1 files changed, 337 insertions, 0 deletions
diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c
new file mode 100644
index 000000000000..dc92b49d9204
--- /dev/null
+++ b/arch/x86/kernel/i8259.c
@@ -0,0 +1,337 @@
+#include <linux/linkage.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/timex.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/init.h>
+#include <linux/kernel_stat.h>
+#include <linux/sysdev.h>
+#include <linux/bitops.h>
+
+#include <asm/acpi.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/timer.h>
+#include <asm/hw_irq.h>
+#include <asm/pgtable.h>
+#include <asm/delay.h>
+#include <asm/desc.h>
+#include <asm/apic.h>
+#include <asm/arch_hooks.h>
+#include <asm/i8259.h>
+
+/*
+ * This is the 'legacy' 8259A Programmable Interrupt Controller,
+ * present in the majority of PC/AT boxes.
+ * plus some generic x86 specific things if generic specifics makes
+ * any sense at all.
+ */
+
+static int i8259A_auto_eoi;
+DEFINE_SPINLOCK(i8259A_lock);
+static void mask_and_ack_8259A(unsigned int);
+
+struct irq_chip i8259A_chip = {
+	.name		= "XT-PIC",
+	.mask		= disable_8259A_irq,
+	.disable	= disable_8259A_irq,
+	.unmask		= enable_8259A_irq,
+	.mask_ack	= mask_and_ack_8259A,
+};
+
+/*
+ * 8259A PIC functions to handle ISA devices:
+ */
+
+/*
+ * This contains the irq mask for both 8259A irq controllers,
+ */
+unsigned int cached_irq_mask = 0xffff;
+
+/*
+ * Not all IRQs can be routed through the IO-APIC, eg. on certain (older)
+ * boards the timer interrupt is not really connected to any IO-APIC pin,
+ * it's fed to the master 8259A's IR0 line only.
+ *
+ * Any '1' bit in this mask means the IRQ is routed through the IO-APIC.
+ * this 'mixed mode' IRQ handling costs nothing because it's only used
+ * at IRQ setup time.
+ */
+unsigned long io_apic_irqs;
+
+void disable_8259A_irq(unsigned int irq)
+{
+	unsigned int mask = 1 << irq;
+	unsigned long flags;
+
+	spin_lock_irqsave(&i8259A_lock, flags);
+	cached_irq_mask |= mask;
+	if (irq & 8)
+		outb(cached_slave_mask, PIC_SLAVE_IMR);
+	else
+		outb(cached_master_mask, PIC_MASTER_IMR);
+	spin_unlock_irqrestore(&i8259A_lock, flags);
+}
+
+void enable_8259A_irq(unsigned int irq)
+{
+	unsigned int mask = ~(1 << irq);
+	unsigned long flags;
+
+	spin_lock_irqsave(&i8259A_lock, flags);
+	cached_irq_mask &= mask;
+	if (irq & 8)
+		outb(cached_slave_mask, PIC_SLAVE_IMR);
+	else
+		outb(cached_master_mask, PIC_MASTER_IMR);
+	spin_unlock_irqrestore(&i8259A_lock, flags);
+}
+
+int i8259A_irq_pending(unsigned int irq)
+{
+	unsigned int mask = 1<<irq;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&i8259A_lock, flags);
+	if (irq < 8)
+		ret = inb(PIC_MASTER_CMD) & mask;
+	else
+		ret = inb(PIC_SLAVE_CMD) & (mask >> 8);
+	spin_unlock_irqrestore(&i8259A_lock, flags);
+
+	return ret;
+}
+
+void make_8259A_irq(unsigned int irq)
+{
+	disable_irq_nosync(irq);
+	io_apic_irqs &= ~(1<<irq);
+	set_irq_chip_and_handler_name(irq, &i8259A_chip, handle_level_irq,
+				      "XT");
+	enable_irq(irq);
+}
+
+/*
+ * This function assumes to be called rarely. Switching between
+ * 8259A registers is slow.
+ * This has to be protected by the irq controller spinlock
+ * before being called.
