/*
 * Texas Instruments CPDMA Driver
 *
 * Copyright (C) 2010 Texas Instruments
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/genalloc.h>
#include "davinci_cpdma.h"

/* DMA Registers */
#define CPDMA_TXIDVER           0x00
#define CPDMA_TXCONTROL         0x04
#define CPDMA_TXTEARDOWN        0x08
#define CPDMA_RXIDVER           0x10
#define CPDMA_RXCONTROL         0x14
#define CPDMA_SOFTRESET         0x1c
#define CPDMA_RXTEARDOWN        0x18
#define CPDMA_TX_PRI0_RATE      0x30
#define CPDMA_TXINTSTATRAW      0x80
#define CPDMA_TXINTSTATMASKED   0x84
#define CPDMA_TXINTMASKSET      0x88
#define CPDMA_TXINTMASKCLEAR    0x8c
#define CPDMA_MACINVECTOR       0x90
#define CPDMA_MACEOIVECTOR      0x94
#define CPDMA_RXINTSTATRAW      0xa0
#define CPDMA_RXINTSTATMASKED   0xa4
#define CPDMA_RXINTMASKSET      0xa8
#define CPDMA_RXINTMASKCLEAR    0xac
#define CPDMA_DMAINTSTATRAW     0xb0
#define CPDMA_DMAINTSTATMASKED  0xb4
#define CPDMA_DMAINTMASKSET     0xb8
#define CPDMA_DMAINTMASKCLEAR   0xbc
#define CPDMA_DMAINT_HOSTERR    BIT(1)

/* the following exist only if has_ext_regs is set */
#define CPDMA_DMACONTROL        0x20
#define CPDMA_DMASTATUS         0x24
#define CPDMA_RXBUFFOFS         0x28
#define CPDMA_EM_CONTROL        0x2c

/* Descriptor mode bits */
#define CPDMA_DESC_SOP          BIT(31)
#define CPDMA_DESC_EOP          BIT(30)
#define CPDMA_DESC_OWNER        BIT(29)
#define CPDMA_DESC_EOQ          BIT(28)
#define CPDMA_DESC_TD_COMPLETE  BIT(27)
#define CPDMA_DESC_PASS_CRC     BIT(26)
#define CPDMA_DESC_TO_PORT_EN   BIT(20)
#define CPDMA_TO_PORT_SHIFT     16
#define CPDMA_DESC_PORT_MASK    (BIT(18) | BIT(17) | BIT(16))
#define CPDMA_DESC_CRC_LEN      4

#define CPDMA_TEARDOWN_VALUE    0xfffffffc

#define CPDMA_MAX_RLIM_CNT      16384

struct cpdma_desc {
        /* hardware fields */
        u32                     hw_next;
        u32                     hw_buffer;
        u32                     hw_len;
        u32                     hw_mode;
        /* software fields */
        void                    *sw_token;
        u32                     sw_buffer;
        u32                     sw_len;
};

struct cpdma_desc_pool {
        phys_addr_t             phys;
        dma_addr_t              hw_addr;
        void __iomem            *iomap;         /* ioremap map */
        void                    *cpumap;        /* dma_alloc map */
        int                     desc_size, mem_size;
        int                     num_desc;
        struct device           *dev;
        struct gen_pool         *gen_pool;
};

enum cpdma_state {
        CPDMA_STATE_IDLE,
        CPDMA_STATE_ACTIVE,
        CPDMA_STATE_TEARDOWN,
};

struct cpdma_ctlr {
        enum cpdma_state        state;
        struct cpdma_params     params;
        struct device           *dev;
        struct cpdma_desc_pool  *pool;
        spinlock_t              lock;
        struct cpdma_chan       *channels[2 * CPDMA_MAX_CHANNELS];
        int chan_num;
        int                     num_rx_desc; /* RX descriptors number */
        int                     num_tx_desc; /* TX descriptors number */
};

struct cpdma_chan {
        struct cpdma_desc __iomem       *head, *tail;
        void __iomem                    *hdp, *cp, *rxfree;
        enum cpdma_state                state;
        struct cpdma_ctlr               *ctlr;
        int                             chan_num;
        spinlock_t                      lock;
        int                             count;
        u32                             desc_num;
        u32                             mask;
        cpdma_handler_fn                handler;
        enum dma_data_direction         dir;
        struct cpdma_chan_stats         stats;
        /* offsets into dmaregs */
        int     int_set, int_clear, td;
        int                             weight;
        u32                             rate_factor;
        u32                             rate;
};

struct cpdma_control_info {
        u32             reg;
        u32             shift, mask;
        int             access;
#define ACCESS_RO       BIT(0)
#define ACCESS_WO       BIT(1)
#define ACCESS_RW       (ACCESS_RO | ACCESS_WO)
};

static struct cpdma_control_info controls[] = {
        [CPDMA_TX_RLIM]           = {CPDMA_DMACONTROL,  8,  0xffff, ACCESS_RW},
        [CPDMA_CMD_IDLE]          = {CPDMA_DMACONTROL,  3,  1,      ACCESS_WO},
        [CPDMA_COPY_ERROR_FRAMES] = {CPDMA_DMACONTROL,  4,  1,      ACCESS_RW},
        [CPDMA_RX_OFF_LEN_UPDATE] = {CPDMA_DMACONTROL,  2,  1,      ACCESS_RW},
        [CPDMA_RX_OWNERSHIP_FLIP] = {CPDMA_DMACONTROL,  1,  1,      ACCESS_RW},
        [CPDMA_TX_PRIO_FIXED]     = {CPDMA_DMACONTROL,  0,  1,      ACCESS_RW},
        [CPDMA_STAT_IDLE]         = {CPDMA_DMASTATUS,   31, 1,      ACCESS_RO},
        [CPDMA_STAT_TX_ERR_CODE]  = {CPDMA_DMASTATUS,   20, 0xf,    ACCESS_RW},
        [CPDMA_STAT_TX_ERR_CHAN]  = {CPDMA_DMASTATUS,   16, 0x7,    ACCESS_RW},
        [CPDMA_STAT_RX_ERR_CODE]  = {CPDMA_DMASTATUS,   12, 0xf,    ACCESS_RW},
        [CPDMA_STAT_RX_ERR_CHAN]  = {CPDMA_DMASTATUS,   8,  0x7,    ACCESS_RW},
        [CPDMA_RX_BUFFER_OFFSET]  = {CPDMA_RXBUFFOFS,   0,  0xffff, ACCESS_RW},
};

