165 lines
5.4 KiB
ReStructuredText
165 lines
5.4 KiB
ReStructuredText
.. 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 <Frank.Li@nxp.com>
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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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The PCI endpoint framework also automatically creates a sub-directory in the
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function attribute directory. This sub-directory has the same name as the name
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of the function device and is populated with the following NTB specific
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attributes 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 virtual 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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