+ */
+static inline int i8259A_irq_real(unsigned int irq)
+{
+	int value;
+	int irqmask = 1<<irq;
+
+	if (irq < 8) {
+		outb(0x0B, PIC_MASTER_CMD);	/* ISR register */
+		value = inb(PIC_MASTER_CMD) & irqmask;
+		outb(0x0A, PIC_MASTER_CMD);	/* back to the IRR register */
+		return value;
+	}
+	outb(0x0B, PIC_SLAVE_CMD);	/* ISR register */
+	value = inb(PIC_SLAVE_CMD) & (irqmask >> 8);
+	outb(0x0A, PIC_SLAVE_CMD);	/* back to the IRR register */
+	return value;
+}
+
+/*
+ * Careful! The 8259A is a fragile beast, it pretty
+ * much _has_ to be done exactly like this (mask it
+ * first, _then_ send the EOI, and the order of EOI
+ * to the two 8259s is important!
+ */
+static void mask_and_ack_8259A(unsigned int irq)
+{
+	unsigned int irqmask = 1 << irq;
+	unsigned long flags;
+
+	spin_lock_irqsave(&i8259A_lock, flags);
+	/*
+	 * Lightweight spurious IRQ detection. We do not want
+	 * to overdo spurious IRQ handling - it's usually a sign
+	 * of hardware problems, so we only do the checks we can
+	 * do without slowing down good hardware unnecessarily.
+	 *
+	 * Note that IRQ7 and IRQ15 (the two spurious IRQs
+	 * usually resulting from the 8259A-1|2 PICs) occur
+	 * even if the IRQ is masked in the 8259A. Thus we
+	 * can check spurious 8259A IRQs without doing the
+	 * quite slow i8259A_irq_real() call for every IRQ.
+	 * This does not cover 100% of spurious interrupts,
+	 * but should be enough to warn the user that there
+	 * is something bad going on ...
+	 */
+	if (cached_irq_mask & irqmask)
+		goto spurious_8259A_irq;
+	cached_irq_mask |= irqmask;
+
+handle_real_irq:
+	if (irq & 8) {
+		inb(PIC_SLAVE_IMR);	/* DUMMY - (do we need this?) */
+		outb(cached_slave_mask, PIC_SLAVE_IMR);
+		/* 'Specific EOI' to slave */
+		outb(0x60+(irq&7), PIC_SLAVE_CMD);
+		 /* 'Specific EOI' to master-IRQ2 */
+		outb(0x60+PIC_CASCADE_IR, PIC_MASTER_CMD);
+	} else {
+		inb(PIC_MASTER_IMR);	/* DUMMY - (do we need this?) */
+		outb(cached_master_mask, PIC_MASTER_IMR);
+		outb(0x60+irq, PIC_MASTER_CMD);	/* 'Specific EOI to master */
+	}
+	spin_unlock_irqrestore(&i8259A_lock, flags);
+	return;
+
+spurious_8259A_irq:
+	/*
+	 * this is the slow path - should happen rarely.
+	 */
+	if (i8259A_irq_real(irq))
+		/*
+		 * oops, the IRQ _is_ in service according to the
+		 * 8259A - not spurious, go handle it.
+		 */
+		goto handle_real_irq;
+
+	{
+		static int spurious_irq_mask;
+		/*
+		 * At this point we can be sure the IRQ is spurious,
+		 * lets ACK and report it. [once per IRQ]
+		 */
+		if (!(spurious_irq_mask & irqmask)) {
+			printk(KERN_DEBUG
+			       "spurious 8259A interrupt: IRQ%d.\n", irq);
+			spurious_irq_mask |= irqmask;
+		}
+		atomic_inc(&irq_err_count);
+		/*
+		 * Theoretically we do not have to handle this IRQ,
+		 * but in Linux this does not cause problems and is
+		 * simpler for us.
