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0fabe1021f
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>
117 lines
3.2 KiB
C
117 lines
3.2 KiB
C
/*
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* DEC I/O ASIC interrupts.
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*
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* Copyright (c) 2002, 2003, 2013 Maciej W. Rozycki
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/irq.h>
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#include <linux/types.h>
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#include <asm/dec/ioasic.h>
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#include <asm/dec/ioasic_addrs.h>
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#include <asm/dec/ioasic_ints.h>
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static int ioasic_irq_base;
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static void unmask_ioasic_irq(struct irq_data *d)
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{
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u32 simr;
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simr = ioasic_read(IO_REG_SIMR);
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simr |= (1 << (d->irq - ioasic_irq_base));
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ioasic_write(IO_REG_SIMR, simr);
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}
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static void mask_ioasic_irq(struct irq_data *d)
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{
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u32 simr;
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simr = ioasic_read(IO_REG_SIMR);
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simr &= ~(1 << (d->irq - ioasic_irq_base));
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ioasic_write(IO_REG_SIMR, simr);
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}
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static void ack_ioasic_irq(struct irq_data *d)
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{
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mask_ioasic_irq(d);
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fast_iob();
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}
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static struct irq_chip ioasic_irq_type = {
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.name = "IO-ASIC",
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.irq_ack = ack_ioasic_irq,
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.irq_mask = mask_ioasic_irq,
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.irq_mask_ack = ack_ioasic_irq,
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.irq_unmask = unmask_ioasic_irq,
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};
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static void clear_ioasic_dma_irq(struct irq_data *d)
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{
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u32 sir;
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sir = ~(1 << (d->irq - ioasic_irq_base));
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ioasic_write(IO_REG_SIR, sir);
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fast_iob();
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}
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static struct irq_chip ioasic_dma_irq_type = {
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.name = "IO-ASIC-DMA",
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.irq_ack = clear_ioasic_dma_irq,
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.irq_mask = mask_ioasic_irq,
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.irq_unmask = unmask_ioasic_irq,
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.irq_eoi = clear_ioasic_dma_irq,
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};
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/*
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* I/O ASIC implements two kinds of DMA interrupts, informational and
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* error interrupts.
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*
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* The formers do not stop DMA and should be cleared as soon as possible
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* so that if they retrigger before the handler has completed, usually as
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* a side effect of actions taken by the handler, then they are reissued.
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* These use the `handle_edge_irq' handler that clears the request right
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* away.
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*
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* The latters stop DMA and do not resume it until the interrupt has been
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* cleared. This cannot be done until after a corrective action has been
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* taken and this also means they will not retrigger. Therefore they use
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* the `handle_fasteoi_irq' handler that only clears the request on the
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* way out. Because MIPS processor interrupt inputs, one of which the I/O
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* ASIC is cascaded to, are level-triggered it is recommended that error
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* DMA interrupt action handlers are registered with the IRQF_ONESHOT flag
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* set so that they are run with the interrupt line masked.
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*
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* This mask has `1' bits in the positions of informational interrupts.
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*/
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#define IO_IRQ_DMA_INFO \
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(IO_IRQ_MASK(IO_INR_SCC0A_RXDMA) | \
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IO_IRQ_MASK(IO_INR_SCC1A_RXDMA) | \
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IO_IRQ_MASK(IO_INR_ISDN_TXDMA) | \
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IO_IRQ_MASK(IO_INR_ISDN_RXDMA) | \
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IO_IRQ_MASK(IO_INR_ASC_DMA))
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void __init init_ioasic_irqs(int base)
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{
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int i;
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/* Mask interrupts. */
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ioasic_write(IO_REG_SIMR, 0);
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fast_iob();
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for (i = base; i < base + IO_INR_DMA; i++)
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irq_set_chip_and_handler(i, &ioasic_irq_type,
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handle_level_irq);
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for (; i < base + IO_IRQ_LINES; i++)
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irq_set_chip_and_handler(i, &ioasic_dma_irq_type,
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1 << (i - base) & IO_IRQ_DMA_INFO ?
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handle_edge_irq : handle_fasteoi_irq);
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ioasic_irq_base = base;
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}
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