#define tx_chan_num(chan)       (chan)
#define rx_chan_num(chan)       ((chan) + CPDMA_MAX_CHANNELS)
#define is_rx_chan(chan)        ((chan)->chan_num >= CPDMA_MAX_CHANNELS)
#define is_tx_chan(chan)        (!is_rx_chan(chan))
#define __chan_linear(chan_num) ((chan_num) & (CPDMA_MAX_CHANNELS - 1))
#define chan_linear(chan)       __chan_linear((chan)->chan_num)

/* The following make access to common cpdma_ctlr params more readable */
#define dmaregs         params.dmaregs
#define num_chan        params.num_chan

/* various accessors */
#define dma_reg_read(ctlr, ofs)         readl((ctlr)->dmaregs + (ofs))
#define chan_read(chan, fld)            readl((chan)->fld)
#define desc_read(desc, fld)            readl(&(desc)->fld)
#define dma_reg_write(ctlr, ofs, v)     writel(v, (ctlr)->dmaregs + (ofs))
#define chan_write(chan, fld, v)        writel(v, (chan)->fld)
#define desc_write(desc, fld, v)        writel((u32)(v), &(desc)->fld)

#define cpdma_desc_to_port(chan, mode, directed)                        \
        do {                                                            \
                if (!is_rx_chan(chan) && ((directed == 1) ||            \
                                          (directed == 2)))             \
                        mode |= (CPDMA_DESC_TO_PORT_EN |                \
                                 (directed << CPDMA_TO_PORT_SHIFT));    \
        } while (0)

static void cpdma_desc_pool_destroy(struct cpdma_ctlr *ctlr)
{
        struct cpdma_desc_pool *pool = ctlr->pool;

        if (!pool)
                return;

        WARN(gen_pool_size(pool->gen_pool) != gen_pool_avail(pool->gen_pool),
             "cpdma_desc_pool size %d != avail %d",
             gen_pool_size(pool->gen_pool),
             gen_pool_avail(pool->gen_pool));
        if (pool->cpumap)
                dma_free_coherent(ctlr->dev, pool->mem_size, pool->cpumap,
                                  pool->phys);
}

/*
 * Utility constructs for a cpdma descriptor pool.  Some devices (e.g. davinci
 * emac) have dedicated on-chip memory for these descriptors.  Some other
 * devices (e.g. cpsw switches) use plain old memory.  Descriptor pools
 * abstract out these details
 */
int cpdma_desc_pool_create(struct cpdma_ctlr *ctlr)
{
        struct cpdma_params *cpdma_params = &ctlr->params;
        struct cpdma_desc_pool *pool;
        int ret = -ENOMEM;

        pool = devm_kzalloc(ctlr->dev, sizeof(*pool), GFP_KERNEL);
        if (!pool)
                goto gen_pool_create_fail;
        ctlr->pool = pool;

        pool->mem_size  = cpdma_params->desc_mem_size;
        pool->desc_size = ALIGN(sizeof(struct cpdma_desc),
                                cpdma_params->desc_align);
        pool->num_desc  = pool->mem_size / pool->desc_size;

        if (cpdma_params->descs_pool_size) {
                /* recalculate memory size required cpdma descriptor pool
                 * basing on number of descriptors specified by user and
                 * if memory size > CPPI internal RAM size (desc_mem_size)
                 * then switch to use DDR
                 */
                pool->num_desc = cpdma_params->descs_pool_size;
                pool->mem_size = pool->desc_size * pool->num_desc;
                if (pool->mem_size > cpdma_params->desc_mem_size)
                        cpdma_params->desc_mem_phys = 0;
        }

        pool->gen_pool = devm_gen_pool_create(ctlr->dev, ilog2(pool->desc_size),
                                              -1, "cpdma");
        if (IS_ERR(pool->gen_pool)) {
                ret = PTR_ERR(pool->gen_pool);
                dev_err(ctlr->dev, "pool create failed %d\n", ret);
                goto gen_pool_create_fail;
        }

        if (cpdma_params->desc_mem_phys) {
                pool->phys  = cpdma_params->desc_mem_phys;
                pool->iomap = devm_ioremap(ctlr->dev, pool->phys,
                                           pool->mem_size);
                pool->hw_addr = cpdma_params->desc_hw_addr;
        } else {
                pool->cpumap = dma_alloc_coherent(ctlr->dev,  pool->mem_size,
                                                  &pool->hw_addr, GFP_KERNEL);
                pool->iomap = (void __iomem __force *)pool->cpumap;
                pool->phys = pool->hw_addr; /* assumes no IOMMU, don't use this value */
        }

        if (!pool->iomap)
                goto gen_pool_create_fail;

        ret = gen_pool_add_virt(pool->gen_pool, (unsigned long)pool->iomap,
                                pool->phys, pool->mem_size, -1);
        if (ret < 0) {
                dev_err(ctlr->dev, "pool add failed %d\n", ret);
                goto gen_pool_add_virt_fail;
        }

        return 0;

gen_pool_add_virt_fail:
        cpdma_desc_pool_destroy(ctlr);
gen_pool_create_fail:
        ctlr->pool = NULL;
        return ret;
}

static inline dma_addr_t desc_phys(struct cpdma_desc_pool *pool,
                  struct cpdma_desc __iomem *desc)
{
        if (!desc)
                return 0;
        return pool->hw_addr + (__force long)desc - (__force long)pool->iomap;
}

static inline struct cpdma_desc __iomem *
desc_from_phys(struct cpdma_desc_pool *pool, dma_addr_t dma)
{
        return dma ? pool->iomap + dma - pool->hw_addr : NULL;
}

