/*
 * drivers/dma/fsl-edma.c
 *
 * Copyright 2013-2014 Freescale Semiconductor, Inc.
 *
 * Driver for the Freescale eDMA engine with flexible channel multiplexing
 * capability for DMA request sources. The eDMA block can be found on some
 * Vybrid and Layerscape SoCs.
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_dma.h>

#include "virt-dma.h"

#define EDMA_CR                 0x00
#define EDMA_ES                 0x04
#define EDMA_ERQ                0x0C
#define EDMA_EEI                0x14
#define EDMA_SERQ               0x1B
#define EDMA_CERQ               0x1A
#define EDMA_SEEI               0x19
#define EDMA_CEEI               0x18
#define EDMA_CINT               0x1F
#define EDMA_CERR               0x1E
#define EDMA_SSRT               0x1D
#define EDMA_CDNE               0x1C
#define EDMA_INTR               0x24
#define EDMA_ERR                0x2C

#define EDMA_TCD_SADDR(x)       (0x1000 + 32 * (x))
#define EDMA_TCD_SOFF(x)        (0x1004 + 32 * (x))
#define EDMA_TCD_ATTR(x)        (0x1006 + 32 * (x))
#define EDMA_TCD_NBYTES(x)      (0x1008 + 32 * (x))
#define EDMA_TCD_SLAST(x)       (0x100C + 32 * (x))
#define EDMA_TCD_DADDR(x)       (0x1010 + 32 * (x))
#define EDMA_TCD_DOFF(x)        (0x1014 + 32 * (x))
#define EDMA_TCD_CITER_ELINK(x) (0x1016 + 32 * (x))
#define EDMA_TCD_CITER(x)       (0x1016 + 32 * (x))
#define EDMA_TCD_DLAST_SGA(x)   (0x1018 + 32 * (x))
#define EDMA_TCD_CSR(x)         (0x101C + 32 * (x))
#define EDMA_TCD_BITER_ELINK(x) (0x101E + 32 * (x))
#define EDMA_TCD_BITER(x)       (0x101E + 32 * (x))

#define EDMA_CR_EDBG            BIT(1)
#define EDMA_CR_ERCA            BIT(2)
#define EDMA_CR_ERGA            BIT(3)
#define EDMA_CR_HOE             BIT(4)
#define EDMA_CR_HALT            BIT(5)
#define EDMA_CR_CLM             BIT(6)
#define EDMA_CR_EMLM            BIT(7)
#define EDMA_CR_ECX             BIT(16)
#define EDMA_CR_CX              BIT(17)

#define EDMA_SEEI_SEEI(x)       ((x) & 0x1F)
#define EDMA_CEEI_CEEI(x)       ((x) & 0x1F)
#define EDMA_CINT_CINT(x)       ((x) & 0x1F)
#define EDMA_CERR_CERR(x)       ((x) & 0x1F)

#define EDMA_TCD_ATTR_DSIZE(x)          (((x) & 0x0007))
#define EDMA_TCD_ATTR_DMOD(x)           (((x) & 0x001F) << 3)
#define EDMA_TCD_ATTR_SSIZE(x)          (((x) & 0x0007) << 8)
#define EDMA_TCD_ATTR_SMOD(x)           (((x) & 0x001F) << 11)
#define EDMA_TCD_ATTR_SSIZE_8BIT        (0x0000)
#define EDMA_TCD_ATTR_SSIZE_16BIT       (0x0100)
#define EDMA_TCD_ATTR_SSIZE_32BIT       (0x0200)
#define EDMA_TCD_ATTR_SSIZE_64BIT       (0x0300)
#define EDMA_TCD_ATTR_SSIZE_32BYTE      (0x0500)
#define EDMA_TCD_ATTR_DSIZE_8BIT        (0x0000)
#define EDMA_TCD_ATTR_DSIZE_16BIT       (0x0001)
#define EDMA_TCD_ATTR_DSIZE_32BIT       (0x0002)
#define EDMA_TCD_ATTR_DSIZE_64BIT       (0x0003)
#define EDMA_TCD_ATTR_DSIZE_32BYTE      (0x0005)

#define EDMA_TCD_SOFF_SOFF(x)           (x)
#define EDMA_TCD_NBYTES_NBYTES(x)       (x)
#define EDMA_TCD_SLAST_SLAST(x)         (x)
#define EDMA_TCD_DADDR_DADDR(x)         (x)
#define EDMA_TCD_CITER_CITER(x)         ((x) & 0x7FFF)
#define EDMA_TCD_DOFF_DOFF(x)           (x)
#define EDMA_TCD_DLAST_SGA_DLAST_SGA(x) (x)
#define EDMA_TCD_BITER_BITER(x)         ((x) & 0x7FFF)

#define EDMA_TCD_CSR_START              BIT(0)
#define EDMA_TCD_CSR_INT_MAJOR          BIT(1)
#define EDMA_TCD_CSR_INT_HALF           BIT(2)
#define EDMA_TCD_CSR_D_REQ              BIT(3)
#define EDMA_TCD_CSR_E_SG               BIT(4)
#define EDMA_TCD_CSR_E_LINK             BIT(5)
#define EDMA_TCD_CSR_ACTIVE             BIT(6)
#define EDMA_TCD_CSR_DONE               BIT(7)

