libata: separate out ata_std_prereset() from ata_sff_prereset()

Separate out generic ATA portion from ata_sff_prereset() into
ata_std_prereset() and implement ata_sff_prereset() using the std
version.  Waiting for device readiness is the only SFF specific part.

ata_base_port_ops now has ata_std_prereset() for its prereset and
ata_sff_port_ops overrides it to ata_sff_prereset().  This change can
affect pdc_adma, ahci, sata_fsl and sata_sil24.  pdc_adma implements
its own prereset using ata_sff_prereset() and the rest has hardreset
and thus are unaffected by this change.

This change reflects real world situation.  There is no generic way to
wait for device readiness for non-SFF controllers and some of them
don't have any mechanism for that.  Non-sff drivers which don't have
hardreset should wrap ata_std_prereset() and wait for device readiness
itself but there's no such driver now and isn't likely to be popular
in the future either.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 603712b59cf3..595ede55fe4c 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -824,6 +824,7 @@ static inline int ata_port_is_dummy(struct ata_port *ap)
 extern void sata_print_link_status(struct ata_link *link);
 extern void ata_port_probe(struct ata_port *);
 extern int sata_set_spd(struct ata_link *link);
+extern int ata_std_prereset(struct ata_link *link, unsigned long deadline);
 extern int sata_link_debounce(struct ata_link *link,
                         const unsigned long *params, unsigned long deadline);
 extern int sata_link_resume(struct ata_link *link, const unsigned long *params,