Archipelago » qemu

/*

 * QEMU generic PowerPC hardware System Emulator

 *

 * Copyright (c) 2003-2007 Jocelyn Mayer

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "hw.h"

#include "ppc.h"

#include "qemu-timer.h"

#include "sysemu.h"

#include "nvram.h"

//#define PPC_DEBUG_IRQ

//#define PPC_DEBUG_TB

extern FILE *logfile;

extern int loglevel;

static void cpu_ppc_tb_stop (CPUState *env);

static void cpu_ppc_tb_start (CPUState *env);

static void ppc_set_irq (CPUState *env, int n_IRQ, int level)

{

    if (level) {

        env->pending_interrupts |= 1 << n_IRQ;

        cpu_interrupt(env, CPU_INTERRUPT_HARD);

    } else {

        env->pending_interrupts &= ~(1 << n_IRQ);

        if (env->pending_interrupts == 0)

            cpu_reset_interrupt(env, CPU_INTERRUPT_HARD);

    }

#if defined(PPC_DEBUG_IRQ)

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "%s: %p n_IRQ %d level %d => pending %08" PRIx32

                "req %08x\n", __func__, env, n_IRQ, level,

                env->pending_interrupts, env->interrupt_request);

    }

#endif

}

/* PowerPC 6xx / 7xx internal IRQ controller */

static void ppc6xx_set_irq (void *opaque, int pin, int level)

{

    CPUState *env = opaque;

    int cur_level;

#if defined(PPC_DEBUG_IRQ)

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "%s: env %p pin %d level %d\n", __func__,

                env, pin, level);

    }

#endif

    cur_level = (env->irq_input_state >> pin) & 1;

    /* Don't generate spurious events */

    if ((cur_level == 1 && level == 0) || (cur_level == 0 && level != 0)) {

        switch (pin) {

        case PPC6xx_INPUT_TBEN:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: %s the time base\n",

                        __func__, level ? "start" : "stop");

            }

#endif

            if (level) {

                cpu_ppc_tb_start(env);

            } else {

                cpu_ppc_tb_stop(env);

            }

        case PPC6xx_INPUT_INT:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the external IRQ state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_EXT, level);

            break;

        case PPC6xx_INPUT_SMI:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the SMI IRQ state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_SMI, level);

            break;

        case PPC6xx_INPUT_MCP:

            /* Negative edge sensitive */

            /* XXX: TODO: actual reaction may depends on HID0 status

             *            603/604/740/750: check HID0[EMCP]

             */

            if (cur_level == 1 && level == 0) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: raise machine check state\n",

                            __func__);

                }

#endif

                ppc_set_irq(env, PPC_INTERRUPT_MCK, 1);

            }

            break;

        case PPC6xx_INPUT_CKSTP_IN:

            /* Level sensitive - active low */

            /* XXX: TODO: relay the signal to CKSTP_OUT pin */

            /* XXX: Note that the only way to restart the CPU is to reset it */

            if (level) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: stop the CPU\n", __func__);

                }

#endif

                env->halted = 1;

            }

            break;

        case PPC6xx_INPUT_HRESET:

            /* Level sensitive - active low */

            if (level) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: reset the CPU\n", __func__);

                }

#endif

                env->interrupt_request |= CPU_INTERRUPT_EXITTB;

                /* XXX: TOFIX */

#if 0

                cpu_ppc_reset(env);

#else

                qemu_system_reset_request();

#endif

            }

            break;

        case PPC6xx_INPUT_SRESET:

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the RESET IRQ state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_RESET, level);

            break;

        default:

            /* Unknown pin - do nothing */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: unknown IRQ pin %d\n", __func__, pin);

            }

#endif

            return;

        }

        if (level)

            env->irq_input_state |= 1 << pin;

        else

            env->irq_input_state &= ~(1 << pin);

    }

}

void ppc6xx_irq_init (CPUState *env)

{

    env->irq_inputs = (void **)qemu_allocate_irqs(&ppc6xx_set_irq, env,

                                                  PPC6xx_INPUT_NB);

}

#if defined(TARGET_PPC64)

/* PowerPC 970 internal IRQ controller */

static void ppc970_set_irq (void *opaque, int pin, int level)

