Merge HEAD from ../scsi-misc-2.6-old

[linux-2.6] / arch / i386 / mach-voyager / voyager_smp.c

/* -*- mode: c; c-basic-offset: 8 -*- */

/* Copyright (C) 1999,2001
 *
 * Author: J.E.J.Bottomley@HansenPartnership.com
 *
 * linux/arch/i386/kernel/voyager_smp.c
 *
 * This file provides all the same external entries as smp.c but uses
 * the voyager hal to provide the functionality
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>
#include <linux/mc146818rtc.h>
#include <linux/cache.h>
#include <linux/interrupt.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/bootmem.h>
#include <linux/completion.h>
#include <asm/desc.h>
#include <asm/voyager.h>
#include <asm/vic.h>
#include <asm/mtrr.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/arch_hooks.h>

/* TLB state -- visible externally, indexed physically */
DEFINE_PER_CPU(struct tlb_state, cpu_tlbstate) ____cacheline_aligned = { &init_mm, 0 };

/* CPU IRQ affinity -- set to all ones initially */
static unsigned long cpu_irq_affinity[NR_CPUS] __cacheline_aligned = { [0 ... NR_CPUS-1]  = ~0UL };

/* per CPU data structure (for /proc/cpuinfo et al), visible externally
 * indexed physically */
struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned;
EXPORT_SYMBOL(cpu_data);

/* physical ID of the CPU used to boot the system */
unsigned char boot_cpu_id;

/* The memory line addresses for the Quad CPIs */
struct voyager_qic_cpi *voyager_quad_cpi_addr[NR_CPUS] __cacheline_aligned;

/* The masks for the Extended VIC processors, filled in by cat_init */
__u32 voyager_extended_vic_processors = 0;

/* Masks for the extended Quad processors which cannot be VIC booted */
__u32 voyager_allowed_boot_processors = 0;

/* The mask for the Quad Processors (both extended and non-extended) */
__u32 voyager_quad_processors = 0;

/* Total count of live CPUs, used in process.c to display
 * the CPU information and in irq.c for the per CPU irq
 * activity count.  Finally exported by i386_ksyms.c */
static int voyager_extended_cpus = 1;

/* Have we found an SMP box - used by time.c to do the profiling
   interrupt for timeslicing; do not set to 1 until the per CPU timer
   interrupt is active */
int smp_found_config = 0;

/* Used for the invalidate map that's also checked in the spinlock */
static volatile unsigned long smp_invalidate_needed;

/* Bitmask of currently online CPUs - used by setup.c for
   /proc/cpuinfo, visible externally but still physical */
cpumask_t cpu_online_map = CPU_MASK_NONE;
EXPORT_SYMBOL(cpu_online_map);

/* Bitmask of CPUs present in the system - exported by i386_syms.c, used
 * by scheduler but indexed physically */
cpumask_t phys_cpu_present_map = CPU_MASK_NONE;


/* The internal functions */
static void send_CPI(__u32 cpuset, __u8 cpi);
static void ack_CPI(__u8 cpi);
static int ack_QIC_CPI(__u8 cpi);
static void ack_special_QIC_CPI(__u8 cpi);
static void ack_VIC_CPI(__u8 cpi);
static void send_CPI_allbutself(__u8 cpi);
static void enable_vic_irq(unsigned int irq);
static void disable_vic_irq(unsigned int irq);
static unsigned int startup_vic_irq(unsigned int irq);
static void enable_local_vic_irq(unsigned int irq);
static void disable_local_vic_irq(unsigned int irq);
static void before_handle_vic_irq(unsigned int irq);
static void after_handle_vic_irq(unsigned int irq);
static void set_vic_irq_affinity(unsigned int irq, cpumask_t mask);
static void ack_vic_irq(unsigned int irq);
static void vic_enable_cpi(void);
static void do_boot_cpu(__u8 cpuid);
static void do_quad_bootstrap(void);

int hard_smp_processor_id(void);

/* Inline functions */
static inline void
send_one_QIC_CPI(__u8 cpu, __u8 cpi)
{
        voyager_quad_cpi_addr[cpu]->qic_cpi[cpi].cpi =
                (smp_processor_id() << 16) + cpi;
}

static inline void
send_QIC_CPI(__u32 cpuset, __u8 cpi)
{
        int cpu;

        for_each_online_cpu(cpu) {
                if(cpuset & (1<<cpu)) {
#ifdef VOYAGER_DEBUG
                        if(!cpu_isset(cpu, cpu_online_map))
                                VDEBUG(("CPU%d sending cpi %d to CPU%d not in cpu_online_map\n", hard_smp_processor_id(), cpi, cpu));
#endif
                        send_one_QIC_CPI(cpu, cpi - QIC_CPI_OFFSET);
                }
        }
}

static inline void
wrapper_smp_local_timer_interrupt(struct pt_regs *regs)
{
        irq_enter();
        smp_local_timer_interrupt(regs);
        irq_exit();
}

static inline void
send_one_CPI(__u8 cpu, __u8 cpi)
{
        if(voyager_quad_processors & (1<<cpu))
                send_one_QIC_CPI(cpu, cpi - QIC_CPI_OFFSET);
        else
                send_CPI(1<<cpu, cpi);
}

static inline void
send_CPI_allbutself(__u8 cpi)
{
        __u8 cpu = smp_processor_id();
        __u32 mask = cpus_addr(cpu_online_map)[0] & ~(1 << cpu);
        send_CPI(mask, cpi);
}

static inline int
is_cpu_quad(void)
{
        __u8 cpumask = inb(VIC_PROC_WHO_AM_I);
        return ((cpumask & QUAD_IDENTIFIER) == QUAD_IDENTIFIER);
}

static inline int
is_cpu_extended(void)
{
        __u8 cpu = hard_smp_processor_id();

        return(voyager_extended_vic_processors & (1<<cpu));
}

static inline int
is_cpu_vic_boot(void)
{
        __u8 cpu = hard_smp_processor_id();

        return(voyager_extended_vic_processors
               & voyager_allowed_boot_processors & (1<<cpu));
}


static inline void
ack_CPI(__u8 cpi)
{
        switch(cpi) {
        case VIC_CPU_BOOT_CPI:
                if(is_cpu_quad() && !is_cpu_vic_boot())
                        ack_QIC_CPI(cpi);
                else
                        ack_VIC_CPI(cpi);
                break;
        case VIC_SYS_INT:
        case VIC_CMN_INT: 
                /* These are slightly strange.  Even on the Quad card,
                 * They are vectored as VIC CPIs */
                if(is_cpu_quad())
                        ack_special_QIC_CPI(cpi);
                else
                        ack_VIC_CPI(cpi);
                break;
        default:
                printk("VOYAGER ERROR: CPI%d is in common CPI code\n", cpi);
                break;
        }
}

/* local variables */

/* The VIC IRQ descriptors -- these look almost identical to the
 * 8259 IRQs except that masks and things must be kept per processor
 */
static struct hw_interrupt_type vic_irq_type = {
        .typename = "VIC-level",
        .startup = startup_vic_irq,
        .shutdown = disable_vic_irq,
        .enable = enable_vic_irq,
        .disable = disable_vic_irq,
        .ack = before_handle_vic_irq,
        .end = after_handle_vic_irq,
        .set_affinity = set_vic_irq_affinity,
};

/* used to count up as CPUs are brought on line (starts at 0) */
static int cpucount = 0;

/* steal a page from the bottom of memory for the trampoline and
 * squirrel its address away here.  This will be in kernel virtual
 * space */
static __u32 trampoline_base;

/* The per cpu profile stuff - used in smp_local_timer_interrupt */
static DEFINE_PER_CPU(int, prof_multiplier) = 1;
static DEFINE_PER_CPU(int, prof_old_multiplier) = 1;
static DEFINE_PER_CPU(int, prof_counter) =  1;

/* the map used to check if a CPU has booted */
static __u32 cpu_booted_map;

/* the synchronize flag used to hold all secondary CPUs spinning in
 * a tight loop until the boot sequence is ready for them */
static cpumask_t smp_commenced_mask = CPU_MASK_NONE;

/* This is for the new dynamic CPU boot code */
cpumask_t cpu_callin_map = CPU_MASK_NONE;
cpumask_t cpu_callout_map = CPU_MASK_NONE;
EXPORT_SYMBOL(cpu_callout_map);
cpumask_t cpu_possible_map = CPU_MASK_ALL;
EXPORT_SYMBOL(cpu_possible_map);

