From 31f88384443b3e0d7e2c9d36a96647b7e82edad3 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 23 Sep 2007 13:19:54 +0900 Subject: libata-pmp: implement qc_defer for command switching PMP support Implement sata_pmp_qc_defer_cmd_switch() - standard qc_defer for command switching PMP support. Signed-off-by: Tejun Heo Signed-off-by: Jeff Garzik --- drivers/ata/libata-pmp.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'drivers/ata/libata-pmp.c') diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c index eeffce636d0..f6c4b11336e 100644 --- a/drivers/ata/libata-pmp.c +++ b/drivers/ata/libata-pmp.c @@ -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 -- cgit v1.2.3