text: /*
   *  arch/ppc/kernel/irq.c
   *
   *  Derived from arch/i386/kernel/irq.c
   *    Copyright (C) 1992 Linus Torvalds
   *  Adapted from arch/i386 by Gary Thomas
   *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
   *    Copyright (C) 1996-2001 Cort Dougan
   *  Adapted for Power Macintosh by Paul Mackerras
   *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
   *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   *
   * 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.
   *
   * The MPC8xx has an interrupt mask in the SIU.  If a bit is set, the
   * interrupt is _enabled_.  As expected, IRQ0 is bit 0 in the 32-bit
   * mask register (of which only 16 are defined), hence the weird shifting
   * and complement of the cached_irq_mask.  I want to be able to stuff
   * this right into the SIU SMASK register.
   * Many of the prep/chrp functions are conditional compiled on CONFIG_8xx
   * to reduce code space and undefined function references.
   */
  
  #include <linux/module.h>
  #include <linux/threads.h>
  #include <linux/kernel_stat.h>
  #include <linux/signal.h>
  #include <linux/sched.h>
  #include <linux/ptrace.h>
  #include <linux/ioport.h>
  #include <linux/interrupt.h>
  #include <linux/timex.h>
  #include <linux/config.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/delay.h>
  #include <linux/irq.h>
  #include <linux/seq_file.h>
  #include <linux/cpumask.h>
  #include <linux/profile.h>
  #include <linux/bitops.h>
  
  #include <asm/uaccess.h>
  #include <asm/system.h>
  #include <asm/io.h>
  #include <asm/pgtable.h>
  #include <asm/irq.h>
  #include <asm/cache.h>
  #include <asm/prom.h>
  #include <asm/ptrace.h>
  #include <asm/machdep.h>
  #ifdef CONFIG_PPC_ISERIES
  #include <asm/paca.h>
  #endif
  
  int __irq_offset_value;
  #ifdef CONFIG_PPC32
  EXPORT_SYMBOL(__irq_offset_value);
  #endif
  
  static int ppc_spurious_interrupts;
  
  #ifdef CONFIG_PPC32
  #define NR_MASK_WORDS	((NR_IRQS + 31) / 32)
  
  unsigned long ppc_cached_irq_mask[NR_MASK_WORDS];
  atomic_t ppc_n_lost_interrupts;
  
  #ifdef CONFIG_TAU_INT
  extern int tau_initialized;
  extern int tau_interrupts(int);
  #endif
  
  #if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
  extern atomic_t ipi_recv;
  extern atomic_t ipi_sent;
  #endif
  #endif /* CONFIG_PPC32 */
  
  #ifdef CONFIG_PPC64
  EXPORT_SYMBOL(irq_desc);
  
  int distribute_irqs = 1;
  u64 ppc64_interrupt_controller;
  #endif /* CONFIG_PPC64 */
  
  int show_interrupts(struct seq_file *p, void *v)
  {
  	int i = *(loff_t *)v, j;
  	struct irqaction *action;
  	irq_desc_t *desc;
  	unsigned long flags;
  
  	if (i == 0) {
  		seq_puts(p, "           ");
  		for_each_online_cpu(j)
  			seq_printf(p, "CPU%d       ", j);
  		seq_putc(p, '\n');
  	}
  
  	if (i < NR_IRQS) {
  		desc = get_irq_desc(i);
  		spin_lock_irqsave(&desc->lock, flags);
  		action = desc->action;
  		if (!action || !action->handler)
  			goto skip;
  		seq_printf(p, "%3d: ", i);
  #ifdef CONFIG_SMP
  		for_each_online_cpu(j)
  			seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  #else
  		seq_printf(p, "%10u ", kstat_irqs(i));
  #endif /* CONFIG_SMP */
  		if (desc->handler)
  			seq_printf(p, " %s ", desc->handler->typename);
  		else
  			seq_puts(p, "  None      ");
  		seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
  		seq_printf(p, "    %s", action->name);
  		for (action = action->next; action; action = action->next)
  			seq_printf(p, ", %s", action->name);
  		seq_putc(p, '\n');
  skip:
  		spin_unlock_irqrestore(&desc->lock, flags);
  	} else if (i == NR_IRQS) {
  #ifdef CONFIG_PPC32
  #ifdef CONFIG_TAU_INT
  		if (tau_initialized){
  			seq_puts(p, "TAU: ");
  			for (j = 0; j < NR_CPUS; j++)
  				if (cpu_online(j))
  					seq_printf(p, "%10u ", tau_interrupts(j));
  			seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
  		}
  #endif
  #if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
  		/* should this be per processor send/receive? */
  		seq_printf(p, "IPI (recv/sent): %10u/%u\n",
  				atomic_read(&ipi_recv), atomic_read(&ipi_sent));
  #endif
  #endif /* CONFIG_PPC32 */
  		seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
  	}
  	return 0;
  }
  
  #ifdef CONFIG_HOTPLUG_CPU
  void fixup_irqs(cpumask_t map)
  {
  	unsigned int irq;
  	static int warned;
  
  	for_each_irq(irq) {
  		cpumask_t mask;
  
  		if (irq_desc[irq].status & IRQ_PER_CPU)
  			continue;
  
  		cpus_and(mask, irq_affinity[irq], map);
  		if (any_online_cpu(mask) == NR_CPUS) {
  			printk("Breaking affinity for irq %i\n", irq);
  			mask = map;
  		}
  		if (irq_desc[irq].handler->set_affinity)
  			irq_desc[irq].handler->set_affinity(irq, mask);
  		else if (irq_desc[irq].action && !(warned++))
  			printk("Cannot set affinity for irq %i\n", irq);
  	}
  
  	local_irq_enable();
  	mdelay(1);
  	local_irq_disable();
  }
  #endif
  
  void do_IRQ(struct pt_regs *regs)
  {
  	int irq;
  #ifdef CONFIG_IRQSTACKS
  	struct thread_info *curtp, *irqtp;
  #endif
  
          irq_enter();
  
  #ifdef CONFIG_DEBUG_STACKOVERFLOW
  	/* Debugging check for stack overflow: is there less than 2KB free? */
  	{
  		long sp;
  
  		sp = __get_SP() & (THREAD_SIZE-1);
  
  		if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
  			printk("do_IRQ: stack overflow: %ld\n",
  				sp - sizeof(struct thread_info));
  			dump_stack();
  		}
  	}
  #endif
  
  	/*
  	 * Every platform is required to implement ppc_md.get_irq.
  	 * This function will either return an irq number or -1 to
  	 * indicate there are no more pending.
  	 * The value -2 is for buggy hardware and means that this IRQ
  	 * has already been handled. -- Tom
  	 */
  	irq = ppc_md.get_irq(regs);
  
  	if (irq >= 0) {
  #ifdef CONFIG_IRQSTACKS
  		/* Switch to the irq stack to handle this */
  		curtp = current_thread_info();
  		irqtp = hardirq_ctx[smp_processor_id()];
  		if (curtp != irqtp) {
  			irqtp->task = curtp->task;
  			irqtp->flags = 0;
  			call___do_IRQ(irq, regs, irqtp);
  			irqtp->task = NULL;
  			if (irqtp->flags)
  				set_bits(irqtp->flags, &curtp->flags);
  		} else
  #endif
  			__do_IRQ(irq, regs);
  	} else if (irq != -2)
  		/* That's not SMP safe ... but who cares ? */
  		ppc_spurious_interrupts++;
  
          irq_exit();
  
  #ifdef CONFIG_PPC_ISERIES
  	if (get_lppaca()->int_dword.fields.decr_int) {
  		get_lppaca()->int_dword.fields.decr_int = 0;
  		/* Signal a fake decrementer interrupt */
  		timer_interrupt(regs);
  	}
  #endif
  }
  
  void __init init_IRQ(void)
  {
  #ifdef CONFIG_PPC64
  	static int once = 0;
  
  	if (once)
  		return;
  
  	once++;
  
  #endif
  	ppc_md.init_IRQ();
  #ifdef CONFIG_PPC64
  	irq_ctx_init();
  #endif
  }
  
  #ifdef CONFIG_PPC64
  /*
   * Virtual IRQ mapping code, used on systems with XICS interrupt controllers.
   */
  
  #define UNDEFINED_IRQ 0xffffffff
  unsigned int virt_irq_to_real_map[NR_IRQS];
  
  /*
   * Don't use virtual irqs 0, 1, 2 for devices.
   * The pcnet32 driver considers interrupt numbers < 2 to be invalid,
   * and 2 is the XICS IPI interrupt.
   * We limit virtual irqs to 17 less than NR_IRQS so that when we
   * offset them by 16 (to reserve the first 16 for ISA interrupts)
   * we don't end up with an interrupt number >= NR_IRQS.
   */
  #define MIN_VIRT_IRQ	3
  #define MAX_VIRT_IRQ	(NR_IRQS - NUM_ISA_INTERRUPTS - 1)
  #define NR_VIRT_IRQS	(MAX_VIRT_IRQ - MIN_VIRT_IRQ + 1)
  
  void
  virt_irq_init(void)
  {
  	int i;
  	for (i = 0; i < NR_IRQS; i++)
  		virt_irq_to_real_map[i] = UNDEFINED_IRQ;
  }
  
