[PATCH] libata: implement new SCR handling and port on/offline functions

Implement ata_scr_{valid|read|write|write_flush}() and
ata_port_{online|offline}().  These functions replace
scr_{read|write}() and sata_dev_present().

Major difference between between the new SCR functions and the old
ones is that the new ones have a way to signal error to the caller.
This makes handling SCR-available and SCR-unavailable cases in the
same path easier.  Also, it eases later PM implementation where SCR
access can fail due to various reasons.

ata_port_{online|offline}() functions return 1 only when they are
affirmitive of the condition.  e.g.  if SCR is unaccessible or
presence cannot be determined for other reasons, these functions
return 0.  So, ata_port_online() != !ata_port_offline().  This
distinction is useful in many exception handling cases.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index a4b8a419caad..47b97157995d 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -536,6 +536,12 @@ extern int ata_scsi_ioctl(struct scsi_device *dev, int cmd, void __user *arg);
 extern int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *));
 extern int ata_scsi_release(struct Scsi_Host *host);
 extern unsigned int ata_host_intr(struct ata_port *ap, struct ata_queued_cmd *qc);
+extern int sata_scr_valid(struct ata_port *ap);
+extern int sata_scr_read(struct ata_port *ap, int reg, u32 *val);
+extern int sata_scr_write(struct ata_port *ap, int reg, u32 val);
+extern int sata_scr_write_flush(struct ata_port *ap, int reg, u32 val);
+extern int ata_port_online(struct ata_port *ap);
+extern int ata_port_offline(struct ata_port *ap);
 extern int ata_scsi_device_resume(struct scsi_device *);
 extern int ata_scsi_device_suspend(struct scsi_device *, pm_message_t state);
 extern int ata_device_resume(struct ata_port *, struct ata_device *);