Changes since v2 [1]: - Drop the "mem-quiet" pm-debug interface in favor of an explicit hibernate_quiet_exec() helper that executes firmware activation, or any other subsystem provided routine, in a system-quiet context. (Rafael)
- Rework the sysfs interface to add an explicit trigger to run activation under hibernate_quiet_exec(). Rename ndbusX/firmware_activate to ndbusX/firmware/activate, and add a ndbusX/firmware/capability. Some ndctl reworks are needed to catch up with this change.
- The new ndbusX/firmware/capability attribute indicates the default activation method / execution context between "live" and "suspend".
[1]: http://lore.kernel.org/r/159408711335.2385045.2567600405906448375.stgit@dwil...
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Quoting the documentation:
Some persistent memory devices run a firmware locally on the device / "DIMM" to perform tasks like media management, capacity provisioning, and health monitoring. The process of updating that firmware typically involves a reboot because it has implications for in-flight memory transactions. However, reboots are disruptive and at least the Intel persistent memory platform implementation, described by the Intel ACPI DSM specification [1], has added support for activating firmware at runtime.
[1]: https://docs.pmem.io/persistent-memory/
The approach taken is to abstract the Intel platform specific mechanism behind a libnvdimm-generic sysfs interface. The interface could support runtime-firmware-activation on another architecture without need to change userspace tooling.
The ACPI NFIT implementation involves a set of device-specific-methods (DSMs) to 'arm' individual devices for activation and bus-level 'trigger' method to execute the activation. Informational / enumeration methods are also provided at the bus and device level.
One complicating aspect of the memory device firmware activation is that the memory controller may need to be quiesced, no memory cycles, during the activation. While the platform has mechanisms to support holding off in-flight DMA during the activation, the device response to that delay is potentially undefined. The platform may reject a runtime firmware update if, for example a PCI-E device does not support its completion timeout value being increased to meet the activation time. Outside of device timeouts the quiesce period may also violate application timeouts.
Given the above device and application timeout considerations the implementation uses a new hibernate_quiet_exec() facility to carry-out firmware activation. This imposes the same conditions that allow for a stable memory image snapshot to be taken for a hibernate-to-disk sequence. However, if desired, runtime activation without the hibernate freeze can be forced as an override.
The ndctl utility grows the following extensions / commands to drive this mechanism:
1/ The existing update-firmware command will 'arm' devices where the firmware image is staged by default.
ndctl update-firmware all -f firmware_image.bin
2/ The existing ability to enumerate firmware-update capabilities now includes firmware activate capabilities at the 'bus' and 'dimm/device' level:
ndctl list -BDF -b nfit_test.0 [ { "provider":"nfit_test.0", "dev":"ndbus2", "scrub_state":"idle", "firmware":{ "activate_method":"suspend", "activate_state":"idle" }, "dimms":[ { "dev":"nmem1", "id":"cdab-0a-07e0-ffffffff", "handle":0, "phys_id":0, "security":"disabled", "firmware":{ "current_version":0, "can_update":true } }, ...
3/ The new activate-firmware command triggers firmware activation per the platform enumerated context, "suspend" vs "live", or can be forced to "live" if there is a explicit knowledge that allowing applications and devices to race the quiesce timeout will have no adverse effects.
ndctl activate-firmware nfit_test.0 [--force]
These patches are passing an updated version of the ndctl "firmware-update.sh" unit test (to be posted).
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Dan Williams (11): libnvdimm: Validate command family indices ACPI: NFIT: Move bus_dsm_mask out of generic nvdimm_bus_descriptor ACPI: NFIT: Define runtime firmware activation commands tools/testing/nvdimm: Cleanup dimm index passing tools/testing/nvdimm: Add command debug messages tools/testing/nvdimm: Prepare nfit_ctl_test() for ND_CMD_CALL emulation tools/testing/nvdimm: Emulate firmware activation commands driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW} libnvdimm: Convert to DEVICE_ATTR_ADMIN_RO() PM, libnvdimm: Add runtime firmware activation support ACPI: NFIT: Add runtime firmware activate support
Documentation/ABI/testing/sysfs-bus-nfit | 19 + Documentation/ABI/testing/sysfs-bus-nvdimm | 2 .../driver-api/nvdimm/firmware-activate.rst | 86 ++++ drivers/acpi/nfit/core.c | 142 +++++-- drivers/acpi/nfit/intel.c | 386 ++++++++++++++++++++ drivers/acpi/nfit/intel.h | 61 +++ drivers/acpi/nfit/nfit.h | 38 ++ drivers/nvdimm/bus.c | 16 + drivers/nvdimm/core.c | 149 ++++++++ drivers/nvdimm/dimm_devs.c | 119 ++++++ drivers/nvdimm/namespace_devs.c | 2 drivers/nvdimm/nd-core.h | 1 drivers/nvdimm/pfn_devs.c | 2 drivers/nvdimm/region_devs.c | 2 include/linux/device.h | 4 include/linux/libnvdimm.h | 52 +++ include/linux/suspend.h | 6 include/linux/sysfs.h | 7 include/uapi/linux/ndctl.h | 5 kernel/power/hibernate.c | 97 +++++ tools/testing/nvdimm/test/nfit.c | 367 +++++++++++++++---- 21 files changed, 1449 insertions(+), 114 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-bus-nvdimm create mode 100644 Documentation/driver-api/nvdimm/firmware-activate.rst
base-commit: 48778464bb7d346b47157d21ffde2af6b2d39110