On 12-08-07 02:17 PM, Mark Lord wrote:
..
> Say, here's a thought: We could get rid of (or relocate to upper layers)
> the busy-wait by having something similar get called from ata_qc_defer().
>
> If you are feeling adventurous, here is a 100% untested patch to do just that.
> It looks correct to me, it compiles, but that's all I can say.
Whoops.. return codes were reversed.
Here's the corrected patch.
The attached copy is the better one to use -- my mailer mangles inline patches.
--- linux-3.4.4/drivers/ata/sata_mv.c 2012-06-22 14:37:50.000000000 -0400
+++ linux/drivers/ata/sata_mv.c 2012-08-07 14:14:43.554503157 -0400
@@ -1388,6 +1388,17 @@
}
}
+static int mv_check_for_edma_empty_idle(struct ata_port *ap)
+{
+ void __iomem *port_mmio = mv_ap_base(ap);
+ const u32 empty_idle = (EDMA_STATUS_CACHE_EMPTY | EDMA_STATUS_IDLE);
+
+ u32 edma_stat = readl(port_mmio + EDMA_STATUS);
+ if ((edma_stat & empty_idle) == empty_idle)
+ return 0;
+ return ATA_DEFER_PORT;
+}
+
static int mv_qc_defer(struct ata_queued_cmd *qc)
{
struct ata_link *link = qc->dev->link;
@@ -1423,7 +1434,7 @@
* If the port is completely idle, then allow the new qc.
*/
if (ap->nr_active_links == 0)
- return 0;
+ return mv_check_for_edma_empty_idle(ap);
/*
* The port is operating in host queuing mode (EDMA) with NCQ
--- linux-3.4.4/drivers/ata/sata_mv.c 2012-06-22 14:37:50.000000000 -0400
+++ linux/drivers/ata/sata_mv.c 2012-08-07 14:14:43.554503157 -0400
@@ -1388,6 +1388,17 @@
}
}
+static int mv_check_for_edma_empty_idle(struct ata_port *ap)
+{
+ void __iomem *port_mmio = mv_ap_base(ap);
+ const u32 empty_idle = (EDMA_STATUS_CACHE_EMPTY | EDMA_STATUS_IDLE);
+
+ u32 edma_stat = readl(port_mmio + EDMA_STATUS);
+ if ((edma_stat & empty_idle) == empty_idle)
+ return 0;
+ return ATA_DEFER_PORT;
+}
+
static int mv_qc_defer(struct ata_queued_cmd *qc)
{
struct ata_link *link = qc->dev->link;
@@ -1423,7 +1434,7 @@
* If the port is completely idle, then allow the new qc.
*/
if (ap->nr_active_links == 0)
- return 0;
+ return mv_check_for_edma_empty_idle(ap);
/*
* The port is operating in host queuing mode (EDMA) with NCQ
