[libata] sata_mv: don't touch reserved bits in EDMA config register

The code in mv_edma_cfg() reflected its 60xx origins, by doing things
[slightly] incorrectly on the older 50xx and newer 6042/7042 chips.

Clean up the EDMA configuration setup such that, each chip family
carefully initializes its own EDMA setup.

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 12 insertions, 8 deletions

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index d724bc799b1a..cc59aca12d42 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -814,23 +814,27 @@ static void mv_edma_cfg(struct mv_host_priv *hpriv, void __iomem *port_mmio)
         u32 cfg = readl(port_mmio + EDMA_CFG_OFS);
 
         /* set up non-NCQ EDMA configuration */
-        cfg &= ~0x1f;           /* clear queue depth */
-        cfg &= ~EDMA_CFG_NCQ;   /* clear NCQ mode */
         cfg &= ~(1 << 9);       /* disable equeue */
 
-        if (IS_GEN_I(hpriv))
+        if (IS_GEN_I(hpriv)) {
+                cfg &= ~0x1f;           /* clear queue depth */
                 cfg |= (1 << 8);        /* enab config burst size mask */
+        }
 
-        else if (IS_GEN_II(hpriv))
+        else if (IS_GEN_II(hpriv)) {
+                cfg &= ~0x1f;           /* clear queue depth */
                 cfg |= EDMA_CFG_RD_BRST_EXT | EDMA_CFG_WR_BUFF_LEN;
+                cfg &= ~(EDMA_CFG_NCQ | EDMA_CFG_NCQ_GO_ON_ERR); /* clear NCQ */
+        }
 
         else if (IS_GEN_IIE(hpriv)) {
-                cfg |= (1 << 23);       /* dis RX PM port mask */
-                cfg &= ~(1 << 16);      /* dis FIS-based switching (for now) */
+                cfg |= (1 << 23);       /* do not mask PM field in rx'd FIS */
+                cfg |= (1 << 22);       /* enab 4-entry host queue cache */
                 cfg &= ~(1 << 19);      /* dis 128-entry queue (for now?) */
                 cfg |= (1 << 18);       /* enab early completion */
-                cfg |= (1 << 17);       /* enab host q cache */
-                cfg |= (1 << 22);       /* enab cutthrough */
+                cfg |= (1 << 17);       /* enab cut-through (dis stor&forwrd) */
+                cfg &= ~(1 << 16);      /* dis FIS-based switching (for now) */
+                cfg &= ~(EDMA_CFG_NCQ | EDMA_CFG_NCQ_GO_ON_ERR); /* clear NCQ */
         }
 
         writelfl(cfg, port_mmio + EDMA_CFG_OFS);