Kernel improvements (#468)

* **New Features**
  * Plugin-style modules for platforms and devices with start/stop lifecycle and a runtime-consumable device tree array.

* **Refactor**
  * Consolidated initialization into a kernel/module startup flow.
  * Generated devicetree artifacts moved to the build Generated directory.

* **Changes**
  * Removed legacy no-op registration hooks and I2C lock/unlock wrappers.
  * Driver ownership and private state moved to explicit module/owner model.
  * Added ERROR_NOT_ALLOWED error code.

Platforms/PlatformEsp32/Include/tactility/drivers/esp32_i2c.h

@@ -18,8 +18,6 @@ struct Esp32I2cConfig {
 };
 
 error_t esp32_i2c_get_port(struct Device* device, i2c_port_t* port);
-void esp32_i2c_lock(struct Device* device);
-void esp32_i2c_unlock(struct Device* device);
 
 #ifdef __cplusplus
 }

Platforms/PlatformEsp32/Source/drivers/esp32_gpio.cpp

@@ -107,6 +107,8 @@ const static GpioControllerApi esp32_gpio_api  = {
     .get_options = get_options
 };
 
+extern struct Module platform_module;
+
 Driver esp32_gpio_driver = {
     .name = "esp32_gpio",
     .compatible = (const char*[]) { "espressif,esp32-gpio", nullptr },
@@ -114,7 +116,8 @@ Driver esp32_gpio_driver = {
     .stopDevice = stop,
     .api =  (void*)&esp32_gpio_api,
     .deviceType = nullptr,
-    .internal = { 0 }
+    .owner = &platform_module,
+    .driver_private = nullptr
 };
 
 } // extern "C"

Platforms/PlatformEsp32/Source/drivers/esp32_i2c.cpp

@@ -150,14 +150,6 @@ error_t esp32_i2c_get_port(struct Device* device, i2c_port_t* port) {
     return ERROR_NONE;
 }
 
-void esp32_i2c_lock(struct Device* device) {
-    mutex_lock(&GET_DATA(device)->mutex);
-}
-
-void esp32_i2c_unlock(struct Device* device) {
-    mutex_unlock(&GET_DATA(device)->mutex);
-}
-
 static error_t start(Device* device) {
     ESP_LOGI(TAG, "start %s", device->name);
     auto dts_config = GET_CONFIG(device);
@@ -214,6 +206,8 @@ const static I2cControllerApi esp32_i2c_api = {
     .write_register = write_register
 };
 
+extern struct Module platform_module;
+
 Driver esp32_i2c_driver = {
     .name = "esp32_i2c",
     .compatible = (const char*[]) { "espressif,esp32-i2c", nullptr },
@@ -221,7 +215,8 @@ Driver esp32_i2c_driver = {
     .stopDevice = stop,
     .api = (void*)&esp32_i2c_api,
     .deviceType = &I2C_CONTROLLER_TYPE,
-    .internal = { 0 }
+    .owner = &platform_module,
+    .driver_private = nullptr
 };
 
 } // extern "C"

Platforms/PlatformEsp32/Source/drivers/register.cpp

@@ -1,13 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-#include <tactility/driver.h>
-
-extern "C" {
-
-extern void register_platform_drivers() {
-    extern Driver esp32_gpio_driver;
-    driver_construct(&esp32_gpio_driver);
-    extern Driver esp32_i2c_driver;
-    driver_construct(&esp32_i2c_driver);
-}
-
-}

Platforms/PlatformEsp32/Source/module.cpp

@@ -0,0 +1,33 @@
+#include <tactility/check.h>
+#include <tactility/driver.h>
+#include <tactility/module.h>
+
+extern "C" {
+
+extern Driver esp32_gpio_driver;
+extern Driver esp32_i2c_driver;
+
+static error_t start() {
+    /* We crash when construct fails, because if a single driver fails to construct,
+     * there is no guarantee that the previously constructed drivers can be destroyed */
+    check(driver_construct(&esp32_gpio_driver) == ERROR_NONE);
+    check(driver_construct(&esp32_i2c_driver) == ERROR_NONE);
+    return ERROR_NONE;
+}
+
+static error_t stop() {
+    /* We crash when destruct fails, because if a single driver fails to destruct,
+     * there is no guarantee that the previously destroyed drivers can be recovered */
+    check(driver_destruct(&esp32_gpio_driver) == ERROR_NONE);
+    check(driver_destruct(&esp32_i2c_driver) == ERROR_NONE);
+    return ERROR_NONE;
+}
+
+// The name must be exactly "platform_module"
+struct Module platform_module = {
+    .name = "ESP32 Platform",
+    .start = start,
+    .stop = stop
+};
+
+}

Platforms/PlatformPosix/Source/Register.cpp

@@ -1,10 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-#include <tactility/driver.h>
-
-extern "C" {
-
-extern void register_platform_drivers() {
-    /* Placeholder */
-}
-
-}

Platforms/PlatformPosix/Source/module.cpp

@@ -0,0 +1,22 @@
+#include <tactility/module.h>
+
+extern "C" {
+
+static error_t start() {
+    /* NO-OP for now */
+    return ERROR_NONE;
+}
+
+static error_t stop() {
+    /* NO-OP for now */
+    return ERROR_NONE;
+}
+
+// The name must be exactly "platform_module"
+struct Module platform_module = {
+    .name = "POSIX Platform",
+    .start = start,
+    .stop = stop
+};
+
+}