/*
 * dim2_hal.c - DIM2 HAL implementation
 * (MediaLB, Device Interface Macro IP, OS62420)
 *
 * Copyright (C) 2015-2016, Microchip Technology Germany II GmbH & Co. KG
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * This file is licensed under GPLv2.
 */

/* Author: Andrey Shvetsov <andrey.shvetsov@k2l.de> */

#include "dim2_hal.h"
#include "dim2_errors.h"
#include "dim2_reg.h"
#include <linux/stddef.h>
#include <linux/kernel.h>

/*
 * Size factor for isochronous DBR buffer.
 * Minimal value is 3.
 */
#define ISOC_DBR_FACTOR 3u

/*
 * Number of 32-bit units for DBR map.
 *
 * 1: block size is 512, max allocation is 16K
 * 2: block size is 256, max allocation is 8K
 * 4: block size is 128, max allocation is 4K
 * 8: block size is 64, max allocation is 2K
 *
 * Min allocated space is block size.
 * Max possible allocated space is 32 blocks.
 */
#define DBR_MAP_SIZE 2

/* -------------------------------------------------------------------------- */
/* not configurable area */

#define CDT 0x00
#define ADT 0x40
#define MLB_CAT 0x80
#define AHB_CAT 0x88

#define DBR_SIZE  (16 * 1024) /* specified by IP */
#define DBR_BLOCK_SIZE  (DBR_SIZE / 32 / DBR_MAP_SIZE)

#define ROUND_UP_TO(x, d)  (DIV_ROUND_UP(x, (d)) * (d))

/* -------------------------------------------------------------------------- */
/* generic helper functions and macros */

static inline u32 bit_mask(u8 position)
{
        return (u32)1 << position;
}

static inline bool dim_on_error(u8 error_id, const char *error_message)
{
        dimcb_on_error(error_id, error_message);
        return false;
}

/* -------------------------------------------------------------------------- */
/* types and local variables */

struct async_tx_dbr {
        u8 ch_addr;
        u16 rpc;
        u16 wpc;
        u16 rest_size;
        u16 sz_queue[CDT0_RPC_MASK + 1];
};

struct lld_global_vars_t {
        bool dim_is_initialized;
        bool mcm_is_initialized;
        struct dim2_regs __iomem *dim2; /* DIM2 core base address */
        struct async_tx_dbr atx_dbr;
        u32 fcnt;
        u32 dbr_map[DBR_MAP_SIZE];
};

static struct lld_global_vars_t g = { false };

/* -------------------------------------------------------------------------- */

static int dbr_get_mask_size(u16 size)
{
        int i;

        for (i = 0; i < 6; i++)
                if (size <= (DBR_BLOCK_SIZE << i))
                        return 1 << i;
        return 0;
}

/**
 * Allocates DBR memory.
 * @param size Allocating memory size.
 * @return Offset in DBR memory by success or DBR_SIZE if out of memory.
 */
static int alloc_dbr(u16 size)
{
        int mask_size;
        int i, block_idx = 0;

        if (size <= 0)
                return DBR_SIZE; /* out of memory */

        mask_size = dbr_get_mask_size(size);
        if (mask_size == 0)
                return DBR_SIZE; /* out of memory */

        for (i = 0; i < DBR_MAP_SIZE; i++) {
                u32 const blocks = DIV_ROUND_UP(size, DBR_BLOCK_SIZE);
                u32 mask = ~((~(u32)0) << blocks);

                do {
                        if ((g.dbr_map[i] & mask) == 0) {
                                g.dbr_map[i] |= mask;
                                return block_idx * DBR_BLOCK_SIZE;
                        }
                        block_idx += mask_size;
                        /* do shift left with 2 steps in case mask_size == 32 */
                        mask <<= mask_size - 1;
                } while ((mask <<= 1) != 0);
        }

        return DBR_SIZE; /* out of memory */
}

static void free_dbr(int offs, int size)
{
        int block_idx = offs / DBR_BLOCK_SIZE;
        u32 const blocks = DIV_ROUND_UP(size, DBR_BLOCK_SIZE);
        u32 mask = ~((~(u32)0) << blocks);

        mask <<= block_idx % 32;
        g.dbr_map[block_idx / 32] &= ~mask;
}

/* -------------------------------------------------------------------------- */

static void dim2_transfer_madr(u32 val)
{
        dimcb_io_write(&g.dim2->MADR, val);