#define EDMAMUX_CHCFG_DIS               0x0
#define EDMAMUX_CHCFG_ENBL              0x80
#define EDMAMUX_CHCFG_SOURCE(n)         ((n) & 0x3F)

#define DMAMUX_NR       2

#define FSL_EDMA_BUSWIDTHS      BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
                                BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
                                BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
                                BIT(DMA_SLAVE_BUSWIDTH_8_BYTES)
enum fsl_edma_pm_state {
        RUNNING = 0,
        SUSPENDED,
};

struct fsl_edma_hw_tcd {
        __le32  saddr;
        __le16  soff;
        __le16  attr;
        __le32  nbytes;
        __le32  slast;
        __le32  daddr;
        __le16  doff;
        __le16  citer;
        __le32  dlast_sga;
        __le16  csr;
        __le16  biter;
};

struct fsl_edma_sw_tcd {
        dma_addr_t                      ptcd;
        struct fsl_edma_hw_tcd          *vtcd;
};

struct fsl_edma_slave_config {
        enum dma_transfer_direction     dir;
        enum dma_slave_buswidth         addr_width;
        u32                             dev_addr;
        u32                             burst;
        u32                             attr;
};

struct fsl_edma_chan {
        struct virt_dma_chan            vchan;
        enum dma_status                 status;
        enum fsl_edma_pm_state          pm_state;
        bool                            idle;
        u32                             slave_id;
        struct fsl_edma_engine          *edma;
        struct fsl_edma_desc            *edesc;
        struct fsl_edma_slave_config    fsc;
        struct dma_pool                 *tcd_pool;
};

struct fsl_edma_desc {
        struct virt_dma_desc            vdesc;
        struct fsl_edma_chan            *echan;
        bool                            iscyclic;
        unsigned int                    n_tcds;
        struct fsl_edma_sw_tcd          tcd[];
};

struct fsl_edma_engine {
        struct dma_device       dma_dev;
        void __iomem            *membase;
        void __iomem            *muxbase[DMAMUX_NR];
        struct clk              *muxclk[DMAMUX_NR];
        struct mutex            fsl_edma_mutex;
        u32                     n_chans;
        int                     txirq;
        int                     errirq;
        bool                    big_endian;
        struct fsl_edma_chan    chans[];
};

/*
 * R/W functions for big- or little-endian registers:
 * The eDMA controller's endian is independent of the CPU core's endian.
 * For the big-endian IP module, the offset for 8-bit or 16-bit registers
 * should also be swapped opposite to that in little-endian IP.
 */

static u32 edma_readl(struct fsl_edma_engine *edma, void __iomem *addr)
{
        if (edma->big_endian)
                return ioread32be(addr);
        else
                return ioread32(addr);
}

static void edma_writeb(struct fsl_edma_engine *edma, u8 val, void __iomem *addr)
{
        /* swap the reg offset for these in big-endian mode */
        if (edma->big_endian)
                iowrite8(val, (void __iomem *)((unsigned long)addr ^ 0x3));
        else
                iowrite8(val, addr);
}

static void edma_writew(struct fsl_edma_engine *edma, u16 val, void __iomem *addr)
{
        /* swap the reg offset for these in big-endian mode */
        if (edma->big_endian)
                iowrite16be(val, (void __iomem *)((unsigned long)addr ^ 0x2));
        else
                iowrite16(val, addr);
}

static void edma_writel(struct fsl_edma_engine *edma, u32 val, void __iomem *addr)
{
        if (edma->big_endian)
                iowrite32be(val, addr);
        else
                iowrite32(val, addr);
}

static struct fsl_edma_chan *to_fsl_edma_chan(struct dma_chan *chan)
{
        return container_of(chan, struct fsl_edma_chan, vchan.chan);
}

static struct fsl_edma_desc *to_fsl_edma_desc(struct virt_dma_desc *vd)
{
        return container_of(vd, struct fsl_edma_desc, vdesc);
}

static void fsl_edma_enable_request(struct fsl_edma_chan *fsl_chan)
{
        void __iomem *addr = fsl_chan->edma->membase;
        u32 ch = fsl_chan->vchan.chan.chan_id;

        edma_writeb(fsl_chan->edma, EDMA_SEEI_SEEI(ch), addr + EDMA_SEEI);
        edma_writeb(fsl_chan->edma, ch, addr + EDMA_SERQ);
}

static void fsl_edma_disable_request(struct fsl_edma_chan *fsl_chan)
{
        void __iomem *addr = fsl_chan->edma->membase;
        u32 ch = fsl_chan->vchan.chan.chan_id;

        edma_writeb(fsl_chan->edma, ch, addr + EDMA_CERQ);
        edma_writeb(fsl_chan->edma, EDMA_CEEI_CEEI(ch), addr + EDMA_CEEI);
}

static void fsl_edma_chan_mux(struct fsl_edma_chan *fsl_chan,
                        unsigned int slot, bool enable)
{
        u32 ch = fsl_chan->vchan.chan.chan_id;
        void __iomem *muxaddr;
        unsigned chans_per_mux, ch_off;

        chans_per_mux = fsl_chan->edma->n_chans / DMAMUX_NR;
        ch_off = fsl_chan->vchan.chan.chan_id % chans_per_mux;
        muxaddr = fsl_chan->edma->muxbase[ch / chans_per_mux];
        slot = EDMAMUX_CHCFG_SOURCE(slot);

