sata_mv pci features

Some of the GenIIe EDMA optimizations should not be used
for non-PCI (SOC) devices, and nor for certain configurations
of conventional PCI (non PCI-X, PCIe) buses.

Logic taken/simplified from that in the Marvell proprietary driver.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/sata_mv.c

@@ -361,6 +361,7 @@ enum {
 	MV_HP_GEN_II		= (1 << 7),	/* Generation II: 60xx */
 	MV_HP_GEN_IIE		= (1 << 8),	/* Generation IIE: 6042/7042 */
 	MV_HP_PCIE		= (1 << 9),	/* PCIe bus/regs: 7042 */
+	MV_HP_CUT_THROUGH	= (1 << 10),	/* can use EDMA cut-through */
 
 	/* Port private flags (pp_flags) */
 	MV_PP_FLAG_EDMA_EN	= (1 << 0),	/* is EDMA engine enabled? */
@@ -1110,8 +1111,10 @@ static void mv_edma_cfg(struct ata_port *ap, int want_ncq)
 	else if (IS_GEN_IIE(hpriv)) {
 		cfg |= (1 << 23);	/* do not mask PM field in rx'd FIS */
 		cfg |= (1 << 22);	/* enab 4-entry host queue cache */
-		cfg |= (1 << 18);	/* enab early completion */
-		cfg |= (1 << 17);	/* enab cut-through (dis stor&forwrd) */
+		if (HAS_PCI(ap->host))
+			cfg |= (1 << 18);	/* enab early completion */
+		if (hpriv->hp_flags & MV_HP_CUT_THROUGH)
+			cfg |= (1 << 17); /* enab cut-thru (dis stor&forwrd) */
 
 		if (want_ncq && sata_pmp_attached(ap)) {
 			cfg |= EDMA_CFG_EDMA_FBS; /* FIS-based switching */
@@ -2496,6 +2499,34 @@ static void mv_port_init(struct ata_ioports *port,  void __iomem *port_mmio)
 		readl(port_mmio + EDMA_ERR_IRQ_MASK_OFS));
 }
 
+static unsigned int mv_in_pcix_mode(struct ata_host *host)
+{
+	struct mv_host_priv *hpriv = host->private_data;
+	void __iomem *mmio = hpriv->base;
+	u32 reg;
+
+	if (!HAS_PCI(host) || !IS_PCIE(hpriv))
+		return 0;	/* not PCI-X capable */
+	reg = readl(mmio + MV_PCI_MODE_OFS);
+	if ((reg & MV_PCI_MODE_MASK) == 0)
+		return 0;	/* conventional PCI mode */
+	return 1;	/* chip is in PCI-X mode */
+}
+
+static int mv_pci_cut_through_okay(struct ata_host *host)
+{
+	struct mv_host_priv *hpriv = host->private_data;
+	void __iomem *mmio = hpriv->base;
+	u32 reg;
+
+	if (!mv_in_pcix_mode(host)) {
+		reg = readl(mmio + PCI_COMMAND_OFS);
+		if (reg & PCI_COMMAND_MRDTRIG)
+			return 0; /* not okay */
+	}
+	return 1; /* okay */
+}
+
 static int mv_chip_id(struct ata_host *host, unsigned int board_idx)
 {
 	struct pci_dev *pdev = to_pci_dev(host->dev);
@@ -2563,7 +2594,7 @@ static int mv_chip_id(struct ata_host *host, unsigned int board_idx)
 		break;
 
 	case chip_7042:
-		hp_flags |= MV_HP_PCIE;
+		hp_flags |= MV_HP_PCIE | MV_HP_CUT_THROUGH;
 		if (pdev->vendor == PCI_VENDOR_ID_TTI &&
 		    (pdev->device == 0x2300 || pdev->device == 0x2310))
 		{
@@ -2597,6 +2628,8 @@ static int mv_chip_id(struct ata_host *host, unsigned int board_idx)
 	case chip_6042:
 		hpriv->ops = &mv6xxx_ops;
 		hp_flags |= MV_HP_GEN_IIE;
+		if (board_idx == chip_6042 && mv_pci_cut_through_okay(host))
+			hp_flags |= MV_HP_CUT_THROUGH;
 
 		switch (pdev->revision) {
 		case 0x0: