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    SubjectRe: [PATCH] dma: Add Xilinx AXI Video Direct Memory Access Engine driver support
    On 01/16/2014 12:53 PM, Srikanth Thokala wrote:
    > This is the driver for the AXI Video Direct Memory Access (AXI
    > VDMA) core, which is a soft Xilinx IP core that provides high-
    > bandwidth direct memory access between memory and AXI4-Stream
    > type video target peripherals. The core provides efficient two
    > dimensional DMA operations with independent asynchronous read
    > and write channel operation.
    >

    [snip]

    > +/**
    > + * xilinx_vdma_start - Start VDMA channel
    > + * @chan: Driver specific VDMA channel
    > + */
    > +static void xilinx_vdma_start(struct xilinx_vdma_chan *chan)
    > +{
    > + int loop = XILINX_VDMA_LOOP_COUNT + 1;
    > +
    > + vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RUNSTOP);
    > +
    > + /* Wait for the hardware to start */
    > + while (loop)


    loop-- ?

    Philip

    > + if (!(vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
    > + XILINX_VDMA_DMASR_HALTED))
    > + break;
    > +
    > + if (!loop) {
    > + dev_err(chan->dev, "Cannot start channel %p: %x\n",
    > + chan, vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
    > +
    > + chan->err = true;
    > + }
    > +
    > + return;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_start_transfer - Starts VDMA transfer
    > + * @chan: Driver specific channel struct pointer
    > + */
    > +static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan)
    > +{
    > + struct xilinx_vdma_config *config = &chan->config;
    > + struct xilinx_vdma_tx_descriptor *desc;
    > + unsigned long flags;
    > + u32 reg;
    > + struct xilinx_vdma_tx_segment *head, *tail = NULL;
    > +
    > + if (chan->err)
    > + return;
    > +
    > + spin_lock_irqsave(&chan->lock, flags);
    > +
    > + /* There's already an active descriptor, bail out. */
    > + if (chan->active_desc)
    > + goto out_unlock;
    > +
    > + if (list_empty(&chan->pending_list))
    > + goto out_unlock;
    > +
    > + desc = list_first_entry(&chan->pending_list,
    > + struct xilinx_vdma_tx_descriptor, node);
    > +
    > + /* If it is SG mode and hardware is busy, cannot submit */
    > + if (chan->has_sg && xilinx_vdma_is_running(chan) &&
    > + !xilinx_vdma_is_idle(chan)) {
    > + dev_dbg(chan->dev, "DMA controller still busy\n");
    > + goto out_unlock;
    > + }
    > +
    > + if (chan->err)
    > + goto out_unlock;
    > +
    > + /*
    > + * If hardware is idle, then all descriptors on the running lists are
    > + * done, start new transfers
    > + */
    > + if (chan->has_sg) {
    > + head = list_first_entry(&desc->segments,
    > + struct xilinx_vdma_tx_segment, node);
    > + tail = list_entry(desc->segments.prev,
    > + struct xilinx_vdma_tx_segment, node);
    > +
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_CURDESC, head->phys);
    > + }
    > +
    > + /* Configure the hardware using info in the config structure */
    > + reg = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR);
    > +
    > + if (config->frm_cnt_en)
    > + reg |= XILINX_VDMA_DMACR_FRAMECNT_EN;
    > + else
    > + reg &= ~XILINX_VDMA_DMACR_FRAMECNT_EN;
    > +
    > + /*
    > + * With SG, start with circular mode, so that BDs can be fetched.
