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[POWERPC] qe_ic: Do a sync when masking interrupts 

This patch causes a sync do be done after masking a QE interrupt, to
ensure that the masking has completed before interrupts are enabled.
This allows the masking of the cascade IRQ to be removed without causing
spurious interrupts.

The mask_and_ack function is also removed and set to the mask function,
as the two are identical.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Scott Wood 2006-12-06 15:16:24 -06:00 committed by Paul Mackerras
parent d0e70341c0
commit 2c1d2f34a0
1 changed files with 10 additions and 30 deletions
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40
arch/powerpc/sysdev/qe_lib/qe_ic.c
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@ -223,23 +223,15 @@ static void qe_ic_mask_irq(unsigned int virq)
qe_ic_write(qe_ic->regs, qe_ic_info[src].mask_reg,
temp & ~qe_ic_info[src].mask);
spin_unlock_irqrestore(&qe_ic_lock, flags);
}
static void qe_ic_mask_irq_and_ack(unsigned int virq)
{
struct qe_ic *qe_ic = qe_ic_from_irq(virq);
unsigned int src = virq_to_hw(virq);
unsigned long flags;
u32 temp;
spin_lock_irqsave(&qe_ic_lock, flags);
temp = qe_ic_read(qe_ic->regs, qe_ic_info[src].mask_reg);
qe_ic_write(qe_ic->regs, qe_ic_info[src].mask_reg,
temp & ~qe_ic_info[src].mask);
/* There is nothing to do for ack here, ack is handled in ISR */
/* Flush the above write before enabling interrupts; otherwise,
* spurious interrupts will sometimes happen. To be 100% sure
* that the write has reached the device before interrupts are
* enabled, the mask register would have to be read back; however,
* this is not required for correctness, only to avoid wasting
* time on a large number of spurious interrupts. In testing,
* a sync reduced the observed spurious interrupts to zero.
*/
mb();
spin_unlock_irqrestore(&qe_ic_lock, flags);
}
@ -248,7 +240,7 @@ static struct irq_chip qe_ic_irq_chip = {
.typename = " QEIC ",
.unmask = qe_ic_unmask_irq,
.mask = qe_ic_mask_irq,
.mask_ack = qe_ic_mask_irq_and_ack,
.mask_ack = qe_ic_mask_irq,
};
static int qe_ic_host_match(struct irq_host *h, struct device_node *node)
@ -331,34 +323,22 @@ unsigned int qe_ic_get_high_irq(struct qe_ic *qe_ic)
return irq_linear_revmap(qe_ic->irqhost, irq);
}
/* FIXME: We mask all the QE Low interrupts while handling. We should
* let other interrupt come in, but BAD interrupts are generated */
void fastcall qe_ic_cascade_low(unsigned int irq, struct irq_desc *desc)
{
struct qe_ic *qe_ic = desc->handler_data;
struct irq_chip *chip = irq_desc[irq].chip;
unsigned int cascade_irq = qe_ic_get_low_irq(qe_ic);
chip->mask_ack(irq);
if (cascade_irq != NO_IRQ)
generic_handle_irq(cascade_irq);
chip->unmask(irq);
}
/* FIXME: We mask all the QE High interrupts while handling. We should
* let other interrupt come in, but BAD interrupts are generated */
void fastcall qe_ic_cascade_high(unsigned int irq, struct irq_desc *desc)
{
struct qe_ic *qe_ic = desc->handler_data;
struct irq_chip *chip = irq_desc[irq].chip;
unsigned int cascade_irq = qe_ic_get_high_irq(qe_ic);
chip->mask_ack(irq);
if (cascade_irq != NO_IRQ)
generic_handle_irq(cascade_irq);
chip->unmask(irq);
}
void __init qe_ic_init(struct device_node *node, unsigned int flags)