[libata] sata_mv: minor cleanups

* trim trailing whitespace
* document some flags, registers, and register bits
* fix locking around EDMA on/off and configuration
* continue replacing "constant OP var" with "var OP constant"
* use new pci_try_set_mwi()

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

1 files changed, 38 insertions, 24 deletions

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 0ccd990c8dac..80ade5b93b86 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -35,8 +35,6 @@
 
   6) Add port multiplier support (intermediate)
 
-  7) Test and verify 3.0 Gbps support
-
   8) Develop a low-power-consumption strategy, and implement it.
 
   9) [Experiment, low priority] See if ATAPI can be supported using
@@ -286,10 +284,10 @@ enum {
         EDMA_RSP_Q_OUT_PTR_OFS  = 0x24,         /* also contains BASE_LO */
         EDMA_RSP_Q_PTR_SHIFT    = 3,
 
-        EDMA_CMD_OFS            = 0x28,
-        EDMA_EN                 = (1 << 0),
-        EDMA_DS                 = (1 << 1),
-        ATA_RST                 = (1 << 2),
+        EDMA_CMD_OFS            = 0x28,         /* EDMA command register */
+        EDMA_EN                 = (1 << 0),     /* enable EDMA */
+        EDMA_DS                 = (1 << 1),     /* disable EDMA; self-negated */
+        ATA_RST                 = (1 << 2),     /* reset trans/link/phy */
 
         EDMA_IORDY_TMOUT        = 0x34,
         EDMA_ARB_CFG            = 0x38,
@@ -301,14 +299,13 @@ enum {
         MV_HP_ERRATA_60X1B2     = (1 << 3),
         MV_HP_ERRATA_60X1C0     = (1 << 4),
         MV_HP_ERRATA_XX42A0     = (1 << 5),
-        MV_HP_GEN_I             = (1 << 6),
-        MV_HP_GEN_II            = (1 << 7),
-        MV_HP_GEN_IIE           = (1 << 8),
+        MV_HP_GEN_I             = (1 << 6),     /* Generation I: 50xx */
+        MV_HP_GEN_II            = (1 << 7),     /* Generation II: 60xx */
+        MV_HP_GEN_IIE           = (1 << 8),     /* Generation IIE: 6042/7042 */
 
         /* Port private flags (pp_flags) */
-        MV_PP_FLAG_EDMA_EN      = (1 << 0),
-        MV_PP_FLAG_EDMA_DS_ACT  = (1 << 1),
-        MV_PP_FLAG_HAD_A_RESET  = (1 << 2),
+        MV_PP_FLAG_EDMA_EN      = (1 << 0),     /* is EDMA engine enabled? */
+        MV_PP_FLAG_HAD_A_RESET  = (1 << 2),     /* 1st hard reset complete? */
 };
 
 #define IS_GEN_I(hpriv) ((hpriv)->hp_flags & MV_HP_GEN_I)
@@ -318,8 +315,12 @@ enum {
 enum {
         MV_DMA_BOUNDARY         = 0xffffffffU,
 
+        /* mask of register bits containing lower 32 bits
+         * of EDMA request queue DMA address
+         */
         EDMA_REQ_Q_BASE_LO_MASK = 0xfffffc00U,
 
+        /* ditto, for response queue */
         EDMA_RSP_Q_BASE_LO_MASK = 0xffffff00U,
 };
 
@@ -823,7 +824,7 @@ static void mv_start_dma(void __iomem *base, struct mv_host_priv *hpriv,
 }
 
 /**
- *      mv_stop_dma - Disable eDMA engine
+ *      __mv_stop_dma - Disable eDMA engine
  *      @ap: ATA channel to manipulate
  *
  *      Verify the local cache of the eDMA state is accurate with a
@@ -832,7 +833,7 @@ static void mv_start_dma(void __iomem *base, struct mv_host_priv *hpriv,
  *      LOCKING:
  *      Inherited from caller.
  */
-static int mv_stop_dma(struct ata_port *ap)
+static int __mv_stop_dma(struct ata_port *ap)
 {
         void __iomem *port_mmio = mv_ap_base(ap);
         struct mv_port_priv *pp = ap->private_data;
@@ -865,6 +866,18 @@ static int mv_stop_dma(struct ata_port *ap)
         return err;
 }
 
