Introduction

This page gives an overview of Root Port driver for the controller for PCI Express, which is available as part of the ZynqMP processing system.


PCI Express (abbreviated as PCIe) is the newest bus standard designed to replace the old PCI/PCI-X and AGP standards. PCIe is used in servers, consumer, and industrial applications either as a motherboard-level interconnection to link peripherals or as an expansion card interface for add on boards.

Controller for PCI Express

The Zynq® UltraScale+™ MPSoC provides a controller for the integrated block for PCI Express® v2.1 compliant, AXI-PCIe bridge, and DMA modules. The AXI-PCIe bridge provides high-performance bridging between PCIe and AXI.
The controller for PCIe supports both Endpoint and Root Port modes of operations and provides support up to x4 Gen2 links.

For more information about controller for PCI Express, please refer Zynq UltraScale+ MPSoC TRM (UG1085).

Hardware Setup

The details here are targeted to ZCU102 hardware platform.
PetaLinux ZCU102 BSP provides x2 Gen2 FSBL by default. For other link configurations, appropriate FSBL should be generated via PCW in Vivado.

zynqmp_rp.png

Tested End Point cards:
1. Broadcom PCIe NIC card
2. Realtek NIC card
3. KC705, KCU105, VCU108 with PIO designs (Xilinx PCIe Endpoint Example designs)
4. Intel NVMe SSD
5. Intel NIC card
6. PCIe-SATA
7. PCIe-USB
8. PLX Switch with Endpoint

Root Port Driver Configuration

The PCI/PCIe subsystem support and Root Port driver is enabled by default in ZynqMP kernel configuration. The related code is always built with the kernel. So, the user does not need to change anything in the configuration files to bring in PCIe support into ZynqMP kernel. The driver is built with Message Signaled Interrupts (MSI) support in default configuration.

The driver is available at:
https://github.com/Xilinx/linux-xlnx/blob/master/drivers/pci/host/pcie-xilinx-nwl.c

End Point Driver Configuration


This page demonstrates the Root Port driver using Broadcom NIC Endpoint, for which NIC driver should be enabled in kernel as shown,

pci-tg3.jpg


The following driver is needed to be enabled for using NVMe SSD as EndPoint,

nvme.jpg


For other End point cards, ensure the respective driver is loaded into kernel.

Rootfs Configuration


Enable lspci utility in rootfs under "Filesystem Packages->console/utils->pciutils->libpci3/pciutils/pciutils-ids/pciutils-lic"

Device Tree binding


The device tree node for ZynqMP PCIe core will be automatically generated, if the core is configured in the HW design, using the Device Tree BSP.

Steps to generate device-tree is documented here,
http://www.wiki.xilinx.com/Build+Device+Tree+Blob

And a sample binding is shown below and the description of DT property is documented here

nwl_pcie: pcie@fd0e0000 {
    #address-cells = <3>;
    #size-cells = <2>;
    compatible = "xlnx,nwl-pcie-2.11";
    #interrupt-cells = <1>;
    msi-controller;
    device_type = "pci";
    interrupt-parent = <&gic>;
    interrupts = <0 114 4>, <0 115 4>, <0 116 4>, <0 117 4>, <0 118 4>;
    interrupt-names = "msi0", "msi1", "intx", "dummy", "misc";
    interrupt-map-mask = <0x0 0x0 0x0 0x7>;
    interrupt-map = <0x0 0x0 0x0 0x1 &pcie_intc 0x1>,
            <0x0 0x0 0x0 0x2 &pcie_intc 0x2>,
            <0x0 0x0 0x0 0x3 &pcie_intc 0x3>,
            <0x0 0x0 0x0 0x4 &pcie_intc 0x4>;
    clocks = <&clkc 23>
 
    msi-parent = <&nwl_pcie>;
    reg = <0x0 0xfd0e0000 0x0 0x1000>,
          <0x0 0xfd480000 0x0 0x1000>,
          <0x80 0x00000000 0x0 0x1000000>;
    reg-names = "breg", "pcireg", "cfg";
    ranges = <0x02000000 0x00000000 0xe0000000 0x00000000 0xe0000000 0x00000000 0x10000000  /* non-prefetchable memory */
          0x43000000 0x00000006 0x00000000 0x00000006 0x00000000 0x00000002 0x00000000>;/* prefetchable memory */
 
    pcie_intc: legacy-interrupt-controller {
        interrupt-controller;
        #address-cells = <0>;
        #interrupt-cells = <1>;
    };
 
};

Test Procedure

  • Load the linux onto ZCU102.
  • After successful booting of the linux, will be able to see the Broadcom NIC endpoint driver is been probed. Run the command ‘lspci’ from the user prompt, which shows the the device id and manufacturer id of the Broadcom NIC card. This ensures the enumeration of the device is fine.
  • The Broadcom NIC is shown up as an eth1 interface in the linux. Run the command ‘ifconfig eth1 up’ which brings up the Ethernet interface. This step ensures all the memory transactions on the PCIe bus are working.
  • Assign a IP address either static/dhcp.
  • Ping to a device of known IP address.
  • With MSI supported linux image, it can be observed that increase in MSI interrupts count (cat /proc/interrupts).

