libata-link: introduce ata_link

Introduce ata_link.  It abstracts PHY and sits between ata_port and
ata_device.  This new level of abstraction is necessary to support
SATA Port Multiplier, which basically adds a bunch of links (PHYs) to
a ATA host port.  Fields related to command execution, spd_limit and
EH are per-link and thus moved to ata_link.

This patch only defines the host link.  Multiple link handling will be
added later.  Also, a lot of ap->link derefences are added but many of
them will be removed as each part is converted to deal directly with
ata_link instead of ata_port.

This patch introduces no behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/ata/pata_scc.c b/drivers/ata/pata_scc.c
index 2d048ef25a5a..aab068fbb7bc 100644
--- a/drivers/ata/pata_scc.c
+++ b/drivers/ata/pata_scc.c
@@ -785,7 +785,7 @@ static u8 scc_bmdma_status (struct ata_port *ap)
 static void scc_data_xfer (struct ata_device *adev, unsigned char *buf,
                            unsigned int buflen, int write_data)
 {
-        struct ata_port *ap = adev->ap;
+        struct ata_port *ap = adev->link->ap;
         unsigned int words = buflen >> 1;
         unsigned int i;
         u16 *buf16 = (u16 *) buf;