// SPDX-License-Identifier:  GPL-2.0
// (C) 2017-2018 Synopsys, Inc. (www.synopsys.com)

/*
 * Synopsys DesignWare AXI DMA Controller driver.
 *
 * Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/types.h>

#include "dw-axi-dmac.h"
#include "../dmaengine.h"
#include "../virt-dma.h"

/*
 * The set of bus widths supported by the DMA controller. DW AXI DMAC supports
 * master data bus width up to 512 bits (for both AXI master interfaces), but
 * it depends on IP block configurarion.
 */
#define AXI_DMA_BUSWIDTHS                 \
        (DMA_SLAVE_BUSWIDTH_1_BYTE      | \
        DMA_SLAVE_BUSWIDTH_2_BYTES      | \
        DMA_SLAVE_BUSWIDTH_4_BYTES      | \
        DMA_SLAVE_BUSWIDTH_8_BYTES      | \
        DMA_SLAVE_BUSWIDTH_16_BYTES     | \
        DMA_SLAVE_BUSWIDTH_32_BYTES     | \
        DMA_SLAVE_BUSWIDTH_64_BYTES)

static inline void
axi_dma_iowrite32(struct axi_dma_chip *chip, u32 reg, u32 val)
{
        iowrite32(val, chip->regs + reg);
}

static inline u32 axi_dma_ioread32(struct axi_dma_chip *chip, u32 reg)
{
        return ioread32(chip->regs + reg);
}

static inline void
axi_chan_iowrite32(struct axi_dma_chan *chan, u32 reg, u32 val)
{
        iowrite32(val, chan->chan_regs + reg);
}

static inline u32 axi_chan_ioread32(struct axi_dma_chan *chan, u32 reg)
{
        return ioread32(chan->chan_regs + reg);
}

static inline void
axi_chan_iowrite64(struct axi_dma_chan *chan, u32 reg, u64 val)
{
        /*
         * We split one 64 bit write for two 32 bit write as some HW doesn't
         * support 64 bit access.
         */
        iowrite32(lower_32_bits(val), chan->chan_regs + reg);
        iowrite32(upper_32_bits(val), chan->chan_regs + reg + 4);
}

static inline void axi_dma_disable(struct axi_dma_chip *chip)
{
        u32 val;

        val = axi_dma_ioread32(chip, DMAC_CFG);
        val &= ~DMAC_EN_MASK;
        axi_dma_iowrite32(chip, DMAC_CFG, val);
}

static inline void axi_dma_enable(struct axi_dma_chip *chip)
{
        u32 val;

        val = axi_dma_ioread32(chip, DMAC_CFG);
        val |= DMAC_EN_MASK;
        axi_dma_iowrite32(chip, DMAC_CFG, val);
}

static inline void axi_dma_irq_disable(struct axi_dma_chip *chip)
{
        u32 val;

        val = axi_dma_ioread32(chip, DMAC_CFG);
        val &= ~INT_EN_MASK;
        axi_dma_iowrite32(chip, DMAC_CFG, val);
}

static inline void axi_dma_irq_enable(struct axi_dma_chip *chip)
{
        u32 val;

        val = axi_dma_ioread32(chip, DMAC_CFG);
        val |= INT_EN_MASK;
        axi_dma_iowrite32(chip, DMAC_CFG, val);
}

static inline void axi_chan_irq_disable(struct axi_dma_chan *chan, u32 irq_mask)
{
        u32 val;

        if (likely(irq_mask == DWAXIDMAC_IRQ_ALL)) {
                axi_chan_iowrite32(chan, CH_INTSTATUS_ENA, DWAXIDMAC_IRQ_NONE);
        } else {
                val = axi_chan_ioread32(chan, CH_INTSTATUS_ENA);
                val &= ~irq_mask;
                axi_chan_iowrite32(chan, CH_INTSTATUS_ENA, val);
        }
}

static inline void axi_chan_irq_set(struct axi_dma_chan *chan, u32 irq_mask)
{
        axi_chan_iowrite32(chan, CH_INTSTATUS_ENA, irq_mask);
}

static inline void axi_chan_irq_sig_set(struct axi_dma_chan *chan, u32 irq_mask)
{
        axi_chan_iowrite32(chan, CH_INTSIGNAL_ENA, irq_mask);
}

static inline void axi_chan_irq_clear(struct axi_dma_chan *chan, u32 irq_mask)
{
        axi_chan_iowrite32(chan, CH_INTCLEAR, irq_mask);
}