  /* Create a mapping for a real_irq if it doesn't already exist.
   * Return the virtual irq as a convenience.
   */
  int virt_irq_create_mapping(unsigned int real_irq)
  {
  	unsigned int virq, first_virq;
  	static int warned;
  
  	if (ppc64_interrupt_controller == IC_OPEN_PIC)
  		return real_irq;	/* no mapping for openpic (for now) */
  
  	if (ppc64_interrupt_controller == IC_CELL_PIC)
  		return real_irq;	/* no mapping for iic either */
  
  	/* don't map interrupts < MIN_VIRT_IRQ */
  	if (real_irq < MIN_VIRT_IRQ) {
  		virt_irq_to_real_map[real_irq] = real_irq;
  		return real_irq;
  	}
  
  	/* map to a number between MIN_VIRT_IRQ and MAX_VIRT_IRQ */
  	virq = real_irq;
  	if (virq > MAX_VIRT_IRQ)
  		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;
  
  	/* search for this number or a free slot */
  	first_virq = virq;
  	while (virt_irq_to_real_map[virq] != UNDEFINED_IRQ) {
  		if (virt_irq_to_real_map[virq] == real_irq)
  			return virq;
  		if (++virq > MAX_VIRT_IRQ)
  			virq = MIN_VIRT_IRQ;
  		if (virq == first_virq)
  			goto nospace;	/* oops, no free slots */
  	}
  
  	virt_irq_to_real_map[virq] = real_irq;
  	return virq;
  
   nospace:
  	if (!warned) {
  		printk(KERN_CRIT "Interrupt table is full\n");
  		printk(KERN_CRIT "Increase NR_IRQS (currently %d) "
  		       "in your kernel sources and rebuild.\n", NR_IRQS);
  		warned = 1;
  	}
  	return NO_IRQ;
  }
  
  /*
   * In most cases will get a hit on the very first slot checked in the
   * virt_irq_to_real_map.  Only when there are a large number of
   * IRQs will this be expensive.
   */
  unsigned int real_irq_to_virt_slowpath(unsigned int real_irq)
  {
  	unsigned int virq;
  	unsigned int first_virq;
  
  	virq = real_irq;
  
  	if (virq > MAX_VIRT_IRQ)
  		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;
  
  	first_virq = virq;
  
  	do {
  		if (virt_irq_to_real_map[virq] == real_irq)
  			return virq;
  
  		virq++;
  
  		if (virq >= MAX_VIRT_IRQ)
  			virq = 0;
  
  	} while (first_virq != virq);
  
  	return NO_IRQ;
  
  }
  
  #ifdef CONFIG_IRQSTACKS
  struct thread_info *softirq_ctx[NR_CPUS];
  struct thread_info *hardirq_ctx[NR_CPUS];
  
  void irq_ctx_init(void)
  {
  	struct thread_info *tp;
  	int i;
  
  	for_each_cpu(i) {
  		memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
  		tp = softirq_ctx[i];
  		tp->cpu = i;
  		tp->preempt_count = SOFTIRQ_OFFSET;
  
  		memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
  		tp = hardirq_ctx[i];
  		tp->cpu = i;
  		tp->preempt_count = HARDIRQ_OFFSET;
  	}
  }
  
  void do_softirq(void)
  {
  	unsigned long flags;
  	struct thread_info *curtp, *irqtp;
  
  	if (in_interrupt())
  		return;
  
  	local_irq_save(flags);
  
  	if (local_softirq_pending()) {
  		curtp = current_thread_info();
  		irqtp = softirq_ctx[smp_processor_id()];
  		irqtp->task = curtp->task;
  		call_do_softirq(irqtp);
  		irqtp->task = NULL;
  	}
  
  	local_irq_restore(flags);
  }
  EXPORT_SYMBOL(do_softirq);
  
  #endif /* CONFIG_IRQSTACKS */
  
  static int __init setup_noirqdistrib(char *str)
  {
  	distribute_irqs = 0;
  	return 1;
  }
  
  __setup("noirqdistrib", setup_noirqdistrib);
  #endif /* CONFIG_PPC64 */
  