| /* |
| * linux/kernel/irq.c |
| * |
| * Copyright (C) 1992 Linus Torvalds |
| * |
| * This file contains the code used by various IRQ handling routines: |
| * asking for different IRQ's should be done through these routines |
| * instead of just grabbing them. Thus setups with different IRQ numbers |
| * shouldn't result in any weird surprises, and installing new handlers |
| * should be easier. |
| */ |
| |
| /* |
| * IRQ's are in fact implemented a bit like signal handlers for the kernel. |
| * The same sigaction struct is used, and with similar semantics (ie there |
| * is a SA_INTERRUPT flag etc). Naturally it's not a 1:1 relation, but there |
| * are similarities. |
| * |
| * sa_handler(int irq_NR) is the default function called. |
| * sa_mask is 0 if nothing uses this IRQ |
| * sa_flags contains various info: SA_INTERRUPT etc |
| * sa_restorer is the unused |
| */ |
| |
| #include <linux/ptrace.h> |
| #include <linux/errno.h> |
| #include <linux/signal.h> |
| #include <linux/sched.h> |
| #include <linux/interrupt.h> |
| |
| #include <asm/system.h> |
| #include <asm/io.h> |
| #include <asm/irq.h> |
| |
| #define CR0_NE 32 |
| |
| static unsigned char cache_21 = 0xff; |
| static unsigned char cache_A1 = 0xff; |
| |
| unsigned long intr_count = 0; |
| unsigned long bh_active = 0; |
| unsigned long bh_mask = 0xFFFFFFFF; |
| struct bh_struct bh_base[32]; |
| |
| /* |
| * do_bottom_half() runs at normal kernel priority: all interrupts |
| * enabled. do_bottom_half() is atomic with respect to itself: a |
| * bottom_half handler need not be re-entrant. |
| */ |
| extern "C" void do_bottom_half(void) |
| { |
| unsigned long active; |
| unsigned long mask, left; |
| struct bh_struct *bh; |
| |
| bh = bh_base; |
| active = bh_active & bh_mask; |
| for (mask = 1, left = ~0 ; left & active ; bh++,mask += mask,left += left) { |
| if (mask & active) { |
| void (*fn)(void *); |
| bh_active &= ~mask; |
| fn = bh->routine; |
| if (!fn) |
| goto bad_bh; |
| fn(bh->data); |
| } |
| } |
| return; |
| bad_bh: |
| printk ("irq.c:bad bottom half entry\n"); |
| } |
| |
| /* |
| * This builds up the IRQ handler stubs using some ugly macros in irq.h |
| * |
| * These macros create the low-level assembly IRQ routines that do all |
| * the operations that are needed to keep the AT interrupt-controller |
| * happy. They are also written to be fast - and to disable interrupts |
| * as little as humanly possible. |
| * |
| * NOTE! These macros expand to three different handlers for each line: one |
| * complete handler that does all the fancy stuff (including signal handling), |
| * and one fast handler that is meant for simple IRQ's that want to be |
| * atomic. The specific handler is chosen depending on the SA_INTERRUPT |
| * flag when installing a handler. Finally, one "bad interrupt" handler, that |
| * is used when no handler is present. |
| */ |
| BUILD_IRQ(FIRST,0,0x01) |
| BUILD_IRQ(FIRST,1,0x02) |
| BUILD_IRQ(FIRST,2,0x04) |
| BUILD_IRQ(FIRST,3,0x08) |
| BUILD_IRQ(FIRST,4,0x10) |
| BUILD_IRQ(FIRST,5,0x20) |
| BUILD_IRQ(FIRST,6,0x40) |
| BUILD_IRQ(FIRST,7,0x80) |
| BUILD_IRQ(SECOND,8,0x01) |
| BUILD_IRQ(SECOND,9,0x02) |
| BUILD_IRQ(SECOND,10,0x04) |
| BUILD_IRQ(SECOND,11,0x08) |
| BUILD_IRQ(SECOND,12,0x10) |
| BUILD_IRQ(SECOND,13,0x20) |
| BUILD_IRQ(SECOND,14,0x40) |
| BUILD_IRQ(SECOND,15,0x80) |
| |
| /* |
| * Pointers to the low-level handlers: first the general ones, then the |
| * fast ones, then the bad ones. |
| */ |
| static void (*interrupt[16])(void) = { |
| IRQ0_interrupt, IRQ1_interrupt, IRQ2_interrupt, IRQ3_interrupt, |
| IRQ4_interrupt, IRQ5_interrupt, IRQ6_interrupt, IRQ7_interrupt, |
| IRQ8_interrupt, IRQ9_interrupt, IRQ10_interrupt, IRQ11_interrupt, |
| IRQ12_interrupt, IRQ13_interrupt, IRQ14_interrupt, IRQ15_interrupt |
| }; |
| |
| static void (*fast_interrupt[16])(void) = { |
| fast_IRQ0_interrupt, fast_IRQ1_interrupt, |
| fast_IRQ2_interrupt, fast_IRQ3_interrupt, |
| fast_IRQ4_interrupt, fast_IRQ5_interrupt, |
| fast_IRQ6_interrupt, fast_IRQ7_interrupt, |
| fast_IRQ8_interrupt, fast_IRQ9_interrupt, |
| fast_IRQ10_interrupt, fast_IRQ11_interrupt, |
| fast_IRQ12_interrupt, fast_IRQ13_interrupt, |
| fast_IRQ14_interrupt, fast_IRQ15_interrupt |
| }; |
| |
| static void (*bad_interrupt[16])(void) = { |
| bad_IRQ0_interrupt, bad_IRQ1_interrupt, |
