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From:   Mauro Carvalho Chehab <mchehab@kernel.org>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        "Rodrigo Vivi" <rodrigo.vivi@intel.com>,
        Andi Shyti <andi.shyti@linux.intel.com>,
        Chris Wilson <chris.p.wilson@intel.com>,
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        David Airlie <airlied@linux.ie>,
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        John Harrison <John.C.Harrison@Intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Matthew Brost <matthew.brost@intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 35/37] drm/i915: add descriptions for some RPM macros at intel_gt_pm.h
Date:   Fri,  9 Sep 2022 09:34:42 +0200
Message-Id: <997567dcc2b5942afde093d92d0666948e66d83a.1662708705.git.mchehab@kernel.org>
In-Reply-To: <cover.1662708705.git.mchehab@kernel.org>
References: <cover.1662708705.git.mchehab@kernel.org>
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The intel_gt_pm.h file contains some convenient macros to be used
in GT code in order to get/put runtime PM references and for
checking them.

Add descriptions based on the ones at intel_wakeref.h and
intel_runtime_pm.c.

Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
---

To avoid mailbombing on a large number of people, only mailing lists were C/C on the cover.
See [PATCH v3 00/37] at: https://lore.kernel.org/all/cover.1662708705.git.mchehab@kernel.org/

 Documentation/gpu/i915.rst            |  2 ++
 drivers/gpu/drm/i915/gt/intel_gt_pm.h | 51 +++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst
index 7f5cd01ed398..59c532fe0332 100644
--- a/Documentation/gpu/i915.rst
+++ b/Documentation/gpu/i915.rst
@@ -446,6 +446,8 @@ Graphics Translation Tables
 Other GT functionality
 ----------------------
 
+.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_pm.h
+
 .. kernel-doc:: drivers/gpu/drm/i915/gt/intel_context.h
 
 .. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gsc.h
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
index 6c9a46452364..7847e15d102e 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
@@ -11,21 +11,57 @@
 #include "intel_gt_types.h"
 #include "intel_wakeref.h"
 
+/**
+ * intel_gt_pm_is_awake: Query whether the runtime PM is awake held
+ *
+ * @gt: pointer to the graphics engine
+ *
+ * Returns: true if a runtime pm reference is currently held and the GT is
+ * awake.
+ */
 static inline bool intel_gt_pm_is_awake(const struct intel_gt *gt)
 {
 	return intel_wakeref_is_active(&gt->wakeref);
 }
 
+/**
+ * intel_gt_pm_get: grab a runtime PM reference ensuring that GT is powered up
+ * @gt: pointer to the graphics engine
+ *
+ * Any runtime pm reference obtained by this function must have a symmetric
+ * call to intel_gt_pm_put() to release the reference again.
+ *
+ * Note that this is allowed to fail, in which case the runtime-pm wakeref
+ * will be released and the acquisition unwound.
+ */
 static inline void intel_gt_pm_get(struct intel_gt *gt)
 {
 	intel_wakeref_get(&gt->wakeref);
 }
 
+/**
+ * __intel_gt_pm_get: Acquire the runtime PM reference again
+ * @gt: pointer to the graphics engine which contains the wakeref
+ *
+ * Increment the PM reference counter, only valid if it is already held by
+ * the caller.
+ *
+ * See intel_gt_pm_get().
+ */
 static inline void __intel_gt_pm_get(struct intel_gt *gt)
 {
 	__intel_wakeref_get(&gt->wakeref);
 }
 
+/**
+ * intel_gt_pm_get_if_awake: Acquire the runtime PM reference if active
+ * @gt: pointer to the graphics engine which contains the PM reference
+ *
+ * Acquire a hold on the PM reference, but only if the GT is already
+ * active.
+ *
+ * Returns: true if the wakeref was acquired, false otherwise.
+ */
 static inline bool intel_gt_pm_get_if_awake(struct intel_gt *gt)
 {
 	return intel_wakeref_get_if_active(&gt->wakeref);
@@ -36,6 +72,14 @@ static inline void intel_gt_pm_might_get(struct intel_gt *gt)
 	intel_wakeref_might_get(&gt->wakeref);
 }
 
+/**
+ * intel_gt_pm_put: Release the runtime PM reference
+ * @gt: pointer to the graphics engine which contains the PM reference
+ *
+ * Release our hold on the runtime PM for GT.
+ *
+ * It might power down the GT right away if this is the last reference.
+ */
 static inline void intel_gt_pm_put(struct intel_gt *gt)
 {
 	intel_wakeref_put(&gt->wakeref);
@@ -51,6 +95,13 @@ static inline void intel_gt_pm_might_put(struct intel_gt *gt)
 	intel_wakeref_might_put(&gt->wakeref);
 }
 
+/**
+ * with_intel_gt_pm - get a GT reference ensuring that GT is powered up,
+ *	run some code and then put the reference away.
+ *
+ * @gt: pointer to the gt
+ * @tmp: pointer to a temporary wakeref.
+ */
 #define with_intel_gt_pm(gt, tmp) \
 	for (tmp = 1, intel_gt_pm_get(gt); tmp; \
 	     intel_gt_pm_put(gt), tmp = 0)
-- 
2.37.3