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

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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>
This commit is contained in:
Tejun Heo
2006-05-15 20:57:46 +09:00
parent 838df6284c
commit 34bf21704c
2 changed files with 149 additions and 0 deletions
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6
include/linux/libata.h
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@@ -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 *);