/* The per processor IRQ masks (these are usually kept in sync) */
static __u16 vic_irq_mask[NR_CPUS] __cacheline_aligned;

/* the list of IRQs to be enabled by the VIC_ENABLE_IRQ_CPI */
static __u16 vic_irq_enable_mask[NR_CPUS] __cacheline_aligned = { 0 };

/* Lock for enable/disable of VIC interrupts */
static  __cacheline_aligned DEFINE_SPINLOCK(vic_irq_lock);

/* The boot processor is correctly set up in PC mode when it 
 * comes up, but the secondaries need their master/slave 8259
 * pairs initializing correctly */

/* Interrupt counters (per cpu) and total - used to try to
 * even up the interrupt handling routines */
static long vic_intr_total = 0;
static long vic_intr_count[NR_CPUS] __cacheline_aligned = { 0 };
static unsigned long vic_tick[NR_CPUS] __cacheline_aligned = { 0 };

/* Since we can only use CPI0, we fake all the other CPIs */
static unsigned long vic_cpi_mailbox[NR_CPUS] __cacheline_aligned;

/* debugging routine to read the isr of the cpu's pic */
static inline __u16
vic_read_isr(void)
{
        __u16 isr;

        outb(0x0b, 0xa0);
        isr = inb(0xa0) << 8;
        outb(0x0b, 0x20);
        isr |= inb(0x20);

        return isr;
}

static __init void
qic_setup(void)
{
        if(!is_cpu_quad()) {
                /* not a quad, no setup */
                return;
        }
        outb(QIC_DEFAULT_MASK0, QIC_MASK_REGISTER0);
        outb(QIC_CPI_ENABLE, QIC_MASK_REGISTER1);
        
        if(is_cpu_extended()) {
                /* the QIC duplicate of the VIC base register */
                outb(VIC_DEFAULT_CPI_BASE, QIC_VIC_CPI_BASE_REGISTER);
                outb(QIC_DEFAULT_CPI_BASE, QIC_CPI_BASE_REGISTER);

                /* FIXME: should set up the QIC timer and memory parity
                 * error vectors here */
        }
}

static __init void
vic_setup_pic(void)
{
        outb(1, VIC_REDIRECT_REGISTER_1);
        /* clear the claim registers for dynamic routing */
        outb(0, VIC_CLAIM_REGISTER_0);
        outb(0, VIC_CLAIM_REGISTER_1);

        outb(0, VIC_PRIORITY_REGISTER);
        /* Set the Primary and Secondary Microchannel vector
         * bases to be the same as the ordinary interrupts
         *
         * FIXME: This would be more efficient using separate
         * vectors. */
        outb(FIRST_EXTERNAL_VECTOR, VIC_PRIMARY_MC_BASE);
        outb(FIRST_EXTERNAL_VECTOR, VIC_SECONDARY_MC_BASE);
        /* Now initiallise the master PIC belonging to this CPU by
         * sending the four ICWs */

        /* ICW1: level triggered, ICW4 needed */
        outb(0x19, 0x20);

        /* ICW2: vector base */
        outb(FIRST_EXTERNAL_VECTOR, 0x21);

        /* ICW3: slave at line 2 */
        outb(0x04, 0x21);

        /* ICW4: 8086 mode */
        outb(0x01, 0x21);

        /* now the same for the slave PIC */

        /* ICW1: level trigger, ICW4 needed */
        outb(0x19, 0xA0);

        /* ICW2: slave vector base */
        outb(FIRST_EXTERNAL_VECTOR + 8, 0xA1);
        
        /* ICW3: slave ID */
        outb(0x02, 0xA1);

        /* ICW4: 8086 mode */
        outb(0x01, 0xA1);
}

static void
do_quad_bootstrap(void)
{
        if(is_cpu_quad() && is_cpu_vic_boot()) {
                int i;
                unsigned long flags;
                __u8 cpuid = hard_smp_processor_id();

                local_irq_save(flags);

                for(i = 0; i<4; i++) {
                        /* FIXME: this would be >>3 &0x7 on the 32 way */
                        if(((cpuid >> 2) & 0x03) == i)
                                /* don't lower our own mask! */
                                continue;

                        /* masquerade as local Quad CPU */
                        outb(QIC_CPUID_ENABLE | i, QIC_PROCESSOR_ID);
                        /* enable the startup CPI */
                        outb(QIC_BOOT_CPI_MASK, QIC_MASK_REGISTER1);
                        /* restore cpu id */
                        outb(0, QIC_PROCESSOR_ID);
                }
                local_irq_restore(flags);
        }
}


/* Set up all the basic stuff: read the SMP config and make all the
 * SMP information reflect only the boot cpu.  All others will be
 * brought on-line later. */
void __init 
find_smp_config(void)
{
        int i;

        boot_cpu_id = hard_smp_processor_id();

        printk("VOYAGER SMP: Boot cpu is %d\n", boot_cpu_id);

        /* initialize the CPU structures (moved from smp_boot_cpus) */
        for(i=0; i<NR_CPUS; i++) {
                cpu_irq_affinity[i] = ~0;
        }
        cpu_online_map = cpumask_of_cpu(boot_cpu_id);

        /* The boot CPU must be extended */
        voyager_extended_vic_processors = 1<<boot_cpu_id;
        /* initially, all of the first 8 cpu's can boot */
        voyager_allowed_boot_processors = 0xff;
        /* set up everything for just this CPU, we can alter
         * this as we start the other CPUs later */
        /* now get the CPU disposition from the extended CMOS */
        cpus_addr(phys_cpu_present_map)[0] = voyager_extended_cmos_read(VOYAGER_PROCESSOR_PRESENT_MASK);
        cpus_addr(phys_cpu_present_map)[0] |= voyager_extended_cmos_read(VOYAGER_PROCESSOR_PRESENT_MASK + 1) << 8;
        cpus_addr(phys_cpu_present_map)[0] |= voyager_extended_cmos_read(VOYAGER_PROCESSOR_PRESENT_MASK + 2) << 16;
        cpus_addr(phys_cpu_present_map)[0] |= voyager_extended_cmos_read(VOYAGER_PROCESSOR_PRESENT_MASK + 3) << 24;
        printk("VOYAGER SMP: phys_cpu_present_map = 0x%lx\n", cpus_addr(phys_cpu_present_map)[0]);
        /* Here we set up the VIC to enable SMP */
        /* enable the CPIs by writing the base vector to their register */
        outb(VIC_DEFAULT_CPI_BASE, VIC_CPI_BASE_REGISTER);
        outb(1, VIC_REDIRECT_REGISTER_1);
        /* set the claim registers for static routing --- Boot CPU gets
         * all interrupts untill all other CPUs started */
        outb(0xff, VIC_CLAIM_REGISTER_0);
        outb(0xff, VIC_CLAIM_REGISTER_1);
        /* Set the Primary and Secondary Microchannel vector
         * bases to be the same as the ordinary interrupts
         *
         * FIXME: This would be more efficient using separate
         * vectors. */
        outb(FIRST_EXTERNAL_VECTOR, VIC_PRIMARY_MC_BASE);
        outb(FIRST_EXTERNAL_VECTOR, VIC_SECONDARY_MC_BASE);

        /* Finally tell the firmware that we're driving */
        outb(inb(VOYAGER_SUS_IN_CONTROL_PORT) | VOYAGER_IN_CONTROL_FLAG,
             VOYAGER_SUS_IN_CONTROL_PORT);

        current_thread_info()->cpu = boot_cpu_id;
}

/*
 *      The bootstrap kernel entry code has set these up. Save them
 *      for a given CPU, id is physical */
void __init
smp_store_cpu_info(int id)
{
        struct cpuinfo_x86 *c=&cpu_data[id];

        *c = boot_cpu_data;

        identify_cpu(c);
}

/* set up the trampoline and return the physical address of the code */
static __u32 __init
setup_trampoline(void)
{
        /* these two are global symbols in trampoline.S */
        extern __u8 trampoline_end[];
        extern __u8 trampoline_data[];

        memcpy((__u8 *)trampoline_base, trampoline_data,
               trampoline_end - trampoline_data);
        return virt_to_phys((__u8 *)trampoline_base);
}

/* Routine initially called when a non-boot CPU is brought online */
static void __init
start_secondary(void *unused)
{
        __u8 cpuid = hard_smp_processor_id();
        /* external functions not defined in the headers */
        extern void calibrate_delay(void);

        cpu_init();

        /* OK, we're in the routine */
        ack_CPI(VIC_CPU_BOOT_CPI);

        /* setup the 8259 master slave pair belonging to this CPU ---
         * we won't actually receive any until the boot CPU
         * relinquishes it's static routing mask */
        vic_setup_pic();

        qic_setup();

        if(is_cpu_quad() && !is_cpu_vic_boot()) {
                /* clear the boot CPI */
                __u8 dummy;

                dummy = voyager_quad_cpi_addr[cpuid]->qic_cpi[VIC_CPU_BOOT_CPI].cpi;
                printk("read dummy %d\n", dummy);
        }

        /* lower the mask to receive CPIs */
        vic_enable_cpi();

        VDEBUG(("VOYAGER SMP: CPU%d, stack at about %p\n", cpuid, &cpuid));

        /* enable interrupts */
        local_irq_enable();

        /* get our bogomips */
        calibrate_delay();

        /* save our processor parameters */
        smp_store_cpu_info(cpuid);

        /* if we're a quad, we may need to bootstrap other CPUs */
        do_quad_bootstrap();

        /* FIXME: this is rather a poor hack to prevent the CPU
         * activating softirqs while it's supposed to be waiting for
         * permission to proceed.  Without this, the new per CPU stuff
         * in the softirqs will fail */
        local_irq_disable();
        cpu_set(cpuid, cpu_callin_map);

        /* signal that we're done */
        cpu_booted_map = 1;

        while (!cpu_isset(cpuid, smp_commenced_mask))
                rep_nop();
        local_irq_enable();

        local_flush_tlb();

        cpu_set(cpuid, cpu_online_map);
        wmb();
        cpu_idle();
}


/* Routine to kick start the given CPU and wait for it to report ready
 * (or timeout in startup).  When this routine returns, the requested
 * CPU is either fully running and configured or known to be dead.
 *
 * We call this routine sequentially 1 CPU at a time, so no need for
 * locking */

static void __init
do_boot_cpu(__u8 cpu)
{
        struct task_struct *idle;
        int timeout;
        unsigned long flags;
        int quad_boot = (1<<cpu) & voyager_quad_processors 
                & ~( voyager_extended_vic_processors
                     & voyager_allowed_boot_processors);

        /* For the 486, we can't use the 4Mb page table trick, so
         * must map a region of memory */
#ifdef CONFIG_M486
        int i;
        unsigned long *page_table_copies = (unsigned long *)
                __get_free_page(GFP_KERNEL);
#endif
        pgd_t orig_swapper_pg_dir0;

        /* This is an area in head.S which was used to set up the
         * initial kernel stack.  We need to alter this to give the
         * booting CPU a new stack (taken from its idle process) */
        extern struct {
                __u8 *esp;
                unsigned short ss;
        } stack_start;
        /* This is the format of the CPI IDT gate (in real mode) which
         * we're hijacking to boot the CPU */
        union   IDTFormat {
                struct seg {
                        __u16   Offset;
                        __u16   Segment;
                } idt;
                __u32 val;
        } hijack_source;

        __u32 *hijack_vector;
        __u32 start_phys_address = setup_trampoline();

        /* There's a clever trick to this: The linux trampoline is
         * compiled to begin at absolute location zero, so make the
         * address zero but have the data segment selector compensate
         * for the actual address */
        hijack_source.idt.Offset = start_phys_address & 0x000F;
        hijack_source.idt.Segment = (start_phys_address >> 4) & 0xFFFF;

        cpucount++;
        idle = fork_idle(cpu);
        if(IS_ERR(idle))
                panic("failed fork for CPU%d", cpu);
        idle->thread.eip = (unsigned long) start_secondary;
        /* init_tasks (in sched.c) is indexed logically */
        stack_start.esp = (void *) idle->thread.esp;

        irq_ctx_init(cpu);

        /* Note: Don't modify initial ss override */
        VDEBUG(("VOYAGER SMP: Booting CPU%d at 0x%lx[%x:%x], stack %p\n", cpu, 
                (unsigned long)hijack_source.val, hijack_source.idt.Segment,
                hijack_source.idt.Offset, stack_start.esp));
        /* set the original swapper_pg_dir[0] to map 0 to 4Mb transparently
         * (so that the booting CPU can find start_32 */
        orig_swapper_pg_dir0 = swapper_pg_dir[0];
#ifdef CONFIG_M486
        if(page_table_copies == NULL)
                panic("No free memory for 486 page tables\n");
        for(i = 0; i < PAGE_SIZE/sizeof(unsigned long); i++)
                page_table_copies[i] = (i * PAGE_SIZE) 
                        | _PAGE_RW | _PAGE_USER | _PAGE_PRESENT;

        ((unsigned long *)swapper_pg_dir)[0] = 
                ((virt_to_phys(page_table_copies)) & PAGE_MASK)
                | _PAGE_RW | _PAGE_USER | _PAGE_PRESENT;
#else
        ((unsigned long *)swapper_pg_dir)[0] = 
                (virt_to_phys(pg0) & PAGE_MASK)
                | _PAGE_RW | _PAGE_USER | _PAGE_PRESENT;
#endif

        if(quad_boot) {
                printk("CPU %d: non extended Quad boot\n", cpu);
                hijack_vector = (__u32 *)phys_to_virt((VIC_CPU_BOOT_CPI + QIC_DEFAULT_CPI_BASE)*4);
                *hijack_vector = hijack_source.val;
        } else {
                printk("CPU%d: extended VIC boot\n", cpu);
                hijack_vector = (__u32 *)phys_to_virt((VIC_CPU_BOOT_CPI + VIC_DEFAULT_CPI_BASE)*4);
                *hijack_vector = hijack_source.val;
                /* VIC errata, may also receive interrupt at this address */
                hijack_vector = (__u32 *)phys_to_virt((VIC_CPU_BOOT_ERRATA_CPI + VIC_DEFAULT_CPI_BASE)*4);
                *hijack_vector = hijack_source.val;
        }
        /* All non-boot CPUs start with interrupts fully masked.  Need
         * to lower the mask of the CPI we're about to send.  We do
         * this in the VIC by masquerading as the processor we're
         * about to boot and lowering its interrupt mask */
        local_irq_save(flags);
        if(quad_boot) {
                send_one_QIC_CPI(cpu, VIC_CPU_BOOT_CPI);
        } else {
                outb(VIC_CPU_MASQUERADE_ENABLE | cpu, VIC_PROCESSOR_ID);
                /* here we're altering registers belonging to `cpu' */
                
                outb(VIC_BOOT_INTERRUPT_MASK, 0x21);
                /* now go back to our original identity */
                outb(boot_cpu_id, VIC_PROCESSOR_ID);

                /* and boot the CPU */

                send_CPI((1<<cpu), VIC_CPU_BOOT_CPI);
        }
        cpu_booted_map = 0;
        local_irq_restore(flags);

        /* now wait for it to become ready (or timeout) */
        for(timeout = 0; timeout < 50000; timeout++) {
                if(cpu_booted_map)
                        break;
                udelay(100);
        }
        /* reset the page table */
        swapper_pg_dir[0] = orig_swapper_pg_dir0;
        local_flush_tlb();
#ifdef CONFIG_M486
        free_page((unsigned long)page_table_copies);
#endif
          
        if (cpu_booted_map) {
                VDEBUG(("CPU%d: Booted successfully, back in CPU %d\n",
                        cpu, smp_processor_id()));
        
                printk("CPU%d: ", cpu);
                print_cpu_info(&cpu_data[cpu]);
                wmb();
                cpu_set(cpu, cpu_callout_map);
        }
        else {
                printk("CPU%d FAILED TO BOOT: ", cpu);
                if (*((volatile unsigned char *)phys_to_virt(start_phys_address))==0xA5)
                        printk("Stuck.\n");
                else
                        printk("Not responding.\n");
                
                cpucount--;
        }
}

void __init
smp_boot_cpus(void)
{
        int i;

        /* CAT BUS initialisation must be done after the memory */
        /* FIXME: The L4 has a catbus too, it just needs to be
         * accessed in a totally different way */
        if(voyager_level == 5) {
                voyager_cat_init();

                /* now that the cat has probed the Voyager System Bus, sanity
                 * check the cpu map */
                if( ((voyager_quad_processors | voyager_extended_vic_processors)
                     & cpus_addr(phys_cpu_present_map)[0]) != cpus_addr(phys_cpu_present_map)[0]) {
                        /* should panic */
                        printk("\n\n***WARNING*** Sanity check of CPU present map FAILED\n");
                }
        } else if(voyager_level == 4)
                voyager_extended_vic_processors = cpus_addr(phys_cpu_present_map)[0];

        /* this sets up the idle task to run on the current cpu */
        voyager_extended_cpus = 1;
        /* Remove the global_irq_holder setting, it triggers a BUG() on
         * schedule at the moment */
        //global_irq_holder = boot_cpu_id;

        /* FIXME: Need to do something about this but currently only works
         * on CPUs with a tsc which none of mine have. 
        smp_tune_scheduling();
         */
        smp_store_cpu_info(boot_cpu_id);
        printk("CPU%d: ", boot_cpu_id);
        print_cpu_info(&cpu_data[boot_cpu_id]);

        if(is_cpu_quad()) {
                /* booting on a Quad CPU */
                printk("VOYAGER SMP: Boot CPU is Quad\n");
                qic_setup();
                do_quad_bootstrap();
        }

        /* enable our own CPIs */
        vic_enable_cpi();

        cpu_set(boot_cpu_id, cpu_online_map);
        cpu_set(boot_cpu_id, cpu_callout_map);
        
        /* loop over all the extended VIC CPUs and boot them.  The 
         * Quad CPUs must be bootstrapped by their extended VIC cpu */
        for(i = 0; i < NR_CPUS; i++) {
                if(i == boot_cpu_id || !cpu_isset(i, phys_cpu_present_map))
                        continue;
                do_boot_cpu(i);
                /* This udelay seems to be needed for the Quad boots
                 * don't remove unless you know what you're doing */
                udelay(1000);
        }
        /* we could compute the total bogomips here, but why bother?,
         * Code added from smpboot.c */
        {
                unsigned long bogosum = 0;
                for (i = 0; i < NR_CPUS; i++)
                        if (cpu_isset(i, cpu_online_map))
                                bogosum += cpu_data[i].loops_per_jiffy;
                printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
                        cpucount+1,
                        bogosum/(500000/HZ),
                        (bogosum/(5000/HZ))%100);
        }
        voyager_extended_cpus = hweight32(voyager_extended_vic_processors);
        printk("VOYAGER: Extended (interrupt handling CPUs): %d, non-extended: %d\n", voyager_extended_cpus, num_booting_cpus() - voyager_extended_cpus);
        /* that's it, switch to symmetric mode */
        outb(0, VIC_PRIORITY_REGISTER);
        outb(0, VIC_CLAIM_REGISTER_0);
        outb(0, VIC_CLAIM_REGISTER_1);
        
        VDEBUG(("VOYAGER SMP: Booted with %d CPUs\n", num_booting_cpus()));
}

/* Reload the secondary CPUs task structure (this function does not
 * return ) */
void __init 
initialize_secondary(void)
{
#if 0
        // AC kernels only
        set_current(hard_get_current());
#endif

        /*
         * We don't actually need to load the full TSS,
         * basically just the stack pointer and the eip.
         */

        asm volatile(
                "movl %0,%%esp\n\t"
                "jmp *%1"
                :
                :"r" (current->thread.esp),"r" (current->thread.eip));
}

/* handle a Voyager SYS_INT -- If we don't, the base board will
 * panic the system.
 *
 * System interrupts occur because some problem was detected on the
 * various busses.  To find out what you have to probe all the
 * hardware via the CAT bus.  FIXME: At the moment we do nothing. */
fastcall void
smp_vic_sys_interrupt(struct pt_regs *regs)
{
        ack_CPI(VIC_SYS_INT);
        printk("Voyager SYSTEM INTERRUPT\n");
}

/* Handle a voyager CMN_INT; These interrupts occur either because of
 * a system status change or because a single bit memory error
 * occurred.  FIXME: At the moment, ignore all this. */
fastcall void
smp_vic_cmn_interrupt(struct pt_regs *regs)
{
        static __u8 in_cmn_int = 0;
        static DEFINE_SPINLOCK(cmn_int_lock);

        /* common ints are broadcast, so make sure we only do this once */
        _raw_spin_lock(&cmn_int_lock);
        if(in_cmn_int)
                goto unlock_end;

        in_cmn_int++;
        _raw_spin_unlock(&cmn_int_lock);

        VDEBUG(("Voyager COMMON INTERRUPT\n"));

        if(voyager_level == 5)
                voyager_cat_do_common_interrupt();

        _raw_spin_lock(&cmn_int_lock);
        in_cmn_int = 0;
 unlock_end:
        _raw_spin_unlock(&cmn_int_lock);
        ack_CPI(VIC_CMN_INT);
}

/*
 * Reschedule call back. Nothing to do, all the work is done
 * automatically when we return from the interrupt.  */
static void
smp_reschedule_interrupt(void)
{
        /* do nothing */
}

static struct mm_struct * flush_mm;
static unsigned long flush_va;
static DEFINE_SPINLOCK(tlbstate_lock);
#define FLUSH_ALL       0xffffffff

/*
 * We cannot call mmdrop() because we are in interrupt context, 
 * instead update mm->cpu_vm_mask.
 *
 * We need to reload %cr3 since the page tables may be going
 * away from under us..
 */
static inline void
leave_mm (unsigned long cpu)
{
        if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
                BUG();
        cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).active_mm->cpu_vm_mask);
        load_cr3(swapper_pg_dir);
}


/*
 * Invalidate call-back
 */
static void 
smp_invalidate_interrupt(void)
{
        __u8 cpu = smp_processor_id();

        if (!test_bit(cpu, &smp_invalidate_needed))
                return;
        /* This will flood messages.  Don't uncomment unless you see
         * Problems with cross cpu invalidation
        VDEBUG(("VOYAGER SMP: CPU%d received INVALIDATE_CPI\n",
                smp_processor_id()));
        */

        if (flush_mm == per_cpu(cpu_tlbstate, cpu).active_mm) {
                if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK) {
                        if (flush_va == FLUSH_ALL)
                                local_flush_tlb();
                        else
                                __flush_tlb_one(flush_va);
                } else
                        leave_mm(cpu);
        }
        smp_mb__before_clear_bit();
        clear_bit(cpu, &smp_invalidate_needed);
        smp_mb__after_clear_bit();
}

/* All the new flush operations for 2.4 */


/* This routine is called with a physical cpu mask */
static void
flush_tlb_others (unsigned long cpumask, struct mm_struct *mm,
                                                unsigned long va)
{
        int stuck = 50000;

        if (!cpumask)
                BUG();
        if ((cpumask & cpus_addr(cpu_online_map)[0]) != cpumask)
                BUG();
        if (cpumask & (1 << smp_processor_id()))
                BUG();
        if (!mm)
                BUG();

        spin_lock(&tlbstate_lock);
        
        flush_mm = mm;
        flush_va = va;
        atomic_set_mask(cpumask, &smp_invalidate_needed);
        /*
         * We have to send the CPI only to
         * CPUs affected.
         */
        send_CPI(cpumask, VIC_INVALIDATE_CPI);

        while (smp_invalidate_needed) {
                mb();
                if(--stuck == 0) {
                        printk("***WARNING*** Stuck doing invalidate CPI (CPU%d)\n", smp_processor_id());
                        break;
                }
        }