static inline u32 axi_chan_irq_read(struct axi_dma_chan *chan)
{
        return axi_chan_ioread32(chan, CH_INTSTATUS);
}

static inline void axi_chan_disable(struct axi_dma_chan *chan)
{
        u32 val;

        val = axi_dma_ioread32(chan->chip, DMAC_CHEN);
        val &= ~(BIT(chan->id) << DMAC_CHAN_EN_SHIFT);
        val |=   BIT(chan->id) << DMAC_CHAN_EN_WE_SHIFT;
        axi_dma_iowrite32(chan->chip, DMAC_CHEN, val);
}

static inline void axi_chan_enable(struct axi_dma_chan *chan)
{
        u32 val;

        val = axi_dma_ioread32(chan->chip, DMAC_CHEN);
        val |= BIT(chan->id) << DMAC_CHAN_EN_SHIFT |
               BIT(chan->id) << DMAC_CHAN_EN_WE_SHIFT;
        axi_dma_iowrite32(chan->chip, DMAC_CHEN, val);
}

static inline bool axi_chan_is_hw_enable(struct axi_dma_chan *chan)
{
        u32 val;

        val = axi_dma_ioread32(chan->chip, DMAC_CHEN);

        return !!(val & (BIT(chan->id) << DMAC_CHAN_EN_SHIFT));
}

static void axi_dma_hw_init(struct axi_dma_chip *chip)
{
        u32 i;

        for (i = 0; i < chip->dw->hdata->nr_channels; i++) {
                axi_chan_irq_disable(&chip->dw->chan[i], DWAXIDMAC_IRQ_ALL);
                axi_chan_disable(&chip->dw->chan[i]);
        }
}

static u32 axi_chan_get_xfer_width(struct axi_dma_chan *chan, dma_addr_t src,
                                   dma_addr_t dst, size_t len)
{
        u32 max_width = chan->chip->dw->hdata->m_data_width;

        return __ffs(src | dst | len | BIT(max_width));
}

static inline const char *axi_chan_name(struct axi_dma_chan *chan)
{
        return dma_chan_name(&chan->vc.chan);
}

static struct axi_dma_desc *axi_desc_get(struct axi_dma_chan *chan)
{
        struct dw_axi_dma *dw = chan->chip->dw;
        struct axi_dma_desc *desc;
        dma_addr_t phys;

        desc = dma_pool_zalloc(dw->desc_pool, GFP_NOWAIT, &phys);
        if (unlikely(!desc)) {
                dev_err(chan2dev(chan), "%s: not enough descriptors available\n",
                        axi_chan_name(chan));
                return NULL;
        }

        atomic_inc(&chan->descs_allocated);
        INIT_LIST_HEAD(&desc->xfer_list);
        desc->vd.tx.phys = phys;
        desc->chan = chan;

        return desc;
}

static void axi_desc_put(struct axi_dma_desc *desc)
{
        struct axi_dma_chan *chan = desc->chan;
        struct dw_axi_dma *dw = chan->chip->dw;
        struct axi_dma_desc *child, *_next;
        unsigned int descs_put = 0;

        list_for_each_entry_safe(child, _next, &desc->xfer_list, xfer_list) {
                list_del(&child->xfer_list);
                dma_pool_free(dw->desc_pool, child, child->vd.tx.phys);
                descs_put++;
        }

        dma_pool_free(dw->desc_pool, desc, desc->vd.tx.phys);
        descs_put++;

        atomic_sub(descs_put, &chan->descs_allocated);
        dev_vdbg(chan2dev(chan), "%s: %d descs put, %d still allocated\n",
                axi_chan_name(chan), descs_put,
                atomic_read(&chan->descs_allocated));
}

static void vchan_desc_put(struct virt_dma_desc *vdesc)
{
        axi_desc_put(vd_to_axi_desc(vdesc));
}

static enum dma_status
dma_chan_tx_status(struct dma_chan *dchan, dma_cookie_t cookie,
                  struct dma_tx_state *txstate)
{
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
        enum dma_status ret;

        ret = dma_cookie_status(dchan, cookie, txstate);

        if (chan->is_paused && ret == DMA_IN_PROGRESS)
                ret = DMA_PAUSED;

        return ret;
}

static void write_desc_llp(struct axi_dma_desc *desc, dma_addr_t adr)
{
        desc->lli.llp = cpu_to_le64(adr);
}

static void write_chan_llp(struct axi_dma_chan *chan, dma_addr_t adr)
{
        axi_chan_iowrite64(chan, CH_LLP, adr);
}

