/**
 * @file driver.h
 * @brief Kernel driver architecture.
 *
 * Provides a simple framework for registering and initializing kernel drivers.
 * Each driver provides a probe function that returns whether it should load,
 * and an init function that performs the actual initialization.
 *
 * Drivers are registered at compile time using the REGISTER_DRIVER macro,
 * which places driver descriptors in a special linker section. The kernel
 * iterates over all registered drivers during boot.
 */

#ifndef DRIVER_H
#define DRIVER_H

#include <stdint.h>

/** Driver probe result codes. */
typedef enum {
    DRIVER_PROBE_OK = 0,        /**< Driver should be loaded. */
    DRIVER_PROBE_NOT_FOUND = 1, /**< Hardware not found, skip this driver. */
    DRIVER_PROBE_ERROR = 2      /**< Error during probing. */
} driver_probe_result_t;

/**
 * Driver descriptor structure.
 *
 * Each driver provides a name, a probe function (to test if hardware is
 * present), and an init function (to set up the driver).
 */
typedef struct driver {
    const char *name;                     /**< Human-readable driver name. */
    driver_probe_result_t (*probe)(void); /**< Probe function. Returns DRIVER_PROBE_OK if driver should load. */
    int (*init)(void);                    /**< Init function. Returns 0 on success, non-zero on failure. */
} driver_t;

/**
 * Register a driver.
 *
 * Places the driver descriptor in the .drivers linker section so it
 * is automatically discovered during boot.
 */
#define REGISTER_DRIVER(drv) \
    static const driver_t * __attribute__((used, section(".drivers"))) \
    _driver_##drv = &(drv)

/**
 * Initialize all registered drivers.
 *
 * Iterates over the .drivers section, probes each driver, and initializes
 * those that respond positively to probing.
 */
void init_drivers(void);

#endif /* DRIVER_H */