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sata_mv: simplify request/response queue handling
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Try and simplify handling of the request/response queues.

Maintain the cached copies of queue indexes in a fully-masked state,
rather than having each use of them have to do the masking.

Split off handling of a single crpb response into a separate function,
to reduce complexity in the main mv_process_crpb_entries() routine.

Ignore the rarely-valid error bits from the crpb status field,
as we already handle that information in mv_err_intr().

For now, preserve the rest of the original logic.
A later patch will deal with fixing that separately.

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 Apr 25, 2008
1 parent 1cfd19a commit fcfb1f7
Showing 1 changed file with 56 additions and 53 deletions.
109 changes: 56 additions & 53 deletions drivers/ata/sata_mv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -804,7 +804,8 @@ static void mv_set_edma_ptrs(void __iomem *port_mmio,
/*
* initialize request queue
*/
index = (pp->req_idx & MV_MAX_Q_DEPTH_MASK) << EDMA_REQ_Q_PTR_SHIFT;
pp->req_idx &= MV_MAX_Q_DEPTH_MASK; /* paranoia */
index = pp->req_idx << EDMA_REQ_Q_PTR_SHIFT;

WARN_ON(pp->crqb_dma & 0x3ff);
writel((pp->crqb_dma >> 16) >> 16, port_mmio + EDMA_REQ_Q_BASE_HI_OFS);
Expand All @@ -820,7 +821,8 @@ static void mv_set_edma_ptrs(void __iomem *port_mmio,
/*
* initialize response queue
*/
index = (pp->resp_idx & MV_MAX_Q_DEPTH_MASK) << EDMA_RSP_Q_PTR_SHIFT;
pp->resp_idx &= MV_MAX_Q_DEPTH_MASK; /* paranoia */
index = pp->resp_idx << EDMA_RSP_Q_PTR_SHIFT;

WARN_ON(pp->crpb_dma & 0xff);
writel((pp->crpb_dma >> 16) >> 16, port_mmio + EDMA_RSP_Q_BASE_HI_OFS);
Expand Down Expand Up @@ -1312,7 +1314,7 @@ static void mv_qc_prep(struct ata_queued_cmd *qc)
flags |= (qc->dev->link->pmp & 0xf) << CRQB_PMP_SHIFT;

/* get current queue index from software */
in_index = pp->req_idx & MV_MAX_Q_DEPTH_MASK;
in_index = pp->req_idx;

pp->crqb[in_index].sg_addr =
cpu_to_le32(pp->sg_tbl_dma[qc->tag] & 0xffffffff);
Expand Down Expand Up @@ -1404,7 +1406,7 @@ static void mv_qc_prep_iie(struct ata_queued_cmd *qc)
flags |= (qc->dev->link->pmp & 0xf) << CRQB_PMP_SHIFT;

/* get current queue index from software */
in_index = pp->req_idx & MV_MAX_Q_DEPTH_MASK;
in_index = pp->req_idx;

crqb = (struct mv_crqb_iie *) &pp->crqb[in_index];
crqb->addr = cpu_to_le32(pp->sg_tbl_dma[qc->tag] & 0xffffffff);
Expand Down Expand Up @@ -1471,9 +1473,8 @@ static unsigned int mv_qc_issue(struct ata_queued_cmd *qc)

mv_start_dma(ap, port_mmio, pp, qc->tf.protocol);

pp->req_idx++;

in_index = (pp->req_idx & MV_MAX_Q_DEPTH_MASK) << EDMA_REQ_Q_PTR_SHIFT;
pp->req_idx = (pp->req_idx + 1) & MV_MAX_Q_DEPTH_MASK;
in_index = pp->req_idx << EDMA_REQ_Q_PTR_SHIFT;

/* and write the request in pointer to kick the EDMA to life */
writelfl((pp->crqb_dma & EDMA_REQ_Q_BASE_LO_MASK) | in_index,
Expand Down Expand Up @@ -1607,70 +1608,72 @@ static void mv_intr_pio(struct ata_port *ap)
ata_qc_complete(qc);
}

static void mv_intr_edma(struct ata_port *ap)
static void mv_process_crpb_response(struct ata_port *ap,
struct mv_crpb *response, unsigned int tag, int ncq_enabled)
{
struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);

