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/*

 * QEMU M48T59 and M48T08 NVRAM emulation for PPC PREP and Sparc platforms

 *

 * Copyright (c) 2003-2005, 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 "nvram.h"

#include "isa.h"

#include "qemu-timer.h"

#include "sysemu.h"

//#define DEBUG_NVRAM

#if defined(DEBUG_NVRAM)

#define NVRAM_PRINTF(fmt, args...) do { printf(fmt , ##args); } while (0)

#else

#define NVRAM_PRINTF(fmt, args...) do { } while (0)

#endif

/*

 * The M48T02, M48T08 and M48T59 chips are very similar. The newer '59 has

 * alarm and a watchdog timer and related control registers. In the

 * PPC platform there is also a nvram lock function.

 */

struct m48t59_t {

    /* Model parameters */

    int type; // 2 = m48t02, 8 = m48t08, 59 = m48t59

    /* Hardware parameters */

    qemu_irq IRQ;

    int mem_index;

    uint32_t io_base;

    uint16_t size;

    /* RTC management */

    time_t   time_offset;

    time_t   stop_time;

    /* Alarm & watchdog */

    struct tm alarm;

    struct QEMUTimer *alrm_timer;

    struct QEMUTimer *wd_timer;

    /* NVRAM storage */

    uint8_t  lock;

    uint16_t addr;

    uint8_t *buffer;

};

/* Fake timer functions */

/* Generic helpers for BCD */

static inline uint8_t toBCD (uint8_t value)

{

    return (((value / 10) % 10) << 4) | (value % 10);

}

static inline uint8_t fromBCD (uint8_t BCD)

{

    return ((BCD >> 4) * 10) + (BCD & 0x0F);

}

/* Alarm management */

static void alarm_cb (void *opaque)

{

    struct tm tm;

    uint64_t next_time;

    m48t59_t *NVRAM = opaque;

    qemu_set_irq(NVRAM->IRQ, 1);

    if ((NVRAM->buffer[0x1FF5] & 0x80) == 0 &&

        (NVRAM->buffer[0x1FF4] & 0x80) == 0 &&

        (NVRAM->buffer[0x1FF3] & 0x80) == 0 &&

        (NVRAM->buffer[0x1FF2] & 0x80) == 0) {

        /* Repeat once a month */

        qemu_get_timedate(&tm, NVRAM->time_offset);

        tm.tm_mon++;

        if (tm.tm_mon == 13) {

            tm.tm_mon = 1;

            tm.tm_year++;

        }

        next_time = qemu_timedate_diff(&tm) - NVRAM->time_offset;

    } else if ((NVRAM->buffer[0x1FF5] & 0x80) != 0 &&

               (NVRAM->buffer[0x1FF4] & 0x80) == 0 &&

               (NVRAM->buffer[0x1FF3] & 0x80) == 0 &&

               (NVRAM->buffer[0x1FF2] & 0x80) == 0) {

        /* Repeat once a day */

        next_time = 24 * 60 * 60;

    } else if ((NVRAM->buffer[0x1FF5] & 0x80) != 0 &&

               (NVRAM->buffer[0x1FF4] & 0x80) != 0 &&

               (NVRAM->buffer[0x1FF3] & 0x80) == 0 &&

               (NVRAM->buffer[0x1FF2] & 0x80) == 0) {

        /* Repeat once an hour */

        next_time = 60 * 60;

    } else if ((NVRAM->buffer[0x1FF5] & 0x80) != 0 &&

               (NVRAM->buffer[0x1FF4] & 0x80) != 0 &&

               (NVRAM->buffer[0x1FF3] & 0x80) != 0 &&

               (NVRAM->buffer[0x1FF2] & 0x80) == 0) {

        /* Repeat once a minute */

        next_time = 60;

    } else {

        /* Repeat once a second */

        next_time = 1;

    }

    qemu_mod_timer(NVRAM->alrm_timer, qemu_get_clock(vm_clock) +

                    next_time * 1000);

    qemu_set_irq(NVRAM->IRQ, 0);

}

static void set_alarm (m48t59_t *NVRAM)