        if (enable)
                iowrite8(EDMAMUX_CHCFG_ENBL | slot, muxaddr + ch_off);
        else
                iowrite8(EDMAMUX_CHCFG_DIS, muxaddr + ch_off);
}

static unsigned int fsl_edma_get_tcd_attr(enum dma_slave_buswidth addr_width)
{
        switch (addr_width) {
        case 1:
                return EDMA_TCD_ATTR_SSIZE_8BIT | EDMA_TCD_ATTR_DSIZE_8BIT;
        case 2:
                return EDMA_TCD_ATTR_SSIZE_16BIT | EDMA_TCD_ATTR_DSIZE_16BIT;
        case 4:
                return EDMA_TCD_ATTR_SSIZE_32BIT | EDMA_TCD_ATTR_DSIZE_32BIT;
        case 8:
                return EDMA_TCD_ATTR_SSIZE_64BIT | EDMA_TCD_ATTR_DSIZE_64BIT;
        default:
                return EDMA_TCD_ATTR_SSIZE_32BIT | EDMA_TCD_ATTR_DSIZE_32BIT;
        }
}

static void fsl_edma_free_desc(struct virt_dma_desc *vdesc)
{
        struct fsl_edma_desc *fsl_desc;
        int i;

        fsl_desc = to_fsl_edma_desc(vdesc);
        for (i = 0; i < fsl_desc->n_tcds; i++)
                dma_pool_free(fsl_desc->echan->tcd_pool, fsl_desc->tcd[i].vtcd,
                              fsl_desc->tcd[i].ptcd);
        kfree(fsl_desc);
}

static int fsl_edma_terminate_all(struct dma_chan *chan)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        unsigned long flags;
        LIST_HEAD(head);

        spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
        fsl_edma_disable_request(fsl_chan);
        fsl_chan->edesc = NULL;
        fsl_chan->idle = true;
        vchan_get_all_descriptors(&fsl_chan->vchan, &head);
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        vchan_dma_desc_free_list(&fsl_chan->vchan, &head);
        return 0;
}

static int fsl_edma_pause(struct dma_chan *chan)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        unsigned long flags;

        spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
        if (fsl_chan->edesc) {
                fsl_edma_disable_request(fsl_chan);
                fsl_chan->status = DMA_PAUSED;
                fsl_chan->idle = true;
        }
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        return 0;
}

static int fsl_edma_resume(struct dma_chan *chan)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        unsigned long flags;

        spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
        if (fsl_chan->edesc) {
                fsl_edma_enable_request(fsl_chan);
                fsl_chan->status = DMA_IN_PROGRESS;
                fsl_chan->idle = false;
        }
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        return 0;
}

static int fsl_edma_slave_config(struct dma_chan *chan,
                                 struct dma_slave_config *cfg)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);

        fsl_chan->fsc.dir = cfg->direction;
        if (cfg->direction == DMA_DEV_TO_MEM) {
                fsl_chan->fsc.dev_addr = cfg->src_addr;
                fsl_chan->fsc.addr_width = cfg->src_addr_width;
                fsl_chan->fsc.burst = cfg->src_maxburst;
                fsl_chan->fsc.attr = fsl_edma_get_tcd_attr(cfg->src_addr_width);
        } else if (cfg->direction == DMA_MEM_TO_DEV) {
                fsl_chan->fsc.dev_addr = cfg->dst_addr;
                fsl_chan->fsc.addr_width = cfg->dst_addr_width;
                fsl_chan->fsc.burst = cfg->dst_maxburst;
                fsl_chan->fsc.attr = fsl_edma_get_tcd_attr(cfg->dst_addr_width);
        } else {
                        return -EINVAL;
        }
        return 0;
}

static size_t fsl_edma_desc_residue(struct fsl_edma_chan *fsl_chan,
                struct virt_dma_desc *vdesc, bool in_progress)
{
        struct fsl_edma_desc *edesc = fsl_chan->edesc;
        void __iomem *addr = fsl_chan->edma->membase;
        u32 ch = fsl_chan->vchan.chan.chan_id;
        enum dma_transfer_direction dir = fsl_chan->fsc.dir;
        dma_addr_t cur_addr, dma_addr;
        size_t len, size;
        int i;

        /* calculate the total size in this desc */
        for (len = i = 0; i < fsl_chan->edesc->n_tcds; i++)
                len += le32_to_cpu(edesc->tcd[i].vtcd->nbytes)
                        * le16_to_cpu(edesc->tcd[i].vtcd->biter);

        if (!in_progress)
                return len;

        if (dir == DMA_MEM_TO_DEV)
                cur_addr = edma_readl(fsl_chan->edma, addr + EDMA_TCD_SADDR(ch));
        else
                cur_addr = edma_readl(fsl_chan->edma, addr + EDMA_TCD_DADDR(ch));

