Add static inline stubs for init_clock_gating.h functions
so that we don't need ifdefs in the actual code. We already
have one in intel_display_power.c, and now I need to bring
over intel_display_reset.c.

Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260415210411.24750-6-ville.syrjala@linux.intel.com

topic/step to unify xe and i915 on common steppings header and enum

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

From: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/cc1ff0a476ff457e88251e22b83c1a45ada11ecc@intel.com

Instead of using the proxy intel_step.h in display, just include the
common step file directly where needed. This allows us to remove the
compat intel_step.h header.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patch.msgid.link/83b5f13b7f863b9cbc61499bcff22af5cd822a0b.1774875688.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Use the shared stepping enums from include/drm/intel/step.h.

For now, define xe_step as intel_step to avoid mass renames at the same
time. For compat, we can remove the reverse macro.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patch.msgid.link/8173d9d753b343ba127d86277344248a6b1d0c3f.1774875688.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Since the PCI registers are used from both i915 display and core, move
intel_pci_config.h to include/drm/intel/pci_config.h. Drop the intel_
prefix from the name to reduce tautology.

With this, we can drop the corresponding xe display compat header.

v2: Rebase

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/5aac6c711c3f0a09fc52f322455a4a4b35f80a82.1775590536.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Since the mchbar registers are used from both i915 display and core,
move intel_mchbar_regs.h to include/drm/intel/mchbar_regs.h. Drop the
intel_ prefix from the name to reduce tautology.

With this, we can drop the corresponding xe display compat header.

v2: Rebase

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/6c951b2c05db74ea517d52a3912986f7eb886422.1775590536.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Move vlv_iosf_sb_reg.h to include/drm/intel/vlv_iosf_sb_regs.h. Use
_regs.h suffix to align better with other register headers. Move enum
vlv_iosf_sb_unit there as well, breaking the final include tie related
to IOSF sideband between display and i915 core.

With this, we can completely remove the xe compat vls_iosf_sb*.h
headers.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/41b060b0d6453de39ca775eab10ee12b25c45b7d.1774957233.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

The plan is to move all the mmio stuff into the display code itself.
As a first step implement the register polling in intel_de.c.

Currently i915 and xe implement this stuff in slightly different
ways, so there are some functional changes here. Try to go for a
reasonable middle ground between the i915 and xe implementations:
- the exponential backoff limit is the simpler approach taken
  by i915 (== just clamp the max sleep duration to 1 ms)
- the fast vs. slow timeout handling is similar to i915 where
  we first try the fast timeout and then again the slow timeout
  if the condition still isn't satisfied. xe just adds up the
  timeouts together, which is a bit weird.
- the atomic wait variant uses udelay() like xe, whereas i915
  has no udelay()s in its atomic loop. As a compromise go for a
  fixed 1 usec delay  for short waits, instead of the somewhat
  peculiar xe behaviour where it effectively just does one
  iteration of the loop.
- keep the "use udelay() for < 10 usec waits" logic (which
  more or less mirrors fsleep()), but include an explicit
  might_sleep() even for these short waits when called from
  a non-atomic intel_de_wait*() function. This should prevent
  people from calling the non-atomic functions from the wrong
  place.

Eventually we may want to switch over to poll_timeout*(),
but that lacks the exponential backoff, so a bit too
radical to change in one go.

v2: Initialize ret in intel_de_wait_for_register() to avoid a
    warning from the compiler. This is actually a false positive
    since we always have fast_timeout_us!=0 when slow_timeout_us!=0,
    but the compiler can't see that

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260323094304.8171-1-ville.syrjala@linux.intel.com

As there are no more compat users left for intel_step_name(), remove the
macro and use the more direct include for the enumerations.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://patch.msgid.link/816e3f6dda0a112392e8f8ccff820a81aff63f32.1773663208.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Add a shared header that's used by i915, xe, and i915 display.

This allows us to drop the compat-i915-headers/i915_reg_defs.h include
from xe_reg_defs.h. All the register macro helpers were subtly pulled in
from i915 to all of xe through this.

Reviewed-by: Michał Grzelak <michal.grzelak@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/fcd70f3317755bf98a6e7ae88974aa8ba06efd1e.1772042022.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>