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MIPS: DECstation I/O ASIC DMA interrupt classes

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This change complements commits d0da7c002f7b2a93582187a9e3f73891a01d8ee4
[MIPS: DEC: Convert to new irq_chip functions] and
5359b938c0 [MIPS: DECstation I/O ASIC DMA
interrupt handling fix] and implements automatic handling of the two
classes of DMA interrupts the I/O ASIC implements, informational and
errors.

Informational DMA interrupts do not stop the transfer and use the
`handle_edge_irq' handler that clears the request right away so that
another request may be recorded while the previous is being handled.

DMA error interrupts stop the transfer and require a corrective action
before DMA can be reenabled.  Therefore they use the `handle_fasteoi_irq'
handler that only clears the request on the way out.  Because MIPS
processor interrupt inputs, one of which the I/O ASIC's interrupt
controller is cascaded to, are level-triggered it is recommended that
error DMA interrupt action handlers are registered with the IRQF_ONESHOT
flag set so that they are run with the interrupt line masked.

This change removes the export of clear_ioasic_dma_irq that now does not
have to be called by device drivers to clear interrupts explicitly
anymore.  Originally these interrupts were cleared in the .end handler of
the `irq_chip' structure, before it was removed.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5874/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Maciej W. Rozycki
2013-09-22 21:55:19 +01:00
committed by Ralf Baechle
parent 4e7f72660c
commit 0fabe1021f
3 changed files with 38 additions and 10 deletions
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3
drivers/net/ethernet/amd/declance.c
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@@ -725,7 +725,6 @@ static irqreturn_t lance_dma_merr_int(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
clear_ioasic_dma_irq(irq);
printk(KERN_ERR "%s: DMA error\n", dev->name);
return IRQ_HANDLED;
}
@@ -812,7 +811,7 @@ static int lance_open(struct net_device *dev)
if (lp->dma_irq >= 0) {
unsigned long flags;
if (request_irq(lp->dma_irq, lance_dma_merr_int, 0,
if (request_irq(lp->dma_irq, lance_dma_merr_int, IRQF_ONESHOT,
"lance error", dev)) {
free_irq(dev->irq, dev);
printk("%s: Can't get DMA IRQ %d\n", dev->name,