{

    int diff;

    if (NVRAM->alrm_timer != NULL) {

        qemu_del_timer(NVRAM->alrm_timer);

        diff = qemu_timedate_diff(&NVRAM->alarm) - NVRAM->time_offset;

        if (diff > 0)

            qemu_mod_timer(NVRAM->alrm_timer, diff * 1000);

    }

}

/* RTC management helpers */

static inline void get_time (m48t59_t *NVRAM, struct tm *tm)

{

    qemu_get_timedate(tm, NVRAM->time_offset);

}

static void set_time (m48t59_t *NVRAM, struct tm *tm)

{

    NVRAM->time_offset = qemu_timedate_diff(tm);

    set_alarm(NVRAM);

}

/* Watchdog management */

static void watchdog_cb (void *opaque)

{

    m48t59_t *NVRAM = opaque;

    NVRAM->buffer[0x1FF0] |= 0x80;

    if (NVRAM->buffer[0x1FF7] & 0x80) {

        NVRAM->buffer[0x1FF7] = 0x00;

        NVRAM->buffer[0x1FFC] &= ~0x40;

        /* May it be a hw CPU Reset instead ? */

        qemu_system_reset_request();

    } else {

        qemu_set_irq(NVRAM->IRQ, 1);

        qemu_set_irq(NVRAM->IRQ, 0);

    }

}

static void set_up_watchdog (m48t59_t *NVRAM, uint8_t value)

{

    uint64_t interval; /* in 1/16 seconds */

    NVRAM->buffer[0x1FF0] &= ~0x80;

    if (NVRAM->wd_timer != NULL) {

        qemu_del_timer(NVRAM->wd_timer);

        if (value != 0) {

            interval = (1 << (2 * (value & 0x03))) * ((value >> 2) & 0x1F);

            qemu_mod_timer(NVRAM->wd_timer, ((uint64_t)time(NULL) * 1000) +

                           ((interval * 1000) >> 4));

        }

    }

}

/* Direct access to NVRAM */

void m48t59_write (void *opaque, uint32_t addr, uint32_t val)

{

    m48t59_t *NVRAM = opaque;

    struct tm tm;

    int tmp;

    if (addr > 0x1FF8 && addr < 0x2000)

        NVRAM_PRINTF("%s: 0x%08x => 0x%08x\n", __func__, addr, val);

    /* check for NVRAM access */

    if ((NVRAM->type == 2 && addr < 0x7f8) ||

        (NVRAM->type == 8 && addr < 0x1ff8) ||

        (NVRAM->type == 59 && addr < 0x1ff0))

        goto do_write;

    /* TOD access */

    switch (addr) {

    case 0x1FF0:

        /* flags register : read-only */

        break;

    case 0x1FF1:

        /* unused */

        break;

    case 0x1FF2:

        /* alarm seconds */

        tmp = fromBCD(val & 0x7F);

        if (tmp >= 0 && tmp <= 59) {

            NVRAM->alarm.tm_sec = tmp;

            NVRAM->buffer[0x1FF2] = val;

            set_alarm(NVRAM);

        }

        break;

    case 0x1FF3:

        /* alarm minutes */

        tmp = fromBCD(val & 0x7F);

        if (tmp >= 0 && tmp <= 59) {

            NVRAM->alarm.tm_min = tmp;

            NVRAM->buffer[0x1FF3] = val;

            set_alarm(NVRAM);

        }

        break;

    case 0x1FF4:

        /* alarm hours */

        tmp = fromBCD(val & 0x3F);

        if (tmp >= 0 && tmp <= 23) {

            NVRAM->alarm.tm_hour = tmp;

            NVRAM->buffer[0x1FF4] = val;

            set_alarm(NVRAM);

        }

        break;

    case 0x1FF5:

        /* alarm date */

        tmp = fromBCD(val & 0x1F);

        if (tmp != 0) {

            NVRAM->alarm.tm_mday = tmp;

            NVRAM->buffer[0x1FF5] = val;

            set_alarm(NVRAM);

        }

        break;

    case 0x1FF6:

        /* interrupts */

        NVRAM->buffer[0x1FF6] = val;

        break;

    case 0x1FF7:

        /* watchdog */

        NVRAM->buffer[0x1FF7] = val;

        set_up_watchdog(NVRAM, val);

        break;

    case 0x1FF8:

    case 0x07F8:

        /* control */

       NVRAM->buffer[addr] = (val & ~0xA0) | 0x90;

        break;

    case 0x1FF9:

    case 0x07F9:

        /* seconds (BCD) */

        tmp = fromBCD(val & 0x7F);

        if (tmp >= 0 && tmp <= 59) {

            get_time(NVRAM, &tm);

            tm.tm_sec = tmp;

            set_time(NVRAM, &tm);

        }

        if ((val & 0x80) ^ (NVRAM->buffer[addr] & 0x80)) {

            if (val & 0x80) {

                NVRAM->stop_time = time(NULL);

            } else {

                NVRAM->time_offset += NVRAM->stop_time - time(NULL);

                NVRAM->stop_time = 0;

            }

        }

        NVRAM->buffer[addr] = val & 0x80;

        break;

    case 0x1FFA:

    case 0x07FA:

        /* minutes (BCD) */

        tmp = fromBCD(val & 0x7F);

        if (tmp >= 0 && tmp <= 59) {

            get_time(NVRAM, &tm);

            tm.tm_min = tmp;

            set_time(NVRAM, &tm);

        }

        break;

    case 0x1FFB:

    case 0x07FB:

        /* hours (BCD) */

        tmp = fromBCD(val & 0x3F);

        if (tmp >= 0 && tmp <= 23) {

            get_time(NVRAM, &tm);

            tm.tm_hour = tmp;

            set_time(NVRAM, &tm);

        }

        break;

    case 0x1FFC:

    case 0x07FC:

        /* day of the week / century */

        tmp = fromBCD(val & 0x07);

        get_time(NVRAM, &tm);

        tm.tm_wday = tmp;

        set_time(NVRAM, &tm);

        NVRAM->buffer[addr] = val & 0x40;

        break;

    case 0x1FFD:

    case 0x07FD:

        /* date */

        tmp = fromBCD(val & 0x1F);

        if (tmp != 0) {

            get_time(NVRAM, &tm);

            tm.tm_mday = tmp;

            set_time(NVRAM, &tm);

        }

        break;

    case 0x1FFE:

    case 0x07FE:

        /* month */

        tmp = fromBCD(val & 0x1F);

        if (tmp >= 1 && tmp <= 12) {

            get_time(NVRAM, &tm);

            tm.tm_mon = tmp - 1;

            set_time(NVRAM, &tm);

        }

        break;

    case 0x1FFF:

    case 0x07FF:

        /* year */

        tmp = fromBCD(val);

        if (tmp >= 0 && tmp <= 99) {

            get_time(NVRAM, &tm);

            if (NVRAM->type == 8)

                tm.tm_year = fromBCD(val) + 68; // Base year is 1968

            else

                tm.tm_year = fromBCD(val);

            set_time(NVRAM, &tm);

        }

        break;

    default:

        /* Check lock registers state */

        if (addr >= 0x20 && addr <= 0x2F && (NVRAM->lock & 1))

            break;

        if (addr >= 0x30 && addr <= 0x3F && (NVRAM->lock & 2))

            break;

    do_write:

        if (addr < NVRAM->size) {

            NVRAM->buffer[addr] = val & 0xFF;

        }

        break;

    }

}

uint32_t m48t59_read (void *opaque, uint32_t addr)

{

    m48t59_t *NVRAM = opaque;

    struct tm tm;

    uint32_t retval = 0xFF;

    /* check for NVRAM access */

    if ((NVRAM->type == 2 && addr < 0x078f) ||

        (NVRAM->type == 8 && addr < 0x1ff8) ||

        (NVRAM->type == 59 && addr < 0x1ff0))

        goto do_read;

    /* TOD access */

    switch (addr) {

    case 0x1FF0:

        /* flags register */

        goto do_read;

    case 0x1FF1:

        /* unused */

        retval = 0;

        break;

    case 0x1FF2:

        /* alarm seconds */

        goto do_read;

    case 0x1FF3:

        /* alarm minutes */

        goto do_read;

    case 0x1FF4:

        /* alarm hours */

        goto do_read;

    case 0x1FF5:

        /* alarm date */

        goto do_read;

    case 0x1FF6:

        /* interrupts */

        goto do_read;

    case 0x1FF7:

        /* A read resets the watchdog */

        set_up_watchdog(NVRAM, NVRAM->buffer[0x1FF7]);

        goto do_read;

    case 0x1FF8:

    case 0x07F8:

        /* control */

        goto do_read;

    case 0x1FF9:

    case 0x07F9:

        /* seconds (BCD) */

        get_time(NVRAM, &tm);

        retval = (NVRAM->buffer[addr] & 0x80) | toBCD(tm.tm_sec);

        break;

    case 0x1FFA:

    case 0x07FA:

        /* minutes (BCD) */

        get_time(NVRAM, &tm);

        retval = toBCD(tm.tm_min);

        break;

    case 0x1FFB:

    case 0x07FB:

        /* hours (BCD) */

        get_time(NVRAM, &tm);

        retval = toBCD(tm.tm_hour);

        break;

    case 0x1FFC:

    case 0x07FC:

        /* day of the week / century */

        get_time(NVRAM, &tm);

        retval = NVRAM->buffer[addr] | tm.tm_wday;

        break;

    case 0x1FFD:

    case 0x07FD:

        /* date */

        get_time(NVRAM, &tm);

        retval = toBCD(tm.tm_mday);

        break;

    case 0x1FFE:

    case 0x07FE:

        /* month */

        get_time(NVRAM, &tm);

        retval = toBCD(tm.tm_mon + 1);

        break;

    case 0x1FFF:

    case 0x07FF:

        /* year */

        get_time(NVRAM, &tm);

        if (NVRAM->type == 8)

            retval = toBCD(tm.tm_year - 68); // Base year is 1968

        else

            retval = toBCD(tm.tm_year);

        break;

    default:

        /* Check lock registers state */

        if (addr >= 0x20 && addr <= 0x2F && (NVRAM->lock & 1))

            break;

        if (addr >= 0x30 && addr <= 0x3F && (NVRAM->lock & 2))

            break;

    do_read:

        if (addr < NVRAM->size) {

            retval = NVRAM->buffer[addr];

        }

        break;

    }

    if (addr > 0x1FF9 && addr < 0x2000)

       NVRAM_PRINTF("%s: 0x%08x <= 0x%08x\n", __func__, addr, retval);

    return retval;

}

void m48t59_set_addr (void *opaque, uint32_t addr)

{

    m48t59_t *NVRAM = opaque;

    NVRAM->addr = addr;

}

void m48t59_toggle_lock (void *opaque, int lock)

{

    m48t59_t *NVRAM = opaque;

    NVRAM->lock ^= 1 << lock;

}

/* IO access to NVRAM */

static void NVRAM_writeb (void *opaque, uint32_t addr, uint32_t val)

{

    m48t59_t *NVRAM = opaque;

    addr -= NVRAM->io_base;

    NVRAM_PRINTF("%s: 0x%08x => 0x%08x\n", __func__, addr, val);

    switch (addr) {

    case 0:

        NVRAM->addr &= ~0x00FF;

        NVRAM->addr |= val;

        break;

    case 1:

        NVRAM->addr &= ~0xFF00;

        NVRAM->addr |= val << 8;

        break;

    case 3:

        m48t59_write(NVRAM, val, NVRAM->addr);

        NVRAM->addr = 0x0000;

        break;

    default:

        break;

    }

}

static uint32_t NVRAM_readb (void *opaque, uint32_t addr)

{

    m48t59_t *NVRAM = opaque;

    uint32_t retval;

    addr -= NVRAM->io_base;

    switch (addr) {

    case 3:

        retval = m48t59_read(NVRAM, NVRAM->addr);

        break;

    default:

        retval = -1;

        break;

    }

    NVRAM_PRINTF("%s: 0x%08x <= 0x%08x\n", __func__, addr, retval);

    return retval;

}

static void nvram_writeb (void *opaque, target_phys_addr_t addr, uint32_t value)

{

    m48t59_t *NVRAM = opaque;

    m48t59_write(NVRAM, addr, value & 0xff);

}

static void nvram_writew (void *opaque, target_phys_addr_t addr, uint32_t value)

{

    m48t59_t *NVRAM = opaque;

    m48t59_write(NVRAM, addr, (value >> 8) & 0xff);

    m48t59_write(NVRAM, addr + 1, value & 0xff);

