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sata_mv new mv_qc_defer method
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The EDMA engine cannot tolerate a mix of NCQ/non-NCQ commands,
and cannot be used for PIO at all.  So we need to prevent libata
from trying to feed us such mixtures.

Introduce mv_qc_defer() for this purpose, and use it for all chip versions.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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Mark Lord authored and Jeff Garzik committed May 6, 2008
1 parent 9b2c4e0 commit 3e4a139
Showing 1 changed file with 41 additions and 2 deletions.
43 changes: 41 additions & 2 deletions drivers/ata/sata_mv.c
Original file line number Diff line number Diff line change
Expand Up @@ -492,6 +492,7 @@ static int mv5_scr_read(struct ata_port *ap, unsigned int sc_reg_in, u32 *val);
static int mv5_scr_write(struct ata_port *ap, unsigned int sc_reg_in, u32 val);
static int mv_port_start(struct ata_port *ap);
static void mv_port_stop(struct ata_port *ap);
static int mv_qc_defer(struct ata_queued_cmd *qc);
static void mv_qc_prep(struct ata_queued_cmd *qc);
static void mv_qc_prep_iie(struct ata_queued_cmd *qc);
static unsigned int mv_qc_issue(struct ata_queued_cmd *qc);
Expand Down Expand Up @@ -561,6 +562,7 @@ static struct scsi_host_template mv6_sht = {
static struct ata_port_operations mv5_ops = {
.inherits = &ata_sff_port_ops,

.qc_defer = mv_qc_defer,
.qc_prep = mv_qc_prep,
.qc_issue = mv_qc_issue,

Expand All @@ -579,7 +581,6 @@ static struct ata_port_operations mv5_ops = {

static struct ata_port_operations mv6_ops = {
.inherits = &mv5_ops,
.qc_defer = sata_pmp_qc_defer_cmd_switch,
.dev_config = mv6_dev_config,
.scr_read = mv_scr_read,
.scr_write = mv_scr_write,
Expand All @@ -592,7 +593,6 @@ static struct ata_port_operations mv6_ops = {

static struct ata_port_operations mv_iie_ops = {
.inherits = &mv6_ops,
.qc_defer = ata_std_qc_defer, /* FIS-based switching */
.dev_config = ATA_OP_NULL,
.qc_prep = mv_qc_prep_iie,
};
Expand Down Expand Up @@ -1090,6 +1090,45 @@ static void mv6_dev_config(struct ata_device *adev)
}
}

static int mv_qc_defer(struct ata_queued_cmd *qc)
{
struct ata_link *link = qc->dev->link;
struct ata_port *ap = link->ap;
struct mv_port_priv *pp = ap->private_data;

/*
* If the port is completely idle, then allow the new qc.
*/
if (ap->nr_active_links == 0)
return 0;

if (pp->pp_flags & MV_PP_FLAG_EDMA_EN) {
/*
* The port is operating in host queuing mode (EDMA).
* It can accomodate a new qc if the qc protocol
* is compatible with the current host queue mode.
*/
if (pp->pp_flags & MV_PP_FLAG_NCQ_EN) {
/*
* The host queue (EDMA) is in NCQ mode.
* If the new qc is also an NCQ command,
* then allow the new qc.
*/
if (qc->tf.protocol == ATA_PROT_NCQ)
return 0;
} else {
/*
* The host queue (EDMA) is in non-NCQ, DMA mode.
* If the new qc is also a non-NCQ, DMA command,
* then allow the new qc.
*/
if (qc->tf.protocol == ATA_PROT_DMA)
return 0;
}
}
return ATA_DEFER_PORT;
}

static void mv_config_fbs(void __iomem *port_mmio, int enable_fbs)
{
u32 old_fiscfg, new_fiscfg, old_ltmode, new_ltmode;
Expand Down

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