[RFC,0/3] add SW BOOST support for CPPC

Message

Xiongfeng Wang May 8, 2020, 9:11 a.m. UTC

ACPI spec 6.2 section 8.4.7.1 provide the following two CPC registers.

"Highest performance is the absolute maximum performance an individual
processor may reach, assuming ideal conditions. This performance level
may not be sustainable for long durations, and may only be achievable if
other platform components are in a specific state; for example, it may
require other processors be in an idle state.

Nominal Performance is the maximum sustained performance level of the
processor, assuming ideal operating conditions. In absence of an
external constraint (power, thermal, etc.) this is the performance level
the platform is expected to be able to maintain continuously. All
processors are expected to be able to sustain their nominal performance
state simultaneously."

We can use Highest Performance as the max performance in boost mode and
Nomial Performance as the max performance in non-boost mode. If the
Highest Performance is greater than the Nominal Performance, we assume
SW BOOST is supported.

Xiongfeng Wang (3):
  cpufreq: fix the return value in 'cpufreq_boost_set_sw()'
  cpufreq: Add SW BOOST support for drivers without frequency table
  CPPC: add support for SW BOOST

 drivers/cpufreq/cppc_cpufreq.c | 17 +++++++++++++++--
 drivers/cpufreq/cpufreq.c      | 25 +++++++++++++++++--------
 include/linux/cpufreq.h        |  2 ++
 3 files changed, 34 insertions(+), 10 deletions(-)