/*
 * TI EDMA DMA engine driver
 *
 * Copyright 2012 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/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/bitmap.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/pm_runtime.h>

#include <linux/platform_data/edma.h>

#include "../dmaengine.h"
#include "../virt-dma.h"

/* Offsets matching "struct edmacc_param" */
#define PARM_OPT                0x00
#define PARM_SRC                0x04
#define PARM_A_B_CNT            0x08
#define PARM_DST                0x0c
#define PARM_SRC_DST_BIDX       0x10
#define PARM_LINK_BCNTRLD       0x14
#define PARM_SRC_DST_CIDX       0x18
#define PARM_CCNT               0x1c

#define PARM_SIZE               0x20

/* Offsets for EDMA CC global channel registers and their shadows */
#define SH_ER                   0x00    /* 64 bits */
#define SH_ECR                  0x08    /* 64 bits */
#define SH_ESR                  0x10    /* 64 bits */
#define SH_CER                  0x18    /* 64 bits */
#define SH_EER                  0x20    /* 64 bits */
#define SH_EECR                 0x28    /* 64 bits */
#define SH_EESR                 0x30    /* 64 bits */
#define SH_SER                  0x38    /* 64 bits */
#define SH_SECR                 0x40    /* 64 bits */
#define SH_IER                  0x50    /* 64 bits */
#define SH_IECR                 0x58    /* 64 bits */
#define SH_IESR                 0x60    /* 64 bits */
#define SH_IPR                  0x68    /* 64 bits */
#define SH_ICR                  0x70    /* 64 bits */
#define SH_IEVAL                0x78
#define SH_QER                  0x80
#define SH_QEER                 0x84
#define SH_QEECR                0x88
#define SH_QEESR                0x8c
#define SH_QSER                 0x90
#define SH_QSECR                0x94
#define SH_SIZE                 0x200

/* Offsets for EDMA CC global registers */
#define EDMA_REV                0x0000
#define EDMA_CCCFG              0x0004
#define EDMA_QCHMAP             0x0200  /* 8 registers */
#define EDMA_DMAQNUM            0x0240  /* 8 registers (4 on OMAP-L1xx) */
#define EDMA_QDMAQNUM           0x0260
#define EDMA_QUETCMAP           0x0280
#define EDMA_QUEPRI             0x0284
#define EDMA_EMR                0x0300  /* 64 bits */
#define EDMA_EMCR               0x0308  /* 64 bits */
#define EDMA_QEMR               0x0310
#define EDMA_QEMCR              0x0314
#define EDMA_CCERR              0x0318
#define EDMA_CCERRCLR           0x031c
#define EDMA_EEVAL              0x0320
#define EDMA_DRAE               0x0340  /* 4 x 64 bits*/
#define EDMA_QRAE               0x0380  /* 4 registers */
#define EDMA_QUEEVTENTRY        0x0400  /* 2 x 16 registers */
#define EDMA_QSTAT              0x0600  /* 2 registers */
#define EDMA_QWMTHRA            0x0620
#define EDMA_QWMTHRB            0x0624
#define EDMA_CCSTAT             0x0640

#define EDMA_M                  0x1000  /* global channel registers */
#define EDMA_ECR                0x1008
#define EDMA_ECRH               0x100C
#define EDMA_SHADOW0            0x2000  /* 4 shadow regions */
#define EDMA_PARM               0x4000  /* PaRAM entries */

#define PARM_OFFSET(param_no)   (EDMA_PARM + ((param_no) << 5))

#define EDMA_DCHMAP             0x0100  /* 64 registers */

/* CCCFG register */
#define GET_NUM_DMACH(x)        (x & 0x7) /* bits 0-2 */
#define GET_NUM_QDMACH(x)       ((x & 0x70) >> 4) /* bits 4-6 */
#define GET_NUM_PAENTRY(x)      ((x & 0x7000) >> 12) /* bits 12-14 */
#define GET_NUM_EVQUE(x)        ((x & 0x70000) >> 16) /* bits 16-18 */
#define GET_NUM_REGN(x)         ((x & 0x300000) >> 20) /* bits 20-21 */
#define CHMAP_EXIST             BIT(24)

/* CCSTAT register */
#define EDMA_CCSTAT_ACTV        BIT(4)

/*
 * Max of 20 segments per channel to conserve PaRAM slots
 * Also note that MAX_NR_SG should be atleast the no.of periods
 * that are required for ASoC, otherwise DMA prep calls will
 * fail. Today davinci-pcm is the only user of this driver and
 * requires atleast 17 slots, so we setup the default to 20.
 */
#define MAX_NR_SG               20
#define EDMA_MAX_SLOTS          MAX_NR_SG
#define EDMA_DESCRIPTORS        16

#define EDMA_CHANNEL_ANY                -1      /* for edma_alloc_channel() */
#define EDMA_SLOT_ANY                   -1      /* for edma_alloc_slot() */
#define EDMA_CONT_PARAMS_ANY             1001
#define EDMA_CONT_PARAMS_FIXED_EXACT     1002
#define EDMA_CONT_PARAMS_FIXED_NOT_EXACT 1003

/*
 * 64bit array registers are split into two 32bit registers:
 * reg0: channel/event 0-31
 * reg1: channel/event 32-63
 *
 * bit 5 in the channel number tells the array index (0/1)
 * bit 0-4 (0x1f) is the bit offset within the register
 */
#define EDMA_REG_ARRAY_INDEX(channel)   ((channel) >> 5)
#define EDMA_CHANNEL_BIT(channel)       (BIT((channel) & 0x1f))

/* PaRAM slots are laid out like this */
struct edmacc_param {
        u32 opt;
        u32 src;
        u32 a_b_cnt;
        u32 dst;
        u32 src_dst_bidx;
        u32 link_bcntrld;
        u32 src_dst_cidx;
        u32 ccnt;
} __packed;

/* fields in edmacc_param.opt */
#define SAM             BIT(0)
#define DAM             BIT(1)
#define SYNCDIM         BIT(2)
#define STATIC          BIT(3)
#define EDMA_FWID       (0x07 << 8)
#define TCCMODE         BIT(11)
#define EDMA_TCC(t)     ((t) << 12)
#define TCINTEN         BIT(20)
#define ITCINTEN        BIT(21)
#define TCCHEN          BIT(22)
#define ITCCHEN         BIT(23)

struct edma_pset {
        u32                             len;
        dma_addr_t                      addr;
        struct edmacc_param             param;
};

struct edma_desc {
        struct virt_dma_desc            vdesc;
        struct list_head                node;
        enum dma_transfer_direction     direction;
        int                             cyclic;
        bool                            polled;
        int                             absync;
        int                             pset_nr;
        struct edma_chan                *echan;
        int                             processed;

        /*
         * The following 4 elements are used for residue accounting.
         *
         * - processed_stat: the number of SG elements we have traversed
         * so far to cover accounting. This is updated directly to processed
         * during edma_callback and is always <= processed, because processed
         * refers to the number of pending transfer (programmed to EDMA
         * controller), where as processed_stat tracks number of transfers
         * accounted for so far.
         *
         * - residue: The amount of bytes we have left to transfer for this desc
         *
         * - residue_stat: The residue in bytes of data we have covered
         * so far for accounting. This is updated directly to residue
         * during callbacks to keep it current.
         *
         * - sg_len: Tracks the length of the current intermediate transfer,
         * this is required to update the residue during intermediate transfer
         * completion callback.
         */
        int                             processed_stat;
        u32                             sg_len;
        u32                             residue;
        u32                             residue_stat;

        struct edma_pset                pset[];
};

struct edma_cc;

struct edma_tc {
        struct device_node              *node;
        u16                             id;
};

struct edma_chan {
        struct virt_dma_chan            vchan;
        struct list_head                node;
        struct edma_desc                *edesc;
        struct edma_cc                  *ecc;
        struct edma_tc                  *tc;
        int                             ch_num;
        bool                            alloced;
        bool                            hw_triggered;
        int                             slot[EDMA_MAX_SLOTS];
        int                             missed;
        struct dma_slave_config         cfg;
};

struct edma_cc {
        struct device                   *dev;
        struct edma_soc_info            *info;
        void __iomem                    *base;
        int                             id;
        bool                            legacy_mode;

        /* eDMA3 resource information */
        unsigned                        num_channels;
        unsigned                        num_qchannels;
        unsigned                        num_region;
        unsigned                        num_slots;
        unsigned                        num_tc;
        bool                            chmap_exist;
        enum dma_event_q                default_queue;

        unsigned int                    ccint;
        unsigned int                    ccerrint;

        /*
         * The slot_inuse bit for each PaRAM slot is clear unless the slot is
         * in use by Linux or if it is allocated to be used by DSP.
         */
        unsigned long *slot_inuse;

        /*
         * For tracking reserved channels used by DSP.
         * If the bit is cleared, the channel is allocated to be used by DSP
         * and Linux must not touch it.
         */
        unsigned long *channels_mask;

        struct dma_device               dma_slave;
        struct dma_device               *dma_memcpy;
        struct edma_chan                *slave_chans;
        struct edma_tc                  *tc_list;
        int                             dummy_slot;
};

/* dummy param set used to (re)initialize parameter RAM slots */
static const struct edmacc_param dummy_paramset = {
        .link_bcntrld = 0xffff,
        .ccnt = 1,
};

#define EDMA_BINDING_LEGACY     0
#define EDMA_BINDING_TPCC       1
static const u32 edma_binding_type[] = {
        [EDMA_BINDING_LEGACY] = EDMA_BINDING_LEGACY,
        [EDMA_BINDING_TPCC] = EDMA_BINDING_TPCC,
};

static const struct of_device_id edma_of_ids[] = {
        {
                .compatible = "ti,edma3",
                .data = &edma_binding_type[EDMA_BINDING_LEGACY],
        },
        {
                .compatible = "ti,edma3-tpcc",
                .data = &edma_binding_type[EDMA_BINDING_TPCC],
        },
        {}
};
MODULE_DEVICE_TABLE(of, edma_of_ids);

static const struct of_device_id edma_tptc_of_ids[] = {
        { .compatible = "ti,edma3-tptc", },
        {}
};
MODULE_DEVICE_TABLE(of, edma_tptc_of_ids);

static inline unsigned int edma_read(struct edma_cc *ecc, int offset)
{
        return (unsigned int)__raw_readl(ecc->base + offset);
}

static inline void edma_write(struct edma_cc *ecc, int offset, int val)
{
        __raw_writel(val, ecc->base + offset);
}

static inline void edma_modify(struct edma_cc *ecc, int offset, unsigned and,
                               unsigned or)
{
        unsigned val = edma_read(ecc, offset);

        val &= and;
        val |= or;
        edma_write(ecc, offset, val);
}

static inline void edma_and(struct edma_cc *ecc, int offset, unsigned and)
{
        unsigned val = edma_read(ecc, offset);

        val &= and;
        edma_write(ecc, offset, val);
}

static inline void edma_or(struct edma_cc *ecc, int offset, unsigned or)
{
        unsigned val = edma_read(ecc, offset);

        val |= or;
        edma_write(ecc, offset, val);
}

static inline unsigned int edma_read_array(struct edma_cc *ecc, int offset,
                                           int i)
{
        return edma_read(ecc, offset + (i << 2));
}

static inline void edma_write_array(struct edma_cc *ecc, int offset, int i,
                                    unsigned val)
{
        edma_write(ecc, offset + (i << 2), val);
}

static inline void edma_modify_array(struct edma_cc *ecc, int offset, int i,
                                     unsigned and, unsigned or)
{
        edma_modify(ecc, offset + (i << 2), and, or);
}

static inline void edma_or_array(struct edma_cc *ecc, int offset, int i,
                                 unsigned or)
{
        edma_or(ecc, offset + (i << 2), or);
}

static inline void edma_or_array2(struct edma_cc *ecc, int offset, int i, int j,
                                  unsigned or)
{
        edma_or(ecc, offset + ((i * 2 + j) << 2), or);
}

static inline void edma_write_array2(struct edma_cc *ecc, int offset, int i,
                                     int j, unsigned val)
{
        edma_write(ecc, offset + ((i * 2 + j) << 2), val);
}

static inline unsigned int edma_shadow0_read(struct edma_cc *ecc, int offset)
{
        return edma_read(ecc, EDMA_SHADOW0 + offset);
}

static inline unsigned int edma_shadow0_read_array(struct edma_cc *ecc,
                                                   int offset, int i)
{
        return edma_read(ecc, EDMA_SHADOW0 + offset + (i << 2));
}

static inline void edma_shadow0_write(struct edma_cc *ecc, int offset,
                                      unsigned val)
{
        edma_write(ecc, EDMA_SHADOW0 + offset, val);
}

static inline void edma_shadow0_write_array(struct edma_cc *ecc, int offset,
                                            int i, unsigned val)
{
        edma_write(ecc, EDMA_SHADOW0 + offset + (i << 2), val);
}

static inline unsigned int edma_param_read(struct edma_cc *ecc, int offset,
                                           int param_no)
{
        return edma_read(ecc, EDMA_PARM + offset + (param_no << 5));
}

static inline void edma_param_write(struct edma_cc *ecc, int offset,
                                    int param_no, unsigned val)
{
        edma_write(ecc, EDMA_PARM + offset + (param_no << 5), val);
}

static inline void edma_param_modify(struct edma_cc *ecc, int offset,
                                     int param_no, unsigned and, unsigned or)
{
        edma_modify(ecc, EDMA_PARM + offset + (param_no << 5), and, or);
}

static inline void edma_param_and(struct edma_cc *ecc, int offset, int param_no,
                                  unsigned and)
{
        edma_and(ecc, EDMA_PARM + offset + (param_no << 5), and);
}

static inline void edma_param_or(struct edma_cc *ecc, int offset, int param_no,
                                 unsigned or)
{
        edma_or(ecc, EDMA_PARM + offset + (param_no << 5), or);
}

static void edma_assign_priority_to_queue(struct edma_cc *ecc, int queue_no,
                                          int priority)
{
        int bit = queue_no * 4;

        edma_modify(ecc, EDMA_QUEPRI, ~(0x7 << bit), ((priority & 0x7) << bit));
}

static void edma_set_chmap(struct edma_chan *echan, int slot)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);

        if (ecc->chmap_exist) {
                slot = EDMA_CHAN_SLOT(slot);
                edma_write_array(ecc, EDMA_DCHMAP, channel, (slot << 5));
        }
}

static void edma_setup_interrupt(struct edma_chan *echan, bool enable)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);
        int idx = EDMA_REG_ARRAY_INDEX(channel);
        int ch_bit = EDMA_CHANNEL_BIT(channel);

        if (enable) {
                edma_shadow0_write_array(ecc, SH_ICR, idx, ch_bit);
                edma_shadow0_write_array(ecc, SH_IESR, idx, ch_bit);
        } else {
                edma_shadow0_write_array(ecc, SH_IECR, idx, ch_bit);
        }
}

/*
 * paRAM slot management functions
 */
static void edma_write_slot(struct edma_cc *ecc, unsigned slot,
                            const struct edmacc_param *param)
{
        slot = EDMA_CHAN_SLOT(slot);
        if (slot >= ecc->num_slots)
                return;
        memcpy_toio(ecc->base + PARM_OFFSET(slot), param, PARM_SIZE);
}

static int edma_read_slot(struct edma_cc *ecc, unsigned slot,
                           struct edmacc_param *param)
{
        slot = EDMA_CHAN_SLOT(slot);
        if (slot >= ecc->num_slots)
                return -EINVAL;
        memcpy_fromio(param, ecc->base + PARM_OFFSET(slot), PARM_SIZE);

        return 0;
}

/**
 * edma_alloc_slot - allocate DMA parameter RAM
 * @ecc: pointer to edma_cc struct
 * @slot: specific slot to allocate; negative for "any unused slot"
 *
 * This allocates a parameter RAM slot, initializing it to hold a
 * dummy transfer.  Slots allocated using this routine have not been
 * mapped to a hardware DMA channel, and will normally be used by
 * linking to them from a slot associated with a DMA channel.
 *
 * Normal use is to pass EDMA_SLOT_ANY as the @slot, but specific
 * slots may be allocated on behalf of DSP firmware.
 *
 * Returns the number of the slot, else negative errno.
 */
static int edma_alloc_slot(struct edma_cc *ecc, int slot)
{
        if (slot >= 0) {
                slot = EDMA_CHAN_SLOT(slot);
                /* Requesting entry paRAM slot for a HW triggered channel. */
                if (ecc->chmap_exist && slot < ecc->num_channels)
                        slot = EDMA_SLOT_ANY;
        }

        if (slot < 0) {
                if (ecc->chmap_exist)
                        slot = 0;
                else
                        slot = ecc->num_channels;
                for (;;) {
                        slot = find_next_zero_bit(ecc->slot_inuse,
                                                  ecc->num_slots,
                                                  slot);
                        if (slot == ecc->num_slots)
                                return -ENOMEM;
                        if (!test_and_set_bit(slot, ecc->slot_inuse))
                                break;
                }
        } else if (slot >= ecc->num_slots) {
                return -EINVAL;
        } else if (test_and_set_bit(slot, ecc->slot_inuse)) {
                return -EBUSY;
        }

        edma_write_slot(ecc, slot, &dummy_paramset);

        return EDMA_CTLR_CHAN(ecc->id, slot);
}

static void edma_free_slot(struct edma_cc *ecc, unsigned slot)
{
        slot = EDMA_CHAN_SLOT(slot);
        if (slot >= ecc->num_slots)
                return;

        edma_write_slot(ecc, slot, &dummy_paramset);
        clear_bit(slot, ecc->slot_inuse);
}

/**
 * edma_link - link one parameter RAM slot to another
 * @ecc: pointer to edma_cc struct
 * @from: parameter RAM slot originating the link
 * @to: parameter RAM slot which is the link target
 *
 * The originating slot should not be part of any active DMA transfer.
 */
static void edma_link(struct edma_cc *ecc, unsigned from, unsigned to)
{
        if (unlikely(EDMA_CTLR(from) != EDMA_CTLR(to)))
                dev_warn(ecc->dev, "Ignoring eDMA instance for linking\n");

        from = EDMA_CHAN_SLOT(from);
        to = EDMA_CHAN_SLOT(to);
        if (from >= ecc->num_slots || to >= ecc->num_slots)
                return;

        edma_param_modify(ecc, PARM_LINK_BCNTRLD, from, 0xffff0000,
                          PARM_OFFSET(to));
}

/**
 * edma_get_position - returns the current transfer point
 * @ecc: pointer to edma_cc struct
 * @slot: parameter RAM slot being examined
 * @dst:  true selects the dest position, false the source
 *
 * Returns the position of the current active slot
 */
static dma_addr_t edma_get_position(struct edma_cc *ecc, unsigned slot,
                                    bool dst)
{
        u32 offs;

        slot = EDMA_CHAN_SLOT(slot);
        offs = PARM_OFFSET(slot);
        offs += dst ? PARM_DST : PARM_SRC;

        return edma_read(ecc, offs);
}

/*
 * Channels with event associations will be triggered by their hardware
 * events, and channels without such associations will be triggered by
 * software.  (At this writing there is no interface for using software
 * triggers except with channels that don't support hardware triggers.)
 */
static void edma_start(struct edma_chan *echan)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);
        int idx = EDMA_REG_ARRAY_INDEX(channel);
        int ch_bit = EDMA_CHANNEL_BIT(channel);

        if (!echan->hw_triggered) {
                /* EDMA channels without event association */
                dev_dbg(ecc->dev, "ESR%d %08x\n", idx,
                        edma_shadow0_read_array(ecc, SH_ESR, idx));
                edma_shadow0_write_array(ecc, SH_ESR, idx, ch_bit);
        } else {
                /* EDMA channel with event association */
                dev_dbg(ecc->dev, "ER%d %08x\n", idx,
                        edma_shadow0_read_array(ecc, SH_ER, idx));
                /* Clear any pending event or error */
                edma_write_array(ecc, EDMA_ECR, idx, ch_bit);
                edma_write_array(ecc, EDMA_EMCR, idx, ch_bit);
                /* Clear any SER */
                edma_shadow0_write_array(ecc, SH_SECR, idx, ch_bit);
                edma_shadow0_write_array(ecc, SH_EESR, idx, ch_bit);
                dev_dbg(ecc->dev, "EER%d %08x\n", idx,
                        edma_shadow0_read_array(ecc, SH_EER, idx));
        }
}

static void edma_stop(struct edma_chan *echan)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);
        int idx = EDMA_REG_ARRAY_INDEX(channel);
        int ch_bit = EDMA_CHANNEL_BIT(channel);

        edma_shadow0_write_array(ecc, SH_EECR, idx, ch_bit);
        edma_shadow0_write_array(ecc, SH_ECR, idx, ch_bit);
        edma_shadow0_write_array(ecc, SH_SECR, idx, ch_bit);
        edma_write_array(ecc, EDMA_EMCR, idx, ch_bit);

        /* clear possibly pending completion interrupt */
        edma_shadow0_write_array(ecc, SH_ICR, idx, ch_bit);

        dev_dbg(ecc->dev, "EER%d %08x\n", idx,
                edma_shadow0_read_array(ecc, SH_EER, idx));

        /* REVISIT:  consider guarding against inappropriate event
         * chaining by overwriting with dummy_paramset.
         */
}

/*
 * Temporarily disable EDMA hardware events on the specified channel,
 * preventing them from triggering new transfers
 */
static void edma_pause(struct edma_chan *echan)
{
        int channel = EDMA_CHAN_SLOT(echan->ch_num);

        edma_shadow0_write_array(echan->ecc, SH_EECR,
                                 EDMA_REG_ARRAY_INDEX(channel),
                                 EDMA_CHANNEL_BIT(channel));
}

/* Re-enable EDMA hardware events on the specified channel.  */
static void edma_resume(struct edma_chan *echan)
{
        int channel = EDMA_CHAN_SLOT(echan->ch_num);

        edma_shadow0_write_array(echan->ecc, SH_EESR,
                                 EDMA_REG_ARRAY_INDEX(channel),
                                 EDMA_CHANNEL_BIT(channel));
}

static void edma_trigger_channel(struct edma_chan *echan)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);
        int idx = EDMA_REG_ARRAY_INDEX(channel);
        int ch_bit = EDMA_CHANNEL_BIT(channel);

        edma_shadow0_write_array(ecc, SH_ESR, idx, ch_bit);

        dev_dbg(ecc->dev, "ESR%d %08x\n", idx,
                edma_shadow0_read_array(ecc, SH_ESR, idx));
}

static void edma_clean_channel(struct edma_chan *echan)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);
        int idx = EDMA_REG_ARRAY_INDEX(channel);
        int ch_bit = EDMA_CHANNEL_BIT(channel);

        dev_dbg(ecc->dev, "EMR%d %08x\n", idx,
                edma_read_array(ecc, EDMA_EMR, idx));
        edma_shadow0_write_array(ecc, SH_ECR, idx, ch_bit);
        /* Clear the corresponding EMR bits */
        edma_write_array(ecc, EDMA_EMCR, idx, ch_bit);
        /* Clear any SER */
        edma_shadow0_write_array(ecc, SH_SECR, idx, ch_bit);
        edma_write(ecc, EDMA_CCERRCLR, BIT(16) | BIT(1) | BIT(0));
}

/* Move channel to a specific event queue */
static void edma_assign_channel_eventq(struct edma_chan *echan,
                                       enum dma_event_q eventq_no)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);
        int bit = (channel & 0x7) * 4;

        /* default to low priority queue */
        if (eventq_no == EVENTQ_DEFAULT)
                eventq_no = ecc->default_queue;
        if (eventq_no >= ecc->num_tc)
                return;

        eventq_no &= 7;
        edma_modify_array(ecc, EDMA_DMAQNUM, (channel >> 3), ~(0x7 << bit),
                          eventq_no << bit);
}

static int edma_alloc_channel(struct edma_chan *echan,
                              enum dma_event_q eventq_no)
{
        struct edma_cc *ecc = echan->ecc;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);

        if (!test_bit(echan->ch_num, ecc->channels_mask)) {
                dev_err(ecc->dev, "Channel%d is reserved, can not be used!\n",
                        echan->ch_num);
                return -EINVAL;
        }

        /* ensure access through shadow region 0 */
        edma_or_array2(ecc, EDMA_DRAE, 0, EDMA_REG_ARRAY_INDEX(channel),
                       EDMA_CHANNEL_BIT(channel));

        /* ensure no events are pending */
        edma_stop(echan);

        edma_setup_interrupt(echan, true);

        edma_assign_channel_eventq(echan, eventq_no);

        return 0;
}

static void edma_free_channel(struct edma_chan *echan)
{
        /* ensure no events are pending */
        edma_stop(echan);
        /* REVISIT should probably take out of shadow region 0 */
        edma_setup_interrupt(echan, false);
}

static inline struct edma_cc *to_edma_cc(struct dma_device *d)
{
        return container_of(d, struct edma_cc, dma_slave);
}

static inline struct edma_chan *to_edma_chan(struct dma_chan *c)
{
        return container_of(c, struct edma_chan, vchan.chan);
}

static inline struct edma_desc *to_edma_desc(struct dma_async_tx_descriptor *tx)
{
        return container_of(tx, struct edma_desc, vdesc.tx);
}

static void edma_desc_free(struct virt_dma_desc *vdesc)
{
        kfree(container_of(vdesc, struct edma_desc, vdesc));
}

/* Dispatch a queued descriptor to the controller (caller holds lock) */
static void edma_execute(struct edma_chan *echan)
{
        struct edma_cc *ecc = echan->ecc;
        struct virt_dma_desc *vdesc;
        struct edma_desc *edesc;
        struct device *dev = echan->vchan.chan.device->dev;
        int i, j, left, nslots;

        if (!echan->edesc) {
                /* Setup is needed for the first transfer */
                vdesc = vchan_next_desc(&echan->vchan);
                if (!vdesc)
                        return;
                list_del(&vdesc->node);
                echan->edesc = to_edma_desc(&vdesc->tx);
        }

        edesc = echan->edesc;

        /* Find out how many left */
        left = edesc->pset_nr - edesc->processed;
        nslots = min(MAX_NR_SG, left);
        edesc->sg_len = 0;

        /* Write descriptor PaRAM set(s) */
        for (i = 0; i < nslots; i++) {
                j = i + edesc->processed;
                edma_write_slot(ecc, echan->slot[i], &edesc->pset[j].param);
                edesc->sg_len += edesc->pset[j].len;
                dev_vdbg(dev,
                         "\n pset[%d]:\n"
                         "  chnum\t%d\n"
                         "  slot\t%d\n"
                         "  opt\t%08x\n"
                         "  src\t%08x\n"
                         "  dst\t%08x\n"
                         "  abcnt\t%08x\n"
                         "  ccnt\t%08x\n"
                         "  bidx\t%08x\n"
                         "  cidx\t%08x\n"
                         "  lkrld\t%08x\n",
                         j, echan->ch_num, echan->slot[i],
                         edesc->pset[j].param.opt,
                         edesc->pset[j].param.src,
                         edesc->pset[j].param.dst,
                         edesc->pset[j].param.a_b_cnt,
                         edesc->pset[j].param.ccnt,
                         edesc->pset[j].param.src_dst_bidx,
                         edesc->pset[j].param.src_dst_cidx,
                         edesc->pset[j].param.link_bcntrld);
                /* Link to the previous slot if not the last set */
                if (i != (nslots - 1))
                        edma_link(ecc, echan->slot[i], echan->slot[i + 1]);
        }

        edesc->processed += nslots;

        /*
         * If this is either the last set in a set of SG-list transactions
         * then setup a link to the dummy slot, this results in all future
         * events being absorbed and that's OK because we're done
         */
        if (edesc->processed == edesc->pset_nr) {
                if (edesc->cyclic)
                        edma_link(ecc, echan->slot[nslots - 1], echan->slot[1]);
                else
                        edma_link(ecc, echan->slot[nslots - 1],
                                  echan->ecc->dummy_slot);
        }

        if (echan->missed) {
                /*
                 * This happens due to setup times between intermediate
                 * transfers in long SG lists which have to be broken up into
                 * transfers of MAX_NR_SG
                 */
                dev_dbg(dev, "missed event on channel %d\n", echan->ch_num);
                edma_clean_channel(echan);
                edma_stop(echan);
                edma_start(echan);
                edma_trigger_channel(echan);
                echan->missed = 0;
        } else if (edesc->processed <= MAX_NR_SG) {
                dev_dbg(dev, "first transfer starting on channel %d\n",
                        echan->ch_num);
                edma_start(echan);
        } else {
                dev_dbg(dev, "chan: %d: completed %d elements, resuming\n",
                        echan->ch_num, edesc->processed);
                edma_resume(echan);
        }
}

static int edma_terminate_all(struct dma_chan *chan)
{
        struct edma_chan *echan = to_edma_chan(chan);
        unsigned long flags;
        LIST_HEAD(head);

        spin_lock_irqsave(&echan->vchan.lock, flags);

        /*
         * Stop DMA activity: we assume the callback will not be called
         * after edma_dma() returns (even if it does, it will see
         * echan->edesc is NULL and exit.)
         */
        if (echan->edesc) {
                edma_stop(echan);
                /* Move the cyclic channel back to default queue */
                if (!echan->tc && echan->edesc->cyclic)
                        edma_assign_channel_eventq(echan, EVENTQ_DEFAULT);

                vchan_terminate_vdesc(&echan->edesc->vdesc);
                echan->edesc = NULL;
        }

        vchan_get_all_descriptors(&echan->vchan, &head);
        spin_unlock_irqrestore(&echan->vchan.lock, flags);
        vchan_dma_desc_free_list(&echan->vchan, &head);

        return 0;
}

static void edma_synchronize(struct dma_chan *chan)
{
        struct edma_chan *echan = to_edma_chan(chan);

        vchan_synchronize(&echan->vchan);
}

static int edma_slave_config(struct dma_chan *chan,
        struct dma_slave_config *cfg)
{
        struct edma_chan *echan = to_edma_chan(chan);

        if (cfg->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
            cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
                return -EINVAL;

        if (cfg->src_maxburst > chan->device->max_burst ||
            cfg->dst_maxburst > chan->device->max_burst)
                return -EINVAL;

        memcpy(&echan->cfg, cfg, sizeof(echan->cfg));

        return 0;
}

static int edma_dma_pause(struct dma_chan *chan)
{
        struct edma_chan *echan = to_edma_chan(chan);

        if (!echan->edesc)
                return -EINVAL;

        edma_pause(echan);
        return 0;
}

static int edma_dma_resume(struct dma_chan *chan)
{
        struct edma_chan *echan = to_edma_chan(chan);

        edma_resume(echan);
        return 0;
}

/*
 * A PaRAM set configuration abstraction used by other modes
 * @chan: Channel who's PaRAM set we're configuring
 * @pset: PaRAM set to initialize and setup.
 * @src_addr: Source address of the DMA
 * @dst_addr: Destination address of the DMA
 * @burst: In units of dev_width, how much to send
 * @dev_width: How much is the dev_width
 * @dma_length: Total length of the DMA transfer
 * @direction: Direction of the transfer
 */
static int edma_config_pset(struct dma_chan *chan, struct edma_pset *epset,
                            dma_addr_t src_addr, dma_addr_t dst_addr, u32 burst,
                            unsigned int acnt, unsigned int dma_length,
                            enum dma_transfer_direction direction)
{
        struct edma_chan *echan = to_edma_chan(chan);
        struct device *dev = chan->device->dev;
        struct edmacc_param *param = &epset->param;
        int bcnt, ccnt, cidx;
        int src_bidx, dst_bidx, src_cidx, dst_cidx;
        int absync;

        /* src/dst_maxburst == 0 is the same case as src/dst_maxburst == 1 */
        if (!burst)
                burst = 1;
        /*
         * If the maxburst is equal to the fifo width, use
         * A-synced transfers. This allows for large contiguous
         * buffer transfers using only one PaRAM set.
         */
        if (burst == 1) {
                /*
                 * For the A-sync case, bcnt and ccnt are the remainder
                 * and quotient respectively of the division of:
                 * (dma_length / acnt) by (SZ_64K -1). This is so
                 * that in case bcnt over flows, we have ccnt to use.
                 * Note: In A-sync tranfer only, bcntrld is used, but it
                 * only applies for sg_dma_len(sg) >= SZ_64K.
                 * In this case, the best way adopted is- bccnt for the
                 * first frame will be the remainder below. Then for
                 * every successive frame, bcnt will be SZ_64K-1. This
                 * is assured as bcntrld = 0xffff in end of function.
                 */
                absync = false;
                ccnt = dma_length / acnt / (SZ_64K - 1);
                bcnt = dma_length / acnt - ccnt * (SZ_64K - 1);
                /*
                 * If bcnt is non-zero, we have a remainder and hence an
                 * extra frame to transfer, so increment ccnt.
                 */
                if (bcnt)
                        ccnt++;
                else
                        bcnt = SZ_64K - 1;
                cidx = acnt;
        } else {
                /*
                 * If maxburst is greater than the fifo address_width,

