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