        /* figure out the finished and calculate the residue */
        for (i = 0; i < fsl_chan->edesc->n_tcds; i++) {
                size = le32_to_cpu(edesc->tcd[i].vtcd->nbytes)
                        * le16_to_cpu(edesc->tcd[i].vtcd->biter);
                if (dir == DMA_MEM_TO_DEV)
                        dma_addr = le32_to_cpu(edesc->tcd[i].vtcd->saddr);
                else
                        dma_addr = le32_to_cpu(edesc->tcd[i].vtcd->daddr);

                len -= size;
                if (cur_addr >= dma_addr && cur_addr < dma_addr + size) {
                        len += dma_addr + size - cur_addr;
                        break;
                }
        }

        return len;
}

static enum dma_status fsl_edma_tx_status(struct dma_chan *chan,
                dma_cookie_t cookie, struct dma_tx_state *txstate)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        struct virt_dma_desc *vdesc;
        enum dma_status status;
        unsigned long flags;

        status = dma_cookie_status(chan, cookie, txstate);
        if (status == DMA_COMPLETE)
                return status;

        if (!txstate)
                return fsl_chan->status;

        spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
        vdesc = vchan_find_desc(&fsl_chan->vchan, cookie);
        if (fsl_chan->edesc && cookie == fsl_chan->edesc->vdesc.tx.cookie)
                txstate->residue = fsl_edma_desc_residue(fsl_chan, vdesc, true);
        else if (vdesc)
                txstate->residue = fsl_edma_desc_residue(fsl_chan, vdesc, false);
        else
                txstate->residue = 0;

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

        return fsl_chan->status;
}

static void fsl_edma_set_tcd_regs(struct fsl_edma_chan *fsl_chan,
                                  struct fsl_edma_hw_tcd *tcd)
{
        struct fsl_edma_engine *edma = fsl_chan->edma;
        void __iomem *addr = fsl_chan->edma->membase;
        u32 ch = fsl_chan->vchan.chan.chan_id;

        /*
         * TCD parameters are stored in struct fsl_edma_hw_tcd in little
         * endian format. However, we need to load the TCD registers in
         * big- or little-endian obeying the eDMA engine model endian.
         */
        edma_writew(edma, 0, addr + EDMA_TCD_CSR(ch));
        edma_writel(edma, le32_to_cpu(tcd->saddr), addr + EDMA_TCD_SADDR(ch));
        edma_writel(edma, le32_to_cpu(tcd->daddr), addr + EDMA_TCD_DADDR(ch));

        edma_writew(edma, le16_to_cpu(tcd->attr), addr + EDMA_TCD_ATTR(ch));
        edma_writew(edma, le16_to_cpu(tcd->soff), addr + EDMA_TCD_SOFF(ch));

        edma_writel(edma, le32_to_cpu(tcd->nbytes), addr + EDMA_TCD_NBYTES(ch));
        edma_writel(edma, le32_to_cpu(tcd->slast), addr + EDMA_TCD_SLAST(ch));

        edma_writew(edma, le16_to_cpu(tcd->citer), addr + EDMA_TCD_CITER(ch));
        edma_writew(edma, le16_to_cpu(tcd->biter), addr + EDMA_TCD_BITER(ch));
        edma_writew(edma, le16_to_cpu(tcd->doff), addr + EDMA_TCD_DOFF(ch));

        edma_writel(edma, le32_to_cpu(tcd->dlast_sga), addr + EDMA_TCD_DLAST_SGA(ch));

        edma_writew(edma, le16_to_cpu(tcd->csr), addr + EDMA_TCD_CSR(ch));
}

static inline
void fsl_edma_fill_tcd(struct fsl_edma_hw_tcd *tcd, u32 src, u32 dst,
                       u16 attr, u16 soff, u32 nbytes, u32 slast, u16 citer,
                       u16 biter, u16 doff, u32 dlast_sga, bool major_int,
                       bool disable_req, bool enable_sg)
{
        u16 csr = 0;

        /*
         * eDMA hardware SGs require the TCDs to be stored in little
         * endian format irrespective of the register endian model.
         * So we put the value in little endian in memory, waiting
         * for fsl_edma_set_tcd_regs doing the swap.
         */
        tcd->saddr = cpu_to_le32(src);
        tcd->daddr = cpu_to_le32(dst);

        tcd->attr = cpu_to_le16(attr);

        tcd->soff = cpu_to_le16(EDMA_TCD_SOFF_SOFF(soff));

        tcd->nbytes = cpu_to_le32(EDMA_TCD_NBYTES_NBYTES(nbytes));
        tcd->slast = cpu_to_le32(EDMA_TCD_SLAST_SLAST(slast));

        tcd->citer = cpu_to_le16(EDMA_TCD_CITER_CITER(citer));
        tcd->doff = cpu_to_le16(EDMA_TCD_DOFF_DOFF(doff));

        tcd->dlast_sga = cpu_to_le32(EDMA_TCD_DLAST_SGA_DLAST_SGA(dlast_sga));

        tcd->biter = cpu_to_le16(EDMA_TCD_BITER_BITER(biter));
        if (major_int)
                csr |= EDMA_TCD_CSR_INT_MAJOR;

        if (disable_req)
                csr |= EDMA_TCD_CSR_D_REQ;

        if (enable_sg)
                csr |= EDMA_TCD_CSR_E_SG;

        tcd->csr = cpu_to_le16(csr);
}

static struct fsl_edma_desc *fsl_edma_alloc_desc(struct fsl_edma_chan *fsl_chan,
                int sg_len)
{
        struct fsl_edma_desc *fsl_desc;
        int i;

        fsl_desc = kzalloc(sizeof(*fsl_desc) + sizeof(struct fsl_edma_sw_tcd) * sg_len,
                                GFP_NOWAIT);
        if (!fsl_desc)
                return NULL;