static struct cpdma_desc __iomem *
cpdma_desc_alloc(struct cpdma_desc_pool *pool)
{
        return (struct cpdma_desc __iomem *)
                gen_pool_alloc(pool->gen_pool, pool->desc_size);
}

static void cpdma_desc_free(struct cpdma_desc_pool *pool,
                            struct cpdma_desc __iomem *desc, int num_desc)
{
        gen_pool_free(pool->gen_pool, (unsigned long)desc, pool->desc_size);
}

static int _cpdma_control_set(struct cpdma_ctlr *ctlr, int control, int value)
{
        struct cpdma_control_info *info = &controls[control];
        u32 val;

        if (!ctlr->params.has_ext_regs)
                return -ENOTSUPP;

        if (ctlr->state != CPDMA_STATE_ACTIVE)
                return -EINVAL;

        if (control < 0 || control >= ARRAY_SIZE(controls))
                return -ENOENT;

        if ((info->access & ACCESS_WO) != ACCESS_WO)
                return -EPERM;

        val  = dma_reg_read(ctlr, info->reg);
        val &= ~(info->mask << info->shift);
        val |= (value & info->mask) << info->shift;
        dma_reg_write(ctlr, info->reg, val);

        return 0;
}

static int _cpdma_control_get(struct cpdma_ctlr *ctlr, int control)
{
        struct cpdma_control_info *info = &controls[control];
        int ret;

        if (!ctlr->params.has_ext_regs)
                return -ENOTSUPP;

        if (ctlr->state != CPDMA_STATE_ACTIVE)
                return -EINVAL;

        if (control < 0 || control >= ARRAY_SIZE(controls))
                return -ENOENT;

        if ((info->access & ACCESS_RO) != ACCESS_RO)
                return -EPERM;

        ret = (dma_reg_read(ctlr, info->reg) >> info->shift) & info->mask;
        return ret;
}

/* cpdma_chan_set_chan_shaper - set shaper for a channel
 * Has to be called under ctlr lock
 */
static int cpdma_chan_set_chan_shaper(struct cpdma_chan *chan)
{
        struct cpdma_ctlr *ctlr = chan->ctlr;
        u32 rate_reg;
        u32 rmask;
        int ret;

        if (!chan->rate)
                return 0;

        rate_reg = CPDMA_TX_PRI0_RATE + 4 * chan->chan_num;
        dma_reg_write(ctlr, rate_reg, chan->rate_factor);

        rmask = _cpdma_control_get(ctlr, CPDMA_TX_RLIM);
        rmask |= chan->mask;

        ret = _cpdma_control_set(ctlr, CPDMA_TX_RLIM, rmask);
        return ret;
}

static int cpdma_chan_on(struct cpdma_chan *chan)
{
        struct cpdma_ctlr *ctlr = chan->ctlr;
        struct cpdma_desc_pool  *pool = ctlr->pool;
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);
        if (chan->state != CPDMA_STATE_IDLE) {
                spin_unlock_irqrestore(&chan->lock, flags);
                return -EBUSY;
        }
        if (ctlr->state != CPDMA_STATE_ACTIVE) {
                spin_unlock_irqrestore(&chan->lock, flags);
                return -EINVAL;
        }
        dma_reg_write(ctlr, chan->int_set, chan->mask);
        chan->state = CPDMA_STATE_ACTIVE;
        if (chan->head) {
                chan_write(chan, hdp, desc_phys(pool, chan->head));
                if (chan->rxfree)
                        chan_write(chan, rxfree, chan->count);
        }

        spin_unlock_irqrestore(&chan->lock, flags);
        return 0;
}

/* cpdma_chan_fit_rate - set rate for a channel and check if it's possible.
 * rmask - mask of rate limited channels
 * Returns min rate in Kb/s
 */
static int cpdma_chan_fit_rate(struct cpdma_chan *ch, u32 rate,
                               u32 *rmask, int *prio_mode)
{
        struct cpdma_ctlr *ctlr = ch->ctlr;
        struct cpdma_chan *chan;
        u32 old_rate = ch->rate;
        u32 new_rmask = 0;
        int rlim = 1;
        int i;

        *prio_mode = 0;
        for (i = tx_chan_num(0); i < tx_chan_num(CPDMA_MAX_CHANNELS); i++) {
                chan = ctlr->channels[i];
                if (!chan) {
                        rlim = 0;
                        continue;
                }

                if (chan == ch)
                        chan->rate = rate;

                if (chan->rate) {
                        if (rlim) {
                                new_rmask |= chan->mask;
                        } else {
                                ch->rate = old_rate;
                                dev_err(ctlr->dev, "Prev channel of %dch is not rate limited\n",
                                        chan->chan_num);
                                return -EINVAL;
                        }
                } else {
                        *prio_mode = 1;
                        rlim = 0;
                }
        }

        *rmask = new_rmask;
        return 0;
}

static u32 cpdma_chan_set_factors(struct cpdma_ctlr *ctlr,
                                  struct cpdma_chan *ch)
{
        u32 delta = UINT_MAX, prev_delta = UINT_MAX, best_delta = UINT_MAX;
        u32 best_send_cnt = 0, best_idle_cnt = 0;
        u32 new_rate, best_rate = 0, rate_reg;
        u64 send_cnt, idle_cnt;
        u32 min_send_cnt, freq;
        u64 divident, divisor;

        if (!ch->rate) {
                ch->rate_factor = 0;
                goto set_factor;
        }

        freq = ctlr->params.bus_freq_mhz * 1000 * 32;
        if (!freq) {
                dev_err(ctlr->dev, "The bus frequency is not set\n");
                return -EINVAL;
        }

        min_send_cnt = freq - ch->rate;
        send_cnt = DIV_ROUND_UP(min_send_cnt, ch->rate);
        while (send_cnt <= CPDMA_MAX_RLIM_CNT) {
                divident = ch->rate * send_cnt;
                divisor = min_send_cnt;
                idle_cnt = DIV_ROUND_CLOSEST_ULL(divident, divisor);

                divident = freq * idle_cnt;
                divisor = idle_cnt + send_cnt;
                new_rate = DIV_ROUND_CLOSEST_ULL(divident, divisor);

                delta = new_rate >= ch->rate ? new_rate - ch->rate : delta;
                if (delta < best_delta) {
                        best_delta = delta;
                        best_send_cnt = send_cnt;
                        best_idle_cnt = idle_cnt;
                        best_rate = new_rate;

