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[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>
This commit is contained in:
Mark Lord 2009-02-25 15:14:48 -05:00 committed by Jeff Garzik
parent 08da175937
commit c01e8a2312
1 changed files with 28 additions and 24 deletions
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52
drivers/ata/sata_mv.c
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@ -345,7 +345,7 @@ enum {
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 @@ struct mv_cached_regs {
u32 fiscfg;
u32 ltmode;
u32 haltcond;
u32 unknown_rsvd;
};
struct mv_port_priv {
@ -563,8 +564,6 @@ static void mv_pmp_error_handler(struct ata_port *ap);
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 @@ static struct ata_port_operations mv6_ops = {
.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 @@ static void mv_save_cached_regs(struct ata_port *ap)
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 @@ static void mv_60x1_errata_sata25(struct ata_port *ap, int want_ncq)
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 @@ static void mv_edma_cfg(struct ata_port *ap, int want_ncq, int want_edma)
}
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) {
@ -1464,26 +1488,6 @@ static void mv_crqb_pack_cmd(__le16 *cmdw, u8 data, u8 addr, unsigned last)
*cmdw = cpu_to_le16(tmp);
}
/**
* 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.