/* Called in chan locked context */
static void axi_chan_block_xfer_start(struct axi_dma_chan *chan,
                                      struct axi_dma_desc *first)
{
        u32 priority = chan->chip->dw->hdata->priority[chan->id];
        u32 reg, irq_mask;
        u8 lms = 0; /* Select AXI0 master for LLI fetching */

        if (unlikely(axi_chan_is_hw_enable(chan))) {
                dev_err(chan2dev(chan), "%s is non-idle!\n",
                        axi_chan_name(chan));

                return;
        }

        axi_dma_enable(chan->chip);

        reg = (DWAXIDMAC_MBLK_TYPE_LL << CH_CFG_L_DST_MULTBLK_TYPE_POS |
               DWAXIDMAC_MBLK_TYPE_LL << CH_CFG_L_SRC_MULTBLK_TYPE_POS);
        axi_chan_iowrite32(chan, CH_CFG_L, reg);

        reg = (DWAXIDMAC_TT_FC_MEM_TO_MEM_DMAC << CH_CFG_H_TT_FC_POS |
               priority << CH_CFG_H_PRIORITY_POS |
               DWAXIDMAC_HS_SEL_HW << CH_CFG_H_HS_SEL_DST_POS |
               DWAXIDMAC_HS_SEL_HW << CH_CFG_H_HS_SEL_SRC_POS);
        axi_chan_iowrite32(chan, CH_CFG_H, reg);

        write_chan_llp(chan, first->vd.tx.phys | lms);

        irq_mask = DWAXIDMAC_IRQ_DMA_TRF | DWAXIDMAC_IRQ_ALL_ERR;
        axi_chan_irq_sig_set(chan, irq_mask);

        /* Generate 'suspend' status but don't generate interrupt */
        irq_mask |= DWAXIDMAC_IRQ_SUSPENDED;
        axi_chan_irq_set(chan, irq_mask);

        axi_chan_enable(chan);
}

static void axi_chan_start_first_queued(struct axi_dma_chan *chan)
{
        struct axi_dma_desc *desc;
        struct virt_dma_desc *vd;

        vd = vchan_next_desc(&chan->vc);
        if (!vd)
                return;

        desc = vd_to_axi_desc(vd);
        dev_vdbg(chan2dev(chan), "%s: started %u\n", axi_chan_name(chan),
                vd->tx.cookie);
        axi_chan_block_xfer_start(chan, desc);
}

static void dma_chan_issue_pending(struct dma_chan *dchan)
{
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
        unsigned long flags;

        spin_lock_irqsave(&chan->vc.lock, flags);
        if (vchan_issue_pending(&chan->vc))
                axi_chan_start_first_queued(chan);
        spin_unlock_irqrestore(&chan->vc.lock, flags);
}

static int dma_chan_alloc_chan_resources(struct dma_chan *dchan)
{
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);

        /* ASSERT: channel is idle */
        if (axi_chan_is_hw_enable(chan)) {
                dev_err(chan2dev(chan), "%s is non-idle!\n",
                        axi_chan_name(chan));
                return -EBUSY;
        }

        dev_vdbg(dchan2dev(dchan), "%s: allocating\n", axi_chan_name(chan));

        pm_runtime_get(chan->chip->dev);

        return 0;
}

static void dma_chan_free_chan_resources(struct dma_chan *dchan)
{
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);

        /* ASSERT: channel is idle */
        if (axi_chan_is_hw_enable(chan))
                dev_err(dchan2dev(dchan), "%s is non-idle!\n",
                        axi_chan_name(chan));

        axi_chan_disable(chan);
        axi_chan_irq_disable(chan, DWAXIDMAC_IRQ_ALL);

        vchan_free_chan_resources(&chan->vc);

        dev_vdbg(dchan2dev(dchan),
                 "%s: free resources, descriptor still allocated: %u\n",
                 axi_chan_name(chan), atomic_read(&chan->descs_allocated));

        pm_runtime_put(chan->chip->dev);
}

/*
 * If DW_axi_dmac sees CHx_CTL.ShadowReg_Or_LLI_Last bit of the fetched LLI
 * as 1, it understands that the current block is the final block in the
 * transfer and completes the DMA transfer operation at the end of current
 * block transfer.
 */
static void set_desc_last(struct axi_dma_desc *desc)
{
        u32 val;

