forked from Lephenixnoir/gint
92 lines
3.0 KiB
C
92 lines
3.0 KiB
C
//---
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// gint:drivers - General tools for drivers
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//---
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#ifndef GINT_DRIVERS
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#define GINT_DRIVERS
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#include <gint/defs/attributes.h>
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#include <gint/defs/types.h>
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//---
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// Driver initialization
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//
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// Drivers are initialized in linking order. For each driver, the
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// following functions are called:
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// - driver_sh3() [if running on an SH3-based machine]
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// - ctx_save()
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// - init()
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//
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// When the driver is unloaded, the following functions are called:
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// - ctx_restore()
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//---
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/* gint_driver_t - driver meta-information used by gint */
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typedef struct
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{
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/* Driver name */
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const char *name;
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/* driver_sh3() - rectify driver initialization on SH3 platforms
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This function is called during driver initialization on SH3. It may
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be NULL. */
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void (*driver_sh3)(void);
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/* init() - initialize the driver
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This function is called after ctx_save() and needs not save the
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system setting. It is typically used to initialize registers to
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suitable values on startup. If there is no init function, this field
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may be set to NULL */
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void (*init)(void);
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/* unload() - deinitialize the driver
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This function is called before ctx_restore() when gint is unloaded.
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If there is no unload function, the field may be set to NULL */
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void (*unload)(void);
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/* Size of a context object for the driver */
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uint ctx_size;
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/* System context. The driver has to allocate a buffer of size at least
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ctx_size, where gint stores the system's configuration. It is
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advised to place this buffer in the .gint_bss section using the GBSS
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macro of <defs/attributes.h> if it doesn't need to be initialized */
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void *sys_ctx;
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/* ctx_save() - save the driver's hardware support
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This function is provided by the driver to save the state of its
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hardware support (memory-mapped MPU registers, port state, etc).
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@ctx A buffer of size ctx_size */
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void (*ctx_save)(void *ctx);
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/* ctx_restore() - restore a saved context
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This function is provided by the driver to restore the state saved
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by ctx_save(). It can alter the contents of the buffer freely.
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@ctx A context buffer filled by ctx_save() */
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void (*ctx_restore)(void *ctx);
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} GPACKED(4) gint_driver_t;
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/* GINT_DECLARE_DRIVER() - make a driver visible to gint
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Use this macro to expose a driver by passing it the name of a gint_driver_t
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structure. This macro moves the structure to the .gint.drivers.* sections,
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which are automatically traversed at startup.
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The @level argument represents the priority level: lower numbers mean that
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drivers will be loaded sooner. This numbering allows a primitive form of
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dependency for drivers. You need to specify a level which is strictly
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higher than the level of all the drivers you depend on. */
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#define GINT_DECLARE_DRIVER(level, name) \
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GSECTION(".gint.drivers." #level) extern gint_driver_t name;
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/* GINT_DRIVER_SH3() - declare a function for SH3-rectification
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This macros allows the argument function to not exist on fxcg50. */
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#ifdef FX9860G
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#define GINT_DRIVER_SH3(name) name
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#else
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#define GINT_DRIVER_SH3(name) NULL
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#endif
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#endif /* GINT_DRIVERS */
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