ata_dev_identify — obtain IDENTIFY x DEVICE page
void ata_dev_identify (struct ata_port * ap, unsigned int device);
apport on which device we wish to probe resides
devicedevice bus address, starting at zero
Following bus reset, we issue the IDENTIFY [PACKET] DEVICE command, and read back the 512-byte device information page. The device information page is fed to us via the standard PIO-IN protocol, but we hand-code it here. (TODO: investigate using standard PIO-IN paths)
After reading the device information page, we use several bits of information from it to initialize data structures that will be used during the lifetime of the ata_device. Other data from the info page is used to disqualify certain older ATA devices we do not wish to support.