        /* wait for transfer completion */
        while ((dimcb_io_read(&g.dim2->MCTL) & 1) != 1)
                continue;

        dimcb_io_write(&g.dim2->MCTL, 0);   /* clear transfer complete */
}

static void dim2_clear_dbr(u16 addr, u16 size)
{
        enum { MADR_TB_BIT = 30, MADR_WNR_BIT = 31 };

        u16 const end_addr = addr + size;
        u32 const cmd = bit_mask(MADR_WNR_BIT) | bit_mask(MADR_TB_BIT);

        dimcb_io_write(&g.dim2->MCTL, 0);   /* clear transfer complete */
        dimcb_io_write(&g.dim2->MDAT0, 0);

        for (; addr < end_addr; addr++)
                dim2_transfer_madr(cmd | addr);
}

static u32 dim2_read_ctr(u32 ctr_addr, u16 mdat_idx)
{
        dim2_transfer_madr(ctr_addr);

        return dimcb_io_read((&g.dim2->MDAT0) + mdat_idx);
}

static void dim2_write_ctr_mask(u32 ctr_addr, const u32 *mask, const u32 *value)
{
        enum { MADR_WNR_BIT = 31 };

        dimcb_io_write(&g.dim2->MCTL, 0);   /* clear transfer complete */

        if (mask[0] != 0)
                dimcb_io_write(&g.dim2->MDAT0, value[0]);
        if (mask[1] != 0)
                dimcb_io_write(&g.dim2->MDAT1, value[1]);
        if (mask[2] != 0)
                dimcb_io_write(&g.dim2->MDAT2, value[2]);
        if (mask[3] != 0)
                dimcb_io_write(&g.dim2->MDAT3, value[3]);

        dimcb_io_write(&g.dim2->MDWE0, mask[0]);
        dimcb_io_write(&g.dim2->MDWE1, mask[1]);
        dimcb_io_write(&g.dim2->MDWE2, mask[2]);
        dimcb_io_write(&g.dim2->MDWE3, mask[3]);

        dim2_transfer_madr(bit_mask(MADR_WNR_BIT) | ctr_addr);
}

static inline void dim2_write_ctr(u32 ctr_addr, const u32 *value)
{
        u32 const mask[4] = { 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };

        dim2_write_ctr_mask(ctr_addr, mask, value);
}

static inline void dim2_clear_ctr(u32 ctr_addr)
{
        u32 const value[4] = { 0, 0, 0, 0 };

        dim2_write_ctr(ctr_addr, value);
}

static void dim2_configure_cat(u8 cat_base, u8 ch_addr, u8 ch_type,
                               bool read_not_write)
{
        bool isoc_fce = ch_type == CAT_CT_VAL_ISOC;
        bool sync_mfe = ch_type == CAT_CT_VAL_SYNC;
        u16 const cat =
                (read_not_write << CAT_RNW_BIT) |
                (ch_type << CAT_CT_SHIFT) |
                (ch_addr << CAT_CL_SHIFT) |
                (isoc_fce << CAT_FCE_BIT) |
                (sync_mfe << CAT_MFE_BIT) |
                (false << CAT_MT_BIT) |
                (true << CAT_CE_BIT);
        u8 const ctr_addr = cat_base + ch_addr / 8;
        u8 const idx = (ch_addr % 8) / 2;
        u8 const shift = (ch_addr % 2) * 16;
        u32 mask[4] = { 0, 0, 0, 0 };
        u32 value[4] = { 0, 0, 0, 0 };

        mask[idx] = (u32)0xFFFF << shift;
        value[idx] = cat << shift;
        dim2_write_ctr_mask(ctr_addr, mask, value);
}

static void dim2_clear_cat(u8 cat_base, u8 ch_addr)
{
        u8 const ctr_addr = cat_base + ch_addr / 8;
        u8 const idx = (ch_addr % 8) / 2;
        u8 const shift = (ch_addr % 2) * 16;
        u32 mask[4] = { 0, 0, 0, 0 };
        u32 value[4] = { 0, 0, 0, 0 };