                 * use AB-synced transfers where A count is the fifo
                 * address_width and B count is the maxburst. In this
                 * case, we are limited to transfers of C count frames
                 * of (address_width * maxburst) where C count is limited
                 * to SZ_64K-1. This places an upper bound on the length
                 * of an SG segment that can be handled.
                 */
                absync = true;
                bcnt = burst;
                ccnt = dma_length / (acnt * bcnt);
                if (ccnt > (SZ_64K - 1)) {
                        dev_err(dev, "Exceeded max SG segment size\n");
                        return -EINVAL;
                }
                cidx = acnt * bcnt;
        }

        epset->len = dma_length;

        if (direction == DMA_MEM_TO_DEV) {
                src_bidx = acnt;
                src_cidx = cidx;
                dst_bidx = 0;
                dst_cidx = 0;
                epset->addr = src_addr;
        } else if (direction == DMA_DEV_TO_MEM)  {
                src_bidx = 0;
                src_cidx = 0;
                dst_bidx = acnt;
                dst_cidx = cidx;
                epset->addr = dst_addr;
        } else if (direction == DMA_MEM_TO_MEM)  {
                src_bidx = acnt;
                src_cidx = cidx;
                dst_bidx = acnt;
                dst_cidx = cidx;
                epset->addr = src_addr;
        } else {
                dev_err(dev, "%s: direction not implemented yet\n", __func__);
                return -EINVAL;
        }

        param->opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
        /* Configure A or AB synchronized transfers */
        if (absync)
                param->opt |= SYNCDIM;

        param->src = src_addr;
        param->dst = dst_addr;

        param->src_dst_bidx = (dst_bidx << 16) | src_bidx;
        param->src_dst_cidx = (dst_cidx << 16) | src_cidx;

        param->a_b_cnt = bcnt << 16 | acnt;
        param->ccnt = ccnt;
        /*
         * Only time when (bcntrld) auto reload is required is for
         * A-sync case, and in this case, a requirement of reload value
         * of SZ_64K-1 only is assured. 'link' is initially set to NULL
         * and then later will be populated by edma_execute.
         */
        param->link_bcntrld = 0xffffffff;
        return absync;
}

static struct dma_async_tx_descriptor *edma_prep_slave_sg(
        struct dma_chan *chan, struct scatterlist *sgl,
        unsigned int sg_len, enum dma_transfer_direction direction,
        unsigned long tx_flags, void *context)
{
        struct edma_chan *echan = to_edma_chan(chan);
        struct device *dev = chan->device->dev;
        struct edma_desc *edesc;
        dma_addr_t src_addr = 0, dst_addr = 0;
        enum dma_slave_buswidth dev_width;
        u32 burst;
        struct scatterlist *sg;
        int i, nslots, ret;

        if (unlikely(!echan || !sgl || !sg_len))
                return NULL;

        if (direction == DMA_DEV_TO_MEM) {
                src_addr = echan->cfg.src_addr;
                dev_width = echan->cfg.src_addr_width;
                burst = echan->cfg.src_maxburst;
        } else if (direction == DMA_MEM_TO_DEV) {
                dst_addr = echan->cfg.dst_addr;
                dev_width = echan->cfg.dst_addr_width;
                burst = echan->cfg.dst_maxburst;
        } else {
                dev_err(dev, "%s: bad direction: %d\n", __func__, direction);
                return NULL;
        }

        if (dev_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
                dev_err(dev, "%s: Undefined slave buswidth\n", __func__);
                return NULL;
        }

        edesc = kzalloc(struct_size(edesc, pset, sg_len), GFP_ATOMIC);
        if (!edesc)
                return NULL;

        edesc->pset_nr = sg_len;
        edesc->residue = 0;
        edesc->direction = direction;
        edesc->echan = echan;

        /* Allocate a PaRAM slot, if needed */
        nslots = min_t(unsigned, MAX_NR_SG, sg_len);

        for (i = 0; i < nslots; i++) {
                if (echan->slot[i] < 0) {
                        echan->slot[i] =
                                edma_alloc_slot(echan->ecc, EDMA_SLOT_ANY);
                        if (echan->slot[i] < 0) {
                                kfree(edesc);
                                dev_err(dev, "%s: Failed to allocate slot\n",
                                        __func__);
                                return NULL;
                        }
                }
        }

        /* Configure PaRAM sets for each SG */
        for_each_sg(sgl, sg, sg_len, i) {
                /* Get address for each SG */
                if (direction == DMA_DEV_TO_MEM)
                        dst_addr = sg_dma_address(sg);
                else
                        src_addr = sg_dma_address(sg);

                ret = edma_config_pset(chan, &edesc->pset[i], src_addr,
                                       dst_addr, burst, dev_width,
                                       sg_dma_len(sg), direction);
                if (ret < 0) {
                        kfree(edesc);
                        return NULL;
                }

                edesc->absync = ret;
                edesc->residue += sg_dma_len(sg);

                if (i == sg_len - 1)
                        /* Enable completion interrupt */
                        edesc->pset[i].param.opt |= TCINTEN;
                else if (!((i+1) % MAX_NR_SG))
                        /*
                         * Enable early completion interrupt for the
                         * intermediateset. In this case the driver will be
                         * notified when the paRAM set is submitted to TC. This
                         * will allow more time to set up the next set of slots.
                         */
                        edesc->pset[i].param.opt |= (TCINTEN | TCCMODE);
        }
        edesc->residue_stat = edesc->residue;

        return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
}

static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
        struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
        size_t len, unsigned long tx_flags)
{
        int ret, nslots;
        struct edma_desc *edesc;
        struct device *dev = chan->device->dev;
        struct edma_chan *echan = to_edma_chan(chan);
        unsigned int width, pset_len, array_size;

        if (unlikely(!echan || !len))
                return NULL;

        /* Align the array size (acnt block) with the transfer properties */
        switch (__ffs((src | dest | len))) {
        case 0:
                array_size = SZ_32K - 1;
                break;
        case 1:
                array_size = SZ_32K - 2;
                break;
        default:
                array_size = SZ_32K - 4;
                break;
        }

        if (len < SZ_64K) {
                /*
                 * Transfer size less than 64K can be handled with one paRAM
                 * slot and with one burst.
                 * ACNT = length
                 */
                width = len;
                pset_len = len;
                nslots = 1;
        } else {
                /*
                 * Transfer size bigger than 64K will be handled with maximum of
                 * two paRAM slots.
                 * slot1: (full_length / 32767) times 32767 bytes bursts.
                 *        ACNT = 32767, length1: (full_length / 32767) * 32767
                 * slot2: the remaining amount of data after slot1.
                 *        ACNT = full_length - length1, length2 = ACNT
                 *
                 * When the full_length is multibple of 32767 one slot can be
                 * used to complete the transfer.
                 */
                width = array_size;
                pset_len = rounddown(len, width);
                /* One slot is enough for lengths multiple of (SZ_32K -1) */
                if (unlikely(pset_len == len))
                        nslots = 1;
                else
                        nslots = 2;
        }

        edesc = kzalloc(struct_size(edesc, pset, nslots), GFP_ATOMIC);
        if (!edesc)
                return NULL;

        edesc->pset_nr = nslots;
        edesc->residue = edesc->residue_stat = len;
        edesc->direction = DMA_MEM_TO_MEM;
        edesc->echan = echan;

        ret = edma_config_pset(chan, &edesc->pset[0], src, dest, 1,
                               width, pset_len, DMA_MEM_TO_MEM);
        if (ret < 0) {
                kfree(edesc);
                return NULL;
        }

        edesc->absync = ret;

        edesc->pset[0].param.opt |= ITCCHEN;
        if (nslots == 1) {
                /* Enable transfer complete interrupt if requested */
                if (tx_flags & DMA_PREP_INTERRUPT)
                        edesc->pset[0].param.opt |= TCINTEN;
        } else {
                /* Enable transfer complete chaining for the first slot */
                edesc->pset[0].param.opt |= TCCHEN;

                if (echan->slot[1] < 0) {
                        echan->slot[1] = edma_alloc_slot(echan->ecc,
                                                         EDMA_SLOT_ANY);
                        if (echan->slot[1] < 0) {
                                kfree(edesc);
                                dev_err(dev, "%s: Failed to allocate slot\n",
                                        __func__);
                                return NULL;
                        }
                }
                dest += pset_len;
                src += pset_len;
                pset_len = width = len % array_size;

                ret = edma_config_pset(chan, &edesc->pset[1], src, dest, 1,
                                       width, pset_len, DMA_MEM_TO_MEM);
                if (ret < 0) {
                        kfree(edesc);
                        return NULL;
                }

                edesc->pset[1].param.opt |= ITCCHEN;
                /* Enable transfer complete interrupt if requested */
                if (tx_flags & DMA_PREP_INTERRUPT)
                        edesc->pset[1].param.opt |= TCINTEN;
        }

        if (!(tx_flags & DMA_PREP_INTERRUPT))
                edesc->polled = true;

        return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
}

static struct dma_async_tx_descriptor *
edma_prep_dma_interleaved(struct dma_chan *chan,
                          struct dma_interleaved_template *xt,
                          unsigned long tx_flags)
{
        struct device *dev = chan->device->dev;
        struct edma_chan *echan = to_edma_chan(chan);
        struct edmacc_param *param;
        struct edma_desc *edesc;
        size_t src_icg, dst_icg;
        int src_bidx, dst_bidx;

        /* Slave mode is not supported */
        if (is_slave_direction(xt->dir))
                return NULL;

        if (xt->frame_size != 1 || xt->numf == 0)
                return NULL;

        if (xt->sgl[0].size > SZ_64K || xt->numf > SZ_64K)
                return NULL;

        src_icg = dmaengine_get_src_icg(xt, &xt->sgl[0]);
        if (src_icg) {
                src_bidx = src_icg + xt->sgl[0].size;
        } else if (xt->src_inc) {
                src_bidx = xt->sgl[0].size;
        } else {
                dev_err(dev, "%s: SRC constant addressing is not supported\n",
                        __func__);
                return NULL;
        }

        dst_icg = dmaengine_get_dst_icg(xt, &xt->sgl[0]);
        if (dst_icg) {
                dst_bidx = dst_icg + xt->sgl[0].size;
        } else if (xt->dst_inc) {
                dst_bidx = xt->sgl[0].size;
        } else {
                dev_err(dev, "%s: DST constant addressing is not supported\n",
                        __func__);
                return NULL;
        }

        if (src_bidx > SZ_64K || dst_bidx > SZ_64K)
                return NULL;

        edesc = kzalloc(struct_size(edesc, pset, 1), GFP_ATOMIC);
        if (!edesc)
                return NULL;

        edesc->direction = DMA_MEM_TO_MEM;
        edesc->echan = echan;
        edesc->pset_nr = 1;

        param = &edesc->pset[0].param;

        param->src = xt->src_start;
        param->dst = xt->dst_start;
        param->a_b_cnt = xt->numf << 16 | xt->sgl[0].size;
        param->ccnt = 1;
        param->src_dst_bidx = (dst_bidx << 16) | src_bidx;
        param->src_dst_cidx = 0;

        param->opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
        param->opt |= ITCCHEN;
        /* Enable transfer complete interrupt if requested */
        if (tx_flags & DMA_PREP_INTERRUPT)
                param->opt |= TCINTEN;
        else
                edesc->polled = true;

        return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
}

static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
        struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
        size_t period_len, enum dma_transfer_direction direction,
        unsigned long tx_flags)
{
        struct edma_chan *echan = to_edma_chan(chan);
        struct device *dev = chan->device->dev;
        struct edma_desc *edesc;
        dma_addr_t src_addr, dst_addr;
        enum dma_slave_buswidth dev_width;
        bool use_intermediate = false;
        u32 burst;
        int i, ret, nslots;

        if (unlikely(!echan || !buf_len || !period_len))
                return NULL;

        if (direction == DMA_DEV_TO_MEM) {
                src_addr = echan->cfg.src_addr;
                dst_addr = buf_addr;
                dev_width = echan->cfg.src_addr_width;
                burst = echan->cfg.src_maxburst;
        } else if (direction == DMA_MEM_TO_DEV) {
                src_addr = buf_addr;
                dst_addr = echan->cfg.dst_addr;
                dev_width = echan->cfg.dst_addr_width;
                burst = echan->cfg.dst_maxburst;
        } else {
                dev_err(dev, "%s: bad direction: %d\n", __func__, direction);
                return NULL;
        }

        if (dev_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
                dev_err(dev, "%s: Undefined slave buswidth\n", __func__);
                return NULL;
        }

        if (unlikely(buf_len % period_len)) {
                dev_err(dev, "Period should be multiple of Buffer length\n");
                return NULL;
        }

        nslots = (buf_len / period_len) + 1;

        /*
         * Cyclic DMA users such as audio cannot tolerate delays introduced
         * by cases where the number of periods is more than the maximum
         * number of SGs the EDMA driver can handle at a time. For DMA types
         * such as Slave SGs, such delays are tolerable and synchronized,
         * but the synchronization is difficult to achieve with Cyclic and
         * cannot be guaranteed, so we error out early.
         */
        if (nslots > MAX_NR_SG) {
                /*
                 * If the burst and period sizes are the same, we can put
                 * the full buffer into a single period and activate
                 * intermediate interrupts. This will produce interrupts
                 * after each burst, which is also after each desired period.
                 */
                if (burst == period_len) {
                        period_len = buf_len;
                        nslots = 2;
                        use_intermediate = true;
                } else {
                        return NULL;
                }
        }

        edesc = kzalloc(struct_size(edesc, pset, nslots), GFP_ATOMIC);
        if (!edesc)
                return NULL;

        edesc->cyclic = 1;
        edesc->pset_nr = nslots;
        edesc->residue = edesc->residue_stat = buf_len;
        edesc->direction = direction;
        edesc->echan = echan;

        dev_dbg(dev, "%s: channel=%d nslots=%d period_len=%zu buf_len=%zu\n",
                __func__, echan->ch_num, nslots, period_len, buf_len);

        for (i = 0; i < nslots; i++) {
                /* Allocate a PaRAM slot, if needed */
                if (echan->slot[i] < 0) {
                        echan->slot[i] =
                                edma_alloc_slot(echan->ecc, EDMA_SLOT_ANY);
                        if (echan->slot[i] < 0) {
                                kfree(edesc);
                                dev_err(dev, "%s: Failed to allocate slot\n",
                                        __func__);
                                return NULL;
                        }
                }

                if (i == nslots - 1) {
                        memcpy(&edesc->pset[i], &edesc->pset[0],
                               sizeof(edesc->pset[0]));
                        break;
                }

                ret = edma_config_pset(chan, &edesc->pset[i], src_addr,
                                       dst_addr, burst, dev_width, period_len,
                                       direction);
                if (ret < 0) {
                        kfree(edesc);
                        return NULL;
                }

                if (direction == DMA_DEV_TO_MEM)
                        dst_addr += period_len;
                else
                        src_addr += period_len;

                dev_vdbg(dev, "%s: Configure period %d of buf:\n", __func__, i);
                dev_vdbg(dev,
                        "\n pset[%d]:\n"
                        "  chnum\t%d\n"
                        "  slot\t%d\n"
                        "  opt\t%08x\n"
                        "  src\t%08x\n"
                        "  dst\t%08x\n"
                        "  abcnt\t%08x\n"
                        "  ccnt\t%08x\n"
                        "  bidx\t%08x\n"
                        "  cidx\t%08x\n"
                        "  lkrld\t%08x\n",
                        i, echan->ch_num, echan->slot[i],
                        edesc->pset[i].param.opt,
                        edesc->pset[i].param.src,
                        edesc->pset[i].param.dst,
                        edesc->pset[i].param.a_b_cnt,
                        edesc->pset[i].param.ccnt,
                        edesc->pset[i].param.src_dst_bidx,
                        edesc->pset[i].param.src_dst_cidx,
                        edesc->pset[i].param.link_bcntrld);

                edesc->absync = ret;

                /*
                 * Enable period interrupt only if it is requested
                 */
                if (tx_flags & DMA_PREP_INTERRUPT) {
                        edesc->pset[i].param.opt |= TCINTEN;

                        /* Also enable intermediate interrupts if necessary */
                        if (use_intermediate)
                                edesc->pset[i].param.opt |= ITCINTEN;
                }
        }

        /* Place the cyclic channel to highest priority queue */
        if (!echan->tc)
                edma_assign_channel_eventq(echan, EVENTQ_0);

        return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
}

static void edma_completion_handler(struct edma_chan *echan)
{
        struct device *dev = echan->vchan.chan.device->dev;
        struct edma_desc *edesc;

        spin_lock(&echan->vchan.lock);
        edesc = echan->edesc;
        if (edesc) {
                if (edesc->cyclic) {
                        vchan_cyclic_callback(&edesc->vdesc);
                        spin_unlock(&echan->vchan.lock);
                        return;
                } else if (edesc->processed == edesc->pset_nr) {
                        edesc->residue = 0;
                        edma_stop(echan);
                        vchan_cookie_complete(&edesc->vdesc);
                        echan->edesc = NULL;

                        dev_dbg(dev, "Transfer completed on channel %d\n",
                                echan->ch_num);
                } else {
                        dev_dbg(dev, "Sub transfer completed on channel %d\n",
                                echan->ch_num);

                        edma_pause(echan);

                        /* Update statistics for tx_status */
                        edesc->residue -= edesc->sg_len;
                        edesc->residue_stat = edesc->residue;
                        edesc->processed_stat = edesc->processed;
                }
                edma_execute(echan);
        }

        spin_unlock(&echan->vchan.lock);
}

/* eDMA interrupt handler */
static irqreturn_t dma_irq_handler(int irq, void *data)
{
        struct edma_cc *ecc = data;
        int ctlr;
        u32 sh_ier;
        u32 sh_ipr;
        u32 bank;

        ctlr = ecc->id;
        if (ctlr < 0)
                return IRQ_NONE;

        dev_vdbg(ecc->dev, "dma_irq_handler\n");

        sh_ipr = edma_shadow0_read_array(ecc, SH_IPR, 0);
        if (!sh_ipr) {
                sh_ipr = edma_shadow0_read_array(ecc, SH_IPR, 1);
                if (!sh_ipr)
                        return IRQ_NONE;
                sh_ier = edma_shadow0_read_array(ecc, SH_IER, 1);
                bank = 1;
        } else {
                sh_ier = edma_shadow0_read_array(ecc, SH_IER, 0);
                bank = 0;
        }

        do {
                u32 slot;
                u32 channel;

                slot = __ffs(sh_ipr);
                sh_ipr &= ~(BIT(slot));

                if (sh_ier & BIT(slot)) {
                        channel = (bank << 5) | slot;
                        /* Clear the corresponding IPR bits */
                        edma_shadow0_write_array(ecc, SH_ICR, bank, BIT(slot));
                        edma_completion_handler(&ecc->slave_chans[channel]);
                }
        } while (sh_ipr);

        edma_shadow0_write(ecc, SH_IEVAL, 1);
        return IRQ_HANDLED;
}

static void edma_error_handler(struct edma_chan *echan)
{
        struct edma_cc *ecc = echan->ecc;
        struct device *dev = echan->vchan.chan.device->dev;
        struct edmacc_param p;
        int err;

        if (!echan->edesc)
                return;

        spin_lock(&echan->vchan.lock);

        err = edma_read_slot(ecc, echan->slot[0], &p);

        /*
         * Issue later based on missed flag which will be sure
         * to happen as:
         * (1) we finished transmitting an intermediate slot and
         *     edma_execute is coming up.
         * (2) or we finished current transfer and issue will
         *     call edma_execute.
         *
         * Important note: issuing can be dangerous here and
         * lead to some nasty recursion when we are in a NULL
         * slot. So we avoid doing so and set the missed flag.
         */
        if (err || (p.a_b_cnt == 0 && p.ccnt == 0)) {
                dev_dbg(dev, "Error on null slot, setting miss\n");
                echan->missed = 1;
        } else {
                /*
                 * The slot is already programmed but the event got
                 * missed, so its safe to issue it here.
                 */
                dev_dbg(dev, "Missed event, TRIGGERING\n");
                edma_clean_channel(echan);
                edma_stop(echan);
                edma_start(echan);
                edma_trigger_channel(echan);
        }
        spin_unlock(&echan->vchan.lock);
}

static inline bool edma_error_pending(struct edma_cc *ecc)
{
        if (edma_read_array(ecc, EDMA_EMR, 0) ||
            edma_read_array(ecc, EDMA_EMR, 1) ||
            edma_read(ecc, EDMA_QEMR) || edma_read(ecc, EDMA_CCERR))
                return true;

        return false;
}

/* eDMA error interrupt handler */
static irqreturn_t dma_ccerr_handler(int irq, void *data)
{
        struct edma_cc *ecc = data;
        int i, j;
        int ctlr;
        unsigned int cnt = 0;
        unsigned int val;

        ctlr = ecc->id;
        if (ctlr < 0)
                return IRQ_NONE;

        dev_vdbg(ecc->dev, "dma_ccerr_handler\n");

        if (!edma_error_pending(ecc)) {
                /*
                 * The registers indicate no pending error event but the irq
                 * handler has been called.
                 * Ask eDMA to re-evaluate the error registers.
                 */
                dev_err(ecc->dev, "%s: Error interrupt without error event!\n",
                        __func__);
                edma_write(ecc, EDMA_EEVAL, 1);
                return IRQ_NONE;
        }

        while (1) {
                /* Event missed register(s) */
                for (j = 0; j < 2; j++) {
                        unsigned long emr;

                        val = edma_read_array(ecc, EDMA_EMR, j);
                        if (!val)
                                continue;

                        dev_dbg(ecc->dev, "EMR%d 0x%08x\n", j, val);
                        emr = val;
                        for (i = find_next_bit(&emr, 32, 0); i < 32;
                             i = find_next_bit(&emr, 32, i + 1)) {
                                int k = (j << 5) + i;

                                /* Clear the corresponding EMR bits */
                                edma_write_array(ecc, EDMA_EMCR, j, BIT(i));
                                /* Clear any SER */
                                edma_shadow0_write_array(ecc, SH_SECR, j,
                                                         BIT(i));
                                edma_error_handler(&ecc->slave_chans[k]);
                        }
                }

                val = edma_read(ecc, EDMA_QEMR);
                if (val) {
                        dev_dbg(ecc->dev, "QEMR 0x%02x\n", val);
                        /* Not reported, just clear the interrupt reason. */
                        edma_write(ecc, EDMA_QEMCR, val);
                        edma_shadow0_write(ecc, SH_QSECR, val);
                }

                val = edma_read(ecc, EDMA_CCERR);
                if (val) {
                        dev_warn(ecc->dev, "CCERR 0x%08x\n", val);
                        /* Not reported, just clear the interrupt reason. */
                        edma_write(ecc, EDMA_CCERRCLR, val);
                }

                if (!edma_error_pending(ecc))
                        break;
                cnt++;
                if (cnt > 10)
                        break;
        }
        edma_write(ecc, EDMA_EEVAL, 1);
        return IRQ_HANDLED;
}

/* Alloc channel resources */
static int edma_alloc_chan_resources(struct dma_chan *chan)
{
        struct edma_chan *echan = to_edma_chan(chan);
        struct edma_cc *ecc = echan->ecc;
        struct device *dev = ecc->dev;
        enum dma_event_q eventq_no = EVENTQ_DEFAULT;
        int ret;

        if (echan->tc) {
                eventq_no = echan->tc->id;
        } else if (ecc->tc_list) {
                /* memcpy channel */
                echan->tc = &ecc->tc_list[ecc->info->default_queue];
                eventq_no = echan->tc->id;
        }

        ret = edma_alloc_channel(echan, eventq_no);
        if (ret)
                return ret;

        echan->slot[0] = edma_alloc_slot(ecc, echan->ch_num);
        if (echan->slot[0] < 0) {
                dev_err(dev, "Entry slot allocation failed for channel %u\n",
                        EDMA_CHAN_SLOT(echan->ch_num));
                ret = echan->slot[0];
                goto err_slot;
        }

        /* Set up channel -> slot mapping for the entry slot */
        edma_set_chmap(echan, echan->slot[0]);
        echan->alloced = true;

        dev_dbg(dev, "Got eDMA channel %d for virt channel %d (%s trigger)\n",
                EDMA_CHAN_SLOT(echan->ch_num), chan->chan_id,
                echan->hw_triggered ? "HW" : "SW");

        return 0;

err_slot:
        edma_free_channel(echan);
        return ret;
}

/* Free channel resources */
static void edma_free_chan_resources(struct dma_chan *chan)
{
        struct edma_chan *echan = to_edma_chan(chan);
        struct device *dev = echan->ecc->dev;
        int i;

        /* Terminate transfers */
        edma_stop(echan);

        vchan_free_chan_resources(&echan->vchan);

        /* Free EDMA PaRAM slots */
        for (i = 0; i < EDMA_MAX_SLOTS; i++) {
                if (echan->slot[i] >= 0) {
                        edma_free_slot(echan->ecc, echan->slot[i]);
                        echan->slot[i] = -1;
                }
        }

        /* Set entry slot to the dummy slot */
        edma_set_chmap(echan, echan->ecc->dummy_slot);

        /* Free EDMA channel */
        if (echan->alloced) {
                edma_free_channel(echan);
                echan->alloced = false;
        }

        echan->tc = NULL;
        echan->hw_triggered = false;

        dev_dbg(dev, "Free eDMA channel %d for virt channel %d\n",
                EDMA_CHAN_SLOT(echan->ch_num), chan->chan_id);
}

/* Send pending descriptor to hardware */
static void edma_issue_pending(struct dma_chan *chan)
{
        struct edma_chan *echan = to_edma_chan(chan);
        unsigned long flags;

        spin_lock_irqsave(&echan->vchan.lock, flags);
        if (vchan_issue_pending(&echan->vchan) && !echan->edesc)
                edma_execute(echan);
        spin_unlock_irqrestore(&echan->vchan.lock, flags);
}

/*
 * This limit exists to avoid a possible infinite loop when waiting for proof
 * that a particular transfer is completed. This limit can be hit if there
 * are large bursts to/from slow devices or the CPU is never able to catch
 * the DMA hardware idle. On an AM335x transfering 48 bytes from the UART
 * RX-FIFO, as many as 55 loops have been seen.
 */
#define EDMA_MAX_TR_WAIT_LOOPS 1000

static u32 edma_residue(struct edma_desc *edesc)
{
        bool dst = edesc->direction == DMA_DEV_TO_MEM;
        int loop_count = EDMA_MAX_TR_WAIT_LOOPS;
        struct edma_chan *echan = edesc->echan;
        struct edma_pset *pset = edesc->pset;
        dma_addr_t done, pos, pos_old;
        int channel = EDMA_CHAN_SLOT(echan->ch_num);
        int idx = EDMA_REG_ARRAY_INDEX(channel);
        int ch_bit = EDMA_CHANNEL_BIT(channel);
        int event_reg;
        int i;

        /*
         * We always read the dst/src position from the first RamPar
         * pset. That's the one which is active now.
         */
        pos = edma_get_position(echan->ecc, echan->slot[0], dst);

        /*
         * "pos" may represent a transfer request that is still being
         * processed by the EDMACC or EDMATC. We will busy wait until
         * any one of the situations occurs:
         *   1. while and event is pending for the channel
         *   2. a position updated
         *   3. we hit the loop limit
         */
        if (is_slave_direction(edesc->direction))
                event_reg = SH_ER;
        else
                event_reg = SH_ESR;

        pos_old = pos;
        while (edma_shadow0_read_array(echan->ecc, event_reg, idx) & ch_bit) {
                pos = edma_get_position(echan->ecc, echan->slot[0], dst);
                if (pos != pos_old)
                        break;

                if (!--loop_count) {
                        dev_dbg_ratelimited(echan->vchan.chan.device->dev,
                                "%s: timeout waiting for PaRAM update\n",
                                __func__);
                        break;
                }

                cpu_relax();
        }

        /*
         * Cyclic is simple. Just subtract pset[0].addr from pos.
         *
         * We never update edesc->residue in the cyclic case, so we
         * can tell the remaining room to the end of the circular
         * buffer.
         */
        if (edesc->cyclic) {
                done = pos - pset->addr;
                edesc->residue_stat = edesc->residue - done;
                return edesc->residue_stat;
        }

        /*
         * If the position is 0, then EDMA loaded the closing dummy slot, the
         * transfer is completed
         */
        if (!pos)
                return 0;
        /*
         * For SG operation we catch up with the last processed
         * status.
         */
        pset += edesc->processed_stat;

        for (i = edesc->processed_stat; i < edesc->processed; i++, pset++) {
                /*
                 * If we are inside this pset address range, we know
                 * this is the active one. Get the current delta and
                 * stop walking the psets.
                 */
                if (pos >= pset->addr && pos < pset->addr + pset->len)
                        return edesc->residue_stat - (pos - pset->addr);

                /* Otherwise mark it done and update residue_stat. */
                edesc->processed_stat++;
                edesc->residue_stat -= pset->len;
        }
        return edesc->residue_stat;
}

/* Check request completion status */
static enum dma_status edma_tx_status(struct dma_chan *chan,
                                      dma_cookie_t cookie,
                                      struct dma_tx_state *txstate)
{
        struct edma_chan *echan = to_edma_chan(chan);
        struct dma_tx_state txstate_tmp;
        enum dma_status ret;
        unsigned long flags;

        ret = dma_cookie_status(chan, cookie, txstate);

        if (ret == DMA_COMPLETE)
                return ret;

        /* Provide a dummy dma_tx_state for completion checking */
        if (!txstate)
                txstate = &txstate_tmp;

        spin_lock_irqsave(&echan->vchan.lock, flags);
        if (echan->edesc && echan->edesc->vdesc.tx.cookie == cookie) {
                txstate->residue = edma_residue(echan->edesc);
        } else {
                struct virt_dma_desc *vdesc = vchan_find_desc(&echan->vchan,
                                                              cookie);

                if (vdesc)
                        txstate->residue = to_edma_desc(&vdesc->tx)->residue;
                else
                        txstate->residue = 0;
        }

        /*
         * Mark the cookie completed if the residue is 0 for non cyclic
         * transfers
         */
        if (ret != DMA_COMPLETE && !txstate->residue &&
            echan->edesc && echan->edesc->polled &&
            echan->edesc->vdesc.tx.cookie == cookie) {
                edma_stop(echan);
                vchan_cookie_complete(&echan->edesc->vdesc);
                echan->edesc = NULL;
                edma_execute(echan);
                ret = DMA_COMPLETE;
        }

        spin_unlock_irqrestore(&echan->vchan.lock, flags);

        return ret;
}

static bool edma_is_memcpy_channel(int ch_num, s32 *memcpy_channels)
{
        if (!memcpy_channels)
                return false;
        while (*memcpy_channels != -1) {
                if (*memcpy_channels == ch_num)
                        return true;
                memcpy_channels++;
        }
        return false;
}

#define EDMA_DMA_BUSWIDTHS      (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
                                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
                                 BIT(DMA_SLAVE_BUSWIDTH_3_BYTES) | \
                                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))

static void edma_dma_init(struct edma_cc *ecc, bool legacy_mode)
{
        struct dma_device *s_ddev = &ecc->dma_slave;
        struct dma_device *m_ddev = NULL;
        s32 *memcpy_channels = ecc->info->memcpy_channels;
        int i, j;

        dma_cap_zero(s_ddev->cap_mask);
        dma_cap_set(DMA_SLAVE, s_ddev->cap_mask);
        dma_cap_set(DMA_CYCLIC, s_ddev->cap_mask);
        if (ecc->legacy_mode && !memcpy_channels) {
                dev_warn(ecc->dev,
                         "Legacy memcpy is enabled, things might not work\n");

                dma_cap_set(DMA_MEMCPY, s_ddev->cap_mask);
                dma_cap_set(DMA_INTERLEAVE, s_ddev->cap_mask);
                s_ddev->device_prep_dma_memcpy = edma_prep_dma_memcpy;
                s_ddev->device_prep_interleaved_dma = edma_prep_dma_interleaved;
                s_ddev->directions = BIT(DMA_MEM_TO_MEM);
        }

        s_ddev->device_prep_slave_sg = edma_prep_slave_sg;
        s_ddev->device_prep_dma_cyclic = edma_prep_dma_cyclic;
        s_ddev->device_alloc_chan_resources = edma_alloc_chan_resources;
        s_ddev->device_free_chan_resources = edma_free_chan_resources;
        s_ddev->device_issue_pending = edma_issue_pending;
        s_ddev->device_tx_status = edma_tx_status;
        s_ddev->device_config = edma_slave_config;
        s_ddev->device_pause = edma_dma_pause;
        s_ddev->device_resume = edma_dma_resume;
        s_ddev->device_terminate_all = edma_terminate_all;
        s_ddev->device_synchronize = edma_synchronize;

        s_ddev->src_addr_widths = EDMA_DMA_BUSWIDTHS;
        s_ddev->dst_addr_widths = EDMA_DMA_BUSWIDTHS;
        s_ddev->directions |= (BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV));
        s_ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
        s_ddev->max_burst = SZ_32K - 1; /* CIDX: 16bit signed */

        s_ddev->dev = ecc->dev;
        INIT_LIST_HEAD(&s_ddev->channels);

        if (memcpy_channels) {
                m_ddev = devm_kzalloc(ecc->dev, sizeof(*m_ddev), GFP_KERNEL);
                if (!m_ddev) {
                        dev_warn(ecc->dev, "memcpy is disabled due to OoM\n");
                        memcpy_channels = NULL;
                        goto ch_setup;
                }
                ecc->dma_memcpy = m_ddev;

                dma_cap_zero(m_ddev->cap_mask);
                dma_cap_set(DMA_MEMCPY, m_ddev->cap_mask);
                dma_cap_set(DMA_INTERLEAVE, m_ddev->cap_mask);

                m_ddev->device_prep_dma_memcpy = edma_prep_dma_memcpy;
                m_ddev->device_prep_interleaved_dma = edma_prep_dma_interleaved;
                m_ddev->device_alloc_chan_resources = edma_alloc_chan_resources;
                m_ddev->device_free_chan_resources = edma_free_chan_resources;
                m_ddev->device_issue_pending = edma_issue_pending;
                m_ddev->device_tx_status = edma_tx_status;
                m_ddev->device_config = edma_slave_config;
                m_ddev->device_pause = edma_dma_pause;
                m_ddev->device_resume = edma_dma_resume;
                m_ddev->device_terminate_all = edma_terminate_all;
                m_ddev->device_synchronize = edma_synchronize;

                m_ddev->src_addr_widths = EDMA_DMA_BUSWIDTHS;
                m_ddev->dst_addr_widths = EDMA_DMA_BUSWIDTHS;
                m_ddev->directions = BIT(DMA_MEM_TO_MEM);
                m_ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;

                m_ddev->dev = ecc->dev;
                INIT_LIST_HEAD(&m_ddev->channels);
        } else if (!ecc->legacy_mode) {
                dev_info(ecc->dev, "memcpy is disabled\n");
        }

ch_setup:
        for (i = 0; i < ecc->num_channels; i++) {
                struct edma_chan *echan = &ecc->slave_chans[i];
                echan->ch_num = EDMA_CTLR_CHAN(ecc->id, i);
                echan->ecc = ecc;
                echan->vchan.desc_free = edma_desc_free;

                if (m_ddev && edma_is_memcpy_channel(i, memcpy_channels))
                        vchan_init(&echan->vchan, m_ddev);
                else
                        vchan_init(&echan->vchan, s_ddev);

