* kern/disk.c (grub_disk_firmware_fini)
(grub_disk_firmware_is_tainted): New variables.
* include/grub/disk.h (grub_disk_firmware_fini)
(grub_disk_firmware_is_tainted): Likewise.
* disk/i386/pc/biosdisk.c (GRUB_MOD_FINI(biosdisk)): Moved from here ...
(grub_disk_biosdisk_fini): ... to here.
(GRUB_MOD_FINI(biosdisk)): Implement using grub_disk_biosdisk_fini().
(GRUB_MOD_INIT(biosdisk)): Abort when `grub_disk_firmware_is_tainted'
is set. Register grub_disk_biosdisk_fini() in
`grub_disk_firmware_fini'.
* disk/ata.c: Remove `<grub/machine/biosdisk.h>'.
(GRUB_MOD_INIT(ata)): Remove grub_biosdisk_fini() call.
Use `grub_disk_firmware_is_tainted' and `grub_disk_firmware_fini'
to finish existing firmware disk interface.
* conf/i386-linuxbios.rmk (pkgdata_MODULES): Add `ata.mod'.
(ata_mod_SOURCES): New variable.
(ata_mod_CFLAGS): Likewise.
(ata_mod_LDFLAGS): Likewise.
* disk/ata.c (grub_ata_pio_read): Don't wait for the command to
become activate.
(grub_ata_pio_write): Likewise.
(grub_atapi_identify): Wait after issuing an ATA command.
(grub_atapi_packet): Likewise.
(grub_ata_identify): Likewise.
(grub_ata_readwrite): Likewise.
* disk/ata.c (grub_ata_pio_read): Detect and return the error code.
(grub_ata_pio_write): Likewise.
(grub_ata_readwrite): Use `grub_error', instead of
returning `grub_errno'.
