/**
 * @file sdrv_scr.c
 * @brief Semidrive Status and Controller Register driver
 *
 * @copyright Copyright (c) 2022  Semidrive Semiconductor.
 *            All rights reserved.
 */
#include <debug.h>
#include <bits.h>
#include <irq.h>
#include <reg.h>

#include "sdrv_scr.h"

#define SCR_REG_OFF_TYPE_RW 0x1000
#define SCR_REG_OFF_TYPE_RO 0x1100
#define SCR_REG_OFF_TYPE_L16 0x1200
#define SCR_REG_OFF_TYPE_L31 0x1400
#define SCR_REG_OFF_TYPE_R16W16 0x1600

#define BITFIELD_POS_MSK 0x1Fu

static inline uint32_t _scr_reg_off(uint32_t type)
{
    static const uint32_t reg_off[] = {
        [TYPE_RW] = SCR_REG_OFF_TYPE_RW,
        [TYPE_RO] = SCR_REG_OFF_TYPE_RO,
        [TYPE_L16] = SCR_REG_OFF_TYPE_L16,
        [TYPE_L31] = SCR_REG_OFF_TYPE_L31,
        [TYPE_R16W16] = SCR_REG_OFF_TYPE_R16W16,
    };

    if (type <= TYPE_R16W16)
        return reg_off[type];

    return 0;
}
static inline uint32_t _scr_reg(const uint32_t base, const scr_signal_t *signal)
{
    uint32_t reg_off =
        _scr_reg_off(signal->type) + (signal->start_bit >> 5) * 4;
    return base + reg_off;
}

static inline uint32_t _scr_read_reg(const uint32_t base,
                                     const scr_signal_t *signal)
{
    return readl(_scr_reg(base, signal));
}

static inline void _scr_write_reg(const uint32_t base,
                                  const scr_signal_t *signal, uint32_t val)
{
    writel(val, _scr_reg(base, signal));
}

uint32_t scr_get(const sdrv_scr_t *scr, const scr_signal_t *signal)
{
    ASSERT(scr != NULL && signal != NULL);

    uint32_t val = _scr_read_reg(scr->base, signal);
    uint32_t start_bit = signal->start_bit & BITFIELD_POS_MSK;

    return (val >> start_bit) & BIT_MASK(signal->width);
}

status_t scr_set(const sdrv_scr_t *scr, const scr_signal_t *signal,
                 uint32_t value)
{
    ASSERT(scr != NULL && signal != NULL);

    uint32_t start_bit;
    uint32_t val;
    irq_state_t state;

    start_bit = signal->start_bit & BITFIELD_POS_MSK;
    value &= BIT_MASK(signal->width);

    if (signal->type == TYPE_L16 || signal->type == TYPE_L31) {
        if (scr_is_locked(scr, signal))
            return SDRV_SCR_LOCKED;
    } else if (signal->type == TYPE_RO) {
        return SDRV_SCR_CANNOT_WRITE;
    } else if (signal->type == TYPE_R16W16) {
        if (start_bit >= 16)
            return SDRV_SCR_CANNOT_WRITE;
    }

    state = arch_irq_save();

    val = _scr_read_reg(scr->base, signal);
    val &= ~(BIT_MASK(signal->width) << start_bit);
    val |= value << start_bit;
    _scr_write_reg(scr->base, signal, val);

    arch_irq_restore(state);

    return SDRV_STATUS_OK;
}

status_t scr_lock(const sdrv_scr_t *scr, const scr_signal_t *signal)
{
    ASSERT(scr != NULL && signal != NULL);

    uint32_t start_bit;
    uint32_t val;
    irq_state_t state;
    status_t ret;

    if (scr_is_locked(scr, signal)) {
        return SDRV_SCR_LOCKED;
    }

    start_bit = signal->start_bit & BITFIELD_POS_MSK;
    ret = SDRV_SCR_CANNOT_LOCK;

    switch (signal->type) {
    case TYPE_L16:
        if (start_bit < 16) {
            state = arch_irq_save();

            val = _scr_read_reg(scr->base, signal);
            val |= BIT_MASK(signal->width) << (start_bit + 16);
            _scr_write_reg(scr->base, signal, val);

            arch_irq_restore(state);
            ret = SDRV_STATUS_OK;
        }
        break;

    case TYPE_L31:
        if (start_bit < 31) {
            state = arch_irq_save();

            val = _scr_read_reg(scr->base, signal);
            val |= 1ul << 31;
            _scr_write_reg(scr->base, signal, val);

            arch_irq_restore(state);
            ret = SDRV_STATUS_OK;
        }
        break;

    default:
        break;
    }

    return ret;
}

bool scr_is_locked(const sdrv_scr_t *scr, const scr_signal_t *signal)
{
    ASSERT(scr != NULL && signal != NULL);

    bool locked = false;

    uint32_t val = _scr_read_reg(scr->base, signal);
    uint16_t start_bit = signal->start_bit & BITFIELD_POS_MSK;

    switch (signal->type) {
    case TYPE_L16:
        if (start_bit < 16)
            locked = !!(val & (1ul << (start_bit + 16)));
        break;

    case TYPE_L31:
        if (start_bit < 31)
            locked = !!(val & (1ul << 31));
        break;

    default:
        break;
    }

    return locked;
}