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authorDan Williams <dan.j.williams@intel.com>2020-07-21 01:08:24 +0300
committerVishal Verma <vishal.l.verma@intel.com>2020-07-29 04:29:22 +0300
commita1facc1fffc17a65e2c12a8de7434b9325ec0324 (patch)
tree1b12e0e5e163bb3a4f8adcb0344c9f5a36801a1e /Documentation
parent48001ea50d17f3eb06a552e9ecf21f7fc01b25da (diff)
downloadlinux-a1facc1fffc17a65e2c12a8de7434b9325ec0324.tar.xz
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 <dave.jiang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-nfit19
1 files changed, 19 insertions, 0 deletions
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