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[libata] sata_mv: cache frequently-accessed registers 

Maintain a local (mv_port_priv) cache of frequently accessed registers,
to avoid having to re-read them (very slow) on every transistion
between EDMA and non-EDMA modes.  This speeds up things like
flushing the drive write cache, and anything using basic DMA transfers.

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 15:13:03 -05:00 committed by Jeff Garzik
parent a5bfc4714b
commit 08da175937
1 changed files with 70 additions and 21 deletions
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91
drivers/ata/sata_mv.c
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@ -438,6 +438,17 @@ struct mv_sg {
__le32 reserved;
};
/*
* We keep a local cache of a few frequently accessed port
* registers here, to avoid having to read them (very slow)
* when switching between EDMA and non-EDMA modes.
*/
struct mv_cached_regs {
u32 fiscfg;
u32 ltmode;
u32 haltcond;
};
struct mv_port_priv {
struct mv_crqb *crqb;
dma_addr_t crqb_dma;
@ -450,6 +461,7 @@ struct mv_port_priv {
unsigned int resp_idx;
u32 pp_flags;
struct mv_cached_regs cached;
unsigned int delayed_eh_pmp_map;
};
@ -812,6 +824,43 @@ static inline int mv_get_hc_count(unsigned long port_flags)
return ((port_flags & MV_FLAG_DUAL_HC) ? 2 : 1);
}
/**
* mv_save_cached_regs - (re-)initialize cached port registers
* @ap: the port whose registers we are caching
*
* Initialize the local cache of port registers,
* so that reading them over and over again can
* be avoided on the hotter paths of this driver.
* This saves a few microseconds each time we switch
* to/from EDMA mode to perform (eg.) a drive cache flush.
*/
static void mv_save_cached_regs(struct ata_port *ap)
{
void __iomem *port_mmio = mv_ap_base(ap);
struct mv_port_priv *pp = ap->private_data;
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);
}
/**
* mv_write_cached_reg - write to a cached port register
* @addr: hardware address of the register
* @old: pointer to cached value of the register
* @new: new value for the register
*
* Write a new value to a cached register,
* but only if the value is different from before.
*/
static inline void mv_write_cached_reg(void __iomem *addr, u32 *old, u32 new)
{
if (new != *old) {
*old = new;
writel(new, addr);
}
}
static void mv_set_edma_ptrs(void __iomem *port_mmio,
struct mv_host_priv *hpriv,
struct mv_port_priv *pp)
@ -1159,35 +1208,33 @@ static int mv_qc_defer(struct ata_queued_cmd *qc)
return ATA_DEFER_PORT;
}
static void mv_config_fbs(void __iomem *port_mmio, int want_ncq, int want_fbs)
static void mv_config_fbs(struct ata_port *ap, int want_ncq, int want_fbs)
{
u32 new_fiscfg, old_fiscfg;
u32 new_ltmode, old_ltmode;
u32 new_haltcond, old_haltcond;
struct mv_port_priv *pp = ap->private_data;
void __iomem *port_mmio;
old_fiscfg = readl(port_mmio + FISCFG_OFS);
old_ltmode = readl(port_mmio + LTMODE_OFS);
old_haltcond = readl(port_mmio + EDMA_HALTCOND_OFS);
u32 fiscfg, *old_fiscfg = &pp->cached.fiscfg;
u32 ltmode, *old_ltmode = &pp->cached.ltmode;
u32 haltcond, *old_haltcond = &pp->cached.haltcond;
new_fiscfg = old_fiscfg & ~(FISCFG_SINGLE_SYNC | FISCFG_WAIT_DEV_ERR);
new_ltmode = old_ltmode & ~LTMODE_BIT8;
new_haltcond = old_haltcond | EDMA_ERR_DEV;
ltmode = *old_ltmode & ~LTMODE_BIT8;
haltcond = *old_haltcond | EDMA_ERR_DEV;
if (want_fbs) {
new_fiscfg = old_fiscfg | FISCFG_SINGLE_SYNC;
new_ltmode = old_ltmode | LTMODE_BIT8;
fiscfg = *old_fiscfg | FISCFG_SINGLE_SYNC;
ltmode = *old_ltmode | LTMODE_BIT8;
if (want_ncq)
new_haltcond &= ~EDMA_ERR_DEV;
haltcond &= ~EDMA_ERR_DEV;
else
new_fiscfg |= FISCFG_WAIT_DEV_ERR;
fiscfg |= FISCFG_WAIT_DEV_ERR;
} else {
fiscfg = *old_fiscfg & ~(FISCFG_SINGLE_SYNC | FISCFG_WAIT_DEV_ERR);
}
if (new_fiscfg != old_fiscfg)
writelfl(new_fiscfg, port_mmio + FISCFG_OFS);
if (new_ltmode != old_ltmode)
writelfl(new_ltmode, port_mmio + LTMODE_OFS);
if (new_haltcond != old_haltcond)
writelfl(new_haltcond, port_mmio + EDMA_HALTCOND_OFS);
port_mmio = mv_ap_base(ap);
mv_write_cached_reg(port_mmio + FISCFG_OFS, old_fiscfg, fiscfg);
mv_write_cached_reg(port_mmio + LTMODE_OFS, old_ltmode, ltmode);
mv_write_cached_reg(port_mmio + EDMA_HALTCOND_OFS, old_haltcond, haltcond);
}
static void mv_60x1_errata_sata25(struct ata_port *ap, int want_ncq)
@ -1235,7 +1282,7 @@ static void mv_edma_cfg(struct ata_port *ap, int want_ncq, int want_edma)
*/
want_fbs &= want_ncq;
mv_config_fbs(port_mmio, want_ncq, want_fbs);
mv_config_fbs(ap, want_ncq, want_fbs);
if (want_fbs) {
pp->pp_flags |= MV_PP_FLAG_FBS_EN;
@ -1339,6 +1386,7 @@ static int mv_port_start(struct ata_port *ap)
pp->sg_tbl_dma[tag] = pp->sg_tbl_dma[0];
}
}
mv_save_cached_regs(ap);
mv_edma_cfg(ap, 0, 0);
return 0;
@ -2997,6 +3045,7 @@ static int mv_hardreset(struct ata_link *link, unsigned int *class,
extra = HZ; /* only extend it once, max */
}
} while (sstatus != 0x0 && sstatus != 0x113 && sstatus != 0x123);
mv_save_cached_regs(ap);
mv_edma_cfg(ap, 0, 0);
return rc;