                        if (!delta)
                                break;
                }

                if (prev_delta >= delta) {
                        prev_delta = delta;
                        send_cnt++;
                        continue;
                }

                idle_cnt++;
                divident = freq * idle_cnt;
                send_cnt = DIV_ROUND_CLOSEST_ULL(divident, ch->rate);
                send_cnt -= idle_cnt;
                prev_delta = UINT_MAX;
        }

        ch->rate = best_rate;
        ch->rate_factor = best_send_cnt | (best_idle_cnt << 16);

set_factor:
        rate_reg = CPDMA_TX_PRI0_RATE + 4 * ch->chan_num;
        dma_reg_write(ctlr, rate_reg, ch->rate_factor);
        return 0;
}

struct cpdma_ctlr *cpdma_ctlr_create(struct cpdma_params *params)
{
        struct cpdma_ctlr *ctlr;

        ctlr = devm_kzalloc(params->dev, sizeof(*ctlr), GFP_KERNEL);
        if (!ctlr)
                return NULL;

        ctlr->state = CPDMA_STATE_IDLE;
        ctlr->params = *params;
        ctlr->dev = params->dev;
        ctlr->chan_num = 0;
        spin_lock_init(&ctlr->lock);

        if (cpdma_desc_pool_create(ctlr))
                return NULL;
        /* split pool equally between RX/TX by default */
        ctlr->num_tx_desc = ctlr->pool->num_desc / 2;
        ctlr->num_rx_desc = ctlr->pool->num_desc - ctlr->num_tx_desc;

        if (WARN_ON(ctlr->num_chan > CPDMA_MAX_CHANNELS))
                ctlr->num_chan = CPDMA_MAX_CHANNELS;
        return ctlr;
}
EXPORT_SYMBOL_GPL(cpdma_ctlr_create);

int cpdma_ctlr_start(struct cpdma_ctlr *ctlr)
{
        struct cpdma_chan *chan;
        unsigned long flags;
        int i, prio_mode;

        spin_lock_irqsave(&ctlr->lock, flags);
        if (ctlr->state != CPDMA_STATE_IDLE) {
                spin_unlock_irqrestore(&ctlr->lock, flags);
                return -EBUSY;
        }

        if (ctlr->params.has_soft_reset) {
                unsigned timeout = 10 * 100;

                dma_reg_write(ctlr, CPDMA_SOFTRESET, 1);
                while (timeout) {
                        if (dma_reg_read(ctlr, CPDMA_SOFTRESET) == 0)
                                break;
                        udelay(10);
                        timeout--;
                }
                WARN_ON(!timeout);
        }

        for (i = 0; i < ctlr->num_chan; i++) {
                writel(0, ctlr->params.txhdp + 4 * i);
                writel(0, ctlr->params.rxhdp + 4 * i);
                writel(0, ctlr->params.txcp + 4 * i);
                writel(0, ctlr->params.rxcp + 4 * i);
        }

        dma_reg_write(ctlr, CPDMA_RXINTMASKCLEAR, 0xffffffff);
        dma_reg_write(ctlr, CPDMA_TXINTMASKCLEAR, 0xffffffff);

        dma_reg_write(ctlr, CPDMA_TXCONTROL, 1);
        dma_reg_write(ctlr, CPDMA_RXCONTROL, 1);

        ctlr->state = CPDMA_STATE_ACTIVE;

        prio_mode = 0;
        for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++) {
                chan = ctlr->channels[i];
                if (chan) {
                        cpdma_chan_set_chan_shaper(chan);
                        cpdma_chan_on(chan);

                        /* off prio mode if all tx channels are rate limited */
                        if (is_tx_chan(chan) && !chan->rate)
                                prio_mode = 1;
                }
        }

        _cpdma_control_set(ctlr, CPDMA_TX_PRIO_FIXED, prio_mode);
        _cpdma_control_set(ctlr, CPDMA_RX_BUFFER_OFFSET, 0);

        spin_unlock_irqrestore(&ctlr->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_ctlr_start);

int cpdma_ctlr_stop(struct cpdma_ctlr *ctlr)
{
        unsigned long flags;
        int i;

        spin_lock_irqsave(&ctlr->lock, flags);
        if (ctlr->state != CPDMA_STATE_ACTIVE) {
                spin_unlock_irqrestore(&ctlr->lock, flags);
                return -EINVAL;
        }

        ctlr->state = CPDMA_STATE_TEARDOWN;
        spin_unlock_irqrestore(&ctlr->lock, flags);

        for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++) {
                if (ctlr->channels[i])
                        cpdma_chan_stop(ctlr->channels[i]);
        }

        spin_lock_irqsave(&ctlr->lock, flags);
        dma_reg_write(ctlr, CPDMA_RXINTMASKCLEAR, 0xffffffff);
        dma_reg_write(ctlr, CPDMA_TXINTMASKCLEAR, 0xffffffff);

        dma_reg_write(ctlr, CPDMA_TXCONTROL, 0);
        dma_reg_write(ctlr, CPDMA_RXCONTROL, 0);

        ctlr->state = CPDMA_STATE_IDLE;

        spin_unlock_irqrestore(&ctlr->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_ctlr_stop);

int cpdma_ctlr_destroy(struct cpdma_ctlr *ctlr)
{
        int ret = 0, i;

        if (!ctlr)
                return -EINVAL;

        if (ctlr->state != CPDMA_STATE_IDLE)
                cpdma_ctlr_stop(ctlr);

        for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++)
                cpdma_chan_destroy(ctlr->channels[i]);

