put persistent config storage at end of flash

CMakeLists.txt

@@ -87,6 +87,7 @@ target_sources(gadget PUBLIC
     src/state_volcano_run.c
     src/crafty.c
     src/state_crafty.c
+    src/mem.c
 
     ${CMAKE_CURRENT_BINARY_DIR}/fatfs/ff.c
     ${CMAKE_CURRENT_BINARY_DIR}/fatfs/ffunicode.c
@@ -147,6 +148,8 @@ target_link_libraries(gadget
     pico_btstack_ble
     pico_btstack_cyw43
     pico_cyw43_arch_threadsafe_background
+    hardware_flash
+    pico_flash
 )
 
 target_compile_definitions(gadget PUBLIC

include/mem.h

@@ -0,0 +1,40 @@
+/*
+ * mem.h
+ *
+ * Copyright (c) 2023 Thomas Buck (thomas@xythobuz.de)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * See <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __MEM_H__
+#define __MEM_H__
+
+#include <stdint.h>
+
+#define MEM_VERSION 0x01
+
+struct mem_data {
+    uint8_t version;
+    uint16_t backlight;
+} __attribute__((packed));
+
+#define MEM_DATA_INIT {         \
+    .version = MEM_VERSION,     \
+    .backlight = (0xFF00 >> 1), \
+}
+
+void mem_init(void);
+void mem_write(void);
+struct mem_data *mem_data(void);
+
+#endif // __MEM_H__

src/main.c

@@ -33,6 +33,7 @@
 #include "lcd.h"
 #include "text.h"
 #include "image.h"
+#include "mem.h"
 #include "state.h"
 #include "serial.h"
 #include "workflow.h"
@@ -50,10 +51,13 @@ int main(void) {
     serial_init();
     usb_init();
 
+    debug("mem_init");
+    mem_init();
+
     debug("lcd_init");
     lcd_init();
     draw_splash();
-    lcd_set_backlight(0xFF00 >> 1);
+    lcd_set_backlight(mem_data()->backlight);
 
     if (watchdog_caused_reboot()) {
         debug("reset by watchdog");

src/mem.c

@@ -0,0 +1,73 @@
+/*
+ * mem.c
+ *
+ * Copyright (c) 2023 Thomas Buck (thomas@xythobuz.de)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * See <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+
+#include "hardware/flash.h"
+#include "pico/flash.h"
+
+#include "config.h"
+#include "log.h"
+#include "mem.h"
+
+#define FLASH_LOCK_TIMEOUT_MS 500
+#define FLASH_OFFSET (PICO_FLASH_SIZE_BYTES - FLASH_SECTOR_SIZE)
+
+static struct mem_data data_ram = MEM_DATA_INIT;
+static const uint8_t *data_flash = (const uint8_t *)(XIP_BASE + FLASH_OFFSET);
+
+static_assert(sizeof(struct mem_data) < FLASH_SECTOR_SIZE,
+              "Config needs to fit inside a flash sector");
+
+void mem_init(void) {
+    if (!flash_safe_execute_core_init()) {
+        debug("error calling flash_safe_execute_core_init");
+    }
+
+    const struct mem_data *flash_ptr = (const struct mem_data *)data_flash;
+
+    if (flash_ptr->version == MEM_VERSION) {
+        debug("found matching config (0x%02X)", flash_ptr->version);
+        data_ram = *flash_ptr;
+    } else {
+        debug("invalid config (0x%02X != 0x%02X)", flash_ptr->version, MEM_VERSION);
+    }
+}
+
+static void mem_write_flash(void *param) {
+    flash_range_erase(FLASH_OFFSET, FLASH_SECTOR_SIZE);
+
+    // TODO only need to write with length multiple of FLASH_PAGE_SIZE
+    flash_range_program(FLASH_OFFSET, param, FLASH_SECTOR_SIZE);
+}
+
+void mem_write(void) {
+    if (memcmp(&data_ram, data_flash, sizeof(struct mem_data)) == 0) {
+        debug("no change, skip write");
+        return;
+    }
+
+    int r = flash_safe_execute(mem_write_flash, &data_ram, FLASH_LOCK_TIMEOUT_MS);
+    if (r != PICO_OK) {
+        debug("error calling mem_write_flash: %d", r);
+    }
+}
+
+struct mem_data *mem_data(void) {
+    return &data_ram;
+}

src/menu.c

@@ -22,6 +22,7 @@
 #include "buttons.h"
 #include "text.h"
 #include "lcd.h"
+#include "mem.h"
 #include "menu.h"
 
 static char prev_buff[MENU_MAX_LEN] = {0};
@@ -37,6 +38,7 @@ static void menu_buttons(enum buttons btn, bool state) {
             backlight_value = backlight_value >> 1;
         }
         lcd_set_backlight(backlight_value);
+        mem_data()->backlight = backlight_value;
         return;
     } else if (state && (btn == BTN_RIGHT)) {
         uint16_t backlight_value = lcd_get_backlight();
@@ -44,6 +46,7 @@ static void menu_buttons(enum buttons btn, bool state) {
             backlight_value = backlight_value << 1;
         }
         lcd_set_backlight(backlight_value);
+        mem_data()->backlight = backlight_value;
         return;
     } else if (state && ((btn == BTN_ENTER) || (btn == BTN_A))) {
         if (enter_callback) {
@@ -100,6 +103,7 @@ void menu_init(void (*enter)(int), void (*exit)(void)) {
 
 void menu_deinit(void) {
     buttons_callback(NULL);
+    mem_write();
 }
 
 void menu_run(void (*draw)(struct menu_state *), bool centered) {

src/state_scan.c

@@ -58,8 +58,8 @@ void state_scan_enter(void) {
 }
 
 void state_scan_exit(void) {
-    menu_deinit();
     ble_scan(BLE_SCAN_OFF);
+    menu_deinit();
 }
 
 static void draw(struct menu_state *menu) {