[S] Change in coreboot[main]: util/mediatek: Add check-pi-img.py

[Yu-Ping Wu (Code Review)]

Yu-Ping Wu has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/87226?usp=email )

Change subject: util/mediatek: Add check-pi-img.py
......................................................................

util/mediatek: Add check-pi-img.py

Add a script to perform validity check of the PI_IMG firmware.

Change-Id: I27011492c7fab747aa3ee12d514d20a6a52d0a4d
Signed-off-by: Yu-Ping Wu 
---
M Documentation/util.md
M util/README.md
A util/mediatek/check-pi-img.py
M util/mediatek/description.md
4 files changed, 38 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/26/87226/1

diff --git a/Documentation/util.md b/Documentation/util.md
index 8a52557..6ac904a 100644
--- a/Documentation/util.md
+++ b/Documentation/util.md
@@ -88,6 +88,7 @@
 * __[me_cleaner](https://github.com/corna/me_cleaner)__ - Tool for
 partial deblobbing of Intel ME/TXE firmware images `Python`
 * __mediatek__
+	* check-pi-img.py - Check `PI_IMG` firmware. `Python3`
    * gen-bl-img.py - Generate MediaTek bootloader header.
 `Python3`
 * __mma__ - Memory Margin Analysis automation tests `Bash`
diff --git a/util/README.md b/util/README.md
index 0253a71..099845d 100644
--- a/util/README.md
+++ b/util/README.md
@@ -79,6 +79,7 @@
 * __[me_cleaner](https://github.com/corna/me_cleaner)__ - Tool for
 partial deblobbing of Intel ME/TXE firmware images `Python`
 * __mediatek__
+	* check-pi-img.py - Check `PI_IMG` firmware. `Python3`
    * gen-bl-img.py - Generate MediaTek bootloader header.
 `Python3`
 * __mma__ - Memory Margin Analysis automation tests `Bash`
diff --git a/util/mediatek/check-pi-img.py b/util/mediatek/check-pi-img.py
new file mode 100755
index 0000000..1587dbe
--- /dev/null
+++ b/util/mediatek/check-pi-img.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+#
+# SPDX-License-Identifier: GPL-2.0-only
+
+import argparse
+
+
+HEADER_OFFSET = 0x200
+COOKIE = 0x17C3A6B4
+
+
+def check_pi_img(pi_img):
+    cookie_count = 0
+    with open(pi_img, "rb") as f:
+        f.seek(HEADER_OFFSET)
+        while True:
+            data = f.read(4)
+            if not data:
+                break
+            value = int.from_bytes(data, byteorder="little", signed=False)
+            if value == COOKIE:
+                cookie_count += 1
+    if cookie_count != 2:
+        raise ValueError("Invalid PI_IMG {}, {} cookies found"
+                         .format(pi_img, cookie_count))
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("pi_img")
+    args = parser.parse_args()
+    check_pi_img(args.pi_img)
+
+if __name__ == '__main__':
+    main()
diff --git a/util/mediatek/description.md b/util/mediatek/description.md
index 67ff390..568c8bb 100644
--- a/util/mediatek/description.md
+++ b/util/mediatek/description.md
@@ -1,2 +1,3 @@
 __mediatek__
+  * check-pi-img.py - Check `PI_IMG` firmware. `Python3`
   * gen-bl-img.py - Generate MediaTek bootloader header. `Python3`