drm_hwcomposer: Add platform backend for minigbm

This adds support for the chromiumos (not AOSP) version of minigbm. Like
hisi, the gralloc handle is not the same as the common libdrm handle
(just yet), so we do need a separate backend for now.

Tested with a pending change to the 'cuttlefish' android virtual device
in AOSP with its custom gralloc switched to minigbm.

Cc: John Stultz <john.stultz@linaro.org>
Cc: Rob Herring <rob.herring@linaro.org>
Cc: Sean Paul <seanpaul@google.com>
Cc: Greg Hartman <ghartman@google.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Alistair Strachan <astrachan@google.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>

diff --git a/platformminigbm.cpp b/platformminigbm.cpp
new file mode 100644
index 0000000..80e2c0f
--- /dev/null
+++ b/platformminigbm.cpp
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "hwc-platform-drm-minigbm"
+
+#include "drmresources.h"
+#include "platform.h"
+#include "platformminigbm.h"
+
+#include <drm/drm_fourcc.h>
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+#include <log/log.h>
+#include <hardware/gralloc.h>
+
+#include "cros_gralloc_handle.h"
+
+namespace android {
+
+Importer *Importer::CreateInstance(DrmResources *drm) {
+  DrmMinigbmImporter *importer = new DrmMinigbmImporter(drm);
+  if (!importer)
+    return NULL;
+
+  int ret = importer->Init();
+  if (ret) {
+    ALOGE("Failed to initialize the minigbm importer %d", ret);
+    delete importer;
+    return NULL;
+  }
+  return importer;
+}
+
+DrmMinigbmImporter::DrmMinigbmImporter(DrmResources *drm) : DrmGenericImporter(drm), drm_(drm) {
+}
+
+DrmMinigbmImporter::~DrmMinigbmImporter() {
+}
+
+int DrmMinigbmImporter::Init() {
+  int ret = hw_get_module(GRALLOC_HARDWARE_MODULE_ID,
+                          (const hw_module_t **)&gralloc_);
+  if (ret) {
+    ALOGE("Failed to open gralloc module %d", ret);
+    return ret;
+  }
+
+  if (strcasecmp(gralloc_->common.author, "Chrome OS"))
+    ALOGW("Using non-minigbm gralloc module: %s/%s\n", gralloc_->common.name,
+          gralloc_->common.author);
+
+  return 0;
+}
+
+EGLImageKHR DrmMinigbmImporter::ImportImage(EGLDisplay egl_display, buffer_handle_t handle) {
+  cros_gralloc_handle *gr_handle = (cros_gralloc_handle *)handle;
+  if (!gr_handle)
+    return NULL;
+  EGLint attr[] = {
+    EGL_WIDTH, (EGLint)gr_handle->width,
+    EGL_HEIGHT, (EGLint)gr_handle->height,
+    EGL_LINUX_DRM_FOURCC_EXT, (EGLint)gr_handle->format,
+    EGL_DMA_BUF_PLANE0_FD_EXT, gr_handle->fds[0],
+    EGL_DMA_BUF_PLANE0_PITCH_EXT, (EGLint)gr_handle->strides[0],
+    EGL_DMA_BUF_PLANE0_OFFSET_EXT, (EGLint)gr_handle->offsets[0],
+    EGL_NONE,
+  };
+  return eglCreateImageKHR(egl_display, EGL_NO_CONTEXT, EGL_LINUX_DMA_BUF_EXT, NULL, attr);
+}
+
+int DrmMinigbmImporter::ImportBuffer(buffer_handle_t handle, hwc_drm_bo_t *bo) {
+  cros_gralloc_handle *gr_handle = (cros_gralloc_handle *)handle;
+  if (!gr_handle)
+    return -EINVAL;
+
+  uint32_t gem_handle;
+  int ret = drmPrimeFDToHandle(drm_->fd(), gr_handle->fds[0], &gem_handle);
+  if (ret) {
+    ALOGE("failed to import prime fd %d ret=%d", gr_handle->fds[0], ret);
+    return ret;
+  }
+
+  memset(bo, 0, sizeof(hwc_drm_bo_t));
+  bo->width = gr_handle->width;
+  bo->height = gr_handle->height;
+  bo->format = gr_handle->format;
+  bo->usage = gr_handle->usage;
+  bo->pitches[0] = gr_handle->strides[0];
+  bo->offsets[0] = gr_handle->offsets[0];
+  bo->gem_handles[0] = gem_handle;
+
+  ret = drmModeAddFB2(drm_->fd(), bo->width, bo->height, bo->format,
+                      bo->gem_handles, bo->pitches, bo->offsets, &bo->fb_id, 0);
+  if (ret) {
+    ALOGE("could not create drm fb %d", ret);
+    return ret;
+  }
+
+  return ret;
+}
+
+std::unique_ptr<Planner> Planner::CreateInstance(DrmResources *) {
+  std::unique_ptr<Planner> planner(new Planner);
+  planner->AddStage<PlanStageGreedy>();
+  return planner;
+}
+
+}