[PATCH] [RFC] drm_hwcomposer: Add support for Arm Framebuffer Compression (AFBC) modifiers.

[Ayan Halder]

One needs to translate the Gralloc buffer flags for AFBC (eg
MALI_GRALLOC_INTFMT_AFBC_BASIC) to the corresponding linux kernel drm modifiers.
This gets passed to libdrm via drmModeAddFB2WithModifiers.

Signed-off-by: Ayan Kumar Halder <ayan.halder at arm.com>

/-- Note for reviewer
I was able to get this working for Android P on Juno with Mali DP650 and Mali
T860 gpu(with some additional hacks). I have not yet validated this hikey960.

I have used the following components:-
1. Gralloc (from https://android.googlesource.com/device/linaro/hikey/+/master/gralloc960)
  - Built with MALI_MMSS=1
2. Libdrm (from git://anongit.freedesktop.org/mesa/drm)
  - You would need drm_fourcc.h and gralloc_handle.h
--/
---
 platformdrmgeneric.cpp | 42 ++++++++++++++++++++++++++++++++++++++++++
 platformdrmgeneric.h   |  2 ++
 platformhisi.cpp       | 14 ++++++++++++--
 3 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/platformdrmgeneric.cpp b/platformdrmgeneric.cpp
index 503c04a..a520224 100644
--- a/platformdrmgeneric.cpp
+++ b/platformdrmgeneric.cpp
@@ -18,6 +18,7 @@
 
 #include "platformdrmgeneric.h"
 #include "drmdevice.h"
+#include "mali_gralloc_formats.h"
 #include "platform.h"
 
 #include <drm/drm_fourcc.h>
@@ -83,6 +84,31 @@ uint32_t DrmGenericImporter::ConvertHalFormatToDrm(uint32_t hal_format) {
   }
 }
 
+uint64_t DrmGenericImporter::ConvertGrallocFormatToDrmModifiers(uint64_t flags,
+                                                                bool is_rgb) {
+  uint64_t features = 0;
+
+  if (flags & MALI_GRALLOC_INTFMT_AFBC_BASIC)
+    features |= AFBC_FORMAT_MOD_BLOCK_SIZE_16x16;
+
+  if (is_rgb)
+    features |= AFBC_FORMAT_MOD_YTR;
+
+  if (flags & MALI_GRALLOC_INTFMT_AFBC_SPLITBLK)
+    features |= (AFBC_FORMAT_MOD_SPLIT | AFBC_FORMAT_MOD_SPARSE);
+
+  if (flags & MALI_GRALLOC_INTFMT_AFBC_WIDEBLK)
+    features |= AFBC_FORMAT_MOD_BLOCK_SIZE_32x8;
+
+  if (flags & MALI_GRALLOC_INTFMT_AFBC_TILED_HEADERS)
+    features |= AFBC_FORMAT_MOD_TILED;
+
+  if (features)
+    return DRM_FORMAT_MOD_ARM_AFBC(features);
+  else
+    return 0;
+}
+
 uint32_t DrmGenericImporter::DrmFormatToBitsPerPixel(uint32_t drm_format) {
   switch (drm_format) {
     case DRM_FORMAT_ARGB8888:
@@ -101,6 +127,22 @@ uint32_t DrmGenericImporter::DrmFormatToBitsPerPixel(uint32_t drm_format) {
   }
 }
 
+bool DrmGenericImporter::IsDrmFormatRgb(uint32_t drm_format) {
+  switch (drm_format) {
+    case DRM_FORMAT_ARGB8888:
+    case DRM_FORMAT_XBGR8888:
+    case DRM_FORMAT_ABGR8888:
+    case DRM_FORMAT_BGR888:
+    case DRM_FORMAT_BGR565:
+      return true;
+    case DRM_FORMAT_YVU420:
+      return false;
+    default:
+      ALOGE("Unsupported format %u assuming rgb?", drm_format);
+      return true;
+  }
+}
+
 int DrmGenericImporter::ImportBuffer(buffer_handle_t handle, hwc_drm_bo_t *bo) {
   gralloc_handle_t *gr_handle = gralloc_handle(handle);
   if (!gr_handle)
diff --git a/platformdrmgeneric.h b/platformdrmgeneric.h
index 233ba55..43cb618 100644
--- a/platformdrmgeneric.h
+++ b/platformdrmgeneric.h
@@ -36,6 +36,8 @@ class DrmGenericImporter : public Importer {
   bool CanImportBuffer(buffer_handle_t handle) override;
 
   uint32_t ConvertHalFormatToDrm(uint32_t hal_format);
+  uint64_t ConvertGrallocFormatToDrmModifiers(uint64_t flags, bool is_rgb);
+  bool IsDrmFormatRgb(uint32_t drm_format);
   uint32_t DrmFormatToBitsPerPixel(uint32_t drm_format);
 
  private:
diff --git a/platformhisi.cpp b/platformhisi.cpp
index 76fe1e7..1cb7e2c 100644
--- a/platformhisi.cpp
+++ b/platformhisi.cpp
@@ -71,6 +71,9 @@ int HisiImporter::Init() {
 }
 
 int HisiImporter::ImportBuffer(buffer_handle_t handle, hwc_drm_bo_t *bo) {
+  bool is_rgb;
+  uint64_t modifiers[4] = {0};
+
   memset(bo, 0, sizeof(hwc_drm_bo_t));
 
   private_handle_t const *hnd = reinterpret_cast<private_handle_t const *>(
@@ -94,6 +97,10 @@ int HisiImporter::ImportBuffer(buffer_handle_t handle, hwc_drm_bo_t *bo) {
   if (fmt < 0)
     return fmt;
 
+  is_rgb = IsDrmFormatRgb(fmt);
+  modifiers[0] = ConvertGrallocFormatToDrmModifiers(hnd->internal_format,
+                                                    is_rgb);
+
   bo->width = hnd->width;
   bo->height = hnd->height;
   bo->hal_format = hnd->req_format;
@@ -129,8 +136,11 @@ int HisiImporter::ImportBuffer(buffer_handle_t handle, hwc_drm_bo_t *bo) {
       break;
   }
 
-  ret = drmModeAddFB2(drm_->fd(), bo->width, bo->height, bo->format,
-                      bo->gem_handles, bo->pitches, bo->offsets, &bo->fb_id, 0);
+  ret = drmModeAddFB2WithModifiers(drm_->fd(), bo->width, bo->height,
+                                   bo->format, bo->gem_handles, bo->pitches,
+                                   bo->offsets, modifiers, &bo->fb_id,
+                                   modifiers[0] ? DRM_MODE_FB_MODIFIERS : 0);
+
   if (ret) {
     ALOGE("could not create drm fb %d", ret);
     return ret;
-- 
2.7.4