{

    CPUState *env = opaque;

    int cur_level;

#if defined(PPC_DEBUG_IRQ)

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "%s: env %p pin %d level %d\n", __func__,

                env, pin, level);

    }

#endif

    cur_level = (env->irq_input_state >> pin) & 1;

    /* Don't generate spurious events */

    if ((cur_level == 1 && level == 0) || (cur_level == 0 && level != 0)) {

        switch (pin) {

        case PPC970_INPUT_INT:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the external IRQ state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_EXT, level);

            break;

        case PPC970_INPUT_THINT:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the SMI IRQ state to %d\n", __func__,

                        level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_THERM, level);

            break;

        case PPC970_INPUT_MCP:

            /* Negative edge sensitive */

            /* XXX: TODO: actual reaction may depends on HID0 status

             *            603/604/740/750: check HID0[EMCP]

             */

            if (cur_level == 1 && level == 0) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: raise machine check state\n",

                            __func__);

                }

#endif

                ppc_set_irq(env, PPC_INTERRUPT_MCK, 1);

            }

            break;

        case PPC970_INPUT_CKSTP:

            /* Level sensitive - active low */

            /* XXX: TODO: relay the signal to CKSTP_OUT pin */

            if (level) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: stop the CPU\n", __func__);

                }

#endif

                env->halted = 1;

            } else {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: restart the CPU\n", __func__);

                }

#endif

                env->halted = 0;

            }

            break;

        case PPC970_INPUT_HRESET:

            /* Level sensitive - active low */

            if (level) {

#if 0 // XXX: TOFIX

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: reset the CPU\n", __func__);

                }

#endif

                cpu_reset(env);

#endif

            }

            break;

        case PPC970_INPUT_SRESET:

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the RESET IRQ state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_RESET, level);

            break;

        case PPC970_INPUT_TBEN:

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the TBEN state to %d\n", __func__,

                        level);

            }

#endif

            /* XXX: TODO */

            break;

        default:

            /* Unknown pin - do nothing */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: unknown IRQ pin %d\n", __func__, pin);

            }

#endif

            return;

        }

        if (level)

            env->irq_input_state |= 1 << pin;

        else

            env->irq_input_state &= ~(1 << pin);

    }

}

void ppc970_irq_init (CPUState *env)

{

    env->irq_inputs = (void **)qemu_allocate_irqs(&ppc970_set_irq, env,

                                                  PPC970_INPUT_NB);

}

#endif /* defined(TARGET_PPC64) */

/* PowerPC 40x internal IRQ controller */

static void ppc40x_set_irq (void *opaque, int pin, int level)

{

    CPUState *env = opaque;

    int cur_level;

#if defined(PPC_DEBUG_IRQ)

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "%s: env %p pin %d level %d\n", __func__,

                env, pin, level);

    }

#endif

    cur_level = (env->irq_input_state >> pin) & 1;

    /* Don't generate spurious events */

    if ((cur_level == 1 && level == 0) || (cur_level == 0 && level != 0)) {

        switch (pin) {

        case PPC40x_INPUT_RESET_SYS:

            if (level) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: reset the PowerPC system\n",

                            __func__);

                }

#endif

                ppc40x_system_reset(env);

            }

            break;

        case PPC40x_INPUT_RESET_CHIP:

            if (level) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: reset the PowerPC chip\n", __func__);

                }

#endif

                ppc40x_chip_reset(env);

            }

            break;

        case PPC40x_INPUT_RESET_CORE:

            /* XXX: TODO: update DBSR[MRR] */

            if (level) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: reset the PowerPC core\n", __func__);

                }

#endif

                ppc40x_core_reset(env);

            }

            break;

        case PPC40x_INPUT_CINT:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the critical IRQ state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_CEXT, level);

            break;

        case PPC40x_INPUT_INT:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the external IRQ state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_EXT, level);

            break;

        case PPC40x_INPUT_HALT:

            /* Level sensitive - active low */

            if (level) {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: stop the CPU\n", __func__);

                }

#endif

                env->halted = 1;

