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167 lines
5.4 KiB
167 lines
5.4 KiB
.. SPDX-License-Identifier: GPL-2.0 |
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=================================================================== |
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PCI Non-Transparent Bridge (NTB) Endpoint Function (EPF) User Guide |
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=================================================================== |
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:Author: Frank Li <[email protected]> |
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This document is a guide to help users use pci-epf-vntb function driver |
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and ntb_hw_epf host driver for NTB functionality. The list of steps to |
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be followed in the host side and EP side is given below. For the hardware |
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configuration and internals of NTB using configurable endpoints see |
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Documentation/PCI/endpoint/pci-vntb-function.rst |
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Endpoint Device |
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=============== |
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Endpoint Controller Devices |
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--------------------------- |
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To find the list of endpoint controller devices in the system:: |
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# ls /sys/class/pci_epc/ |
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5f010000.pcie_ep |
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If PCI_ENDPOINT_CONFIGFS is enabled:: |
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# ls /sys/kernel/config/pci_ep/controllers |
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5f010000.pcie_ep |
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Endpoint Function Drivers |
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------------------------- |
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To find the list of endpoint function drivers in the system:: |
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# ls /sys/bus/pci-epf/drivers |
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pci_epf_ntb pci_epf_test pci_epf_vntb |
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If PCI_ENDPOINT_CONFIGFS is enabled:: |
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# ls /sys/kernel/config/pci_ep/functions |
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pci_epf_ntb pci_epf_test pci_epf_vntb |
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Creating pci-epf-vntb Device |
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---------------------------- |
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PCI endpoint function device can be created using the configfs. To create |
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pci-epf-vntb device, the following commands can be used:: |
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# mount -t configfs none /sys/kernel/config |
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# cd /sys/kernel/config/pci_ep/ |
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# mkdir functions/pci_epf_vntb/func1 |
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The "mkdir func1" above creates the pci-epf-ntb function device that will |
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be probed by pci_epf_vntb driver. |
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The PCI endpoint framework populates the directory with the following |
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configurable fields:: |
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# ls functions/pci_epf_ntb/func1 |
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baseclass_code deviceid msi_interrupts pci-epf-ntb.0 |
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progif_code secondary subsys_id vendorid |
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cache_line_size interrupt_pin msix_interrupts primary |
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revid subclass_code subsys_vendor_id |
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The PCI endpoint function driver populates these entries with default values |
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when the device is bound to the driver. The pci-epf-vntb driver populates |
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vendorid with 0xffff and interrupt_pin with 0x0001:: |
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# cat functions/pci_epf_vntb/func1/vendorid |
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0xffff |
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# cat functions/pci_epf_vntb/func1/interrupt_pin |
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0x0001 |
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Configuring pci-epf-vntb Device |
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------------------------------- |
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The user can configure the pci-epf-vntb device using its configfs entry. In order |
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to change the vendorid and the deviceid, the following |
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commands can be used:: |
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# echo 0x1957 > functions/pci_epf_vntb/func1/vendorid |
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# echo 0x0809 > functions/pci_epf_vntb/func1/deviceid |
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In order to configure NTB specific attributes, a new sub-directory to func1 |
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should be created:: |
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# mkdir functions/pci_epf_vntb/func1/pci_epf_vntb.0/ |
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The NTB function driver will populate this directory with various attributes |
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that can be configured by the user:: |
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# ls functions/pci_epf_vntb/func1/pci_epf_vntb.0/ |
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db_count mw1 mw2 mw3 mw4 num_mws |
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spad_count |
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A sample configuration for NTB function is given below:: |
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# echo 4 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/db_count |
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# echo 128 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/spad_count |
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# echo 1 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/num_mws |
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# echo 0x100000 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/mw1 |
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A sample configuration for virtual NTB driver for virutal PCI bus:: |
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# echo 0x1957 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vntb_vid |
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# echo 0x080A > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vntb_pid |
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# echo 0x10 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/vbus_number |
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Binding pci-epf-ntb Device to EP Controller |
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-------------------------------------------- |
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NTB function device should be attached to PCI endpoint controllers |
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connected to the host. |
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# ln -s controllers/5f010000.pcie_ep functions/pci-epf-ntb/func1/primary |
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Once the above step is completed, the PCI endpoint controllers are ready to |
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establish a link with the host. |
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Start the Link |
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-------------- |
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In order for the endpoint device to establish a link with the host, the _start_ |
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field should be populated with '1'. For NTB, both the PCI endpoint controllers |
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should establish link with the host (imx8 don't need this steps):: |
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# echo 1 > controllers/5f010000.pcie_ep/start |
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RootComplex Device |
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================== |
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lspci Output at Host side |
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------------------------- |
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Note that the devices listed here correspond to the values populated in |
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"Creating pci-epf-ntb Device" section above:: |
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# lspci |
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00:00.0 PCI bridge: Freescale Semiconductor Inc Device 0000 (rev 01) |
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01:00.0 RAM memory: Freescale Semiconductor Inc Device 0809 |
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Endpoint Device / Virtual PCI bus |
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================================= |
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lspci Output at EP Side / Virtual PCI bus |
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----------------------------------------- |
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Note that the devices listed here correspond to the values populated in |
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"Creating pci-epf-ntb Device" section above:: |
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# lspci |
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10:00.0 Unassigned class [ffff]: Dawicontrol Computersysteme GmbH Device 1234 (rev ff) |
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Using ntb_hw_epf Device |
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----------------------- |
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The host side software follows the standard NTB software architecture in Linux. |
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All the existing client side NTB utilities like NTB Transport Client and NTB |
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Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB |
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function device. |
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For more information on NTB see |
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:doc:`Non-Transparent Bridge <../../driver-api/ntb>`
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