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author | Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com> | 2018-12-19 03:02:27 +0300 |
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committer | Joel Stanley <joel@jms.id.au> | 2019-03-20 07:43:33 +0300 |
commit | 16e45c190ffdac3668ba28561e3513ec085941cb (patch) | |
tree | d707bd18f0bbf0bfff92b66cd9ee224d57b4330d /include/uapi/linux/if_fc.h | |
parent | 4c63c4213e417b09f48c9d9bcd115916c0054bee (diff) | |
download | linux-16e45c190ffdac3668ba28561e3513ec085941cb.tar.xz |
peci: Add support for PECI bus driver core
This commit adds driver implementation for PECI bus core into linux
driver framework.
PECI (Platform Environment Control Interface) is a one-wire bus interface
that provides a communication channel from Intel processors and chipset
components to external monitoring or control devices. PECI is designed to
support the following sideband functions:
* Processor and DRAM thermal management
- Processor fan speed control is managed by comparing Digital Thermal
Sensor (DTS) thermal readings acquired via PECI against the
processor-specific fan speed control reference point, or TCONTROL. Both
TCONTROL and DTS thermal readings are accessible via the processor PECI
client. These variables are referenced to a common temperature, the TCC
activation point, and are both defined as negative offsets from that
reference.
- PECI based access to the processor package configuration space provides
a means for Baseboard Management Controllers (BMC) or other platform
management devices to actively manage the processor and memory power
and thermal features.
* Platform Manageability
- Platform manageability functions including thermal, power, and error
monitoring. Note that platform 'power' management includes monitoring
and control for both the processor and DRAM subsystem to assist with
data center power limiting.
- PECI allows read access to certain error registers in the processor MSR
space and status monitoring registers in the PCI configuration space
within the processor and downstream devices.
- PECI permits writes to certain registers in the processor PCI
configuration space.
* Processor Interface Tuning and Diagnostics
- Processor interface tuning and diagnostics capabilities
(Intel Interconnect BIST). The processors Intel Interconnect Built In
Self Test (Intel IBIST) allows for infield diagnostic capabilities in
the Intel UPI and memory controller interfaces. PECI provides a port to
execute these diagnostics via its PCI Configuration read and write
capabilities.
* Failure Analysis
- Output the state of the processor after a failure for analysis via
Crashdump.
PECI uses a single wire for self-clocking and data transfer. The bus
requires no additional control lines. The physical layer is a self-clocked
one-wire bus that begins each bit with a driven, rising edge from an idle
level near zero volts. The duration of the signal driven high depends on
whether the bit value is a logic '0' or logic '1'. PECI also includes
variable data transfer rate established with every message. In this way, it
is highly flexible even though underlying logic is simple.
The interface design was optimized for interfacing between an Intel
processor and chipset components in both single processor and multiple
processor environments. The single wire interface provides low board
routing overhead for the multiple load connections in the congested routing
area near the processor and chipset components. Bus speed, error checking,
and low protocol overhead provides adequate link bandwidth and reliability
to transfer critical device operating conditions and configuration
information.
This implementation provides the basic framework to add PECI extensions to
the Linux bus and device models. A hardware specific 'Adapter' driver can
be attached to the PECI bus to provide sideband functions described above.
It is also possible to access all devices on an adapter from userspace
through the /dev interface. A device specific 'Client' driver also can be
attached to the PECI bus so each processor client's features can be
supported by the 'Client' driver through an adapter connection in the bus.
OpenBMC-Staging-Count: 2
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Haiyue Wang <haiyue.wang@linux.intel.com>
Reviewed-by: James Feist <james.feist@linux.intel.com>
Reviewed-by: Vernon Mauery <vernon.mauery@linux.intel.com>
[joel: Fix access_ok usage for 5.0]
Signed-off-by: Joel Stanley <joel@jms.id.au>
Diffstat (limited to 'include/uapi/linux/if_fc.h')
0 files changed, 0 insertions, 0 deletions