126 lines
4.6 KiB
C
126 lines
4.6 KiB
C
//---
|
|
// gint:drivers - General tools for drivers
|
|
//---
|
|
|
|
#ifndef GINT_DRIVERS
|
|
#define GINT_DRIVERS
|
|
|
|
#include <gint/defs/attributes.h>
|
|
#include <gint/defs/types.h>
|
|
|
|
//---
|
|
// Driver procedure flow
|
|
//
|
|
// Drivers are initialized in priority order, and in linking order within
|
|
// the same priority level (pretty much undefined). Make sure every
|
|
// driver's priority level is higher than those of its dependencies.
|
|
//
|
|
// At initialization, the following functions are called:
|
|
// 1. driver_sh3() [if not NULL, SH3 fx9860g only]
|
|
// 2. ctx_save(sys_ctx) [if not NULL]
|
|
// 3. init() [if not NULL]
|
|
//
|
|
// Then, if the on-screen boot log is enabled, the status() function is
|
|
// called and the returned string is displayed (21 characters max).
|
|
// 4. status() [if not NULL, if GINT_BOOT_LOG is defined]
|
|
//
|
|
// If the gint_switch() function is called to temporarily give back
|
|
// control to the operating system, the state of each driver is saved to
|
|
// the stack, then restored from there.
|
|
// 5. ctx_save(stack) [if not NULL]
|
|
// 6. ctx_restore(stack) [if not NULL]
|
|
//
|
|
// When finally the driver is unloaded, the system context is restored.
|
|
// 7. ctx_restore(sys_ctx) [if not NULL]
|
|
//---
|
|
|
|
/* gint_driver_t - driver meta-information used by gint */
|
|
typedef struct
|
|
{
|
|
/* Driver name */
|
|
const char *name;
|
|
|
|
/* driver_sh3() - rectify driver initialization on SH3 platforms
|
|
This function is called during driver initialization on SH3. It may
|
|
be NULL. */
|
|
void (*driver_sh3)(void);
|
|
|
|
/* init() - initialize the driver
|
|
This function is called after ctx_save() and needs not save the
|
|
system setting. It is typically used to initialize registers to
|
|
suitable values on startup. If there is no init function, this field
|
|
may be set to NULL */
|
|
void (*init)(void);
|
|
|
|
/* unload() - deinitialize the driver
|
|
This function is called before ctx_restore() when gint is unloaded.
|
|
If there is no unload function, the field may be set to NULL */
|
|
void (*unload)(void);
|
|
|
|
/* Size of a context object for the driver */
|
|
uint ctx_size;
|
|
|
|
/* System context. The driver has to allocate a buffer of size at least
|
|
ctx_size, where gint stores the system's configuration. It is
|
|
advised to place this buffer in the .gint_bss section using the GBSS
|
|
macro of <defs/attributes.h> if it doesn't need to be initialized */
|
|
void *sys_ctx;
|
|
|
|
/* ctx_save() - save the driver's hardware support
|
|
This function is provided by the driver to save the state of its
|
|
hardware support (memory-mapped MPU registers, port state, etc).
|
|
@ctx A buffer of size ctx_size */
|
|
void (*ctx_save)(void *ctx);
|
|
|
|
/* ctx_restore() - restore a saved context
|
|
This function is provided by the driver to restore the state saved
|
|
by ctx_save(). It can alter the contents of the buffer freely.
|
|
@ctx A context buffer filled by ctx_save() */
|
|
void (*ctx_restore)(void *ctx);
|
|
|
|
/* status() - status string generation
|
|
When the boot log is defined, this function is called to print
|
|
information returned by the driver, for debugging purposes. This is
|
|
expected to be a short (max 21 bytes) string because only a few
|
|
lines are available for all drivers.
|
|
Returns a pointer to a string; a static buffer is suitable. */
|
|
const char * (*status)(void);
|
|
|
|
} GPACKED(4) gint_driver_t;
|
|
|
|
/* GINT_DECLARE_DRIVER() - make a driver visible to gint
|
|
|
|
Use this macro to expose a driver by passing it the name of a gint_driver_t
|
|
structure. This macro moves the structure to the .gint.drivers.* sections,
|
|
which are automatically traversed at startup.
|
|
|
|
The @level argument represents the priority level: lower numbers mean that
|
|
drivers will be loaded sooner. This numbering allows a primitive form of
|
|
dependency for drivers. You need to specify a level which is strictly
|
|
higher than the level of all the drivers you depend on. */
|
|
#define GINT_DECLARE_DRIVER(level, name) \
|
|
GSECTION(".gint.drivers." #level) extern gint_driver_t name;
|
|
|
|
/* GINT_DRIVER_SH3() - declare a function for SH3-rectification
|
|
This macro makes its argument NULL on fxcg50, this way the named function
|
|
can be defined under #ifdef FX9860G while keeping the structure clean. */
|
|
|
|
#ifdef FXCG50
|
|
#define GINT_DRIVER_SH3(name) NULL
|
|
#else
|
|
#define GINT_DRIVER_SH3(name) name
|
|
#endif
|
|
|
|
/* GINT_DRIVER_STATUS() - declare a function for status string generation
|
|
This macro makes its argument NULL when GINT_BOOT_LOG is defuned, this way
|
|
the named function can be defined under #ifdef GINT_BOOT_LOG while keeping
|
|
the structure clean. */
|
|
|
|
#ifdef GINT_BOOT_LOG
|
|
#define GINT_DRIVER_STATUS(name) name
|
|
#else
|
|
#define GINT_DRIVER_STATUS(name) NULL
|
|
#endif
|
|
|
|
#endif /* GINT_DRIVERS */
|