RAM Disk Device

Collaboration diagram for RAM Disk Device:

Data Structures
struct	rtems_ramdisk_config
	RAM disk configuration table entry. More...
struct	ramdisk
	RAM disk descriptor. More...
Static Configuration
typedef struct rtems_ramdisk_config	rtems_ramdisk_config
	RAM disk configuration table entry.
rtems_ramdisk_config	rtems_ramdisk_configuration []
	External reference to the RAM disk configuration table describing each RAM disk in the system.
size_t	rtems_ramdisk_configuration_size
	External reference the size of the RAM disk configuration table rtems_ramdisk_configuration.
rtems_device_driver	ramdisk_initialize (rtems_device_major_number major, rtems_device_minor_number minor, void *arg)
	RAM disk driver initialization entry point.
#define	RAMDISK_DRIVER_TABLE_ENTRY
	RAM disk driver table entry.
#define	RAMDISK_DEVICE_BASE_NAME   "/dev/rd"
Runtime Configuration
typedef struct ramdisk	ramdisk
	RAM disk descriptor.
const rtems_driver_address_table	ramdisk_ops
int	ramdisk_ioctl (rtems_disk_device *dd, uint32_t req, void *argp)
ramdisk *	ramdisk_allocate (void *area_begin, uint32_t media_block_size, rtems_blkdev_bnum media_block_count, bool trace)
	Allocates and initializes a RAM disk descriptor.
void	ramdisk_free (ramdisk *rd)
rtems_status_code	ramdisk_register (uint32_t media_block_size, rtems_blkdev_bnum media_block_count, bool trace, const char *disk, dev_t *dev)
	Allocates, initializes and registers a RAM disk.

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Define Documentation

#define RAMDISK_DRIVER_TABLE_ENTRY

Value:

{ \
    .initialization_entry = ramdisk_initialize, \
    RTEMS_GENERIC_BLOCK_DEVICE_DRIVER_ENTRIES \
  }

RAM disk driver table entry.

---

Function Documentation

ramdisk* ramdisk_allocate	(	void *	area_begin,
		uint32_t	media_block_size,
		rtems_blkdev_bnum	media_block_count,
		bool	trace
	)

Allocates and initializes a RAM disk descriptor.

The block size will be media_block_size. The block count will be media_block_count. The disk storage area begins at area_begin. If area_begin is NULL, the memory will be allocated and zeroed. Sets the trace enable to trace.

Returns:

Pointer to allocated and initialized ramdisk structure, or NULL if no memory is available.

Note:

Runtime configuration example:

 #include <rtems/ramdisk.h>

 rtems_status_code create_ramdisk(
   const char *device,
   uint32_t media_block_size,
   rtems_blkdev_bnum media_block_count
 )
 {
   rtems_status_code sc;
   ramdisk *rd;

   rd = ramdisk_allocate(NULL, media_block_size, media_block_count, false);
   if (rd != NULL) {
     sc = rtems_blkdev_create(
       device,
       media_block_size,
       media_block_count,
       ramdisk_ioctl,
       rd
     );
   } else {
     sc = RTEMS_UNSATISFIED;
   }

   return sc;
 }

rtems_status_code ramdisk_register	(	uint32_t	media_block_size,
		rtems_blkdev_bnum	media_block_count,
		bool	trace,
		const char *	disk,
		dev_t *	dev
	)

Allocates, initializes and registers a RAM disk.

The block size will be media_block_size. The block count will be media_block_count. The disk storage will be allocated. Sets the trace enable to trace. Registers a device node with disk name path disk. The registered device number will be returned in dev.

Return values:

RTEMS_SUCCESSFUL	Successful operation.
RTEMS_UNSATISFIED	Something is wrong.

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Variable Documentation

rtems_ramdisk_config rtems_ramdisk_configuration[]

External reference to the RAM disk configuration table describing each RAM disk in the system.

The configuration table is provided by the application.

size_t rtems_ramdisk_configuration_size

External reference the size of the RAM disk configuration table rtems_ramdisk_configuration.

The configuration table size is provided by the application.