        mask[idx] = (u32)0xFFFF << shift;
        dim2_write_ctr_mask(ctr_addr, mask, value);
}

static void dim2_configure_cdt(u8 ch_addr, u16 dbr_address, u16 hw_buffer_size,
                               u16 packet_length)
{
        u32 cdt[4] = { 0, 0, 0, 0 };

        if (packet_length)
                cdt[1] = ((packet_length - 1) << CDT1_BS_ISOC_SHIFT);

        cdt[3] =
                ((hw_buffer_size - 1) << CDT3_BD_SHIFT) |
                (dbr_address << CDT3_BA_SHIFT);
        dim2_write_ctr(CDT + ch_addr, cdt);
}

static u16 dim2_rpc(u8 ch_addr)
{
        u32 cdt0 = dim2_read_ctr(CDT + ch_addr, 0);

        return (cdt0 >> CDT0_RPC_SHIFT) & CDT0_RPC_MASK;
}

static void dim2_clear_cdt(u8 ch_addr)
{
        u32 cdt[4] = { 0, 0, 0, 0 };

        dim2_write_ctr(CDT + ch_addr, cdt);
}

static void dim2_configure_adt(u8 ch_addr)
{
        u32 adt[4] = { 0, 0, 0, 0 };

        adt[0] =
                (true << ADT0_CE_BIT) |
                (true << ADT0_LE_BIT) |
                (0 << ADT0_PG_BIT);

        dim2_write_ctr(ADT + ch_addr, adt);
}

static void dim2_clear_adt(u8 ch_addr)
{
        u32 adt[4] = { 0, 0, 0, 0 };

        dim2_write_ctr(ADT + ch_addr, adt);
}

static void dim2_start_ctrl_async(u8 ch_addr, u8 idx, u32 buf_addr,
                                  u16 buffer_size)
{
        u8 const shift = idx * 16;

        u32 mask[4] = { 0, 0, 0, 0 };
        u32 adt[4] = { 0, 0, 0, 0 };

        mask[1] =
                bit_mask(ADT1_PS_BIT + shift) |
                bit_mask(ADT1_RDY_BIT + shift) |
                (ADT1_CTRL_ASYNC_BD_MASK << (ADT1_BD_SHIFT + shift));
        adt[1] =
                (true << (ADT1_PS_BIT + shift)) |
                (true << (ADT1_RDY_BIT + shift)) |
                ((buffer_size - 1) << (ADT1_BD_SHIFT + shift));

        mask[idx + 2] = 0xFFFFFFFF;
        adt[idx + 2] = buf_addr;

        dim2_write_ctr_mask(ADT + ch_addr, mask, adt);
}

static void dim2_start_isoc_sync(u8 ch_addr, u8 idx, u32 buf_addr,
                                 u16 buffer_size)
{
        u8 const shift = idx * 16;

        u32 mask[4] = { 0, 0, 0, 0 };
        u32 adt[4] = { 0, 0, 0, 0 };

        mask[1] =
                bit_mask(ADT1_RDY_BIT + shift) |
                (ADT1_ISOC_SYNC_BD_MASK << (ADT1_BD_SHIFT + shift));
        adt[1] =
                (true << (ADT1_RDY_BIT + shift)) |
                ((buffer_size - 1) << (ADT1_BD_SHIFT + shift));

        mask[idx + 2] = 0xFFFFFFFF;
        adt[idx + 2] = buf_addr;

        dim2_write_ctr_mask(ADT + ch_addr, mask, adt);
}

static void dim2_clear_ctram(void)
{
        u32 ctr_addr;

        for (ctr_addr = 0; ctr_addr < 0x90; ctr_addr++)
                dim2_clear_ctr(ctr_addr);
}

static void dim2_configure_channel(
        u8 ch_addr, u8 type, u8 is_tx, u16 dbr_address, u16 hw_buffer_size,
        u16 packet_length)
{
        dim2_configure_cdt(ch_addr, dbr_address, hw_buffer_size, packet_length);
        dim2_configure_cat(MLB_CAT, ch_addr, type, is_tx ? 1 : 0);

        dim2_configure_adt(ch_addr);
        dim2_configure_cat(AHB_CAT, ch_addr, type, is_tx ? 0 : 1);