    > + * In direct register mode, if not parking, enable circular mode
    > + */
    > + if (chan->has_sg || !config->park)
    > + reg |= XILINX_VDMA_DMACR_CIRC_EN;
    > +
    > + if (config->park)
    > + reg &= ~XILINX_VDMA_DMACR_CIRC_EN;
    > +
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, reg);
    > +
    > + if (config->park && (config->park_frm >= 0) &&
    > + (config->park_frm < chan->num_frms)) {
    > + if (chan->direction == DMA_MEM_TO_DEV)
    > + vdma_write(chan, XILINX_VDMA_REG_PARK_PTR,
    > + config->park_frm <<
    > + XILINX_VDMA_PARK_PTR_RD_REF_SHIFT);
    > + else
    > + vdma_write(chan, XILINX_VDMA_REG_PARK_PTR,
    > + config->park_frm <<
    > + XILINX_VDMA_PARK_PTR_WR_REF_SHIFT);
    > + }
    > +
    > + /* Start the hardware */
    > + xilinx_vdma_start(chan);
    > +
    > + if (chan->err)
    > + goto out_unlock;
    > +
    > + /* Start the transfer */
    > + if (chan->has_sg) {
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_TAILDESC, tail->phys);
    > + } else {
    > + struct xilinx_vdma_tx_segment *segment;
    > + int i = 0;
    > +
    > + list_for_each_entry(segment, &desc->segments, node)
    > + vdma_desc_write(chan,
    > + XILINX_VDMA_REG_START_ADDRESS(i++),
    > + segment->hw.buf_addr);
    > +
    > + vdma_desc_write(chan, XILINX_VDMA_REG_HSIZE, config->hsize);
    > + vdma_desc_write(chan, XILINX_VDMA_REG_FRMDLY_STRIDE,
    > + (config->frm_dly <<
    > + XILINX_VDMA_FRMDLY_STRIDE_FRMDLY_SHIFT) |
    > + (config->stride <<
    > + XILINX_VDMA_FRMDLY_STRIDE_STRIDE_SHIFT));
    > + vdma_desc_write(chan, XILINX_VDMA_REG_VSIZE, config->vsize);
    > + }
    > +
    > + list_del(&desc->node);
    > + chan->active_desc = desc;
    > +
    > +out_unlock:
    > + spin_unlock_irqrestore(&chan->lock, flags);
    > +}
    > +
    > +/**
    > + * xilinx_vdma_issue_pending - Issue pending transactions
    > + * @dchan: DMA channel
    > + */
    > +static void xilinx_vdma_issue_pending(struct dma_chan *dchan)
    > +{
    > + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
    > +
    > + xilinx_vdma_start_transfer(chan);
    > +}
    > +
    > +/**
    > + * xilinx_vdma_complete_descriptor - Mark the active descriptor as complete
    > + * @chan : xilinx DMA channel
    > + *
    > + * CONTEXT: hardirq
    > + */
    > +static void xilinx_vdma_complete_descriptor(struct xilinx_vdma_chan *chan)
    > +{
    > + struct xilinx_vdma_tx_descriptor *desc;
    > + unsigned long flags;
    > +
    > + spin_lock_irqsave(&chan->lock, flags);
    > +
    > + desc = chan->active_desc;
    > + if (!desc) {
    > + dev_dbg(chan->dev, "no running descriptors\n");
    > + goto out_unlock;
    > + }
    > +
    > + list_add_tail(&desc->node, &chan->done_list);
    > +
    > + /* Update the completed cookie and reset the active descriptor. */
    > + chan->completed_cookie = desc->async_tx.cookie;
    > + chan->active_desc = NULL;
    > +
    > +out_unlock:
    > + spin_unlock_irqrestore(&chan->lock, flags);
    > +}
    > +
    > +/**
    > + * xilinx_vdma_reset - Reset VDMA channel
    > + * @chan: Driver specific VDMA channel
    > + *
    > + * Return: '0' on success and failure value on error
    > + */
    > +static int xilinx_vdma_reset(struct xilinx_vdma_chan *chan)
    > +{
    > + int loop = XILINX_VDMA_LOOP_COUNT + 1;
    > + u32 tmp;
    > +
    > + vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RESET);
    > +
    > + tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
    > + XILINX_VDMA_DMACR_RESET;
    > +
    > + /* Wait for the hardware to finish reset */
    > + while (loop-- && tmp)
    > + tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
    > + XILINX_VDMA_DMACR_RESET;
