/* sun4m_smp.c: Sparc SUN4M SMP support.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 */

#include <asm/head.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/profile.h>
#include <linux/delay.h>
#include <linux/cpu.h>

#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/irq_regs.h>

#include <asm/ptrace.h>
#include <asm/atomic.h>

#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/oplib.h>
#include <asm/cpudata.h>

#include "irq.h"

#define IRQ_CROSS_CALL          15

extern ctxd_t *srmmu_ctx_table_phys;

extern volatile unsigned long cpu_callin_map[NR_CPUS];
extern unsigned char boot_cpu_id;

extern cpumask_t smp_commenced_mask;

extern int __smp4m_processor_id(void);

/*#define SMP_DEBUG*/

#ifdef SMP_DEBUG
#define SMP_PRINTK(x)   printk x
#else
#define SMP_PRINTK(x)
#endif

static inline unsigned long
swap_ulong(volatile unsigned long *ptr, unsigned long val)
{
        __asm__ __volatile__("swap [%1], %0\n\t" :
                             "=&r" (val), "=&r" (ptr) :
                             "0" (val), "1" (ptr));
        return val;
}

static void smp_setup_percpu_timer(void);
extern void cpu_probe(void);

void __cpuinit smp4m_callin(void)
{
        int cpuid = hard_smp_processor_id();

        local_flush_cache_all();
        local_flush_tlb_all();

        notify_cpu_starting(cpuid);

        /* Get our local ticker going. */
        smp_setup_percpu_timer();

        calibrate_delay();
        smp_store_cpu_info(cpuid);

        local_flush_cache_all();
        local_flush_tlb_all();

        /*
         * Unblock the master CPU _only_ when the scheduler state
         * of all secondary CPUs will be up-to-date, so after
         * the SMP initialization the master will be just allowed
         * to call the scheduler code.
         */
        /* Allow master to continue. */
        swap_ulong(&cpu_callin_map[cpuid], 1);

        /* XXX: What's up with all the flushes? */
        local_flush_cache_all();
        local_flush_tlb_all();
        
        cpu_probe();

        /* Fix idle thread fields. */
        __asm__ __volatile__("ld [%0], %%g6\n\t"
                             : : "r" (&current_set[cpuid])
                             : "memory" /* paranoid */);

        /* Attach to the address space of init_task. */
        atomic_inc(&init_mm.mm_count);
        current->active_mm = &init_mm;

        while (!cpu_isset(cpuid, smp_commenced_mask))
                mb();

        local_irq_enable();

        set_cpu_online(cpuid, true);
}

/*
 *      Cycle through the processors asking the PROM to start each one.
 */
 
extern struct linux_prom_registers smp_penguin_ctable;

void __init smp4m_boot_cpus(void)
{
        smp_setup_percpu_timer();
        local_flush_cache_all();
}

int __cpuinit smp4m_boot_one_cpu(int i)
{
        extern unsigned long sun4m_cpu_startup;
        unsigned long *entry = &sun4m_cpu_startup;
        struct task_struct *p;
        int timeout;
        int cpu_node;

        cpu_find_by_mid(i, &cpu_node);

        /* Cook up an idler for this guy. */
        p = fork_idle(i);
        current_set[i] = task_thread_info(p);
        /* See trampoline.S for details... */
        entry += ((i-1) * 3);

        /*
         * Initialize the contexts table
         * Since the call to prom_startcpu() trashes the structure,
         * we need to re-initialize it for each cpu
         */
        smp_penguin_ctable.which_io = 0;
        smp_penguin_ctable.phys_addr = (unsigned int) srmmu_ctx_table_phys;
        smp_penguin_ctable.reg_size = 0;

        /* whirrr, whirrr, whirrrrrrrrr... */
        printk("Starting CPU %d at %p\n", i, entry);
        local_flush_cache_all();
        prom_startcpu(cpu_node,
                      &smp_penguin_ctable, 0, (char *)entry);

        /* wheee... it's going... */
        for(timeout = 0; timeout < 10000; timeout++) {
                if(cpu_callin_map[i])
                        break;
                udelay(200);
        }

        if (!(cpu_callin_map[i])) {
                printk("Processor %d is stuck.\n", i);
                return -ENODEV;
        }

        local_flush_cache_all();
        return 0;
}

void __init smp4m_smp_done(void)
{
        int i, first;
        int *prev;

        /* setup cpu list for irq rotation */
        first = 0;
        prev = &first;
        for_each_online_cpu(i) {
                *prev = i;
                prev = &cpu_data(i).next;
        }
        *prev = first;
        local_flush_cache_all();