        /* unmask interrupt for used channel, enable mlb_sys_int[0] interrupt */
        dimcb_io_write(&g.dim2->ACMR0,
                       dimcb_io_read(&g.dim2->ACMR0) | bit_mask(ch_addr));
}

static void dim2_clear_channel(u8 ch_addr)
{
        /* mask interrupt for used channel, disable mlb_sys_int[0] interrupt */
        dimcb_io_write(&g.dim2->ACMR0,
                       dimcb_io_read(&g.dim2->ACMR0) & ~bit_mask(ch_addr));

        dim2_clear_cat(AHB_CAT, ch_addr);
        dim2_clear_adt(ch_addr);

        dim2_clear_cat(MLB_CAT, ch_addr);
        dim2_clear_cdt(ch_addr);

        /* clear channel status bit */
        dimcb_io_write(&g.dim2->ACSR0, bit_mask(ch_addr));
}

/* -------------------------------------------------------------------------- */
/* trace async tx dbr fill state */

static inline u16 norm_pc(u16 pc)
{
        return pc & CDT0_RPC_MASK;
}

static void dbrcnt_init(u8 ch_addr, u16 dbr_size)
{
        g.atx_dbr.rest_size = dbr_size;
        g.atx_dbr.rpc = dim2_rpc(ch_addr);
        g.atx_dbr.wpc = g.atx_dbr.rpc;
}

static void dbrcnt_enq(int buf_sz)
{
        g.atx_dbr.rest_size -= buf_sz;
        g.atx_dbr.sz_queue[norm_pc(g.atx_dbr.wpc)] = buf_sz;
        g.atx_dbr.wpc++;
}

u16 dim_dbr_space(struct dim_channel *ch)
{
        u16 cur_rpc;
        struct async_tx_dbr *dbr = &g.atx_dbr;

        if (ch->addr != dbr->ch_addr)
                return 0xFFFF;

        cur_rpc = dim2_rpc(ch->addr);

        while (norm_pc(dbr->rpc) != cur_rpc) {
                dbr->rest_size += dbr->sz_queue[norm_pc(dbr->rpc)];
                dbr->rpc++;
        }

        if ((u16)(dbr->wpc - dbr->rpc) >= CDT0_RPC_MASK)
                return 0;

        return dbr->rest_size;
}

/* -------------------------------------------------------------------------- */
/* channel state helpers */

static void state_init(struct int_ch_state *state)
{
        state->request_counter = 0;
        state->service_counter = 0;

        state->idx1 = 0;
        state->idx2 = 0;
        state->level = 0;
}

/* -------------------------------------------------------------------------- */
/* macro helper functions */

static inline bool check_channel_address(u32 ch_address)
{
        return ch_address > 0 && (ch_address % 2) == 0 &&
               (ch_address / 2) <= (u32)CAT_CL_MASK;
}

static inline bool check_packet_length(u32 packet_length)
{
        u16 const max_size = ((u16)CDT3_BD_ISOC_MASK + 1u) / ISOC_DBR_FACTOR;

        if (packet_length <= 0)
                return false; /* too small */

        if (packet_length > max_size)
                return false; /* too big */

        if (packet_length - 1u > (u32)CDT1_BS_ISOC_MASK)
                return false; /* too big */

        return true;
}

static inline bool check_bytes_per_frame(u32 bytes_per_frame)
{
        u16 const bd_factor = g.fcnt + 2;
        u16 const max_size = ((u16)CDT3_BD_MASK + 1u) >> bd_factor;

        if (bytes_per_frame <= 0)
                return false; /* too small */

        if (bytes_per_frame > max_size)
                return false; /* too big */

        return true;
}

static inline u16 norm_ctrl_async_buffer_size(u16 buf_size)
{
        u16 const max_size = (u16)ADT1_CTRL_ASYNC_BD_MASK + 1u;

        if (buf_size > max_size)
                return max_size;

        return buf_size;
}

static inline u16 norm_isoc_buffer_size(u16 buf_size, u16 packet_length)
{
        u16 n;
        u16 const max_size = (u16)ADT1_ISOC_SYNC_BD_MASK + 1u;

        if (buf_size > max_size)
                buf_size = max_size;

        n = buf_size / packet_length;

