docs(docs): add Obsidian workspace, Android and ARM notes with assets

Add Obsidian notes and assets for Android and ARM Trust Firmware

Added files:
docs/android.md
docs/arm_trust_firmware.md
docs/.gitignore
multiple images under docs/assets/android
and docs/assets/arm_trust_firmware

Removed user-specific Obsidian plugin settings that were tracked:
docs/.obsidian/community-plugins.json
docs/.obsidian/plugins/obsidian-git/data.json

Updated docs/.obsidian/workspace.json to switch the active pane to
android, update the file list, and include Excalidraw plugin entry

Signed-off-by: alanhc <alan.tseng.cs@gmail.com>

Author: alanhc

docs/.gitignore

@@ -0,0 +1,2 @@
+Excalidraw
+.obsidian/

docs/.obsidian/community-plugins.json

@@ -13,15 +13,30 @@
             "state": {
               "type": "markdown",
               "state": {
-                "file": "人際.md",
+                "file": "android.md",
                 "mode": "source",
                 "source": false
               },
               "icon": "lucide-file",
-              "title": "人際"
+              "title": "android"
+            }
+          },
+          {
+            "id": "df74cdc8dec87d80",
+            "type": "leaf",
+            "state": {
+              "type": "markdown",
+              "state": {
+                "file": "android.md",
+                "mode": "source",
+                "source": false
+              },
+              "icon": "lucide-file",
+              "title": "android"
             }
           }
-        ]
+        ],
+        "currentTab": 1
       }
     ],
     "direction": "vertical"
@@ -181,36 +196,43 @@
       "templates:Insert template": false,
       "command-palette:Open command palette": false,
       "bases:Create new base": false,
-      "obsidian-git:Open Git source control": false
+      "obsidian-git:Open Git source control": false,
+      "obsidian-excalidraw-plugin:New drawing": false
     }
   },
-  "active": "e8e61b022fb722ce",
+  "active": "df74cdc8dec87d80",
   "lastOpenFiles": [
+    "android_build_project.md",
+    "arm_trust_firmware.md",
+    "assets/arm_trust_firmware/file-20251206232722738.png",
+    "assets/arm_trust_firmware/file-20251206232655455.png",
+    "assets/arm_trust_firmware/file-20251206232646002.png",
+    "assets/arm_trust_firmware/file-20251206232543489.png",
+    "assets/arm_trust_firmware/file-20251206232407742.png",
+    "assets/arm_trust_firmware/file-20251206232336567.png",
+    "assets/arm_trust_firmware",
+    "android.md",
+    "Excalidraw/Drawing 2025-12-06 23.17.49.excalidraw.md",
+    "Excalidraw",
+    "assets/android/file-20251206231603405.png",
+    "assets/android/file-20251206231507911.png",
+    "assets/android/file-20251206231448138.png",
+    "assets/android",
+    "atf.md",
     "反直覺.md",
-    "投資計劃.md",
-    "酒田戰法.md",
     "投資.md",
     "人際.md",
+    "投資計劃.md",
+    "酒田戰法.md",
     "learning.md",
     "life.md",
     "obsidian.md",
     "mcp.md",
     "health.md",
-    "android_build_project.md",
     "AI.md",
     "assets/obsidian/file-20251206225649111.png",
     "assets/obsidian",
-    "assets/obsidian/file-20251206225633195.png",
-    "assets/obsidian/file-20251206225446317.png",
-    "assets/obsidian/file-20251206225439106.png",
-    "assets/obsidian/file-20251206225250654.png",
     "openwebui.md",
-    "assets/obsidian/file-20251206225226687.png",
-    "assets/obsidian/file-20251206225220004.png",
-    "assets/obsidian/file-20251206225126183.png",
-    "assets/obsidian/file-20251206225145146.png",
-    "assets/obsidian/file-20251206225017624.png",
-    "android.md",
     "簡報.md"
   ]
 }

docs/.obsidian/plugins/obsidian-git/data.json

@@ -1,10 +1,17 @@
+![](assets/android/file-20251206231448138.png)
 
+![](assets/android/file-20251206231603405.png)
+https://developer.android.com/guide/platform?hl=zh-tw
+## kernel
+![](assets/android/file-20251206231507911.png)
 
 
 
 
 - adb
-
+## android booting
 - [Android白话启动篇（Android booting process](https://blog.csdn.net/eliot_shao/article/details/51800310)
 ![alt text](assets/image-android.png)
-A Deep Dive into the Android Boot Process: Step-by-Step Breakdown.https://www.linkedin.com/pulse/deep-dive-android-boot-process-step-by-step-breakdown-santilli-9cdbf/
+A Deep Dive into the Android Boot Process: Step-by-Step Breakdown.https://www.linkedin.com/pulse/deep-dive-android-boot-process-step-by-step-breakdown-santilli-9cdbf/
+
+## linux boot vs android boot

docs/.obsidian/workspace.json

@@ -0,0 +1,32 @@
+
+What: ARM 官方的Secure World 執行環境的詞作
+Why: ARMv8 引入 Trustzone+EL3(Secure Monitor)，並且不再維護vendor BL1 BL2
+When Armv8 2013-14第一版ATF 2015 ATF 成標準
+
+## Major component 
+- Boot loader (BL1 BL2 BL31 BL32 BL33)
+- TF-A
+- PSCI
+- SMC Dispatcher
+- SiPserice
+- Certificated Chain/ROT(Root of Truest)
+
+## 名詞解釋
+- ATF
+- TEE
+- BL Boot Process
+- ARM Exeception Level
+- OP-TEE
+- Secure Boot Chain
+- trustzone
+- secure world
+
+![](assets/arm_trust_firmware/file-20251206232407742.png)
+
+BL1 BL2 BL31 BL32 BL31 BL33 
+
+![](assets/arm_trust_firmware/file-20251206232543489.png)
+https://pyjamabrah.com/posts/arm64-day0-exception-levels/
+![](assets/arm_trust_firmware/file-20251206232646002.png)
+![](assets/arm_trust_firmware/file-20251206232722738.png)
+https://www.cnblogs.com/arnoldlu/p/14175126.html