diff options
| author | Mark Lord <liml@rtr.ca> | 2009-01-19 18:05:42 -0500 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@redhat.com> | 2009-01-26 06:36:53 -0500 |
| commit | cae6edc3b5a536119374a5439d9b253cb26f05e1 (patch) | |
| tree | 14c8706bb6a6a8135b12b66623e005df825b454f /drivers | |
| parent | b0bccb18bc523d1d5060d25958f12438062829a9 (diff) | |
| download | kernel_samsung_espresso10-cae6edc3b5a536119374a5439d9b253cb26f05e1.zip kernel_samsung_espresso10-cae6edc3b5a536119374a5439d9b253cb26f05e1.tar.gz kernel_samsung_espresso10-cae6edc3b5a536119374a5439d9b253cb26f05e1.tar.bz2 | |
sata_mv: don't read hc_irq_cause
Remove silly read-modify-write sequences when clearing interrupts
in hc_irq_cause. This gets rid of unneeded MMIO reads, resulting in
a slight performance boost when switching between EDMA and non-EDMA
modes (eg. for cache flushes).
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/ata/sata_mv.c | 17 |
1 files changed, 5 insertions, 12 deletions
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c index ce9d6ad..6809628 100644 --- a/drivers/ata/sata_mv.c +++ b/drivers/ata/sata_mv.c @@ -35,8 +35,6 @@ * * --> Investigate problems with PCI Message Signalled Interrupts (MSI). * - * --> Cache frequently-accessed registers in mv_port_priv to reduce overhead. - * * --> Develop a low-power-consumption strategy, and implement it. * * --> [Experiment, low priority] Investigate interrupt coalescing. @@ -884,18 +882,14 @@ static void mv_start_dma(struct ata_port *ap, void __iomem *port_mmio, int hardport = mv_hardport_from_port(ap->port_no); void __iomem *hc_mmio = mv_hc_base_from_port( mv_host_base(ap->host), ap->port_no); - u32 hc_irq_cause, ipending; + u32 hc_irq_cause; /* clear EDMA event indicators, if any */ writelfl(0, port_mmio + EDMA_ERR_IRQ_CAUSE_OFS); - /* clear EDMA interrupt indicator, if any */ - hc_irq_cause = readl(hc_mmio + HC_IRQ_CAUSE_OFS); - ipending = (DEV_IRQ | DMA_IRQ) << hardport; - if (hc_irq_cause & ipending) { - writelfl(hc_irq_cause & ~ipending, - hc_mmio + HC_IRQ_CAUSE_OFS); - } + /* clear pending irq events */ + hc_irq_cause = ~((DEV_IRQ | DMA_IRQ) << hardport); + writelfl(hc_irq_cause, hc_mmio + HC_IRQ_CAUSE_OFS); mv_edma_cfg(ap, want_ncq); @@ -2821,8 +2815,7 @@ static void mv_eh_thaw(struct ata_port *ap) writel(0, port_mmio + EDMA_ERR_IRQ_CAUSE_OFS); /* clear pending irq events */ - hc_irq_cause = readl(hc_mmio + HC_IRQ_CAUSE_OFS); - hc_irq_cause &= ~((DEV_IRQ | DMA_IRQ) << hardport); + hc_irq_cause = ~((DEV_IRQ | DMA_IRQ) << hardport); writelfl(hc_irq_cause, hc_mmio + HC_IRQ_CAUSE_OFS); mv_enable_port_irqs(ap, ERR_IRQ); |