+static int mv_stop_dma(struct ata_port *ap)
+{
+        unsigned long flags;
+        int rc;
+
+        spin_lock_irqsave(&ap->host->lock, flags);
+        rc = __mv_stop_dma(ap);
+        spin_unlock_irqrestore(&ap->host->lock, flags);
+
+        return rc;
+}
+
 #ifdef ATA_DEBUG
 static void mv_dump_mem(void __iomem *start, unsigned bytes)
 {
@@ -965,7 +978,7 @@ static u32 mv_scr_read(struct ata_port *ap, unsigned int sc_reg_in)
 {
         unsigned int ofs = mv_scr_offset(sc_reg_in);
 
-        if (0xffffffffU != ofs)
+        if (ofs != 0xffffffffU)
                 return readl(mv_ap_base(ap) + ofs);
         else
                 return (u32) ofs;
@@ -975,7 +988,7 @@ static void mv_scr_write(struct ata_port *ap, unsigned int sc_reg_in, u32 val)
 {
         unsigned int ofs = mv_scr_offset(sc_reg_in);
 
-        if (0xffffffffU != ofs)
+        if (ofs != 0xffffffffU)
                 writelfl(val, mv_ap_base(ap) + ofs);
 }
 
@@ -1029,6 +1042,7 @@ static int mv_port_start(struct ata_port *ap)
         void __iomem *port_mmio = mv_ap_base(ap);
         void *mem;
         dma_addr_t mem_dma;
+        unsigned long flags;
         int rc;
 
         pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL);
@@ -1067,10 +1081,14 @@ static int mv_port_start(struct ata_port *ap)
         pp->sg_tbl = mem;
         pp->sg_tbl_dma = mem_dma;
 
+        spin_lock_irqsave(&ap->host->lock, flags);
+
         mv_edma_cfg(ap, hpriv, port_mmio);
 
         mv_set_edma_ptrs(port_mmio, hpriv, pp);
 
+        spin_unlock_irqrestore(&ap->host->lock, flags);
+
         /* Don't turn on EDMA here...do it before DMA commands only.  Else
          * we'll be unable to send non-data, PIO, etc due to restricted access
          * to shadow regs.
@@ -1090,11 +1108,7 @@ static int mv_port_start(struct ata_port *ap)
  */
 static void mv_port_stop(struct ata_port *ap)
 {
-        unsigned long flags;
-
-        spin_lock_irqsave(&ap->host->lock, flags);
         mv_stop_dma(ap);
-        spin_unlock_irqrestore(&ap->host->lock, flags);
 }
 
 /**
@@ -1325,7 +1339,7 @@ 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_dma(ap);
+                __mv_stop_dma(ap);
                 return ata_qc_issue_prot(qc);
         }
 
@@ -1497,7 +1511,7 @@ static void mv_intr_edma(struct ata_port *ap)
                         break;
 
                 /* 50xx: get active ATA command */
-                if (IS_GEN_I(hpriv)) 
+                if (IS_GEN_I(hpriv))
                         tag = ap->active_tag;
 
                 /* Gen II/IIE: get active ATA command via tag, to enable
@@ -1532,7 +1546,7 @@ static void mv_intr_edma(struct ata_port *ap)
                         ata_qc_complete(qc);
                 }
 
-                /* advance software response queue pointer, to 
+                /* advance software response queue pointer, to
                  * indicate (after the loop completes) to hardware
                  * that we have consumed a response queue entry.
                  */
@@ -2206,7 +2220,7 @@ static int mv_prereset(struct ata_port *ap, unsigned long deadline)
         struct mv_port_priv *pp = ap->private_data;
         struct ata_eh_context *ehc = &ap->eh_context;
         int rc;
-        
+
         rc = mv_stop_dma(ap);
         if (rc)
                 ehc->i.action |= ATA_EH_HARDRESET;