    > +
    > + if (!loop) {
    > + dev_err(chan->dev, "reset timeout, cr %x, sr %x\n",
    > + vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR),
    > + vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
    > + return -ETIMEDOUT;
    > + }
    > +
    > + chan->err = false;
    > +
    > + return 0;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_chan_reset - Reset VDMA channel and enable interrupts
    > + * @chan: Driver specific VDMA channel
    > + *
    > + * Return: '0' on success and failure value on error
    > + */
    > +static int xilinx_vdma_chan_reset(struct xilinx_vdma_chan *chan)
    > +{
    > + int err;
    > +
    > + /* Reset VDMA */
    > + err = xilinx_vdma_reset(chan);
    > + if (err)
    > + return err;
    > +
    > + /* Enable interrupts */
    > + vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR,
    > + XILINX_VDMA_DMAXR_ALL_IRQ_MASK);
    > +
    > + return 0;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_irq_handler - VDMA Interrupt handler
    > + * @irq: IRQ number
    > + * @data: Pointer to the Xilinx VDMA channel structure
    > + *
    > + * Return: IRQ_HANDLED/IRQ_NONE
    > + */
    > +static irqreturn_t xilinx_vdma_irq_handler(int irq, void *data)
    > +{
    > + struct xilinx_vdma_chan *chan = data;
    > + u32 status;
    > +
    > + /* Read the status and ack the interrupts. */
    > + status = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR);
    > + if (!(status & XILINX_VDMA_DMAXR_ALL_IRQ_MASK))
    > + return IRQ_NONE;
    > +
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMASR,
    > + status & XILINX_VDMA_DMAXR_ALL_IRQ_MASK);
    > +
    > + if (status & XILINX_VDMA_DMASR_ERR_IRQ) {
    > + /*
    > + * An error occurred. If C_FLUSH_ON_FSYNC is enabled and the
    > + * error is recoverable, ignore it. Otherwise flag the error.
    > + *
    > + * Only recoverable errors can be cleared in the DMASR register,
    > + * make sure not to write to other error bits to 1.
    > + */
    > + u32 errors = status & XILINX_VDMA_DMASR_ALL_ERR_MASK;
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMASR,
    > + errors & XILINX_VDMA_DMASR_ERR_RECOVER_MASK);
    > +
    > + if (!chan->flush_on_fsync ||
    > + (errors & ~XILINX_VDMA_DMASR_ERR_RECOVER_MASK)) {
    > + dev_err(chan->dev,
    > + "Channel %p has errors %x, cdr %x tdr %x\n",
    > + chan, errors,
    > + vdma_ctrl_read(chan, XILINX_VDMA_REG_CURDESC),
    > + vdma_ctrl_read(chan, XILINX_VDMA_REG_TAILDESC));
    > + chan->err = true;
    > + }
    > + }
    > +
    > + if (status & XILINX_VDMA_DMASR_DLY_CNT_IRQ) {
    > + /*
    > + * Device takes too long to do the transfer when user requires
    > + * responsiveness.
    > + */
    > + dev_dbg(chan->dev, "Inter-packet latency too long\n");
    > + }
    > +
    > + if (status & XILINX_VDMA_DMASR_FRM_CNT_IRQ) {
    > + xilinx_vdma_complete_descriptor(chan);
    > + xilinx_vdma_start_transfer(chan);
    > + }
    > +
    > + tasklet_schedule(&chan->tasklet);
    > + return IRQ_HANDLED;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_tx_submit - Submit DMA transaction
    > + * @tx: Async transaction descriptor
    > + *
    > + * Return: cookie value on success and failure value on error
    > + */
    > +static dma_cookie_t xilinx_vdma_tx_submit(struct dma_async_tx_descriptor *tx)
    > +{
    > + struct xilinx_vdma_tx_descriptor *desc = to_vdma_tx_descriptor(tx);
    > + struct xilinx_vdma_chan *chan = to_xilinx_chan(tx->chan);
    > + struct xilinx_vdma_tx_segment *segment;
    > + dma_cookie_t cookie;
    > + unsigned long flags;
    > + int err;
    > +
    > + if (chan->err) {
    > + /*
    > + * If reset fails, need to hard reset the system.