        val = le32_to_cpu(desc->lli.ctl_hi);
        val |= CH_CTL_H_LLI_LAST;
        desc->lli.ctl_hi = cpu_to_le32(val);
}

static void write_desc_sar(struct axi_dma_desc *desc, dma_addr_t adr)
{
        desc->lli.sar = cpu_to_le64(adr);
}

static void write_desc_dar(struct axi_dma_desc *desc, dma_addr_t adr)
{
        desc->lli.dar = cpu_to_le64(adr);
}

static void set_desc_src_master(struct axi_dma_desc *desc)
{
        u32 val;

        /* Select AXI0 for source master */
        val = le32_to_cpu(desc->lli.ctl_lo);
        val &= ~CH_CTL_L_SRC_MAST;
        desc->lli.ctl_lo = cpu_to_le32(val);
}

static void set_desc_dest_master(struct axi_dma_desc *desc)
{
        u32 val;

        /* Select AXI1 for source master if available */
        val = le32_to_cpu(desc->lli.ctl_lo);
        if (desc->chan->chip->dw->hdata->nr_masters > 1)
                val |= CH_CTL_L_DST_MAST;
        else
                val &= ~CH_CTL_L_DST_MAST;

        desc->lli.ctl_lo = cpu_to_le32(val);
}

static struct dma_async_tx_descriptor *
dma_chan_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dst_adr,
                         dma_addr_t src_adr, size_t len, unsigned long flags)
{
        struct axi_dma_desc *first = NULL, *desc = NULL, *prev = NULL;
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
        size_t block_ts, max_block_ts, xfer_len;
        u32 xfer_width, reg;
        u8 lms = 0; /* Select AXI0 master for LLI fetching */

        dev_dbg(chan2dev(chan), "%s: memcpy: src: %pad dst: %pad length: %zd flags: %#lx",
                axi_chan_name(chan), &src_adr, &dst_adr, len, flags);

        max_block_ts = chan->chip->dw->hdata->block_size[chan->id];

        while (len) {
                xfer_len = len;

                /*
                 * Take care for the alignment.
                 * Actually source and destination widths can be different, but
                 * make them same to be simpler.
                 */
                xfer_width = axi_chan_get_xfer_width(chan, src_adr, dst_adr, xfer_len);

                /*
                 * block_ts indicates the total number of data of width
                 * to be transferred in a DMA block transfer.
                 * BLOCK_TS register should be set to block_ts - 1
                 */
                block_ts = xfer_len >> xfer_width;
                if (block_ts > max_block_ts) {
                        block_ts = max_block_ts;
                        xfer_len = max_block_ts << xfer_width;
                }

                desc = axi_desc_get(chan);
                if (unlikely(!desc))
                        goto err_desc_get;

                write_desc_sar(desc, src_adr);
                write_desc_dar(desc, dst_adr);
                desc->lli.block_ts_lo = cpu_to_le32(block_ts - 1);

                reg = CH_CTL_H_LLI_VALID;
                if (chan->chip->dw->hdata->restrict_axi_burst_len) {
                        u32 burst_len = chan->chip->dw->hdata->axi_rw_burst_len;

                        reg |= (CH_CTL_H_ARLEN_EN |
                                burst_len << CH_CTL_H_ARLEN_POS |
                                CH_CTL_H_AWLEN_EN |
                                burst_len << CH_CTL_H_AWLEN_POS);
                }
                desc->lli.ctl_hi = cpu_to_le32(reg);

                reg = (DWAXIDMAC_BURST_TRANS_LEN_4 << CH_CTL_L_DST_MSIZE_POS |
                       DWAXIDMAC_BURST_TRANS_LEN_4 << CH_CTL_L_SRC_MSIZE_POS |
                       xfer_width << CH_CTL_L_DST_WIDTH_POS |
                       xfer_width << CH_CTL_L_SRC_WIDTH_POS |
                       DWAXIDMAC_CH_CTL_L_INC << CH_CTL_L_DST_INC_POS |
                       DWAXIDMAC_CH_CTL_L_INC << CH_CTL_L_SRC_INC_POS);
                desc->lli.ctl_lo = cpu_to_le32(reg);

                set_desc_src_master(desc);
                set_desc_dest_master(desc);

                /* Manage transfer list (xfer_list) */
                if (!first) {
                        first = desc;
                } else {
                        list_add_tail(&desc->xfer_list, &first->xfer_list);
                        write_desc_llp(prev, desc->vd.tx.phys | lms);
                }
                prev = desc;

                /* update the length and addresses for the next loop cycle */
                len -= xfer_len;
                dst_adr += xfer_len;
                src_adr += xfer_len;
        }

        /* Total len of src/dest sg == 0, so no descriptor were allocated */
        if (unlikely(!first))
                return NULL;

        /* Set end-of-link to the last link descriptor of list */
        set_desc_last(desc);

        return vchan_tx_prep(&chan->vc, &first->vd, flags);

err_desc_get:
        axi_desc_put(first);
        return NULL;
}

static void axi_chan_dump_lli(struct axi_dma_chan *chan,
                              struct axi_dma_desc *desc)
{
        dev_err(dchan2dev(&chan->vc.chan),
                "SAR: 0x%llx DAR: 0x%llx LLP: 0x%llx BTS 0x%x CTL: 0x%x:%08x",
                le64_to_cpu(desc->lli.sar),
                le64_to_cpu(desc->lli.dar),
                le64_to_cpu(desc->lli.llp),
                le32_to_cpu(desc->lli.block_ts_lo),
                le32_to_cpu(desc->lli.ctl_hi),
                le32_to_cpu(desc->lli.ctl_lo));
}

static void axi_chan_list_dump_lli(struct axi_dma_chan *chan,
                                   struct axi_dma_desc *desc_head)
{
        struct axi_dma_desc *desc;

        axi_chan_dump_lli(chan, desc_head);
        list_for_each_entry(desc, &desc_head->xfer_list, xfer_list)
                axi_chan_dump_lli(chan, desc);
}

static noinline void axi_chan_handle_err(struct axi_dma_chan *chan, u32 status)
{
        struct virt_dma_desc *vd;
        unsigned long flags;

        spin_lock_irqsave(&chan->vc.lock, flags);

        axi_chan_disable(chan);

        /* The bad descriptor currently is in the head of vc list */
        vd = vchan_next_desc(&chan->vc);
        /* Remove the completed descriptor from issued list */
        list_del(&vd->node);

        /* WARN about bad descriptor */
        dev_err(chan2dev(chan),
                "Bad descriptor submitted for %s, cookie: %d, irq: 0x%08x\n",
                axi_chan_name(chan), vd->tx.cookie, status);
        axi_chan_list_dump_lli(chan, vd_to_axi_desc(vd));

        vchan_cookie_complete(vd);

        /* Try to restart the controller */
        axi_chan_start_first_queued(chan);

        spin_unlock_irqrestore(&chan->vc.lock, flags);
}

static void axi_chan_block_xfer_complete(struct axi_dma_chan *chan)
{
        struct virt_dma_desc *vd;
        unsigned long flags;

        spin_lock_irqsave(&chan->vc.lock, flags);
        if (unlikely(axi_chan_is_hw_enable(chan))) {
                dev_err(chan2dev(chan), "BUG: %s caught DWAXIDMAC_IRQ_DMA_TRF, but channel not idle!\n",
                        axi_chan_name(chan));
                axi_chan_disable(chan);
        }

        /* The completed descriptor currently is in the head of vc list */
        vd = vchan_next_desc(&chan->vc);
        /* Remove the completed descriptor from issued list before completing */
        list_del(&vd->node);
        vchan_cookie_complete(vd);

        /* Submit queued descriptors after processing the completed ones */
        axi_chan_start_first_queued(chan);

        spin_unlock_irqrestore(&chan->vc.lock, flags);
}

static irqreturn_t dw_axi_dma_interrupt(int irq, void *dev_id)
{
        struct axi_dma_chip *chip = dev_id;
        struct dw_axi_dma *dw = chip->dw;
        struct axi_dma_chan *chan;

        u32 status, i;

        /* Disable DMAC inerrupts. We'll enable them after processing chanels */
        axi_dma_irq_disable(chip);