        cpdma_desc_pool_destroy(ctlr);
        return ret;
}
EXPORT_SYMBOL_GPL(cpdma_ctlr_destroy);

int cpdma_ctlr_int_ctrl(struct cpdma_ctlr *ctlr, bool enable)
{
        unsigned long flags;
        int i;

        spin_lock_irqsave(&ctlr->lock, flags);
        if (ctlr->state != CPDMA_STATE_ACTIVE) {
                spin_unlock_irqrestore(&ctlr->lock, flags);
                return -EINVAL;
        }

        for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++) {
                if (ctlr->channels[i])
                        cpdma_chan_int_ctrl(ctlr->channels[i], enable);
        }

        spin_unlock_irqrestore(&ctlr->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_ctlr_int_ctrl);

void cpdma_ctlr_eoi(struct cpdma_ctlr *ctlr, u32 value)
{
        dma_reg_write(ctlr, CPDMA_MACEOIVECTOR, value);
}
EXPORT_SYMBOL_GPL(cpdma_ctlr_eoi);

u32 cpdma_ctrl_rxchs_state(struct cpdma_ctlr *ctlr)
{
        return dma_reg_read(ctlr, CPDMA_RXINTSTATMASKED);
}
EXPORT_SYMBOL_GPL(cpdma_ctrl_rxchs_state);

u32 cpdma_ctrl_txchs_state(struct cpdma_ctlr *ctlr)
{
        return dma_reg_read(ctlr, CPDMA_TXINTSTATMASKED);
}
EXPORT_SYMBOL_GPL(cpdma_ctrl_txchs_state);

static void cpdma_chan_set_descs(struct cpdma_ctlr *ctlr,
                                 int rx, int desc_num,
                                 int per_ch_desc)
{
        struct cpdma_chan *chan, *most_chan = NULL;
        int desc_cnt = desc_num;
        int most_dnum = 0;
        int min, max, i;

        if (!desc_num)
                return;

        if (rx) {
                min = rx_chan_num(0);
                max = rx_chan_num(CPDMA_MAX_CHANNELS);
        } else {
                min = tx_chan_num(0);
                max = tx_chan_num(CPDMA_MAX_CHANNELS);
        }

        for (i = min; i < max; i++) {
                chan = ctlr->channels[i];
                if (!chan)
                        continue;

                if (chan->weight)
                        chan->desc_num = (chan->weight * desc_num) / 100;
                else
                        chan->desc_num = per_ch_desc;

                desc_cnt -= chan->desc_num;

                if (most_dnum < chan->desc_num) {
                        most_dnum = chan->desc_num;
                        most_chan = chan;
                }
        }
        /* use remains */
        if (most_chan)
                most_chan->desc_num += desc_cnt;
}

/**
 * cpdma_chan_split_pool - Splits ctrl pool between all channels.
 * Has to be called under ctlr lock
 */
int cpdma_chan_split_pool(struct cpdma_ctlr *ctlr)
{
        int tx_per_ch_desc = 0, rx_per_ch_desc = 0;
        int free_rx_num = 0, free_tx_num = 0;
        int rx_weight = 0, tx_weight = 0;
        int tx_desc_num, rx_desc_num;
        struct cpdma_chan *chan;
        int i;

        if (!ctlr->chan_num)
                return 0;

        for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++) {
                chan = ctlr->channels[i];
                if (!chan)
                        continue;

                if (is_rx_chan(chan)) {
                        if (!chan->weight)
                                free_rx_num++;
                        rx_weight += chan->weight;
                } else {
                        if (!chan->weight)
                                free_tx_num++;
                        tx_weight += chan->weight;
                }
        }

        if (rx_weight > 100 || tx_weight > 100)
                return -EINVAL;

        tx_desc_num = ctlr->num_tx_desc;
        rx_desc_num = ctlr->num_rx_desc;

        if (free_tx_num) {
                tx_per_ch_desc = tx_desc_num - (tx_weight * tx_desc_num) / 100;
                tx_per_ch_desc /= free_tx_num;
        }
        if (free_rx_num) {
                rx_per_ch_desc = rx_desc_num - (rx_weight * rx_desc_num) / 100;
                rx_per_ch_desc /= free_rx_num;
        }

        cpdma_chan_set_descs(ctlr, 0, tx_desc_num, tx_per_ch_desc);
        cpdma_chan_set_descs(ctlr, 1, rx_desc_num, rx_per_ch_desc);

        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_chan_split_pool);


/* cpdma_chan_set_weight - set weight of a channel in percentage.
 * Tx and Rx channels have separate weights. That is 100% for RX
 * and 100% for Tx. The weight is used to split cpdma resources
 * in correct proportion required by the channels, including number
 * of descriptors. The channel rate is not enough to know the
 * weight of a channel as the maximum rate of an interface is needed.
 * If weight = 0, then channel uses rest of descriptors leaved by
 * weighted channels.
 */
int cpdma_chan_set_weight(struct cpdma_chan *ch, int weight)
{
        struct cpdma_ctlr *ctlr = ch->ctlr;
        unsigned long flags, ch_flags;
        int ret;

        spin_lock_irqsave(&ctlr->lock, flags);
        spin_lock_irqsave(&ch->lock, ch_flags);
        if (ch->weight == weight) {
                spin_unlock_irqrestore(&ch->lock, ch_flags);
                spin_unlock_irqrestore(&ctlr->lock, flags);
                return 0;
        }
        ch->weight = weight;
        spin_unlock_irqrestore(&ch->lock, ch_flags);

        /* re-split pool using new channel weight */
        ret = cpdma_chan_split_pool(ctlr);
        spin_unlock_irqrestore(&ctlr->lock, flags);
        return ret;
}
EXPORT_SYMBOL_GPL(cpdma_chan_set_weight);

/* cpdma_chan_get_min_rate - get minimum allowed rate for channel
 * Should be called before cpdma_chan_set_rate.
 * Returns min rate in Kb/s
 */
u32 cpdma_chan_get_min_rate(struct cpdma_ctlr *ctlr)
{
        unsigned int divident, divisor;

        divident = ctlr->params.bus_freq_mhz * 32 * 1000;
        divisor = 1 + CPDMA_MAX_RLIM_CNT;

        return DIV_ROUND_UP(divident, divisor);
}
EXPORT_SYMBOL_GPL(cpdma_chan_get_min_rate);

