From a1facc1fffc17a65e2c12a8de7434b9325ec0324 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 20 Jul 2020 15:08:24 -0700 Subject: ACPI: NFIT: Add runtime firmware activate support Plumb the platform specific backend for the generic libnvdimm firmware activate interface. Register dimm level operations to arm/disarm activation, and register bus level operations to report the dynamic platform-quiesce time relative to the number of dimms armed for firmware activation. A new nfit-specific bus attribute "firmware_activate_noidle" is added to allow the activation to switch between platform enforced, and OS opportunistic device quiesce. In other words, let the hibernate cycle handle in-flight device-dma rather than the platform attempting to increase PCI-E timeouts and the like. Cc: Dave Jiang Cc: Ira Weiny Cc: Vishal Verma Signed-off-by: Dan Williams Signed-off-by: Vishal Verma --- Documentation/ABI/testing/sysfs-bus-nfit | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-bus-nfit b/Documentation/ABI/testing/sysfs-bus-nfit index a1cb44dcb908..e4f76e7eab93 100644 --- a/Documentation/ABI/testing/sysfs-bus-nfit +++ b/Documentation/ABI/testing/sysfs-bus-nfit @@ -202,6 +202,25 @@ Description: functions. See the section named 'NVDIMM Root Device _DSMs' in the ACPI specification. +What: /sys/bus/nd/devices/ndbusX/nfit/firmware_activate_noidle +Date: Apr, 2020 +KernelVersion: v5.8 +Contact: linux-nvdimm@lists.01.org +Description: + (RW) The Intel platform implementation of firmware activate + support exposes an option let the platform force idle devices in + the system over the activation event, or trust that the OS will + do it. The safe default is to let the platform force idle + devices since the kernel is already in a suspend state, and on + the chance that a driver does not properly quiesce bus-mastering + after a suspend callback the platform will handle it. However, + the activation might abort if, for example, platform firmware + determines that the activation time exceeds the max PCI-E + completion timeout. Since the platform does not know whether the + OS is running the activation from a suspend context it aborts, + but if the system owner trusts driver suspend callback to be + sufficient then 'firmware_activation_noidle' can be + enabled to bypass the activation abort. What: /sys/bus/nd/devices/regionX/nfit/range_index Date: Jun, 2015 -- cgit v1.2.3