56be probed by pci_epf_vntb driver. 57 58The PCI endpoint framework populates the directory with the following 59configurable fields:: 60 61 # ls functions/pci_epf_ntb/func1 62 baseclass_code deviceid msi_interrupts pci-epf-ntb.0 63 progif_code secondary subsys_id vendorid 64 cache_line_size interrupt_pin msix_interrupts primary 65 revid subclass_code subsys_vendor_id 66 67The PCI endpoint function driver populates these entries with default values 68when the device is bound to the driver. The pci-epf-vntb driver populates 69vendorid with 0xffff and interrupt_pin with 0x0001:: 70 71 # cat functions/pci_epf_vntb/func1/vendorid 72 0xffff 73 # cat functions/pci_epf_vntb/func1/interrupt_pin 74 0x0001 75 76 77Configuring pci-epf-vntb Device 78------------------------------- 79 80The user can configure the pci-epf-vntb device using its configfs entry. In order 81to change the vendorid and the deviceid, the following 82commands can be used:: 83 84 # echo 0x1957 > functions/pci_epf_vntb/func1/vendorid 85 # echo 0x0809 > functions/pci_epf_vntb/func1/deviceid 86 87The PCI endpoint framework also automatically creates a sub-directory in the 88function attribute directory. This sub-directory has the same name as the name 89of the function device and is populated with the following NTB specific 90attributes that can be configured by the user:: 91 92 # ls functions/pci_epf_vntb/func1/pci_epf_vntb.0/ 93 db_count mw1 mw2 mw3 mw4 num_mws 94 spad_count 95 96A sample configuration for NTB function is given below:: 97 98 # echo 4 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/db_count 99 # echo 128 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/spad_count 100 # echo 1 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/num_mws 101 # echo 0x100000 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/mw1 102 103A sample configuration for virtual NTB driver for virtual PCI bus:: 104 105 # echo 0x1957 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vntb_vid 106 # echo 0x080A > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vntb_pid 107 # echo 0x10 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vbus_number 108 109Binding pci-epf-ntb Device to EP Controller 110-------------------------------------------- 111 112NTB function device should be attached to PCI endpoint controllers 113connected to the host. 114 115 # ln -s controllers/5f010000.pcie_ep functions/pci-epf-ntb/func1/primary 116 117Once the above step is completed, the PCI endpoint controllers are ready to 118establish a link with the host. 119 120 121Start the Link 122-------------- 123 124In order for the endpoint device to establish a link with the host, the _start_ 125field should be populated with '1'. For NTB, both the PCI endpoint controllers 126should establish link with the host (imx8 don't need this steps):: 127 128 # echo 1 > controllers/5f010000.pcie_ep/start 129 130RootComplex Device 131================== 132 133lspci Output at Host side 134------------------------- 135 136Note that the devices listed here correspond to the values populated in 137"Creating pci-epf-ntb Device" section above:: 138 139 # lspci 140 00:00.0 PCI bridge: Freescale Semiconductor Inc Device 0000 (rev 01) 141 01:00.0 RAM memory: Freescale Semiconductor Inc Device 0809 142 143Endpoint Device / Virtual PCI bus 144================================= 145 146lspci Output at EP Side / Virtual PCI bus 147----------------------------------------- 148 149Note that the devices listed here correspond to the values populated in 150"Creating pci-epf-ntb Device" section above:: 151 152 # lspci 153 10:00.0 Unassigned class [ffff]: Dawicontrol Computersysteme GmbH Device 1234 (rev ff) 154 155Using ntb_hw_epf Device 156----------------------- 157 158The host side software follows the standard NTB software architecture in Linux. 159All the existing client side NTB utilities like NTB Transport Client and NTB 160Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB 161function device. 162 163For more information on NTB see 164:doc:`Non-Transparent Bridge <../../driver-api/ntb>` 165