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 87In order to configure NTB specific attributes, a new sub-directory to func1 88should be created:: 89 90 # mkdir functions/pci_epf_vntb/func1/pci_epf_vntb.0/ 91 92The NTB function driver will populate this directory with various attributes 93that can be configured by the user:: 94 95 # ls functions/pci_epf_vntb/func1/pci_epf_vntb.0/ 96 db_count mw1 mw2 mw3 mw4 num_mws 97 spad_count 98 99A sample configuration for NTB function is given below:: 100 101 # echo 4 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/db_count 102 # echo 128 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/spad_count 103 # echo 1 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/num_mws 104 # echo 0x100000 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/mw1 105 106A sample configuration for virtual NTB driver for virutal PCI bus:: 107 108 # echo 0x1957 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vntb_vid 109 # echo 0x080A > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vntb_pid 110 # echo 0x10 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vbus_number 111 112Binding pci-epf-ntb Device to EP Controller 113-------------------------------------------- 114 115NTB function device should be attached to PCI endpoint controllers 116connected to the host. 117 118 # ln -s controllers/5f010000.pcie_ep functions/pci-epf-ntb/func1/primary 119 120Once the above step is completed, 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 (imx8 don't need this steps):: 130 131 # echo 1 > controllers/5f010000.pcie_ep/start 132 133RootComplex Device 134================== 135 136lspci Output at Host side 137------------------------- 138 139Note that the devices listed here correspond to the values populated in 140"Creating pci-epf-ntb Device" section above:: 141 142 # lspci 143 00:00.0 PCI bridge: Freescale Semiconductor Inc Device 0000 (rev 01) 144 01:00.0 RAM memory: Freescale Semiconductor Inc Device 0809 145 146Endpoint Device / Virtual PCI bus 147================================= 148 149lspci Output at EP Side / Virtual PCI bus 150----------------------------------------- 151 152Note that the devices listed here correspond to the values populated in 153"Creating pci-epf-ntb Device" section above:: 154 155 # lspci 156 10:00.0 Unassigned class [ffff]: Dawicontrol Computersysteme GmbH Device 1234 (rev ff) 157 158Using ntb_hw_epf Device 159----------------------- 160 161The host side software follows the standard NTB software architecture in Linux. 162All the existing client side NTB utilities like NTB Transport Client and NTB 163Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB 164function device. 165 166For more information on NTB see 167:doc:`Non-Transparent Bridge <../../driver-api/ntb>` 168