18. IDE Controller Driver¶

Warning

The ATA/IDE Drivers are out of date and should not be used for new BSPs. The preferred alternative is to port the ATA/SATA/SCSI/NVMe support from FreeBSD to RTEMS using the libbsd. Ask on the mailing list if you plan to write a driver for an ATA/IDE device.

18.1. Introduction¶

The IDE Controller driver is responsible for providing an interface to an IDE Controller. The capabilities provided by this driver are:

Read IDE Controller register
Write IDE Controller register
Read data block through IDE Controller Data Register
Write data block through IDE Controller Data Register

The reference implementation for an IDE Controller driver can be found in bsps/shared/dev/ide. This driver is based on the libchip concept and allows to work with any of the IDE Controller chips simply by appropriate configuration of BSP. Drivers for a particular IDE Controller chips locate in the following directories: drivers for well-known IDE Controller chips locate into bsps/shared/dev/ide and drivers for custom IDE Controller chips (for example, implemented on FPGA) locate into bsps/${RTEMS_CPU}/${RTEMS_BSP/ata. There is a README file in these directories for each supported IDE Controller chip. Each of these README explains how to configure a BSP for that particular IDE Controller chip.

18.2. Initialization¶

IDE Controller chips used by a BSP are statically configured into IDE_Controller_Table. The ide_controller_initialize routine is responsible for initialization of all configured IDE controller chips. Initialization order of the chips based on the order the chips are defined in the IDE_Controller_Table.

The following actions are performed by the IDE Controller driver initialization routine:

rtems_device_driver ide_controller_initialize(
  rtems_device_major_number  major,
  rtems_device_minor_number  minor_arg,
  void                      *arg
)
{
  for each IDE Controller chip configured in IDE_Controller_Table
    if (BSP dependent probe(if exists) AND device probe for this IDE chip
        indicates it is present)
      perform initialization of the particular chip
      register device with configured name for this chip
}

18.3. Read IDE Controller Register¶

The ide_controller_read_register routine reads the content of the IDE Controller chip register. IDE Controller chip is selected via the minor number. This routine is not allowed to be called from an application.

void ide_controller_read_register(
  rtems_device_minor_number  minor,
  unsigned32                 reg,
  unsigned32                *value
)
{
  get IDE Controller chip configuration information from
  IDE_Controller_Table by minor number

  invoke read register routine for the chip
}

18.4. Write IDE Controller Register¶

The ide_controller_write_register routine writes IDE Controller chip register with specified value. IDE Controller chip is selected via the minor number. This routine is not allowed to be called from an application.

void ide_controller_write_register(
  rtems_device_minor_number minor,
  unsigned32                reg,
  unsigned32                value
)
{
  get IDE Controller chip configuration information from
  IDE_Controller_Table by minor number

  invoke write register routine for the chip
}

18.5. Read Data Block Through IDE Controller Data Register¶

The ide_controller_read_data_block provides multiple consequent read of the IDE Controller Data Register. IDE Controller chip is selected via the minor number. The same functionality may be achieved via separate multiple calls of ide_controller_read_register routine but ide_controller_read_data_block allows to escape functions call overhead. This routine is not allowed to be called from an application.

void ide_controller_read_data_block(
  rtems_device_minor_number  minor,
  unsigned16                 block_size,
  blkdev_sg_buffer          *bufs,
  uint32_t                  *cbuf,
  uint32_t                  *pos
)
{
  get IDE Controller chip configuration information from
  IDE_Controller_Table by minor number

  invoke read data block routine for the chip
}

18.6. Write Data Block Through IDE Controller Data Register¶

The ide_controller_write_data_block provides multiple consequent write into the IDE Controller Data Register. IDE Controller chip is selected via the minor number. The same functionality may be achieved via separate multiple calls of ide_controller_write_register routine but ide_controller_write_data_block allows to escape functions call overhead. This routine is not allowed to be called from an application.

void ide_controller_write_data_block(
  rtems_device_minor_number  minor,
  unsigned16                 block_size,
  blkdev_sg_buffer          *bufs,
  uint32_t                  *cbuf,
  uint32_t                  *pos
)
{
  get IDE Controller chip configuration information from
  IDE_Controller_Table by minor number

  invoke write data block routine for the chip
}