Kernel Console Output


Driver Initialization for ZynqMP


nwl-pcie fd0e0000.pcie: Link is UP
PCI host bridge /amba/pcie@fd0e0000 ranges:
  No bus range found for /amba/pcie@fd0e0000, using [bus 00-ff]
  MEM 0xe1000000..0xefffffff -> 0xe1000000
nwl-pcie fd0e0000.pcie: PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [bus 00-ff]
pci_bus 0000:00: root bus resource [mem 0xe1000000-0xefffffff]
pci 0000:00:00.0: BAR 8: assigned [mem 0xe1000000-0xe10fffff]
pci 0000:01:00.0: BAR 0: assigned [mem 0xe1000000-0xe100ffff 64bit]
pci 0000:01:00.0: BAR 6: assigned [mem 0xe1010000-0xe101ffff pref]
pci 0000:00:00.0: PCI bridge to [bus 01-0c]
pci 0000:00:00.0:   bridge window [mem 0xe1000000-0xe10fffff]
xilinx-dpdma fd4c0000.dma: Xilinx DPDMA engine is probed
xenfs: not registering filesystem on non-xen platform
Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
ff000000.serial: ttyPS0 at MMIO 0xff000000 (irq = 217, base_baud = 6250000) is a xuartps
console [ttyPS0] enabled
console [ttyPS0] enabled
bootconsole [uart0] disabled
bootconsole [uart0] disabled
ff010000.serial: ttyPS1 at MMIO 0xff010000 (irq = 218, base_baud = 6250000) is a xuartps
Unable to detect cache hierarchy from DT for CPU 0
brd: module loaded
loop: module loaded
ahci-ceva fd0c0000.ahci: AHCI 0001.0301 32 slots 2 ports 6 Gbps 0x3 impl platform mode
ahci-ceva fd0c0000.ahci: flags: 64bit ncq sntf pm clo only pmp fbs pio slum part ccc sds apst
scsi host0: ahci-ceva
scsi host1: ahci-ceva
ata1: SATA max UDMA/133 mmio [mem 0xfd0c0000-0xfd0c1fff] port 0x100 irq 214
ata2: SATA max UDMA/133 mmio [mem 0xfd0c0000-0xfd0c1fff] port 0x180 irq 214
mtdoops: mtd device (mtddev=name/number) must be supplied
m25p80 spi0.0: found n25q512a, expected m25p80
m25p80 spi0.0: Controller not in SPI_TX_QUAD mode, just use extended SPI mode
m25p80 spi0.0: n25q512a (131072 Kbytes)
8 ofpart partitions found on MTD device spi0.0
Creating 8 MTD partitions on "spi0.0":
0x000000000000-0x000000800000 : "boot"
0x000000800000-0x000000840000 : "bootenv"
0x000000840000-0x000001240000 : "kernel"
0x000001240000-0x000008000000 : "spare"
0x000000000000-0x000000100000 : "qspi-fsbl-uboot"
0x000000100000-0x000000600000 : "qspi-linux"
0x000000600000-0x000000620000 : "qspi-device-tree"
0x000000620000-0x000000c00000 : "qspi-rootfs"
libphy: Fixed MDIO Bus: probed
CAN device driver interface
libphy: MACB_mii_bus: probed
macb ff0e0000.ethernet eth0: Cadence GEM rev 0x50070106 at 0xff0e0000 irq 29 (00:0a:35:00:22:01)
macb ff0e0000.ethernet eth0: attached PHY driver [Generic PHY] (mii_bus:phy_addr=ff0e0000.etherne:0c, irq=-1)
tg3.c:v3.137 (May 11, 2014)
pci 0000:00:00.0: enabling device (0000 -> 0002)
 