    > + * Channel is no longer functional
    > + */
    > + err = xilinx_vdma_chan_reset(chan);
    > + if (err < 0)
    > + return err;
    > + }
    > +
    > + spin_lock_irqsave(&chan->lock, flags);
    > +
    > + /* Assign cookies to all of the segments that make up this transaction.
    > + * Use the cookie of the last segment as the transaction cookie.
    > + */
    > + cookie = chan->cookie;
    > +
    > + list_for_each_entry(segment, &desc->segments, node) {
    > + if (cookie < DMA_MAX_COOKIE)
    > + cookie++;
    > + else
    > + cookie = DMA_MIN_COOKIE;
    > +
    > + segment->cookie = cookie;
    > + }
    > +
    > + tx->cookie = cookie;
    > + chan->cookie = cookie;
    > +
    > + /* Append the transaction to the pending transactions queue. */
    > + list_add_tail(&desc->node, &chan->pending_list);
    > +
    > + spin_unlock_irqrestore(&chan->lock, flags);
    > +
    > + return cookie;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_prep_slave_sg - prepare a descriptor for a DMA_SLAVE transaction
    > + * @dchan: DMA channel
    > + * @sgl: scatterlist to transfer to/from
    > + * @sg_len: number of entries in @sgl
    > + * @dir: DMA direction
    > + * @flags: transfer ack flags
    > + * @context: unused
    > + *
    > + * Return: Async transaction descriptor on success and NULL on failure
    > + */
    > +static struct dma_async_tx_descriptor *
    > +xilinx_vdma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
    > + unsigned int sg_len, enum dma_transfer_direction dir,
    > + unsigned long flags, void *context)
    > +{
    > + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
    > + struct xilinx_vdma_tx_descriptor *desc;
    > + struct xilinx_vdma_tx_segment *segment;
    > + struct xilinx_vdma_tx_segment *prev = NULL;
    > + struct scatterlist *sg;
    > + int i;
    > +
    > + if (chan->direction != dir || sg_len == 0)
    > + return NULL;
    > +
    > + /* Enforce one sg entry for one frame. */
    > + if (sg_len != chan->num_frms) {
    > + dev_err(chan->dev,
    > + "number of entries %d not the same as num stores %d\n",
    > + sg_len, chan->num_frms);
    > + return NULL;
    > + }
    > +
    > + /* Allocate a transaction descriptor. */
    > + desc = xilinx_vdma_alloc_tx_descriptor(chan);
    > + if (!desc)
    > + return NULL;
    > +
    > + dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
    > + desc->async_tx.tx_submit = xilinx_vdma_tx_submit;
    > + desc->async_tx.cookie = 0;
    > + async_tx_ack(&desc->async_tx);
    > +
    > + /* Build the list of transaction segments. */
    > + for_each_sg(sgl, sg, sg_len, i) {
    > + struct xilinx_vdma_desc_hw *hw;
    > +
    > + /* Allocate the link descriptor from DMA pool */
    > + segment = xilinx_vdma_alloc_tx_segment(chan);
    > + if (!segment)
    > + goto error;
    > +
    > + /* Fill in the hardware descriptor */
    > + hw = &segment->hw;
    > + hw->buf_addr = sg_dma_address(sg);
    > + hw->vsize = chan->config.vsize;
    > + hw->hsize = chan->config.hsize;
    > + hw->stride = (chan->config.frm_dly <<
    > + XILINX_VDMA_FRMDLY_STRIDE_FRMDLY_SHIFT) |
    > + (chan->config.stride <<
    > + XILINX_VDMA_FRMDLY_STRIDE_STRIDE_SHIFT);
    > + if (prev)
    > + prev->hw.next_desc = segment->phys;
    > +
    > + /* Insert the segment into the descriptor segments list. */
    > + list_add_tail(&segment->node, &desc->segments);
    > +
    > + prev = segment;
    > + }
    > +
    > + /* Link the last hardware descriptor with the first. */
    > + segment = list_first_entry(&desc->segments,
    > + struct xilinx_vdma_tx_segment, node);
    > + prev->hw.next_desc = segment->phys;
    > +
    > + return &desc->async_tx;
    > +
    > +error:
    > + xilinx_vdma_free_tx_descriptor(chan, desc);
    > + return NULL;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_terminate_all - Halt the channel and free descriptors
    > + * @chan: Driver specific VDMA Channel pointer
    > + */
    > +static void xilinx_vdma_terminate_all(struct xilinx_vdma_chan *chan)
    > +{
    > + /* Halt the DMA engine */
    > + xilinx_vdma_halt(chan);
    > +
    > + /* Remove and free all of the descriptors in the lists */
    > + xilinx_vdma_free_descriptors(chan);
    > +}
    > +
    > +/**
    > + * xilinx_vdma_slave_config - Configure VDMA channel
    > + * Run-time configuration for Axi VDMA, supports:
    > + * . halt the channel
    > + * . configure interrupt coalescing and inter-packet delay threshold
    > + * . start/stop parking
    > + * . enable genlock
    > + * . set transfer information using config struct
    > + *
    > + * @chan: Driver specific VDMA Channel pointer
    > + * @cfg: Channel configuration pointer
    > + *
    > + * Return: '0' on success and failure value on error
    > + */
    > +static int xilinx_vdma_slave_config(struct xilinx_vdma_chan *chan,
    > + struct xilinx_vdma_config *cfg)
    > +{
    > + u32 dmacr;
    > +
    > + if (cfg->reset)
    > + return xilinx_vdma_chan_reset(chan);
    > +
    > + dmacr = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR);
    > +
    > + /* If vsize is -1, it is park-related operations */
    > + if (cfg->vsize == -1) {
    > + if (cfg->park)
    > + dmacr &= ~XILINX_VDMA_DMACR_CIRC_EN;
    > + else
    > + dmacr |= XILINX_VDMA_DMACR_CIRC_EN;
    > +
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, dmacr);
    > + return 0;
    > + }
    > +
    > + /* If hsize is -1, it is interrupt threshold settings */
    > + if (cfg->hsize == -1) {
    > + if (cfg->coalesc <= XILINX_VDMA_DMACR_FRAME_COUNT_MAX) {
    > + dmacr &= ~XILINX_VDMA_DMACR_FRAME_COUNT_MASK;
    > + dmacr |= cfg->coalesc <<
    > + XILINX_VDMA_DMACR_FRAME_COUNT_SHIFT;
    > + chan->config.coalesc = cfg->coalesc;
    > + }
    > +
    > + if (cfg->delay <= XILINX_VDMA_DMACR_DELAY_MAX) {
    > + dmacr &= ~XILINX_VDMA_DMACR_DELAY_MASK;
    > + dmacr |= cfg->delay << XILINX_VDMA_DMACR_DELAY_SHIFT;
    > + chan->config.delay = cfg->delay;
    > + }
    > +
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, dmacr);
    > + return 0;
    > + }
    > +
    > + /* Transfer information */
    > + chan->config.vsize = cfg->vsize;
    > + chan->config.hsize = cfg->hsize;
    > + chan->config.stride = cfg->stride;
    > + chan->config.frm_dly = cfg->frm_dly;
    > + chan->config.park = cfg->park;
    > +
    > + /* genlock settings */
    > + chan->config.gen_lock = cfg->gen_lock;
    > + chan->config.master = cfg->master;
    > +
