[libata] sata_mv: Enable use of (basic) DMA for ATAPI on GEN_IIE chips
This also gets rid of any need for mv_mode_filter().
Using basic DMA on GEN_IIE requires setting an undocumented
bit in an undocumented register. For safety, we clear that
bit again when switching back to EDMA mode.
To avoid a performance penalty when switching modes,
we cache the register in port_priv, as already done for other regs.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 146b8e6..3bfe721 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -345,7 +345,7 @@
EDMA_ARB_CFG_OFS = 0x38,
EDMA_HALTCOND_OFS = 0x60, /* GenIIe halt conditions */
-
+ EDMA_UNKNOWN_RSVD_OFS = 0x6C, /* GenIIe unknown/reserved */
BMDMA_CMD_OFS = 0x224, /* bmdma command register */
BMDMA_STATUS_OFS = 0x228, /* bmdma status register */
@@ -447,6 +447,7 @@
u32 fiscfg;
u32 ltmode;
u32 haltcond;
+ u32 unknown_rsvd;
};
struct mv_port_priv {
@@ -563,8 +564,6 @@
static void mv_process_crpb_entries(struct ata_port *ap,
struct mv_port_priv *pp);
-static unsigned long mv_mode_filter(struct ata_device *dev,
- unsigned long xfer_mask);
static void mv_sff_irq_clear(struct ata_port *ap);
static int mv_check_atapi_dma(struct ata_queued_cmd *qc);
static void mv_bmdma_setup(struct ata_queued_cmd *qc);
@@ -626,7 +625,6 @@
.bmdma_start = mv_bmdma_start,
.bmdma_stop = mv_bmdma_stop,
.bmdma_status = mv_bmdma_status,
- .mode_filter = mv_mode_filter,
};
static struct ata_port_operations mv_iie_ops = {
@@ -842,6 +840,7 @@
pp->cached.fiscfg = readl(port_mmio + FISCFG_OFS);
pp->cached.ltmode = readl(port_mmio + LTMODE_OFS);
pp->cached.haltcond = readl(port_mmio + EDMA_HALTCOND_OFS);
+ pp->cached.unknown_rsvd = readl(port_mmio + EDMA_UNKNOWN_RSVD_OFS);
}
/**
@@ -1252,6 +1251,30 @@
writel(new, hpriv->base + MV_GPIO_PORT_CTL_OFS);
}
+/**
+ * mv_bmdma_enable - set a magic bit on GEN_IIE to allow bmdma
+ * @ap: Port being initialized
+ *
+ * There are two DMA modes on these chips: basic DMA, and EDMA.
+ *
+ * Bit-0 of the "EDMA RESERVED" register enables/disables use
+ * of basic DMA on the GEN_IIE versions of the chips.
+ *
+ * This bit survives EDMA resets, and must be set for basic DMA
+ * to function, and should be cleared when EDMA is active.
+ */
+static void mv_bmdma_enable_iie(struct ata_port *ap, int enable_bmdma)
+{
+ struct mv_port_priv *pp = ap->private_data;
+ u32 new, *old = &pp->cached.unknown_rsvd;
+
+ if (enable_bmdma)
+ new = *old | 1;
+ else
+ new = *old & ~1;
+ mv_write_cached_reg(mv_ap_base(ap) + EDMA_UNKNOWN_RSVD_OFS, old, new);
+}
+
static void mv_edma_cfg(struct ata_port *ap, int want_ncq, int want_edma)
{
u32 cfg;
@@ -1297,6 +1320,7 @@
}
if (hpriv->hp_flags & MV_HP_CUT_THROUGH)
cfg |= (1 << 17); /* enab cut-thru (dis stor&forwrd) */
+ mv_bmdma_enable_iie(ap, !want_edma);
}
if (want_ncq) {
@@ -1465,26 +1489,6 @@
}
/**
- * mv_mode_filter - Allow ATAPI DMA only on GenII chips.
- * @dev: device whose xfer modes are being configured.
- *
- * Only the GenII hardware can use DMA with ATAPI drives.
- */
-static unsigned long mv_mode_filter(struct ata_device *adev,
- unsigned long xfer_mask)
-{
- if (adev->class == ATA_DEV_ATAPI) {
- struct mv_host_priv *hpriv = adev->link->ap->host->private_data;
- if (!IS_GEN_II(hpriv)) {
- xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
- ata_dev_printk(adev, KERN_INFO,
- "ATAPI DMA not supported on this chipset\n");
- }
- }
- return xfer_mask;
-}
-
-/**
* mv_sff_irq_clear - Clear hardware interrupt after DMA.
* @ap: Port associated with this ATA transaction.
*