/*
 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Copyright (C) 2010 Samsung Electronics Co. Ltd.
 *      Jaswinder Singh <jassi.brar@samsung.com>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/amba/bus.h>
#include <linux/amba/pl330.h>
#include <linux/scatterlist.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include <linux/err.h>
#include <linux/pm_runtime.h>

#include "dmaengine.h"
#define PL330_MAX_CHAN          8
#define PL330_MAX_IRQS          32
#define PL330_MAX_PERI          32

enum pl330_cachectrl {
        CCTRL0,         /* Noncacheable and nonbufferable */
        CCTRL1,         /* Bufferable only */
        CCTRL2,         /* Cacheable, but do not allocate */
        CCTRL3,         /* Cacheable and bufferable, but do not allocate */
        INVALID1,       /* AWCACHE = 0x1000 */
        INVALID2,
        CCTRL6,         /* Cacheable write-through, allocate on writes only */
        CCTRL7,         /* Cacheable write-back, allocate on writes only */
};

enum pl330_byteswap {
        SWAP_NO,
        SWAP_2,
        SWAP_4,
        SWAP_8,
        SWAP_16,
};

/* Register and Bit field Definitions */
#define DS                      0x0
#define DS_ST_STOP              0x0
#define DS_ST_EXEC              0x1
#define DS_ST_CMISS             0x2
#define DS_ST_UPDTPC            0x3
#define DS_ST_WFE               0x4
#define DS_ST_ATBRR             0x5
#define DS_ST_QBUSY             0x6
#define DS_ST_WFP               0x7
#define DS_ST_KILL              0x8
#define DS_ST_CMPLT             0x9
#define DS_ST_FLTCMP            0xe
#define DS_ST_FAULT             0xf

#define DPC                     0x4
#define INTEN                   0x20
#define ES                      0x24
#define INTSTATUS               0x28
#define INTCLR                  0x2c
#define FSM                     0x30
#define FSC                     0x34
#define FTM                     0x38

#define _FTC                    0x40
#define FTC(n)                  (_FTC + (n)*0x4)

#define _CS                     0x100
#define CS(n)                   (_CS + (n)*0x8)
#define CS_CNS                  (1 << 21)

#define _CPC                    0x104
#define CPC(n)                  (_CPC + (n)*0x8)

#define _SA                     0x400
#define SA(n)                   (_SA + (n)*0x20)

#define _DA                     0x404
#define DA(n)                   (_DA + (n)*0x20)

#define _CC                     0x408
#define CC(n)                   (_CC + (n)*0x20)

#define CC_SRCINC               (1 << 0)
#define CC_DSTINC               (1 << 14)
#define CC_SRCPRI               (1 << 8)
#define CC_DSTPRI               (1 << 22)
#define CC_SRCNS                (1 << 9)
#define CC_DSTNS                (1 << 23)
#define CC_SRCIA                (1 << 10)
#define CC_DSTIA                (1 << 24)
#define CC_SRCBRSTLEN_SHFT      4
#define CC_DSTBRSTLEN_SHFT      18
#define CC_SRCBRSTSIZE_SHFT     1
#define CC_DSTBRSTSIZE_SHFT     15
#define CC_SRCCCTRL_SHFT        11
#define CC_SRCCCTRL_MASK        0x7
#define CC_DSTCCTRL_SHFT        25
#define CC_DRCCCTRL_MASK        0x7
#define CC_SWAP_SHFT            28

#define _LC0                    0x40c
#define LC0(n)                  (_LC0 + (n)*0x20)

#define _LC1                    0x410
#define LC1(n)                  (_LC1 + (n)*0x20)

#define DBGSTATUS               0xd00
#define DBG_BUSY                (1 << 0)

#define DBGCMD                  0xd04
#define DBGINST0                0xd08
#define DBGINST1                0xd0c

#define CR0                     0xe00
#define CR1                     0xe04
#define CR2                     0xe08
#define CR3                     0xe0c
#define CR4                     0xe10
#define CRD                     0xe14

#define PERIPH_ID               0xfe0
#define PERIPH_REV_SHIFT        20
#define PERIPH_REV_MASK         0xf
#define PERIPH_REV_R0P0         0
#define PERIPH_REV_R1P0         1
#define PERIPH_REV_R1P1         2

#define CR0_PERIPH_REQ_SET      (1 << 0)
#define CR0_BOOT_EN_SET         (1 << 1)
#define CR0_BOOT_MAN_NS         (1 << 2)
#define CR0_NUM_CHANS_SHIFT     4
#define CR0_NUM_CHANS_MASK      0x7
#define CR0_NUM_PERIPH_SHIFT    12
#define CR0_NUM_PERIPH_MASK     0x1f
#define CR0_NUM_EVENTS_SHIFT    17
#define CR0_NUM_EVENTS_MASK     0x1f

#define CR1_ICACHE_LEN_SHIFT    0
#define CR1_ICACHE_LEN_MASK     0x7
#define CR1_NUM_ICACHELINES_SHIFT       4
#define CR1_NUM_ICACHELINES_MASK        0xf

#define CRD_DATA_WIDTH_SHIFT    0
#define CRD_DATA_WIDTH_MASK     0x7
#define CRD_WR_CAP_SHIFT        4
#define CRD_WR_CAP_MASK         0x7
#define CRD_WR_Q_DEP_SHIFT      8
#define CRD_WR_Q_DEP_MASK       0xf
#define CRD_RD_CAP_SHIFT        12
#define CRD_RD_CAP_MASK         0x7
#define CRD_RD_Q_DEP_SHIFT      16
#define CRD_RD_Q_DEP_MASK       0xf
#define CRD_DATA_BUFF_SHIFT     20
#define CRD_DATA_BUFF_MASK      0x3ff

#define PART                    0x330
#define DESIGNER                0x41
#define REVISION                0x0
#define INTEG_CFG               0x0
#define PERIPH_ID_VAL           ((PART << 0) | (DESIGNER << 12))

#define PL330_STATE_STOPPED             (1 << 0)
#define PL330_STATE_EXECUTING           (1 << 1)
#define PL330_STATE_WFE                 (1 << 2)
#define PL330_STATE_FAULTING            (1 << 3)
#define PL330_STATE_COMPLETING          (1 << 4)
#define PL330_STATE_WFP                 (1 << 5)
#define PL330_STATE_KILLING             (1 << 6)
#define PL330_STATE_FAULT_COMPLETING    (1 << 7)
#define PL330_STATE_CACHEMISS           (1 << 8)
#define PL330_STATE_UPDTPC              (1 << 9)
#define PL330_STATE_ATBARRIER           (1 << 10)
#define PL330_STATE_QUEUEBUSY           (1 << 11)
#define PL330_STATE_INVALID             (1 << 15)

#define PL330_STABLE_STATES (PL330_STATE_STOPPED | PL330_STATE_EXECUTING \
                                | PL330_STATE_WFE | PL330_STATE_FAULTING)

#define CMD_DMAADDH             0x54
#define CMD_DMAEND              0x00
#define CMD_DMAFLUSHP           0x35
#define CMD_DMAGO               0xa0
#define CMD_DMALD               0x04
#define CMD_DMALDP              0x25
#define CMD_DMALP               0x20
#define CMD_DMALPEND            0x28
#define CMD_DMAKILL             0x01
#define CMD_DMAMOV              0xbc
#define CMD_DMANOP              0x18
#define CMD_DMARMB              0x12
#define CMD_DMASEV              0x34
#define CMD_DMAST               0x08
#define CMD_DMASTP              0x29
#define CMD_DMASTZ              0x0c
#define CMD_DMAWFE              0x36
#define CMD_DMAWFP              0x30
#define CMD_DMAWMB              0x13

#define SZ_DMAADDH              3
#define SZ_DMAEND               1
#define SZ_DMAFLUSHP            2
#define SZ_DMALD                1
#define SZ_DMALDP               2
#define SZ_DMALP                2
#define SZ_DMALPEND             2
#define SZ_DMAKILL              1
#define SZ_DMAMOV               6
#define SZ_DMANOP               1
#define SZ_DMARMB               1
#define SZ_DMASEV               2
#define SZ_DMAST                1
#define SZ_DMASTP               2
#define SZ_DMASTZ               1
#define SZ_DMAWFE               2
#define SZ_DMAWFP               2
#define SZ_DMAWMB               1
#define SZ_DMAGO                6

#define BRST_LEN(ccr)           ((((ccr) >> CC_SRCBRSTLEN_SHFT) & 0xf) + 1)
#define BRST_SIZE(ccr)          (1 << (((ccr) >> CC_SRCBRSTSIZE_SHFT) & 0x7))

#define BYTE_TO_BURST(b, ccr)   ((b) / BRST_SIZE(ccr) / BRST_LEN(ccr))
#define BURST_TO_BYTE(c, ccr)   ((c) * BRST_SIZE(ccr) * BRST_LEN(ccr))

/*
 * With 256 bytes, we can do more than 2.5MB and 5MB xfers per req
 * at 1byte/burst for P<->M and M<->M respectively.
 * For typical scenario, at 1word/burst, 10MB and 20MB xfers per req
 * should be enough for P<->M and M<->M respectively.
 */
#define MCODE_BUFF_PER_REQ      256

/* Use this _only_ to wait on transient states */
#define UNTIL(t, s)     while (!(_state(t) & (s))) cpu_relax();

#ifdef PL330_DEBUG_MCGEN
static unsigned cmd_line;
#define PL330_DBGCMD_DUMP(off, x...)    do { \
                                                printk("%x:", cmd_line); \
                                                printk(x); \
                                                cmd_line += off; \
                                        } while (0)
#define PL330_DBGMC_START(addr)         (cmd_line = addr)
#else
#define PL330_DBGCMD_DUMP(off, x...)    do {} while (0)
#define PL330_DBGMC_START(addr)         do {} while (0)
#endif

/* The number of default descriptors */

#define NR_DEFAULT_DESC 16

/* Delay for runtime PM autosuspend, ms */
#define PL330_AUTOSUSPEND_DELAY 20

/* Populated by the PL330 core driver for DMA API driver's info */
struct pl330_config {
        u32     periph_id;
#define DMAC_MODE_NS    (1 << 0)
        unsigned int    mode;
        unsigned int    data_bus_width:10; /* In number of bits */
        unsigned int    data_buf_dep:11;
        unsigned int    num_chan:4;
        unsigned int    num_peri:6;
        u32             peri_ns;
        unsigned int    num_events:6;
        u32             irq_ns;
};

/**
 * Request Configuration.
 * The PL330 core does not modify this and uses the last
 * working configuration if the request doesn't provide any.
 *
 * The Client may want to provide this info only for the
 * first request and a request with new settings.
 */
struct pl330_reqcfg {
        /* Address Incrementing */
        unsigned dst_inc:1;
        unsigned src_inc:1;

        /*
         * For now, the SRC & DST protection levels
         * and burst size/length are assumed same.
         */
        bool nonsecure;
        bool privileged;
        bool insnaccess;
        unsigned brst_len:5;
        unsigned brst_size:3; /* in power of 2 */

        enum pl330_cachectrl dcctl;
        enum pl330_cachectrl scctl;
        enum pl330_byteswap swap;
        struct pl330_config *pcfg;
};

/*
 * One cycle of DMAC operation.
 * There may be more than one xfer in a request.
 */
struct pl330_xfer {
        u32 src_addr;
        u32 dst_addr;
        /* Size to xfer */
        u32 bytes;
};

/* The xfer callbacks are made with one of these arguments. */
enum pl330_op_err {
        /* The all xfers in the request were success. */
        PL330_ERR_NONE,
        /* If req aborted due to global error. */
        PL330_ERR_ABORT,
        /* If req failed due to problem with Channel. */
        PL330_ERR_FAIL,
};

enum dmamov_dst {
        SAR = 0,
        CCR,
        DAR,
};

enum pl330_dst {
        SRC = 0,
        DST,
};

enum pl330_cond {
        SINGLE,
        BURST,
        ALWAYS,
};

struct dma_pl330_desc;

struct _pl330_req {
        u32 mc_bus;
        void *mc_cpu;
        struct dma_pl330_desc *desc;
};

/* ToBeDone for tasklet */
struct _pl330_tbd {
        bool reset_dmac;
        bool reset_mngr;
        u8 reset_chan;
};

/* A DMAC Thread */
struct pl330_thread {
        u8 id;
        int ev;
        /* If the channel is not yet acquired by any client */
        bool free;
        /* Parent DMAC */
        struct pl330_dmac *dmac;
        /* Only two at a time */
        struct _pl330_req req[2];
        /* Index of the last enqueued request */
        unsigned lstenq;
        /* Index of the last submitted request or -1 if the DMA is stopped */
        int req_running;
};

enum pl330_dmac_state {
        UNINIT,
        INIT,
        DYING,
};

enum desc_status {
        /* In the DMAC pool */
        FREE,
        /*
         * Allocated to some channel during prep_xxx
         * Also may be sitting on the work_list.
         */
        PREP,
        /*
         * Sitting on the work_list and already submitted
         * to the PL330 core. Not more than two descriptors
         * of a channel can be BUSY at any time.
         */
        BUSY,
        /*
         * Sitting on the channel work_list but xfer done
         * by PL330 core
         */
        DONE,
};

struct dma_pl330_chan {
        /* Schedule desc completion */
        struct tasklet_struct task;

        /* DMA-Engine Channel */
        struct dma_chan chan;

        /* List of submitted descriptors */
        struct list_head submitted_list;
        /* List of issued descriptors */
        struct list_head work_list;
        /* List of completed descriptors */
        struct list_head completed_list;

        /* Pointer to the DMAC that manages this channel,
         * NULL if the channel is available to be acquired.
         * As the parent, this DMAC also provides descriptors
         * to the channel.
         */
        struct pl330_dmac *dmac;

        /* To protect channel manipulation */
        spinlock_t lock;

        /*
         * Hardware channel thread of PL330 DMAC. NULL if the channel is
         * available.
         */
        struct pl330_thread *thread;

        /* For D-to-M and M-to-D channels */
        int burst_sz; /* the peripheral fifo width */
        int burst_len; /* the number of burst */
        dma_addr_t fifo_addr;

        /* for cyclic capability */
        bool cyclic;
};

struct pl330_dmac {
        /* DMA-Engine Device */
        struct dma_device ddma;

        /* Holds info about sg limitations */
        struct device_dma_parameters dma_parms;

        /* Pool of descriptors available for the DMAC's channels */
        struct list_head desc_pool;
        /* To protect desc_pool manipulation */
        spinlock_t pool_lock;

        /* Size of MicroCode buffers for each channel. */
        unsigned mcbufsz;
        /* ioremap'ed address of PL330 registers. */
        void __iomem    *base;
        /* Populated by the PL330 core driver during pl330_add */
        struct pl330_config     pcfg;

        spinlock_t              lock;
        /* Maximum possible events/irqs */
        int                     events[32];
        /* BUS address of MicroCode buffer */
        dma_addr_t              mcode_bus;
        /* CPU address of MicroCode buffer */
        void                    *mcode_cpu;
        /* List of all Channel threads */
        struct pl330_thread     *channels;
        /* Pointer to the MANAGER thread */
        struct pl330_thread     *manager;
        /* To handle bad news in interrupt */
        struct tasklet_struct   tasks;
        struct _pl330_tbd       dmac_tbd;
        /* State of DMAC operation */
        enum pl330_dmac_state   state;
        /* Holds list of reqs with due callbacks */
        struct list_head        req_done;

        /* Peripheral channels connected to this DMAC */
        unsigned int num_peripherals;
        struct dma_pl330_chan *peripherals; /* keep at end */
};

struct dma_pl330_desc {
        /* To attach to a queue as child */
        struct list_head node;

        /* Descriptor for the DMA Engine API */
        struct dma_async_tx_descriptor txd;

        /* Xfer for PL330 core */
        struct pl330_xfer px;

        struct pl330_reqcfg rqcfg;

        enum desc_status status;

        int bytes_requested;
        bool last;

        /* The channel which currently holds this desc */
        struct dma_pl330_chan *pchan;

        enum dma_transfer_direction rqtype;
        /* Index of peripheral for the xfer. */
        unsigned peri:5;
        /* Hook to attach to DMAC's list of reqs with due callback */
        struct list_head rqd;
};

struct _xfer_spec {
        u32 ccr;
        struct dma_pl330_desc *desc;
};

static inline bool _queue_empty(struct pl330_thread *thrd)
{
        return thrd->req[0].desc == NULL && thrd->req[1].desc == NULL;
}

static inline bool _queue_full(struct pl330_thread *thrd)
{
        return thrd->req[0].desc != NULL && thrd->req[1].desc != NULL;
}

static inline bool is_manager(struct pl330_thread *thrd)
{
        return thrd->dmac->manager == thrd;
}

/* If manager of the thread is in Non-Secure mode */
static inline bool _manager_ns(struct pl330_thread *thrd)
{
        return (thrd->dmac->pcfg.mode & DMAC_MODE_NS) ? true : false;
}

static inline u32 get_revision(u32 periph_id)
{
        return (periph_id >> PERIPH_REV_SHIFT) & PERIPH_REV_MASK;
}

static inline u32 _emit_ADDH(unsigned dry_run, u8 buf[],
                enum pl330_dst da, u16 val)
{
        if (dry_run)
                return SZ_DMAADDH;

        buf[0] = CMD_DMAADDH;
        buf[0] |= (da << 1);
        *((__le16 *)&buf[1]) = cpu_to_le16(val);

        PL330_DBGCMD_DUMP(SZ_DMAADDH, "\tDMAADDH %s %u\n",
                da == 1 ? "DA" : "SA", val);

        return SZ_DMAADDH;
}

static inline u32 _emit_END(unsigned dry_run, u8 buf[])
{
        if (dry_run)
                return SZ_DMAEND;

        buf[0] = CMD_DMAEND;

        PL330_DBGCMD_DUMP(SZ_DMAEND, "\tDMAEND\n");

        return SZ_DMAEND;
}

static inline u32 _emit_FLUSHP(unsigned dry_run, u8 buf[], u8 peri)
{
        if (dry_run)
                return SZ_DMAFLUSHP;

        buf[0] = CMD_DMAFLUSHP;

        peri &= 0x1f;
        peri <<= 3;
        buf[1] = peri;

        PL330_DBGCMD_DUMP(SZ_DMAFLUSHP, "\tDMAFLUSHP %u\n", peri >> 3);

        return SZ_DMAFLUSHP;
}

static inline u32 _emit_LD(unsigned dry_run, u8 buf[],  enum pl330_cond cond)
{
        if (dry_run)
                return SZ_DMALD;

        buf[0] = CMD_DMALD;

        if (cond == SINGLE)
                buf[0] |= (0 << 1) | (1 << 0);
        else if (cond == BURST)
                buf[0] |= (1 << 1) | (1 << 0);

        PL330_DBGCMD_DUMP(SZ_DMALD, "\tDMALD%c\n",
                cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'A'));

        return SZ_DMALD;
}

static inline u32 _emit_LDP(unsigned dry_run, u8 buf[],
                enum pl330_cond cond, u8 peri)
{
        if (dry_run)
                return SZ_DMALDP;

        buf[0] = CMD_DMALDP;

        if (cond == BURST)
                buf[0] |= (1 << 1);

        peri &= 0x1f;
        peri <<= 3;
        buf[1] = peri;

        PL330_DBGCMD_DUMP(SZ_DMALDP, "\tDMALDP%c %u\n",
                cond == SINGLE ? 'S' : 'B', peri >> 3);

        return SZ_DMALDP;
}

static inline u32 _emit_LP(unsigned dry_run, u8 buf[],
                unsigned loop, u8 cnt)
{
        if (dry_run)
                return SZ_DMALP;

        buf[0] = CMD_DMALP;

        if (loop)
                buf[0] |= (1 << 1);

        cnt--; /* DMAC increments by 1 internally */
        buf[1] = cnt;

        PL330_DBGCMD_DUMP(SZ_DMALP, "\tDMALP_%c %u\n", loop ? '1' : '0', cnt);

        return SZ_DMALP;
}

struct _arg_LPEND {
        enum pl330_cond cond;
        bool forever;
        unsigned loop;
        u8 bjump;
};

static inline u32 _emit_LPEND(unsigned dry_run, u8 buf[],
                const struct _arg_LPEND *arg)
{
        enum pl330_cond cond = arg->cond;
        bool forever = arg->forever;
        unsigned loop = arg->loop;
        u8 bjump = arg->bjump;

        if (dry_run)
                return SZ_DMALPEND;

        buf[0] = CMD_DMALPEND;

        if (loop)
                buf[0] |= (1 << 2);

        if (!forever)
                buf[0] |= (1 << 4);

        if (cond == SINGLE)
                buf[0] |= (0 << 1) | (1 << 0);
        else if (cond == BURST)
                buf[0] |= (1 << 1) | (1 << 0);

        buf[1] = bjump;

        PL330_DBGCMD_DUMP(SZ_DMALPEND, "\tDMALP%s%c_%c bjmpto_%x\n",
                        forever ? "FE" : "END",
                        cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'A'),
                        loop ? '1' : '0',
                        bjump);

        return SZ_DMALPEND;
}

static inline u32 _emit_KILL(unsigned dry_run, u8 buf[])
{
        if (dry_run)
                return SZ_DMAKILL;

        buf[0] = CMD_DMAKILL;

        return SZ_DMAKILL;
}

static inline u32 _emit_MOV(unsigned dry_run, u8 buf[],
                enum dmamov_dst dst, u32 val)
{
        if (dry_run)
                return SZ_DMAMOV;

        buf[0] = CMD_DMAMOV;
        buf[1] = dst;
        *((__le32 *)&buf[2]) = cpu_to_le32(val);

        PL330_DBGCMD_DUMP(SZ_DMAMOV, "\tDMAMOV %s 0x%x\n",
                dst == SAR ? "SAR" : (dst == DAR ? "DAR" : "CCR"), val);

        return SZ_DMAMOV;
}

static inline u32 _emit_NOP(unsigned dry_run, u8 buf[])
{
        if (dry_run)
                return SZ_DMANOP;

        buf[0] = CMD_DMANOP;

        PL330_DBGCMD_DUMP(SZ_DMANOP, "\tDMANOP\n");

        return SZ_DMANOP;
}

static inline u32 _emit_RMB(unsigned dry_run, u8 buf[])
{
        if (dry_run)
                return SZ_DMARMB;

        buf[0] = CMD_DMARMB;

        PL330_DBGCMD_DUMP(SZ_DMARMB, "\tDMARMB\n");

        return SZ_DMARMB;
}

static inline u32 _emit_SEV(unsigned dry_run, u8 buf[], u8 ev)
{
        if (dry_run)
                return SZ_DMASEV;

        buf[0] = CMD_DMASEV;

        ev &= 0x1f;
        ev <<= 3;
        buf[1] = ev;

        PL330_DBGCMD_DUMP(SZ_DMASEV, "\tDMASEV %u\n", ev >> 3);

        return SZ_DMASEV;
}

static inline u32 _emit_ST(unsigned dry_run, u8 buf[], enum pl330_cond cond)
{
        if (dry_run)
                return SZ_DMAST;

        buf[0] = CMD_DMAST;

        if (cond == SINGLE)
                buf[0] |= (0 << 1) | (1 << 0);
        else if (cond == BURST)
                buf[0] |= (1 << 1) | (1 << 0);

        PL330_DBGCMD_DUMP(SZ_DMAST, "\tDMAST%c\n",
                cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'A'));

        return SZ_DMAST;
}

static inline u32 _emit_STP(unsigned dry_run, u8 buf[],
                enum pl330_cond cond, u8 peri)
{
        if (dry_run)
                return SZ_DMASTP;

        buf[0] = CMD_DMASTP;

        if (cond == BURST)
                buf[0] |= (1 << 1);

        peri &= 0x1f;
        peri <<= 3;
        buf[1] = peri;

        PL330_DBGCMD_DUMP(SZ_DMASTP, "\tDMASTP%c %u\n",
                cond == SINGLE ? 'S' : 'B', peri >> 3);

        return SZ_DMASTP;
}

static inline u32 _emit_STZ(unsigned dry_run, u8 buf[])
{
        if (dry_run)
                return SZ_DMASTZ;

        buf[0] = CMD_DMASTZ;

        PL330_DBGCMD_DUMP(SZ_DMASTZ, "\tDMASTZ\n");

        return SZ_DMASTZ;
}

static inline u32 _emit_WFE(unsigned dry_run, u8 buf[], u8 ev,
                unsigned invalidate)
{
        if (dry_run)
                return SZ_DMAWFE;

        buf[0] = CMD_DMAWFE;

        ev &= 0x1f;
        ev <<= 3;
        buf[1] = ev;

        if (invalidate)
                buf[1] |= (1 << 1);

        PL330_DBGCMD_DUMP(SZ_DMAWFE, "\tDMAWFE %u%s\n",
                ev >> 3, invalidate ? ", I" : "");

        return SZ_DMAWFE;
}

static inline u32 _emit_WFP(unsigned dry_run, u8 buf[],
                enum pl330_cond cond, u8 peri)
{
        if (dry_run)
                return SZ_DMAWFP;

        buf[0] = CMD_DMAWFP;

        if (cond == SINGLE)
                buf[0] |= (0 << 1) | (0 << 0);
        else if (cond == BURST)
                buf[0] |= (1 << 1) | (0 << 0);
        else
                buf[0] |= (0 << 1) | (1 << 0);

        peri &= 0x1f;
        peri <<= 3;
        buf[1] = peri;

        PL330_DBGCMD_DUMP(SZ_DMAWFP, "\tDMAWFP%c %u\n",
                cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'P'), peri >> 3);

        return SZ_DMAWFP;
}

static inline u32 _emit_WMB(unsigned dry_run, u8 buf[])
{
        if (dry_run)
                return SZ_DMAWMB;

        buf[0] = CMD_DMAWMB;

        PL330_DBGCMD_DUMP(SZ_DMAWMB, "\tDMAWMB\n");

        return SZ_DMAWMB;
}

struct _arg_GO {
        u8 chan;
        u32 addr;
        unsigned ns;
};

static inline u32 _emit_GO(unsigned dry_run, u8 buf[],
                const struct _arg_GO *arg)
{
        u8 chan = arg->chan;
        u32 addr = arg->addr;
        unsigned ns = arg->ns;

        if (dry_run)
                return SZ_DMAGO;

        buf[0] = CMD_DMAGO;
        buf[0] |= (ns << 1);

        buf[1] = chan & 0x7;

        *((__le32 *)&buf[2]) = cpu_to_le32(addr);

        return SZ_DMAGO;
}

#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)

/* Returns Time-Out */
static bool _until_dmac_idle(struct pl330_thread *thrd)
{
        void __iomem *regs = thrd->dmac->base;
        unsigned long loops = msecs_to_loops(5);

        do {
                /* Until Manager is Idle */
                if (!(readl(regs + DBGSTATUS) & DBG_BUSY))
                        break;

                cpu_relax();
        } while (--loops);

        if (!loops)
                return true;

        return false;
}

static inline void _execute_DBGINSN(struct pl330_thread *thrd,
                u8 insn[], bool as_manager)
{
        void __iomem *regs = thrd->dmac->base;
        u32 val;

        val = (insn[0] << 16) | (insn[1] << 24);
        if (!as_manager) {
                val |= (1 << 0);
                val |= (thrd->id << 8); /* Channel Number */
        }
        writel(val, regs + DBGINST0);

        val = le32_to_cpu(*((__le32 *)&insn[2]));
        writel(val, regs + DBGINST1);

        /* If timed out due to halted state-machine */
        if (_until_dmac_idle(thrd)) {
                dev_err(thrd->dmac->ddma.dev, "DMAC halted!\n");
                return;
        }

        /* Get going */
        writel(0, regs + DBGCMD);
}

static inline u32 _state(struct pl330_thread *thrd)
{
        void __iomem *regs = thrd->dmac->base;
        u32 val;

        if (is_manager(thrd))
                val = readl(regs + DS) & 0xf;
        else
                val = readl(regs + CS(thrd->id)) & 0xf;

        switch (val) {
        case DS_ST_STOP:
                return PL330_STATE_STOPPED;
        case DS_ST_EXEC:
                return PL330_STATE_EXECUTING;
        case DS_ST_CMISS:
                return PL330_STATE_CACHEMISS;
        case DS_ST_UPDTPC:
                return PL330_STATE_UPDTPC;
        case DS_ST_WFE:
                return PL330_STATE_WFE;
        case DS_ST_FAULT:
                return PL330_STATE_FAULTING;
        case DS_ST_ATBRR:
                if (is_manager(thrd))
                        return PL330_STATE_INVALID;
                else
                        return PL330_STATE_ATBARRIER;
        case DS_ST_QBUSY:
                if (is_manager(thrd))
                        return PL330_STATE_INVALID;
                else
                        return PL330_STATE_QUEUEBUSY;
        case DS_ST_WFP:
                if (is_manager(thrd))
                        return PL330_STATE_INVALID;
                else
                        return PL330_STATE_WFP;
        case DS_ST_KILL:
                if (is_manager(thrd))
                        return PL330_STATE_INVALID;
                else
                        return PL330_STATE_KILLING;
        case DS_ST_CMPLT:
                if (is_manager(thrd))
                        return PL330_STATE_INVALID;
                else
                        return PL330_STATE_COMPLETING;
        case DS_ST_FLTCMP:
                if (is_manager(thrd))
                        return PL330_STATE_INVALID;
                else
                        return PL330_STATE_FAULT_COMPLETING;
        default:
                return PL330_STATE_INVALID;
        }
}

static void _stop(struct pl330_thread *thrd)
{
        void __iomem *regs = thrd->dmac->base;
        u8 insn[6] = {0, 0, 0, 0, 0, 0};

        if (_state(thrd) == PL330_STATE_FAULT_COMPLETING)
                UNTIL(thrd, PL330_STATE_FAULTING | PL330_STATE_KILLING);

        /* Return if nothing needs to be done */
        if (_state(thrd) == PL330_STATE_COMPLETING
                  || _state(thrd) == PL330_STATE_KILLING
                  || _state(thrd) == PL330_STATE_STOPPED)
                return;

        _emit_KILL(0, insn);

        /* Stop generating interrupts for SEV */
        writel(readl(regs + INTEN) & ~(1 << thrd->ev), regs + INTEN);

        _execute_DBGINSN(thrd, insn, is_manager(thrd));
}

/* Start doing req 'idx' of thread 'thrd' */
static bool _trigger(struct pl330_thread *thrd)
{
        void __iomem *regs = thrd->dmac->base;
        struct _pl330_req *req;
        struct dma_pl330_desc *desc;
        struct _arg_GO go;
        unsigned ns;
        u8 insn[6] = {0, 0, 0, 0, 0, 0};
        int idx;

        /* Return if already ACTIVE */
        if (_state(thrd) != PL330_STATE_STOPPED)
                return true;

        idx = 1 - thrd->lstenq;
        if (thrd->req[idx].desc != NULL) {
                req = &thrd->req[idx];
        } else {
                idx = thrd->lstenq;
                if (thrd->req[idx].desc != NULL)
                        req = &thrd->req[idx];
                else
                        req = NULL;
        }

        /* Return if no request */
        if (!req)
                return true;

        /* Return if req is running */
        if (idx == thrd->req_running)
                return true;

        desc = req->desc;

        ns = desc->rqcfg.nonsecure ? 1 : 0;

        /* See 'Abort Sources' point-4 at Page 2-25 */
        if (_manager_ns(thrd) && !ns)
                dev_info(thrd->dmac->ddma.dev, "%s:%d Recipe for ABORT!\n",
                        __func__, __LINE__);

        go.chan = thrd->id;
        go.addr = req->mc_bus;
        go.ns = ns;
        _emit_GO(0, insn, &go);

        /* Set to generate interrupts for SEV */
        writel(readl(regs + INTEN) | (1 << thrd->ev), regs + INTEN);

        /* Only manager can execute GO */
        _execute_DBGINSN(thrd, insn, true);

        thrd->req_running = idx;

        return true;
}

static bool _start(struct pl330_thread *thrd)
{
        switch (_state(thrd)) {
        case PL330_STATE_FAULT_COMPLETING:
                UNTIL(thrd, PL330_STATE_FAULTING | PL330_STATE_KILLING);

                if (_state(thrd) == PL330_STATE_KILLING)
                        UNTIL(thrd, PL330_STATE_STOPPED)

        case PL330_STATE_FAULTING:
                _stop(thrd);

        case PL330_STATE_KILLING:
        case PL330_STATE_COMPLETING:
                UNTIL(thrd, PL330_STATE_STOPPED)

        case PL330_STATE_STOPPED:
                return _trigger(thrd);

        case PL330_STATE_WFP:
        case PL330_STATE_QUEUEBUSY:
        case PL330_STATE_ATBARRIER:
        case PL330_STATE_UPDTPC:
        case PL330_STATE_CACHEMISS:
        case PL330_STATE_EXECUTING:
                return true;

        case PL330_STATE_WFE: /* For RESUME, nothing yet */
        default:
                return false;
        }
}

static inline int _ldst_memtomem(unsigned dry_run, u8 buf[],
                const struct _xfer_spec *pxs, int cyc)
{
        int off = 0;
        struct pl330_config *pcfg = pxs->desc->rqcfg.pcfg;

        /* check lock-up free version */
        if (get_revision(pcfg->periph_id) >= PERIPH_REV_R1P0) {
                while (cyc--) {
                        off += _emit_LD(dry_run, &buf[off], ALWAYS);
                        off += _emit_ST(dry_run, &buf[off], ALWAYS);
                }
        } else {
                while (cyc--) {
                        off += _emit_LD(dry_run, &buf[off], ALWAYS);
                        off += _emit_RMB(dry_run, &buf[off]);
                        off += _emit_ST(dry_run, &buf[off], ALWAYS);
                        off += _emit_WMB(dry_run, &buf[off]);
                }
        }

        return off;
}

static inline int _ldst_devtomem(unsigned dry_run, u8 buf[],
                const struct _xfer_spec *pxs, int cyc)
{
        int off = 0;

        while (cyc--) {
                off += _emit_WFP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
                off += _emit_LDP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
                off += _emit_ST(dry_run, &buf[off], ALWAYS);
                off += _emit_FLUSHP(dry_run, &buf[off], pxs->desc->peri);
        }

        return off;
}

static inline int _ldst_memtodev(unsigned dry_run, u8 buf[],
                const struct _xfer_spec *pxs, int cyc)
{
        int off = 0;

        while (cyc--) {
                off += _emit_WFP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
                off += _emit_LD(dry_run, &buf[off], ALWAYS);
                off += _emit_STP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
                off += _emit_FLUSHP(dry_run, &buf[off], pxs->desc->peri);
        }

        return off;
}

static int _bursts(unsigned dry_run, u8 buf[],
                const struct _xfer_spec *pxs, int cyc)
{
        int off = 0;

        switch (pxs->desc->rqtype) {
        case DMA_MEM_TO_DEV:
                off += _ldst_memtodev(dry_run, &buf[off], pxs, cyc);
                break;
        case DMA_DEV_TO_MEM:
                off += _ldst_devtomem(dry_run, &buf[off], pxs, cyc);
                break;
        case DMA_MEM_TO_MEM:
                off += _ldst_memtomem(dry_run, &buf[off], pxs, cyc);
                break;
        default:
                off += 0x40000000; /* Scare off the Client */
                break;
        }

        return off;
}

/* Returns bytes consumed and updates bursts */
static inline int _loop(unsigned dry_run, u8 buf[],
                unsigned long *bursts, const struct _xfer_spec *pxs)
{
        int cyc, cycmax, szlp, szlpend, szbrst, off;
        unsigned lcnt0, lcnt1, ljmp0, ljmp1;
        struct _arg_LPEND lpend;

        if (*bursts == 1)
                return _bursts(dry_run, buf, pxs, 1);

        /* Max iterations possible in DMALP is 256 */
        if (*bursts >= 256*256) {
                lcnt1 = 256;
                lcnt0 = 256;
                cyc = *bursts / lcnt1 / lcnt0;
        } else if (*bursts > 256) {
                lcnt1 = 256;
                lcnt0 = *bursts / lcnt1;
                cyc = 1;
        } else {
                lcnt1 = *bursts;
                lcnt0 = 0;
                cyc = 1;
        }

        szlp = _emit_LP(1, buf, 0, 0);
        szbrst = _bursts(1, buf, pxs, 1);

        lpend.cond = ALWAYS;
        lpend.forever = false;
        lpend.loop = 0;
        lpend.bjump = 0;
        szlpend = _emit_LPEND(1, buf, &lpend);

        if (lcnt0) {
                szlp *= 2;
                szlpend *= 2;
        }

        /*
         * Max bursts that we can unroll due to limit on the
         * size of backward jump that can be encoded in DMALPEND
         * which is 8-bits and hence 255
         */
        cycmax = (255 - (szlp + szlpend)) / szbrst;

        cyc = (cycmax < cyc) ? cycmax : cyc;

        off = 0;

        if (lcnt0) {
                off += _emit_LP(dry_run, &buf[off], 0, lcnt0);
                ljmp0 = off;
        }

        off += _emit_LP(dry_run, &buf[off], 1, lcnt1);
        ljmp1 = off;

        off += _bursts(dry_run, &buf[off], pxs, cyc);

        lpend.cond = ALWAYS;
        lpend.forever = false;
        lpend.loop = 1;
        lpend.bjump = off - ljmp1;
        off += _emit_LPEND(dry_run, &buf[off], &lpend);

        if (lcnt0) {
                lpend.cond = ALWAYS;
                lpend.forever = false;
                lpend.loop = 0;
                lpend.bjump = off - ljmp0;
                off += _emit_LPEND(dry_run, &buf[off], &lpend);
        }

        *bursts = lcnt1 * cyc;
        if (lcnt0)
                *bursts *= lcnt0;

        return off;
}

static inline int _setup_loops(unsigned dry_run, u8 buf[],
                const struct _xfer_spec *pxs)
{
        struct pl330_xfer *x = &pxs->desc->px;
        u32 ccr = pxs->ccr;
        unsigned long c, bursts = BYTE_TO_BURST(x->bytes, ccr);
        int off = 0;

        while (bursts) {
                c = bursts;
                off += _loop(dry_run, &buf[off], &c, pxs);
                bursts -= c;
        }

        return off;
}

static inline int _setup_xfer(unsigned dry_run, u8 buf[],
                const struct _xfer_spec *pxs)
{
        struct pl330_xfer *x = &pxs->desc->px;
        int off = 0;

        /* DMAMOV SAR, x->src_addr */
        off += _emit_MOV(dry_run, &buf[off], SAR, x->src_addr);
        /* DMAMOV DAR, x->dst_addr */
        off += _emit_MOV(dry_run, &buf[off], DAR, x->dst_addr);

        /* Setup Loop(s) */
        off += _setup_loops(dry_run, &buf[off], pxs);

        return off;
}

/*
 * A req is a sequence of one or more xfer units.
 * Returns the number of bytes taken to setup the MC for the req.
 */
static int _setup_req(unsigned dry_run, struct pl330_thread *thrd,
                unsigned index, struct _xfer_spec *pxs)
{
        struct _pl330_req *req = &thrd->req[index];
        struct pl330_xfer *x;
        u8 *buf = req->mc_cpu;
        int off = 0;

        PL330_DBGMC_START(req->mc_bus);

        /* DMAMOV CCR, ccr */
        off += _emit_MOV(dry_run, &buf[off], CCR, pxs->ccr);

        x = &pxs->desc->px;
        /* Error if xfer length is not aligned at burst size */
        if (x->bytes % (BRST_SIZE(pxs->ccr) * BRST_LEN(pxs->ccr)))
                return -EINVAL;

        off += _setup_xfer(dry_run, &buf[off], pxs);

        /* DMASEV peripheral/event */
        off += _emit_SEV(dry_run, &buf[off], thrd->ev);
        /* DMAEND */
        off += _emit_END(dry_run, &buf[off]);

        return off;
}

static inline u32 _prepare_ccr(const struct pl330_reqcfg *rqc)
{
        u32 ccr = 0;

        if (rqc->src_inc)
                ccr |= CC_SRCINC;

        if (rqc->dst_inc)
                ccr |= CC_DSTINC;

        /* We set same protection levels for Src and DST for now */
        if (rqc->privileged)
                ccr |= CC_SRCPRI | CC_DSTPRI;
        if (rqc->nonsecure)
                ccr |= CC_SRCNS | CC_DSTNS;
        if (rqc->insnaccess)
                ccr |= CC_SRCIA | CC_DSTIA;

        ccr |= (((rqc->brst_len - 1) & 0xf) << CC_SRCBRSTLEN_SHFT);
        ccr |= (((rqc->brst_len - 1) & 0xf) << CC_DSTBRSTLEN_SHFT);

        ccr |= (rqc->brst_size << CC_SRCBRSTSIZE_SHFT);
        ccr |= (rqc->brst_size << CC_DSTBRSTSIZE_SHFT);

        ccr |= (rqc->scctl << CC_SRCCCTRL_SHFT);
        ccr |= (rqc->dcctl << CC_DSTCCTRL_SHFT);

        ccr |= (rqc->swap << CC_SWAP_SHFT);

        return ccr;
}

/*
 * Submit a list of xfers after which the client wants notification.
 * Client is not notified after each xfer unit, just once after all
 * xfer units are done or some error occurs.
 */
static int pl330_submit_req(struct pl330_thread *thrd,
        struct dma_pl330_desc *desc)
{
        struct pl330_dmac *pl330 = thrd->dmac;
        struct _xfer_spec xs;
        unsigned long flags;
        unsigned idx;
        u32 ccr;
        int ret = 0;

        if (pl330->state == DYING
                || pl330->dmac_tbd.reset_chan & (1 << thrd->id)) {
                dev_info(thrd->dmac->ddma.dev, "%s:%d\n",
                        __func__, __LINE__);
                return -EAGAIN;
        }

        /* If request for non-existing peripheral */
        if (desc->rqtype != DMA_MEM_TO_MEM &&
            desc->peri >= pl330->pcfg.num_peri) {
                dev_info(thrd->dmac->ddma.dev,
                                "%s:%d Invalid peripheral(%u)!\n",
                                __func__, __LINE__, desc->peri);
                return -EINVAL;
        }

        spin_lock_irqsave(&pl330->lock, flags);

        if (_queue_full(thrd)) {
                ret = -EAGAIN;
                goto xfer_exit;
        }

        /* Prefer Secure Channel */
        if (!_manager_ns(thrd))
                desc->rqcfg.nonsecure = 0;
        else
                desc->rqcfg.nonsecure = 1;

        ccr = _prepare_ccr(&desc->rqcfg);

        idx = thrd->req[0].desc == NULL ? 0 : 1;

        xs.ccr = ccr;
        xs.desc = desc;

        /* First dry run to check if req is acceptable */
        ret = _setup_req(1, thrd, idx, &xs);
        if (ret < 0)
                goto xfer_exit;

        if (ret > pl330->mcbufsz / 2) {
                dev_info(pl330->ddma.dev, "%s:%d Try increasing mcbufsz (%i/%i)\n",
                                __func__, __LINE__, ret, pl330->mcbufsz / 2);
                ret = -ENOMEM;
                goto xfer_exit;
        }

        /* Hook the request */
        thrd->lstenq = idx;
        thrd->req[idx].desc = desc;
        _setup_req(0, thrd, idx, &xs);

        ret = 0;

xfer_exit:
        spin_unlock_irqrestore(&pl330->lock, flags);

        return ret;
}

static void dma_pl330_rqcb(struct dma_pl330_desc *desc, enum pl330_op_err err)
{
        struct dma_pl330_chan *pch;
        unsigned long flags;

        if (!desc)
                return;

        pch = desc->pchan;

        /* If desc aborted */
        if (!pch)
                return;

        spin_lock_irqsave(&pch->lock, flags);

        desc->status = DONE;

        spin_unlock_irqrestore(&pch->lock, flags);

        tasklet_schedule(&pch->task);
}

static void pl330_dotask(unsigned long data)
{
        struct pl330_dmac *pl330 = (struct pl330_dmac *) data;
        unsigned long flags;
        int i;

        spin_lock_irqsave(&pl330->lock, flags);

        /* The DMAC itself gone nuts */
        if (pl330->dmac_tbd.reset_dmac) {
                pl330->state = DYING;
                /* Reset the manager too */
                pl330->dmac_tbd.reset_mngr = true;
                /* Clear the reset flag */
                pl330->dmac_tbd.reset_dmac = false;
        }

        if (pl330->dmac_tbd.reset_mngr) {
                _stop(pl330->manager);
                /* Reset all channels */
                pl330->dmac_tbd.reset_chan = (1 << pl330->pcfg.num_chan) - 1;
                /* Clear the reset flag */
                pl330->dmac_tbd.reset_mngr = false;
        }

        for (i = 0; i < pl330->pcfg.num_chan; i++) {

                if (pl330->dmac_tbd.reset_chan & (1 << i)) {
                        struct pl330_thread *thrd = &pl330->channels[i];
                        void __iomem *regs = pl330->base;
                        enum pl330_op_err err;

                        _stop(thrd);

                        if (readl(regs + FSC) & (1 << thrd->id))
                                err = PL330_ERR_FAIL;
                        else
                                err = PL330_ERR_ABORT;

                        spin_unlock_irqrestore(&pl330->lock, flags);
                        dma_pl330_rqcb(thrd->req[1 - thrd->lstenq].desc, err);
                        dma_pl330_rqcb(thrd->req[thrd->lstenq].desc, err);
                        spin_lock_irqsave(&pl330->lock, flags);

                        thrd->req[0].desc = NULL;
                        thrd->req[1].desc = NULL;
                        thrd->req_running = -1;

                        /* Clear the reset flag */
                        pl330->dmac_tbd.reset_chan &= ~(1 << i);
                }
        }

        spin_unlock_irqrestore(&pl330->lock, flags);

        return;
}

/* Returns 1 if state was updated, 0 otherwise */
static int pl330_update(struct pl330_dmac *pl330)
{
        struct dma_pl330_desc *descdone, *tmp;
        unsigned long flags;
        void __iomem *regs;
        u32 val;
        int id, ev, ret = 0;

        regs = pl330->base;

        spin_lock_irqsave(&pl330->lock, flags);

        val = readl(regs + FSM) & 0x1;
        if (val)
                pl330->dmac_tbd.reset_mngr = true;
        else
                pl330->dmac_tbd.reset_mngr = false;

        val = readl(regs + FSC) & ((1 << pl330->pcfg.num_chan) - 1);
        pl330->dmac_tbd.reset_chan |= val;
        if (val) {
                int i = 0;
                while (i < pl330->pcfg.num_chan) {
                        if (val & (1 << i)) {
                                dev_info(pl330->ddma.dev,
                                        "Reset Channel-%d\t CS-%x FTC-%x\n",
                                                i, readl(regs + CS(i)),
                                                readl(regs + FTC(i)));
                                _stop(&pl330->channels[i]);
                        }
                        i++;
                }
        }

        /* Check which event happened i.e, thread notified */
        val = readl(regs + ES);
        if (pl330->pcfg.num_events < 32
                        && val & ~((1 << pl330->pcfg.num_events) - 1)) {
                pl330->dmac_tbd.reset_dmac = true;
                dev_err(pl330->ddma.dev, "%s:%d Unexpected!\n", __func__,
                        __LINE__);
                ret = 1;
                goto updt_exit;
        }

        for (ev = 0; ev < pl330->pcfg.num_events; ev++) {
                if (val & (1 << ev)) { /* Event occurred */
                        struct pl330_thread *thrd;
                        u32 inten = readl(regs + INTEN);
                        int active;

                        /* Clear the event */
                        if (inten & (1 << ev))
                                writel(1 << ev, regs + INTCLR);

                        ret = 1;

                        id = pl330->events[ev];

                        thrd = &pl330->channels[id];

                        active = thrd->req_running;
                        if (active == -1) /* Aborted */
                                continue;

                        /* Detach the req */
                        descdone = thrd->req[active].desc;
                        thrd->req[active].desc = NULL;

                        thrd->req_running = -1;

                        /* Get going again ASAP */
                        _start(thrd);

                        /* For now, just make a list of callbacks to be done */
                        list_add_tail(&descdone->rqd, &pl330->req_done);
                }
        }

        /* Now that we are in no hurry, do the callbacks */
        list_for_each_entry_safe(descdone, tmp, &pl330->req_done, rqd) {
                list_del(&descdone->rqd);
                spin_unlock_irqrestore(&pl330->lock, flags);
                dma_pl330_rqcb(descdone, PL330_ERR_NONE);
                spin_lock_irqsave(&pl330->lock, flags);
        }

updt_exit:
        spin_unlock_irqrestore(&pl330->lock, flags);

        if (pl330->dmac_tbd.reset_dmac
                        || pl330->dmac_tbd.reset_mngr
                        || pl330->dmac_tbd.reset_chan) {
                ret = 1;
                tasklet_schedule(&pl330->tasks);
        }

        return ret;
}

/* Reserve an event */
static inline int _alloc_event(struct pl330_thread *thrd)
{
        struct pl330_dmac *pl330 = thrd->dmac;
        int ev;

        for (ev = 0; ev < pl330->pcfg.num_events; ev++)
                if (pl330->events[ev] == -1) {
                        pl330->events[ev] = thrd->id;
                        return ev;
                }

        return -1;
}

static bool _chan_ns(const struct pl330_dmac *pl330, int i)
{
        return pl330->pcfg.irq_ns & (1 << i);
}

/* Upon success, returns IdentityToken for the
 * allocated channel, NULL otherwise.
 */
static struct pl330_thread *pl330_request_channel(struct pl330_dmac *pl330)
{
        struct pl330_thread *thrd = NULL;
        unsigned long flags;
        int chans, i;

        if (pl330->state == DYING)
                return NULL;

        chans = pl330->pcfg.num_chan;

        spin_lock_irqsave(&pl330->lock, flags);

        for (i = 0; i < chans; i++) {
                thrd = &pl330->channels[i];
                if ((thrd->free) && (!_manager_ns(thrd) ||
                                        _chan_ns(pl330, i))) {
                        thrd->ev = _alloc_event(thrd);
                        if (thrd->ev >= 0) {
                                thrd->free = false;
                                thrd->lstenq = 1;
                                thrd->req[0].desc = NULL;
                                thrd->req[1].desc = NULL;
                                thrd->req_running = -1;
                                break;
                        }
                }
                thrd = NULL;
        }

        spin_unlock_irqrestore(&pl330->lock, flags);

        return thrd;
}

/* Release an event */
static inline void _free_event(struct pl330_thread *thrd, int ev)
{
        struct pl330_dmac *pl330 = thrd->dmac;

        /* If the event is valid and was held by the thread */
        if (ev >= 0 && ev < pl330->pcfg.num_events
                        && pl330->events[ev] == thrd->id)
                pl330->events[ev] = -1;
}

static void pl330_release_channel(struct pl330_thread *thrd)
{
        struct pl330_dmac *pl330;
        unsigned long flags;

        if (!thrd || thrd->free)
                return;

        _stop(thrd);

        dma_pl330_rqcb(thrd->req[1 - thrd->lstenq].desc, PL330_ERR_ABORT);
        dma_pl330_rqcb(thrd->req[thrd->lstenq].desc, PL330_ERR_ABORT);

        pl330 = thrd->dmac;

        spin_lock_irqsave(&pl330->lock, flags);
        _free_event(thrd, thrd->ev);
        thrd->free = true;
        spin_unlock_irqrestore(&pl330->lock, flags);
}

/* Initialize the structure for PL330 configuration, that can be used
 * by the client driver the make best use of the DMAC
 */
static void read_dmac_config(struct pl330_dmac *pl330)
{
        void __iomem *regs = pl330->base;
        u32 val;

        val = readl(regs + CRD) >> CRD_DATA_WIDTH_SHIFT;
        val &= CRD_DATA_WIDTH_MASK;
        pl330->pcfg.data_bus_width = 8 * (1 << val);

        val = readl(regs + CRD) >> CRD_DATA_BUFF_SHIFT;
        val &= CRD_DATA_BUFF_MASK;
        pl330->pcfg.data_buf_dep = val + 1;

        val = readl(regs + CR0) >> CR0_NUM_CHANS_SHIFT;
        val &= CR0_NUM_CHANS_MASK;
        val += 1;
        pl330->pcfg.num_chan = val;

        val = readl(regs + CR0);
        if (val & CR0_PERIPH_REQ_SET) {
                val = (val >> CR0_NUM_PERIPH_SHIFT) & CR0_NUM_PERIPH_MASK;
                val += 1;
                pl330->pcfg.num_peri = val;
                pl330->pcfg.peri_ns = readl(regs + CR4);
        } else {
                pl330->pcfg.num_peri = 0;
        }

        val = readl(regs + CR0);
        if (val & CR0_BOOT_MAN_NS)
                pl330->pcfg.mode |= DMAC_MODE_NS;
        else
                pl330->pcfg.mode &= ~DMAC_MODE_NS;

        val = readl(regs + CR0) >> CR0_NUM_EVENTS_SHIFT;
        val &= CR0_NUM_EVENTS_MASK;
        val += 1;
        pl330->pcfg.num_events = val;

        pl330->pcfg.irq_ns = readl(regs + CR3);
}

static inline void _reset_thread(struct pl330_thread *thrd)
{
        struct pl330_dmac *pl330 = thrd->dmac;

        thrd->req[0].mc_cpu = pl330->mcode_cpu
                                + (thrd->id * pl330->mcbufsz);
        thrd->req[0].mc_bus = pl330->mcode_bus
                                + (thrd->id * pl330->mcbufsz);
        thrd->req[0].desc = NULL;

        thrd->req[1].mc_cpu = thrd->req[0].mc_cpu
                                + pl330->mcbufsz / 2;
        thrd->req[1].mc_bus = thrd->req[0].mc_bus
                                + pl330->mcbufsz / 2;
        thrd->req[1].desc = NULL;

        thrd->req_running = -1;
}

static int dmac_alloc_threads(struct pl330_dmac *pl330)
{
        int chans = pl330->pcfg.num_chan;
        struct pl330_thread *thrd;
        int i;

        /* Allocate 1 Manager and 'chans' Channel threads */
        pl330->channels = kzalloc((1 + chans) * sizeof(*thrd),
                                        GFP_KERNEL);
        if (!pl330->channels)
                return -ENOMEM;

        /* Init Channel threads */
        for (i = 0; i < chans; i++) {
                thrd = &pl330->channels[i];
                thrd->id = i;
                thrd->dmac = pl330;
                _reset_thread(thrd);
                thrd->free = true;
        }

        /* MANAGER is indexed at the end */
        thrd = &pl330->channels[chans];
        thrd->id = chans;
        thrd->dmac = pl330;
        thrd->free = false;
        pl330->manager = thrd;

        return 0;
}

static int dmac_alloc_resources(struct pl330_dmac *pl330)
{
        int chans = pl330->pcfg.num_chan;
        int ret;

        /*
         * Alloc MicroCode buffer for 'chans' Channel threads.
         * A channel's buffer offset is (Channel_Id * MCODE_BUFF_PERCHAN)
         */
        pl330->mcode_cpu = dma_alloc_coherent(pl330->ddma.dev,
                                chans * pl330->mcbufsz,
                                &pl330->mcode_bus, GFP_KERNEL);
        if (!pl330->mcode_cpu) {
                dev_err(pl330->ddma.dev, "%s:%d Can't allocate memory!\n",
                        __func__, __LINE__);
                return -ENOMEM;
        }

        ret = dmac_alloc_threads(pl330);
        if (ret) {
                dev_err(pl330->ddma.dev, "%s:%d Can't to create channels for DMAC!\n",
                        __func__, __LINE__);
                dma_free_coherent(pl330->ddma.dev,
                                chans * pl330->mcbufsz,
                                pl330->mcode_cpu, pl330->mcode_bus);
                return ret;
        }

        return 0;
}

static int pl330_add(struct pl330_dmac *pl330)
{
        void __iomem *regs;
        int i, ret;

        regs = pl330->base;

        /* Check if we can handle this DMAC */
        if ((pl330->pcfg.periph_id & 0xfffff) != PERIPH_ID_VAL) {
                dev_err(pl330->ddma.dev, "PERIPH_ID 0x%x !\n",
                        pl330->pcfg.periph_id);
                return -EINVAL;
        }

        /* Read the configuration of the DMAC */
        read_dmac_config(pl330);

        if (pl330->pcfg.num_events == 0) {
                dev_err(pl330->ddma.dev, "%s:%d Can't work without events!\n",
                        __func__, __LINE__);
                return -EINVAL;
        }

        spin_lock_init(&pl330->lock);

        INIT_LIST_HEAD(&pl330->req_done);

        /* Use default MC buffer size if not provided */
        if (!pl330->mcbufsz)
                pl330->mcbufsz = MCODE_BUFF_PER_REQ * 2;

        /* Mark all events as free */
        for (i = 0; i < pl330->pcfg.num_events; i++)
                pl330->events[i] = -1;

        /* Allocate resources needed by the DMAC */
        ret = dmac_alloc_resources(pl330);
        if (ret) {
                dev_err(pl330->ddma.dev, "Unable to create channels for DMAC\n");
                return ret;
        }

        tasklet_init(&pl330->tasks, pl330_dotask, (unsigned long) pl330);

        pl330->state = INIT;

        return 0;
}

static int dmac_free_threads(struct pl330_dmac *pl330)
{
        struct pl330_thread *thrd;
        int i;

        /* Release Channel threads */
        for (i = 0; i < pl330->pcfg.num_chan; i++) {
                thrd = &pl330->channels[i];
                pl330_release_channel(thrd);
        }

        /* Free memory */
        kfree(pl330->channels);

        return 0;
}

static void pl330_del(struct pl330_dmac *pl330)
{
        pl330->state = UNINIT;

        tasklet_kill(&pl330->tasks);

        /* Free DMAC resources */
        dmac_free_threads(pl330);

        dma_free_coherent(pl330->ddma.dev,
                pl330->pcfg.num_chan * pl330->mcbufsz, pl330->mcode_cpu,
                pl330->mcode_bus);
}

/* forward declaration */
static struct amba_driver pl330_driver;

static inline struct dma_pl330_chan *
to_pchan(struct dma_chan *ch)
{
        if (!ch)
                return NULL;

        return container_of(ch, struct dma_pl330_chan, chan);
}

static inline struct dma_pl330_desc *
to_desc(struct dma_async_tx_descriptor *tx)
{
        return container_of(tx, struct dma_pl330_desc, txd);
}

static inline void fill_queue(struct dma_pl330_chan *pch)
{
        struct dma_pl330_desc *desc;
        int ret;

        list_for_each_entry(desc, &pch->work_list, node) {

                /* If already submitted */
                if (desc->status == BUSY)
                        continue;

                ret = pl330_submit_req(pch->thread, desc);
                if (!ret) {
                        desc->status = BUSY;
                } else if (ret == -EAGAIN) {
                        /* QFull or DMAC Dying */
                        break;
                } else {
                        /* Unacceptable request */
                        desc->status = DONE;
                        dev_err(pch->dmac->ddma.dev, "%s:%d Bad Desc(%d)\n",
                                        __func__, __LINE__, desc->txd.cookie);
                        tasklet_schedule(&pch->task);
                }
        }
}

static void pl330_tasklet(unsigned long data)
{
        struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data;
        struct dma_pl330_desc *desc, *_dt;
        unsigned long flags;
        bool power_down = false;

        spin_lock_irqsave(&pch->lock, flags);

        /* Pick up ripe tomatoes */
        list_for_each_entry_safe(desc, _dt, &pch->work_list, node)
                if (desc->status == DONE) {
                        if (!pch->cyclic)
                                dma_cookie_complete(&desc->txd);
                        list_move_tail(&desc->node, &pch->completed_list);
                }

        /* Try to submit a req imm. next to the last completed cookie */
        fill_queue(pch);

        if (list_empty(&pch->work_list)) {
                spin_lock(&pch->thread->dmac->lock);
                _stop(pch->thread);
                spin_unlock(&pch->thread->dmac->lock);
                power_down = true;
        } else {
                /* Make sure the PL330 Channel thread is active */
                spin_lock(&pch->thread->dmac->lock);
                _start(pch->thread);

                spin_unlock(&pch->thread->dmac->lock);
        }

        while (!list_empty(&pch->completed_list)) {
                dma_async_tx_callback callback;
                void *callback_param;

                desc = list_first_entry(&pch->completed_list,
                                        struct dma_pl330_desc, node);

                callback = desc->txd.callback;
                callback_param = desc->txd.callback_param;

                if (pch->cyclic) {
                        desc->status = PREP;
                        list_move_tail(&desc->node, &pch->work_list);
                        if (power_down) {
                                spin_lock(&pch->thread->dmac->lock);
                                _start(pch->thread);
                                spin_unlock(&pch->thread->dmac->lock);
                                power_down = false;
                        }
                } else {
                        desc->status = FREE;
                        list_move_tail(&desc->node, &pch->dmac->desc_pool);
                }

                dma_descriptor_unmap(&desc->txd);

                if (callback) {
                        spin_unlock_irqrestore(&pch->lock, flags);
                        callback(callback_param);
                        spin_lock_irqsave(&pch->lock, flags);
                }
        }
        spin_unlock_irqrestore(&pch->lock, flags);

        /* If work list empty, power down */
        if (power_down) {
                pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
                pm_runtime_put_autosuspend(pch->dmac->ddma.dev);
        }
}

bool pl330_filter(struct dma_chan *chan, void *param)
{
        u8 *peri_id;

        if (chan->device->dev->driver != &pl330_driver.drv)
                return false;

        peri_id = chan->private;
        return *peri_id == (unsigned long)param;
}
EXPORT_SYMBOL(pl330_filter);

static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec,
                                                struct of_dma *ofdma)
{
        int count = dma_spec->args_count;
        struct pl330_dmac *pl330 = ofdma->of_dma_data;
        unsigned int chan_id;

        if (!pl330)
                return NULL;

        if (count != 1)
                return NULL;

        chan_id = dma_spec->args[0];
        if (chan_id >= pl330->num_peripherals)
                return NULL;

        return dma_get_slave_channel(&pl330->peripherals[chan_id].chan);
}

static int pl330_alloc_chan_resources(struct dma_chan *chan)
{
        struct dma_pl330_chan *pch = to_pchan(chan);
        struct pl330_dmac *pl330 = pch->dmac;
        unsigned long flags;

        spin_lock_irqsave(&pch->lock, flags);

        dma_cookie_init(chan);
        pch->cyclic = false;

        pch->thread = pl330_request_channel(pl330);
        if (!pch->thread) {
                spin_unlock_irqrestore(&pch->lock, flags);
                return -ENOMEM;
        }

        tasklet_init(&pch->task, pl330_tasklet, (unsigned long) pch);

        spin_unlock_irqrestore(&pch->lock, flags);

        return 1;
}

static int pl330_config(struct dma_chan *chan,
                        struct dma_slave_config *slave_config)
{
        struct dma_pl330_chan *pch = to_pchan(chan);

        if (slave_config->direction == DMA_MEM_TO_DEV) {
                if (slave_config->dst_addr)
                        pch->fifo_addr = slave_config->dst_addr;
                if (slave_config->dst_addr_width)
                        pch->burst_sz = __ffs(slave_config->dst_addr_width);
                if (slave_config->dst_maxburst)
                        pch->burst_len = slave_config->dst_maxburst;
        } else if (slave_config->direction == DMA_DEV_TO_MEM) {
                if (slave_config->src_addr)
                        pch->fifo_addr = slave_config->src_addr;
                if (slave_config->src_addr_width)
                        pch->burst_sz = __ffs(slave_config->src_addr_width);
                if (slave_config->src_maxburst)
                        pch->burst_len = slave_config->src_maxburst;
        }

        return 0;
}

static int pl330_terminate_all(struct dma_chan *chan)
{
        struct dma_pl330_chan *pch = to_pchan(chan);
        struct dma_pl330_desc *desc;
        unsigned long flags;
        struct pl330_dmac *pl330 = pch->dmac;
        LIST_HEAD(list);

        pm_runtime_get_sync(pl330->ddma.dev);
        spin_lock_irqsave(&pch->lock, flags);
        spin_lock(&pl330->lock);
        _stop(pch->thread);
        spin_unlock(&pl330->lock);

        pch->thread->req[0].desc = NULL;
        pch->thread->req[1].desc = NULL;
        pch->thread->req_running = -1;

        /* Mark all desc done */
        list_for_each_entry(desc, &pch->submitted_list, node) {
                desc->status = FREE;
                dma_cookie_complete(&desc->txd);
        }

        list_for_each_entry(desc, &pch->work_list , node) {
                desc->status = FREE;
                dma_cookie_complete(&desc->txd);
        }

        list_splice_tail_init(&pch->submitted_list, &pl330->desc_pool);
        list_splice_tail_init(&pch->work_list, &pl330->desc_pool);
        list_splice_tail_init(&pch->completed_list, &pl330->desc_pool);
        spin_unlock_irqrestore(&pch->lock, flags);
        pm_runtime_mark_last_busy(pl330->ddma.dev);
        pm_runtime_put_autosuspend(pl330->ddma.dev);

        return 0;
}

/*
 * We don't support DMA_RESUME command because of hardware
 * limitations, so after pausing the channel we cannot restore
 * it to active state. We have to terminate channel and setup
 * DMA transfer again. This pause feature was implemented to
 * allow safely read residue before channel termination.
 */
static int pl330_pause(struct dma_chan *chan)
{
        struct dma_pl330_chan *pch = to_pchan(chan);
        struct pl330_dmac *pl330 = pch->dmac;
        unsigned long flags;

        pm_runtime_get_sync(pl330->ddma.dev);
        spin_lock_irqsave(&pch->lock, flags);

        spin_lock(&pl330->lock);
        _stop(pch->thread);
        spin_unlock(&pl330->lock);

        spin_unlock_irqrestore(&pch->lock, flags);
        pm_runtime_mark_last_busy(pl330->ddma.dev);
        pm_runtime_put_autosuspend(pl330->ddma.dev);

        return 0;
}

static void pl330_free_chan_resources(struct dma_chan *chan)
{
        struct dma_pl330_chan *pch = to_pchan(chan);
        unsigned long flags;

        tasklet_kill(&pch->task);

        pm_runtime_get_sync(pch->dmac->ddma.dev);
        spin_lock_irqsave(&pch->lock, flags);

        pl330_release_channel(pch->thread);
        pch->thread = NULL;

        if (pch->cyclic)
                list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool);

        spin_unlock_irqrestore(&pch->lock, flags);
        pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
        pm_runtime_put_autosuspend(pch->dmac->ddma.dev);
}

static int pl330_get_current_xferred_count(struct dma_pl330_chan *pch,
                                           struct dma_pl330_desc *desc)
{
        struct pl330_thread *thrd = pch->thread;
        struct pl330_dmac *pl330 = pch->dmac;
        void __iomem *regs = thrd->dmac->base;
        u32 val, addr;

        pm_runtime_get_sync(pl330->ddma.dev);
        val = addr = 0;
        if (desc->rqcfg.src_inc) {
                val = readl(regs + SA(thrd->id));
                addr = desc->px.src_addr;
        } else {
                val = readl(regs + DA(thrd->id));
                addr = desc->px.dst_addr;
        }
        pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
        pm_runtime_put_autosuspend(pl330->ddma.dev);
        return val - addr;
}

static enum dma_status
pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
                 struct dma_tx_state *txstate)
{
        enum dma_status ret;
        unsigned long flags;
        struct dma_pl330_desc *desc, *running = NULL;
        struct dma_pl330_chan *pch = to_pchan(chan);
        unsigned int transferred, residual = 0;

        ret = dma_cookie_status(chan, cookie, txstate);

        if (!txstate)
                return ret;

        if (ret == DMA_COMPLETE)
                goto out;

        spin_lock_irqsave(&pch->lock, flags);

        if (pch->thread->req_running != -1)
                running = pch->thread->req[pch->thread->req_running].desc;

        /* Check in pending list */
        list_for_each_entry(desc, &pch->work_list, node) {
                if (desc->status == DONE)
                        transferred = desc->bytes_requested;
                else if (running && desc == running)
                        transferred =
                                pl330_get_current_xferred_count(pch, desc);
                else
                        transferred = 0;
                residual += desc->bytes_requested - transferred;
                if (desc->txd.cookie == cookie) {
                        switch (desc->status) {
                        case DONE:
                                ret = DMA_COMPLETE;
                                break;
                        case PREP:
                        case BUSY:
                                ret = DMA_IN_PROGRESS;
                                break;
                        default:
                                WARN_ON(1);
                        }
                        break;
                }
                if (desc->last)
                        residual = 0;
        }
        spin_unlock_irqrestore(&pch->lock, flags);

out:
        dma_set_residue(txstate, residual);

        return ret;
}

static void pl330_issue_pending(struct dma_chan *chan)
{
        struct dma_pl330_chan *pch = to_pchan(chan);
        unsigned long flags;

        spin_lock_irqsave(&pch->lock, flags);
        if (list_empty(&pch->work_list)) {
                /*
                 * Warn on nothing pending. Empty submitted_list may
                 * break our pm_runtime usage counter as it is
                 * updated on work_list emptiness status.
                 */
                WARN_ON(list_empty(&pch->submitted_list));
                pm_runtime_get_sync(pch->dmac->ddma.dev);
        }
        list_splice_tail_init(&pch->submitted_list, &pch->work_list);
        spin_unlock_irqrestore(&pch->lock, flags);

        pl330_tasklet((unsigned long)pch);
}

/*
 * We returned the last one of the circular list of descriptor(s)
 * from prep_xxx, so the argument to submit corresponds to the last
 * descriptor of the list.
 */
static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx)
{
        struct dma_pl330_desc *desc, *last = to_desc(tx);
        struct dma_pl330_chan *pch = to_pchan(tx->chan);
        dma_cookie_t cookie;
        unsigned long flags;

        spin_lock_irqsave(&pch->lock, flags);

        /* Assign cookies to all nodes */
        while (!list_empty(&last->node)) {
                desc = list_entry(last->node.next, struct dma_pl330_desc, node);
                if (pch->cyclic) {
                        desc->txd.callback = last->txd.callback;
                        desc->txd.callback_param = last->txd.callback_param;
                }
                desc->last = false;

                dma_cookie_assign(&desc->txd);

                list_move_tail(&desc->node, &pch->submitted_list);
        }

        last->last = true;
        cookie = dma_cookie_assign(&last->txd);
        list_add_tail(&last->node, &pch->submitted_list);
        spin_unlock_irqrestore(&pch->lock, flags);

        return cookie;
}

static inline void _init_desc(struct dma_pl330_desc *desc)
{
        desc->rqcfg.swap = SWAP_NO;
        desc->rqcfg.scctl = CCTRL0;
        desc->rqcfg.dcctl = CCTRL0;
        desc->txd.tx_submit = pl330_tx_submit;

        INIT_LIST_HEAD(&desc->node);
}

/* Returns the number of descriptors added to the DMAC pool */
static int add_desc(struct pl330_dmac *pl330, gfp_t flg, int count)
{
        struct dma_pl330_desc *desc;
        unsigned long flags;
        int i;

        desc = kcalloc(count, sizeof(*desc), flg);
        if (!desc)
                return 0;

        spin_lock_irqsave(&pl330->pool_lock, flags);

        for (i = 0; i < count; i++) {
                _init_desc(&desc[i]);
                list_add_tail(&desc[i].node, &pl330->desc_pool);
        }

        spin_unlock_irqrestore(&pl330->pool_lock, flags);

        return count;
}

static struct dma_pl330_desc *pluck_desc(struct pl330_dmac *pl330)
{
        struct dma_pl330_desc *desc = NULL;
        unsigned long flags;

        spin_lock_irqsave(&pl330->pool_lock, flags);

        if (!list_empty(&pl330->desc_pool)) {
                desc = list_entry(pl330->desc_pool.next,
                                struct dma_pl330_desc, node);

                list_del_init(&desc->node);

                desc->status = PREP;
                desc->txd.callback = NULL;
        }

        spin_unlock_irqrestore(&pl330->pool_lock, flags);

        return desc;
}

static struct dma_pl330_desc *pl330_get_desc(struct dma_pl330_chan *pch)
{
        struct pl330_dmac *pl330 = pch->dmac;
        u8 *peri_id = pch->chan.private;
        struct dma_pl330_desc *desc;

        /* Pluck one desc from the pool of DMAC */
        desc = pluck_desc(pl330);

        /* If the DMAC pool is empty, alloc new */
        if (!desc) {
                if (!add_desc(pl330, GFP_ATOMIC, 1))
                        return NULL;

                /* Try again */
                desc = pluck_desc(pl330);
                if (!desc) {
                        dev_err(pch->dmac->ddma.dev,
                                "%s:%d ALERT!\n", __func__, __LINE__);
                        return NULL;
                }
        }

        /* Initialize the descriptor */
        desc->pchan = pch;
        desc->txd.cookie = 0;
        async_tx_ack(&desc->txd);

        desc->peri = peri_id ? pch->chan.chan_id : 0;
        desc->rqcfg.pcfg = &pch->dmac->pcfg;

        dma_async_tx_descriptor_init(&desc->txd, &pch->chan);

        return desc;
}

static inline void fill_px(struct pl330_xfer *px,
                dma_addr_t dst, dma_addr_t src, size_t len)
{
        px->bytes = len;
        px->dst_addr = dst;
        px->src_addr = src;
}

static struct dma_pl330_desc *
__pl330_prep_dma_memcpy(struct dma_pl330_chan *pch, dma_addr_t dst,
                dma_addr_t src, size_t len)
{
        struct dma_pl330_desc *desc = pl330_get_desc(pch);

        if (!desc) {
                dev_err(pch->dmac->ddma.dev, "%s:%d Unable to fetch desc\n",
                        __func__, __LINE__);
                return NULL;
        }

        /*
         * Ideally we should lookout for reqs bigger than
         * those that can be programmed with 256 bytes of
         * MC buffer, but considering a req size is seldom
         * going to be word-unaligned and more than 200MB,
         * we take it easy.
         * Also, should the limit is reached we'd rather
         * have the platform increase MC buffer size than
         * complicating this API driver.
         */
        fill_px(&desc->px, dst, src, len);

        return desc;
}

/* Call after fixing burst size */
static inline int get_burst_len(struct dma_pl330_desc *desc, size_t len)
{
        struct dma_pl330_chan *pch = desc->pchan;
        struct pl330_dmac *pl330 = pch->dmac;
        int burst_len;

        burst_len = pl330->pcfg.data_bus_width / 8;
        burst_len *= pl330->pcfg.data_buf_dep / pl330->pcfg.num_chan;
        burst_len >>= desc->rqcfg.brst_size;

        /* src/dst_burst_len can't be more than 16 */
        if (burst_len > 16)
                burst_len = 16;

        while (burst_len > 1) {
                if (!(len % (burst_len << desc->rqcfg.brst_size)))
                        break;
                burst_len--;
        }

        return burst_len;
}

static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
                struct dma_chan *chan, dma_addr_t dma_addr, size_t len,
                size_t period_len, enum dma_transfer_direction direction,
                unsigned long flags)
{
        struct dma_pl330_desc *desc = NULL, *first = NULL;
        struct dma_pl330_chan *pch = to_pchan(chan);
        struct pl330_dmac *pl330 = pch->dmac;
        unsigned int i;
        dma_addr_t dst;
        dma_addr_t src;

        if (len % period_len != 0)
                return NULL;

        if (!is_slave_direction(direction)) {
                dev_err(pch->dmac->ddma.dev, "%s:%d Invalid dma direction\n",
                __func__, __LINE__);
                return NULL;
        }

        for (i = 0; i < len / period_len; i++) {
                desc = pl330_get_desc(pch);
                if (!desc) {
                        dev_err(pch->dmac->ddma.dev, "%s:%d Unable to fetch desc\n",
                                __func__, __LINE__);

                        if (!first)
                                return NULL;

                        spin_lock_irqsave(&pl330->pool_lock, flags);

                        while (!list_empty(&first->node)) {
                                desc = list_entry(first->node.next,
                                                struct dma_pl330_desc, node);
                                list_move_tail(&desc->node, &pl330->desc_pool);
                        }

                        list_move_tail(&first->node, &pl330->desc_pool);

                        spin_unlock_irqrestore(&pl330->pool_lock, flags);

                        return NULL;
                }

                switch (direction) {
                case DMA_MEM_TO_DEV:
                        desc->rqcfg.src_inc = 1;
                        desc->rqcfg.dst_inc = 0;
                        src = dma_addr;
                        dst = pch->fifo_addr;
                        break;
                case DMA_DEV_TO_MEM:
                        desc->rqcfg.src_inc = 0;
                        desc->rqcfg.dst_inc = 1;
                        src = pch->fifo_addr;
                        dst = dma_addr;
                        break;
                default:
                        break;
                }

                desc->rqtype = direction;
                desc->rqcfg.brst_size = pch->burst_sz;
                desc->rqcfg.brst_len = 1;
                desc->bytes_requested = period_len;
                fill_px(&desc->px, dst, src, period_len);

                if (!first)
                        first = desc;
                else
                        list_add_tail(&desc->node, &first->node);

                dma_addr += period_len;
        }

        if (!desc)
                return NULL;

        pch->cyclic = true;
        desc->txd.flags = flags;

        return &desc->txd;
}

static struct dma_async_tx_descriptor *
pl330_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst,
                dma_addr_t src, size_t len, unsigned long flags)
{
        struct dma_pl330_desc *desc;
        struct dma_pl330_chan *pch = to_pchan(chan);
        struct pl330_dmac *pl330;
        int burst;

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

        pl330 = pch->dmac;

        desc = __pl330_prep_dma_memcpy(pch, dst, src, len);
        if (!desc)
                return NULL;

        desc->rqcfg.src_inc = 1;
        desc->rqcfg.dst_inc = 1;
        desc->rqtype = DMA_MEM_TO_MEM;

        /* Select max possible burst size */
        burst = pl330->pcfg.data_bus_width / 8;

        /*
         * Make sure we use a burst size that aligns with all the memcpy
         * parameters because our DMA programming algorithm doesn't cope with
         * transfers which straddle an entry in the DMA device's MFIFO.
         */
        while ((src | dst | len) & (burst - 1))
                burst /= 2;

        desc->rqcfg.brst_size = 0;
        while (burst != (1 << desc->rqcfg.brst_size))
                desc->rqcfg.brst_size++;

        /*
         * If burst size is smaller than bus width then make sure we only
         * transfer one at a time to avoid a burst stradling an MFIFO entry.
         */
        if (desc->rqcfg.brst_size * 8 < pl330->pcfg.data_bus_width)
                desc->rqcfg.brst_len = 1;

        desc->rqcfg.brst_len = get_burst_len(desc, len);
        desc->bytes_requested = len;

        desc->txd.flags = flags;

        return &desc->txd;
}

static void __pl330_giveback_desc(struct pl330_dmac *pl330,
                                  struct dma_pl330_desc *first)
{
        unsigned long flags;
        struct dma_pl330_desc *desc;

        if (!first)
                return;

        spin_lock_irqsave(&pl330->pool_lock, flags);

        while (!list_empty(&first->node)) {
                desc = list_entry(first->node.next,
                                struct dma_pl330_desc, node);
                list_move_tail(&desc->node, &pl330->desc_pool);
        }

        list_move_tail(&first->node, &pl330->desc_pool);

        spin_unlock_irqrestore(&pl330->pool_lock, flags);
}

static struct dma_async_tx_descriptor *
pl330_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
                unsigned int sg_len, enum dma_transfer_direction direction,
                unsigned long flg, void *context)
{
        struct dma_pl330_desc *first, *desc = NULL;
        struct dma_pl330_chan *pch = to_pchan(chan);
        struct scatterlist *sg;
        int i;
        dma_addr_t addr;

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

        addr = pch->fifo_addr;

        first = NULL;

        for_each_sg(sgl, sg, sg_len, i) {

                desc = pl330_get_desc(pch);
                if (!desc) {
                        struct pl330_dmac *pl330 = pch->dmac;

                        dev_err(pch->dmac->ddma.dev,
                                "%s:%d Unable to fetch desc\n",
                                __func__, __LINE__);
                        __pl330_giveback_desc(pl330, first);

                        return NULL;
                }

                if (!first)
                        first = desc;
                else
                        list_add_tail(&desc->node, &first->node);

                if (direction == DMA_MEM_TO_DEV) {
                        desc->rqcfg.src_inc = 1;
                        desc->rqcfg.dst_inc = 0;
                        fill_px(&desc->px,
                                addr, sg_dma_address(sg), sg_dma_len(sg));
                } else {
                        desc->rqcfg.src_inc = 0;
                        desc->rqcfg.dst_inc = 1;
                        fill_px(&desc->px,
                                sg_dma_address(sg), addr, sg_dma_len(sg));
                }

                desc->rqcfg.brst_size = pch->burst_sz;
                desc->rqcfg.brst_len = 1;
                desc->rqtype = direction;
                desc->bytes_requested = sg_dma_len(sg);
        }

        /* Return the last desc in the chain */
        desc->txd.flags = flg;
        return &desc->txd;
}

static irqreturn_t pl330_irq_handler(int irq, void *data)
{
        if (pl330_update(data))
                return IRQ_HANDLED;
        else
                return IRQ_NONE;
}

#define PL330_DMA_BUSWIDTHS \
        BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
        BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
        BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
        BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
        BIT(DMA_SLAVE_BUSWIDTH_8_BYTES)

/*
 * Runtime PM callbacks are provided by amba/bus.c driver.
 *
 * It is assumed here that IRQ safe runtime PM is chosen in probe and amba
 * bus driver will only disable/enable the clock in runtime PM callbacks.
 */
static int __maybe_unused pl330_suspend(struct device *dev)
{
        struct amba_device *pcdev = to_amba_device(dev);

        pm_runtime_disable(dev);

        if (!pm_runtime_status_suspended(dev)) {
                /* amba did not disable the clock */
                amba_pclk_disable(pcdev);
        }
        amba_pclk_unprepare(pcdev);

        return 0;
}

static int __maybe_unused pl330_resume(struct device *dev)
{
        struct amba_device *pcdev = to_amba_device(dev);
        int ret;

        ret = amba_pclk_prepare(pcdev);
        if (ret)
                return ret;

        if (!pm_runtime_status_suspended(dev))
                ret = amba_pclk_enable(pcdev);

        pm_runtime_enable(dev);

        return ret;
}

static SIMPLE_DEV_PM_OPS(pl330_pm, pl330_suspend, pl330_resume);

static int
pl330_probe(struct amba_device *adev, const struct amba_id *id)
{
        struct dma_pl330_platdata *pdat;
        struct pl330_config *pcfg;
        struct pl330_dmac *pl330;
        struct dma_pl330_chan *pch, *_p;
        struct dma_device *pd;
        struct resource *res;
        int i, ret, irq;
        int num_chan;

        pdat = dev_get_platdata(&adev->dev);

        ret = dma_set_mask_and_coherent(&adev->dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        /* Allocate a new DMAC and its Channels */
        pl330 = devm_kzalloc(&adev->dev, sizeof(*pl330), GFP_KERNEL);
        if (!pl330) {
                dev_err(&adev->dev, "unable to allocate mem\n");
                return -ENOMEM;
        }

        pd = &pl330->ddma;
        pd->dev = &adev->dev;

        pl330->mcbufsz = pdat ? pdat->mcbuf_sz : 0;

        res = &adev->res;
        pl330->base = devm_ioremap_resource(&adev->dev, res);
        if (IS_ERR(pl330->base))
                return PTR_ERR(pl330->base);

        amba_set_drvdata(adev, pl330);

        for (i = 0; i < AMBA_NR_IRQS; i++) {
                irq = adev->irq[i];
                if (irq) {
                        ret = devm_request_irq(&adev->dev, irq,
                                               pl330_irq_handler, 0,
                                               dev_name(&adev->dev), pl330);
                        if (ret)
                                return ret;
                } else {
                        break;
                }
        }

        pcfg = &pl330->pcfg;

        pcfg->periph_id = adev->periphid;
        ret = pl330_add(pl330);
        if (ret)
                return ret;

        INIT_LIST_HEAD(&pl330->desc_pool);
        spin_lock_init(&pl330->pool_lock);

        /* Create a descriptor pool of default size */
        if (!add_desc(pl330, GFP_KERNEL, NR_DEFAULT_DESC))
                dev_warn(&adev->dev, "unable to allocate desc\n");

        INIT_LIST_HEAD(&pd->channels);

        /* Initialize channel parameters */
        if (pdat)
                num_chan = max_t(int, pdat->nr_valid_peri, pcfg->num_chan);
        else
                num_chan = max_t(int, pcfg->num_peri, pcfg->num_chan);

        pl330->num_peripherals = num_chan;

        pl330->peripherals = kzalloc(num_chan * sizeof(*pch), GFP_KERNEL);
        if (!pl330->peripherals) {
                ret = -ENOMEM;
                dev_err(&adev->dev, "unable to allocate pl330->peripherals\n");
                goto probe_err2;
        }

        for (i = 0; i < num_chan; i++) {
                pch = &pl330->peripherals[i];
                if (!adev->dev.of_node)
                        pch->chan.private = pdat ? &pdat->peri_id[i] : NULL;
                else
                        pch->chan.private = adev->dev.of_node;

                INIT_LIST_HEAD(&pch->submitted_list);
                INIT_LIST_HEAD(&pch->work_list);
                INIT_LIST_HEAD(&pch->completed_list);
                spin_lock_init(&pch->lock);
                pch->thread = NULL;
                pch->chan.device = pd;
                pch->dmac = pl330;

                /* Add the channel to the DMAC list */
                list_add_tail(&pch->chan.device_node, &pd->channels);
        }

        if (pdat) {
                pd->cap_mask = pdat->cap_mask;
        } else {
                dma_cap_set(DMA_MEMCPY, pd->cap_mask);
                if (pcfg->num_peri) {
                        dma_cap_set(DMA_SLAVE, pd->cap_mask);
                        dma_cap_set(DMA_CYCLIC, pd->cap_mask);
                        dma_cap_set(DMA_PRIVATE, pd->cap_mask);
                }
        }

        pd->device_alloc_chan_resources = pl330_alloc_chan_resources;
        pd->device_free_chan_resources = pl330_free_chan_resources;
        pd->device_prep_dma_memcpy = pl330_prep_dma_memcpy;
        pd->device_prep_dma_cyclic = pl330_prep_dma_cyclic;
        pd->device_tx_status = pl330_tx_status;
        pd->device_prep_slave_sg = pl330_prep_slave_sg;
        pd->device_config = pl330_config;
        pd->device_pause = pl330_pause;
        pd->device_terminate_all = pl330_terminate_all;
        pd->device_issue_pending = pl330_issue_pending;
        pd->src_addr_widths = PL330_DMA_BUSWIDTHS;
        pd->dst_addr_widths = PL330_DMA_BUSWIDTHS;
        pd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
        pd->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;

        ret = dma_async_device_register(pd);
        if (ret) {
                dev_err(&adev->dev, "unable to register DMAC\n");
                goto probe_err3;
        }

        if (adev->dev.of_node) {
                ret = of_dma_controller_register(adev->dev.of_node,
                                         of_dma_pl330_xlate, pl330);
                if (ret) {
                        dev_err(&adev->dev,
                        "unable to register DMA to the generic DT DMA helpers\n");
                }
        }

        adev->dev.dma_parms = &pl330->dma_parms;

        /*
         * This is the limit for transfers with a buswidth of 1, larger
         * buswidths will have larger limits.
         */
        ret = dma_set_max_seg_size(&adev->dev, 1900800);
        if (ret)
                dev_err(&adev->dev, "unable to set the seg size\n");


        dev_info(&adev->dev,
                "Loaded driver for PL330 DMAC-%x\n", adev->periphid);
        dev_info(&adev->dev,
                "\tDBUFF-%ux%ubytes Num_Chans-%u Num_Peri-%u Num_Events-%u\n",
                pcfg->data_buf_dep, pcfg->data_bus_width / 8, pcfg->num_chan,
                pcfg->num_peri, pcfg->num_events);

        pm_runtime_irq_safe(&adev->dev);
        pm_runtime_use_autosuspend(&adev->dev);
        pm_runtime_set_autosuspend_delay(&adev->dev, PL330_AUTOSUSPEND_DELAY);
        pm_runtime_mark_last_busy(&adev->dev);
        pm_runtime_put_autosuspend(&adev->dev);

        return 0;
probe_err3:
        /* Idle the DMAC */
        list_for_each_entry_safe(pch, _p, &pl330->ddma.channels,
                        chan.device_node) {

                /* Remove the channel */
                list_del(&pch->chan.device_node);

                /* Flush the channel */
                if (pch->thread) {
                        pl330_terminate_all(&pch->chan);
                        pl330_free_chan_resources(&pch->chan);
                }
        }
probe_err2:
        pl330_del(pl330);

        return ret;
}

static int pl330_remove(struct amba_device *adev)
{
        struct pl330_dmac *pl330 = amba_get_drvdata(adev);
        struct dma_pl330_chan *pch, *_p;

        pm_runtime_get_noresume(pl330->ddma.dev);

        if (adev->dev.of_node)
                of_dma_controller_free(adev->dev.of_node);

        dma_async_device_unregister(&pl330->ddma);

        /* Idle the DMAC */
        list_for_each_entry_safe(pch, _p, &pl330->ddma.channels,
                        chan.device_node) {

                /* Remove the channel */
                list_del(&pch->chan.device_node);

                /* Flush the channel */
                if (pch->thread) {
                        pl330_terminate_all(&pch->chan);
                        pl330_free_chan_resources(&pch->chan);
                }
        }

        pl330_del(pl330);

        return 0;
}

static struct amba_id pl330_ids[] = {
        {
                .id     = 0x00041330,
                .mask   = 0x000fffff,
        },
        { 0, 0 },
};

MODULE_DEVICE_TABLE(amba, pl330_ids);

static struct amba_driver pl330_driver = {