            } else {

#if defined(PPC_DEBUG_IRQ)

                if (loglevel & CPU_LOG_INT) {

                    fprintf(logfile, "%s: restart the CPU\n", __func__);

                }

#endif

                env->halted = 0;

            }

            break;

        case PPC40x_INPUT_DEBUG:

            /* Level sensitive - active high */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: set the debug pin state to %d\n",

                        __func__, level);

            }

#endif

            ppc_set_irq(env, PPC_INTERRUPT_DEBUG, level);

            break;

        default:

            /* Unknown pin - do nothing */

#if defined(PPC_DEBUG_IRQ)

            if (loglevel & CPU_LOG_INT) {

                fprintf(logfile, "%s: unknown IRQ pin %d\n", __func__, pin);

            }

#endif

            return;

        }

        if (level)

            env->irq_input_state |= 1 << pin;

        else

            env->irq_input_state &= ~(1 << pin);

    }

}

void ppc40x_irq_init (CPUState *env)

{

    env->irq_inputs = (void **)qemu_allocate_irqs(&ppc40x_set_irq,

                                                  env, PPC40x_INPUT_NB);

}

/*****************************************************************************/

/* PowerPC time base and decrementer emulation */

struct ppc_tb_t {

    /* Time base management */

    int64_t  tb_offset;    /* Compensation                    */

    int64_t  atb_offset;   /* Compensation                    */

    uint32_t tb_freq;      /* TB frequency                    */

    /* Decrementer management */

    uint64_t decr_next;    /* Tick for next decr interrupt    */

    uint32_t decr_freq;    /* decrementer frequency           */

    struct QEMUTimer *decr_timer;

    /* Hypervisor decrementer management */

    uint64_t hdecr_next;    /* Tick for next hdecr interrupt  */

    struct QEMUTimer *hdecr_timer;

    uint64_t purr_load;

    uint64_t purr_start;

    void *opaque;

};

static always_inline uint64_t cpu_ppc_get_tb (ppc_tb_t *tb_env, uint64_t vmclk,

                                              int64_t tb_offset)

{

    /* TB time in tb periods */

    return muldiv64(vmclk, tb_env->tb_freq, ticks_per_sec) + tb_offset;

}

uint32_t cpu_ppc_load_tbl (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->tb_offset);

#if defined(PPC_DEBUG_TB)

    if (loglevel != 0) {

        fprintf(logfile, "%s: tb %016" PRIx64 "\n", __func__, tb);

    }

#endif

    return tb & 0xFFFFFFFF;

}

static always_inline uint32_t _cpu_ppc_load_tbu (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->tb_offset);

#if defined(PPC_DEBUG_TB)

    if (loglevel != 0) {

        fprintf(logfile, "%s: tb %016" PRIx64 "\n", __func__, tb);

    }

#endif

    return tb >> 32;

}

uint32_t cpu_ppc_load_tbu (CPUState *env)

{

    return _cpu_ppc_load_tbu(env);

}

static always_inline void cpu_ppc_store_tb (ppc_tb_t *tb_env, uint64_t vmclk,

                                            int64_t *tb_offsetp,

                                            uint64_t value)

{

    *tb_offsetp = value - muldiv64(vmclk, tb_env->tb_freq, ticks_per_sec);

#ifdef PPC_DEBUG_TB

    if (loglevel != 0) {

        fprintf(logfile, "%s: tb %016" PRIx64 " offset %08" PRIx64 "\n",

                __func__, value, *tb_offsetp);

    }

#endif

}

void cpu_ppc_store_tbl (CPUState *env, uint32_t value)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->tb_offset);

    tb &= 0xFFFFFFFF00000000ULL;

    cpu_ppc_store_tb(tb_env, qemu_get_clock(vm_clock),

                     &tb_env->tb_offset, tb | (uint64_t)value);

}

static always_inline void _cpu_ppc_store_tbu (CPUState *env, uint32_t value)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->tb_offset);

    tb &= 0x00000000FFFFFFFFULL;

    cpu_ppc_store_tb(tb_env, qemu_get_clock(vm_clock),

                     &tb_env->tb_offset, ((uint64_t)value << 32) | tb);

}

void cpu_ppc_store_tbu (CPUState *env, uint32_t value)