        if (n < 2u)
                return 0; /* too small buffer for given packet_length */

        return packet_length * n;
}

static inline u16 norm_sync_buffer_size(u16 buf_size, u16 bytes_per_frame)
{
        u16 n;
        u16 const max_size = (u16)ADT1_ISOC_SYNC_BD_MASK + 1u;
        u32 const unit = bytes_per_frame << g.fcnt;

        if (buf_size > max_size)
                buf_size = max_size;

        n = buf_size / unit;

        if (n < 1u)
                return 0; /* too small buffer for given bytes_per_frame */

        return unit * n;
}

static void dim2_cleanup(void)
{
        /* disable MediaLB */
        dimcb_io_write(&g.dim2->MLBC0, false << MLBC0_MLBEN_BIT);

        dim2_clear_ctram();

        /* disable mlb_int interrupt */
        dimcb_io_write(&g.dim2->MIEN, 0);

        /* clear status for all dma channels */
        dimcb_io_write(&g.dim2->ACSR0, 0xFFFFFFFF);
        dimcb_io_write(&g.dim2->ACSR1, 0xFFFFFFFF);

        /* mask interrupts for all channels */
        dimcb_io_write(&g.dim2->ACMR0, 0);
        dimcb_io_write(&g.dim2->ACMR1, 0);
}

static void dim2_initialize(bool enable_6pin, u8 mlb_clock)
{
        dim2_cleanup();

        /* configure and enable MediaLB */
        dimcb_io_write(&g.dim2->MLBC0,
                       enable_6pin << MLBC0_MLBPEN_BIT |
                       mlb_clock << MLBC0_MLBCLK_SHIFT |
                       g.fcnt << MLBC0_FCNT_SHIFT |
                       true << MLBC0_MLBEN_BIT);

        /* activate all HBI channels */
        dimcb_io_write(&g.dim2->HCMR0, 0xFFFFFFFF);
        dimcb_io_write(&g.dim2->HCMR1, 0xFFFFFFFF);

        /* enable HBI */
        dimcb_io_write(&g.dim2->HCTL, bit_mask(HCTL_EN_BIT));

        /* configure DMA */
        dimcb_io_write(&g.dim2->ACTL,
                       ACTL_DMA_MODE_VAL_DMA_MODE_1 << ACTL_DMA_MODE_BIT |
                       true << ACTL_SCE_BIT);
}

static bool dim2_is_mlb_locked(void)
{
        u32 const mask0 = bit_mask(MLBC0_MLBLK_BIT);
        u32 const mask1 = bit_mask(MLBC1_CLKMERR_BIT) |
                          bit_mask(MLBC1_LOCKERR_BIT);
        u32 const c1 = dimcb_io_read(&g.dim2->MLBC1);
        u32 const nda_mask = (u32)MLBC1_NDA_MASK << MLBC1_NDA_SHIFT;

        dimcb_io_write(&g.dim2->MLBC1, c1 & nda_mask);
        return (dimcb_io_read(&g.dim2->MLBC1) & mask1) == 0 &&
               (dimcb_io_read(&g.dim2->MLBC0) & mask0) != 0;
}

/* -------------------------------------------------------------------------- */
/* channel help routines */

static inline bool service_channel(u8 ch_addr, u8 idx)
{
        u8 const shift = idx * 16;
        u32 const adt1 = dim2_read_ctr(ADT + ch_addr, 1);
        u32 mask[4] = { 0, 0, 0, 0 };
        u32 adt_w[4] = { 0, 0, 0, 0 };

        if (((adt1 >> (ADT1_DNE_BIT + shift)) & 1) == 0)
                return false;

        mask[1] =
                bit_mask(ADT1_DNE_BIT + shift) |
                bit_mask(ADT1_ERR_BIT + shift) |
                bit_mask(ADT1_RDY_BIT + shift);
        dim2_write_ctr_mask(ADT + ch_addr, mask, adt_w);