+		 */
+		goto handle_real_irq;
+	}
+}
+
+static char irq_trigger[2];
+/**
+ * ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
+ */
+static void restore_ELCR(char *trigger)
+{
+	outb(trigger[0], 0x4d0);
+	outb(trigger[1], 0x4d1);
+}
+
+static void save_ELCR(char *trigger)
+{
+	/* IRQ 0,1,2,8,13 are marked as reserved */
+	trigger[0] = inb(0x4d0) & 0xF8;
+	trigger[1] = inb(0x4d1) & 0xDE;
+}
+
+static int i8259A_resume(struct sys_device *dev)
+{
+	init_8259A(i8259A_auto_eoi);
+	restore_ELCR(irq_trigger);
+	return 0;
+}
+
+static int i8259A_suspend(struct sys_device *dev, pm_message_t state)
+{
+	save_ELCR(irq_trigger);
+	return 0;
+}
+
+static int i8259A_shutdown(struct sys_device *dev)
+{
+	/* Put the i8259A into a quiescent state that
+	 * the kernel initialization code can get it
+	 * out of.
+	 */
+	outb(0xff, PIC_MASTER_IMR);	/* mask all of 8259A-1 */
+	outb(0xff, PIC_SLAVE_IMR);	/* mask all of 8259A-1 */
+	return 0;
+}
+
+static struct sysdev_class i8259_sysdev_class = {
+	.name = "i8259",
+	.suspend = i8259A_suspend,
+	.resume = i8259A_resume,
+	.shutdown = i8259A_shutdown,
+};
+
+static struct sys_device device_i8259A = {
+	.id	= 0,
+	.cls	= &i8259_sysdev_class,
+};
+
+static int __init i8259A_init_sysfs(void)
+{
+	int error = sysdev_class_register(&i8259_sysdev_class);
+	if (!error)
+		error = sysdev_register(&device_i8259A);
+	return error;
+}
+
+device_initcall(i8259A_init_sysfs);
+
+void init_8259A(int auto_eoi)
+{
+	unsigned long flags;
+
+	i8259A_auto_eoi = auto_eoi;
+
+	spin_lock_irqsave(&i8259A_lock, flags);
+
+	outb(0xff, PIC_MASTER_IMR);	/* mask all of 8259A-1 */
+	outb(0xff, PIC_SLAVE_IMR);	/* mask all of 8259A-2 */
+
+	/*
+	 * outb_pic - this has to work on a wide range of PC hardware.
+	 */
+	outb_pic(0x11, PIC_MASTER_CMD);	/* ICW1: select 8259A-1 init */
+
+	/* ICW2: 8259A-1 IR0-7 mapped to 0x30-0x37 on x86-64,
+	                       to 0x20-0x27 on i386 */
+	outb_pic(IRQ0_VECTOR, PIC_MASTER_IMR);
+
+	/* 8259A-1 (the master) has a slave on IR2 */
+	outb_pic(1U << PIC_CASCADE_IR, PIC_MASTER_IMR);
+
+	if (auto_eoi)	/* master does Auto EOI */
+		outb_pic(MASTER_ICW4_DEFAULT | PIC_ICW4_AEOI, PIC_MASTER_IMR);
+	else		/* master expects normal EOI */
+		outb_pic(MASTER_ICW4_DEFAULT, PIC_MASTER_IMR);
+
+	outb_pic(0x11, PIC_SLAVE_CMD);	/* ICW1: select 8259A-2 init */
+
+	/* ICW2: 8259A-2 IR0-7 mapped to IRQ8_VECTOR */
+	outb_pic(IRQ8_VECTOR, PIC_SLAVE_IMR);
+	/* 8259A-2 is a slave on master's IR2 */
+	outb_pic(PIC_CASCADE_IR, PIC_SLAVE_IMR);
+	/* (slave's support for AEOI in flat mode is to be investigated) */
+	outb_pic(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR);
+
+	if (auto_eoi)
+		/*
+		 * In AEOI mode we just have to mask the interrupt
+		 * when acking.
+		 */
+		i8259A_chip.mask_ack = disable_8259A_irq;
+	else
+		i8259A_chip.mask_ack = mask_and_ack_8259A;
+
+	udelay(100);		/* wait for 8259A to initialize */
+
+	outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
+	outb(cached_slave_mask, PIC_SLAVE_IMR);	  /* restore slave IRQ mask */
+
+	spin_unlock_irqrestore(&i8259A_lock, flags);
+}