This commit implements T264 ISP floorsweeping functionality in the Linux
kernel driver, extending the existing RCE firmware implementation to
provide transparent ISP unit redirection at the kernel level.
Changes:
- Add isp_capture_query_availability_mask_probe() function to query ISP
availability mask from RCE firmware during driver probe via IVC
- Add isp_capture_find_first_available() helper function to find the
first available ISP unit from a bitmask for HW assignment
- Integrate floorsweeping logic into isp_get_nvhost_device() to handle
SW-to-HW ISP unit mapping with thread-safe assignment
- Add isp_capture_get_capabilities() function to expose ISP availability
to userspace via new IOCTL (ISP_CAPTURE_GET_CAPABILITIES)
- Add probe-time caching of ISP availability mask to avoid repeated IVC
queries during runtime
- Add comprehensive error handling and safety mechanisms for unknown
configurations
Implementation details:
- Uses CAPTURE_ISP_FUSE_QUERY_REQ/RESP IVC messages for querying RCE
- Maintains SW-to-HW ISP unit mapping array protected by mutex
- The SW-to-HW mappings persist for the driver's lifetime, given that
multiple channels make use of the same SW unit ID's and we do not
have tracking of all open channels during runtime
- Integrates with existing ISP setup flow before buffer allocation
- Maintains backward compatibility with non-T264 hardware
- Conservative approach: blocks requests when no ISP units are available
Floorsweeping logic (handled by RCE firmware, exposed as bitmask):
- Mask bit N set = ISP N available (not fused off)
- Mask bit N clear = ISP N fused off (unavailable)
- Examples:
- 0x3 (0b11): Both ISP0/ISP1 available (no floorsweeping)
- 0x1 (0b01): Only ISP0 available → all requests map to ISP0
- 0x2 (0b10): Only ISP1 available → all requests map to ISP1
- 0x0: No ISP units available (block all requests)
Benefits:
- Transparent operation for applications using fusacapture library
- Automatic ISP unit redirection without API changes
- Improved hardware yield by supporting single-ISP configurations
- Robust error handling and safety mechanisms
- Minimal performance overhead with probe-time caching
The implementation complements the existing RCE firmware floorsweeping
support and provides a complete end-to-end solution for T264 ISP
floorsweeping across all software layers.
Bug 5640706
Change-Id: If85ee3178e857394300479dd42e636f5f5d3bd23
Signed-off-by: fraunak <fraunak@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3491180
GVS: buildbot_gerritrpt <buildbot_gerritrpt@nvidia.com>
Reviewed-by: Evgeny Kornev <ekornev@nvidia.com>
Reviewed-by: Kalle Jokiniemi <kjokiniemi@nvidia.com>
Reviewed-by: Semi Malinen <smalinen@nvidia.com>
Tested-by: Akihiro Mizusawa <amizusawa@nvidia.com>