        /* Ok, they are spinning and ready to go. */
}

/* At each hardware IRQ, we get this called to forward IRQ reception
 * to the next processor.  The caller must disable the IRQ level being
 * serviced globally so that there are no double interrupts received.
 *
 * XXX See sparc64 irq.c.
 */
void smp4m_irq_rotate(int cpu)
{
        int next = cpu_data(cpu).next;
        if (next != cpu)
                set_irq_udt(next);
}

static struct smp_funcall {
        smpfunc_t func;
        unsigned long arg1;
        unsigned long arg2;
        unsigned long arg3;
        unsigned long arg4;
        unsigned long arg5;
        unsigned long processors_in[SUN4M_NCPUS];  /* Set when ipi entered. */
        unsigned long processors_out[SUN4M_NCPUS]; /* Set when ipi exited. */
} ccall_info;

static DEFINE_SPINLOCK(cross_call_lock);

/* Cross calls must be serialized, at least currently. */
static void smp4m_cross_call(smpfunc_t func, cpumask_t mask, unsigned long arg1,
                             unsigned long arg2, unsigned long arg3,
                             unsigned long arg4)
{
                register int ncpus = SUN4M_NCPUS;
                unsigned long flags;

                spin_lock_irqsave(&cross_call_lock, flags);

                /* Init function glue. */
                ccall_info.func = func;
                ccall_info.arg1 = arg1;
                ccall_info.arg2 = arg2;
                ccall_info.arg3 = arg3;
                ccall_info.arg4 = arg4;
                ccall_info.arg5 = 0;

                /* Init receive/complete mapping, plus fire the IPI's off. */
                {
                        register int i;

                        cpu_clear(smp_processor_id(), mask);
                        cpus_and(mask, cpu_online_map, mask);
                        for(i = 0; i < ncpus; i++) {
                                if (cpu_isset(i, mask)) {
                                        ccall_info.processors_in[i] = 0;
                                        ccall_info.processors_out[i] = 0;
                                        set_cpu_int(i, IRQ_CROSS_CALL);
                                } else {
                                        ccall_info.processors_in[i] = 1;
                                        ccall_info.processors_out[i] = 1;
                                }
                        }
                }

                {
                        register int i;

                        i = 0;
                        do {
                                if (!cpu_isset(i, mask))
                                        continue;
                                while(!ccall_info.processors_in[i])
                                        barrier();
                        } while(++i < ncpus);

                        i = 0;
                        do {
                                if (!cpu_isset(i, mask))
                                        continue;
                                while(!ccall_info.processors_out[i])
                                        barrier();
                        } while(++i < ncpus);
                }

                spin_unlock_irqrestore(&cross_call_lock, flags);
}

/* Running cross calls. */
void smp4m_cross_call_irq(void)
{
        int i = smp_processor_id();

        ccall_info.processors_in[i] = 1;
        ccall_info.func(ccall_info.arg1, ccall_info.arg2, ccall_info.arg3,
                        ccall_info.arg4, ccall_info.arg5);
        ccall_info.processors_out[i] = 1;
}

extern void sun4m_clear_profile_irq(int cpu);

void smp4m_percpu_timer_interrupt(struct pt_regs *regs)
{
        struct pt_regs *old_regs;
        int cpu = smp_processor_id();

        old_regs = set_irq_regs(regs);

        sun4m_clear_profile_irq(cpu);

        profile_tick(CPU_PROFILING);

        if(!--prof_counter(cpu)) {
                int user = user_mode(regs);

                irq_enter();
                update_process_times(user);
                irq_exit();

                prof_counter(cpu) = prof_multiplier(cpu);
        }
        set_irq_regs(old_regs);
}

extern unsigned int lvl14_resolution;

static void __cpuinit smp_setup_percpu_timer(void)
{
        int cpu = smp_processor_id();

        prof_counter(cpu) = prof_multiplier(cpu) = 1;
        load_profile_irq(cpu, lvl14_resolution);

        if(cpu == boot_cpu_id)
                enable_pil_irq(14);
}

static void __init smp4m_blackbox_id(unsigned *addr)
{
        int rd = *addr & 0x3e000000;
        int rs1 = rd >> 11;
        
        addr[0] = 0x81580000 | rd;              /* rd %tbr, reg */
        addr[1] = 0x8130200c | rd | rs1;        /* srl reg, 0xc, reg */
        addr[2] = 0x80082003 | rd | rs1;        /* and reg, 3, reg */
}

static void __init smp4m_blackbox_current(unsigned *addr)
{
        int rd = *addr & 0x3e000000;
        int rs1 = rd >> 11;
        
        addr[0] = 0x81580000 | rd;              /* rd %tbr, reg */
        addr[2] = 0x8130200a | rd | rs1;        /* srl reg, 0xa, reg */
        addr[4] = 0x8008200c | rd | rs1;        /* and reg, 0xc, reg */
}

void __init sun4m_init_smp(void)
{
        BTFIXUPSET_BLACKBOX(hard_smp_processor_id, smp4m_blackbox_id);
        BTFIXUPSET_BLACKBOX(load_current, smp4m_blackbox_current);
        BTFIXUPSET_CALL(smp_cross_call, smp4m_cross_call, BTFIXUPCALL_NORM);
        BTFIXUPSET_CALL(__hard_smp_processor_id, __smp4m_processor_id, BTFIXUPCALL_NORM);
}