        /* Poll, clear and process every chanel interrupt status */
        for (i = 0; i < dw->hdata->nr_channels; i++) {
                chan = &dw->chan[i];
                status = axi_chan_irq_read(chan);
                axi_chan_irq_clear(chan, status);

                dev_vdbg(chip->dev, "%s %u IRQ status: 0x%08x\n",
                        axi_chan_name(chan), i, status);

                if (status & DWAXIDMAC_IRQ_ALL_ERR)
                        axi_chan_handle_err(chan, status);
                else if (status & DWAXIDMAC_IRQ_DMA_TRF)
                        axi_chan_block_xfer_complete(chan);
        }

        /* Re-enable interrupts */
        axi_dma_irq_enable(chip);

        return IRQ_HANDLED;
}

static int dma_chan_terminate_all(struct dma_chan *dchan)
{
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
        unsigned long flags;
        LIST_HEAD(head);

        spin_lock_irqsave(&chan->vc.lock, flags);

        axi_chan_disable(chan);

        vchan_get_all_descriptors(&chan->vc, &head);

        /*
         * As vchan_dma_desc_free_list can access to desc_allocated list
         * we need to call it in vc.lock context.
         */
        vchan_dma_desc_free_list(&chan->vc, &head);

        spin_unlock_irqrestore(&chan->vc.lock, flags);

        dev_vdbg(dchan2dev(dchan), "terminated: %s\n", axi_chan_name(chan));

        return 0;
}

static int dma_chan_pause(struct dma_chan *dchan)
{
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
        unsigned long flags;
        unsigned int timeout = 20; /* timeout iterations */
        u32 val;

        spin_lock_irqsave(&chan->vc.lock, flags);

        val = axi_dma_ioread32(chan->chip, DMAC_CHEN);
        val |= BIT(chan->id) << DMAC_CHAN_SUSP_SHIFT |
               BIT(chan->id) << DMAC_CHAN_SUSP_WE_SHIFT;
        axi_dma_iowrite32(chan->chip, DMAC_CHEN, val);

        do  {
                if (axi_chan_irq_read(chan) & DWAXIDMAC_IRQ_SUSPENDED)
                        break;

                udelay(2);
        } while (--timeout);

        axi_chan_irq_clear(chan, DWAXIDMAC_IRQ_SUSPENDED);

        chan->is_paused = true;

        spin_unlock_irqrestore(&chan->vc.lock, flags);

        return timeout ? 0 : -EAGAIN;
}

/* Called in chan locked context */
static inline void axi_chan_resume(struct axi_dma_chan *chan)
{
        u32 val;

        val = axi_dma_ioread32(chan->chip, DMAC_CHEN);
        val &= ~(BIT(chan->id) << DMAC_CHAN_SUSP_SHIFT);
        val |=  (BIT(chan->id) << DMAC_CHAN_SUSP_WE_SHIFT);
        axi_dma_iowrite32(chan->chip, DMAC_CHEN, val);

        chan->is_paused = false;
}

static int dma_chan_resume(struct dma_chan *dchan)
{
        struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
        unsigned long flags;

        spin_lock_irqsave(&chan->vc.lock, flags);

        if (chan->is_paused)
                axi_chan_resume(chan);

        spin_unlock_irqrestore(&chan->vc.lock, flags);

        return 0;
}

static int axi_dma_suspend(struct axi_dma_chip *chip)
{
        axi_dma_irq_disable(chip);
        axi_dma_disable(chip);

        clk_disable_unprepare(chip->core_clk);
        clk_disable_unprepare(chip->cfgr_clk);

        return 0;
}

static int axi_dma_resume(struct axi_dma_chip *chip)
{
        int ret;

        ret = clk_prepare_enable(chip->cfgr_clk);
        if (ret < 0)
                return ret;

        ret = clk_prepare_enable(chip->core_clk);
        if (ret < 0)
                return ret;

        axi_dma_enable(chip);
        axi_dma_irq_enable(chip);

        return 0;
}

static int __maybe_unused axi_dma_runtime_suspend(struct device *dev)
{
        struct axi_dma_chip *chip = dev_get_drvdata(dev);

        return axi_dma_suspend(chip);
}

static int __maybe_unused axi_dma_runtime_resume(struct device *dev)
{
        struct axi_dma_chip *chip = dev_get_drvdata(dev);

        return axi_dma_resume(chip);
}

static int parse_device_properties(struct axi_dma_chip *chip)
{
        struct device *dev = chip->dev;
        u32 tmp, carr[DMAC_MAX_CHANNELS];
        int ret;

        ret = device_property_read_u32(dev, "dma-channels", &tmp);
        if (ret)
                return ret;
        if (tmp == 0 || tmp > DMAC_MAX_CHANNELS)
                return -EINVAL;

