/*
 * QEMU CUDA support
 * 
 * Copyright (c) 2004 Fabrice Bellard
 * 
 * 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 "vl.h"

/* XXX: implement all timer modes */

//#define DEBUG_CUDA
//#define DEBUG_CUDA_PACKET

/* Bits in B data register: all active low */
#define TREQ		0x08		/* Transfer request (input) */
#define TACK		0x10		/* Transfer acknowledge (output) */
#define TIP		0x20		/* Transfer in progress (output) */

/* Bits in ACR */
#define SR_CTRL		0x1c		/* Shift register control bits */
#define SR_EXT		0x0c		/* Shift on external clock */
#define SR_OUT		0x10		/* Shift out if 1 */

/* Bits in IFR and IER */
#define IER_SET		0x80		/* set bits in IER */
#define IER_CLR		0		/* clear bits in IER */
#define SR_INT		0x04		/* Shift register full/empty */
#define T1_INT          0x40            /* Timer 1 interrupt */
#define T2_INT          0x20            /* Timer 2 interrupt */

/* Bits in ACR */
#define T1MODE          0xc0            /* Timer 1 mode */
#define T1MODE_CONT     0x40            /*  continuous interrupts */

/* commands (1st byte) */
#define ADB_PACKET	0
#define CUDA_PACKET	1
#define ERROR_PACKET	2
#define TIMER_PACKET	3
#define POWER_PACKET	4
#define MACIIC_PACKET	5
#define PMU_PACKET	6


/* CUDA commands (2nd byte) */
#define CUDA_WARM_START			0x0
#define CUDA_AUTOPOLL			0x1
#define CUDA_GET_6805_ADDR		0x2
#define CUDA_GET_TIME			0x3
#define CUDA_GET_PRAM			0x7
#define CUDA_SET_6805_ADDR		0x8
#define CUDA_SET_TIME			0x9
#define CUDA_POWERDOWN			0xa
#define CUDA_POWERUP_TIME		0xb
#define CUDA_SET_PRAM			0xc
#define CUDA_MS_RESET			0xd
#define CUDA_SEND_DFAC			0xe
#define CUDA_BATTERY_SWAP_SENSE		0x10
#define CUDA_RESET_SYSTEM		0x11
#define CUDA_SET_IPL			0x12
#define CUDA_FILE_SERVER_FLAG		0x13
#define CUDA_SET_AUTO_RATE		0x14
#define CUDA_GET_AUTO_RATE		0x16
#define CUDA_SET_DEVICE_LIST		0x19
#define CUDA_GET_DEVICE_LIST		0x1a
#define CUDA_SET_ONE_SECOND_MODE	0x1b
#define CUDA_SET_POWER_MESSAGES		0x21
#define CUDA_GET_SET_IIC		0x22
#define CUDA_WAKEUP			0x23
#define CUDA_TIMER_TICKLE		0x24
#define CUDA_COMBINED_FORMAT_IIC	0x25

#define CUDA_TIMER_FREQ (4700000 / 6)
#define CUDA_ADB_POLL_FREQ 50

/* CUDA returns time_t's offset from Jan 1, 1904, not 1970 */
#define RTC_OFFSET                      2082844800

typedef struct CUDATimer {
    int index; 
    uint16_t latch;
    uint16_t counter_value; /* counter value at load time */
    int64_t load_time;
    int64_t next_irq_time;
    QEMUTimer *timer;
} CUDATimer;

typedef struct CUDAState {
    /* cuda registers */
    uint8_t b;      /* B-side data */
    uint8_t a;      /* A-side data */
    uint8_t dirb;   /* B-side direction (1=output) */
    uint8_t dira;   /* A-side direction (1=output) */
    uint8_t sr;     /* Shift register */
    uint8_t acr;    /* Auxiliary control register */
    uint8_t pcr;    /* Peripheral control register */
    uint8_t ifr;    /* Interrupt flag register */
    uint8_t ier;    /* Interrupt enable register */
    uint8_t anh;    /* A-side data, no handshake */

    CUDATimer timers[2];
    
    uint8_t last_b; /* last value of B register */
    uint8_t last_acr; /* last value of B register */
    
    int data_in_size;
    int data_in_index;
    int data_out_index;

    qemu_irq irq;
    uint8_t autopoll;
    uint8_t data_in[128];
    uint8_t data_out[16];
    QEMUTimer *adb_poll_timer;
} CUDAState;

static CUDAState cuda_state;
ADBBusState adb_bus;

static void cuda_update(CUDAState *s);
static void cuda_receive_packet_from_host(CUDAState *s, 
                                          const uint8_t *data, int len);
static void cuda_timer_update(CUDAState *s, CUDATimer *ti, 
                              int64_t current_time);

static void cuda_update_irq(CUDAState *s)
{
    if (s->ifr & s->ier & (SR_INT | T1_INT)) {
        qemu_irq_raise(s->irq);
    } else {
        qemu_irq_lower(s->irq);
    }
}

static unsigned int get_counter(CUDATimer *s)
{
    int64_t d;
    unsigned int counter;

    d = muldiv64(qemu_get_clock(vm_clock) - s->load_time, 
                 CUDA_TIMER_FREQ, ticks_per_sec);
    if (s->index == 0) {
        /* the timer goes down from latch to -1 (period of latch + 2) */
        if (d <= (s->counter_value + 1)) {
            counter = (s->counter_value - d) & 0xffff;
        } else {
            counter = (d - (s->counter_value + 1)) % (s->latch + 2);
            counter = (s->latch - counter) & 0xffff; 
        }
    } else {
        counter = (s->counter_value - d) & 0xffff;
    }
    return counter;
}

static void set_counter(CUDAState *s, CUDATimer *ti, unsigned int val)
{
#ifdef DEBUG_CUDA
    printf("cuda: T%d.counter=%d\n",
           1 + (ti->timer == NULL), val);
#endif
    ti->load_time = qemu_get_clock(vm_clock);
    ti->counter_value = val;
    cuda_timer_update(s, ti, ti->load_time);
}

static int64_t get_next_irq_time(CUDATimer *s, int64_t current_time)
{
    int64_t d, next_time;
    unsigned int counter;

    /* current counter value */
    d = muldiv64(current_time - s->load_time, 
                 CUDA_TIMER_FREQ, ticks_per_sec);
    /* the timer goes down from latch to -1 (period of latch + 2) */
    if (d <= (s->counter_value + 1)) {
        counter = (s->counter_value - d) & 0xffff;
    } else {
        counter = (d - (s->counter_value + 1)) % (s->latch + 2);
        counter = (s->latch - counter) & 0xffff; 
    }
    
    /* Note: we consider the irq is raised on 0 */
    if (counter == 0xffff) {
        next_time = d + s->latch + 1;
    } else if (counter == 0) {
        next_time = d + s->latch + 2;
    } else {
        next_time = d + counter;
    }
#if 0
#ifdef DEBUG_CUDA
    printf("latch=%d counter=%" PRId64 " delta_next=%" PRId64 "\n", 
           s->latch, d, next_time - d);
#endif
#endif
    next_time = muldiv64(next_time, ticks_per_sec, CUDA_TIMER_FREQ) + 
        s->load_time;
    if (next_time <= current_time)
        next_time = current_time + 1;
    return next_time;
}

static void cuda_timer_update(CUDAState *s, CUDATimer *ti, 
                              int64_t current_time)
{
    if (!ti->timer)
        return;
    if ((s->acr & T1MODE) != T1MODE_CONT) {
        qemu_del_timer(ti->timer);
    } else {
        ti->next_irq_time = get_next_irq_time(ti, current_time);
        qemu_mod_timer(ti->timer, ti->next_irq_time);
    }
}

static void cuda_timer1(void *opaque)
{
    CUDAState *s = opaque;
    CUDATimer *ti = &s->timers[0];

    cuda_timer_update(s, ti, ti->next_irq_time);
    s->ifr |= T1_INT;
    cuda_update_irq(s);
}

static uint32_t cuda_readb(void *opaque, target_phys_addr_t addr)
{
    CUDAState *s = opaque;
    uint32_t val;

    addr = (addr >> 9) & 0xf;
    switch(addr) {
    case 0:
        val = s->b;
        break;
    case 1:
        val = s->a;
        break;
    case 2:
        val = s->dirb;
        break;
    case 3:
        val = s->dira;
        break;
    case 4:
        val = get_counter(&s->timers[0]) & 0xff;
        s->ifr &= ~T1_INT;
        cuda_update_irq(s);
        break;
    case 5:
        val = get_counter(&s->timers[0]) >> 8;
        cuda_update_irq(s);
        break;
    case 6:
        val = s->timers[0].latch & 0xff;
        break;
    case 7:
        /* XXX: check this */
        val = (s->timers[0].latch >> 8) & 0xff;
        break;
    case 8:
        val = get_counter(&s->timers[1]) & 0xff;
        s->ifr &= ~T2_INT;
        break;
    case 9:
        val = get_counter(&s->timers[1]) >> 8;
        break;
    case 10:
        val = s->sr;
        s->ifr &= ~SR_INT;
        cuda_update_irq(s);
        break;
    case 11:
        val = s->acr;
        break;
    case 12:
        val = s->pcr;
        break;
    case 13:
        val = s->ifr;
        if (s->ifr & s->ier) 
            val |= 0x80;
        break;
    case 14:
        val = s->ier | 0x80;
        break;
    default:
    case 15:
        val = s->anh;
        break;
    }
#ifdef DEBUG_CUDA
    if (addr != 13 || val != 0)
        printf("cuda: read: reg=0x%x val=%02x\n", addr, val);
#endif
    return val;
}

static void cuda_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)
{
    CUDAState *s = opaque;
    
    addr = (addr >> 9) & 0xf;
#ifdef DEBUG_CUDA
    printf("cuda: write: reg=0x%x val=%02x\n", addr, val);
#endif

    switch(addr) {
    case 0:
        s->b = val;
        cuda_update(s);
        break;
    case 1:
        s->a = val;
        break;
    case 2:
        s->dirb = val;
        break;
    case 3:
        s->dira = val;
        break;
    case 4:
        s->timers[0].latch = (s->timers[0].latch & 0xff00) | val;
        cuda_timer_update(s, &s->timers[0], qemu_get_clock(vm_clock));
        break;
    case 5:
        s->timers[0].latch = (s->timers[0].latch & 0xff) | (val << 8);
        s->ifr &= ~T1_INT;
        set_counter(s, &s->timers[0], s->timers[0].latch);
        break;
    case 6:
        s->timers[0].latch = (s->timers[0].latch & 0xff00) | val;
        cuda_timer_update(s, &s->timers[0], qemu_get_clock(vm_clock));
        break;
    case 7:
        s->timers[0].latch = (s->timers[0].latch & 0xff) | (val << 8);
        s->ifr &= ~T1_INT;
        cuda_timer_update(s, &s->timers[0], qemu_get_clock(vm_clock));
        break;
    case 8:
        s->timers[1].latch = val;
        set_counter(s, &s->timers[1], val);
        break;
    case 9:
        set_counter(s, &s->timers[1], (val << 8) | s->timers[1].latch);
        break;
    case 10:
        s->sr = val;
        break;
    case 11:
        s->acr = val;
        cuda_timer_update(s, &s->timers[0], qemu_get_clock(vm_clock));
        cuda_update(s);
        break;
    case 12:
        s->pcr = val;
        break;
    case 13:
        /* reset bits */
        s->ifr &= ~val;
        cuda_update_irq(s);
        break;
    case 14:
        if (val & IER_SET) {
            /* set bits */
            s->ier |= val & 0x7f;
        } else {
            /* reset bits */
            s->ier &= ~val;
        }
        cuda_update_irq(s);
        break;
    default:
    case 15:
        s->anh = val;
        break;
    }
}

/* NOTE: TIP and TREQ are negated */
static void cuda_update(CUDAState *s)
{
    int packet_received, len;

    packet_received = 0;
    if (!(s->b & TIP)) {
        /* transfer requested from host */

        if (s->acr & SR_OUT) {
            /* data output */
            if ((s->b & (TACK | TIP)) != (s->last_b & (TACK | TIP))) {
                if (s->data_out_index < sizeof(s->data_out)) {
#ifdef DEBUG_CUDA
                    printf("cuda: send: %02x\n", s->sr);
#endif
                    s->data_out[s->data_out_index++] = s->sr;
                    s->ifr |= SR_INT;
                    cuda_update_irq(s);
                }
            }
        } else {
            if (s->data_in_index < s->data_in_size) {
                /* data input */
                if ((s->b & (TACK | TIP)) != (s->last_b & (TACK | TIP))) {
                    s->sr = s->data_in[s->data_in_index++];
#ifdef DEBUG_CUDA
                    printf("cuda: recv: %02x\n", s->sr);
#endif
                    /* indicate end of transfer */
                    if (s->data_in_index >= s->data_in_size) {
                        s->b = (s->b | TREQ);
                    }
                    s->ifr |= SR_INT;
                    cuda_update_irq(s);
                }
            }
        }
    } else {
        /* no transfer requested: handle sync case */
        if ((s->last_b & TIP) && (s->b & TACK) != (s->last_b & TACK)) {
            /* update TREQ state each time TACK change state */
            if (s->b & TACK)
                s->b = (s->b | TREQ);
            else
                s->b = (s->b & ~TREQ);
            s->ifr |= SR_INT;
            cuda_update_irq(s);
        } else {
            if (!(s->last_b & TIP)) {
                /* handle end of host to cuda transfer */
                packet_received = (s->data_out_index > 0);
                /* always an IRQ at the end of transfer */
                s->ifr |= SR_INT;
                cuda_update_irq(s);
            }
            /* signal if there is data to read */
            if (s->data_in_index < s->data_in_size) {
                s->b = (s->b & ~TREQ);
            }
        }
    }

    s->last_acr = s->acr;
    s->last_b = s->b;

    /* NOTE: cuda_receive_packet_from_host() can call cuda_update()
       recursively */
    if (packet_received) {
        len = s->data_out_index;
        s->data_out_index = 0;
        cuda_receive_packet_from_host(s, s->data_out, len);
    }
}

static void cuda_send_packet_to_host(CUDAState *s, 
                                     const uint8_t *data, int len)
{
#ifdef DEBUG_CUDA_PACKET
    {
        int i;
        printf("cuda_send_packet_to_host:\n");
        for(i = 0; i < len; i++)
            printf(" %02x", data[i]);
        printf("\n");
    }
#endif
    memcpy(s->data_in, data, len);
    s->data_in_size = len;
    s->data_in_index = 0;
    cuda_update(s);
    s->ifr |= SR_INT;
    cuda_update_irq(s);
}

static void cuda_adb_poll(void *opaque)
{
    CUDAState *s = opaque;
    uint8_t obuf[ADB_MAX_OUT_LEN + 2];
    int olen;

    olen = adb_poll(&adb_bus, obuf + 2);
    if (olen > 0) {
        obuf[0] = ADB_PACKET;
        obuf[1] = 0x40; /* polled data */
        cuda_send_packet_to_host(s, obuf, olen + 2);
    }
    qemu_mod_timer(s->adb_poll_timer, 
                   qemu_get_clock(vm_clock) + 
                   (ticks_per_sec / CUDA_ADB_POLL_FREQ));
}

static void cuda_receive_packet(CUDAState *s, 
                                const uint8_t *data, int len)
{
    uint8_t obuf[16];
    int ti, autopoll;

    switch(data[0]) {
    case CUDA_AUTOPOLL:
        autopoll = (data[1] != 0);
        if (autopoll != s->autopoll) {
            s->autopoll = autopoll;
            if (autopoll) {
                qemu_mod_timer(s->adb_poll_timer, 
                               qemu_get_clock(vm_clock) + 
                               (ticks_per_sec / CUDA_ADB_POLL_FREQ));
            } else {
                qemu_del_timer(s->adb_poll_timer);
            }
        }
        obuf[0] = CUDA_PACKET;
        obuf[1] = data[1];
        cuda_send_packet_to_host(s, obuf, 2);
        break;
    case CUDA_GET_TIME:
    case CUDA_SET_TIME:
        /* XXX: add time support ? */
        ti = time(NULL) + RTC_OFFSET;
        obuf[0] = CUDA_PACKET;
        obuf[1] = 0;
        obuf[2] = 0;
        obuf[3] = ti >> 24;
        obuf[4] = ti >> 16;
        obuf[5] = ti >> 8;
        obuf[6] = ti;
        cuda_send_packet_to_host(s, obuf, 7);
        break;
    case CUDA_FILE_SERVER_FLAG:
    case CUDA_SET_DEVICE_LIST:
    case CUDA_SET_AUTO_RATE:
    case CUDA_SET_POWER_MESSAGES:
        obuf[0] = CUDA_PACKET;
        obuf[1] = 0;
        cuda_send_packet_to_host(s, obuf, 2);
        break;
    case CUDA_POWERDOWN:
        obuf[0] = CUDA_PACKET;
        obuf[1] = 0;
        cuda_send_packet_to_host(s, obuf, 2);
	qemu_system_shutdown_request();
	break;
    default:
        break;
    }
}

static void cuda_receive_packet_from_host(CUDAState *s, 
                                          const uint8_t *data, int len)
{
#ifdef DEBUG_CUDA_PACKET
    {
        int i;
        printf("cuda_receive_packet_from_host:\n");
        for(i = 0; i < len; i++)
            printf(" %02x", data[i]);
        printf("\n");
    }
#endif
    switch(data[0]) {
    case ADB_PACKET:
        {
            uint8_t obuf[ADB_MAX_OUT_LEN + 2];
            int olen;
            olen = adb_request(&adb_bus, obuf + 2, data + 1, len - 1);
            if (olen > 0) {
                obuf[0] = ADB_PACKET;
                obuf[1] = 0x00;
            } else {
                /* error */
                obuf[0] = ADB_PACKET;
                obuf[1] = -olen;
                olen = 0;
            }
            cuda_send_packet_to_host(s, obuf, olen + 2);
        }
        break;
    case CUDA_PACKET:
        cuda_receive_packet(s, data + 1, len - 1);
        break;
    }
}

static void cuda_writew (void *opaque, target_phys_addr_t addr, uint32_t value)
{
}

static void cuda_writel (void *opaque, target_phys_addr_t addr, uint32_t value)
{
}

static uint32_t cuda_readw (void *opaque, target_phys_addr_t addr)
{
    return 0;
}

static uint32_t cuda_readl (void *opaque, target_phys_addr_t addr)
{
    return 0;
}

static CPUWriteMemoryFunc *cuda_write[] = {
    &cuda_writeb,
    &cuda_writew,
    &cuda_writel,
};

static CPUReadMemoryFunc *cuda_read[] = {
    &cuda_readb,
    &cuda_readw,
    &cuda_readl,
};

int cuda_init(qemu_irq irq)
{
    CUDAState *s = &cuda_state;
    int cuda_mem_index;

    s->irq = irq;

    s->timers[0].index = 0;
    s->timers[0].timer = qemu_new_timer(vm_clock, cuda_timer1, s);
    s->timers[0].latch = 0xffff;
    set_counter(s, &s->timers[0], 0xffff);

    s->timers[1].index = 1;
    s->timers[1].latch = 0;
    //    s->ier = T1_INT | SR_INT;
    s->ier = 0;
    set_counter(s, &s->timers[1], 0xffff);

    s->adb_poll_timer = qemu_new_timer(vm_clock, cuda_adb_poll, s);
    cuda_mem_index = cpu_register_io_memory(0, cuda_read, cuda_write, s);
    return cuda_mem_index;
}