        fsl_desc->echan = fsl_chan;
        fsl_desc->n_tcds = sg_len;
        for (i = 0; i < sg_len; i++) {
                fsl_desc->tcd[i].vtcd = dma_pool_alloc(fsl_chan->tcd_pool,
                                        GFP_NOWAIT, &fsl_desc->tcd[i].ptcd);
                if (!fsl_desc->tcd[i].vtcd)
                        goto err;
        }
        return fsl_desc;

err:
        while (--i >= 0)
                dma_pool_free(fsl_chan->tcd_pool, fsl_desc->tcd[i].vtcd,
                                fsl_desc->tcd[i].ptcd);
        kfree(fsl_desc);
        return NULL;
}

static struct dma_async_tx_descriptor *fsl_edma_prep_dma_cyclic(
                struct dma_chan *chan, dma_addr_t dma_addr, size_t buf_len,
                size_t period_len, enum dma_transfer_direction direction,
                unsigned long flags)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        struct fsl_edma_desc *fsl_desc;
        dma_addr_t dma_buf_next;
        int sg_len, i;
        u32 src_addr, dst_addr, last_sg, nbytes;
        u16 soff, doff, iter;

        if (!is_slave_direction(fsl_chan->fsc.dir))
                return NULL;

        sg_len = buf_len / period_len;
        fsl_desc = fsl_edma_alloc_desc(fsl_chan, sg_len);
        if (!fsl_desc)
                return NULL;
        fsl_desc->iscyclic = true;

        dma_buf_next = dma_addr;
        nbytes = fsl_chan->fsc.addr_width * fsl_chan->fsc.burst;
        iter = period_len / nbytes;

        for (i = 0; i < sg_len; i++) {
                if (dma_buf_next >= dma_addr + buf_len)
                        dma_buf_next = dma_addr;

                /* get next sg's physical address */
                last_sg = fsl_desc->tcd[(i + 1) % sg_len].ptcd;

                if (fsl_chan->fsc.dir == DMA_MEM_TO_DEV) {
                        src_addr = dma_buf_next;
                        dst_addr = fsl_chan->fsc.dev_addr;
                        soff = fsl_chan->fsc.addr_width;
                        doff = 0;
                } else {
                        src_addr = fsl_chan->fsc.dev_addr;
                        dst_addr = dma_buf_next;
                        soff = 0;
                        doff = fsl_chan->fsc.addr_width;
                }

                fsl_edma_fill_tcd(fsl_desc->tcd[i].vtcd, src_addr, dst_addr,
                                  fsl_chan->fsc.attr, soff, nbytes, 0, iter,
                                  iter, doff, last_sg, true, false, true);
                dma_buf_next += period_len;
        }

        return vchan_tx_prep(&fsl_chan->vchan, &fsl_desc->vdesc, flags);
}

static struct dma_async_tx_descriptor *fsl_edma_prep_slave_sg(
                struct dma_chan *chan, struct scatterlist *sgl,
                unsigned int sg_len, enum dma_transfer_direction direction,
                unsigned long flags, void *context)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        struct fsl_edma_desc *fsl_desc;
        struct scatterlist *sg;
        u32 src_addr, dst_addr, last_sg, nbytes;
        u16 soff, doff, iter;
        int i;

        if (!is_slave_direction(fsl_chan->fsc.dir))
                return NULL;

        fsl_desc = fsl_edma_alloc_desc(fsl_chan, sg_len);
        if (!fsl_desc)
                return NULL;
        fsl_desc->iscyclic = false;

        nbytes = fsl_chan->fsc.addr_width * fsl_chan->fsc.burst;
        for_each_sg(sgl, sg, sg_len, i) {
                /* get next sg's physical address */
                last_sg = fsl_desc->tcd[(i + 1) % sg_len].ptcd;

                if (fsl_chan->fsc.dir == DMA_MEM_TO_DEV) {
                        src_addr = sg_dma_address(sg);
                        dst_addr = fsl_chan->fsc.dev_addr;
                        soff = fsl_chan->fsc.addr_width;
                        doff = 0;
                } else {
                        src_addr = fsl_chan->fsc.dev_addr;
                        dst_addr = sg_dma_address(sg);
                        soff = 0;
                        doff = fsl_chan->fsc.addr_width;
                }

                iter = sg_dma_len(sg) / nbytes;
                if (i < sg_len - 1) {
                        last_sg = fsl_desc->tcd[(i + 1)].ptcd;
                        fsl_edma_fill_tcd(fsl_desc->tcd[i].vtcd, src_addr,
                                          dst_addr, fsl_chan->fsc.attr, soff,
                                          nbytes, 0, iter, iter, doff, last_sg,
                                          false, false, true);
                } else {
                        last_sg = 0;
                        fsl_edma_fill_tcd(fsl_desc->tcd[i].vtcd, src_addr,
                                          dst_addr, fsl_chan->fsc.attr, soff,
                                          nbytes, 0, iter, iter, doff, last_sg,
                                          true, true, false);
                }
        }

        return vchan_tx_prep(&fsl_chan->vchan, &fsl_desc->vdesc, flags);
}

static void fsl_edma_xfer_desc(struct fsl_edma_chan *fsl_chan)
{
        struct virt_dma_desc *vdesc;

        vdesc = vchan_next_desc(&fsl_chan->vchan);
        if (!vdesc)
                return;
        fsl_chan->edesc = to_fsl_edma_desc(vdesc);
        fsl_edma_set_tcd_regs(fsl_chan, fsl_chan->edesc->tcd[0].vtcd);
        fsl_edma_enable_request(fsl_chan);
        fsl_chan->status = DMA_IN_PROGRESS;
        fsl_chan->idle = false;
}

static irqreturn_t fsl_edma_tx_handler(int irq, void *dev_id)
{
        struct fsl_edma_engine *fsl_edma = dev_id;
        unsigned int intr, ch;
        void __iomem *base_addr;
        struct fsl_edma_chan *fsl_chan;

        base_addr = fsl_edma->membase;

        intr = edma_readl(fsl_edma, base_addr + EDMA_INTR);
        if (!intr)
                return IRQ_NONE;

        for (ch = 0; ch < fsl_edma->n_chans; ch++) {
                if (intr & (0x1 << ch)) {
                        edma_writeb(fsl_edma, EDMA_CINT_CINT(ch),
                                base_addr + EDMA_CINT);

                        fsl_chan = &fsl_edma->chans[ch];

                        spin_lock(&fsl_chan->vchan.lock);
                        if (!fsl_chan->edesc->iscyclic) {
                                list_del(&fsl_chan->edesc->vdesc.node);
                                vchan_cookie_complete(&fsl_chan->edesc->vdesc);
                                fsl_chan->edesc = NULL;
                                fsl_chan->status = DMA_COMPLETE;
                                fsl_chan->idle = true;
                        } else {
                                vchan_cyclic_callback(&fsl_chan->edesc->vdesc);
                        }

                        if (!fsl_chan->edesc)
                                fsl_edma_xfer_desc(fsl_chan);

                        spin_unlock(&fsl_chan->vchan.lock);
                }
        }
        return IRQ_HANDLED;
}

static irqreturn_t fsl_edma_err_handler(int irq, void *dev_id)
{
        struct fsl_edma_engine *fsl_edma = dev_id;
        unsigned int err, ch;

        err = edma_readl(fsl_edma, fsl_edma->membase + EDMA_ERR);
        if (!err)
                return IRQ_NONE;

        for (ch = 0; ch < fsl_edma->n_chans; ch++) {
                if (err & (0x1 << ch)) {
                        fsl_edma_disable_request(&fsl_edma->chans[ch]);
                        edma_writeb(fsl_edma, EDMA_CERR_CERR(ch),
                                fsl_edma->membase + EDMA_CERR);
                        fsl_edma->chans[ch].status = DMA_ERROR;
                        fsl_edma->chans[ch].idle = true;
                }
        }
        return IRQ_HANDLED;
}

static irqreturn_t fsl_edma_irq_handler(int irq, void *dev_id)
{
        if (fsl_edma_tx_handler(irq, dev_id) == IRQ_HANDLED)
                return IRQ_HANDLED;

        return fsl_edma_err_handler(irq, dev_id);
}

static void fsl_edma_issue_pending(struct dma_chan *chan)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        unsigned long flags;

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

        if (unlikely(fsl_chan->pm_state != RUNNING)) {
                spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
                /* cannot submit due to suspend */
                return;
        }

        if (vchan_issue_pending(&fsl_chan->vchan) && !fsl_chan->edesc)
                fsl_edma_xfer_desc(fsl_chan);

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

static struct dma_chan *fsl_edma_xlate(struct of_phandle_args *dma_spec,
                struct of_dma *ofdma)
{
        struct fsl_edma_engine *fsl_edma = ofdma->of_dma_data;
        struct dma_chan *chan, *_chan;
        struct fsl_edma_chan *fsl_chan;
        unsigned long chans_per_mux = fsl_edma->n_chans / DMAMUX_NR;

        if (dma_spec->args_count != 2)
                return NULL;

        mutex_lock(&fsl_edma->fsl_edma_mutex);
        list_for_each_entry_safe(chan, _chan, &fsl_edma->dma_dev.channels, device_node) {
                if (chan->client_count)
                        continue;
                if ((chan->chan_id / chans_per_mux) == dma_spec->args[0]) {
                        chan = dma_get_slave_channel(chan);
                        if (chan) {
                                chan->device->privatecnt++;
                                fsl_chan = to_fsl_edma_chan(chan);
                                fsl_chan->slave_id = dma_spec->args[1];
                                fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id,
                                                true);
                                mutex_unlock(&fsl_edma->fsl_edma_mutex);
                                return chan;
                        }
                }
        }
        mutex_unlock(&fsl_edma->fsl_edma_mutex);
        return NULL;
}

static int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);

        fsl_chan->tcd_pool = dma_pool_create("tcd_pool", chan->device->dev,
                                sizeof(struct fsl_edma_hw_tcd),
                                32, 0);
        return 0;
}

static void fsl_edma_free_chan_resources(struct dma_chan *chan)
{
        struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
        unsigned long flags;
        LIST_HEAD(head);

        spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
        fsl_edma_disable_request(fsl_chan);
        fsl_edma_chan_mux(fsl_chan, 0, false);
        fsl_chan->edesc = NULL;
        vchan_get_all_descriptors(&fsl_chan->vchan, &head);
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);

        vchan_dma_desc_free_list(&fsl_chan->vchan, &head);
        dma_pool_destroy(fsl_chan->tcd_pool);
        fsl_chan->tcd_pool = NULL;
}

static int
fsl_edma_irq_init(struct platform_device *pdev, struct fsl_edma_engine *fsl_edma)
{
        int ret;

