/*
 *  linux/arch/arm/kernel/process.c
 *
 *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
 *  Origional Copyright (C) 1995  Linus Torvalds
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <stdarg.h>

#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <linux/init.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/leds.h>
#include <asm/uaccess.h>

/*
 * Values for cpu_do_idle()
 */
#define IDLE_WAIT_SLOW  0
#define IDLE_WAIT_FAST  1
#define IDLE_CLOCK_SLOW 2
#define IDLE_CLOCK_FAST 3

extern const char *processor_modes[];
extern void setup_mm_for_reboot(char mode);

static volatile int hlt_counter;

#include <asm/arch/system.h>

void disable_hlt(void)
{
        hlt_counter++;
}

void enable_hlt(void)
{
        hlt_counter--;
}

static int __init nohlt_setup(char *__unused)
{
        hlt_counter = 1;
        return 1;
}

static int __init hlt_setup(char *__unused)
{
        hlt_counter = 0;
        return 1;
}

__setup("nohlt", nohlt_setup);
__setup("hlt", hlt_setup);

/*
 * The following aren't currently used.
 */
void (*pm_idle)(void);
void (*pm_power_off)(void);

/*
 * The idle thread.  We try to conserve power, while trying to keep
 * overall latency low.  The architecture specific idle is passed
 * a value to indicate the level of "idleness" of the system.
 */
void cpu_idle(void)
{
        /* endless idle loop with no priority at all */
        init_idle();
        current->nice = 20;
        current->counter = -100;

        while (1) {
                void (*idle)(void) = pm_idle;
                if (!idle)
                        idle = arch_idle;
                leds_event(led_idle_start);
                while (!current->need_resched)
                        idle();
                leds_event(led_idle_end);
                schedule();
#ifndef CONFIG_NO_PGT_CACHE
                check_pgt_cache();
#endif
        }
}

static char reboot_mode = 'h';

int __init reboot_setup(char *str)
{
        reboot_mode = str[0];
        return 1;
}

__setup("reboot=", reboot_setup);

void machine_halt(void)
{
        leds_event(led_halted);
}

void machine_power_off(void)
{
        leds_event(led_halted);
        if (pm_power_off)
                pm_power_off();
}

void machine_restart(char * __unused)
{
        /*
         * Clean and disable cache, and turn off interrupts
         */
        cpu_proc_fin();

        /*
         * Tell the mm system that we are going to reboot -
         * we may need it to insert some 1:1 mappings so that
         * soft boot works.
         */
        setup_mm_for_reboot(reboot_mode);

        /*
         * Now call the architecture specific reboot code.
         */
        arch_reset(reboot_mode);

        /*
         * Whoops - the architecture was unable to reboot.
         * Tell the user!
         */
        mdelay(1000);
        printk("Reboot failed -- System halted\n");
        while (1);
}

void show_regs(struct pt_regs * regs)
{
        unsigned long flags;

        flags = condition_codes(regs);

        printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
               "sp : %08lx  ip : %08lx  fp : %08lx\n",
                instruction_pointer(regs),
                regs->ARM_lr, print_tainted(), regs->ARM_sp,
                regs->ARM_ip, regs->ARM_fp);
        printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
                regs->ARM_r10, regs->ARM_r9,
                regs->ARM_r8);
        printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
                regs->ARM_r7, regs->ARM_r6,
                regs->ARM_r5, regs->ARM_r4);
        printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
                regs->ARM_r3, regs->ARM_r2,
                regs->ARM_r1, regs->ARM_r0);
        printk("Flags: %c%c%c%c",
                flags & CC_N_BIT ? 'N' : 'n',
                flags & CC_Z_BIT ? 'Z' : 'z',
                flags & CC_C_BIT ? 'C' : 'c',
                flags & CC_V_BIT ? 'V' : 'v');
        printk("  IRQs %s  FIQs %s  Mode %s%s  Segment %s\n",
                interrupts_enabled(regs) ? "on" : "off",
                fast_interrupts_enabled(regs) ? "on" : "off",
                processor_modes[processor_mode(regs)],
                thumb_mode(regs) ? " (T)" : "",
                get_fs() == get_ds() ? "kernel" : "user");
#if defined(CONFIG_CPU_32)
        {
                int ctrl, transbase, dac;
                  __asm__ (
                "       mrc p15, 0, %0, c1, c0\n"
                "       mrc p15, 0, %1, c2, c0\n"
                "       mrc p15, 0, %2, c3, c0\n"
                : "=r" (ctrl), "=r" (transbase), "=r" (dac));
                printk("Control: %04X  Table: %08X  DAC: %08X\n",
                        ctrl, transbase, dac);
        }
#endif
}

void show_fpregs(struct user_fp *regs)
{
        int i;

        for (i = 0; i < 8; i++) {
                unsigned long *p;
                char type;

                p = (unsigned long *)(regs->fpregs + i);

                switch (regs->ftype[i]) {
                        case 1: type = 'f'; break;
                        case 2: type = 'd'; break;
                        case 3: type = 'e'; break;
                        default: type = '?'; break;
                }
                if (regs->init_flag)
                        type = '?';

                printk("  f%d(%c): %08lx %08lx %08lx%c",
                        i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
        }
                        

        printk("FPSR: %08lx FPCR: %08lx\n",
                (unsigned long)regs->fpsr,
                (unsigned long)regs->fpcr);
}

