Xavier NX set PCIe Rst

Robotics & Edge Computing Jetson & Embedded Systems Jetson Xavier NX
1

Hello everyone,
I would like to reset a PCIe Device ( an NVMe connected to PCIE0 on a custom carrier board ) . I read online, that this should be possible by removing and rescaning the pcie device ( How to Reset/Cycle Power to a PCIe Device? - Unix & Linux Stack Exchange ).

I tried that but the PCIE_RST pin on the Xavier NX was not set. No matter what I tried, the reset was not asserted. It stayed high. The only time I found the pin changed was at boot when the reset was deasserted.

Is that the intended behaviour? Is there a way to assert the PCIE_RST by hand?

Thanks

Johannes

3

Setting the reset sysfs command did not set the PCIe Rst either.

$ lspci
0004:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad1 (rev a1)
0004:01:00.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
0004:02:01.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
0004:02:02.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
0004:02:03.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
0004:03:00.0 RAM memory: Xilinx Corporation Device d021
0004:04:00.0 Network controller: Qualcomm Atheros QCA6174 802.11ac Wireless Network Adapter (rev 32)
0005:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad0 (rev a1)
0005:01:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981

$ sudo sh -c "echo 1 > /sys/bus/pci/devices/0005\:01\:00.0/reset"
5

Sorry for the late response, is this still an issue to support? Thanks

6

Hello, thanks for coming back on that issue. Yes it is. We think it is necessary to reset a PCIe switch after a NVMe connected to that switch was swapped. Right now we have no solution other than to reset the whole system which is not an option for the finished product.

Thanks

1 Like
9

Hi,

Tegra PCIe doesn’t support hotplug, so rescan/reset sysfs nodes won’t work.
Instead, you can unbind and bind Tegra PCIe platform driver.

Below example is for M.2 Key M slot in Jetson NX board.
cd /sys/bus/platform/drivers/tegra-pcie-dw
echo 141a0000.pcie > unbind
echo 141a0000.pcie > bind

Thanks,
Manikanta

11

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