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* [PATCH v5 0/3] PCI: cadence: Add LTSSM debugfs
@ 2026-05-15 14:57 Hans Zhang
  2026-05-15 14:57 ` [PATCH v5 1/3] PCI: cadence: Add HPA architecture flag Hans Zhang
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Hans Zhang @ 2026-05-15 14:57 UTC (permalink / raw)
  To: bhelgaas, lpieralisi, kwilczynski, mani, hans.zhang
  Cc: robh, mpillai, a-garg7, s-vadapalli, linux-pci, linux-kernel,
	Hans Zhang

Hi,

This series adds debugfs support to the Cadence PCIe controller driver,
allowing users to read the current LTSSM state of the link for debugging
purposes.

Patch 1 introduces a new flag 'is_hpa' in the cdns_pcie structure to
distinguish HPA (High Performance Architecture) IP platforms from LGA
(Legacy Architecture) IP platforms, as they have different register
layouts for LTSSM status.

Patch 2 implements the debugfs file "ltssm_status" for HPA IP under a
per-device directory. It reads the LTSSM state from the appropriate
hardware register based on the 'is_hpa' flag and displays both a
descriptive string and the raw value.

Patch 3 adds LTSSM debugfs support for LGA IP, utilizing a new callback
'get_lga_ltssm' in cdns_pcie_ops to read the LTSSM state from the LGA
register. The debugfs interface now supports both IP types seamlessly.

=====================
Test:
root@orangepi6plus:~# ls -l /sys/kernel/debug/cdns_pcie_a0*
/sys/kernel/debug/cdns_pcie_a010000.pcie:
total 0
-r--r--r-- 1 root root 0 Jan  1  1970 ltssm_status

/sys/kernel/debug/cdns_pcie_a0c0000.pcie:
total 0
-r--r--r-- 1 root root 0 Jan  1  1970 ltssm_status

/sys/kernel/debug/cdns_pcie_a0e0000.pcie:
total 0
-r--r--r-- 1 root root 0 Jan  1  1970 ltssm_status
root@orangepi6plus:~# 
root@orangepi6plus:~# 
root@orangepi6plus:~# cat /sys/kernel/debug/cdns_pcie_a0*/ltss*
L0_STATE (0x29)
L0_STATE (0x29)
L0_STATE (0x29)
root@orangepi6plus:~# 
root@orangepi6plus:~# uname -a
Linux orangepi6plus 7.1.0-rc2-00377-gb898336dec53-dirty #43 SMP PREEMPT Fri May  8 11:15:00 CST 2026 aarch64 aarch64 aarch64 GNU/Linux
=====================

---
Changes for v5:
- Split LGA and HPA LTSSM debugfs support into separate patches as they
  have different register definitions and access methods. (Aksh, Manikandan)
- Add cdns_pcie_hpa_host_disable() to properly clean up debugfs on
  removal (Mani)
- Remove redundant copyright email address (Mani)

Changes for v4:
- Remove the copyright email address of the author of pcie-cadence-debugfs.c (Mani)
- Add cdns_pcie_hpa_host_disable() (Mani)
- Use DEFINE_SHOW_ATTRIBUTE() (Mani & Sashiko)

Changes for v3:
https://patchwork.kernel.org/project/linux-pci/patch/20260406103237.1203127-1-18255117159@163.com/

- Export cdns_pcie_debugfs_deinit (Mani)
- pcie-cadence-ep.c pcie-cadence-host.c pci-sky1.c call cdns_pcie_debugfs_deinit

Changes for v2:
https://patchwork.kernel.org/project/linux-pci/patch/20260321033035.3008585-3-18255117159@163.com/

- s/DW_PCIE_LTSSM_NAME/CDNS_PCIE_LTSSM_NAME/
- S/January 2026/March 2026/
- EXPORT_SYMBOL_GPL(cdns_pcie_debugfs_init); // Resolve the following error issues.
  >> ERROR: modpost: "cdns_pcie_debugfs_init" [drivers/pci/controller/cadence/pcie-cadence-host-mod.ko] undefined!
  >> ERROR: modpost: "cdns_pcie_debugfs_init" [drivers/pci/controller/cadence/pcie-cadence-ep-mod.ko] undefined!

v1:
https://patchwork.kernel.org/project/linux-pci/cover/20260315155514.127255-1-18255117159@163.com/

Hans Zhang (3):
  PCI: cadence: Add HPA architecture flag
  PCI: cadence: Add HPA IP debugfs for LTSSM status
  PCI: cadence: Add LGA IP debugfs for LTSSM status

 Documentation/ABI/testing/debugfs-cdns-pcie   |   5 +
 drivers/pci/controller/cadence/Kconfig        |   9 +
 drivers/pci/controller/cadence/Makefile       |   1 +
 drivers/pci/controller/cadence/pci-sky1.c     |   5 +
 .../controller/cadence/pcie-cadence-debugfs.c | 263 ++++++++++++++++++
 .../pci/controller/cadence/pcie-cadence-ep.c  |   3 +
 .../cadence/pcie-cadence-host-hpa.c           |  19 +-
 .../controller/cadence/pcie-cadence-host.c    |   9 +-
 drivers/pci/controller/cadence/pcie-cadence.h | 198 +++++++++++++
 9 files changed, 510 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/ABI/testing/debugfs-cdns-pcie
 create mode 100644 drivers/pci/controller/cadence/pcie-cadence-debugfs.c


base-commit: a293ec25d59dd96309058c70df5a4dd0f889a1e4
-- 
2.34.1


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Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-15 14:57 [PATCH v5 0/3] PCI: cadence: Add LTSSM debugfs Hans Zhang
2026-05-15 14:57 ` [PATCH v5 1/3] PCI: cadence: Add HPA architecture flag Hans Zhang
2026-05-15 14:57 ` [PATCH v5 2/3] PCI: cadence: Add HPA IP debugfs for LTSSM status Hans Zhang
2026-05-15 15:39   ` sashiko-bot
2026-05-15 14:57 ` [PATCH v5 3/3] PCI: cadence: Add LGA " Hans Zhang
2026-05-15 15:57   ` sashiko-bot

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