{

    _cpu_ppc_store_tbu(env, value);

}

uint32_t cpu_ppc_load_atbl (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->atb_offset);

#if defined(PPC_DEBUG_TB)

    if (loglevel != 0) {

        fprintf(logfile, "%s: tb %016" PRIx64 "\n", __func__, tb);

    }

#endif

    return tb & 0xFFFFFFFF;

}

uint32_t cpu_ppc_load_atbu (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->atb_offset);

#if defined(PPC_DEBUG_TB)

    if (loglevel != 0) {

        fprintf(logfile, "%s: tb %016" PRIx64 "\n", __func__, tb);

    }

#endif

    return tb >> 32;

}

void cpu_ppc_store_atbl (CPUState *env, uint32_t value)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->atb_offset);

    tb &= 0xFFFFFFFF00000000ULL;

    cpu_ppc_store_tb(tb_env, qemu_get_clock(vm_clock),

                     &tb_env->atb_offset, tb | (uint64_t)value);

}

void cpu_ppc_store_atbu (CPUState *env, uint32_t value)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb;

    tb = cpu_ppc_get_tb(tb_env, qemu_get_clock(vm_clock), tb_env->atb_offset);

    tb &= 0x00000000FFFFFFFFULL;

    cpu_ppc_store_tb(tb_env, qemu_get_clock(vm_clock),

                     &tb_env->atb_offset, ((uint64_t)value << 32) | tb);

}

static void cpu_ppc_tb_stop (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb, atb, vmclk;

    /* If the time base is already frozen, do nothing */

    if (tb_env->tb_freq != 0) {

        vmclk = qemu_get_clock(vm_clock);

        /* Get the time base */

        tb = cpu_ppc_get_tb(tb_env, vmclk, tb_env->tb_offset);

        /* Get the alternate time base */

        atb = cpu_ppc_get_tb(tb_env, vmclk, tb_env->atb_offset);

        /* Store the time base value (ie compute the current offset) */

        cpu_ppc_store_tb(tb_env, vmclk, &tb_env->tb_offset, tb);

        /* Store the alternate time base value (compute the current offset) */

        cpu_ppc_store_tb(tb_env, vmclk, &tb_env->atb_offset, atb);

        /* Set the time base frequency to zero */

        tb_env->tb_freq = 0;

        /* Now, the time bases are frozen to tb_offset / atb_offset value */

    }

}

static void cpu_ppc_tb_start (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t tb, atb, vmclk;

    /* If the time base is not frozen, do nothing */

    if (tb_env->tb_freq == 0) {

        vmclk = qemu_get_clock(vm_clock);

        /* Get the time base from tb_offset */

        tb = tb_env->tb_offset;

        /* Get the alternate time base from atb_offset */

        atb = tb_env->atb_offset;

        /* Restore the tb frequency from the decrementer frequency */

        tb_env->tb_freq = tb_env->decr_freq;

        /* Store the time base value */

        cpu_ppc_store_tb(tb_env, vmclk, &tb_env->tb_offset, tb);

        /* Store the alternate time base value */

        cpu_ppc_store_tb(tb_env, vmclk, &tb_env->atb_offset, atb);

    }

}

static always_inline uint32_t _cpu_ppc_load_decr (CPUState *env,

                                                  uint64_t *next)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint32_t decr;

    int64_t diff;

    diff = tb_env->decr_next - qemu_get_clock(vm_clock);

    if (diff >= 0)

        decr = muldiv64(diff, tb_env->decr_freq, ticks_per_sec);

    else

        decr = -muldiv64(-diff, tb_env->decr_freq, ticks_per_sec);

#if defined(PPC_DEBUG_TB)

    if (loglevel != 0) {

        fprintf(logfile, "%s: %08" PRIx32 "\n", __func__, decr);

    }

#endif

    return decr;

}

uint32_t cpu_ppc_load_decr (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    return _cpu_ppc_load_decr(env, &tb_env->decr_next);

}

uint32_t cpu_ppc_load_hdecr (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    return _cpu_ppc_load_decr(env, &tb_env->hdecr_next);