/* cpdma_chan_set_rate - limits bandwidth for transmit channel.
 * The bandwidth * limited channels have to be in order beginning from lowest.
 * ch - transmit channel the bandwidth is configured for
 * rate - bandwidth in Kb/s, if 0 - then off shaper
 */
int cpdma_chan_set_rate(struct cpdma_chan *ch, u32 rate)
{
        unsigned long flags, ch_flags;
        struct cpdma_ctlr *ctlr;
        int ret, prio_mode;
        u32 rmask;

        if (!ch || !is_tx_chan(ch))
                return -EINVAL;

        if (ch->rate == rate)
                return rate;

        ctlr = ch->ctlr;
        spin_lock_irqsave(&ctlr->lock, flags);
        spin_lock_irqsave(&ch->lock, ch_flags);

        ret = cpdma_chan_fit_rate(ch, rate, &rmask, &prio_mode);
        if (ret)
                goto err;

        ret = cpdma_chan_set_factors(ctlr, ch);
        if (ret)
                goto err;

        spin_unlock_irqrestore(&ch->lock, ch_flags);

        /* on shapers */
        _cpdma_control_set(ctlr, CPDMA_TX_RLIM, rmask);
        _cpdma_control_set(ctlr, CPDMA_TX_PRIO_FIXED, prio_mode);
        spin_unlock_irqrestore(&ctlr->lock, flags);
        return ret;

err:
        spin_unlock_irqrestore(&ch->lock, ch_flags);
        spin_unlock_irqrestore(&ctlr->lock, flags);
        return ret;
}
EXPORT_SYMBOL_GPL(cpdma_chan_set_rate);

u32 cpdma_chan_get_rate(struct cpdma_chan *ch)
{
        unsigned long flags;
        u32 rate;

        spin_lock_irqsave(&ch->lock, flags);
        rate = ch->rate;
        spin_unlock_irqrestore(&ch->lock, flags);

        return rate;
}
EXPORT_SYMBOL_GPL(cpdma_chan_get_rate);

struct cpdma_chan *cpdma_chan_create(struct cpdma_ctlr *ctlr, int chan_num,
                                     cpdma_handler_fn handler, int rx_type)
{
        int offset = chan_num * 4;
        struct cpdma_chan *chan;
        unsigned long flags;

        chan_num = rx_type ? rx_chan_num(chan_num) : tx_chan_num(chan_num);

        if (__chan_linear(chan_num) >= ctlr->num_chan)
                return NULL;

        chan = devm_kzalloc(ctlr->dev, sizeof(*chan), GFP_KERNEL);
        if (!chan)
                return ERR_PTR(-ENOMEM);

        spin_lock_irqsave(&ctlr->lock, flags);
        if (ctlr->channels[chan_num]) {
                spin_unlock_irqrestore(&ctlr->lock, flags);
                devm_kfree(ctlr->dev, chan);
                return ERR_PTR(-EBUSY);
        }

        chan->ctlr      = ctlr;
        chan->state     = CPDMA_STATE_IDLE;
        chan->chan_num  = chan_num;
        chan->handler   = handler;
        chan->rate      = 0;
        chan->weight    = 0;

        if (is_rx_chan(chan)) {
                chan->hdp       = ctlr->params.rxhdp + offset;
                chan->cp        = ctlr->params.rxcp + offset;
                chan->rxfree    = ctlr->params.rxfree + offset;
                chan->int_set   = CPDMA_RXINTMASKSET;
                chan->int_clear = CPDMA_RXINTMASKCLEAR;
                chan->td        = CPDMA_RXTEARDOWN;
                chan->dir       = DMA_FROM_DEVICE;
        } else {
                chan->hdp       = ctlr->params.txhdp + offset;
                chan->cp        = ctlr->params.txcp + offset;
                chan->int_set   = CPDMA_TXINTMASKSET;
                chan->int_clear = CPDMA_TXINTMASKCLEAR;
                chan->td        = CPDMA_TXTEARDOWN;
                chan->dir       = DMA_TO_DEVICE;
        }
        chan->mask = BIT(chan_linear(chan));

        spin_lock_init(&chan->lock);

        ctlr->channels[chan_num] = chan;
        ctlr->chan_num++;

        cpdma_chan_split_pool(ctlr);

        spin_unlock_irqrestore(&ctlr->lock, flags);
        return chan;
}
EXPORT_SYMBOL_GPL(cpdma_chan_create);

int cpdma_chan_get_rx_buf_num(struct cpdma_chan *chan)
{
        unsigned long flags;
        int desc_num;

        spin_lock_irqsave(&chan->lock, flags);
        desc_num = chan->desc_num;
        spin_unlock_irqrestore(&chan->lock, flags);

        return desc_num;
}
EXPORT_SYMBOL_GPL(cpdma_chan_get_rx_buf_num);

int cpdma_chan_destroy(struct cpdma_chan *chan)
{
        struct cpdma_ctlr *ctlr;
        unsigned long flags;

        if (!chan)
                return -EINVAL;
        ctlr = chan->ctlr;

        spin_lock_irqsave(&ctlr->lock, flags);
        if (chan->state != CPDMA_STATE_IDLE)
                cpdma_chan_stop(chan);
        ctlr->channels[chan->chan_num] = NULL;
        ctlr->chan_num--;
        devm_kfree(ctlr->dev, chan);
        cpdma_chan_split_pool(ctlr);

        spin_unlock_irqrestore(&ctlr->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_chan_destroy);

int cpdma_chan_get_stats(struct cpdma_chan *chan,
                         struct cpdma_chan_stats *stats)
{
        unsigned long flags;
        if (!chan)
                return -EINVAL;
        spin_lock_irqsave(&chan->lock, flags);
        memcpy(stats, &chan->stats, sizeof(*stats));
        spin_unlock_irqrestore(&chan->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_chan_get_stats);

static void __cpdma_chan_submit(struct cpdma_chan *chan,
                                struct cpdma_desc __iomem *desc)
{
        struct cpdma_ctlr               *ctlr = chan->ctlr;
        struct cpdma_desc __iomem       *prev = chan->tail;
        struct cpdma_desc_pool          *pool = ctlr->pool;
        dma_addr_t                      desc_dma;

        u32                             mode;

        desc_dma = desc_phys(pool, desc);