        /* Uncomment only to debug invalidation problems
        VDEBUG(("VOYAGER SMP: Completed invalidate CPI (CPU%d)\n", cpu));
        */

        flush_mm = NULL;
        flush_va = 0;
        spin_unlock(&tlbstate_lock);
}

void
flush_tlb_current_task(void)
{
        struct mm_struct *mm = current->mm;
        unsigned long cpu_mask;

        preempt_disable();

        cpu_mask = cpus_addr(mm->cpu_vm_mask)[0] & ~(1 << smp_processor_id());
        local_flush_tlb();
        if (cpu_mask)
                flush_tlb_others(cpu_mask, mm, FLUSH_ALL);

        preempt_enable();
}


void
flush_tlb_mm (struct mm_struct * mm)
{
        unsigned long cpu_mask;

        preempt_disable();

        cpu_mask = cpus_addr(mm->cpu_vm_mask)[0] & ~(1 << smp_processor_id());

        if (current->active_mm == mm) {
                if (current->mm)
                        local_flush_tlb();
                else
                        leave_mm(smp_processor_id());
        }
        if (cpu_mask)
                flush_tlb_others(cpu_mask, mm, FLUSH_ALL);

        preempt_enable();
}

void flush_tlb_page(struct vm_area_struct * vma, unsigned long va)
{
        struct mm_struct *mm = vma->vm_mm;
        unsigned long cpu_mask;

        preempt_disable();

        cpu_mask = cpus_addr(mm->cpu_vm_mask)[0] & ~(1 << smp_processor_id());
        if (current->active_mm == mm) {
                if(current->mm)
                        __flush_tlb_one(va);
                 else
                        leave_mm(smp_processor_id());
        }

        if (cpu_mask)
                flush_tlb_others(cpu_mask, mm, va);

        preempt_enable();
}
EXPORT_SYMBOL(flush_tlb_page);

/* enable the requested IRQs */
static void
smp_enable_irq_interrupt(void)
{
        __u8 irq;
        __u8 cpu = get_cpu();

        VDEBUG(("VOYAGER SMP: CPU%d enabling irq mask 0x%x\n", cpu,
               vic_irq_enable_mask[cpu]));

        spin_lock(&vic_irq_lock);
        for(irq = 0; irq < 16; irq++) {
                if(vic_irq_enable_mask[cpu] & (1<<irq))
                        enable_local_vic_irq(irq);
        }
        vic_irq_enable_mask[cpu] = 0;
        spin_unlock(&vic_irq_lock);

        put_cpu_no_resched();
}
        
/*
 *      CPU halt call-back
 */
static void
smp_stop_cpu_function(void *dummy)
{
        VDEBUG(("VOYAGER SMP: CPU%d is STOPPING\n", smp_processor_id()));
        cpu_clear(smp_processor_id(), cpu_online_map);
        local_irq_disable();
        for(;;)
                halt();
}

static DEFINE_SPINLOCK(call_lock);

struct call_data_struct {
        void (*func) (void *info);
        void *info;
        volatile unsigned long started;
        volatile unsigned long finished;
        int wait;
};

static struct call_data_struct * call_data;

/* execute a thread on a new CPU.  The function to be called must be
 * previously set up.  This is used to schedule a function for
 * execution on all CPU's - set up the function then broadcast a
 * function_interrupt CPI to come here on each CPU */
static void
smp_call_function_interrupt(void)
{
        void (*func) (void *info) = call_data->func;
        void *info = call_data->info;
        /* must take copy of wait because call_data may be replaced
         * unless the function is waiting for us to finish */
        int wait = call_data->wait;
        __u8 cpu = smp_processor_id();

        /*
         * Notify initiating CPU that I've grabbed the data and am
         * about to execute the function
         */
        mb();
        if(!test_and_clear_bit(cpu, &call_data->started)) {
                /* If the bit wasn't set, this could be a replay */
                printk(KERN_WARNING "VOYAGER SMP: CPU %d received call funtion with no call pending\n", cpu);
                return;
        }
        /*
         * At this point the info structure may be out of scope unless wait==1
         */
        irq_enter();
        (*func)(info);
        irq_exit();
        if (wait) {
                mb();
                clear_bit(cpu, &call_data->finished);
        }
}

/* Call this function on all CPUs using the function_interrupt above 
    <func> The function to run. This must be fast and non-blocking.
    <info> An arbitrary pointer to pass to the function.
    <retry> If true, keep retrying until ready.
    <wait> If true, wait until function has completed on other CPUs.
    [RETURNS] 0 on success, else a negative status code. Does not return until
    remote CPUs are nearly ready to execute <<func>> or are or have executed.
*/
int
smp_call_function (void (*func) (void *info), void *info, int retry,
                   int wait)
{
        struct call_data_struct data;
        __u32 mask = cpus_addr(cpu_online_map)[0];

        mask &= ~(1<<smp_processor_id());

        if (!mask)
                return 0;

        /* Can deadlock when called with interrupts disabled */
        WARN_ON(irqs_disabled());

        data.func = func;
        data.info = info;
        data.started = mask;
        data.wait = wait;
        if (wait)
                data.finished = mask;

        spin_lock(&call_lock);
        call_data = &data;
        wmb();
        /* Send a message to all other CPUs and wait for them to respond */
        send_CPI_allbutself(VIC_CALL_FUNCTION_CPI);

        /* Wait for response */
        while (data.started)
                barrier();

        if (wait)
                while (data.finished)
                        barrier();

        spin_unlock(&call_lock);

        return 0;
}
EXPORT_SYMBOL(smp_call_function);

/* Sorry about the name.  In an APIC based system, the APICs
 * themselves are programmed to send a timer interrupt.  This is used
 * by linux to reschedule the processor.  Voyager doesn't have this,
 * so we use the system clock to interrupt one processor, which in
 * turn, broadcasts a timer CPI to all the others --- we receive that
 * CPI here.  We don't use this actually for counting so losing
 * ticks doesn't matter 
 *
 * FIXME: For those CPU's which actually have a local APIC, we could
 * try to use it to trigger this interrupt instead of having to
 * broadcast the timer tick.  Unfortunately, all my pentium DYADs have
 * no local APIC, so I can't do this
 *
 * This function is currently a placeholder and is unused in the code */
fastcall void 
smp_apic_timer_interrupt(struct pt_regs *regs)
{
        wrapper_smp_local_timer_interrupt(regs);
}

/* All of the QUAD interrupt GATES */
fastcall void
smp_qic_timer_interrupt(struct pt_regs *regs)
{
        ack_QIC_CPI(QIC_TIMER_CPI);
        wrapper_smp_local_timer_interrupt(regs);
}

fastcall void
smp_qic_invalidate_interrupt(struct pt_regs *regs)
{
        ack_QIC_CPI(QIC_INVALIDATE_CPI);
        smp_invalidate_interrupt();
}

fastcall void
smp_qic_reschedule_interrupt(struct pt_regs *regs)
{
        ack_QIC_CPI(QIC_RESCHEDULE_CPI);
        smp_reschedule_interrupt();
}

fastcall void
smp_qic_enable_irq_interrupt(struct pt_regs *regs)
{
        ack_QIC_CPI(QIC_ENABLE_IRQ_CPI);
        smp_enable_irq_interrupt();
}

fastcall void
smp_qic_call_function_interrupt(struct pt_regs *regs)
{
        ack_QIC_CPI(QIC_CALL_FUNCTION_CPI);
        smp_call_function_interrupt();
}

fastcall void
smp_vic_cpi_interrupt(struct pt_regs *regs)
{
        __u8 cpu = smp_processor_id();

        if(is_cpu_quad())
                ack_QIC_CPI(VIC_CPI_LEVEL0);
        else
                ack_VIC_CPI(VIC_CPI_LEVEL0);

        if(test_and_clear_bit(VIC_TIMER_CPI, &vic_cpi_mailbox[cpu]))
                wrapper_smp_local_timer_interrupt(regs);
        if(test_and_clear_bit(VIC_INVALIDATE_CPI, &vic_cpi_mailbox[cpu]))
                smp_invalidate_interrupt();
        if(test_and_clear_bit(VIC_RESCHEDULE_CPI, &vic_cpi_mailbox[cpu]))
                smp_reschedule_interrupt();
        if(test_and_clear_bit(VIC_ENABLE_IRQ_CPI, &vic_cpi_mailbox[cpu]))
                smp_enable_irq_interrupt();
        if(test_and_clear_bit(VIC_CALL_FUNCTION_CPI, &vic_cpi_mailbox[cpu]))
                smp_call_function_interrupt();
}

static void
do_flush_tlb_all(void* info)
{
        unsigned long cpu = smp_processor_id();

        __flush_tlb_all();
        if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_LAZY)
                leave_mm(cpu);
}


/* flush the TLB of every active CPU in the system */
void
flush_tlb_all(void)
{
        on_each_cpu(do_flush_tlb_all, 0, 1, 1);
}

/* used to set up the trampoline for other CPUs when the memory manager
 * is sorted out */
void __init
smp_alloc_memory(void)
{
        trampoline_base = (__u32)alloc_bootmem_low_pages(PAGE_SIZE);
        if(__pa(trampoline_base) >= 0x93000)
                BUG();
}

