Bootloader/retention boot mode support

app/CMakeLists.txt

@@ -21,6 +21,7 @@ zephyr_syscall_header(${APPLICATION_SOURCE_DIR}/include/drivers/ext_power.h)
 # Add your source file to the "app" target. This must come after
 # find_package(Zephyr) which defines the target.
 target_include_directories(app PRIVATE include)
+add_subdirectory(src/boot)
 target_sources(app PRIVATE src/stdlib.c)
 target_sources(app PRIVATE src/activity.c)
 target_sources(app PRIVATE src/behavior.c)

app/Kconfig

@@ -513,6 +513,8 @@ endmenu
 
 menu "Advanced"
 
+rsource "src/boot/Kconfig"
+
 menu "Initialization Priorities"
 
 if USB_DEVICE_STACK

app/dts/behaviors/reset.dtsi

@@ -19,6 +19,7 @@
         bootloader: bootload {
             compatible = "zmk,behavior-reset";
             type = <RST_UF2>;
+            bootloader;
             #binding-cells = <0>;
             display-name = "Bootloader";
         };

app/dts/bindings/behaviors/zmk,behavior-reset.yaml

@@ -11,3 +11,5 @@ properties:
   type:
     type: int
     default: 0
+  bootloader:
+    type: boolean

app/dts/bindings/retained_mem/zmk,bootmode-to-magic-mapper.yaml

@@ -0,0 +1,9 @@
+# Copyright (c) 2024 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: |
+  Driver for mapping bootloader boot mode to a magic value
+
+compatible: "zmk,bootmode-to-magic-mapper"
+
+include: base.yaml

app/src/behaviors/behavior_reset.c

@@ -14,11 +14,21 @@
 
 #include <zmk/behavior.h>
 
+#if IS_ENABLED(CONFIG_RETENTION_BOOT_MODE)
+
+#include <zephyr/retention/bootmode.h>
+
+#endif /* IS_ENABLED(CONFIG_RETENTION_BOOT_MODE) */
+
 LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 #if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
 struct behavior_reset_config {
+#if IS_ENABLED(CONFIG_RETENTION_BOOT_MODE)
+    enum BOOT_MODE_TYPES boot_mode;
+#else
     int type;
+#endif /* IS_ENABLED(CONFIG_RETENTION_BOOT_MODE) */
 };
 
 static int behavior_reset_init(const struct device *dev) { return 0; };
@@ -28,10 +38,20 @@ static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
     const struct device *dev = zmk_behavior_get_binding(binding->behavior_dev);
     const struct behavior_reset_config *cfg = dev->config;
 
-    // TODO: Correct magic code for going into DFU?
+#if IS_ENABLED(CONFIG_RETENTION_BOOT_MODE)
+    int ret = bootmode_set(cfg->boot_mode);
+    if (ret < 0) {
+        LOG_ERR("Failed to set the bootloader mode (%d)", ret);
+        return ZMK_BEHAVIOR_OPAQUE;
+    }
+
+    sys_reboot(SYS_REBOOT_WARM);
+#else
     // See
     // https://github.com/adafruit/Adafruit_nRF52_Bootloader/blob/d6b28e66053eea467166f44875e3c7ec741cb471/src/main.c#L107
     sys_reboot(cfg->type);
+#endif /* IS_ENABLED(CONFIG_RETENTION_BOOT_MODE) */
+
     return ZMK_BEHAVIOR_OPAQUE;
 }
 
@@ -45,7 +65,11 @@ static const struct behavior_driver_api behavior_reset_driver_api = {
 
 #define RST_INST(n)                                                                                \
     static const struct behavior_reset_config behavior_reset_config_##n = {                        \
-        .type = DT_INST_PROP(n, type)};                                                            \
+        COND_CODE_1(                                                                               \
+            IS_ENABLED(CONFIG_RETENTION_BOOT_MODE),                                                \
+            (DT_INST_PROP(n, bootloader) ? BOOT_MODE_TYPE_BOOTLOADER : BOOT_MODE_TYPE_NORMAL),     \
+            (.type = DT_INST_PROP(n, type))),                                                      \
+    };                                                                                             \
     BEHAVIOR_DT_INST_DEFINE(n, behavior_reset_init, NULL, NULL, &behavior_reset_config_##n,        \
                             POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,                      \
                             &behavior_reset_driver_api);