        /* clear channel status bit */
        dimcb_io_write(&g.dim2->ACSR0, bit_mask(ch_addr));

        return true;
}

/* -------------------------------------------------------------------------- */
/* channel init routines */

static void isoc_init(struct dim_channel *ch, u8 ch_addr, u16 packet_length)
{
        state_init(&ch->state);

        ch->addr = ch_addr;

        ch->packet_length = packet_length;
        ch->bytes_per_frame = 0;
        ch->done_sw_buffers_number = 0;
}

static void sync_init(struct dim_channel *ch, u8 ch_addr, u16 bytes_per_frame)
{
        state_init(&ch->state);

        ch->addr = ch_addr;

        ch->packet_length = 0;
        ch->bytes_per_frame = bytes_per_frame;
        ch->done_sw_buffers_number = 0;
}

static void channel_init(struct dim_channel *ch, u8 ch_addr)
{
        state_init(&ch->state);

        ch->addr = ch_addr;

        ch->packet_length = 0;
        ch->bytes_per_frame = 0;
        ch->done_sw_buffers_number = 0;
}

/* returns true if channel interrupt state is cleared */
static bool channel_service_interrupt(struct dim_channel *ch)
{
        struct int_ch_state *const state = &ch->state;

        if (!service_channel(ch->addr, state->idx2))
                return false;

        state->idx2 ^= 1;
        state->request_counter++;
        return true;
}

static bool channel_start(struct dim_channel *ch, u32 buf_addr, u16 buf_size)
{
        struct int_ch_state *const state = &ch->state;

        if (buf_size <= 0)
                return dim_on_error(DIM_ERR_BAD_BUFFER_SIZE, "Bad buffer size");

        if (ch->packet_length == 0 && ch->bytes_per_frame == 0 &&
            buf_size != norm_ctrl_async_buffer_size(buf_size))
                return dim_on_error(DIM_ERR_BAD_BUFFER_SIZE,
                                    "Bad control/async buffer size");

        if (ch->packet_length &&
            buf_size != norm_isoc_buffer_size(buf_size, ch->packet_length))
                return dim_on_error(DIM_ERR_BAD_BUFFER_SIZE,
                                    "Bad isochronous buffer size");

        if (ch->bytes_per_frame &&
            buf_size != norm_sync_buffer_size(buf_size, ch->bytes_per_frame))
                return dim_on_error(DIM_ERR_BAD_BUFFER_SIZE,
                                    "Bad synchronous buffer size");

        if (state->level >= 2u)
                return dim_on_error(DIM_ERR_OVERFLOW, "Channel overflow");

        ++state->level;

        if (ch->addr == g.atx_dbr.ch_addr)
                dbrcnt_enq(buf_size);

        if (ch->packet_length || ch->bytes_per_frame)
                dim2_start_isoc_sync(ch->addr, state->idx1, buf_addr, buf_size);
        else
                dim2_start_ctrl_async(ch->addr, state->idx1, buf_addr,
                                      buf_size);
        state->idx1 ^= 1;

        return true;
}

static u8 channel_service(struct dim_channel *ch)
{
        struct int_ch_state *const state = &ch->state;

        if (state->service_counter != state->request_counter) {
                state->service_counter++;
                if (state->level == 0)
                        return DIM_ERR_UNDERFLOW;

                --state->level;
                ch->done_sw_buffers_number++;
        }

        return DIM_NO_ERROR;
}

static bool channel_detach_buffers(struct dim_channel *ch, u16 buffers_number)
{
        if (buffers_number > ch->done_sw_buffers_number)
                return dim_on_error(DIM_ERR_UNDERFLOW, "Channel underflow");

        ch->done_sw_buffers_number -= buffers_number;
        return true;
}

/* -------------------------------------------------------------------------- */
/* API */

u8 dim_startup(struct dim2_regs __iomem *dim_base_address, u32 mlb_clock,
               u32 fcnt)
{
        g.dim_is_initialized = false;

        if (!dim_base_address)
                return DIM_INIT_ERR_DIM_ADDR;

