2 files changed, 222 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index e66fef6..f3c9e61 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_MPIC)		+= mpic.o
 obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o
+obj-$(CONFIG_PPC_I8259)		+= i8259.o
diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
new file mode 100644
index 0000000..90bce6e
--- /dev/null
+++ b/arch/powerpc/sysdev/i8259.c
@@ -0,0 +1,221 @@
+/*
+ * i8259 interrupt controller driver.
+ *
+ * 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/ioport.h>
+#include <linux/interrupt.h>
+#include <asm/io.h>
+#include <asm/i8259.h>
+
+static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
+
+static unsigned char cached_8259[2] = { 0xff, 0xff };
+#define cached_A1 (cached_8259[0])
+#define cached_21 (cached_8259[1])
+
+static DEFINE_SPINLOCK(i8259_lock);
+
+static int i8259_pic_irq_offset;
+
+/*
+ * Acknowledge the IRQ using either the PCI host bridge's interrupt
+ * acknowledge feature or poll.  How i8259_init() is called determines
+ * which is called.  It should be noted that polling is broken on some
+ * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
+ */
+int i8259_irq(struct pt_regs *regs)
+{
+	int irq;
+
+	spin_lock(&i8259_lock);
+
+	/* Either int-ack or poll for the IRQ */
+	if (pci_intack)
+		irq = readb(pci_intack);
+	else {
+		/* Perform an interrupt acknowledge cycle on controller 1. */
+		outb(0x0C, 0x20);		/* prepare for poll */
+		irq = inb(0x20) & 7;
+		if (irq == 2 ) {
+			/*
+			 * Interrupt is cascaded so perform interrupt
+			 * acknowledge on controller 2.
+			 */
+			outb(0x0C, 0xA0);	/* prepare for poll */
+			irq = (inb(0xA0) & 7) + 8;
+		}
+	}
+
+	if (irq == 7) {
+		/*
+		 * This may be a spurious interrupt.
+		 *
+		 * Read the interrupt status register (ISR). If the most
+		 * significant bit is not set then there is no valid
+		 * interrupt.
+		 */
+		if (!pci_intack)
+			outb(0x0B, 0x20);	/* ISR register */
+		if(~inb(0x20) & 0x80)
+			irq = -1;
+	}
+
+	spin_unlock(&i8259_lock);
+	return irq + i8259_pic_irq_offset;
+}
+
+int i8259_irq_cascade(struct pt_regs *regs, void *unused)
+{
+	return i8259_irq(regs);
+}
+
+static void i8259_mask_and_ack_irq(unsigned int irq_nr)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&i8259_lock, flags);
+	irq_nr -= i8259_pic_irq_offset;
+	if (irq_nr > 7) {
+		cached_A1 |= 1 << (irq_nr-8);
+		inb(0xA1); 	/* DUMMY */
+		outb(cached_A1, 0xA1);
+		outb(0x20, 0xA0);	/* Non-specific EOI */
+		outb(0x20, 0x20);	/* Non-specific EOI to cascade */
+	} else {
+		cached_21 |= 1 << irq_nr;
+		inb(0x21); 	/* DUMMY */
+		outb(cached_21, 0x21);
+		outb(0x20, 0x20);	/* Non-specific EOI */
+	}
+	spin_unlock_irqrestore(&i8259_lock, flags);
+}
+
+static void i8259_set_irq_mask(int irq_nr)
+{
+	outb(cached_A1,0xA1);
+	outb(cached_21,0x21);
+}
+
+static void i8259_mask_irq(unsigned int irq_nr)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&i8259_lock, flags);
+	irq_nr -= i8259_pic_irq_offset;
+	if (irq_nr < 8)
+		cached_21 |= 1 << irq_nr;
+	else
+		cached_A1 |= 1 << (irq_nr-8);
+	i8259_set_irq_mask(irq_nr);
+	spin_unlock_irqrestore(&i8259_lock, flags);
+}
+
+static void i8259_unmask_irq(unsigned int irq_nr)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&i8259_lock, flags);
+	irq_nr -= i8259_pic_irq_offset;
+	if (irq_nr < 8)
+		cached_21 &= ~(1 << irq_nr);
+	else
+		cached_A1 &= ~(1 << (irq_nr-8));
+	i8259_set_irq_mask(irq_nr);
+	spin_unlock_irqrestore(&i8259_lock, flags);
+}
+
+static void i8259_end_irq(unsigned int irq)
+{
+	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS))
+	    && irq_desc[irq].action)
+		i8259_unmask_irq(irq);
+}
+
+struct hw_interrupt_type i8259_pic = {
+	.typename = " i8259    ",
+	.enable = i8259_unmask_irq,
+	.disable = i8259_mask_irq,
+	.ack = i8259_mask_and_ack_irq,
+	.end = i8259_end_irq,
+};
+
+static struct resource pic1_iores = {
+	.name = "8259 (master)",
+	.start = 0x20,
+	.end = 0x21,
+	.flags = IORESOURCE_BUSY,
+};
+
+static struct resource pic2_iores = {
+	.name = "8259 (slave)",
+	.start = 0xa0,
+	.end = 0xa1,
+	.flags = IORESOURCE_BUSY,
+};
+
+static struct resource pic_edgectrl_iores = {
+	.name = "8259 edge control",
+	.start = 0x4d0,
+	.end = 0x4d1,
+	.flags = IORESOURCE_BUSY,
+};
+
+static struct irqaction i8259_irqaction = {
+	.handler = no_action,
+	.flags = SA_INTERRUPT,
+	.mask = CPU_MASK_NONE,
+	.name = "82c59 secondary cascade",
+};
+
+/*
+ * i8259_init()
+ * intack_addr - PCI interrupt acknowledge (real) address which will return
+ *               the active irq from the 8259
+ */
+void __init i8259_init(unsigned long intack_addr, int offset)
+{
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&i8259_lock, flags);
+	i8259_pic_irq_offset = offset;
+
+	/* init master interrupt controller */
+	outb(0x11, 0x20); /* Start init sequence */
+	outb(0x00, 0x21); /* Vector base */
+	outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
+	outb(0x01, 0x21); /* Select 8086 mode */
+
+	/* init slave interrupt controller */
+	outb(0x11, 0xA0); /* Start init sequence */
+	outb(0x08, 0xA1); /* Vector base */
+	outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
+	outb(0x01, 0xA1); /* Select 8086 mode */
+
+	/* always read ISR */
+	outb(0x0B, 0x20);
+	outb(0x0B, 0xA0);
+
+	/* Mask all interrupts */
+	outb(cached_A1, 0xA1);
+	outb(cached_21, 0x21);
+
+	spin_unlock_irqrestore(&i8259_lock, flags);
+
+	/* reserve our resources */
+	setup_irq(offset + 2, &i8259_irqaction);
+	request_resource(&ioport_resource, &pic1_iores);
+	request_resource(&ioport_resource, &pic2_iores);
+	request_resource(&ioport_resource, &pic_edgectrl_iores);
+
+	if (intack_addr != 0)
+		pci_intack = ioremap(intack_addr, 1);
+
+	for (i = 0; i < NUM_ISA_INTERRUPTS; ++i)
+		irq_desc[offset + i].handler = &i8259_pic;
+}