Broadcom NIC card probing

tg3 0000:01:00.0: enabling device (0000 -> 0002)
tg3 0000:01:00.0 eth1: Tigon3 [partno(BCM95751A519FLP) rev 4201] (PCI Express) MAC address 00:10:18:32:d2:a9
tg3 0000:01:00.0 eth1: attached PHY is 5750 (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[0])
tg3 0000:01:00.0 eth1: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[0] TSOcap[1]
tg3 0000:01:00.0 eth1: dma_rwctrl[76180000] dma_mask[64-bit]

lspci output

root@Xilinx: lspci
00:00.0 PCI bridge: Xilinx Corporation Device d022
01:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5751 Gigabit Ethernet PCI Express (rev 21)

Ethernet Interface

root@Xilinx: ifconfig -a eth1
eth1     Link encap:Ethernet  HWaddr 00:10:18:32:D2:A9
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:222

Testing of Ethernet interface

root@Xilinx: ifconfig eth1 192.168.1.2
root@Xilinx: IPv6: ADDRCONF(NETDEV_UP): eth1: link is not ready
 tg3 0000:01:00.0 eth1: Link is up at 1000 Mbps, full duplex
 tg3 0000:01:00.0 eth1: Flow control is on for TX and on for RX
 IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
root@Xilinx:
root@Xilinx: ping 192.168.1.4
PING 192.168.1.4 (192.168.1.4): 56 data bytes
64 bytes from 192.168.1.4: seq=0 ttl=128 time=0.794 ms
64 bytes from 192.168.1.4: seq=1 ttl=128 time=0.655 ms
64 bytes from 192.168.1.4: seq=2 ttl=128 time=0.670 ms
64 bytes from 192.168.1.4: seq=3 ttl=128 time=0.354 ms
64 bytes from 192.168.1.4: seq=4 ttl=128 time=0.918 ms
64 bytes from 192.168.1.4: seq=5 ttl=128 time=0.724 ms
64 bytes from 192.168.1.4: seq=6 ttl=128 time=0.719 ms
64 bytes from 192.168.1.4: seq=7 ttl=128 time=0.712 ms
--- 192.168.1.4 ping statistics ---
27 packets transmitted, 27 packets received, 0% packet loss
round-trip min/avg/max = 0.354/0.652/0.918 ms
root@Xilinx:

MSI Interrupts

root@Xilinx-ZCU102-2016_3:~# cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
  1:          0          0          0          0     GICv2  29 Edge      arch_timer
  2:       9636       8431       7931       9452     GICv2  30 Edge      arch_timer
 12:          0          0          0          0     GICv2 156 Level     zynqmp-dma
 13:          0          0          0          0     GICv2 157 Level     zynqmp-dma
 14:          0          0          0          0     GICv2 158 Level     zynqmp-dma
 15:          0          0          0          0     GICv2 159 Level     zynqmp-dma
 16:          0          0          0          0     GICv2 160 Level     zynqmp-dma
 17:          0          0          0          0     GICv2 161 Level     zynqmp-dma
 18:          0          0          0          0     GICv2 162 Level     zynqmp-dma
 19:          0          0          0          0     GICv2 163 Level     zynqmp-dma
 20:          0          0          0          0     GICv2 164 Level     Mali_GP_MMU, Mali_GP, Mali_PP0_MMU, Mali_PP0, Mali_PP1_MMU, Mali_PP1
 30:          0          0          0          0     GICv2  95 Level     eth0, eth0
206:        302          0          0          0     GICv2  49 Level     cdns-i2c
207:         40          0          0          0     GICv2  50 Level     cdns-i2c
209:          0          0          0          0     GICv2 150 Level     nwl_pcie:misc
214:         15          0          0          0     GICv2  47 Level     ff0f0000.spi
215:          0          0          0          0     GICv2  58 Level     ffa60000.rtc
216:          0          0          0          0     GICv2  59 Level     ffa60000.rtc
217:          0          0          0          0     GICv2 165 Level     ahci-ceva[fd0c0000.ahci]
219:          0          0          0          0     GICv2 187 Level     arm-smmu global fault
220:        882          0          0          0     GICv2  53 Level     xuartps
223:          0          0          0          0     GICv2 154 Level     fd4c0000.dma
225:        408          0          0          0  nwl_pcie:msi 524288 Edge      eth1
226:          0          0          0          0     GICv2  97 Level     xhci-hcd:usb1
IPI0:      1040       1287        627       1142       Rescheduling interrupts
IPI1:        59         46         56         80       Function call interrupts
IPI2:         0          0          0          0       CPU stop interrupts
IPI3:         0          0          0          0       Timer broadcast interrupts
IPI4:         0          0          0          0       IRQ work interrupts
IPI5:         0          0          0          0       CPU wake-up interrupts
Err:          0
Note:
AER services with PS PCIe as Root Port have not been tested yet.

Related Links