        /* MediaLB clock: 0 - 256 fs, 1 - 512 fs, 2 - 1024 fs, 3 - 2048 fs */
        /* MediaLB clock: 4 - 3072 fs, 5 - 4096 fs, 6 - 6144 fs, 7 - 8192 fs */
        if (mlb_clock >= 8)
                return DIM_INIT_ERR_MLB_CLOCK;

        if (fcnt > MLBC0_FCNT_MAX_VAL)
                return DIM_INIT_ERR_MLB_CLOCK;

        g.dim2 = dim_base_address;
        g.fcnt = fcnt;
        g.dbr_map[0] = 0;
        g.dbr_map[1] = 0;

        dim2_initialize(mlb_clock >= 3, mlb_clock);

        g.dim_is_initialized = true;

        return DIM_NO_ERROR;
}

void dim_shutdown(void)
{
        g.dim_is_initialized = false;
        dim2_cleanup();
}

bool dim_get_lock_state(void)
{
        return dim2_is_mlb_locked();
}

static u8 init_ctrl_async(struct dim_channel *ch, u8 type, u8 is_tx,
                          u16 ch_address, u16 hw_buffer_size)
{
        if (!g.dim_is_initialized || !ch)
                return DIM_ERR_DRIVER_NOT_INITIALIZED;

        if (!check_channel_address(ch_address))
                return DIM_INIT_ERR_CHANNEL_ADDRESS;

        ch->dbr_size = ROUND_UP_TO(hw_buffer_size, DBR_BLOCK_SIZE);
        ch->dbr_addr = alloc_dbr(ch->dbr_size);
        if (ch->dbr_addr >= DBR_SIZE)
                return DIM_INIT_ERR_OUT_OF_MEMORY;

        channel_init(ch, ch_address / 2);

        dim2_configure_channel(ch->addr, type, is_tx,
                               ch->dbr_addr, ch->dbr_size, 0);

        return DIM_NO_ERROR;
}

void dim_service_mlb_int_irq(void)
{
        dimcb_io_write(&g.dim2->MS0, 0);
        dimcb_io_write(&g.dim2->MS1, 0);
}

u16 dim_norm_ctrl_async_buffer_size(u16 buf_size)
{
        return norm_ctrl_async_buffer_size(buf_size);
}

/**
 * Retrieves maximal possible correct buffer size for isochronous data type
 * conform to given packet length and not bigger than given buffer size.
 *
 * Returns non-zero correct buffer size or zero by error.
 */
u16 dim_norm_isoc_buffer_size(u16 buf_size, u16 packet_length)
{
        if (!check_packet_length(packet_length))
                return 0;

        return norm_isoc_buffer_size(buf_size, packet_length);
}

/**
 * Retrieves maximal possible correct buffer size for synchronous data type
 * conform to given bytes per frame and not bigger than given buffer size.
 *
 * Returns non-zero correct buffer size or zero by error.
 */
u16 dim_norm_sync_buffer_size(u16 buf_size, u16 bytes_per_frame)
{
        if (!check_bytes_per_frame(bytes_per_frame))
                return 0;

        return norm_sync_buffer_size(buf_size, bytes_per_frame);
}

u8 dim_init_control(struct dim_channel *ch, u8 is_tx, u16 ch_address,
                    u16 max_buffer_size)
{
        return init_ctrl_async(ch, CAT_CT_VAL_CONTROL, is_tx, ch_address,
                               max_buffer_size);
}

u8 dim_init_async(struct dim_channel *ch, u8 is_tx, u16 ch_address,
                  u16 max_buffer_size)
{
        u8 ret = init_ctrl_async(ch, CAT_CT_VAL_ASYNC, is_tx, ch_address,
                                 max_buffer_size);

        if (is_tx && !g.atx_dbr.ch_addr) {
                g.atx_dbr.ch_addr = ch->addr;
                dbrcnt_init(ch->addr, ch->dbr_size);
                dimcb_io_write(&g.dim2->MIEN, bit_mask(20));
        }

        return ret;
}

u8 dim_init_isoc(struct dim_channel *ch, u8 is_tx, u16 ch_address,
                 u16 packet_length)
{
        if (!g.dim_is_initialized || !ch)
                return DIM_ERR_DRIVER_NOT_INITIALIZED;

        if (!check_channel_address(ch_address))
                return DIM_INIT_ERR_CHANNEL_ADDRESS;

        if (!check_packet_length(packet_length))
                return DIM_ERR_BAD_CONFIG;

        ch->dbr_size = packet_length * ISOC_DBR_FACTOR;
        ch->dbr_addr = alloc_dbr(ch->dbr_size);
        if (ch->dbr_addr >= DBR_SIZE)
                return DIM_INIT_ERR_OUT_OF_MEMORY;

