sata_mv clean up mv_stop_edma usage

Clean up uses of mv_stop_edma{_engine}() to match datasheet requirements.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 42 insertions, 45 deletions

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index ee6ca97c4545..5b9f937d0f87 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -517,7 +517,7 @@ static void mv_reset_pci_bus(struct ata_host *host, void __iomem *mmio);
 static void mv_reset_channel(struct mv_host_priv *hpriv, void __iomem *mmio,
                              unsigned int port_no);
 static int mv_stop_edma(struct ata_port *ap);
-static int mv_stop_edma_engine(struct ata_port *ap);
+static int mv_stop_edma_engine(void __iomem *port_mmio);
 static void mv_edma_cfg(struct ata_port *ap, int want_ncq);
 
 /* .sg_tablesize is (MV_MAX_SG_CT / 2) in the structures below
@@ -805,7 +805,7 @@ static void mv_start_dma(struct ata_port *ap, void __iomem *port_mmio,
         if (pp->pp_flags & MV_PP_FLAG_EDMA_EN) {
                 int using_ncq = ((pp->pp_flags & MV_PP_FLAG_NCQ_EN) != 0);
                 if (want_ncq != using_ncq)
-                        mv_stop_edma_engine(ap);
+                        mv_stop_edma(ap);
         }
         if (!(pp->pp_flags & MV_PP_FLAG_EDMA_EN)) {
                 struct mv_host_priv *hpriv = ap->host->private_data;
@@ -841,57 +841,41 @@ static void mv_start_dma(struct ata_port *ap, void __iomem *port_mmio,
 
 /**
  *      mv_stop_edma_engine - Disable eDMA engine
- *      @ap: ATA channel to manipulate
- *
- *      Verify the local cache of the eDMA state is accurate with a
- *      WARN_ON.
+ *      @port_mmio: io base address
  *
  *      LOCKING:
  *      Inherited from caller.
  */
-static int mv_stop_edma_engine(struct ata_port *ap)
+static int mv_stop_edma_engine(void __iomem *port_mmio)
 {
-        void __iomem *port_mmio = mv_ap_base(ap);
-        struct mv_port_priv *pp = ap->private_data;
-        u32 reg;
-        int i, err = 0;
+        int i;
 
-        if (pp->pp_flags & MV_PP_FLAG_EDMA_EN) {
-                /* Disable EDMA if active.   The disable bit auto clears.
-                 */
-                writelfl(EDMA_DS, port_mmio + EDMA_CMD_OFS);
-                pp->pp_flags &= ~MV_PP_FLAG_EDMA_EN;
-        } else {
-                WARN_ON(EDMA_EN & readl(port_mmio + EDMA_CMD_OFS));
-        }
+        /* Disable eDMA.  The disable bit auto clears. */
+        writelfl(EDMA_DS, port_mmio + EDMA_CMD_OFS);
 
-        /* now properly wait for the eDMA to stop */
-        for (i = 1000; i > 0; i--) {
-                reg = readl(port_mmio + EDMA_CMD_OFS);
+        /* Wait for the chip to confirm eDMA is off. */
+        for (i = 10000; i > 0; i--) {
+                u32 reg = readl(port_mmio + EDMA_CMD_OFS);
                 if (!(reg & EDMA_EN))
-                        break;
-
-                udelay(100);
-        }
-
-        if (reg & EDMA_EN) {
-                ata_port_printk(ap, KERN_ERR, "Unable to stop eDMA\n");
-                err = -EIO;
+                        return 0;
+                udelay(10);
         }
-
-        return err;
+        return -EIO;
 }
 
 static int mv_stop_edma(struct ata_port *ap)
 {
-        unsigned long flags;
-        int rc;
-
-        spin_lock_irqsave(&ap->host->lock, flags);
-        rc = mv_stop_edma_engine(ap);
-        spin_unlock_irqrestore(&ap->host->lock, flags);
+        void __iomem *port_mmio = mv_ap_base(ap);
+        struct mv_port_priv *pp = ap->private_data;
 
-        return rc;
+        if (!(pp->pp_flags & MV_PP_FLAG_EDMA_EN))
+                return 0;
+        pp->pp_flags &= ~MV_PP_FLAG_EDMA_EN;
+        if (mv_stop_edma_engine(port_mmio)) {
+                ata_port_printk(ap, KERN_ERR, "Unable to stop eDMA\n");
+                return -EIO;
+        }
+        return 0;
 }
 
 #ifdef ATA_DEBUG
@@ -1401,7 +1385,7 @@ static unsigned int mv_qc_issue(struct ata_queued_cmd *qc)
                  * port.  Turn off EDMA so there won't be problems accessing
                  * shadow block, etc registers.
                  */
-                mv_stop_edma_engine(ap);
+                mv_stop_edma(ap);
                 return ata_qc_issue_prot(qc);
         }
 
@@ -1915,8 +1899,12 @@ static void mv5_reset_hc_port(struct mv_host_priv *hpriv, void __iomem *mmio,
 {
         void __iomem *port_mmio = mv_port_base(mmio, port);
 
-        writelfl(EDMA_DS, port_mmio + EDMA_CMD_OFS);
-
+        /*
+         * The datasheet warns against setting ATA_RST when EDMA is active
+         * (but doesn't say what the problem might be).  So we first try
+         * to disable the EDMA engine before doing the ATA_RST operation.
+         */
+        mv_stop_edma_engine(port_mmio);
         mv_reset_channel(hpriv, mmio, port);
 
         ZERO(0x028);    /* command */
@@ -2191,8 +2179,12 @@ static void mv_soc_reset_hc_port(struct mv_host_priv *hpriv,
 {
         void __iomem *port_mmio = mv_port_base(mmio, port);
 
-        writelfl(EDMA_DS, port_mmio + EDMA_CMD_OFS);
-
+        /*
+         * The datasheet warns against setting ATA_RST when EDMA is active
+         * (but doesn't say what the problem might be).  So we first try
+         * to disable the EDMA engine before doing the ATA_RST operation.
+         */
+        mv_stop_edma_engine(port_mmio);
         mv_reset_channel(hpriv, mmio, port);
 
         ZERO(0x028);            /* command */
@@ -2250,6 +2242,10 @@ static void mv_soc_reset_bus(struct ata_host *host, void __iomem *mmio)
         return;
 }
 
+/*
+ * Caller must ensure that EDMA is not active,
+ * by first doing mv_stop_edma() where needed.
+ */
 static void mv_reset_channel(struct mv_host_priv *hpriv, void __iomem *mmio,
                              unsigned int port_no)
 {
@@ -2392,10 +2388,11 @@ static int mv_hardreset(struct ata_link *link, unsigned int *class,
 {
         struct ata_port *ap = link->ap;
         struct mv_host_priv *hpriv = ap->host->private_data;
+        struct mv_port_priv *pp = ap->private_data;
         void __iomem *mmio = hpriv->base;
 
-        mv_stop_edma(ap);
         mv_reset_channel(hpriv, mmio, ap->port_no);
+        pp->pp_flags &= ~MV_PP_FLAG_EDMA_EN;
         mv_phy_reset(ap, class, deadline);
 
         return 0;