The intention is to clean up the code and make it look a bit more
consistent.

Mark all unitialized module parameter variables as __read_mostly,
not just one of them. The other parameters are read-mostly too.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This is a cleanup which improves code consistency. Move the force_irq_on
module parameter variable and definition to the same place where we have
variables and definitions for other module parameters.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

By default, all non-POLL C-states are entered with interrupts disabled.

There are 2 ways to make 'intel_idle' enter C-states with interrupts
enabled:
  1. Mark the C-state with the CPUIDLE_FLAG_IRQ_ENABLE flag.
  2. Use the force_irq_on module parameter.

The former is the "proper" way of doing it, it is per-C-state and
per-platform. The latter is for debugging purposes only.

The problem is that intel_idle prints the "forced intel_idle_irq"
message in both cases, even though the former case does not needed
this message, because nothing is forced there. This patch addresses the
problem.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The following C-state flags are currently mutually-exclusive and should not
be combined:
  * IRQ_ENABLE
  * IBRS
  * XSTATE

There is a warning for the situation when the IRQ_ENABLE flag
is combined with the IBRS flag, but no warnings for other combinations.
This is inconsistent and prone to errors.

Improve the situation by adding warnings for all the unexpected
combinations. Add a couple of helpful commentaries too.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Introduce a temporary 'state' variable for referencing the currently
processed C-state in the intel_idle_init_cstates_icpu() function.

This makes code lines shorter and easier to read.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The intel_idle_init_cstates_icpu() function includes a loop that iterates
over every C-state. Inside the loop, the same C-state data is referenced 2
ways:
 1. as cpuidle_state_table[cstate]
 2. as drv->states[drv->state_count] (but it is a copy of #1, not the same
    object).

Make the code be more consistent and easier to read by using only the 2nd
way. So the code structure would be as follows:

 1. Use cpuidle_state_table[cstate]
 2. Copy cpuidle_state_table[cstate] to drv->states[drv->state_count]
 3. Use only drv->states[drv->state_count] from this point.

Note, this change introduces a checkpatch.pl warning (too long line), but it
will be addressed in the next patch.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Substitute 'printk()' with 'pr_info()', because 'intel_idle' already uses
'pr_debug()', so using 'pr_info()' will be more consistent.

In addition to this, this patch addresses  the following checkpatch.pl
warning:
  WARNING: printk() should include KERN_<LEVEL> facility level

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull power management updates from Rafael Wysocki:
 "These add EPP support to the AMD P-state cpufreq driver, add support
  for new platforms to the Intel RAPL power capping driver, intel_idle
  and the Qualcomm cpufreq driver, enable thermal cooling for Tegra194,
  drop the custom cpufreq driver for loongson1 that is not necessary any
  more (and the corresponding cpufreq platform device), fix assorted
  issues and clean up code.

  Specifics:

   - Add EPP support to the AMD P-state cpufreq driver (Perry Yuan, Wyes
     Karny, Arnd Bergmann, Bagas Sanjaya)

   - Drop the custom cpufreq driver for loongson1 that is not necessary
     any more and the corresponding cpufreq platform device (Keguang
     Zhang)

   - Remove "select SRCU" from system sleep, cpufreq and OPP Kconfig
     entries (Paul E. McKenney)

   - Enable thermal cooling for Tegra194 (Yi-Wei Wang)

   - Register module device table and add missing compatibles for
     cpufreq-qcom-hw (Nícolas F. R. A. Prado, Abel Vesa and Luca Weiss)

   - Various dt binding updates for qcom-cpufreq-nvmem and
     opp-v2-kryo-cpu (Christian Marangi)

   - Make kobj_type structure in the cpufreq core constant (Thomas
     Weißschuh)

   - Make cpufreq_unregister_driver() return void (Uwe Kleine-König)

   - Make the TEO cpuidle governor check CPU utilization in order to
     refine idle state selection (Kajetan Puchalski)