/*
 * Task structure and kernel stack allocation.
 */
static struct task_struct *task_struct_head;
static unsigned int nr_task_struct;

#ifdef CONFIG_CPU_32
#define EXTRA_TASK_STRUCT       4
#else
#define EXTRA_TASK_STRUCT       0
#endif

struct task_struct *alloc_task_struct(void)
{
        struct task_struct *tsk;

        if (EXTRA_TASK_STRUCT)
                tsk = task_struct_head;
        else
                tsk = NULL;

        if (tsk) {
                task_struct_head = tsk->next_task;
                nr_task_struct -= 1;
        } else
                tsk = ll_alloc_task_struct();

#ifdef CONFIG_SYSRQ
        /*
         * The stack must be cleared if you want SYSRQ-T to
         * give sensible stack usage information
         */
        if (tsk) {
                char *p = (char *)tsk;
                memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
        }
#endif
        return tsk;
}

void __free_task_struct(struct task_struct *p)
{
        if (EXTRA_TASK_STRUCT && nr_task_struct < EXTRA_TASK_STRUCT) {
                p->next_task = task_struct_head;
                task_struct_head = p;
                nr_task_struct += 1;
        } else
                ll_free_task_struct(p);
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
}

void flush_thread(void)
{
        memset(&current->thread.debug, 0, sizeof(struct debug_info));
        memset(&current->thread.fpstate, 0, sizeof(union fp_state));
        current->used_math = 0;
        current->flags &= ~PF_USEDFPU;
}

void release_thread(struct task_struct *dead_task)
{
}

asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");

int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
        unsigned long unused,
        struct task_struct * p, struct pt_regs * regs)
{
        struct pt_regs * childregs;
        struct context_save_struct * save;

        atomic_set(&p->thread.refcount, 1);

        childregs = ((struct pt_regs *)((unsigned long)p + 8192)) - 1;
        *childregs = *regs;
        childregs->ARM_r0 = 0;
        childregs->ARM_sp = esp;

        save = ((struct context_save_struct *)(childregs)) - 1;
        *save = INIT_CSS;
        save->pc |= (unsigned long)ret_from_fork;

        p->thread.save = save;

        return 0;
}

/*
 * fill in the fpe structure for a core dump...
 */
int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
{
        if (current->used_math)
                memcpy(fp, &current->thread.fpstate.soft, sizeof (*fp));

        return current->used_math;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{
        struct task_struct *tsk = current;

        dump->magic = CMAGIC;
        dump->start_code = tsk->mm->start_code;
        dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);

        dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
        dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
        dump->u_ssize = 0;

        dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
        dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
        dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn;
        dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
        dump->u_debugreg[4] = tsk->thread.debug.nsaved;

        if (dump->start_stack < 0x04000000)
                dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;

        dump->regs = *regs;
        dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
}

/*
 * This is the mechanism for creating a new kernel thread.
 *
 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 * who haven't done an "execve()") should use this: it will work within
 * a system call from a "real" process, but the process memory space will
 * not be free'd until both the parent and the child have exited.
 */
pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
        pid_t __ret;

        __asm__ __volatile__(
        "orr    r0, %1, %2      @ kernel_thread sys_clone
        mov     r1, #0
        "__syscall(clone)"
        movs    %0, r0          @ if we are the child
        bne     1f
        mov     fp, #0          @ ensure that fp is zero
        mov     r0, %4
        mov     lr, pc
        mov     pc, %3
        b       sys_exit
1:      "
        : "=r" (__ret)
        : "Ir" (flags), "I" (CLONE_VM), "r" (fn), "r" (arg)
        : "r0", "r1", "lr");
        return __ret;
}

/*
 * These bracket the sleeping functions..
 */
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
#define first_sched     ((unsigned long) scheduling_functions_start_here)
#define last_sched      ((unsigned long) scheduling_functions_end_here)

unsigned long get_wchan(struct task_struct *p)
{
        unsigned long fp, lr;
        unsigned long stack_page;
        int count = 0;
        if (!p || p == current || p->state == TASK_RUNNING)
                return 0;

        stack_page = 4096 + (unsigned long)p;
        fp = get_css_fp(&p->thread);
        do {
                if (fp < stack_page || fp > 4092+stack_page)
                        return 0;
                lr = pc_pointer (((unsigned long *)fp)[-1]);
                if (lr < first_sched || lr > last_sched)
                        return lr;
                fp = *(unsigned long *) (fp - 12);
        } while (count ++ < 16);
        return 0;
}