        chip->dw->hdata->nr_channels = tmp;

        ret = device_property_read_u32(dev, "snps,dma-masters", &tmp);
        if (ret)
                return ret;
        if (tmp == 0 || tmp > DMAC_MAX_MASTERS)
                return -EINVAL;

        chip->dw->hdata->nr_masters = tmp;

        ret = device_property_read_u32(dev, "snps,data-width", &tmp);
        if (ret)
                return ret;
        if (tmp > DWAXIDMAC_TRANS_WIDTH_MAX)
                return -EINVAL;

        chip->dw->hdata->m_data_width = tmp;

        ret = device_property_read_u32_array(dev, "snps,block-size", carr,
                                             chip->dw->hdata->nr_channels);
        if (ret)
                return ret;
        for (tmp = 0; tmp < chip->dw->hdata->nr_channels; tmp++) {
                if (carr[tmp] == 0 || carr[tmp] > DMAC_MAX_BLK_SIZE)
                        return -EINVAL;

                chip->dw->hdata->block_size[tmp] = carr[tmp];
        }

        ret = device_property_read_u32_array(dev, "snps,priority", carr,
                                             chip->dw->hdata->nr_channels);
        if (ret)
                return ret;
        /* Priority value must be programmed within [0:nr_channels-1] range */
        for (tmp = 0; tmp < chip->dw->hdata->nr_channels; tmp++) {
                if (carr[tmp] >= chip->dw->hdata->nr_channels)
                        return -EINVAL;

                chip->dw->hdata->priority[tmp] = carr[tmp];
        }

        /* axi-max-burst-len is optional property */
        ret = device_property_read_u32(dev, "snps,axi-max-burst-len", &tmp);
        if (!ret) {
                if (tmp > DWAXIDMAC_ARWLEN_MAX + 1)
                        return -EINVAL;
                if (tmp < DWAXIDMAC_ARWLEN_MIN + 1)
                        return -EINVAL;

                chip->dw->hdata->restrict_axi_burst_len = true;
                chip->dw->hdata->axi_rw_burst_len = tmp - 1;
        }

        return 0;
}

static int dw_probe(struct platform_device *pdev)
{
        struct axi_dma_chip *chip;
        struct resource *mem;
        struct dw_axi_dma *dw;
        struct dw_axi_dma_hcfg *hdata;
        u32 i;
        int ret;

        chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
        if (!chip)
                return -ENOMEM;

        dw = devm_kzalloc(&pdev->dev, sizeof(*dw), GFP_KERNEL);
        if (!dw)
                return -ENOMEM;

        hdata = devm_kzalloc(&pdev->dev, sizeof(*hdata), GFP_KERNEL);
        if (!hdata)
                return -ENOMEM;

        chip->dw = dw;
        chip->dev = &pdev->dev;
        chip->dw->hdata = hdata;

        chip->irq = platform_get_irq(pdev, 0);
        if (chip->irq < 0)
                return chip->irq;

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        chip->regs = devm_ioremap_resource(chip->dev, mem);
        if (IS_ERR(chip->regs))
                return PTR_ERR(chip->regs);

        chip->core_clk = devm_clk_get(chip->dev, "core-clk");
        if (IS_ERR(chip->core_clk))
                return PTR_ERR(chip->core_clk);

        chip->cfgr_clk = devm_clk_get(chip->dev, "cfgr-clk");
        if (IS_ERR(chip->cfgr_clk))
                return PTR_ERR(chip->cfgr_clk);

        ret = parse_device_properties(chip);
        if (ret)
                return ret;

        dw->chan = devm_kcalloc(chip->dev, hdata->nr_channels,
                                sizeof(*dw->chan), GFP_KERNEL);
        if (!dw->chan)
                return -ENOMEM;

        ret = devm_request_irq(chip->dev, chip->irq, dw_axi_dma_interrupt,
                               IRQF_SHARED, KBUILD_MODNAME, chip);
        if (ret)
                return ret;

        /* Lli address must be aligned to a 64-byte boundary */
        dw->desc_pool = dmam_pool_create(KBUILD_MODNAME, chip->dev,
                                         sizeof(struct axi_dma_desc), 64, 0);
        if (!dw->desc_pool) {
                dev_err(chip->dev, "No memory for descriptors dma pool\n");
                return -ENOMEM;
        }