        /* simple case - idle channel */
        if (!chan->head) {
                chan->stats.head_enqueue++;
                chan->head = desc;
                chan->tail = desc;
                if (chan->state == CPDMA_STATE_ACTIVE)
                        chan_write(chan, hdp, desc_dma);
                return;
        }

        /* first chain the descriptor at the tail of the list */
        desc_write(prev, hw_next, desc_dma);
        chan->tail = desc;
        chan->stats.tail_enqueue++;

        /* next check if EOQ has been triggered already */
        mode = desc_read(prev, hw_mode);
        if (((mode & (CPDMA_DESC_EOQ | CPDMA_DESC_OWNER)) == CPDMA_DESC_EOQ) &&
            (chan->state == CPDMA_STATE_ACTIVE)) {
                desc_write(prev, hw_mode, mode & ~CPDMA_DESC_EOQ);
                chan_write(chan, hdp, desc_dma);
                chan->stats.misqueued++;
        }
}

int cpdma_chan_submit(struct cpdma_chan *chan, void *token, void *data,
                      int len, int directed)
{
        struct cpdma_ctlr               *ctlr = chan->ctlr;
        struct cpdma_desc __iomem       *desc;
        dma_addr_t                      buffer;
        unsigned long                   flags;
        u32                             mode;
        int                             ret = 0;

        spin_lock_irqsave(&chan->lock, flags);

        if (chan->state == CPDMA_STATE_TEARDOWN) {
                ret = -EINVAL;
                goto unlock_ret;
        }

        if (chan->count >= chan->desc_num)      {
                chan->stats.desc_alloc_fail++;
                ret = -ENOMEM;
                goto unlock_ret;
        }

        desc = cpdma_desc_alloc(ctlr->pool);
        if (!desc) {
                chan->stats.desc_alloc_fail++;
                ret = -ENOMEM;
                goto unlock_ret;
        }

        if (len < ctlr->params.min_packet_size) {
                len = ctlr->params.min_packet_size;
                chan->stats.runt_transmit_buff++;
        }

        buffer = dma_map_single(ctlr->dev, data, len, chan->dir);
        ret = dma_mapping_error(ctlr->dev, buffer);
        if (ret) {
                cpdma_desc_free(ctlr->pool, desc, 1);
                ret = -EINVAL;
                goto unlock_ret;
        }

        mode = CPDMA_DESC_OWNER | CPDMA_DESC_SOP | CPDMA_DESC_EOP;
        cpdma_desc_to_port(chan, mode, directed);

        /* Relaxed IO accessors can be used here as there is read barrier
         * at the end of write sequence.
         */
        writel_relaxed(0, &desc->hw_next);
        writel_relaxed(buffer, &desc->hw_buffer);
        writel_relaxed(len, &desc->hw_len);
        writel_relaxed(mode | len, &desc->hw_mode);
        writel_relaxed(token, &desc->sw_token);
        writel_relaxed(buffer, &desc->sw_buffer);
        writel_relaxed(len, &desc->sw_len);
        desc_read(desc, sw_len);

        __cpdma_chan_submit(chan, desc);

        if (chan->state == CPDMA_STATE_ACTIVE && chan->rxfree)
                chan_write(chan, rxfree, 1);

        chan->count++;

unlock_ret:
        spin_unlock_irqrestore(&chan->lock, flags);
        return ret;
}
EXPORT_SYMBOL_GPL(cpdma_chan_submit);

bool cpdma_check_free_tx_desc(struct cpdma_chan *chan)
{
        struct cpdma_ctlr       *ctlr = chan->ctlr;
        struct cpdma_desc_pool  *pool = ctlr->pool;
        bool                    free_tx_desc;
        unsigned long           flags;

        spin_lock_irqsave(&chan->lock, flags);
        free_tx_desc = (chan->count < chan->desc_num) &&
                         gen_pool_avail(pool->gen_pool);
        spin_unlock_irqrestore(&chan->lock, flags);
        return free_tx_desc;
}
EXPORT_SYMBOL_GPL(cpdma_check_free_tx_desc);

static void __cpdma_chan_free(struct cpdma_chan *chan,
                              struct cpdma_desc __iomem *desc,
                              int outlen, int status)
{
        struct cpdma_ctlr               *ctlr = chan->ctlr;
        struct cpdma_desc_pool          *pool = ctlr->pool;
        dma_addr_t                      buff_dma;
        int                             origlen;
        void                            *token;

        token      = (void *)desc_read(desc, sw_token);
        buff_dma   = desc_read(desc, sw_buffer);
        origlen    = desc_read(desc, sw_len);

        dma_unmap_single(ctlr->dev, buff_dma, origlen, chan->dir);
        cpdma_desc_free(pool, desc, 1);
        (*chan->handler)(token, outlen, status);
}

static int __cpdma_chan_process(struct cpdma_chan *chan)
{
        struct cpdma_ctlr               *ctlr = chan->ctlr;
        struct cpdma_desc __iomem       *desc;
        int                             status, outlen;
        int                             cb_status = 0;
        struct cpdma_desc_pool          *pool = ctlr->pool;
        dma_addr_t                      desc_dma;
        unsigned long                   flags;

        spin_lock_irqsave(&chan->lock, flags);

        desc = chan->head;
        if (!desc) {
                chan->stats.empty_dequeue++;
                status = -ENOENT;
                goto unlock_ret;
        }
        desc_dma = desc_phys(pool, desc);

