/*
 * Aspeed ADC
 *
 * Copyright 2017-2021 IBM Corp.
 *
 * Andrew Jeffery <andrew@aj.id.au>
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/log.h"
#include "hw/irq.h"
#include "hw/qdev-properties.h"
#include "migration/vmstate.h"
#include "hw/adc/aspeed_adc.h"
#include "trace.h"

#define ASPEED_ADC_MEMORY_REGION_SIZE           0x1000
#define ASPEED_ADC_ENGINE_MEMORY_REGION_SIZE    0x100
#define  ASPEED_ADC_ENGINE_CH_EN_MASK           0xffff0000
#define   ASPEED_ADC_ENGINE_CH_EN(x)            ((BIT(x)) << 16)
#define  ASPEED_ADC_ENGINE_INIT                 BIT(8)
#define  ASPEED_ADC_ENGINE_AUTO_COMP            BIT(5)
#define  ASPEED_ADC_ENGINE_COMP                 BIT(4)
#define  ASPEED_ADC_ENGINE_MODE_MASK            0x0000000e
#define   ASPEED_ADC_ENGINE_MODE_OFF            (0b000 << 1)
#define   ASPEED_ADC_ENGINE_MODE_STANDBY        (0b001 << 1)
#define   ASPEED_ADC_ENGINE_MODE_NORMAL         (0b111 << 1)
#define  ASPEED_ADC_ENGINE_EN                   BIT(0)
#define ASPEED_ADC_HYST_EN                      BIT(31)

#define ASPEED_ADC_L_MASK       ((1 << 10) - 1)
#define ASPEED_ADC_L(x)         ((x) & ASPEED_ADC_L_MASK)
#define ASPEED_ADC_H(x)         (((x) >> 16) & ASPEED_ADC_L_MASK)
#define ASPEED_ADC_LH_MASK      (ASPEED_ADC_L_MASK << 16 | ASPEED_ADC_L_MASK)
#define LOWER_CHANNEL_MASK      ((1 << 10) - 1)
#define LOWER_CHANNEL_DATA(x)   ((x) & LOWER_CHANNEL_MASK)
#define UPPER_CHANNEL_DATA(x)   (((x) >> 16) & LOWER_CHANNEL_MASK)

#define TO_REG(addr) (addr >> 2)

#define ENGINE_CONTROL              TO_REG(0x00)
#define INTERRUPT_CONTROL           TO_REG(0x04)
#define VGA_DETECT_CONTROL          TO_REG(0x08)
#define CLOCK_CONTROL               TO_REG(0x0C)
#define DATA_CHANNEL_1_AND_0        TO_REG(0x10)
#define DATA_CHANNEL_7_AND_6        TO_REG(0x1C)
#define DATA_CHANNEL_9_AND_8        TO_REG(0x20)
#define DATA_CHANNEL_15_AND_14      TO_REG(0x2C)
#define BOUNDS_CHANNEL_0            TO_REG(0x30)
#define BOUNDS_CHANNEL_7            TO_REG(0x4C)
#define BOUNDS_CHANNEL_8            TO_REG(0x50)
#define BOUNDS_CHANNEL_15           TO_REG(0x6C)
#define HYSTERESIS_CHANNEL_0        TO_REG(0x70)
#define HYSTERESIS_CHANNEL_7        TO_REG(0x8C)
#define HYSTERESIS_CHANNEL_8        TO_REG(0x90)
#define HYSTERESIS_CHANNEL_15       TO_REG(0xAC)
#define INTERRUPT_SOURCE            TO_REG(0xC0)
#define COMPENSATING_AND_TRIMMING   TO_REG(0xC4)

static inline uint32_t update_channels(uint32_t current)
{
    return ((((current >> 16) & ASPEED_ADC_L_MASK) + 7) << 16) |
        ((current + 5) & ASPEED_ADC_L_MASK);
}

static bool breaks_threshold(AspeedADCEngineState *s, int reg)
{
    assert(reg >= DATA_CHANNEL_1_AND_0 &&
           reg < DATA_CHANNEL_1_AND_0 + s->nr_channels / 2);

    int a_bounds_reg = BOUNDS_CHANNEL_0 + (reg - DATA_CHANNEL_1_AND_0) * 2;
    int b_bounds_reg = a_bounds_reg + 1;
    uint32_t a_and_b = s->regs[reg];
    uint32_t a_bounds = s->regs[a_bounds_reg];
    uint32_t b_bounds = s->regs[b_bounds_reg];
    uint32_t a = ASPEED_ADC_L(a_and_b);
    uint32_t b = ASPEED_ADC_H(a_and_b);
    uint32_t a_lower = ASPEED_ADC_L(a_bounds);
    uint32_t a_upper = ASPEED_ADC_H(a_bounds);
    uint32_t b_lower = ASPEED_ADC_L(b_bounds);
    uint32_t b_upper = ASPEED_ADC_H(b_bounds);

    return (a < a_lower || a > a_upper) ||
           (b < b_lower || b > b_upper);
}

static uint32_t read_channel_sample(AspeedADCEngineState *s, int reg)
{
    assert(reg >= DATA_CHANNEL_1_AND_0 &&
           reg < DATA_CHANNEL_1_AND_0 + s->nr_channels / 2);

    /* Poor man's sampling */
    uint32_t value = s->regs[reg];
    s->regs[reg] = update_channels(s->regs[reg]);

    if (breaks_threshold(s, reg)) {
        s->regs[INTERRUPT_CONTROL] |= BIT(reg - DATA_CHANNEL_1_AND_0);
        qemu_irq_raise(s->irq);
    }

    return value;
}

static uint64_t aspeed_adc_engine_read(void *opaque, hwaddr addr,
                                       unsigned int size)
{
    AspeedADCEngineState *s = ASPEED_ADC_ENGINE(opaque);
    int reg = TO_REG(addr);
    uint32_t value = 0;

    switch (reg) {
    case BOUNDS_CHANNEL_8 ... BOUNDS_CHANNEL_15:
        if (s->nr_channels <= 8) {
            qemu_log_mask(LOG_GUEST_ERROR, "%s: engine[%u]: "
                          "bounds register %u invalid, only 0...7 valid\n",
                          __func__, s->engine_id, reg - BOUNDS_CHANNEL_0);
            break;
        }
        /* fallthrough */
    case HYSTERESIS_CHANNEL_8 ... HYSTERESIS_CHANNEL_15:
        if (s->nr_channels <= 8) {
            qemu_log_mask(LOG_GUEST_ERROR, "%s: engine[%u]: "
                          "hysteresis register %u invalid, only 0...7 valid\n",
                          __func__, s->engine_id, reg - HYSTERESIS_CHANNEL_0);
            break;
        }
        /* fallthrough */
    case BOUNDS_CHANNEL_0 ... BOUNDS_CHANNEL_7:
    case HYSTERESIS_CHANNEL_0 ... HYSTERESIS_CHANNEL_7:
    case ENGINE_CONTROL:
    case INTERRUPT_CONTROL:
    case VGA_DETECT_CONTROL:
    case CLOCK_CONTROL:
    case INTERRUPT_SOURCE:
    case COMPENSATING_AND_TRIMMING:
        value = s->regs[reg];
        break;
    case DATA_CHANNEL_9_AND_8 ... DATA_CHANNEL_15_AND_14:
        if (s->nr_channels <= 8) {
            qemu_log_mask(LOG_GUEST_ERROR, "%s: engine[%u]: "
                          "data register %u invalid, only 0...3 valid\n",
                          __func__, s->engine_id, reg - DATA_CHANNEL_1_AND_0);
            break;
        }
        /* fallthrough */
    case DATA_CHANNEL_1_AND_0 ... DATA_CHANNEL_7_AND_6:
        value = read_channel_sample(s, reg);
        /* Allow 16-bit reads of the data registers */
        if (addr & 0x2) {
            assert(size == 2);
            value >>= 16;
        }
        break;
    default:
        qemu_log_mask(LOG_UNIMP, "%s: engine[%u]: 0x%" HWADDR_PRIx "\n",
                      __func__, s->engine_id, addr);
        break;
    }

    trace_aspeed_adc_engine_read(s->engine_id, addr, value);
    return value;
}

static void aspeed_adc_engine_write(void *opaque, hwaddr addr, uint64_t value,
                                    unsigned int size)
{
    AspeedADCEngineState *s = ASPEED_ADC_ENGINE(opaque);
    int reg = TO_REG(addr);
    uint32_t init = 0;

    trace_aspeed_adc_engine_write(s->engine_id, addr, value);

    switch (reg) {
    case ENGINE_CONTROL:
        init = !!(value & ASPEED_ADC_ENGINE_EN);
        init *= ASPEED_ADC_ENGINE_INIT;

        value &= ~ASPEED_ADC_ENGINE_INIT;
        value |= init;