app/src/boot/CMakeLists.txt

@@ -0,0 +1,2 @@
+
+target_sources_ifdef(CONFIG_ZMK_BOOTMODE_TO_MAGIC_VALUE_MAPPER app PRIVATE bootmode_to_magic_mapper.c)

app/src/boot/Kconfig

@@ -0,0 +1,32 @@
+
+config ZMK_BOOTMODE_TO_MAGIC_VALUE_MAPPER
+    bool "Magic Value Mapper"
+    default y
+    depends on DT_HAS_ZMK_BOOTMODE_TO_MAGIC_MAPPER_ENABLED
+
+if ZMK_BOOTMODE_TO_MAGIC_VALUE_MAPPER
+
+choice ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE
+    prompt "Magic Value Bootloader Type"
+
+config ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE_UNKNOWN
+    bool "Unknown"
+
+config ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE_TINYUF2
+    bool "tinyuf2"
+
+config ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE_ADAFRUIT_BOSSA
+    bool "Adafruit BOSSA"
+
+
+config ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE_ADAFRUIT_NRF52
+    bool "Adafruit nRF52"
+
+endchoice
+
+config ZMK_BOOTMODE_BOOTLOADER_MAGIC_VALUE
+    hex
+    default 0xf01669ef if ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE_TINYUF2 || ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE_ADAFRUIT_BOSSA || BOOTLOADER_BOSSA_ADAFRUIT_UF2
+    default 0x57 if ZMK_BOOTMODE_MAGIC_VALUE_BOOTLOADER_TYPE_ADAFRUIT_NRF52
+
+endif

app/src/boot/bootmode_to_magic_mapper.c

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2024 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_bootmode_to_magic_mapper
+
+#include <zephyr/device.h>
+#include <zephyr/retention/bootmode.h>
+#include <zephyr/retention/retention.h>
+#include <zephyr/drivers/retained_mem.h>
+
+static const struct device *magic_dev = DEVICE_DT_GET(DT_CHOSEN(zmk_magic_boot_mode));
+static const uint32_t bootloader_magic_value = CONFIG_ZMK_BOOTMODE_BOOTLOADER_MAGIC_VALUE;
+
+static ssize_t btmm_ram_size(const struct device *dev) { return (ssize_t)1; }
+
+static int btmm_ram_read(const struct device *dev, off_t offset, uint8_t *buffer, size_t size) {
+    if (size != 1) {
+        return -ENOTSUP;
+    }
+
+    uint32_t val;
+    int ret = retention_read(magic_dev, 0, (uint8_t *)&val, sizeof(val));
+    if (ret < 0) {
+        return ret;
+    }
+
+    *buffer = (val == bootloader_magic_value) ? BOOT_MODE_TYPE_BOOTLOADER : BOOT_MODE_TYPE_NORMAL;
+
+    return 0;
+}
+
+static int btmm_ram_write(const struct device *dev, off_t offset, const uint8_t *buffer,
+                          size_t size) {
+    if (size != 1) {
+        return -ENOTSUP;
+    }
+
+    uint32_t val = (*buffer == BOOT_MODE_TYPE_BOOTLOADER) ? bootloader_magic_value : 0;
+
+    return retention_write(magic_dev, 0, (uint8_t *)&val, sizeof(val));
+}
+
+static int btmm_ram_clear(const struct device *dev) { return retention_clear(magic_dev); }
+
+static const struct retained_mem_driver_api btmm_api = {
+    .size = btmm_ram_size,
+    .read = btmm_ram_read,
+    .write = btmm_ram_write,
+    .clear = btmm_ram_clear,
+};
+
+DEVICE_DT_INST_DEFINE(0, NULL, NULL, NULL, NULL, POST_KERNEL, 0, &btmm_api);

app/west.yml

@@ -4,10 +4,12 @@ manifest:
       url-base: https://github.com/zephyrproject-rtos
     - name: zmkfirmware
       url-base: https://github.com/zmkfirmware
+    - name: petejohanson
+      url-base: https://github.com/petejohanson
   projects:
     - name: zephyr
-      remote: zmkfirmware
-      revision: v3.5.0+zmk-fixes
+      remote: petejohanson
+      revision: 3.5-stm32-bootloader-support
       clone-depth: 1
       import:
         name-blocklist: