hwc3: edid: move EDID parsing to a separate file

Bug: b/328091332
Test: presubmit
Change-Id: I922fcb5cc70ebfda44fdf70632f4868a8ff25198

5 files changed, 61 insertions, 25 deletions

diff --git a/system/hwc3/Android.bp b/system/hwc3/Android.bp
index ccbab191..a08a1bed 100644
--- a/system/hwc3/Android.bp
+++ b/system/hwc3/Android.bp
@@ -77,6 +77,7 @@ cc_binary {
         "DrmEventListener.cpp",
         "DrmMode.cpp",
         "DrmPlane.cpp",
+        "EdidInfo.cpp",
         "Gralloc.cpp",
         "GuestFrameComposer.cpp",
         "HostFrameComposer.cpp",
diff --git a/system/hwc3/DrmConnector.cpp b/system/hwc3/DrmConnector.cpp
index dac64058..c5f9e0d8 100644
--- a/system/hwc3/DrmConnector.cpp
+++ b/system/hwc3/DrmConnector.cpp
@@ -18,6 +18,8 @@
 
 #include <span>
 
+#include "EdidInfo.h"
+
 namespace aidl::android::hardware::graphics::composer3::impl {
 namespace {
 
@@ -67,9 +69,14 @@ bool DrmConnector::update(::android::base::borrowed_fd drmFd) {
     drmModeFreeConnector(drmConnector);
 
     if (mStatus == DRM_MODE_CONNECTED) {
-        if (!loadEdid(drmFd)) {
+        std::optional<EdidInfo> maybeEdidInfo = loadEdid(drmFd);
+        if (!maybeEdidInfo) {
+            ALOGE("%s: failed to parse EDID info for display:%" PRIu32 ".", __FUNCTION__, mId);
             return false;
         }
+        const EdidInfo& edidInfo = maybeEdidInfo.value();
+        mWidthMillimeters = edidInfo.mWidthMillimeters;
+        mHeightMillimeters = edidInfo.mHeightMillimeters;
     }
 
     DEBUG_LOG("%s: connector:%" PRIu32 " widthMillimeters:%" PRIu32 " heightMillimeters:%" PRIu32,
@@ -79,20 +86,20 @@ bool DrmConnector::update(::android::base::borrowed_fd drmFd) {
     return true;
 }
 
-bool DrmConnector::loadEdid(::android::base::borrowed_fd drmFd) {
+std::optional<EdidInfo> DrmConnector::loadEdid(::android::base::borrowed_fd drmFd) {
     DEBUG_LOG("%s: display:%" PRIu32, __FUNCTION__, mId);
 
     const uint64_t edidBlobId = mEdidProp.getValue();
     if (edidBlobId == -1) {
         ALOGW("%s: display:%" PRIu32 " does not have EDID.", __FUNCTION__, mId);
-        return true;
+        return std::nullopt;
     }
 
     auto blob = drmModeGetPropertyBlob(drmFd.get(), static_cast<uint32_t>(edidBlobId));
     if (!blob) {
         ALOGE("%s: display:%" PRIu32 " failed to read EDID blob (%" PRIu64 "): %s", __FUNCTION__,
               mId, edidBlobId, strerror(errno));
-        return false;
+        return std::nullopt;
     }
 
     const uint8_t* blobStart = static_cast<uint8_t*>(blob->data);
@@ -101,28 +108,9 @@ bool DrmConnector::loadEdid(::android::base::borrowed_fd drmFd) {
     drmModeFreePropertyBlob(blob);
 
     using byte_view = std::span<const uint8_t>;
-
-    constexpr size_t kEdidDescriptorOffset = 54;
-    constexpr size_t kEdidDescriptorLength = 18;
-
     byte_view edid(*mEdid);
-    edid = edid.subspan(kEdidDescriptorOffset);
 