        value &= ~ASPEED_ADC_ENGINE_AUTO_COMP;
        break;
    case INTERRUPT_CONTROL:
    case VGA_DETECT_CONTROL:
    case CLOCK_CONTROL:
        break;
    case DATA_CHANNEL_9_AND_8 ... DATA_CHANNEL_15_AND_14:
        if (s->nr_channels <= 8) {
            qemu_log_mask(LOG_GUEST_ERROR, "%s: engine[%u]: "
                          "data register %u invalid, only 0...3 valid\n",
                          __func__, s->engine_id, reg - DATA_CHANNEL_1_AND_0);
            return;
        }
        /* fallthrough */
    case BOUNDS_CHANNEL_8 ... BOUNDS_CHANNEL_15:
        if (s->nr_channels <= 8) {
            qemu_log_mask(LOG_GUEST_ERROR, "%s: engine[%u]: "
                          "bounds register %u invalid, only 0...7 valid\n",
                          __func__, s->engine_id, reg - BOUNDS_CHANNEL_0);
            return;
        }
        /* fallthrough */
    case DATA_CHANNEL_1_AND_0 ... DATA_CHANNEL_7_AND_6:
    case BOUNDS_CHANNEL_0 ... BOUNDS_CHANNEL_7:
        value &= ASPEED_ADC_LH_MASK;
        break;
    case HYSTERESIS_CHANNEL_8 ... HYSTERESIS_CHANNEL_15:
        if (s->nr_channels <= 8) {
            qemu_log_mask(LOG_GUEST_ERROR, "%s: engine[%u]: "
                          "hysteresis register %u invalid, only 0...7 valid\n",
                          __func__, s->engine_id, reg - HYSTERESIS_CHANNEL_0);
            return;
        }
        /* fallthrough */
    case HYSTERESIS_CHANNEL_0 ... HYSTERESIS_CHANNEL_7:
        value &= (ASPEED_ADC_HYST_EN | ASPEED_ADC_LH_MASK);
        break;
    case INTERRUPT_SOURCE:
        value &= 0xffff;
        break;
    case COMPENSATING_AND_TRIMMING:
        value &= 0xf;
        break;
    default:
        qemu_log_mask(LOG_UNIMP, "%s: engine[%u]: "
                      "0x%" HWADDR_PRIx " 0x%" PRIx64 "\n",
                      __func__, s->engine_id, addr, value);
        break;
    }

    s->regs[reg] = value;
}

static const MemoryRegionOps aspeed_adc_engine_ops = {
    .read = aspeed_adc_engine_read,
    .write = aspeed_adc_engine_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .valid = {
        .min_access_size = 2,
        .max_access_size = 4,
        .unaligned = false,
    },
};

static const uint32_t aspeed_adc_resets[ASPEED_ADC_NR_REGS] = {
    [ENGINE_CONTROL]     = 0x00000000,
    [INTERRUPT_CONTROL]  = 0x00000000,
    [VGA_DETECT_CONTROL] = 0x0000000f,
    [CLOCK_CONTROL]      = 0x0000000f,
};

static void aspeed_adc_engine_reset(DeviceState *dev)
{
    AspeedADCEngineState *s = ASPEED_ADC_ENGINE(dev);

    memcpy(s->regs, aspeed_adc_resets, sizeof(aspeed_adc_resets));
}

static void aspeed_adc_engine_realize(DeviceState *dev, Error **errp)
{
    AspeedADCEngineState *s = ASPEED_ADC_ENGINE(dev);
    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
    g_autofree char *name = g_strdup_printf(TYPE_ASPEED_ADC_ENGINE ".%d",
                                            s->engine_id);

    assert(s->engine_id < 2);

    sysbus_init_irq(sbd, &s->irq);

    memory_region_init_io(&s->mmio, OBJECT(s), &aspeed_adc_engine_ops, s, name,
                          ASPEED_ADC_ENGINE_MEMORY_REGION_SIZE);

    sysbus_init_mmio(sbd, &s->mmio);
}

static const VMStateDescription vmstate_aspeed_adc_engine = {
    .name = TYPE_ASPEED_ADC,
    .version_id = 1,
    .minimum_version_id = 1,
    .fields = (VMStateField[]) {
        VMSTATE_UINT32_ARRAY(regs, AspeedADCEngineState, ASPEED_ADC_NR_REGS),
        VMSTATE_END_OF_LIST(),
    }
};

static Property aspeed_adc_engine_properties[] = {
    DEFINE_PROP_UINT32("engine-id", AspeedADCEngineState, engine_id, 0),
    DEFINE_PROP_UINT32("nr-channels", AspeedADCEngineState, nr_channels, 0),
    DEFINE_PROP_END_OF_LIST(),
};

static void aspeed_adc_engine_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);

    dc->realize = aspeed_adc_engine_realize;
    dc->reset = aspeed_adc_engine_reset;
    device_class_set_props(dc, aspeed_adc_engine_properties);
    dc->desc = "Aspeed Analog-to-Digital Engine";
    dc->vmsd = &vmstate_aspeed_adc_engine;
}