                INIT_LIST_HEAD(&echan->node);
                for (j = 0; j < EDMA_MAX_SLOTS; j++)
                        echan->slot[j] = -1;
        }
}

static int edma_setup_from_hw(struct device *dev, struct edma_soc_info *pdata,
                              struct edma_cc *ecc)
{
        int i;
        u32 value, cccfg;
        s8 (*queue_priority_map)[2];

        /* Decode the eDMA3 configuration from CCCFG register */
        cccfg = edma_read(ecc, EDMA_CCCFG);

        value = GET_NUM_REGN(cccfg);
        ecc->num_region = BIT(value);

        value = GET_NUM_DMACH(cccfg);
        ecc->num_channels = BIT(value + 1);

        value = GET_NUM_QDMACH(cccfg);
        ecc->num_qchannels = value * 2;

        value = GET_NUM_PAENTRY(cccfg);
        ecc->num_slots = BIT(value + 4);

        value = GET_NUM_EVQUE(cccfg);
        ecc->num_tc = value + 1;

        ecc->chmap_exist = (cccfg & CHMAP_EXIST) ? true : false;

        dev_dbg(dev, "eDMA3 CC HW configuration (cccfg: 0x%08x):\n", cccfg);
        dev_dbg(dev, "num_region: %u\n", ecc->num_region);
        dev_dbg(dev, "num_channels: %u\n", ecc->num_channels);
        dev_dbg(dev, "num_qchannels: %u\n", ecc->num_qchannels);
        dev_dbg(dev, "num_slots: %u\n", ecc->num_slots);
        dev_dbg(dev, "num_tc: %u\n", ecc->num_tc);
        dev_dbg(dev, "chmap_exist: %s\n", ecc->chmap_exist ? "yes" : "no");

        /* Nothing need to be done if queue priority is provided */
        if (pdata->queue_priority_mapping)
                return 0;

        /*
         * Configure TC/queue priority as follows:
         * Q0 - priority 0
         * Q1 - priority 1
         * Q2 - priority 2
         * ...
         * The meaning of priority numbers: 0 highest priority, 7 lowest
         * priority. So Q0 is the highest priority queue and the last queue has
         * the lowest priority.
         */
        queue_priority_map = devm_kcalloc(dev, ecc->num_tc + 1, sizeof(s8),
                                          GFP_KERNEL);
        if (!queue_priority_map)
                return -ENOMEM;

        for (i = 0; i < ecc->num_tc; i++) {
                queue_priority_map[i][0] = i;
                queue_priority_map[i][1] = i;
        }
        queue_priority_map[i][0] = -1;
        queue_priority_map[i][1] = -1;

        pdata->queue_priority_mapping = queue_priority_map;
        /* Default queue has the lowest priority */
        pdata->default_queue = i - 1;

        return 0;
}

#if IS_ENABLED(CONFIG_OF)
static int edma_xbar_event_map(struct device *dev, struct edma_soc_info *pdata,
                               size_t sz)
{
        const char pname[] = "ti,edma-xbar-event-map";
        struct resource res;
        void __iomem *xbar;
        s16 (*xbar_chans)[2];
        size_t nelm = sz / sizeof(s16);
        u32 shift, offset, mux;
        int ret, i;

        xbar_chans = devm_kcalloc(dev, nelm + 2, sizeof(s16), GFP_KERNEL);
        if (!xbar_chans)
                return -ENOMEM;

        ret = of_address_to_resource(dev->of_node, 1, &res);
        if (ret)
                return -ENOMEM;

        xbar = devm_ioremap(dev, res.start, resource_size(&res));
        if (!xbar)
                return -ENOMEM;

        ret = of_property_read_u16_array(dev->of_node, pname, (u16 *)xbar_chans,
                                         nelm);
        if (ret)
                return -EIO;

        /* Invalidate last entry for the other user of this mess */
        nelm >>= 1;
        xbar_chans[nelm][0] = -1;
        xbar_chans[nelm][1] = -1;

        for (i = 0; i < nelm; i++) {
                shift = (xbar_chans[i][1] & 0x03) << 3;
                offset = xbar_chans[i][1] & 0xfffffffc;
                mux = readl(xbar + offset);
                mux &= ~(0xff << shift);
                mux |= xbar_chans[i][0] << shift;
                writel(mux, (xbar + offset));
        }

        pdata->xbar_chans = (const s16 (*)[2]) xbar_chans;
        return 0;
}

static struct edma_soc_info *edma_setup_info_from_dt(struct device *dev,
                                                     bool legacy_mode)
{
        struct edma_soc_info *info;
        struct property *prop;
        int sz, ret;

        info = devm_kzalloc(dev, sizeof(struct edma_soc_info), GFP_KERNEL);
        if (!info)
                return ERR_PTR(-ENOMEM);

        if (legacy_mode) {
                prop = of_find_property(dev->of_node, "ti,edma-xbar-event-map",
                                        &sz);
                if (prop) {
                        ret = edma_xbar_event_map(dev, info, sz);
                        if (ret)
                                return ERR_PTR(ret);
                }
                return info;
        }

        /* Get the list of channels allocated to be used for memcpy */
        prop = of_find_property(dev->of_node, "ti,edma-memcpy-channels", &sz);
        if (prop) {
                const char pname[] = "ti,edma-memcpy-channels";
                size_t nelm = sz / sizeof(s32);
                s32 *memcpy_ch;

                memcpy_ch = devm_kcalloc(dev, nelm + 1, sizeof(s32),
                                         GFP_KERNEL);
                if (!memcpy_ch)
                        return ERR_PTR(-ENOMEM);

                ret = of_property_read_u32_array(dev->of_node, pname,
                                                 (u32 *)memcpy_ch, nelm);
                if (ret)
                        return ERR_PTR(ret);

                memcpy_ch[nelm] = -1;
                info->memcpy_channels = memcpy_ch;
        }

        prop = of_find_property(dev->of_node, "ti,edma-reserved-slot-ranges",
                                &sz);
        if (prop) {
                const char pname[] = "ti,edma-reserved-slot-ranges";
                u32 (*tmp)[2];
                s16 (*rsv_slots)[2];
                size_t nelm = sz / sizeof(*tmp);
                struct edma_rsv_info *rsv_info;
                int i;

                if (!nelm)
                        return info;

                tmp = kcalloc(nelm, sizeof(*tmp), GFP_KERNEL);
                if (!tmp)
                        return ERR_PTR(-ENOMEM);

                rsv_info = devm_kzalloc(dev, sizeof(*rsv_info), GFP_KERNEL);
                if (!rsv_info) {
                        kfree(tmp);
                        return ERR_PTR(-ENOMEM);
                }

                rsv_slots = devm_kcalloc(dev, nelm + 1, sizeof(*rsv_slots),
                                         GFP_KERNEL);
                if (!rsv_slots) {
                        kfree(tmp);
                        return ERR_PTR(-ENOMEM);
                }

                ret = of_property_read_u32_array(dev->of_node, pname,
                                                 (u32 *)tmp, nelm * 2);
                if (ret) {
                        kfree(tmp);
                        return ERR_PTR(ret);
                }

                for (i = 0; i < nelm; i++) {
                        rsv_slots[i][0] = tmp[i][0];
                        rsv_slots[i][1] = tmp[i][1];
                }
                rsv_slots[nelm][0] = -1;
                rsv_slots[nelm][1] = -1;

                info->rsv = rsv_info;
                info->rsv->rsv_slots = (const s16 (*)[2])rsv_slots;

                kfree(tmp);
        }

        return info;
}

static struct dma_chan *of_edma_xlate(struct of_phandle_args *dma_spec,
                                      struct of_dma *ofdma)
{
        struct edma_cc *ecc = ofdma->of_dma_data;
        struct dma_chan *chan = NULL;
        struct edma_chan *echan;
        int i;

        if (!ecc || dma_spec->args_count < 1)
                return NULL;

        for (i = 0; i < ecc->num_channels; i++) {
                echan = &ecc->slave_chans[i];
                if (echan->ch_num == dma_spec->args[0]) {
                        chan = &echan->vchan.chan;
                        break;
                }
        }

        if (!chan)
                return NULL;

        if (echan->ecc->legacy_mode && dma_spec->args_count == 1)
                goto out;

        if (!echan->ecc->legacy_mode && dma_spec->args_count == 2 &&
            dma_spec->args[1] < echan->ecc->num_tc) {
                echan->tc = &echan->ecc->tc_list[dma_spec->args[1]];
                goto out;
        }

        return NULL;
out:
        /* The channel is going to be used as HW synchronized */
        echan->hw_triggered = true;
        return dma_get_slave_channel(chan);
}
#else
static struct edma_soc_info *edma_setup_info_from_dt(struct device *dev,
                                                     bool legacy_mode)
{
        return ERR_PTR(-EINVAL);
}

static struct dma_chan *of_edma_xlate(struct of_phandle_args *dma_spec,
                                      struct of_dma *ofdma)
{
        return NULL;
}
#endif

static bool edma_filter_fn(struct dma_chan *chan, void *param);

static int edma_probe(struct platform_device *pdev)
{
        struct edma_soc_info    *info = pdev->dev.platform_data;
        s8                      (*queue_priority_mapping)[2];
        const s16               (*reserved)[2];
        int                     i, irq;
        char                    *irq_name;
        struct resource         *mem;
        struct device_node      *node = pdev->dev.of_node;
        struct device           *dev = &pdev->dev;
        struct edma_cc          *ecc;
        bool                    legacy_mode = true;
        int ret;

        if (node) {
                const struct of_device_id *match;

                match = of_match_node(edma_of_ids, node);
                if (match && (*(u32 *)match->data) == EDMA_BINDING_TPCC)
                        legacy_mode = false;

                info = edma_setup_info_from_dt(dev, legacy_mode);
                if (IS_ERR(info)) {
                        dev_err(dev, "failed to get DT data\n");
                        return PTR_ERR(info);
                }
        }

        if (!info)
                return -ENODEV;

        ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        ecc = devm_kzalloc(dev, sizeof(*ecc), GFP_KERNEL);
        if (!ecc)
                return -ENOMEM;

        ecc->dev = dev;
        ecc->id = pdev->id;
        ecc->legacy_mode = legacy_mode;
        /* When booting with DT the pdev->id is -1 */
        if (ecc->id < 0)
                ecc->id = 0;

        mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "edma3_cc");
        if (!mem) {
                dev_dbg(dev, "mem resource not found, using index 0\n");
                mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
                if (!mem) {
                        dev_err(dev, "no mem resource?\n");
                        return -ENODEV;
                }
        }
        ecc->base = devm_ioremap_resource(dev, mem);
        if (IS_ERR(ecc->base))
                return PTR_ERR(ecc->base);

        platform_set_drvdata(pdev, ecc);

        pm_runtime_enable(dev);
        ret = pm_runtime_get_sync(dev);
        if (ret < 0) {
                dev_err(dev, "pm_runtime_get_sync() failed\n");
                pm_runtime_disable(dev);
                return ret;
        }