-    byte_view descriptor(edid.data(), kEdidDescriptorLength);
-    if (descriptor[0] == 0 && descriptor[1] == 0) {
-        ALOGE("%s: display:%" PRIu32 " is missing preferred detailed timing descriptor.",
-              __FUNCTION__, mId);
-        return -1;
-    }
-
-    const uint8_t w_mm_lsb = descriptor[12];
-    const uint8_t h_mm_lsb = descriptor[13];
-    const uint8_t w_and_h_mm_msb = descriptor[14];
-
-    mWidthMillimeters = w_mm_lsb | (w_and_h_mm_msb & 0xf0) << 4;
-    mHeightMillimeters = h_mm_lsb | (w_and_h_mm_msb & 0xf) << 8;
-
-    return true;
+    return EdidInfo::parse(edid);
 }
 
 uint32_t DrmConnector::getWidth() const {
diff --git a/system/hwc3/DrmConnector.h b/system/hwc3/DrmConnector.h
index 1cc46c5c..f908631d 100644
--- a/system/hwc3/DrmConnector.h
+++ b/system/hwc3/DrmConnector.h
@@ -30,6 +30,7 @@
 #include "Common.h"
 #include "DrmMode.h"
 #include "DrmProperty.h"
+#include "EdidInfo.h"
 
 namespace aidl::android::hardware::graphics::composer3::impl {
 
@@ -63,7 +64,7 @@ class DrmConnector {
    private:
     DrmConnector(uint32_t id) : mId(id) {}
 
-    bool loadEdid(::android::base::borrowed_fd drmFd);
+    std::optional<EdidInfo> loadEdid(::android::base::borrowed_fd drmFd);
 
     const uint32_t mId;
 
diff --git a/system/hwc3/EdidInfo.cpp b/system/hwc3/EdidInfo.cpp
new file mode 100644
index 00000000..e4b63fa6
--- /dev/null
+++ b/system/hwc3/EdidInfo.cpp
@@ -0,0 +1,30 @@
+#include "EdidInfo.h"
+
+#include "Common.h"
+
+namespace aidl::android::hardware::graphics::composer3::impl {
+std::optional<EdidInfo> EdidInfo::parse(std::span<const uint8_t> blob) {
+    constexpr size_t kEdidDescriptorOffset = 54;
+    constexpr size_t kEdidDescriptorLength = 18;
+
+    blob = blob.subspan(kEdidDescriptorOffset);
+
+    using byte_view = std::span<const uint8_t>;
+    byte_view descriptor(blob.data(), kEdidDescriptorLength);
+    if (descriptor[0] == 0 && descriptor[1] == 0) {
+        ALOGE("%s: missing preferred detailed timing descriptor", __FUNCTION__);
+        return std::nullopt;
+    }
+
+    const uint8_t w_mm_lsb = descriptor[12];
+    const uint8_t h_mm_lsb = descriptor[13];
+    const uint8_t w_and_h_mm_msb = descriptor[14];
+
+    return EdidInfo{
+        .mWidthMillimeters =
+            static_cast<uint32_t>(w_mm_lsb) | ((static_cast<uint32_t>(w_and_h_mm_msb) & 0xf0) << 4),
+        .mHeightMillimeters =
+            static_cast<uint32_t>(h_mm_lsb) | ((static_cast<uint32_t>(w_and_h_mm_msb) & 0xf) << 8),
+    };
+}
+}  // namespace aidl::android::hardware::graphics::composer3::impl
diff --git a/system/hwc3/EdidInfo.h b/system/hwc3/EdidInfo.h
new file mode 100644
index 00000000..bcccebfd
--- /dev/null
+++ b/system/hwc3/EdidInfo.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include <cinttypes>
+#include <optional>
+#include <span>
+
+namespace aidl::android::hardware::graphics::composer3::impl {
+
+struct EdidInfo {
+    uint32_t mWidthMillimeters = 0;
+    uint32_t mHeightMillimeters = 0;
+
+    static std::optional<EdidInfo> parse(std::span<const uint8_t> blob);
+};
+
+}  // namespace aidl::android::hardware::graphics::composer3::impl