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@xxxxxxxxx>
--- old/drivers/ata/sata_mv.c 2008-05-01 17:56:54.000000000 -0400
+++ linux/drivers/ata/sata_mv.c 2008-05-01 18:01:04.000000000 -0400
@@ -492,6 +492,7 @@
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);
@@ -561,6 +562,7 @@
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,
@@ -579,7 +581,6 @@
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,
@@ -592,7 +593,6 @@
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,
};
@@ -1090,6 +1090,45 @@
}
}
+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;
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