| bad_IRQ2_interrupt, bad_IRQ3_interrupt, |
| bad_IRQ4_interrupt, bad_IRQ5_interrupt, |
| bad_IRQ6_interrupt, bad_IRQ7_interrupt, |
| bad_IRQ8_interrupt, bad_IRQ9_interrupt, |
| bad_IRQ10_interrupt, bad_IRQ11_interrupt, |
| bad_IRQ12_interrupt, bad_IRQ13_interrupt, |
| bad_IRQ14_interrupt, bad_IRQ15_interrupt |
| }; |
| |
| /* |
| * Initial irq handlers. |
| */ |
| static struct sigaction irq_sigaction[16] = { |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }, |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }, |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }, |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }, |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }, |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }, |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }, |
| { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL } |
| }; |
| |
| /* |
| * do_IRQ handles IRQ's that have been installed without the |
| * SA_INTERRUPT flag: it uses the full signal-handling return |
| * and runs with other interrupts enabled. All relatively slow |
| * IRQ's should use this format: notably the keyboard/timer |
| * routines. |
| */ |
| extern "C" void do_IRQ(int irq, struct pt_regs * regs) |
| { |
| struct sigaction * sa = irq + irq_sigaction; |
| |
| sa->sa_handler((int) regs); |
| } |
| |
| /* |
| * do_fast_IRQ handles IRQ's that don't need the fancy interrupt return |
| * stuff - the handler is also running with interrupts disabled unless |
| * it explicitly enables them later. |
| */ |
| extern "C" void do_fast_IRQ(int irq) |
| { |
| struct sigaction * sa = irq + irq_sigaction; |
| |
| sa->sa_handler(irq); |
| } |
| |
| int irqaction(unsigned int irq, struct sigaction * new_sa) |
| { |
| struct sigaction * sa; |
| unsigned long flags; |
| |
| if (irq > 15) |
| return -EINVAL; |
| sa = irq + irq_sigaction; |
| if (sa->sa_mask) |
| return -EBUSY; |
| if (!new_sa->sa_handler) |
| return -EINVAL; |
| save_flags(flags); |
| cli(); |
| *sa = *new_sa; |
| sa->sa_mask = 1; |
| if (sa->sa_flags & SA_INTERRUPT) |
| set_intr_gate(0x20+irq,fast_interrupt[irq]); |
| else |
| set_intr_gate(0x20+irq,interrupt[irq]); |
| if (irq < 8) { |
| cache_21 &= ~(1<<irq); |
| outb(cache_21,0x21); |
| } else { |
| cache_21 &= ~(1<<2); |
| cache_A1 &= ~(1<<(irq-8)); |
| outb(cache_21,0x21); |
| outb(cache_A1,0xA1); |
| } |
| restore_flags(flags); |
| return 0; |
| } |
| |
| int request_irq(unsigned int irq, void (*handler)(int)) |
| { |
| struct sigaction sa; |
| |
| sa.sa_handler = handler; |
| sa.sa_flags = 0; |
| sa.sa_mask = 0; |
| sa.sa_restorer = NULL; |
| return irqaction(irq,&sa); |
| } |
| |
| void free_irq(unsigned int irq) |
| { |
| struct sigaction * sa = irq + irq_sigaction; |
| unsigned long flags; |
| |
| if (irq > 15) { |
| printk("Trying to free IRQ%d\n",irq); |
| return; |
| } |
| if (!sa->sa_mask) { |
| printk("Trying to free free IRQ%d\n",irq); |
| return; |
| } |
| save_flags(flags); |
| cli(); |
| if (irq < 8) { |
| cache_21 |= 1 << irq; |
| outb(cache_21,0x21); |
| } else { |
| cache_A1 |= 1 << (irq-8); |
| outb(cache_A1,0xA1); |
| } |
| set_intr_gate(0x20+irq,bad_interrupt[irq]); |
| sa->sa_handler = NULL; |
| sa->sa_flags = 0; |
| sa->sa_mask = 0; |
| sa->sa_restorer = NULL; |
| restore_flags(flags); |
| } |
| |
| /* |
| * Note that on a 486, we don't want to do a SIGFPE on a irq13 |
| * as the irq is unreliable, and exception 16 works correctly |
| * (ie as explained in the intel litterature). 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 void math_error_irq(int cpl) |
| { |
| outb(0,0xF0); |
| if (ignore_irq13) |
| return; |
| math_error(); |
| } |
| |
| static void no_action(int cpl) { } |
| |
| static struct sigaction ignore_IRQ = { |
| no_action, |
| 0, |
| SA_INTERRUPT, |
| NULL |
| }; |
| |
| void init_IRQ(void) |
| { |
| int i; |
| |
| for (i = 0; i < 16 ; i++) |
| set_intr_gate(0x20+i,bad_interrupt[i]); |
| if (irqaction(2,&ignore_IRQ)) |
| printk("Unable to get IRQ2 for cascade\n"); |
| if (request_irq(13,math_error_irq)) |
| printk("Unable to get IRQ13 for math-error handler\n"); |
| |
| /* intialize the bottom half routines. */ |
| for (i = 0; i < 32; i++) { |
| bh_base[i].routine = NULL; |
| bh_base[i].data = NULL; |
| } |
| bh_active = 0; |
| intr_count = 0; |
| } |