}

uint64_t cpu_ppc_load_purr (CPUState *env)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t diff;

    diff = qemu_get_clock(vm_clock) - tb_env->purr_start;

    return tb_env->purr_load + muldiv64(diff, tb_env->tb_freq, ticks_per_sec);

}

/* When decrementer expires,

 * all we need to do is generate or queue a CPU exception

 */

static always_inline void cpu_ppc_decr_excp (CPUState *env)

{

    /* Raise it */

#ifdef PPC_DEBUG_TB

    if (loglevel != 0) {

        fprintf(logfile, "raise decrementer exception\n");

    }

#endif

    ppc_set_irq(env, PPC_INTERRUPT_DECR, 1);

}

static always_inline void cpu_ppc_hdecr_excp (CPUState *env)

{

    /* Raise it */

#ifdef PPC_DEBUG_TB

    if (loglevel != 0) {

        fprintf(logfile, "raise decrementer exception\n");

    }

#endif

    ppc_set_irq(env, PPC_INTERRUPT_HDECR, 1);

}

static void __cpu_ppc_store_decr (CPUState *env, uint64_t *nextp,

                                  struct QEMUTimer *timer,

                                  void (*raise_excp)(CPUState *),

                                  uint32_t decr, uint32_t value,

                                  int is_excp)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t now, next;

#ifdef PPC_DEBUG_TB

    if (loglevel != 0) {

        fprintf(logfile, "%s: %08" PRIx32 " => %08" PRIx32 "\n", __func__,

                decr, value);

    }

#endif

    now = qemu_get_clock(vm_clock);

    next = now + muldiv64(value, ticks_per_sec, tb_env->decr_freq);

    if (is_excp)

        next += *nextp - now;

    if (next == now)

        next++;

    *nextp = next;

    /* Adjust timer */

    qemu_mod_timer(timer, next);

    /* If we set a negative value and the decrementer was positive,

     * raise an exception.

     */

    if ((value & 0x80000000) && !(decr & 0x80000000))

        (*raise_excp)(env);

}

static always_inline void _cpu_ppc_store_decr (CPUState *env, uint32_t decr,

                                               uint32_t value, int is_excp)

{

    ppc_tb_t *tb_env = env->tb_env;

    __cpu_ppc_store_decr(env, &tb_env->decr_next, tb_env->decr_timer,

                         &cpu_ppc_decr_excp, decr, value, is_excp);

}

void cpu_ppc_store_decr (CPUState *env, uint32_t value)

{

    _cpu_ppc_store_decr(env, cpu_ppc_load_decr(env), value, 0);

}

static void cpu_ppc_decr_cb (void *opaque)

{

    _cpu_ppc_store_decr(opaque, 0x00000000, 0xFFFFFFFF, 1);

}

static always_inline void _cpu_ppc_store_hdecr (CPUState *env, uint32_t hdecr,

                                                uint32_t value, int is_excp)

{

    ppc_tb_t *tb_env = env->tb_env;

    if (tb_env->hdecr_timer != NULL) {

        __cpu_ppc_store_decr(env, &tb_env->hdecr_next, tb_env->hdecr_timer,

                             &cpu_ppc_hdecr_excp, hdecr, value, is_excp);

    }

}

void cpu_ppc_store_hdecr (CPUState *env, uint32_t value)

{

    _cpu_ppc_store_hdecr(env, cpu_ppc_load_hdecr(env), value, 0);

}

static void cpu_ppc_hdecr_cb (void *opaque)

{

    _cpu_ppc_store_hdecr(opaque, 0x00000000, 0xFFFFFFFF, 1);

}

void cpu_ppc_store_purr (CPUState *env, uint64_t value)

{

    ppc_tb_t *tb_env = env->tb_env;

    tb_env->purr_load = value;

    tb_env->purr_start = qemu_get_clock(vm_clock);

}

static void cpu_ppc_set_tb_clk (void *opaque, uint32_t freq)

{

    CPUState *env = opaque;

    ppc_tb_t *tb_env = env->tb_env;

    tb_env->tb_freq = freq;

    tb_env->decr_freq = freq;

    /* There is a bug in Linux 2.4 kernels:

     * if a decrementer exception is pending when it enables msr_ee at startup,

     * it's not ready to handle it...

