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libata-pmp: implement qc_defer for command switching PMP support

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Implement sata_pmp_qc_defer_cmd_switch() - standard qc_defer for
command switching PMP support.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Tejun Heo 2007-09-23 13:19:54 +09:00 committed by Jeff Garzik
parent d0df8b5d0f
commit 31f8838444
3 changed files with 32 additions and 0 deletions
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1
drivers/ata/libata-core.c
View File

@ -7303,6 +7303,7 @@ EXPORT_SYMBOL_GPL(ata_pci_default_filter);
EXPORT_SYMBOL_GPL(ata_pci_clear_simplex);
#endif /* CONFIG_PCI */
EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch);
EXPORT_SYMBOL_GPL(sata_pmp_read_init_tf);
EXPORT_SYMBOL_GPL(sata_pmp_read_val);
EXPORT_SYMBOL_GPL(sata_pmp_write_init_tf);

30
drivers/ata/libata-pmp.c
View File

@ -69,6 +69,36 @@ static int sata_pmp_write(struct ata_link *link, int reg, u32 val)
return rc;
}
/**
* sata_pmp_qc_defer_cmd_switch - qc_defer for command switching PMP
* @qc: ATA command in question
*
* A host which has command switching PMP support cannot issue
* commands to multiple links simultaneously.
*
* LOCKING:
* spin_lock_irqsave(host lock)
*
* RETURNS:
* ATA_DEFER_* if deferring is needed, 0 otherwise.
*/
int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
{
struct ata_link *link = qc->dev->link;
struct ata_port *ap = link->ap;
if (ap->excl_link == NULL || ap->excl_link == link) {
if (ap->nr_active_links == 0 || ata_link_active(link)) {
qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
return ata_std_qc_defer(qc);
}
ap->excl_link = link;
}
return ATA_DEFER_PORT;
}
/**
* sata_pmp_read_init_tf - initialize TF for PMP read
* @tf: taskfile to initialize

1
include/linux/libata.h
View File

@ -947,6 +947,7 @@ extern unsigned long ata_pci_default_filter(struct ata_device *, unsigned long);
/*
* PMP
*/
extern int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc);
extern void sata_pmp_read_init_tf(struct ata_taskfile *tf,
struct ata_device *dev, int pmp, int reg);
extern u32 sata_pmp_read_val(const struct ata_taskfile *tf);