        isoc_init(ch, ch_address / 2, packet_length);

        dim2_configure_channel(ch->addr, CAT_CT_VAL_ISOC, is_tx, ch->dbr_addr,
                               ch->dbr_size, packet_length);

        return DIM_NO_ERROR;
}

u8 dim_init_sync(struct dim_channel *ch, u8 is_tx, u16 ch_address,
                 u16 bytes_per_frame)
{
        u16 bd_factor = g.fcnt + 2;

        if (!g.dim_is_initialized || !ch)
                return DIM_ERR_DRIVER_NOT_INITIALIZED;

        if (!check_channel_address(ch_address))
                return DIM_INIT_ERR_CHANNEL_ADDRESS;

        if (!check_bytes_per_frame(bytes_per_frame))
                return DIM_ERR_BAD_CONFIG;

        ch->dbr_size = bytes_per_frame << bd_factor;
        ch->dbr_addr = alloc_dbr(ch->dbr_size);
        if (ch->dbr_addr >= DBR_SIZE)
                return DIM_INIT_ERR_OUT_OF_MEMORY;

        sync_init(ch, ch_address / 2, bytes_per_frame);

        dim2_clear_dbr(ch->dbr_addr, ch->dbr_size);
        dim2_configure_channel(ch->addr, CAT_CT_VAL_SYNC, is_tx,
                               ch->dbr_addr, ch->dbr_size, 0);

        return DIM_NO_ERROR;
}

u8 dim_destroy_channel(struct dim_channel *ch)
{
        if (!g.dim_is_initialized || !ch)
                return DIM_ERR_DRIVER_NOT_INITIALIZED;

        if (ch->addr == g.atx_dbr.ch_addr) {
                dimcb_io_write(&g.dim2->MIEN, 0);
                g.atx_dbr.ch_addr = 0;
        }

        dim2_clear_channel(ch->addr);
        if (ch->dbr_addr < DBR_SIZE)
                free_dbr(ch->dbr_addr, ch->dbr_size);
        ch->dbr_addr = DBR_SIZE;

        return DIM_NO_ERROR;
}

void dim_service_ahb_int_irq(struct dim_channel *const *channels)
{
        bool state_changed;

        if (!g.dim_is_initialized) {
                dim_on_error(DIM_ERR_DRIVER_NOT_INITIALIZED,
                             "DIM is not initialized");
                return;
        }

        if (!channels) {
                dim_on_error(DIM_ERR_DRIVER_NOT_INITIALIZED, "Bad channels");
                return;
        }

        /*
         * Use while-loop and a flag to make sure the age is changed back at
         * least once, otherwise the interrupt may never come if CPU generates
         * interrupt on changing age.
         * This cycle runs not more than number of channels, because
         * channel_service_interrupt() routine doesn't start the channel again.
         */
        do {
                struct dim_channel *const *ch = channels;

                state_changed = false;

                while (*ch) {
                        state_changed |= channel_service_interrupt(*ch);
                        ++ch;
                }
        } while (state_changed);
}

u8 dim_service_channel(struct dim_channel *ch)
{
        if (!g.dim_is_initialized || !ch)
                return DIM_ERR_DRIVER_NOT_INITIALIZED;

        return channel_service(ch);
}

struct dim_ch_state_t *dim_get_channel_state(struct dim_channel *ch,
                                             struct dim_ch_state_t *state_ptr)
{
        if (!ch || !state_ptr)
                return NULL;

        state_ptr->ready = ch->state.level < 2;
        state_ptr->done_buffers = ch->done_sw_buffers_number;

        return state_ptr;
}

bool dim_enqueue_buffer(struct dim_channel *ch, u32 buffer_addr,
                        u16 buffer_size)
{
        if (!ch)
                return dim_on_error(DIM_ERR_DRIVER_NOT_INITIALIZED,
                                    "Bad channel");

        return channel_start(ch, buffer_addr, buffer_size);
}

bool dim_detach_buffers(struct dim_channel *ch, u16 buffers_number)
{
        if (!ch)
                return dim_on_error(DIM_ERR_DRIVER_NOT_INITIALIZED,
                                    "Bad channel");

        return channel_detach_buffers(ch, buffers_number);
}