     */

    _cpu_ppc_store_decr(env, 0xFFFFFFFF, 0xFFFFFFFF, 0);

    _cpu_ppc_store_hdecr(env, 0xFFFFFFFF, 0xFFFFFFFF, 0);

    cpu_ppc_store_purr(env, 0x0000000000000000ULL);

}

/* Set up (once) timebase frequency (in Hz) */

clk_setup_cb cpu_ppc_tb_init (CPUState *env, uint32_t freq)

{

    ppc_tb_t *tb_env;

    tb_env = qemu_mallocz(sizeof(ppc_tb_t));

    if (tb_env == NULL)

        return NULL;

    env->tb_env = tb_env;

    /* Create new timer */

    tb_env->decr_timer = qemu_new_timer(vm_clock, &cpu_ppc_decr_cb, env);

    if (0) {

        /* XXX: find a suitable condition to enable the hypervisor decrementer

         */

        tb_env->hdecr_timer = qemu_new_timer(vm_clock, &cpu_ppc_hdecr_cb, env);

    } else {

        tb_env->hdecr_timer = NULL;

    }

    cpu_ppc_set_tb_clk(env, freq);

    return &cpu_ppc_set_tb_clk;

}

/* Specific helpers for POWER & PowerPC 601 RTC */

clk_setup_cb cpu_ppc601_rtc_init (CPUState *env)

{

    return cpu_ppc_tb_init(env, 7812500);

}

void cpu_ppc601_store_rtcu (CPUState *env, uint32_t value)

{

    _cpu_ppc_store_tbu(env, value);

}

uint32_t cpu_ppc601_load_rtcu (CPUState *env)

{

    return _cpu_ppc_load_tbu(env);

}

void cpu_ppc601_store_rtcl (CPUState *env, uint32_t value)

{

    cpu_ppc_store_tbl(env, value & 0x3FFFFF80);

}

uint32_t cpu_ppc601_load_rtcl (CPUState *env)

{

    return cpu_ppc_load_tbl(env) & 0x3FFFFF80;

}

/*****************************************************************************/

/* Embedded PowerPC timers */

/* PIT, FIT & WDT */

typedef struct ppcemb_timer_t ppcemb_timer_t;

struct ppcemb_timer_t {

    uint64_t pit_reload;  /* PIT auto-reload value        */

    uint64_t fit_next;    /* Tick for next FIT interrupt  */

    struct QEMUTimer *fit_timer;

    uint64_t wdt_next;    /* Tick for next WDT interrupt  */

    struct QEMUTimer *wdt_timer;

};

/* Fixed interval timer */

static void cpu_4xx_fit_cb (void *opaque)

{

    CPUState *env;

    ppc_tb_t *tb_env;

    ppcemb_timer_t *ppcemb_timer;

    uint64_t now, next;

    env = opaque;

    tb_env = env->tb_env;

    ppcemb_timer = tb_env->opaque;

    now = qemu_get_clock(vm_clock);

    switch ((env->spr[SPR_40x_TCR] >> 24) & 0x3) {

    case 0:

        next = 1 << 9;

        break;

    case 1:

        next = 1 << 13;

        break;

    case 2:

        next = 1 << 17;

        break;

    case 3:

        next = 1 << 21;

        break;

    default:

        /* Cannot occur, but makes gcc happy */

        return;

    }

    next = now + muldiv64(next, ticks_per_sec, tb_env->tb_freq);

    if (next == now)

        next++;

    qemu_mod_timer(ppcemb_timer->fit_timer, next);

    env->spr[SPR_40x_TSR] |= 1 << 26;

    if ((env->spr[SPR_40x_TCR] >> 23) & 0x1)

        ppc_set_irq(env, PPC_INTERRUPT_FIT, 1);

#ifdef PPC_DEBUG_TB

    if (loglevel != 0) {

        fprintf(logfile, "%s: ir %d TCR " ADDRX " TSR " ADDRX "\n", __func__,

                (int)((env->spr[SPR_40x_TCR] >> 23) & 0x1),

                env->spr[SPR_40x_TCR], env->spr[SPR_40x_TSR]);

    }