[PATCH v2 1/4] drm: Adding new flag to restrict bitmask drm properties as 32 bit type and 32 bit value pair

[sagar . a . kamble]

From: Sagar Kamble <sagar.a.kamble@xxxxxxxxx>

With this patch new flag DRM_MODE_PROP_32BIT_PAIR is added that will help make use
of 64 bit value of bitmask property as two 32 bit values.

Cc: airlied@xxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Sagar Kamble <sagar.a.kamble@xxxxxxxxx>
---
 drivers/gpu/drm/drm_crtc.c  | 22 ++++++++++++++++------
 include/uapi/drm/drm_mode.h |  3 +++
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 4e43fc2..d0d03ec 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2993,10 +2993,13 @@ int drm_property_add_enum(struct drm_property *property, int index,
 
 	/*
 	 * Bitmask enum properties have the additional constraint of values
-	 * from 0 to 63
+	 * from 0 to 63. For properties with 32BIT_PAIR Flag set this constraint
+	 * range is 0 to 31.
 	 */
-	if ((property->flags & DRM_MODE_PROP_BITMASK) && (value > 63))
-		return -EINVAL;
+	if (property->flags & DRM_MODE_PROP_BITMASK)
+		if (((property->flags & DRM_MODE_PROP_32BIT_PAIR) && (value > 31)) ||
+		    (value > 63))
+			return -EINVAL;
 
 	if (!list_empty(&property->enum_blob_list)) {
 		list_for_each_entry(prop_enum, &property->enum_blob_list, head) {
@@ -3305,9 +3308,16 @@ static bool drm_property_change_is_valid(struct drm_property *property,
 	} else if (property->flags & DRM_MODE_PROP_BITMASK) {
 		int i;
 		uint64_t valid_mask = 0;
-		for (i = 0; i < property->num_values; i++)
-			valid_mask |= (1ULL << property->values[i]);
-		return !(value & ~valid_mask);
+		uint32_t valid_32bit_mask = 0;
+		if (property->flags & DRM_MODE_PROP_32BIT_PAIR) {
+			for (i = 0; i < property->num_values; i++)
+				valid_32bit_mask |= (1UL << property->values[i]);
+			return !((value & 0xFFFFFFFF) & ~valid_32bit_mask);
+		} else {
+			for (i = 0; i < property->num_values; i++)
+				valid_mask |= (1ULL << property->values[i]);
+			return !(value & ~valid_mask);
+		}
 	} else if (property->flags & DRM_MODE_PROP_BLOB) {
 		/* Only the driver knows */
 		return true;
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index f104c26..5e3a7d9 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -250,6 +250,9 @@ struct drm_mode_get_connector {
 #define DRM_MODE_PROP_ENUM	(1<<3) /* enumerated type with text strings */
 #define DRM_MODE_PROP_BLOB	(1<<4)
 #define DRM_MODE_PROP_BITMASK	(1<<5) /* bitmask of enumerated types */
+#define DRM_MODE_PROP_32BIT_PAIR (1<<6) /* 32 bit bitmask of enumerated types
+					 * and 32 bit of value of the type */
+
 
 struct drm_mode_property_enum {
 	__u64 value;
-- 
1.8.5

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