/* send a reschedule CPI to one CPU by physical CPU number*/
void
smp_send_reschedule(int cpu)
{
        send_one_CPI(cpu, VIC_RESCHEDULE_CPI);
}


int
hard_smp_processor_id(void)
{
        __u8 i;
        __u8 cpumask = inb(VIC_PROC_WHO_AM_I);
        if((cpumask & QUAD_IDENTIFIER) == QUAD_IDENTIFIER)
                return cpumask & 0x1F;

        for(i = 0; i < 8; i++) {
                if(cpumask & (1<<i))
                        return i;
        }
        printk("** WARNING ** Illegal cpuid returned by VIC: %d", cpumask);
        return 0;
}

/* broadcast a halt to all other CPUs */
void
smp_send_stop(void)
{
        smp_call_function(smp_stop_cpu_function, NULL, 1, 1);
}

/* this function is triggered in time.c when a clock tick fires
 * we need to re-broadcast the tick to all CPUs */
void
smp_vic_timer_interrupt(struct pt_regs *regs)
{
        send_CPI_allbutself(VIC_TIMER_CPI);
        smp_local_timer_interrupt(regs);
}

/* local (per CPU) timer interrupt.  It does both profiling and
 * process statistics/rescheduling.
 *
 * We do profiling in every local tick, statistics/rescheduling
 * happen only every 'profiling multiplier' ticks. The default
 * multiplier is 1 and it can be changed by writing the new multiplier
 * value into /proc/profile.
 */
void
smp_local_timer_interrupt(struct pt_regs * regs)
{
        int cpu = smp_processor_id();
        long weight;

        profile_tick(CPU_PROFILING, regs);
        if (--per_cpu(prof_counter, cpu) <= 0) {
                /*
                 * The multiplier may have changed since the last time we got
                 * to this point as a result of the user writing to
                 * /proc/profile. In this case we need to adjust the APIC
                 * timer accordingly.
                 *
                 * Interrupts are already masked off at this point.
                 */
                per_cpu(prof_counter,cpu) = per_cpu(prof_multiplier, cpu);
                if (per_cpu(prof_counter, cpu) !=
                                        per_cpu(prof_old_multiplier, cpu)) {
                        /* FIXME: need to update the vic timer tick here */
                        per_cpu(prof_old_multiplier, cpu) =
                                                per_cpu(prof_counter, cpu);
                }

                update_process_times(user_mode_vm(regs));
        }

        if( ((1<<cpu) & voyager_extended_vic_processors) == 0)
                /* only extended VIC processors participate in
                 * interrupt distribution */
                return;

        /*
         * We take the 'long' return path, and there every subsystem
         * grabs the apropriate locks (kernel lock/ irq lock).
         *
         * we might want to decouple profiling from the 'long path',
         * and do the profiling totally in assembly.
         *
         * Currently this isn't too much of an issue (performance wise),
         * we can take more than 100K local irqs per second on a 100 MHz P5.
         */

        if((++vic_tick[cpu] & 0x7) != 0)
                return;
        /* get here every 16 ticks (about every 1/6 of a second) */

        /* Change our priority to give someone else a chance at getting
         * the IRQ. The algorithm goes like this:
         *
         * In the VIC, the dynamically routed interrupt is always
         * handled by the lowest priority eligible (i.e. receiving
         * interrupts) CPU.  If >1 eligible CPUs are equal lowest, the
         * lowest processor number gets it.
         *
         * The priority of a CPU is controlled by a special per-CPU
         * VIC priority register which is 3 bits wide 0 being lowest
         * and 7 highest priority..
         *
         * Therefore we subtract the average number of interrupts from
         * the number we've fielded.  If this number is negative, we
         * lower the activity count and if it is positive, we raise
         * it.
         *
         * I'm afraid this still leads to odd looking interrupt counts:
         * the totals are all roughly equal, but the individual ones
         * look rather skewed.
         *
         * FIXME: This algorithm is total crap when mixed with SMP
         * affinity code since we now try to even up the interrupt
         * counts when an affinity binding is keeping them on a
         * particular CPU*/
        weight = (vic_intr_count[cpu]*voyager_extended_cpus
                  - vic_intr_total) >> 4;
        weight += 4;
        if(weight > 7)
                weight = 7;
        if(weight < 0)
                weight = 0;
        
        outb((__u8)weight, VIC_PRIORITY_REGISTER);

#ifdef VOYAGER_DEBUG
        if((vic_tick[cpu] & 0xFFF) == 0) {
                /* print this message roughly every 25 secs */
                printk("VOYAGER SMP: vic_tick[%d] = %lu, weight = %ld\n",
                       cpu, vic_tick[cpu], weight);
        }
#endif
}

/* setup the profiling timer */
int 
setup_profiling_timer(unsigned int multiplier)
{
        int i;

        if ( (!multiplier))
                return -EINVAL;

        /* 
         * Set the new multiplier for each CPU. CPUs don't start using the
         * new values until the next timer interrupt in which they do process
         * accounting.
         */
        for (i = 0; i < NR_CPUS; ++i)
                per_cpu(prof_multiplier, i) = multiplier;

        return 0;
}


/*  The CPIs are handled in the per cpu 8259s, so they must be
 *  enabled to be received: FIX: enabling the CPIs in the early
 *  boot sequence interferes with bug checking; enable them later
 *  on in smp_init */
#define VIC_SET_GATE(cpi, vector) \
        set_intr_gate((cpi) + VIC_DEFAULT_CPI_BASE, (vector))
#define QIC_SET_GATE(cpi, vector) \
        set_intr_gate((cpi) + QIC_DEFAULT_CPI_BASE, (vector))

void __init
smp_intr_init(void)
{
        int i;

        /* initialize the per cpu irq mask to all disabled */
        for(i = 0; i < NR_CPUS; i++)
                vic_irq_mask[i] = 0xFFFF;

        VIC_SET_GATE(VIC_CPI_LEVEL0, vic_cpi_interrupt);

        VIC_SET_GATE(VIC_SYS_INT, vic_sys_interrupt);
        VIC_SET_GATE(VIC_CMN_INT, vic_cmn_interrupt);

        QIC_SET_GATE(QIC_TIMER_CPI, qic_timer_interrupt);
        QIC_SET_GATE(QIC_INVALIDATE_CPI, qic_invalidate_interrupt);
        QIC_SET_GATE(QIC_RESCHEDULE_CPI, qic_reschedule_interrupt);
        QIC_SET_GATE(QIC_ENABLE_IRQ_CPI, qic_enable_irq_interrupt);
        QIC_SET_GATE(QIC_CALL_FUNCTION_CPI, qic_call_function_interrupt);
        

        /* now put the VIC descriptor into the first 48 IRQs 
         *
         * This is for later: first 16 correspond to PC IRQs; next 16
         * are Primary MC IRQs and final 16 are Secondary MC IRQs */
        for(i = 0; i < 48; i++)
                irq_desc[i].handler = &vic_irq_type;
}

/* send a CPI at level cpi to a set of cpus in cpuset (set 1 bit per
 * processor to receive CPI */
static void
send_CPI(__u32 cpuset, __u8 cpi)
{
        int cpu;
        __u32 quad_cpuset = (cpuset & voyager_quad_processors);

        if(cpi < VIC_START_FAKE_CPI) {
                /* fake CPI are only used for booting, so send to the 
                 * extended quads as well---Quads must be VIC booted */
                outb((__u8)(cpuset), VIC_CPI_Registers[cpi]);
                return;
        }
        if(quad_cpuset)
                send_QIC_CPI(quad_cpuset, cpi);
        cpuset &= ~quad_cpuset;
        cpuset &= 0xff;         /* only first 8 CPUs vaild for VIC CPI */
        if(cpuset == 0)
                return;
        for_each_online_cpu(cpu) {
                if(cpuset & (1<<cpu))
                        set_bit(cpi, &vic_cpi_mailbox[cpu]);
        }
        if(cpuset)
                outb((__u8)cpuset, VIC_CPI_Registers[VIC_CPI_LEVEL0]);
}

