Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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());
+}