}

static void nvram_writel (void *opaque, target_phys_addr_t addr, uint32_t value)

{

    m48t59_t *NVRAM = opaque;

    m48t59_write(NVRAM, addr, (value >> 24) & 0xff);

    m48t59_write(NVRAM, addr + 1, (value >> 16) & 0xff);

    m48t59_write(NVRAM, addr + 2, (value >> 8) & 0xff);

    m48t59_write(NVRAM, addr + 3, value & 0xff);

}

static uint32_t nvram_readb (void *opaque, target_phys_addr_t addr)

{

    m48t59_t *NVRAM = opaque;

    uint32_t retval;

    retval = m48t59_read(NVRAM, addr);

    return retval;

}

static uint32_t nvram_readw (void *opaque, target_phys_addr_t addr)

{

    m48t59_t *NVRAM = opaque;

    uint32_t retval;

    retval = m48t59_read(NVRAM, addr) << 8;

    retval |= m48t59_read(NVRAM, addr + 1);

    return retval;

}

static uint32_t nvram_readl (void *opaque, target_phys_addr_t addr)

{

    m48t59_t *NVRAM = opaque;

    uint32_t retval;

    retval = m48t59_read(NVRAM, addr) << 24;

    retval |= m48t59_read(NVRAM, addr + 1) << 16;

    retval |= m48t59_read(NVRAM, addr + 2) << 8;

    retval |= m48t59_read(NVRAM, addr + 3);

    return retval;

}

static CPUWriteMemoryFunc *nvram_write[] = {

    &nvram_writeb,

    &nvram_writew,

    &nvram_writel,

};

static CPUReadMemoryFunc *nvram_read[] = {

    &nvram_readb,

    &nvram_readw,

    &nvram_readl,

};

static void m48t59_save(QEMUFile *f, void *opaque)

{

    m48t59_t *s = opaque;

    qemu_put_8s(f, &s->lock);

    qemu_put_be16s(f, &s->addr);

    qemu_put_buffer(f, s->buffer, s->size);

}

static int m48t59_load(QEMUFile *f, void *opaque, int version_id)

{

    m48t59_t *s = opaque;

    if (version_id != 1)

        return -EINVAL;

    qemu_get_8s(f, &s->lock);

    qemu_get_be16s(f, &s->addr);

    qemu_get_buffer(f, s->buffer, s->size);

    return 0;

}

static void m48t59_reset(void *opaque)

{

    m48t59_t *NVRAM = opaque;

    NVRAM->addr = 0;

    NVRAM->lock = 0;

    if (NVRAM->alrm_timer != NULL)

        qemu_del_timer(NVRAM->alrm_timer);

    if (NVRAM->wd_timer != NULL)

        qemu_del_timer(NVRAM->wd_timer);

}

/* Initialisation routine */

m48t59_t *m48t59_init (qemu_irq IRQ, target_phys_addr_t mem_base,

                       uint32_t io_base, uint16_t size,

                       int type)

{

    m48t59_t *s;

    target_phys_addr_t save_base;

    s = qemu_mallocz(sizeof(m48t59_t));

    s->buffer = qemu_mallocz(size);

    s->IRQ = IRQ;

    s->size = size;

    s->io_base = io_base;

    s->type = type;

    if (io_base != 0) {

        register_ioport_read(io_base, 0x04, 1, NVRAM_readb, s);

        register_ioport_write(io_base, 0x04, 1, NVRAM_writeb, s);

    }

    if (mem_base != 0) {

        s->mem_index = cpu_register_io_memory(0, nvram_read, nvram_write, s);

        cpu_register_physical_memory(mem_base, size, s->mem_index);

    }

    if (type == 59) {

        s->alrm_timer = qemu_new_timer(vm_clock, &alarm_cb, s);

        s->wd_timer = qemu_new_timer(vm_clock, &watchdog_cb, s);

    }

    qemu_get_timedate(&s->alarm, 0);

    qemu_register_reset(m48t59_reset, s);

    save_base = mem_base ? mem_base : io_base;

    register_savevm("m48t59", save_base, 1, m48t59_save, m48t59_load, s);

    return s;

}