   - Make Kconfig select the haltpoll cpuidle governor when the haltpoll
     cpuidle driver is selected and replace a default_idle() call in
     that driver with arch_cpu_idle() to allow MWAIT to be used (Li
     RongQing)

   - Add Emerald Rapids Xeon support to the intel_idle driver (Artem
     Bityutskiy)

   - Add ARCH_SUSPEND_POSSIBLE dependencies for ARMv4 cpuidle drivers to
     avoid randconfig build failures (Arnd Bergmann)

   - Make kobj_type structures used in the cpuidle sysfs interface
     constant (Thomas Weißschuh)

   - Make the cpuidle driver registration code update microsecond values
     of idle state parameters in accordance with their nanosecond values
     if they are provided (Rafael Wysocki)

   - Make the PSCI cpuidle driver prevent topology CPUs from being
     suspended on PREEMPT_RT (Krzysztof Kozlowski)

   - Document that pm_runtime_force_suspend() cannot be used with
     DPM_FLAG_SMART_SUSPEND (Richard Fitzgerald)

   - Add EXPORT macros for exporting PM functions from drivers (Richard
     Fitzgerald)

   - Remove /** from non-kernel-doc comments in hibernation code (Randy
     Dunlap)

   - Fix possible name leak in powercap_register_zone() (Yang Yingliang)

   - Add Meteor Lake and Emerald Rapids support to the intel_rapl power
     capping driver (Zhang Rui)

   - Modify the idle_inject power capping facility to support 100% idle
     injection (Srinivas Pandruvada)

   - Fix large time windows handling in the intel_rapl power capping
     driver (Zhang Rui)

   - Fix memory leaks with using debugfs_lookup() in the generic PM
     domains and Energy Model code (Greg Kroah-Hartman)

   - Add missing 'cache-unified' property in the example for kryo OPP
     bindings (Rob Herring)

   - Fix error checking in opp_migrate_dentry() (Qi Zheng)

   - Let qcom,opp-fuse-level be a 2-long array for qcom SoCs (Konrad
     Dybcio)

   - Modify some power management utilities to use the canonical ftrace
     path (Ross Zwisler)

   - Correct spelling problems for Documentation/power/ as reported by
     codespell (Randy Dunlap)"

* tag 'pm-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (53 commits)
  Documentation: amd-pstate: disambiguate user space sections
  cpufreq: amd-pstate: Fix invalid write to MSR_AMD_CPPC_REQ
  dt-bindings: opp: opp-v2-kryo-cpu: enlarge opp-supported-hw maximum
  dt-bindings: cpufreq: qcom-cpufreq-nvmem: make cpr bindings optional
  dt-bindings: cpufreq: qcom-cpufreq-nvmem: specify supported opp tables
  PM: Add EXPORT macros for exporting PM functions
  cpuidle: psci: Do not suspend topology CPUs on PREEMPT_RT
  MIPS: loongson32: Drop obsolete cpufreq platform device
  powercap: intel_rapl: Fix handling for large time window
  cpuidle: driver: Update microsecond values of state parameters as needed
  cpuidle: sysfs: make kobj_type structures constant
  cpuidle: add ARCH_SUSPEND_POSSIBLE dependencies
  PM: EM: fix memory leak with using debugfs_lookup()
  PM: domains: fix memory leak with using debugfs_lookup()
  cpufreq: Make kobj_type structure constant
  cpufreq: davinci: Fix clk use after free
  cpufreq: amd-pstate: avoid uninitialized variable use
  cpufreq: Make cpufreq_unregister_driver() return void
  OPP: fix error checking in opp_migrate_dentry()
  dt-bindings: cpufreq: cpufreq-qcom-hw: Add SM8550 compatible
  ...

Emerald Rapids (EMR) is the next Intel Xeon processor after Sapphire
Rapids (SPR).

EMR C-states are the same as SPR C-states, and we expect that EMR
C-state characteristics (latency and target residency) will be the
same as in SPR. Therefore, add EMR support by using SPR C-states table.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

For testing purposes.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195541.967699392@infradead.org