From dd3e685bf00efbec6ea6533b3a2ad01ccaf89cfb Mon Sep 17 00:00:00 2001
From: Michal Moskal <michal@moskal.me>
Date: Mon, 21 Nov 2016 22:05:39 -0600
Subject: [PATCH] Add user-space program to update bootloader

---
 Makefile                   | 11 +++++++----
 TODO.md                    |  5 ++++-
 inc/uf2.h                  |  3 ++-
 scripts/samd21j18a_self.ld |  2 +-
 src/main.c                 |  9 +++------
 src/selfmain.c             |  8 ++++++++
 src/utils.c                |  7 +++++++
 7 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/Makefile b/Makefile
index 8a60cd89..5a58e682 100644
--- a/Makefile
+++ b/Makefile
@@ -53,7 +53,7 @@ SELF_OBJECTS = $(patsubst src/%.c,$(BUILD_PATH)/%.o,$(SELF_SOURCES)) $(BUILD_PAT
 
 NAME=uf2-bootloader
 EXECUTABLE=$(BUILD_PATH)/$(NAME).bin
-SELF_EXECUTABLE=$(BUILD_PATH)/self-$(NAME).bin
+SELF_EXECUTABLE=$(BUILD_PATH)/self-$(NAME).uf2
 
 all: dirs $(EXECUTABLE) $(SELF_EXECUTABLE) build/uf2conv
 
@@ -73,6 +73,9 @@ wait:
 logs:
 	sh scripts/getlogs.sh $(BUILD_PATH)/$(NAME).map
 
+selflogs:
+	sh scripts/getlogs.sh $(BUILD_PATH)/self-$(NAME).map
+
 dirs:
 	@echo "Building $(BOARD)"
 	-@mkdir -p $(BUILD_PATH)
@@ -86,12 +89,12 @@ $(EXECUTABLE): $(OBJECTS)
 	@node -p '"Free space: " + (8192 - require("fs").readFileSync("$(BUILD_PATH)/$(NAME).bin").length)'
 
 
-$(SELF_EXECUTABLE): $(SELF_OBJECTS) 
+$(SELF_EXECUTABLE): $(SELF_OBJECTS)  build/uf2conv
 	$(CC) -L$(BUILD_PATH) $(LDFLAGS) \
 		 -T./scripts/samd21j18a_self.ld \
 		 -Wl,-Map,$(BUILD_PATH)/self-$(NAME).map -o $(BUILD_PATH)/self-$(NAME).elf $(SELF_OBJECTS)
-	arm-none-eabi-objcopy -O binary $(BUILD_PATH)/self-$(NAME).elf $@
-
+	arm-none-eabi-objcopy -O binary $(BUILD_PATH)/self-$(NAME).elf $(BUILD_PATH)/self-$(NAME).bin
+	./build/uf2conv $(BUILD_PATH)/self-$(NAME).bin $@
 
 $(BUILD_PATH)/%.o: src/%.c $(wildcard inc/*.h)
 	@echo "$<"
diff --git a/TODO.md b/TODO.md
index 1f861706..73354563 100644
--- a/TODO.md
+++ b/TODO.md
@@ -7,7 +7,10 @@
 * [x] organize board configs in directories
 * [x] if `!USE_CDC && !USE_UART` - don't compile monitor
 * [x] if `!USE_CDC` don't compile the CDC code (not only exclude descriptors)
-* [ ] write user program for updating bootloader
+* [x] write user program for updating bootloader
+* [ ] document self-updater
+* [ ] write u2fconv in .js
+* [ ] investigate some blinking
 
 ## Bigger
 * [ ] look into reset into bootloader from host to continue flashing
diff --git a/inc/uf2.h b/inc/uf2.h
index 133f6953..5fc20f11 100644
--- a/inc/uf2.h
+++ b/inc/uf2.h
@@ -21,7 +21,7 @@
 #define INDEX_URL "https://www.pxt.io/"
 #endif
 
-#define UF2_VERSION "v1.0.0"
+#define UF2_VERSION "v1.0.5"
 
 // needs to be more than ~4200 (to force FAT16)
 #define NUM_FAT_BLOCKS 8000
@@ -123,6 +123,7 @@ inline void bulb_off(void) { PORT->Group[BULB_PORT].OUTCLR.reg = (1 << BULB_PIN)
 
 extern uint32_t timerHigh, resetHorizon, blinkHorizon;
 void timerTick(void);
+void delay(uint32_t ms);
 
 #define CONCAT_1(a, b) a ## b
 #define CONCAT_0(a, b) CONCAT_1(a, b)
diff --git a/scripts/samd21j18a_self.ld b/scripts/samd21j18a_self.ld
index 782ca5c5..4c3e9ef9 100644
--- a/scripts/samd21j18a_self.ld
+++ b/scripts/samd21j18a_self.ld
@@ -49,7 +49,7 @@ SEARCH_DIR(.)
 /* Memory Spaces Definitions */
 MEMORY
 {
-  rom      (rx)  : ORIGIN = 0x00000000, LENGTH = 0x00020000
+  rom      (rx)  : ORIGIN = 0x00002000, LENGTH = 0x00020000
   ram      (rwx) : ORIGIN = 0x20000000, LENGTH = 0x00008000
 }
 
diff --git a/src/main.c b/src/main.c
index 69d68fce..d28fddee 100644
--- a/src/main.c
+++ b/src/main.c
@@ -92,10 +92,9 @@ static void check_start_application(void) {
 
     /**
      * Test reset vector of application @APP_START_ADDRESS+4
-     * Stay in SAM-BA if *(APP_START+0x4) == 0xFFFFFFFF
-     * Application erased condition
+     * Sanity check on the Reset_Handler address
      */
-    if (app_start_address == 0xFFFFFFFF) {
+    if (app_start_address < APP_START_ADDRESS || app_start_address > FLASH_SIZE) {
         /* Stay in bootloader */
         return;
     }
@@ -108,9 +107,7 @@ static void check_start_application(void) {
     } else {
         if (*DBL_TAP_PTR != DBL_TAP_MAGIC_QUICK_BOOT) {
             *DBL_TAP_PTR = DBL_TAP_MAGIC;
-            for (int i = 1; i < 100000; ++i) {
-                asm("nop");
-            }
+            delay(500);
         }
         *DBL_TAP_PTR = 0;
     }
diff --git a/src/selfmain.c b/src/selfmain.c
index 6c41b7ae..f2f0faba 100644
--- a/src/selfmain.c
+++ b/src/selfmain.c
@@ -44,6 +44,14 @@ int main(void) {
 
     logmsg("Update successful!");
 
+    // erase first row of this updater app, so the bootloader doesn't start us again
+    flash_erase_row((void*)i);
+
+    for (i = 0; i < 20; ++i) {
+        bulb_toggle();
+        delay(200);
+    }
+
     bulb_off();
 
     resetIntoBootloader();
diff --git a/src/utils.c b/src/utils.c
index eac1654f..4e3ac2b0 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -3,6 +3,13 @@
 static uint32_t timerLow;
 uint32_t timerHigh, resetHorizon, blinkHorizon;
 
+void delay(uint32_t ms) {
+    ms <<= 8;
+    for (int i = 1; i < ms; ++i) {
+        asm("nop");
+    }
+}
+
 void timerTick(void) {
     if (timerLow-- == 0) {
         timerLow = TIMER_STEP;