[PATCH v8 0/3] drm/xe/sysctrl: Add System Controller debugfs

["Anoop, Vijay" <anoop.c.vijay@intel.com>]

From: Anoop Vijay <anoop.c.vijay@intel.com>

This series adds debugfs-based test interfaces for the System
Controller (sysctrl) mailbox, to aid validation of firmware
communication and RAS error handling without requiring userspace
tooling.

Key features introduced:
- Debugfs infrastructure for sysctrl (types, registration hook)
- Loopback test entry exercising the mailbox send/receive path via
  the Core group's inverted loopback command (0xFF/0x03)
- RAS error injection entry exercising the Diag group's
  RAS_ERR_INJECT command (0x02/0x7E), gated on the diag application
  having completed firmware boot/init
- Generic mailbox passthrough entry for any group/command not
  covered by a dedicated entry

v8 (Rodrigo, Sashiko AI):
- Tighten debugfs permissions to 0600
- Fix multi-space mailbox token parsing
- Tighten mailbox response-length validation

v7:
- Add per-command timeout override to mailbox debugfs
- Add per-command response-length override to mailbox debugfs
- Add usage hint to loopback debugfs output
- Default mailbox response capacity to XE_SYSCTRL_MB_MAX_DATA_SIZE
  (accounting for the mailbox header size) instead of
  XE_SYSCTRL_MB_MAX_MESSAGE_SIZE
- Reject resplen=0 and skip empty tokens after timeout= so a
  resplen= separated by multiple spaces is still recognized
  (Sashiko AI)

v6 (Rodrigo):
- Reject non-zero offset writes for loopback, mailbox, and ras_error_inject entries
- Account for mailbox header size when validating input payload length
- Add warning on devm_mutex_init() registration failures
- Refactor token parsing to simplify cleanup and error handling

v5:
- Drop the application-status patch; already landed upstream
- Add per-entry locking for debugfs accesses
- Add xe_pm_runtime guards for ras_error_inject readiness checks
- Simplify ras_error_inject write-path flow
- Skip empty mailbox group/command tokens
- Drop unused xe_device.h include

v4 (Rodrigo, Anshuman):
- Added lore links to the parent application-status series
- Squashed debugfs infrastructure and loopback support into a single commit
- Gated ras_error_inject on diag firmware readiness in .open()
- Added a generic mailbox debugfs entry

v3:
- Fix RAS error injection command ID to 0x7E
- Add xe_pm_runtime guard for mailbox commands
- Rename error injection command to avoid fwctl command ID collision
- Reject writes until the diag firmware is ready


Anoop Vijay (3):
  drm/xe/sysctrl: Add sysctrl debugfs infrastructure and loopback test
    interface
  drm/xe/sysctrl: Add RAS error injection debugfs interface
  drm/xe/sysctrl: Add generic mailbox passthrough debugfs entry

 drivers/gpu/drm/xe/Makefile                   |   1 +
 drivers/gpu/drm/xe/xe_debugfs.c               |   4 +
 drivers/gpu/drm/xe/xe_sysctrl_debugfs.c       | 500 ++++++++++++++++++
 drivers/gpu/drm/xe/xe_sysctrl_debugfs.h       |  14 +
 drivers/gpu/drm/xe/xe_sysctrl_mailbox_types.h |  37 ++
 drivers/gpu/drm/xe/xe_sysctrl_types.h         |  47 ++
 6 files changed, 603 insertions(+)
 create mode 100644 drivers/gpu/drm/xe/xe_sysctrl_debugfs.c
 create mode 100644 drivers/gpu/drm/xe/xe_sysctrl_debugfs.h

-- 
2.43.0