        /* Get eDMA3 configuration from IP */
        ret = edma_setup_from_hw(dev, info, ecc);
        if (ret)
                goto err_disable_pm;

        /* Allocate memory based on the information we got from the IP */
        ecc->slave_chans = devm_kcalloc(dev, ecc->num_channels,
                                        sizeof(*ecc->slave_chans), GFP_KERNEL);

        ecc->slot_inuse = devm_kcalloc(dev, BITS_TO_LONGS(ecc->num_slots),
                                       sizeof(unsigned long), GFP_KERNEL);

        ecc->channels_mask = devm_kcalloc(dev,
                                           BITS_TO_LONGS(ecc->num_channels),
                                           sizeof(unsigned long), GFP_KERNEL);
        if (!ecc->slave_chans || !ecc->slot_inuse || !ecc->channels_mask) {
                ret = -ENOMEM;
                goto err_disable_pm;
        }

        /* Mark all channels available initially */
        bitmap_fill(ecc->channels_mask, ecc->num_channels);

        ecc->default_queue = info->default_queue;

        if (info->rsv) {
                /* Set the reserved slots in inuse list */
                reserved = info->rsv->rsv_slots;
                if (reserved) {
                        for (i = 0; reserved[i][0] != -1; i++)
                                bitmap_set(ecc->slot_inuse, reserved[i][0],
                                           reserved[i][1]);
                }

                /* Clear channels not usable for Linux */
                reserved = info->rsv->rsv_chans;
                if (reserved) {
                        for (i = 0; reserved[i][0] != -1; i++)
                                bitmap_clear(ecc->channels_mask, reserved[i][0],
                                             reserved[i][1]);
                }
        }

        for (i = 0; i < ecc->num_slots; i++) {
                /* Reset only unused - not reserved - paRAM slots */
                if (!test_bit(i, ecc->slot_inuse))
                        edma_write_slot(ecc, i, &dummy_paramset);
        }

        irq = platform_get_irq_byname(pdev, "edma3_ccint");
        if (irq < 0 && node)
                irq = irq_of_parse_and_map(node, 0);

        if (irq >= 0) {
                irq_name = devm_kasprintf(dev, GFP_KERNEL, "%s_ccint",
                                          dev_name(dev));
                ret = devm_request_irq(dev, irq, dma_irq_handler, 0, irq_name,
                                       ecc);
                if (ret) {
                        dev_err(dev, "CCINT (%d) failed --> %d\n", irq, ret);
                        goto err_disable_pm;
                }
                ecc->ccint = irq;
        }

        irq = platform_get_irq_byname(pdev, "edma3_ccerrint");
        if (irq < 0 && node)
                irq = irq_of_parse_and_map(node, 2);

        if (irq >= 0) {
                irq_name = devm_kasprintf(dev, GFP_KERNEL, "%s_ccerrint",
                                          dev_name(dev));
                ret = devm_request_irq(dev, irq, dma_ccerr_handler, 0, irq_name,
                                       ecc);
                if (ret) {
                        dev_err(dev, "CCERRINT (%d) failed --> %d\n", irq, ret);
                        goto err_disable_pm;
                }
                ecc->ccerrint = irq;
        }

        ecc->dummy_slot = edma_alloc_slot(ecc, EDMA_SLOT_ANY);
        if (ecc->dummy_slot < 0) {
                dev_err(dev, "Can't allocate PaRAM dummy slot\n");
                ret = ecc->dummy_slot;
                goto err_disable_pm;
        }

        queue_priority_mapping = info->queue_priority_mapping;

        if (!ecc->legacy_mode) {
                int lowest_priority = 0;
                unsigned int array_max;
                struct of_phandle_args tc_args;

                ecc->tc_list = devm_kcalloc(dev, ecc->num_tc,
                                            sizeof(*ecc->tc_list), GFP_KERNEL);
                if (!ecc->tc_list) {
                        ret = -ENOMEM;
                        goto err_reg1;
                }

                for (i = 0;; i++) {
                        ret = of_parse_phandle_with_fixed_args(node, "ti,tptcs",
                                                               1, i, &tc_args);
                        if (ret || i == ecc->num_tc)
                                break;

                        ecc->tc_list[i].node = tc_args.np;
                        ecc->tc_list[i].id = i;
                        queue_priority_mapping[i][1] = tc_args.args[0];
                        if (queue_priority_mapping[i][1] > lowest_priority) {
                                lowest_priority = queue_priority_mapping[i][1];
                                info->default_queue = i;
                        }
                }

                /* See if we have optional dma-channel-mask array */
                array_max = DIV_ROUND_UP(ecc->num_channels, BITS_PER_TYPE(u32));
                ret = of_property_read_variable_u32_array(node,
                                                "dma-channel-mask",
                                                (u32 *)ecc->channels_mask,
                                                1, array_max);
                if (ret > 0 && ret != array_max)
                        dev_warn(dev, "dma-channel-mask is not complete.\n");
                else if (ret == -EOVERFLOW || ret == -ENODATA)
                        dev_warn(dev,
                                 "dma-channel-mask is out of range or empty\n");
        }

        /* Event queue priority mapping */
        for (i = 0; queue_priority_mapping[i][0] != -1; i++)
                edma_assign_priority_to_queue(ecc, queue_priority_mapping[i][0],
                                              queue_priority_mapping[i][1]);

        edma_write_array2(ecc, EDMA_DRAE, 0, 0, 0x0);
        edma_write_array2(ecc, EDMA_DRAE, 0, 1, 0x0);
        edma_write_array(ecc, EDMA_QRAE, 0, 0x0);

        ecc->info = info;

        /* Init the dma device and channels */
        edma_dma_init(ecc, legacy_mode);

        for (i = 0; i < ecc->num_channels; i++) {
                /* Do not touch reserved channels */
                if (!test_bit(i, ecc->channels_mask))
                        continue;

                /* Assign all channels to the default queue */
                edma_assign_channel_eventq(&ecc->slave_chans[i],
                                           info->default_queue);
                /* Set entry slot to the dummy slot */
                edma_set_chmap(&ecc->slave_chans[i], ecc->dummy_slot);
        }

        ecc->dma_slave.filter.map = info->slave_map;
        ecc->dma_slave.filter.mapcnt = info->slavecnt;
        ecc->dma_slave.filter.fn = edma_filter_fn;

        ret = dma_async_device_register(&ecc->dma_slave);
        if (ret) {
                dev_err(dev, "slave ddev registration failed (%d)\n", ret);
                goto err_reg1;
        }

        if (ecc->dma_memcpy) {
                ret = dma_async_device_register(ecc->dma_memcpy);
                if (ret) {
                        dev_err(dev, "memcpy ddev registration failed (%d)\n",
                                ret);
                        dma_async_device_unregister(&ecc->dma_slave);
                        goto err_reg1;
                }
        }

        if (node)
                of_dma_controller_register(node, of_edma_xlate, ecc);

        dev_info(dev, "TI EDMA DMA engine driver\n");

        return 0;

err_reg1:
        edma_free_slot(ecc, ecc->dummy_slot);
err_disable_pm:
        pm_runtime_put_sync(dev);
        pm_runtime_disable(dev);
        return ret;
}

static void edma_cleanupp_vchan(struct dma_device *dmadev)
{
        struct edma_chan *echan, *_echan;

        list_for_each_entry_safe(echan, _echan,
                        &dmadev->channels, vchan.chan.device_node) {
                list_del(&echan->vchan.chan.device_node);
                tasklet_kill(&echan->vchan.task);
        }
}

static int edma_remove(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct edma_cc *ecc = dev_get_drvdata(dev);

        devm_free_irq(dev, ecc->ccint, ecc);
        devm_free_irq(dev, ecc->ccerrint, ecc);

        edma_cleanupp_vchan(&ecc->dma_slave);

        if (dev->of_node)
                of_dma_controller_free(dev->of_node);
        dma_async_device_unregister(&ecc->dma_slave);
        if (ecc->dma_memcpy)
                dma_async_device_unregister(ecc->dma_memcpy);
        edma_free_slot(ecc, ecc->dummy_slot);
        pm_runtime_put_sync(dev);
        pm_runtime_disable(dev);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int edma_pm_suspend(struct device *dev)
{
        struct edma_cc *ecc = dev_get_drvdata(dev);
        struct edma_chan *echan = ecc->slave_chans;
        int i;

        for (i = 0; i < ecc->num_channels; i++) {
                if (echan[i].alloced)
                        edma_setup_interrupt(&echan[i], false);
        }

        return 0;
}

static int edma_pm_resume(struct device *dev)
{
        struct edma_cc *ecc = dev_get_drvdata(dev);
        struct edma_chan *echan = ecc->slave_chans;
        int i;
        s8 (*queue_priority_mapping)[2];

        /* re initialize dummy slot to dummy param set */
        edma_write_slot(ecc, ecc->dummy_slot, &dummy_paramset);

        queue_priority_mapping = ecc->info->queue_priority_mapping;

        /* Event queue priority mapping */
        for (i = 0; queue_priority_mapping[i][0] != -1; i++)
                edma_assign_priority_to_queue(ecc, queue_priority_mapping[i][0],
                                              queue_priority_mapping[i][1]);

        for (i = 0; i < ecc->num_channels; i++) {
                if (echan[i].alloced) {
                        /* ensure access through shadow region 0 */
                        edma_or_array2(ecc, EDMA_DRAE, 0,
                                       EDMA_REG_ARRAY_INDEX(i),
                                       EDMA_CHANNEL_BIT(i));

                        edma_setup_interrupt(&echan[i], true);

                        /* Set up channel -> slot mapping for the entry slot */
                        edma_set_chmap(&echan[i], echan[i].slot[0]);
                }
        }

        return 0;
}
#endif

static const struct dev_pm_ops edma_pm_ops = {
        SET_LATE_SYSTEM_SLEEP_PM_OPS(edma_pm_suspend, edma_pm_resume)
};

static struct platform_driver edma_driver = {
        .probe          = edma_probe,
        .remove         = edma_remove,
        .driver = {
                .name   = "edma",
                .pm     = &edma_pm_ops,
                .of_match_table = edma_of_ids,
        },
};

static int edma_tptc_probe(struct platform_device *pdev)
{
        pm_runtime_enable(&pdev->dev);
        return pm_runtime_get_sync(&pdev->dev);
}

static struct platform_driver edma_tptc_driver = {
        .probe          = edma_tptc_probe,
        .driver = {
                .name   = "edma3-tptc",
                .of_match_table = edma_tptc_of_ids,
        },
};

static bool edma_filter_fn(struct dma_chan *chan, void *param)
{
        bool match = false;

        if (chan->device->dev->driver == &edma_driver.driver) {
                struct edma_chan *echan = to_edma_chan(chan);
                unsigned ch_req = *(unsigned *)param;
                if (ch_req == echan->ch_num) {
                        /* The channel is going to be used as HW synchronized */
                        echan->hw_triggered = true;
                        match = true;
                }
        }
        return match;
}

static int edma_init(void)
{
        int ret;

        ret = platform_driver_register(&edma_tptc_driver);
        if (ret)
                return ret;

        return platform_driver_register(&edma_driver);
}
subsys_initcall(edma_init);

static void __exit edma_exit(void)
{
        platform_driver_unregister(&edma_driver);
        platform_driver_unregister(&edma_tptc_driver);
}
module_exit(edma_exit);

MODULE_AUTHOR("Matt Porter <matt.porter@linaro.org>");
MODULE_DESCRIPTION("TI EDMA DMA engine driver");
MODULE_LICENSE("GPL v2");