        status  = desc_read(desc, hw_mode);
        outlen  = status & 0x7ff;
        if (status & CPDMA_DESC_OWNER) {
                chan->stats.busy_dequeue++;
                status = -EBUSY;
                goto unlock_ret;
        }

        if (status & CPDMA_DESC_PASS_CRC)
                outlen -= CPDMA_DESC_CRC_LEN;

        status  = status & (CPDMA_DESC_EOQ | CPDMA_DESC_TD_COMPLETE |
                            CPDMA_DESC_PORT_MASK);

        chan->head = desc_from_phys(pool, desc_read(desc, hw_next));
        chan_write(chan, cp, desc_dma);
        chan->count--;
        chan->stats.good_dequeue++;

        if ((status & CPDMA_DESC_EOQ) && chan->head) {
                chan->stats.requeue++;
                chan_write(chan, hdp, desc_phys(pool, chan->head));
        }

        spin_unlock_irqrestore(&chan->lock, flags);
        if (unlikely(status & CPDMA_DESC_TD_COMPLETE))
                cb_status = -ENOSYS;
        else
                cb_status = status;

        __cpdma_chan_free(chan, desc, outlen, cb_status);
        return status;

unlock_ret:
        spin_unlock_irqrestore(&chan->lock, flags);
        return status;
}

int cpdma_chan_process(struct cpdma_chan *chan, int quota)
{
        int used = 0, ret = 0;

        if (chan->state != CPDMA_STATE_ACTIVE)
                return -EINVAL;

        while (used < quota) {
                ret = __cpdma_chan_process(chan);
                if (ret < 0)
                        break;
                used++;
        }
        return used;
}
EXPORT_SYMBOL_GPL(cpdma_chan_process);

int cpdma_chan_start(struct cpdma_chan *chan)
{
        struct cpdma_ctlr *ctlr = chan->ctlr;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&ctlr->lock, flags);
        ret = cpdma_chan_set_chan_shaper(chan);
        spin_unlock_irqrestore(&ctlr->lock, flags);
        if (ret)
                return ret;

        ret = cpdma_chan_on(chan);
        if (ret)
                return ret;

        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_chan_start);

int cpdma_chan_stop(struct cpdma_chan *chan)
{
        struct cpdma_ctlr       *ctlr = chan->ctlr;
        struct cpdma_desc_pool  *pool = ctlr->pool;
        unsigned long           flags;
        int                     ret;
        unsigned                timeout;

        spin_lock_irqsave(&chan->lock, flags);
        if (chan->state == CPDMA_STATE_TEARDOWN) {
                spin_unlock_irqrestore(&chan->lock, flags);
                return -EINVAL;
        }

        chan->state = CPDMA_STATE_TEARDOWN;
        dma_reg_write(ctlr, chan->int_clear, chan->mask);

        /* trigger teardown */
        dma_reg_write(ctlr, chan->td, chan_linear(chan));

        /* wait for teardown complete */
        timeout = 100 * 100; /* 100 ms */
        while (timeout) {
                u32 cp = chan_read(chan, cp);
                if ((cp & CPDMA_TEARDOWN_VALUE) == CPDMA_TEARDOWN_VALUE)
                        break;
                udelay(10);
                timeout--;
        }
        WARN_ON(!timeout);
        chan_write(chan, cp, CPDMA_TEARDOWN_VALUE);

        /* handle completed packets */
        spin_unlock_irqrestore(&chan->lock, flags);
        do {
                ret = __cpdma_chan_process(chan);
                if (ret < 0)
                        break;
        } while ((ret & CPDMA_DESC_TD_COMPLETE) == 0);
        spin_lock_irqsave(&chan->lock, flags);

        /* remaining packets haven't been tx/rx'ed, clean them up */
        while (chan->head) {
                struct cpdma_desc __iomem *desc = chan->head;
                dma_addr_t next_dma;

                next_dma = desc_read(desc, hw_next);
                chan->head = desc_from_phys(pool, next_dma);
                chan->count--;
                chan->stats.teardown_dequeue++;

                /* issue callback without locks held */
                spin_unlock_irqrestore(&chan->lock, flags);
                __cpdma_chan_free(chan, desc, 0, -ENOSYS);
                spin_lock_irqsave(&chan->lock, flags);
        }

        chan->state = CPDMA_STATE_IDLE;
        spin_unlock_irqrestore(&chan->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(cpdma_chan_stop);

int cpdma_chan_int_ctrl(struct cpdma_chan *chan, bool enable)
{
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);
        if (chan->state != CPDMA_STATE_ACTIVE) {
                spin_unlock_irqrestore(&chan->lock, flags);
                return -EINVAL;
        }

        dma_reg_write(chan->ctlr, enable ? chan->int_set : chan->int_clear,
                      chan->mask);
        spin_unlock_irqrestore(&chan->lock, flags);

        return 0;
}

int cpdma_control_get(struct cpdma_ctlr *ctlr, int control)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&ctlr->lock, flags);
        ret = _cpdma_control_get(ctlr, control);
        spin_unlock_irqrestore(&ctlr->lock, flags);

        return ret;
}

int cpdma_control_set(struct cpdma_ctlr *ctlr, int control, int value)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&ctlr->lock, flags);
        ret = _cpdma_control_set(ctlr, control, value);
        spin_unlock_irqrestore(&ctlr->lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(cpdma_control_set);

int cpdma_get_num_rx_descs(struct cpdma_ctlr *ctlr)
{
        return ctlr->num_rx_desc;
}
EXPORT_SYMBOL_GPL(cpdma_get_num_rx_descs);

int cpdma_get_num_tx_descs(struct cpdma_ctlr *ctlr)
{
        return ctlr->num_tx_desc;
}
EXPORT_SYMBOL_GPL(cpdma_get_num_tx_descs);

void cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc)
{
        ctlr->num_rx_desc = num_rx_desc;
        ctlr->num_tx_desc = ctlr->pool->num_desc - ctlr->num_rx_desc;
}
EXPORT_SYMBOL_GPL(cpdma_set_num_rx_descs);

MODULE_LICENSE("GPL");