static const TypeInfo aspeed_adc_engine_info = {
    .name = TYPE_ASPEED_ADC_ENGINE,
    .parent = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(AspeedADCEngineState),
    .class_init = aspeed_adc_engine_class_init,
};

static void aspeed_adc_instance_init(Object *obj)
{
    AspeedADCState *s = ASPEED_ADC(obj);
    AspeedADCClass *aac = ASPEED_ADC_GET_CLASS(obj);
    uint32_t nr_channels = ASPEED_ADC_NR_CHANNELS / aac->nr_engines;

    for (int i = 0; i < aac->nr_engines; i++) {
        AspeedADCEngineState *engine = &s->engines[i];
        object_initialize_child(obj, "engine[*]", engine,
                                TYPE_ASPEED_ADC_ENGINE);
        qdev_prop_set_uint32(DEVICE(engine), "engine-id", i);
        qdev_prop_set_uint32(DEVICE(engine), "nr-channels", nr_channels);
    }
}

static void aspeed_adc_set_irq(void *opaque, int n, int level)
{
    AspeedADCState *s = opaque;
    AspeedADCClass *aac = ASPEED_ADC_GET_CLASS(s);
    uint32_t pending = 0;

    /* TODO: update Global IRQ status register on AST2600 (Need specs) */
    for (int i = 0; i < aac->nr_engines; i++) {
        uint32_t irq_status = s->engines[i].regs[INTERRUPT_CONTROL] & 0xFF;
        pending |= irq_status << (i * 8);
    }

    qemu_set_irq(s->irq, !!pending);
}

static void aspeed_adc_realize(DeviceState *dev, Error **errp)
{
    AspeedADCState *s = ASPEED_ADC(dev);
    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
    AspeedADCClass *aac = ASPEED_ADC_GET_CLASS(dev);

    qdev_init_gpio_in_named_with_opaque(DEVICE(sbd), aspeed_adc_set_irq,
                                        s, NULL, aac->nr_engines);

    sysbus_init_irq(sbd, &s->irq);

    memory_region_init(&s->mmio, OBJECT(s), TYPE_ASPEED_ADC,
                       ASPEED_ADC_MEMORY_REGION_SIZE);

    sysbus_init_mmio(sbd, &s->mmio);

    for (int i = 0; i < aac->nr_engines; i++) {
        Object *eng = OBJECT(&s->engines[i]);

        if (!sysbus_realize(SYS_BUS_DEVICE(eng), errp)) {
            return;
        }
        sysbus_connect_irq(SYS_BUS_DEVICE(eng), 0,
                           qdev_get_gpio_in(DEVICE(sbd), i));
        memory_region_add_subregion(&s->mmio,
                                    i * ASPEED_ADC_ENGINE_MEMORY_REGION_SIZE,
                                    &s->engines[i].mmio);
    }
}

static void aspeed_adc_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    AspeedADCClass *aac = ASPEED_ADC_CLASS(klass);

    dc->realize = aspeed_adc_realize;
    dc->desc = "Aspeed Analog-to-Digital Converter";
    aac->nr_engines = 1;
}

static void aspeed_2600_adc_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    AspeedADCClass *aac = ASPEED_ADC_CLASS(klass);

    dc->desc = "ASPEED 2600 ADC Controller";
    aac->nr_engines = 2;
}

static const TypeInfo aspeed_adc_info = {
    .name = TYPE_ASPEED_ADC,
    .parent = TYPE_SYS_BUS_DEVICE,
    .instance_init = aspeed_adc_instance_init,
    .instance_size = sizeof(AspeedADCState),
    .class_init = aspeed_adc_class_init,
    .class_size = sizeof(AspeedADCClass),
    .abstract   = true,
};

static const TypeInfo aspeed_2400_adc_info = {
    .name = TYPE_ASPEED_2400_ADC,
    .parent = TYPE_ASPEED_ADC,
};

static const TypeInfo aspeed_2500_adc_info = {
    .name = TYPE_ASPEED_2500_ADC,
    .parent = TYPE_ASPEED_ADC,
};

static const TypeInfo aspeed_2600_adc_info = {
    .name = TYPE_ASPEED_2600_ADC,
    .parent = TYPE_ASPEED_ADC,
    .class_init = aspeed_2600_adc_class_init,
};

static void aspeed_adc_register_types(void)
{
    type_register_static(&aspeed_adc_engine_info);
    type_register_static(&aspeed_adc_info);
    type_register_static(&aspeed_2400_adc_info);
    type_register_static(&aspeed_2500_adc_info);
    type_register_static(&aspeed_2600_adc_info);
}

type_init(aspeed_adc_register_types);
