1 files changed, 429 insertions, 0 deletions
diff --git a/arch/i386/kernel/i8259.c b/arch/i386/kernel/i8259.c
new file mode 100644
index 0000000..560bef1
--- /dev/null
+++ b/arch/i386/kernel/i8259.c
@@ -0,0 +1,429 @@
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/kernel_stat.h>
+#include <linux/sysdev.h>
+#include <linux/bitops.h>
+
+#include <asm/8253pit.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/timer.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>
+
+#include <linux/irq.h>
+
+#include <io_ports.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.
+ * this file should become arch/i386/kernel/irq.c when the old irq.c
+ * moves to arch independent land
+ */
+
+DEFINE_SPINLOCK(i8259A_lock);
+
+static void end_8259A_irq (unsigned int irq)
+{
+	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)) &&
+							irq_desc[irq].action)
+		enable_8259A_irq(irq);
+}
+
+#define shutdown_8259A_irq	disable_8259A_irq
+
+static void mask_and_ack_8259A(unsigned int);
+
+unsigned int startup_8259A_irq(unsigned int irq)
+{ 
+	enable_8259A_irq(irq);
+	return 0; /* never anything pending */
+}
+
+static struct hw_interrupt_type i8259A_irq_type = {
+	.typename = "XT-PIC",
+	.startup = startup_8259A_irq,
+	.shutdown = shutdown_8259A_irq,
+	.enable = enable_8259A_irq,
+	.disable = disable_8259A_irq,
+	.ack = mask_and_ack_8259A,
+	.end = end_8259A_irq,
+};
+
+/*
+ * 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);
+	irq_desc[irq].handler = &i8259A_irq_type;
+	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 unnecesserily.
+	 *
+	 * 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);
+		outb(0x60+(irq&7),PIC_SLAVE_CMD);/* 'Specific EOI' to slave */
+		outb(0x60+PIC_CASCADE_IR,PIC_MASTER_CMD); /* 'Specific EOI' to master-IRQ2 */
+	} 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(0);
+	restore_ELCR(irq_trigger);
+	return 0;
+}
+
+static int i8259A_suspend(struct sys_device *dev, u32 state)
+{
+	save_ELCR(irq_trigger);
+	return 0;
+}
+
+static struct sysdev_class i8259_sysdev_class = {
+	set_kset_name("i8259"),
+	.suspend = i8259A_suspend,
+	.resume = i8259A_resume,
+};
+
+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;
+
+	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_p - this has to work on a wide range of PC hardware.
+	 */
+	outb_p(0x11, PIC_MASTER_CMD);	/* ICW1: select 8259A-1 init */
+	outb_p(0x20 + 0, PIC_MASTER_IMR);	/* ICW2: 8259A-1 IR0-7 mapped to 0x20-0x27 */
+	outb_p(1U << PIC_CASCADE_IR, PIC_MASTER_IMR);	/* 8259A-1 (the master) has a slave on IR2 */
+	if (auto_eoi)	/* master does Auto EOI */
+		outb_p(MASTER_ICW4_DEFAULT | PIC_ICW4_AEOI, PIC_MASTER_IMR);
+	else		/* master expects normal EOI */
+		outb_p(MASTER_ICW4_DEFAULT, PIC_MASTER_IMR);
+
+	outb_p(0x11, PIC_SLAVE_CMD);	/* ICW1: select 8259A-2 init */
+	outb_p(0x20 + 8, PIC_SLAVE_IMR);	/* ICW2: 8259A-2 IR0-7 mapped to 0x28-0x2f */
+	outb_p(PIC_CASCADE_IR, PIC_SLAVE_IMR);	/* 8259A-2 is a slave on master's IR2 */
+	outb_p(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR); /* (slave's support for AEOI in flat mode is to be investigated) */
+	if (auto_eoi)
+		/*
+		 * in AEOI mode we just have to mask the interrupt
+		 * when acking.
+		 */
+		i8259A_irq_type.ack = disable_8259A_irq;
+	else
+		i8259A_irq_type.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);
+}
+
+/*
+ * Note that on a 486, we don't want to do a SIGFPE on an irq13
+ * as the irq is unreliable, and exception 16 works correctly
+ * (ie as explained in the intel literature). On a 386, you
+ * can't use exception 16 due to bad IBM design, so we have to
+ * rely on the less exact irq13.
+ *
+ * Careful.. Not only is IRQ13 unreliable, but it is also
+ * leads to races. IBM designers who came up with it should
+ * be shot.
+ */
+ 
+
+static irqreturn_t math_error_irq(int cpl, void *dev_id, struct pt_regs *regs)
+{
+	extern void math_error(void __user *);
+	outb(0,0xF0);
+	if (ignore_fpu_irq || !boot_cpu_data.hard_math)
+		return IRQ_NONE;
+	math_error((void __user *)regs->eip);
+	return IRQ_HANDLED;
+}
+
+/*
+ * New motherboards sometimes make IRQ 13 be a PCI interrupt,
+ * so allow interrupt sharing.
+ */
+static struct irqaction fpu_irq = { math_error_irq, 0, CPU_MASK_NONE, "fpu", NULL, NULL };
+
+void __init init_ISA_irqs (void)
+{
+	int i;
+
+#ifdef CONFIG_X86_LOCAL_APIC
+	init_bsp_APIC();
+#endif
+	init_8259A(0);
+
+	for (i = 0; i < NR_IRQS; i++) {
+		irq_desc[i].status = IRQ_DISABLED;
+		irq_desc[i].action = NULL;
+		irq_desc[i].depth = 1;
+
+		if (i < 16) {
+			/*
+			 * 16 old-style INTA-cycle interrupts:
+			 */
+			irq_desc[i].handler = &i8259A_irq_type;
+		} else {
+			/*
+			 * 'high' PCI IRQs filled in on demand
+			 */
+			irq_desc[i].handler = &no_irq_type;
+		}
+	}
+}
+
+void __init init_IRQ(void)
+{
+	int i;
+
+	/* all the set up before the call gates are initialised */
+	pre_intr_init_hook();
+
+	/*
+	 * Cover the whole vector space, no vector can escape
+	 * us. (some of these will be overridden and become
+	 * 'special' SMP interrupts)
+	 */
+	for (i = 0; i < (NR_VECTORS - FIRST_EXTERNAL_VECTOR); i++) {
+		int vector = FIRST_EXTERNAL_VECTOR + i;
+		if (i >= NR_IRQS)
+			break;
+		if (vector != SYSCALL_VECTOR) 
+			set_intr_gate(vector, interrupt[i]);
+	}
+
+	/* setup after call gates are initialised (usually add in
+	 * the architecture specific gates)
+	 */
+	intr_init_hook();
+
+	/*
+	 * Set the clock to HZ Hz, we already have a valid
+	 * vector now:
+	 */
+	setup_pit_timer();
+
+	/*
+	 * External FPU? Set up irq13 if so, for
+	 * original braindamaged IBM FERR coupling.
+	 */
+	if (boot_cpu_data.hard_math && !cpu_has_fpu)
+		setup_irq(FPU_IRQ, &fpu_irq);
+
+	irq_ctx_init(smp_processor_id());
+}