1 files changed, 282 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
new file mode 100644
index 000000000..c1d76c344
--- /dev/null
+++ b/arch/powerpc/sysdev/i8259.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * i8259 interrupt controller driver.
+ */
+#undef DEBUG
+
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <asm/io.h>
+#include <asm/i8259.h>
+#include <asm/prom.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_RAW_SPINLOCK(i8259_lock);
+
+static struct irq_domain *i8259_host;
+
+/*
+ * 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.
+ */
+unsigned int i8259_irq(void)
+{
+	int irq;
+	int lock = 0;
+
+	/* Either int-ack or poll for the IRQ */
+	if (pci_intack)
+		irq = readb(pci_intack);
+	else {
+		raw_spin_lock(&i8259_lock);
+		lock = 1;
+
+		/* 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 = 0;
+	} else if (irq == 0xff)
+		irq = 0;
+
+	if (lock)
+		raw_spin_unlock(&i8259_lock);
+	return irq;
+}
+
+static void i8259_mask_and_ack_irq(struct irq_data *d)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&i8259_lock, flags);
+	if (d->irq > 7) {
+		cached_A1 |= 1 << (d->irq-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 << d->irq;
+		inb(0x21); 	/* DUMMY */
+		outb(cached_21, 0x21);
+		outb(0x20, 0x20);	/* Non-specific EOI */
+	}
+	raw_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(struct irq_data *d)
+{
+	unsigned long flags;
+
+	pr_debug("i8259_mask_irq(%d)\n", d->irq);
+
+	raw_spin_lock_irqsave(&i8259_lock, flags);
+	if (d->irq < 8)
+		cached_21 |= 1 << d->irq;
+	else
+		cached_A1 |= 1 << (d->irq-8);
+	i8259_set_irq_mask(d->irq);
+	raw_spin_unlock_irqrestore(&i8259_lock, flags);
+}
+
+static void i8259_unmask_irq(struct irq_data *d)
+{
+	unsigned long flags;
+
+	pr_debug("i8259_unmask_irq(%d)\n", d->irq);
+
+	raw_spin_lock_irqsave(&i8259_lock, flags);
+	if (d->irq < 8)
+		cached_21 &= ~(1 << d->irq);
+	else
+		cached_A1 &= ~(1 << (d->irq-8));
+	i8259_set_irq_mask(d->irq);
+	raw_spin_unlock_irqrestore(&i8259_lock, flags);
+}
+
+static struct irq_chip i8259_pic = {
+	.name		= "i8259",
+	.irq_mask	= i8259_mask_irq,
+	.irq_disable	= i8259_mask_irq,
+	.irq_unmask	= i8259_unmask_irq,
+	.irq_mask_ack	= i8259_mask_and_ack_irq,
+};
+
+static struct resource pic1_iores = {
+	.name = "8259 (master)",
+	.start = 0x20,
+	.end = 0x21,
+	.flags = IORESOURCE_IO | IORESOURCE_BUSY,
+};
+
+static struct resource pic2_iores = {
+	.name = "8259 (slave)",
+	.start = 0xa0,
+	.end = 0xa1,
+	.flags = IORESOURCE_IO | IORESOURCE_BUSY,
+};
+
+static struct resource pic_edgectrl_iores = {
+	.name = "8259 edge control",
+	.start = 0x4d0,
+	.end = 0x4d1,
+	.flags = IORESOURCE_IO | IORESOURCE_BUSY,
+};
+
+static int i8259_host_match(struct irq_domain *h, struct device_node *node,
+			    enum irq_domain_bus_token bus_token)
+{
+	struct device_node *of_node = irq_domain_get_of_node(h);
+	return of_node == NULL || of_node == node;
+}
+
+static int i8259_host_map(struct irq_domain *h, unsigned int virq,
+			  irq_hw_number_t hw)
+{
+	pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
+
+	/* We block the internal cascade */
+	if (hw == 2)
+		irq_set_status_flags(virq, IRQ_NOREQUEST);
+
+	/* We use the level handler only for now, we might want to
+	 * be more cautious here but that works for now
+	 */
+	irq_set_status_flags(virq, IRQ_LEVEL);
+	irq_set_chip_and_handler(virq, &i8259_pic, handle_level_irq);
+	return 0;
+}
+
+static int i8259_host_xlate(struct irq_domain *h, struct device_node *ct,
+			    const u32 *intspec, unsigned int intsize,
+			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
+{
+	static unsigned char map_isa_senses[4] = {
+		IRQ_TYPE_LEVEL_LOW,
+		IRQ_TYPE_LEVEL_HIGH,
+		IRQ_TYPE_EDGE_FALLING,
+		IRQ_TYPE_EDGE_RISING,
+	};
+
+	*out_hwirq = intspec[0];
+	if (intsize > 1 && intspec[1] < 4)
+		*out_flags = map_isa_senses[intspec[1]];
+	else
+		*out_flags = IRQ_TYPE_NONE;
+
+	return 0;
+}
+
+static const struct irq_domain_ops i8259_host_ops = {
+	.match = i8259_host_match,
+	.map = i8259_host_map,
+	.xlate = i8259_host_xlate,
+};
+
+struct irq_domain *i8259_get_host(void)
+{
+	return i8259_host;
+}
+
+/**
+ * i8259_init - Initialize the legacy controller
+ * @node: device node of the legacy PIC (can be NULL, but then, it will match
+ *        all interrupts, so beware)
+ * @intack_addr: PCI interrupt acknowledge (real) address which will return
+ *             	 the active irq from the 8259
+ */
+void i8259_init(struct device_node *node, unsigned long intack_addr)
+{
+	unsigned long flags;
+
+	/* initialize the controller */
+	raw_spin_lock_irqsave(&i8259_lock, flags);
+
+	/* Mask all first */
+	outb(0xff, 0xA1);
+	outb(0xff, 0x21);
+
+	/* init master interrupt controller */
+	outb(0x11, 0x20); /* Start init sequence */
+	outb(0x00, 0x21); /* Vector base */
+	outb(0x04, 0x21); /* edge triggered, 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 */
+
+	/* That thing is slow */
+	udelay(100);
+
+	/* always read ISR */
+	outb(0x0B, 0x20);
+	outb(0x0B, 0xA0);
+
+	/* Unmask the internal cascade */
+	cached_21 &= ~(1 << 2);
+
+	/* Set interrupt masks */
+	outb(cached_A1, 0xA1);
+	outb(cached_21, 0x21);
+
+	raw_spin_unlock_irqrestore(&i8259_lock, flags);
+
+	/* create a legacy host */
+	i8259_host = irq_domain_add_legacy_isa(node, &i8259_host_ops, NULL);
+	if (i8259_host == NULL) {
+		printk(KERN_ERR "i8259: failed to allocate irq host !\n");
+		return;
+	}
+
+	/* reserve our resources */
+	/* XXX should we continue doing that ? it seems to cause problems
+	 * with further requesting of PCI IO resources for that range...
+	 * need to look into it.
+	 */
+	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);
+
+	printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");
+}