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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: Frank Li <Frank.Li@nxp.com>8 9This document is a guide to help users use pci-epf-vntb 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-vntb-function.rst14 15Endpoint Device16===============17 18Endpoint Controller Devices19---------------------------20 21To find the list of endpoint controller devices in the system::22 23 # ls /sys/class/pci_epc/24 5f010000.pcie_ep25 26If PCI_ENDPOINT_CONFIGFS is enabled::27 28 # ls /sys/kernel/config/pci_ep/controllers29 5f010000.pcie_ep30 31Endpoint Function Drivers32-------------------------33 34To find the list of endpoint function drivers in the system::35 36 # ls /sys/bus/pci-epf/drivers37 pci_epf_ntb pci_epf_test pci_epf_vntb38 39If PCI_ENDPOINT_CONFIGFS is enabled::40 41 # ls /sys/kernel/config/pci_ep/functions42 pci_epf_ntb pci_epf_test pci_epf_vntb43 44 45Creating pci-epf-vntb Device46----------------------------47 48PCI endpoint function device can be created using the configfs. To create49pci-epf-vntb device, the following commands can be used::50 51 # mount -t configfs none /sys/kernel/config52 # cd /sys/kernel/config/pci_ep/53 # mkdir functions/pci_epf_vntb/func154 55The "mkdir func1" above creates the pci-epf-ntb function device that will56be probed by pci_epf_vntb driver.57 58The PCI endpoint framework populates the directory with the following59configurable fields::60 61 # ls functions/pci_epf_ntb/func162 baseclass_code deviceid msi_interrupts pci-epf-ntb.063 progif_code secondary subsys_id vendorid64 cache_line_size interrupt_pin msix_interrupts primary65 revid subclass_code subsys_vendor_id66 67The PCI endpoint function driver populates these entries with default values68when the device is bound to the driver. The pci-epf-vntb driver populates69vendorid with 0xffff and interrupt_pin with 0x0001::70 71 # cat functions/pci_epf_vntb/func1/vendorid72 0xffff73 # cat functions/pci_epf_vntb/func1/interrupt_pin74 0x000175 76 77Configuring pci-epf-vntb Device78-------------------------------79 80The user can configure the pci-epf-vntb device using its configfs entry. In order81to change the vendorid and the deviceid, the following82commands can be used::83 84 # echo 0x1957 > functions/pci_epf_vntb/func1/vendorid85 # echo 0x0809 > functions/pci_epf_vntb/func1/deviceid86 87The PCI endpoint framework also automatically creates a sub-directory in the88function attribute directory. This sub-directory has the same name as the name89of the function device and is populated with the following NTB specific90attributes 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_mws94 spad_count95 96A sample configuration for NTB function is given below::97 98 # echo 4 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/db_count99 # echo 128 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/spad_count100 # echo 1 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/num_mws101 # echo 0x100000 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/mw1102 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_vid106 # echo 0x080A > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vntb_pid107 # echo 0x10 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vbus_number108 109Binding pci-epf-ntb Device to EP Controller110--------------------------------------------111 112NTB function device should be attached to PCI endpoint controllers113connected to the host.114 115 # ln -s controllers/5f010000.pcie_ep functions/pci-epf-ntb/func1/primary116 117Once the above step is completed, the PCI endpoint controllers are ready to118establish a link with the host.119 120 121Start the Link122--------------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 controllers126should establish link with the host (imx8 don't need this steps)::127 128 # echo 1 > controllers/5f010000.pcie_ep/start129 130RootComplex Device131==================132 133lspci Output at Host side134-------------------------135 136Note that the devices listed here correspond to the values populated in137"Creating pci-epf-ntb Device" section above::138 139 # lspci140 00:00.0 PCI bridge: Freescale Semiconductor Inc Device 0000 (rev 01)141 01:00.0 RAM memory: Freescale Semiconductor Inc Device 0809142 143Endpoint Device / Virtual PCI bus144=================================145 146lspci Output at EP Side / Virtual PCI bus147-----------------------------------------148 149Note that the devices listed here correspond to the values populated in150"Creating pci-epf-ntb Device" section above::151 152 # lspci153 10:00.0 Unassigned class [ffff]: Dawicontrol Computersysteme GmbH Device 1234 (rev ff)154 155Using ntb_hw_epf Device156-----------------------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 NTB160Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB161function device.162 163For more information on NTB see164:doc:`Non-Transparent Bridge <../../driver-api/ntb>`165