if (qc) {
u8 ata_status;
u16 edma_status = le16_to_cpu(response->flags);
/*
* edma_status from a response queue entry:
* LSB is from EDMA_ERR_IRQ_CAUSE_OFS (non-NCQ only).
* MSB is saved ATA status from command completion.
*/
if (!ncq_enabled) {
u8 err_cause = edma_status & 0xff & ~EDMA_ERR_DEV;
if (err_cause) {
/*
* Error will be seen/handled by mv_err_intr().
* So do nothing at all here.
*/
return;
}
}
ata_status = edma_status >> CRPB_FLAG_STATUS_SHIFT;
qc->err_mask |= ac_err_mask(ata_status);
ata_qc_complete(qc);
} else {
ata_port_printk(ap, KERN_ERR, "%s: no qc for tag=%d\n",
__func__, tag);
}
}

static void mv_process_crpb_entries(struct ata_port *ap, struct mv_port_priv *pp)
{
void __iomem *port_mmio = mv_ap_base(ap);
struct mv_host_priv *hpriv = ap->host->private_data;
struct mv_port_priv *pp = ap->private_data;
struct ata_queued_cmd *qc;
u32 out_index, in_index;
u32 in_index;
bool work_done = false;
int ncq_enabled = (pp->pp_flags & MV_PP_FLAG_NCQ_EN);

/* get h/w response queue pointer */
/* Get the hardware queue position index */
in_index = (readl(port_mmio + EDMA_RSP_Q_IN_PTR_OFS)
>> EDMA_RSP_Q_PTR_SHIFT) & MV_MAX_Q_DEPTH_MASK;

while (1) {
u16 status;
/* Process new responses from since the last time we looked */
while (in_index != pp->resp_idx) {
unsigned int tag;
struct mv_crpb *response = &pp->crpb[pp->resp_idx];

/* get s/w response queue last-read pointer, and compare */
out_index = pp->resp_idx & MV_MAX_Q_DEPTH_MASK;
if (in_index == out_index)
break;
pp->resp_idx = (pp->resp_idx + 1) & MV_MAX_Q_DEPTH_MASK;

/* 50xx: get active ATA command */
if (IS_GEN_I(hpriv))
if (IS_GEN_I(hpriv)) {
/* 50xx: no NCQ, only one command active at a time */
tag = ap->link.active_tag;

/* Gen II/IIE: get active ATA command via tag, to enable
* support for queueing. this works transparently for
* queued and non-queued modes.
*/
else
tag = le16_to_cpu(pp->crpb[out_index].id) & 0x1f;

qc = ata_qc_from_tag(ap, tag);

/* For non-NCQ mode, the lower 8 bits of status
* are from EDMA_ERR_IRQ_CAUSE_OFS,
* which should be zero if all went well.
*/
status = le16_to_cpu(pp->crpb[out_index].flags);
if ((status & 0xff) && !(pp->pp_flags & MV_PP_FLAG_NCQ_EN)) {
mv_err_intr(ap, qc);
return;
}

/* and finally, complete the ATA command */
if (qc) {
qc->err_mask |=
ac_err_mask(status >> CRPB_FLAG_STATUS_SHIFT);
ata_qc_complete(qc);
} else {
/* Gen II/IIE: get command tag from CRPB entry */
tag = le16_to_cpu(response->id) & 0x1f;
}

/* advance software response queue pointer, to
* indicate (after the loop completes) to hardware
* that we have consumed a response queue entry.
*/
mv_process_crpb_response(ap, response, tag, ncq_enabled);
work_done = true;
pp->resp_idx++;
}

/* Update the software queue position index in hardware */
if (work_done)
writelfl((pp->crpb_dma & EDMA_RSP_Q_BASE_LO_MASK) |
(out_index << EDMA_RSP_Q_PTR_SHIFT),
(pp->resp_idx << EDMA_RSP_Q_PTR_SHIFT),
port_mmio + EDMA_RSP_Q_OUT_PTR_OFS);
}

Expand Down Expand Up @@ -1748,7 +1751,7 @@ static void mv_host_intr(struct ata_host *host, u32 relevant, unsigned int hc)

if (pp->pp_flags & MV_PP_FLAG_EDMA_EN) {
if ((DMA_IRQ << hardport) & hc_irq_cause)
mv_intr_edma(ap);
mv_process_crpb_entries(ap, pp);
} else {
if ((DEV_IRQ << hardport) & hc_irq_cause)
mv_intr_pio(ap);
Expand Down

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