ioasic-irq.c
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/*
* DEC I/O ASIC interrupts.
*
* Copyright (c) 2002, 2003, 2013 Maciej W. Rozycki
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/types.h>
#include <asm/dec/ioasic.h>
#include <asm/dec/ioasic_addrs.h>
#include <asm/dec/ioasic_ints.h>
static int ioasic_irq_base;
static void unmask_ioasic_irq(struct irq_data *d)
{
u32 simr;
simr = ioasic_read(IO_REG_SIMR);
simr |= (1 << (d->irq - ioasic_irq_base));
ioasic_write(IO_REG_SIMR, simr);
}
static void mask_ioasic_irq(struct irq_data *d)
{
u32 simr;
simr = ioasic_read(IO_REG_SIMR);
simr &= ~(1 << (d->irq - ioasic_irq_base));
ioasic_write(IO_REG_SIMR, simr);
}
static void ack_ioasic_irq(struct irq_data *d)
{
mask_ioasic_irq(d);
fast_iob();
}
static struct irq_chip ioasic_irq_type = {
.name = "IO-ASIC",
.irq_ack = ack_ioasic_irq,
.irq_mask = mask_ioasic_irq,
.irq_mask_ack = ack_ioasic_irq,
.irq_unmask = unmask_ioasic_irq,
};
static void clear_ioasic_dma_irq(struct irq_data *d)
{
u32 sir;
sir = ~(1 << (d->irq - ioasic_irq_base));
ioasic_write(IO_REG_SIR, sir);
fast_iob();
}
static struct irq_chip ioasic_dma_irq_type = {
.name = "IO-ASIC-DMA",
.irq_ack = clear_ioasic_dma_irq,
.irq_mask = mask_ioasic_irq,
.irq_unmask = unmask_ioasic_irq,
.irq_eoi = clear_ioasic_dma_irq,
};
/*
* I/O ASIC implements two kinds of DMA interrupts, informational and
* error interrupts.
*
* The formers do not stop DMA and should be cleared as soon as possible
* so that if they retrigger before the handler has completed, usually as
* a side effect of actions taken by the handler, then they are reissued.
* These use the `handle_edge_irq' handler that clears the request right
* away.
*
* The latters stop DMA and do not resume it until the interrupt has been
* cleared. This cannot be done until after a corrective action has been
* taken and this also means they will not retrigger. 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 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 mask has `1' bits in the positions of informational interrupts.
*/
#define IO_IRQ_DMA_INFO \
(IO_IRQ_MASK(IO_INR_SCC0A_RXDMA) | \
IO_IRQ_MASK(IO_INR_SCC1A_RXDMA) | \
IO_IRQ_MASK(IO_INR_ISDN_TXDMA) | \
IO_IRQ_MASK(IO_INR_ISDN_RXDMA) | \
IO_IRQ_MASK(IO_INR_ASC_DMA))
void __init init_ioasic_irqs(int base)
{
int i;
/* Mask interrupts. */
ioasic_write(IO_REG_SIMR, 0);
fast_iob();
for (i = base; i < base + IO_INR_DMA; i++)
irq_set_chip_and_handler(i, &ioasic_irq_type,
handle_level_irq);
for (; i < base + IO_IRQ_LINES; i++)
irq_set_chip_and_handler(i, &ioasic_dma_irq_type,
1 << (i - base) & IO_IRQ_DMA_INFO ?
handle_edge_irq : handle_fasteoi_irq);
ioasic_irq_base = base;
}