Hi Randy,

On 06/09/20 3:38 am, Randy Dunlap wrote:

On 9/4/20 12:50 AM, Kishon Vijay Abraham I wrote:

quoted

Add documentation to help users use pci-epf-ntb function driver and
existing host side NTB infrastructure for NTB functionality.

Signed-off-by: Kishon Vijay Abraham I <redacted>
---
 Documentation/PCI/endpoint/index.rst         |   1 +
 Documentation/PCI/endpoint/pci-ntb-howto.rst | 160 +++++++++++++++++++
 2 files changed, 161 insertions(+)
 create mode 100644 Documentation/PCI/endpoint/pci-ntb-howto.rst

Hi,
There are a few edits below:

Thanks for reviewing. I'll fix and post a new revision.

Thanks
Kishon

quoted

diff --git a/Documentation/PCI/endpoint/pci-ntb-howto.rst b/Documentation/PCI/endpoint/pci-ntb-howto.rst
new file mode 100644
index 000000000000..2fbb0a051c3b
--- /dev/null
+++ b/Documentation/PCI/endpoint/pci-ntb-howto.rst

@@ -0,0 +1,160 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================
+PCI NTB EPF User Guide
+======================
+
+:Author: Kishon Vijay Abraham I <kishon@ti.com>
+
+This document is a guide to help users use pci-epf-ntb function driver
+and ntb_hw_epf host driver for NTB functionality. The list of steps to
+be followed in the host side and EP side is given below. For the hardware
+configuration and internals of NTB using configurable endpoints see
+Documentation/PCI/endpoint/pci-ntb-function.rst
+
+Endpoint Device
+===============
+
+Endpoint Controller Devices
+---------------------------
+
+For implementing NTB functionality atleast two endpoint controller devices

                                      at least

quoted

+are required.
+To find the list of endpoint controller devices in the system::
+
+        # ls /sys/class/pci_epc/
+          2900000.pcie-ep  2910000.pcie-ep
+
+If PCI_ENDPOINT_CONFIGFS is enabled::
+
+	# ls /sys/kernel/config/pci_ep/controllers
+	  2900000.pcie-ep  2910000.pcie-ep
+
+
+Endpoint Function Drivers
+-------------------------
+
+To find the list of endpoint function drivers in the system::
+
+	# ls /sys/bus/pci-epf/drivers
+	  pci_epf_ntb   pci_epf_ntb
+
+If PCI_ENDPOINT_CONFIGFS is enabled::
+
+	# ls /sys/kernel/config/pci_ep/functions
+	  pci_epf_ntb   pci_epf_ntb
+
+
+Creating pci-epf-ntb Device
+----------------------------
+
+PCI endpoint function device can be created using the configfs. To create
+pci-epf-ntb device, the following commands can be used::
+
+	# mount -t configfs none /sys/kernel/config
+	# cd /sys/kernel/config/pci_ep/
+	# mkdir functions/pci_epf_ntb/func1
+
+The "mkdir func1" above creates the pci-epf-ntb function device that will
+be probed by pci_epf_ntb driver.
+
+The PCI endpoint framework populates the directory with the following
+configurable fields::
+
+	# ls functions/pci_epf_ntb/func1
+          baseclass_code    deviceid          msi_interrupts    pci-epf-ntb.0
+          progif_code       secondary         subsys_id         vendorid
+          cache_line_size   interrupt_pin     msix_interrupts   primary
+          revid             subclass_code     subsys_vendor_id
+
+The PCI endpoint function driver populates these entries with default values
+when the device is bound to the driver. The pci-epf-ntb driver populates
+vendorid with 0xffff and interrupt_pin with 0x0001::
+
+	# cat functions/pci_epf_ntb/func1/vendorid
+	  0xffff
+	# cat functions/pci_epf_ntb/func1/interrupt_pin
+	  0x0001
+
+
+Configuring pci-epf-ntb Device
+-------------------------------
+
+The user can configure the pci-epf-ntb device using configfs entry. In order

                                                 using its configfs entry.

quoted

+to change the vendorid and the deviceid, the following
+commands can be used::
+
+	# echo 0x104c > functions/pci_epf_ntb/func1/vendorid
+	# echo 0xb00d > functions/pci_epf_ntb/func1/deviceid
+
+In-order to configure NTB specific attributes, a new sub-directory to func1

   In order

quoted

+should be created::
+
+	# mkdir functions/pci_epf_ntb/func1/pci_epf_ntb.0/
+
+The NTB function driver will populate this directory with various attributes
+that can be configured by the user::
+
+	# ls functions/pci_epf_ntb/func1/pci_epf_ntb.0/
+          db_count    mw1         mw2         mw3         mw4         num_mws
+          spad_count
+
+A sample configuration for NTB function is given below::
+
+	# echo 4 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/db_count
+	# echo 128 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/spad_count
+	# echo 2 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/num_mws
+	# echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw1
+	# echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw2
+
+Binding pci-epf-ntb Device to EP Controller
+--------------------------------------------
+
+NTB function device should be attached to two PCIe endpoint controllers
+connected to the two hosts. Use the 'primary' and 'secondary' entries
+inside NTB function device to attach one PCIe endpoint controller to
+primary interface and the other PCIe endpoint controller to the secondary
+interface. ::
+
+        # ln -s controllers/2900000.pcie-ep/ functions/pci-epf-ntb/func1/primary
+        # ln -s controllers/2910000.pcie-ep/ functions/pci-epf-ntb/func1/secondary
+
+Once the above step is completed, both the PCI endpoint controllers is ready to

                                                                       are ready

quoted

+establish a link with the host.
+
+
+Start the Link
+--------------
+
+In order for the endpoint device to establish a link with the host, the _start_
+field should be populated with '1'. For NTB, both the PCIe endpoint controllers
+should establish link with the host::
+
+        #echo 1 > controllers/2900000.pcie-ep/start
+        #echo 1 > controllers/2910000.pcie-ep/start
+
+
+RootComplex Device
+==================
+
+lspci Output
+------------
+
+Note that the devices listed here correspond to the value populated in 1.4

Can you use a section name (or reference) here instead of "1.4"?  I can't see 1.4
when reading with an editor.

quoted

+above::
+
+        # lspci
+        0000:00:00.0 PCI bridge: Texas Instruments Device b00d
+        0000:01:00.0 RAM memory: Texas Instruments Device b00d
+
+
+Using ntb_hw_epf Device
+-----------------------
+
+The host side software follows the standard NTB software architecture in Linux.
+All the existing client side NTB utilities like NTB Transport Client and NTB
+Netdev, NTB Ping Pong Test Client and NTB Tool Test Clientcan be used with NTB

                                                       Client can be

quoted

+function device.
+
+For more information on NTB see
+Documentation/driver-api/ntb.rst

thanks.