How to monitor the SSD status

Version:
root@localhost:/sys/kernel/config/pci_ep# uname -a
Linux localhost.localdomain 5.10.104-tegra #9 SMP PREEMPT Mon Nov 7 19:50:38 CST 2022 aarch64 aarch64 aarch64 GNU/Linux
Question:
Now I want to monitor the SSD status by reading the PCIE register status.Becase I want to control the LED blinking according to the SSD status(For example.Unplug or plug.start or stop.data transfered or not) by using a GPIO.How can I add code into file “tegra194-pcie.c”.Can you give me an example or flow?

I have no idea about use case, may other developers help to share experiences.