drm/i915/guc: Disable PL1 power limit when loading GuC firmware

On dGfx, the PL1 power limit being enabled and set to a low value results
in a low GPU operating freq. It also negates the freq raise operation which
is done before GuC firmware load. As a result GuC firmware load can time
out. Such timeouts were seen in the GL #8062 bug below (where the PL1 power
limit was enabled and set to a low value). Therefore disable the PL1 power
limit when allowed by HW when loading GuC firmware.

v2:
- Take mutex (to disallow writes to power1_max) across GuC reset/fw load
- Add hwm_power_max_restore to error return code path

v3 (Jani N):
- Add/remove explanatory comments
- Function renames
- Type corrections
- Locking annotation

v4:
- Don't hold the lock across GuC reset (Rodrigo)
- New locking scheme (suggested by Rodrigo)
- Eliminate rpm_get in power_max_disable/restore, not needed (Tvrtko)

v5:
- Fix uninitialized pl1en variable compile warning reported by kernel
build robot by creating new err_rps label

Link: https://gitlab.freedesktop.org/drm/intel/-/issues/8062
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230420164041.1428455-3-ashutosh.dixit@intel.com

drm/i915/hwmon: Add HWMON infrastructure

The i915 HWMON module will be used to expose voltage, power and energy
values for dGfx. Here we set up i915 hwmon infrastructure including i915
hwmon registration, basic data structures and functions.

v2:
- Create HWMON infra patch (Ashutosh)
- Fixed review comments (Jani)
- Remove "select HWMON" from i915/Kconfig (Jani)
v3: Use hwm_ prefix for static functions (Ashutosh)
v4: s/#ifdef CONFIG_HWMON/#if IS_REACHABLE(CONFIG_HWMON)/ since the former
doesn't work if hwmon is compiled as a module (Guenter)
v5: Fixed review comments (Jani)
v6: s/kzalloc/devm_kzalloc/ (Andi)
v7: s/hwmon_device_register_with_info/
devm_hwmon_device_register_with_info/ (Ashutosh)

Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Dale B Stimson <dale.b.stimson@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221013154526.2105579-2-ashutosh.dixit@intel.com