9.5. PCI Test User Guide — The Linux Kernel 6.14.0-gnu-rt3-parabola1-1-rt documentation

# 9.5. PCI Test User Guide

Author:

  Kishon Vijay Abraham I <kishon@ti.com>

This document is a guide to help users use pci-epf-test function driver and pci_endpoint_test host driver for testing PCI. The list of steps to be followed in the host side and EP side is given below.

## 9.5.1. Endpoint Device

### 9.5.1.1. Endpoint Controller Devices

To find the list of endpoint controller devices in the system:

    # ls /sys/class/pci_epc/
      51000000.pcie_ep

If PCI_ENDPOINT_CONFIGFS is enabled:

    # ls /sys/kernel/config/pci_ep/controllers
      51000000.pcie_ep

### 9.5.1.2. Endpoint Function Drivers

To find the list of endpoint function drivers in the system:

    # ls /sys/bus/pci-epf/drivers
      pci_epf_test

If PCI_ENDPOINT_CONFIGFS is enabled:

    # ls /sys/kernel/config/pci_ep/functions
      pci_epf_test

### 9.5.1.3. Creating pci-epf-test Device

PCI endpoint function device can be created using the configfs. To create pci-epf-test device, the following commands can be used:

    # mount -t configfs none /sys/kernel/config
    # cd /sys/kernel/config/pci_ep/
    # mkdir functions/pci_epf_test/func1

The “mkdir func1” above creates the pci-epf-test function device that will be probed by pci_epf_test driver.

The PCI endpoint framework populates the directory with the following configurable fields:

    # ls functions/pci_epf_test/func1
      baseclass_code        interrupt_pin   progif_code     subsys_id
      cache_line_size       msi_interrupts  revid           subsys_vendorid
      deviceid              msix_interrupts subclass_code   vendorid

The PCI endpoint function driver populates these entries with default values when the device is bound to the driver. The pci-epf-test driver populates vendorid with 0xffff and interrupt_pin with 0x0001:

    # cat functions/pci_epf_test/func1/vendorid
      0xffff
    # cat functions/pci_epf_test/func1/interrupt_pin
      0x0001

### 9.5.1.4. Configuring pci-epf-test Device

The user can configure the pci-epf-test device using configfs entry. In order to change the vendorid and the number of MSI interrupts used by the function device, the following commands can be used:

    # echo 0x104c > functions/pci_epf_test/func1/vendorid
    # echo 0xb500 > functions/pci_epf_test/func1/deviceid
    # echo 32 > functions/pci_epf_test/func1/msi_interrupts
    # echo 2048 > functions/pci_epf_test/func1/msix_interrupts

### 9.5.1.5. Binding pci-epf-test Device to EP Controller

In order for the endpoint function device to be useful, it has to be bound to a PCI endpoint controller driver. Use the configfs to bind the function device to one of the controller driver present in the system:

    # ln -s functions/pci_epf_test/func1 controllers/51000000.pcie_ep/

Once the above step is completed, the PCI endpoint is ready to establish a link with the host.

### 9.5.1.6. Start the Link

In order for the endpoint device to establish a link with the host, the _start_ field should be populated with ‘1’:

    # echo 1 > controllers/51000000.pcie_ep/start

## 9.5.2. RootComplex Device

### 9.5.2.1. lspci Output

Note that the devices listed here correspond to the value populated in 1.4 above:

    00:00.0 PCI bridge: Texas Instruments Device 8888 (rev 01)
    01:00.0 Unassigned class [ff00]: Texas Instruments Device b500

### 9.5.2.2. Using Endpoint Test function Device

Kselftest added in tools/testing/selftests/pci_endpoint can be used to run all the default PCI endpoint tests. To build the Kselftest for PCI endpoint subsystem, the following commands should be used:

    # cd <kernel-dir>
    # make -C tools/testing/selftests/pci_endpoint

or if you desire to compile and install in your system:

    # cd <kernel-dir>
    # make -C tools/testing/selftests/pci_endpoint INSTALL_PATH=/usr/bin install

The test will be located in <rootfs>/usr/bin/

#### 9.5.2.2.1. Kselftest Output

    # pci_endpoint_test
    TAP version 13
    1..16
    # Starting 16 tests from 9 test cases.
    #  RUN           pci_ep_bar.BAR0.BAR_TEST ...
    #            OK  pci_ep_bar.BAR0.BAR_TEST
    ok 1 pci_ep_bar.BAR0.BAR_TEST
    #  RUN           pci_ep_bar.BAR1.BAR_TEST ...
    #            OK  pci_ep_bar.BAR1.BAR_TEST
    ok 2 pci_ep_bar.BAR1.BAR_TEST
    #  RUN           pci_ep_bar.BAR2.BAR_TEST ...
    #            OK  pci_ep_bar.BAR2.BAR_TEST
    ok 3 pci_ep_bar.BAR2.BAR_TEST
    #  RUN           pci_ep_bar.BAR3.BAR_TEST ...
    #            OK  pci_ep_bar.BAR3.BAR_TEST
    ok 4 pci_ep_bar.BAR3.BAR_TEST
    #  RUN           pci_ep_bar.BAR4.BAR_TEST ...
    #            OK  pci_ep_bar.BAR4.BAR_TEST
    ok 5 pci_ep_bar.BAR4.BAR_TEST
    #  RUN           pci_ep_bar.BAR5.BAR_TEST ...
    #            OK  pci_ep_bar.BAR5.BAR_TEST
    ok 6 pci_ep_bar.BAR5.BAR_TEST
    #  RUN           pci_ep_basic.CONSECUTIVE_BAR_TEST ...
    #            OK  pci_ep_basic.CONSECUTIVE_BAR_TEST
    ok 7 pci_ep_basic.CONSECUTIVE_BAR_TEST
    #  RUN           pci_ep_basic.LEGACY_IRQ_TEST ...
    #            OK  pci_ep_basic.LEGACY_IRQ_TEST
    ok 8 pci_ep_basic.LEGACY_IRQ_TEST
    #  RUN           pci_ep_basic.MSI_TEST ...
    #            OK  pci_ep_basic.MSI_TEST
    ok 9 pci_ep_basic.MSI_TEST
    #  RUN           pci_ep_basic.MSIX_TEST ...
    #            OK  pci_ep_basic.MSIX_TEST
    ok 10 pci_ep_basic.MSIX_TEST
    #  RUN           pci_ep_data_transfer.memcpy.READ_TEST ...
    #            OK  pci_ep_data_transfer.memcpy.READ_TEST
    ok 11 pci_ep_data_transfer.memcpy.READ_TEST
    #  RUN           pci_ep_data_transfer.memcpy.WRITE_TEST ...
    #            OK  pci_ep_data_transfer.memcpy.WRITE_TEST
    ok 12 pci_ep_data_transfer.memcpy.WRITE_TEST
    #  RUN           pci_ep_data_transfer.memcpy.COPY_TEST ...
    #            OK  pci_ep_data_transfer.memcpy.COPY_TEST
    ok 13 pci_ep_data_transfer.memcpy.COPY_TEST
    #  RUN           pci_ep_data_transfer.dma.READ_TEST ...
    #            OK  pci_ep_data_transfer.dma.READ_TEST
    ok 14 pci_ep_data_transfer.dma.READ_TEST
    #  RUN           pci_ep_data_transfer.dma.WRITE_TEST ...
    #            OK  pci_ep_data_transfer.dma.WRITE_TEST
    ok 15 pci_ep_data_transfer.dma.WRITE_TEST
    #  RUN           pci_ep_data_transfer.dma.COPY_TEST ...
    #            OK  pci_ep_data_transfer.dma.COPY_TEST
    ok 16 pci_ep_data_transfer.dma.COPY_TEST
    # PASSED: 16 / 16 tests passed.
    # Totals: pass:16 fail:0 xfail:0 xpass:0 skip:0 error:0

Testcase 16 (pci_ep_data_transfer.dma.COPY_TEST) will fail for most of the DMA capable endpoint controllers due to the absence of the MEMCPY over DMA. For such controllers, it is advisable to skip this testcase using this command:

    # pci_endpoint_test -f pci_ep_bar -f pci_ep_basic -v memcpy -T COPY_TEST -v dma