1 files changed, 112 insertions, 0 deletions
diff --git a/arch/mips/dec/ioasic-irq.c b/arch/mips/dec/ioasic-irq.c
new file mode 100644
index 000000000..130eb67bd
--- /dev/null
+++ b/arch/mips/dec/ioasic-irq.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	DEC I/O ASIC interrupts.
+ *
+ *	Copyright (c) 2002, 2003, 2013  Maciej W. Rozycki
+ */
+
+#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;
+}