linux-kernel - [PATCH v2] drm: add ARM interleaved 64k modifier

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Message-ID: <20260127110740.473562-1-caterina.shablia@collabora.com>
Date: Tue, 27 Jan 2026 11:07:39 +0000
From: Caterina Shablia <caterina.shablia@...labora.com>
To: David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>
Cc: kernel@...labora.com,
	Caterina Shablia <caterina.shablia@...labora.com>,
	"Boris Brezillon" <boris.brezillon@...labora.com>,
	"Steven Price" <steven.price@....com>,
	"Liviu Dudau" <liviu.dudau@....com>,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] drm: add ARM interleaved 64k modifier

This modifier is primarily intended to be used by panvk to implement
sparse partially-resident images with better map and unmap
performance, and no worse access performance, compared to
implementing them in terms of U-interleaved.

With this modifier, the plane is divided into 64k byte 1:1 or 2:1
-sided tiles. The 64k tiles are laid out linearly. Each 64k tile
is divided into blocks of 16x16 texel blocks each, which themselves
are laid out linearly within a 64k tile. Then within each such
16x16 block, texel blocks are laid out according to U order,
similar to 16X16_BLOCK_U_INTERLEAVED.

Unlike 16X16_BLOCK_U_INTERLEAVED, the layout does not depend on
whether a format is compressed or not.

The hardware features corresponding to this modifier are available
starting with v10 (second gen Valhall.)

The corresponding panvk MR can be found at:
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38986

Previous patch:
https://lists.freedesktop.org/archives/dri-devel/2026-January/546655.html

Changes since v1:

* Rewrite the description of the modifier to be hopefully unambiguous.

Signed-off-by: Caterina Shablia <caterina.shablia@...labora.com>
---
 include/uapi/drm/drm_fourcc.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index e527b24bd824..452f901513ad 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -1422,6 +1422,22 @@ drm_fourcc_canonicalize_nvidia_format_mod(__u64 modifier)
 #define DRM_FORMAT_MOD_ARM_16X16_BLOCK_U_INTERLEAVED \
 	DRM_FORMAT_MOD_ARM_CODE(DRM_FORMAT_MOD_ARM_TYPE_MISC, 1ULL)
 
+/*
+ * ARM 64k interleaved modifier
+ *
+ * This is used by ARM Mali v10+ GPUs. With this modifier, the plane is divided
+ * into 64k byte 1:1 or 2:1 -sided tiles. The 64k tiles are laid out linearly.
+ * Each 64k tile is divided into blocks of 16x16 texel blocks, which are
+ * themselves laid out linearly within a 64k tile. Then within each 16x16
+ * block, texel blocks are laid out according to U order, similar to
+ * 16X16_BLOCK_U_INTERLEAVED.
+ *
+ * Note that unlike 16X16_BLOCK_U_INTERLEAVED, the layout does not change
+ * depending on whether a format is compressed or not.
+ */
+#define DRM_FORMAT_MOD_ARM_INTERLEAVED_64K \
+	DRM_FORMAT_MOD_ARM_CODE(DRM_FORMAT_MOD_ARM_TYPE_MISC, 2ULL)
+
 /*
  * Allwinner tiled modifier
  *

base-commit: f08f665f8cda9520d98ee24545d306a92f386616
-- 
2.47.3