        INIT_LIST_HEAD(&dw->dma.channels);
        for (i = 0; i < hdata->nr_channels; i++) {
                struct axi_dma_chan *chan = &dw->chan[i];

                chan->chip = chip;
                chan->id = i;
                chan->chan_regs = chip->regs + COMMON_REG_LEN + i * CHAN_REG_LEN;
                atomic_set(&chan->descs_allocated, 0);

                chan->vc.desc_free = vchan_desc_put;
                vchan_init(&chan->vc, &dw->dma);
        }

        /* Set capabilities */
        dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);

        /* DMA capabilities */
        dw->dma.chancnt = hdata->nr_channels;
        dw->dma.src_addr_widths = AXI_DMA_BUSWIDTHS;
        dw->dma.dst_addr_widths = AXI_DMA_BUSWIDTHS;
        dw->dma.directions = BIT(DMA_MEM_TO_MEM);
        dw->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;

        dw->dma.dev = chip->dev;
        dw->dma.device_tx_status = dma_chan_tx_status;
        dw->dma.device_issue_pending = dma_chan_issue_pending;
        dw->dma.device_terminate_all = dma_chan_terminate_all;
        dw->dma.device_pause = dma_chan_pause;
        dw->dma.device_resume = dma_chan_resume;

        dw->dma.device_alloc_chan_resources = dma_chan_alloc_chan_resources;
        dw->dma.device_free_chan_resources = dma_chan_free_chan_resources;

        dw->dma.device_prep_dma_memcpy = dma_chan_prep_dma_memcpy;

        platform_set_drvdata(pdev, chip);

        pm_runtime_enable(chip->dev);

        /*
         * We can't just call pm_runtime_get here instead of
         * pm_runtime_get_noresume + axi_dma_resume because we need
         * driver to work also without Runtime PM.
         */
        pm_runtime_get_noresume(chip->dev);
        ret = axi_dma_resume(chip);
        if (ret < 0)
                goto err_pm_disable;

        axi_dma_hw_init(chip);

        pm_runtime_put(chip->dev);

        ret = dma_async_device_register(&dw->dma);
        if (ret)
                goto err_pm_disable;

        dev_info(chip->dev, "DesignWare AXI DMA Controller, %d channels\n",
                 dw->hdata->nr_channels);

        return 0;

err_pm_disable:
        pm_runtime_disable(chip->dev);

        return ret;
}

static int dw_remove(struct platform_device *pdev)
{
        struct axi_dma_chip *chip = platform_get_drvdata(pdev);
        struct dw_axi_dma *dw = chip->dw;
        struct axi_dma_chan *chan, *_chan;
        u32 i;

        /* Enable clk before accessing to registers */
        clk_prepare_enable(chip->cfgr_clk);
        clk_prepare_enable(chip->core_clk);
        axi_dma_irq_disable(chip);
        for (i = 0; i < dw->hdata->nr_channels; i++) {
                axi_chan_disable(&chip->dw->chan[i]);
                axi_chan_irq_disable(&chip->dw->chan[i], DWAXIDMAC_IRQ_ALL);
        }
        axi_dma_disable(chip);

        pm_runtime_disable(chip->dev);
        axi_dma_suspend(chip);

        devm_free_irq(chip->dev, chip->irq, chip);

        list_for_each_entry_safe(chan, _chan, &dw->dma.channels,
                        vc.chan.device_node) {
                list_del(&chan->vc.chan.device_node);
                tasklet_kill(&chan->vc.task);
        }

        dma_async_device_unregister(&dw->dma);

        return 0;
}

static const struct dev_pm_ops dw_axi_dma_pm_ops = {
        SET_RUNTIME_PM_OPS(axi_dma_runtime_suspend, axi_dma_runtime_resume, NULL)
};

static const struct of_device_id dw_dma_of_id_table[] = {
        { .compatible = "snps,axi-dma-1.01a" },
        {}
};
MODULE_DEVICE_TABLE(of, dw_dma_of_id_table);

static struct platform_driver dw_driver = {
        .probe          = dw_probe,
        .remove         = dw_remove,
        .driver = {
                .name   = KBUILD_MODNAME,
                .of_match_table = of_match_ptr(dw_dma_of_id_table),

                .pm = &dw_axi_dma_pm_ops,
        },
};
module_platform_driver(dw_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Synopsys DesignWare AXI DMA Controller platform driver");
MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>");