From bd0c7de2bf8b0d4de397c31bb390b184c33a45e8 Mon Sep 17 00:00:00 2001
From: Gabriel Ozouf <gabriel.ozouf@numworks.com>
Date: Wed, 31 Mar 2021 13:19:46 +0200
Subject: [PATCH] [ion] Create method to lock PCB versions on old boards

---
 apps/on_boarding/power_on_self_test.cpp |  5 +++++
 ion/include/ion.h                       |  1 +
 ion/include/ion/board.h                 | 12 ++++++++++++
 ion/src/device/n0100/drivers/board.cpp  |  2 ++
 ion/src/device/n0110/drivers/board.cpp  |  7 ++++++-
 ion/src/device/shared/drivers/board.cpp | 23 +++++++++++++++++++++++
 ion/src/device/shared/drivers/board.h   |  6 ++++++
 ion/src/shared/dummy/board.cpp          |  4 ++++
 ion/src/simulator/Makefile              |  1 +
 9 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 ion/include/ion/board.h
 create mode 100644 ion/src/shared/dummy/board.cpp

diff --git a/apps/on_boarding/power_on_self_test.cpp b/apps/on_boarding/power_on_self_test.cpp
index 5bdeb1807..85d4378cd 100644
--- a/apps/on_boarding/power_on_self_test.cpp
+++ b/apps/on_boarding/power_on_self_test.cpp
@@ -1,5 +1,6 @@
 #include "power_on_self_test.h"
 #include <apps/shared/post_and_hardware_tests.h>
+#include <ion/board.h>
 #include <ion/led.h>
 
 namespace OnBoarding {
@@ -8,6 +9,10 @@ KDColor PowerOnSelfTest::Perform() {
   KDColor previousLEDColor = Ion::LED::getColor();
   KDColor resultColor = KDColorWhite;
 
+  /* Lock OTP on older devices to prevent garbage being written where the PCB
+   * version is read. */
+  Ion::Board::lockUnlockedPCBVersion();
+
   // Screen tests
   bool screenTestsOK = Shared::POSTAndHardwareTests::VBlankOK() && (Shared::POSTAndHardwareTests::TextLCDGlyphFailures() <= k_textErrorsLimit);
   // We push a white screen so that the LCD Data test is invisible for the user.
diff --git a/ion/include/ion.h b/ion/include/ion.h
index e23ba8268..3eeb87745 100644
--- a/ion/include/ion.h
+++ b/ion/include/ion.h
@@ -3,6 +3,7 @@
 
 #include <ion/backlight.h>
 #include <ion/battery.h>
+#include <ion/board.h>
 #include <ion/clipboard.h>
 #include <ion/console.h>
 #include <ion/display.h>
diff --git a/ion/include/ion/board.h b/ion/include/ion/board.h
new file mode 100644
index 000000000..6c7f09a42
--- /dev/null
+++ b/ion/include/ion/board.h
@@ -0,0 +1,12 @@
+#ifndef ION_BOARD_H
+#define ION_BOARD_H
+
+namespace Ion {
+namespace Board {
+
+void lockUnlockedPCBVersion();
+
+}
+}
+
+#endif
diff --git a/ion/src/device/n0100/drivers/board.cpp b/ion/src/device/n0100/drivers/board.cpp
index 5dfe99e0d..cc62fff89 100644
--- a/ion/src/device/n0100/drivers/board.cpp
+++ b/ion/src/device/n0100/drivers/board.cpp
@@ -242,6 +242,8 @@ void writePCBVersion(PCBVersion) {}
 
 void lockPCBVersion() {}
 
+bool pcbVersionIsLocked() { return true; }
+
 }
 }
 }
diff --git a/ion/src/device/n0110/drivers/board.cpp b/ion/src/device/n0110/drivers/board.cpp
index f2a1db2a2..3c11fc5b6 100644
--- a/ion/src/device/n0110/drivers/board.cpp
+++ b/ion/src/device/n0110/drivers/board.cpp
@@ -385,7 +385,8 @@ PCBVersion pcbVersion() {
    * way, flashing the PCB version can be done last. */
   return PCB_LATEST;
 #else
-  return readPCBVersionInMemory();
+  PCBVersion version = readPCBVersionInMemory();
+  return (version == alternateBlankVersion ? 0 : version);
 #endif
 }
 
@@ -405,6 +406,10 @@ void lockPCBVersion() {
   InternalFlash::WriteMemory(destination, &zero, sizeof(zero));
 }
 
+bool pcbVersionIsLocked() {
+  return *reinterpret_cast<const uint8_t *>(InternalFlash::Config::OTPLocksAddress + pcbVersionOTPIndex) == 0;
+}
+
 }
 }
 }
diff --git a/ion/src/device/shared/drivers/board.cpp b/ion/src/device/shared/drivers/board.cpp
index 2407ec993..d0bab734a 100644
--- a/ion/src/device/shared/drivers/board.cpp
+++ b/ion/src/device/shared/drivers/board.cpp
@@ -93,3 +93,26 @@ void setClockFrequency(Frequency f) {
 }
 }
 }
+
+namespace Ion {
+namespace Board {
+
+using namespace Device::Board;
+
+void lockUnlockedPCBVersion() {
+  if (pcbVersionIsLocked()) {
+    return;
+  }
+  /* PCB version is unlocked : the device is a N0110 that has been
+   * produced prior to the pcb revision. */
+  PCBVersion version = pcbVersion();
+  if (version != 0) {
+    /* Some garbage has been written in OTP0. We overwrite it fully, which is
+     * interepreted as blank. */
+    writePCBVersion(alternateBlankVersion);
+  }
+  lockPCBVersion();
+}
+
+}
+}
diff --git a/ion/src/device/shared/drivers/board.h b/ion/src/device/shared/drivers/board.h
index a94d8cd4f..8cf626a16 100644
--- a/ion/src/device/shared/drivers/board.h
+++ b/ion/src/device/shared/drivers/board.h
@@ -26,11 +26,17 @@ void setStandardFrequency(Frequency f);
 void setClockFrequency(Frequency f);
 
 typedef uint32_t PCBVersion;
+/* On N0110 released before the PCB revision, OTP0 is supposed to be blank and
+ * unlocked. However, such a device with something written in OTP0 will be
+ * unable to configure Vbus properly. In this case, and if OTP0 is still
+ * unlocked, we fully write OTP0 and treat it the same as fully blank. */
+constexpr PCBVersion alternateBlankVersion = -1;
 
 PCBVersion pcbVersion();
 PCBVersion readPCBVersionInMemory();
 void writePCBVersion(PCBVersion version);
 void lockPCBVersion();
+bool pcbVersionIsLocked();
 
 }
 }
diff --git a/ion/src/shared/dummy/board.cpp b/ion/src/shared/dummy/board.cpp
new file mode 100644
index 000000000..ad38e793a
--- /dev/null
+++ b/ion/src/shared/dummy/board.cpp
@@ -0,0 +1,4 @@
+#include <ion/board.h>
+
+void Ion::Board::lockUnlockedPCBVersion() {
+}
diff --git a/ion/src/simulator/Makefile b/ion/src/simulator/Makefile
index 862742bd7..61c90073b 100644
--- a/ion/src/simulator/Makefile
+++ b/ion/src/simulator/Makefile
@@ -1,5 +1,6 @@
 ion_src += $(addprefix ion/src/shared/dummy/, \
   backlight.cpp \
+  board.cpp \
   battery.cpp \
   display.cpp \
   exam_mode.cpp \