1 .. SPDX-License-Identifier: GPL-2.0 2 3 =================================================================== 4 PCI Non-Transparent Bridge (NTB) Endpoint Function (EPF) User Guide 5 =================================================================== 6 7 :Author: Kishon Vijay Abraham I <kishon@ti.com> 8 9 This document is a guide to help users use pci-epf-ntb function driver 10 and ntb_hw_epf host driver for NTB functionality. The list of steps to 11 be followed in the host side and EP side is given below. For the hardware 12 configuration and internals of NTB using configurable endpoints see 13 Documentation/PCI/endpoint/pci-ntb-function.rst 14 15 Endpoint Device 16 =============== 17 18 Endpoint Controller Devices 19 --------------------------- 20 21 For implementing NTB functionality at least two endpoint controller devices 22 are required. 23 24 To find the list of endpoint controller devices in the system:: 25 26 # ls /sys/class/pci_epc/ 27 2900000.pcie-ep 2910000.pcie-ep 28 29 If PCI_ENDPOINT_CONFIGFS is enabled:: 30 31 # ls /sys/kernel/config/pci_ep/controllers 32 2900000.pcie-ep 2910000.pcie-ep 33 34 35 Endpoint Function Drivers 36 ------------------------- 37 38 To find the list of endpoint function drivers in the system:: 39 40 # ls /sys/bus/pci-epf/drivers 41 pci_epf_ntb pci_epf_ntb 42 43 If PCI_ENDPOINT_CONFIGFS is enabled:: 44 45 # ls /sys/kernel/config/pci_ep/functions 46 pci_epf_ntb pci_epf_ntb 47 48 49 Creating pci-epf-ntb Device 50 ---------------------------- 51 52 PCI endpoint function device can be created using the configfs. To create 53 pci-epf-ntb device, the following commands can be used:: 54 55 # mount -t configfs none /sys/kernel/config 56 # cd /sys/kernel/config/pci_ep/ 57 # mkdir functions/pci_epf_ntb/func1 58 59 The "mkdir func1" above creates the pci-epf-ntb function device that will 60 be probed by pci_epf_ntb driver. 61 62 The PCI endpoint framework populates the directory with the following 63 configurable fields:: 64 65 # ls functions/pci_epf_ntb/func1 66 baseclass_code deviceid msi_interrupts pci-epf-ntb.0 67 progif_code secondary subsys_id vendorid 68 cache_line_size interrupt_pin msix_interrupts primary 69 revid subclass_code subsys_vendor_id 70 71 The PCI endpoint function driver populates these entries with default values 72 when the device is bound to the driver. The pci-epf-ntb driver populates 73 vendorid with 0xffff and interrupt_pin with 0x0001:: 74 75 # cat functions/pci_epf_ntb/func1/vendorid 76 0xffff 77 # cat functions/pci_epf_ntb/func1/interrupt_pin 78 0x0001 79 80 81 Configuring pci-epf-ntb Device 82 ------------------------------- 83 84 The user can configure the pci-epf-ntb device using its configfs entry. In order 85 to change the vendorid and the deviceid, the following 86 commands can be used:: 87 88 # echo 0x104c > functions/pci_epf_ntb/func1/vendorid 89 # echo 0xb00d > functions/pci_epf_ntb/func1/deviceid 90 91 The PCI endpoint framework also automatically creates a sub-directory in the 92 function attribute directory. This sub-directory has the same name as the name 93 of the function device and is populated with the following NTB specific 94 attributes that can be configured by the user:: 95 96 # ls functions/pci_epf_ntb/func1/pci_epf_ntb.0/ 97 db_count mw1 mw2 mw3 mw4 num_mws 98 spad_count 99 100 A sample configuration for NTB function is given below:: 101 102 # echo 4 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/db_count 103 # echo 128 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/spad_count 104 # echo 2 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/num_mws 105 # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw1 106 # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw2 107 108 Binding pci-epf-ntb Device to EP Controller 109 -------------------------------------------- 110 111 NTB function device should be attached to two PCI endpoint controllers 112 connected to the two hosts. Use the 'primary' and 'secondary' entries 113 inside NTB function device to attach one PCI endpoint controller to 114 primary interface and the other PCI endpoint controller to the secondary 115 interface:: 116 117 # ln -s controllers/2900000.pcie-ep/ functions/pci-epf-ntb/func1/primary 118 # ln -s controllers/2910000.pcie-ep/ functions/pci-epf-ntb/func1/secondary 119 120 Once the above step is completed, both the PCI endpoint controllers are ready to 121 establish a link with the host. 122 123 124 Start the Link 125 -------------- 126 127 In order for the endpoint device to establish a link with the host, the _start_ 128 field should be populated with '1'. For NTB, both the PCI endpoint controllers 129 should establish link with the host:: 130 131 # echo 1 > controllers/2900000.pcie-ep/start 132 # echo 1 > controllers/2910000.pcie-ep/start 133 134 135 RootComplex Device 136 ================== 137 138 lspci Output 139 ------------ 140 141 Note that the devices listed here correspond to the values populated in 142 "Creating pci-epf-ntb Device" section above:: 143 144 # lspci 145 0000:00:00.0 PCI bridge: Texas Instruments Device b00d 146 0000:01:00.0 RAM memory: Texas Instruments Device b00d 147 148 149 Using ntb_hw_epf Device 150 ----------------------- 151 152 The host side software follows the standard NTB software architecture in Linux. 153 All the existing client side NTB utilities like NTB Transport Client and NTB 154 Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB 155 function device. 156 157 For more information on NTB see 158 :doc:`Non-Transparent Bridge <../../driver-api/ntb>`
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