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