sata_mv: fix broken DSM/TRIM support (v2)

Fix DSM/TRIM commands in sata_mv (v2).
These need to be issued using old-school "BM DMA",
rather than via the EDMA host queue.

Since the chips don't have proper BM DMA status,
we need to be more careful with setting the ATA_DMA_INTR bit,
since DSM/TRIM often has a long delay between "DMA complete"
and "command complete".

GEN_I chips don't have BM DMA, so no TRIM for them.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Cc: stable@kernel.org

1 files changed, 37 insertions, 7 deletions

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 9463c71dd38e..81982594a014 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -1898,19 +1898,25 @@ static void mv_bmdma_start(struct ata_queued_cmd *qc)
  *      LOCKING:
  *      Inherited from caller.
  */
-static void mv_bmdma_stop(struct ata_queued_cmd *qc)
+static void mv_bmdma_stop_ap(struct ata_port *ap)
 {
-        struct ata_port *ap = qc->ap;
         void __iomem *port_mmio = mv_ap_base(ap);
         u32 cmd;
 
         /* clear start/stop bit */
         cmd = readl(port_mmio + BMDMA_CMD);
-        cmd &= ~ATA_DMA_START;
-        writelfl(cmd, port_mmio + BMDMA_CMD);
+        if (cmd & ATA_DMA_START) {
+                cmd &= ~ATA_DMA_START;
+                writelfl(cmd, port_mmio + BMDMA_CMD);
+
+                /* one-PIO-cycle guaranteed wait, per spec, for HDMA1:0 transition */
+                ata_sff_dma_pause(ap);
+        }
+}
 
-        /* one-PIO-cycle guaranteed wait, per spec, for HDMA1:0 transition */
-        ata_sff_dma_pause(ap);
+static void mv_bmdma_stop(struct ata_queued_cmd *qc)
+{
+        mv_bmdma_stop_ap(qc->ap);
 }
 
 /**
@@ -1934,8 +1940,21 @@ static u8 mv_bmdma_status(struct ata_port *ap)
         reg = readl(port_mmio + BMDMA_STATUS);
         if (reg & ATA_DMA_ACTIVE)
                 status = ATA_DMA_ACTIVE;
-        else
+        else if (reg & ATA_DMA_ERR)
                 status = (reg & ATA_DMA_ERR) | ATA_DMA_INTR;
+        else {
+                /*
+                 * Just because DMA_ACTIVE is 0 (DMA completed),
+                 * this does _not_ mean the device is "done".
+                 * So we should not yet be signalling ATA_DMA_INTR
+                 * in some cases.  Eg. DSM/TRIM, and perhaps others.
+                 */
+                mv_bmdma_stop_ap(ap);
+                if (ioread8(ap->ioaddr.altstatus_addr) & ATA_BUSY)
+                        status = 0;
+                else
+                        status = ATA_DMA_INTR;
+        }
         return status;
 }
 
@@ -1995,6 +2014,9 @@ static void mv_qc_prep(struct ata_queued_cmd *qc)
 
         switch (tf->protocol) {
         case ATA_PROT_DMA:
+                if (tf->command == ATA_CMD_DSM)
+                        return;
+                /* fall-thru */
         case ATA_PROT_NCQ:
                 break;  /* continue below */
         case ATA_PROT_PIO:
@@ -2094,6 +2116,8 @@ static void mv_qc_prep_iie(struct ata_queued_cmd *qc)
         if ((tf->protocol != ATA_PROT_DMA) &&
             (tf->protocol != ATA_PROT_NCQ))
                 return;
+        if (tf->command == ATA_CMD_DSM)
+                return;  /* use bmdma for this */
 
         /* Fill in Gen IIE command request block */
         if (!(tf->flags & ATA_TFLAG_WRITE))
@@ -2289,6 +2313,12 @@ static unsigned int mv_qc_issue(struct ata_queued_cmd *qc)
 
         switch (qc->tf.protocol) {
         case ATA_PROT_DMA:
+                if (qc->tf.command == ATA_CMD_DSM) {
+                        if (!ap->ops->bmdma_setup)  /* no bmdma on GEN_I */
+                                return AC_ERR_OTHER;
+                        break;  /* use bmdma for this */
+                }
+                /* fall thru */
         case ATA_PROT_NCQ:
                 mv_start_edma(ap, port_mmio, pp, qc->tf.protocol);
                 pp->req_idx = (pp->req_idx + 1) & MV_MAX_Q_DEPTH_MASK;