Part five of simplifying/fixing handling of the main_irq_mask register
to resolve unexpected interrupt issues observed in 2.6.26-rc*.
Keep a cached copy of the main_irq_mask so that we don't have
to stall the CPU to read it on every pass through mv_interrupt.
This significantly speeds up interrupt handling, both for sata_mv,
and for any other driver/device sharing the same PCI IRQ line.
Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
--- old/drivers/ata/sata_mv.c 2008-05-16 16:06:23.000000000 -0400
+++ linux/drivers/ata/sata_mv.c 2008-05-16 16:02:55.000000000 -0400
@@ -458,6 +458,7 @@
struct mv_host_priv {
u32 hp_flags;
+ u32 main_irq_mask;
struct mv_port_signal signal[8];
const struct mv_hw_ops *ops;
int n_ports;
@@ -843,10 +844,12 @@
struct mv_host_priv *hpriv = host->private_data;
u32 old_mask, new_mask;
- old_mask = readl(hpriv->main_irq_mask_addr);
+ old_mask = hpriv->main_irq_mask;
new_mask = (old_mask & ~disable_bits) | enable_bits;
- if (new_mask != old_mask)
+ if (new_mask != old_mask) {
+ hpriv->main_irq_mask = new_mask;
writelfl(new_mask, hpriv->main_irq_mask_addr);
+ }
}
static void mv_enable_port_irqs(struct ata_port *ap,
@@ -2200,12 +2203,11 @@
struct ata_host *host = dev_instance;
struct mv_host_priv *hpriv = host->private_data;
unsigned int handled = 0;
- u32 main_irq_cause, main_irq_mask, pending_irqs;
+ u32 main_irq_cause, pending_irqs;
spin_lock(&host->lock);
main_irq_cause = readl(hpriv->main_irq_cause_addr);
- main_irq_mask = readl(hpriv->main_irq_mask_addr);
- pending_irqs = main_irq_cause & main_irq_mask;
+ pending_irqs = main_irq_cause & hpriv->main_irq_mask;
/*
* Deal with cases where we either have nothing pending, or have read
* a bogus register value which can indicate HW removal or PCI fault.
--
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