/* Acknowledge receipt of CPI in the QIC, clear in QIC hardware and
 * set the cache line to shared by reading it.
 *
 * DON'T make this inline otherwise the cache line read will be
 * optimised away
 * */
static int
ack_QIC_CPI(__u8 cpi) {
        __u8 cpu = hard_smp_processor_id();

        cpi &= 7;

        outb(1<<cpi, QIC_INTERRUPT_CLEAR1);
        return voyager_quad_cpi_addr[cpu]->qic_cpi[cpi].cpi;
}

static void
ack_special_QIC_CPI(__u8 cpi)
{
        switch(cpi) {
        case VIC_CMN_INT:
                outb(QIC_CMN_INT, QIC_INTERRUPT_CLEAR0);
                break;
        case VIC_SYS_INT:
                outb(QIC_SYS_INT, QIC_INTERRUPT_CLEAR0);
                break;
        }
        /* also clear at the VIC, just in case (nop for non-extended proc) */
        ack_VIC_CPI(cpi);
}

/* Acknowledge receipt of CPI in the VIC (essentially an EOI) */
static void
ack_VIC_CPI(__u8 cpi)
{
#ifdef VOYAGER_DEBUG
        unsigned long flags;
        __u16 isr;
        __u8 cpu = smp_processor_id();

        local_irq_save(flags);
        isr = vic_read_isr();
        if((isr & (1<<(cpi &7))) == 0) {
                printk("VOYAGER SMP: CPU%d lost CPI%d\n", cpu, cpi);
        }
#endif
        /* send specific EOI; the two system interrupts have
         * bit 4 set for a separate vector but behave as the
         * corresponding 3 bit intr */
        outb_p(0x60|(cpi & 7),0x20);

#ifdef VOYAGER_DEBUG
        if((vic_read_isr() & (1<<(cpi &7))) != 0) {
                printk("VOYAGER SMP: CPU%d still asserting CPI%d\n", cpu, cpi);
        }
        local_irq_restore(flags);
#endif
}

/* cribbed with thanks from irq.c */
#define __byte(x,y)     (((unsigned char *)&(y))[x])
#define cached_21(cpu)  (__byte(0,vic_irq_mask[cpu]))
#define cached_A1(cpu)  (__byte(1,vic_irq_mask[cpu]))

static unsigned int
startup_vic_irq(unsigned int irq)
{
        enable_vic_irq(irq);

        return 0;
}

/* The enable and disable routines.  This is where we run into
 * conflicting architectural philosophy.  Fundamentally, the voyager
 * architecture does not expect to have to disable interrupts globally
 * (the IRQ controllers belong to each CPU).  The processor masquerade
 * which is used to start the system shouldn't be used in a running OS
 * since it will cause great confusion if two separate CPUs drive to
 * the same IRQ controller (I know, I've tried it).
 *
 * The solution is a variant on the NCR lazy SPL design:
 *
 * 1) To disable an interrupt, do nothing (other than set the
 *    IRQ_DISABLED flag).  This dares the interrupt actually to arrive.
 *
 * 2) If the interrupt dares to come in, raise the local mask against
 *    it (this will result in all the CPU masks being raised
 *    eventually).
 *
 * 3) To enable the interrupt, lower the mask on the local CPU and
 *    broadcast an Interrupt enable CPI which causes all other CPUs to
 *    adjust their masks accordingly.  */

static void
enable_vic_irq(unsigned int irq)
{
        /* linux doesn't to processor-irq affinity, so enable on
         * all CPUs we know about */
        int cpu = smp_processor_id(), real_cpu;
        __u16 mask = (1<<irq);
        __u32 processorList = 0;
        unsigned long flags;

        VDEBUG(("VOYAGER: enable_vic_irq(%d) CPU%d affinity 0x%lx\n",
                irq, cpu, cpu_irq_affinity[cpu]));
        spin_lock_irqsave(&vic_irq_lock, flags);
        for_each_online_cpu(real_cpu) {
                if(!(voyager_extended_vic_processors & (1<<real_cpu)))
                        continue;
                if(!(cpu_irq_affinity[real_cpu] & mask)) {
                        /* irq has no affinity for this CPU, ignore */
                        continue;
                }
                if(real_cpu == cpu) {
                        enable_local_vic_irq(irq);
                }
                else if(vic_irq_mask[real_cpu] & mask) {
                        vic_irq_enable_mask[real_cpu] |= mask;
                        processorList |= (1<<real_cpu);
                }
        }
        spin_unlock_irqrestore(&vic_irq_lock, flags);
        if(processorList)
                send_CPI(processorList, VIC_ENABLE_IRQ_CPI);
}

static void
disable_vic_irq(unsigned int irq)
{
        /* lazy disable, do nothing */
}

static void
enable_local_vic_irq(unsigned int irq)
{
        __u8 cpu = smp_processor_id();
        __u16 mask = ~(1 << irq);
        __u16 old_mask = vic_irq_mask[cpu];

        vic_irq_mask[cpu] &= mask;
        if(vic_irq_mask[cpu] == old_mask)
                return;

        VDEBUG(("VOYAGER DEBUG: Enabling irq %d in hardware on CPU %d\n",
                irq, cpu));

        if (irq & 8) {
                outb_p(cached_A1(cpu),0xA1);
                (void)inb_p(0xA1);
        }
        else {
                outb_p(cached_21(cpu),0x21);
                (void)inb_p(0x21);
        }
}

static void
disable_local_vic_irq(unsigned int irq)
{
        __u8 cpu = smp_processor_id();
        __u16 mask = (1 << irq);
        __u16 old_mask = vic_irq_mask[cpu];

        if(irq == 7)
                return;

        vic_irq_mask[cpu] |= mask;
        if(old_mask == vic_irq_mask[cpu])
                return;

        VDEBUG(("VOYAGER DEBUG: Disabling irq %d in hardware on CPU %d\n",
                irq, cpu));

        if (irq & 8) {
                outb_p(cached_A1(cpu),0xA1);
                (void)inb_p(0xA1);
        }
        else {
                outb_p(cached_21(cpu),0x21);
                (void)inb_p(0x21);
        }
}

/* The VIC is level triggered, so the ack can only be issued after the
 * interrupt completes.  However, we do Voyager lazy interrupt
 * handling here: It is an extremely expensive operation to mask an
 * interrupt in the vic, so we merely set a flag (IRQ_DISABLED).  If
 * this interrupt actually comes in, then we mask and ack here to push
 * the interrupt off to another CPU */
static void
before_handle_vic_irq(unsigned int irq)
{
        irq_desc_t *desc = irq_desc + irq;
        __u8 cpu = smp_processor_id();

        _raw_spin_lock(&vic_irq_lock);
        vic_intr_total++;
        vic_intr_count[cpu]++;

        if(!(cpu_irq_affinity[cpu] & (1<<irq))) {
                /* The irq is not in our affinity mask, push it off
                 * onto another CPU */
                VDEBUG(("VOYAGER DEBUG: affinity triggered disable of irq %d on cpu %d\n",
                        irq, cpu));
                disable_local_vic_irq(irq);
                /* set IRQ_INPROGRESS to prevent the handler in irq.c from
                 * actually calling the interrupt routine */
                desc->status |= IRQ_REPLAY | IRQ_INPROGRESS;
        } else if(desc->status & IRQ_DISABLED) {
                /* Damn, the interrupt actually arrived, do the lazy
                 * disable thing. The interrupt routine in irq.c will
                 * not handle a IRQ_DISABLED interrupt, so nothing more
                 * need be done here */
                VDEBUG(("VOYAGER DEBUG: lazy disable of irq %d on CPU %d\n",
                        irq, cpu));
                disable_local_vic_irq(irq);
                desc->status |= IRQ_REPLAY;
        } else {
                desc->status &= ~IRQ_REPLAY;
        }

        _raw_spin_unlock(&vic_irq_lock);
}

/* Finish the VIC interrupt: basically mask */
static void
after_handle_vic_irq(unsigned int irq)
{
        irq_desc_t *desc = irq_desc + irq;

        _raw_spin_lock(&vic_irq_lock);
        {
                unsigned int status = desc->status & ~IRQ_INPROGRESS;
#ifdef VOYAGER_DEBUG
                __u16 isr;
#endif

                desc->status = status;
                if ((status & IRQ_DISABLED))
                        disable_local_vic_irq(irq);
#ifdef VOYAGER_DEBUG
                /* DEBUG: before we ack, check what's in progress */
                isr = vic_read_isr();
                if((isr & (1<<irq) && !(status & IRQ_REPLAY)) == 0) {
                        int i;
                        __u8 cpu = smp_processor_id();
                        __u8 real_cpu;
                        int mask; /* Um... initialize me??? --RR */