        fsl_edma->txirq = platform_get_irq_byname(pdev, "edma-tx");
        if (fsl_edma->txirq < 0) {
                dev_err(&pdev->dev, "Can't get edma-tx irq.\n");
                return fsl_edma->txirq;
        }

        fsl_edma->errirq = platform_get_irq_byname(pdev, "edma-err");
        if (fsl_edma->errirq < 0) {
                dev_err(&pdev->dev, "Can't get edma-err irq.\n");
                return fsl_edma->errirq;
        }

        if (fsl_edma->txirq == fsl_edma->errirq) {
                ret = devm_request_irq(&pdev->dev, fsl_edma->txirq,
                                fsl_edma_irq_handler, 0, "eDMA", fsl_edma);
                if (ret) {
                        dev_err(&pdev->dev, "Can't register eDMA IRQ.\n");
                         return  ret;
                }
        } else {
                ret = devm_request_irq(&pdev->dev, fsl_edma->txirq,
                                fsl_edma_tx_handler, 0, "eDMA tx", fsl_edma);
                if (ret) {
                        dev_err(&pdev->dev, "Can't register eDMA tx IRQ.\n");
                        return  ret;
                }

                ret = devm_request_irq(&pdev->dev, fsl_edma->errirq,
                                fsl_edma_err_handler, 0, "eDMA err", fsl_edma);
                if (ret) {
                        dev_err(&pdev->dev, "Can't register eDMA err IRQ.\n");
                        return  ret;
                }
        }

        return 0;
}

static void fsl_edma_irq_exit(
                struct platform_device *pdev, struct fsl_edma_engine *fsl_edma)
{
        if (fsl_edma->txirq == fsl_edma->errirq) {
                devm_free_irq(&pdev->dev, fsl_edma->txirq, fsl_edma);
        } else {
                devm_free_irq(&pdev->dev, fsl_edma->txirq, fsl_edma);
                devm_free_irq(&pdev->dev, fsl_edma->errirq, fsl_edma);
        }
}

static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma)
{
        int i;

        for (i = 0; i < DMAMUX_NR; i++)
                clk_disable_unprepare(fsl_edma->muxclk[i]);
}

static int fsl_edma_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct fsl_edma_engine *fsl_edma;
        struct fsl_edma_chan *fsl_chan;
        struct resource *res;
        int len, chans;
        int ret, i;

        ret = of_property_read_u32(np, "dma-channels", &chans);
        if (ret) {
                dev_err(&pdev->dev, "Can't get dma-channels.\n");
                return ret;
        }

        len = sizeof(*fsl_edma) + sizeof(*fsl_chan) * chans;
        fsl_edma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
        if (!fsl_edma)
                return -ENOMEM;

        fsl_edma->n_chans = chans;
        mutex_init(&fsl_edma->fsl_edma_mutex);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        fsl_edma->membase = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(fsl_edma->membase))
                return PTR_ERR(fsl_edma->membase);

        for (i = 0; i < DMAMUX_NR; i++) {
                char clkname[32];

                res = platform_get_resource(pdev, IORESOURCE_MEM, 1 + i);
                fsl_edma->muxbase[i] = devm_ioremap_resource(&pdev->dev, res);
                if (IS_ERR(fsl_edma->muxbase[i]))
                        return PTR_ERR(fsl_edma->muxbase[i]);

                sprintf(clkname, "dmamux%d", i);
                fsl_edma->muxclk[i] = devm_clk_get(&pdev->dev, clkname);
                if (IS_ERR(fsl_edma->muxclk[i])) {
                        dev_err(&pdev->dev, "Missing DMAMUX block clock.\n");
                        return PTR_ERR(fsl_edma->muxclk[i]);
                }

                ret = clk_prepare_enable(fsl_edma->muxclk[i]);
                if (ret) {
                        /* disable only clks which were enabled on error */
                        for (; i >= 0; i--)
                                clk_disable_unprepare(fsl_edma->muxclk[i]);

                        dev_err(&pdev->dev, "DMAMUX clk block failed.\n");
                        return ret;
                }

        }

        fsl_edma->big_endian = of_property_read_bool(np, "big-endian");

        INIT_LIST_HEAD(&fsl_edma->dma_dev.channels);
        for (i = 0; i < fsl_edma->n_chans; i++) {
                struct fsl_edma_chan *fsl_chan = &fsl_edma->chans[i];

                fsl_chan->edma = fsl_edma;
                fsl_chan->pm_state = RUNNING;
                fsl_chan->slave_id = 0;
                fsl_chan->idle = true;
                fsl_chan->vchan.desc_free = fsl_edma_free_desc;
                vchan_init(&fsl_chan->vchan, &fsl_edma->dma_dev);

                edma_writew(fsl_edma, 0x0, fsl_edma->membase + EDMA_TCD_CSR(i));
                fsl_edma_chan_mux(fsl_chan, 0, false);
        }

        edma_writel(fsl_edma, ~0, fsl_edma->membase + EDMA_INTR);
        ret = fsl_edma_irq_init(pdev, fsl_edma);
        if (ret)
                return ret;

        dma_cap_set(DMA_PRIVATE, fsl_edma->dma_dev.cap_mask);
        dma_cap_set(DMA_SLAVE, fsl_edma->dma_dev.cap_mask);
        dma_cap_set(DMA_CYCLIC, fsl_edma->dma_dev.cap_mask);

        fsl_edma->dma_dev.dev = &pdev->dev;
        fsl_edma->dma_dev.device_alloc_chan_resources
                = fsl_edma_alloc_chan_resources;
        fsl_edma->dma_dev.device_free_chan_resources
                = fsl_edma_free_chan_resources;
        fsl_edma->dma_dev.device_tx_status = fsl_edma_tx_status;
        fsl_edma->dma_dev.device_prep_slave_sg = fsl_edma_prep_slave_sg;
        fsl_edma->dma_dev.device_prep_dma_cyclic = fsl_edma_prep_dma_cyclic;
        fsl_edma->dma_dev.device_config = fsl_edma_slave_config;
        fsl_edma->dma_dev.device_pause = fsl_edma_pause;
        fsl_edma->dma_dev.device_resume = fsl_edma_resume;
        fsl_edma->dma_dev.device_terminate_all = fsl_edma_terminate_all;
        fsl_edma->dma_dev.device_issue_pending = fsl_edma_issue_pending;

        fsl_edma->dma_dev.src_addr_widths = FSL_EDMA_BUSWIDTHS;
        fsl_edma->dma_dev.dst_addr_widths = FSL_EDMA_BUSWIDTHS;
        fsl_edma->dma_dev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);

        platform_set_drvdata(pdev, fsl_edma);

        ret = dma_async_device_register(&fsl_edma->dma_dev);
        if (ret) {
                dev_err(&pdev->dev,
                        "Can't register Freescale eDMA engine. (%d)\n", ret);
                fsl_disable_clocks(fsl_edma);
                return ret;
        }

        ret = of_dma_controller_register(np, fsl_edma_xlate, fsl_edma);
        if (ret) {
                dev_err(&pdev->dev,
                        "Can't register Freescale eDMA of_dma. (%d)\n", ret);
                dma_async_device_unregister(&fsl_edma->dma_dev);
                fsl_disable_clocks(fsl_edma);
                return ret;
        }

        /* enable round robin arbitration */
        edma_writel(fsl_edma, EDMA_CR_ERGA | EDMA_CR_ERCA, fsl_edma->membase + EDMA_CR);

        return 0;
}

static void fsl_edma_cleanup_vchan(struct dma_device *dmadev)
{
        struct fsl_edma_chan *chan, *_chan;

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

static int fsl_edma_remove(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct fsl_edma_engine *fsl_edma = platform_get_drvdata(pdev);

        fsl_edma_irq_exit(pdev, fsl_edma);
        fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
        of_dma_controller_free(np);
        dma_async_device_unregister(&fsl_edma->dma_dev);
        fsl_disable_clocks(fsl_edma);

        return 0;
}

static int fsl_edma_suspend_late(struct device *dev)
{
        struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
        struct fsl_edma_chan *fsl_chan;
        unsigned long flags;
        int i;

        for (i = 0; i < fsl_edma->n_chans; i++) {
                fsl_chan = &fsl_edma->chans[i];
                spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
                /* Make sure chan is idle or will force disable. */
                if (unlikely(!fsl_chan->idle)) {
                        dev_warn(dev, "WARN: There is non-idle channel.");
                        fsl_edma_disable_request(fsl_chan);
                        fsl_edma_chan_mux(fsl_chan, 0, false);
                }

                fsl_chan->pm_state = SUSPENDED;
                spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        }

        return 0;
}

static int fsl_edma_resume_early(struct device *dev)
{
        struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
        struct fsl_edma_chan *fsl_chan;
        int i;

        for (i = 0; i < fsl_edma->n_chans; i++) {
                fsl_chan = &fsl_edma->chans[i];
                fsl_chan->pm_state = RUNNING;
                edma_writew(fsl_edma, 0x0, fsl_edma->membase + EDMA_TCD_CSR(i));
                if (fsl_chan->slave_id != 0)
                        fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id, true);
        }

        edma_writel(fsl_edma, EDMA_CR_ERGA | EDMA_CR_ERCA,
                        fsl_edma->membase + EDMA_CR);

        return 0;
}

/*
 * eDMA provides the service to others, so it should be suspend late
 * and resume early. When eDMA suspend, all of the clients should stop
 * the DMA data transmission and let the channel idle.
 */
static const struct dev_pm_ops fsl_edma_pm_ops = {
        .suspend_late   = fsl_edma_suspend_late,
        .resume_early   = fsl_edma_resume_early,
};

static const struct of_device_id fsl_edma_dt_ids[] = {
        { .compatible = "fsl,vf610-edma", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, fsl_edma_dt_ids);

static struct platform_driver fsl_edma_driver = {
        .driver         = {
                .name   = "fsl-edma",
                .of_match_table = fsl_edma_dt_ids,
                .pm     = &fsl_edma_pm_ops,
        },
        .probe          = fsl_edma_probe,
        .remove         = fsl_edma_remove,
};

static int __init fsl_edma_init(void)
{
        return platform_driver_register(&fsl_edma_driver);
}
subsys_initcall(fsl_edma_init);

static void __exit fsl_edma_exit(void)
{
        platform_driver_unregister(&fsl_edma_driver);
}
module_exit(fsl_edma_exit);

MODULE_ALIAS("platform:fsl-edma");
MODULE_DESCRIPTION("Freescale eDMA engine driver");
MODULE_LICENSE("GPL v2");