From 31f88384443b3e0d7e2c9d36a96647b7e82edad3 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 23 Sep 2007 13:19:54 +0900 Subject: [PATCH] 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-core.c | 1 + drivers/ata/libata-pmp.c | 30 ++++++++++++++++++++++++++++++ include/linux/libata.h | 1 + 3 files changed, 32 insertions(+) diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index d3e78d97529d..5532a6564d05 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -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); diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c index eeffce636d0c..f6c4b11336e9 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 diff --git a/include/linux/libata.h b/include/linux/libata.h index 3cfdb5f67621..ca296a575c4a 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -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); -- GitLab