                        printk("VOYAGER SMP: CPU%d lost interrupt %d\n",
                               cpu, irq);
                        for_each_cpu(real_cpu, mask) {

                                outb(VIC_CPU_MASQUERADE_ENABLE | real_cpu,
                                     VIC_PROCESSOR_ID);
                                isr = vic_read_isr();
                                if(isr & (1<<irq)) {
                                        printk("VOYAGER SMP: CPU%d ack irq %d\n",
                                               real_cpu, irq);
                                        ack_vic_irq(irq);
                                }
                                outb(cpu, VIC_PROCESSOR_ID);
                        }
                }
#endif /* VOYAGER_DEBUG */
                /* as soon as we ack, the interrupt is eligible for
                 * receipt by another CPU so everything must be in
                 * order here  */
                ack_vic_irq(irq);
                if(status & IRQ_REPLAY) {
                        /* replay is set if we disable the interrupt
                         * in the before_handle_vic_irq() routine, so
                         * clear the in progress bit here to allow the
                         * next CPU to handle this correctly */
                        desc->status &= ~(IRQ_REPLAY | IRQ_INPROGRESS);
                }
#ifdef VOYAGER_DEBUG
                isr = vic_read_isr();
                if((isr & (1<<irq)) != 0)
                        printk("VOYAGER SMP: after_handle_vic_irq() after ack irq=%d, isr=0x%x\n",
                               irq, isr);
#endif /* VOYAGER_DEBUG */
        }
        _raw_spin_unlock(&vic_irq_lock);

        /* All code after this point is out of the main path - the IRQ
         * may be intercepted by another CPU if reasserted */
}


/* Linux processor - interrupt affinity manipulations.
 *
 * For each processor, we maintain a 32 bit irq affinity mask.
 * Initially it is set to all 1's so every processor accepts every
 * interrupt.  In this call, we change the processor's affinity mask:
 *
 * Change from enable to disable:
 *
 * If the interrupt ever comes in to the processor, we will disable it
 * and ack it to push it off to another CPU, so just accept the mask here.
 *
 * Change from disable to enable:
 *
 * change the mask and then do an interrupt enable CPI to re-enable on
 * the selected processors */

void
set_vic_irq_affinity(unsigned int irq, cpumask_t mask)
{
        /* Only extended processors handle interrupts */
        unsigned long real_mask;
        unsigned long irq_mask = 1 << irq;
        int cpu;

        real_mask = cpus_addr(mask)[0] & voyager_extended_vic_processors;
        
        if(cpus_addr(mask)[0] == 0)
                /* can't have no cpu's to accept the interrupt -- extremely
                 * bad things will happen */
                return;

        if(irq == 0)
                /* can't change the affinity of the timer IRQ.  This
                 * is due to the constraint in the voyager
                 * architecture that the CPI also comes in on and IRQ
                 * line and we have chosen IRQ0 for this.  If you
                 * raise the mask on this interrupt, the processor
                 * will no-longer be able to accept VIC CPIs */
                return;

        if(irq >= 32) 
                /* You can only have 32 interrupts in a voyager system
                 * (and 32 only if you have a secondary microchannel
                 * bus) */
                return;

        for_each_online_cpu(cpu) {
                unsigned long cpu_mask = 1 << cpu;
                
                if(cpu_mask & real_mask) {
                        /* enable the interrupt for this cpu */
                        cpu_irq_affinity[cpu] |= irq_mask;
                } else {
                        /* disable the interrupt for this cpu */
                        cpu_irq_affinity[cpu] &= ~irq_mask;
                }
        }
        /* this is magic, we now have the correct affinity maps, so
         * enable the interrupt.  This will send an enable CPI to
         * those cpu's who need to enable it in their local masks,
         * causing them to correct for the new affinity . If the
         * interrupt is currently globally disabled, it will simply be
         * disabled again as it comes in (voyager lazy disable).  If
         * the affinity map is tightened to disable the interrupt on a
         * cpu, it will be pushed off when it comes in */
        enable_vic_irq(irq);
}

static void
ack_vic_irq(unsigned int irq)
{
        if (irq & 8) {
                outb(0x62,0x20);        /* Specific EOI to cascade */
                outb(0x60|(irq & 7),0xA0);
        } else {
                outb(0x60 | (irq & 7),0x20);
        }
}

/* enable the CPIs.  In the VIC, the CPIs are delivered by the 8259
 * but are not vectored by it.  This means that the 8259 mask must be
 * lowered to receive them */
static __init void
vic_enable_cpi(void)
{
        __u8 cpu = smp_processor_id();
        
        /* just take a copy of the current mask (nop for boot cpu) */
        vic_irq_mask[cpu] = vic_irq_mask[boot_cpu_id];

        enable_local_vic_irq(VIC_CPI_LEVEL0);
        enable_local_vic_irq(VIC_CPI_LEVEL1);
        /* for sys int and cmn int */
        enable_local_vic_irq(7);

        if(is_cpu_quad()) {
                outb(QIC_DEFAULT_MASK0, QIC_MASK_REGISTER0);
                outb(QIC_CPI_ENABLE, QIC_MASK_REGISTER1);
                VDEBUG(("VOYAGER SMP: QIC ENABLE CPI: CPU%d: MASK 0x%x\n",
                        cpu, QIC_CPI_ENABLE));
        }

        VDEBUG(("VOYAGER SMP: ENABLE CPI: CPU%d: MASK 0x%x\n",
                cpu, vic_irq_mask[cpu]));
}

void
voyager_smp_dump()
{
        int old_cpu = smp_processor_id(), cpu;

        /* dump the interrupt masks of each processor */
        for_each_online_cpu(cpu) {
                __u16 imr, isr, irr;
                unsigned long flags;

                local_irq_save(flags);
                outb(VIC_CPU_MASQUERADE_ENABLE | cpu, VIC_PROCESSOR_ID);
                imr = (inb(0xa1) << 8) | inb(0x21);
                outb(0x0a, 0xa0);
                irr = inb(0xa0) << 8;
                outb(0x0a, 0x20);
                irr |= inb(0x20);
                outb(0x0b, 0xa0);
                isr = inb(0xa0) << 8;
                outb(0x0b, 0x20);
                isr |= inb(0x20);
                outb(old_cpu, VIC_PROCESSOR_ID);
                local_irq_restore(flags);
                printk("\tCPU%d: mask=0x%x, IMR=0x%x, IRR=0x%x, ISR=0x%x\n",
                       cpu, vic_irq_mask[cpu], imr, irr, isr);
#if 0
                /* These lines are put in to try to unstick an un ack'd irq */
                if(isr != 0) {
                        int irq;
                        for(irq=0; irq<16; irq++) {
                                if(isr & (1<<irq)) {
                                        printk("\tCPU%d: ack irq %d\n",
                                               cpu, irq);
                                        local_irq_save(flags);
                                        outb(VIC_CPU_MASQUERADE_ENABLE | cpu,
                                             VIC_PROCESSOR_ID);
                                        ack_vic_irq(irq);
                                        outb(old_cpu, VIC_PROCESSOR_ID);
                                        local_irq_restore(flags);
                                }
                        }
                }
#endif
        }
}

void
smp_voyager_power_off(void *dummy)
{
        if(smp_processor_id() == boot_cpu_id) 
                voyager_power_off();
        else
                smp_stop_cpu_function(NULL);
}

void __init
smp_prepare_cpus(unsigned int max_cpus)
{
        /* FIXME: ignore max_cpus for now */
        smp_boot_cpus();
}

void __devinit smp_prepare_boot_cpu(void)
{
        cpu_set(smp_processor_id(), cpu_online_map);
        cpu_set(smp_processor_id(), cpu_callout_map);
        cpu_set(smp_processor_id(), cpu_possible_map);
}

int __devinit
__cpu_up(unsigned int cpu)
{
        /* This only works at boot for x86.  See "rewrite" above. */
        if (cpu_isset(cpu, smp_commenced_mask))
                return -ENOSYS;

        /* In case one didn't come up */
        if (!cpu_isset(cpu, cpu_callin_map))
                return -EIO;
        /* Unleash the CPU! */
        cpu_set(cpu, smp_commenced_mask);
        while (!cpu_isset(cpu, cpu_online_map))
                mb();
        return 0;
}

void __init 
smp_cpus_done(unsigned int max_cpus)
{
        zap_low_mappings();
}