    > + if (cfg->gen_lock && chan->genlock) {
    > + dmacr |= XILINX_VDMA_DMACR_GENLOCK_EN;
    > + dmacr |= cfg->master << XILINX_VDMA_DMACR_MASTER_SHIFT;
    > + }
    > +
    > + chan->config.frm_cnt_en = cfg->frm_cnt_en;
    > + if (cfg->park)
    > + chan->config.park_frm = cfg->park_frm;
    > + else
    > + chan->config.park_frm = -1;
    > +
    > + chan->config.coalesc = cfg->coalesc;
    > + chan->config.delay = cfg->delay;
    > + if (cfg->coalesc <= XILINX_VDMA_DMACR_FRAME_COUNT_MAX) {
    > + dmacr |= cfg->coalesc << XILINX_VDMA_DMACR_FRAME_COUNT_SHIFT;
    > + chan->config.coalesc = cfg->coalesc;
    > + }
    > +
    > + if (cfg->delay <= XILINX_VDMA_DMACR_DELAY_MAX) {
    > + dmacr |= cfg->delay << XILINX_VDMA_DMACR_DELAY_SHIFT;
    > + chan->config.delay = cfg->delay;
    > + }
    > +
    > + /* FSync Source selection */
    > + dmacr &= ~XILINX_VDMA_DMACR_FSYNCSRC_MASK;
    > + dmacr |= cfg->ext_fsync << XILINX_VDMA_DMACR_FSYNCSRC_SHIFT;
    > +
    > + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, dmacr);
    > + return 0;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_device_control - Configure DMA channel of the device
    > + * @dchan: DMA Channel pointer
    > + * @cmd: DMA control command
    > + * @arg: Channel configuration
    > + *
    > + * Return: '0' on success and failure value on error
    > + */
    > +static int xilinx_vdma_device_control(struct dma_chan *dchan,
    > + enum dma_ctrl_cmd cmd, unsigned long arg)
    > +{
    > + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
    > +
    > + switch (cmd) {
    > + case DMA_TERMINATE_ALL:
    > + xilinx_vdma_terminate_all(chan);
    > + return 0;
    > + case DMA_SLAVE_CONFIG:
    > + return xilinx_vdma_slave_config(chan,
    > + (struct xilinx_vdma_config *)arg);
    > + default:
    > + return -ENXIO;
    > + }
    > +}
    > +
    > +/* -----------------------------------------------------------------------------
    > + * Probe and remove
    > + */
    > +
    > +/**
    > + * xilinx_vdma_chan_remove - Per Channel remove function
    > + * @chan: Driver specific VDMA channel
    > + */
    > +static void xilinx_vdma_chan_remove(struct xilinx_vdma_chan *chan)
    > +{
    > + /* Disable all interrupts */
    > + vdma_ctrl_clr(chan, XILINX_VDMA_REG_DMACR,
    > + XILINX_VDMA_DMAXR_ALL_IRQ_MASK);
    > +
    > + list_del(&chan->common.device_node);
    > +}
    > +
    > +/**
    > + * xilinx_vdma_chan_probe - Per Channel Probing
    > + * It get channel features from the device tree entry and
    > + * initialize special channel handling routines
    > + *
    > + * @xdev: Driver specific device structure
    > + * @node: Device node
    > + *
    > + * Return: '0' on success and failure value on error
    > + */
    > +static int xilinx_vdma_chan_probe(struct xilinx_vdma_device *xdev,
    > + struct device_node *node)
    > +{
    > + struct xilinx_vdma_chan *chan;
    > + bool has_dre = false;
    > + u32 device_id;
    > + u32 value;
    > + int err;
    > +
    > + /* Allocate and initialize the channel structure */
    > + chan = devm_kzalloc(xdev->dev, sizeof(*chan), GFP_KERNEL);
    > + if (!chan)
    > + return -ENOMEM;
    > +
    > + chan->dev = xdev->dev;
    > + chan->xdev = xdev;
    > + chan->has_sg = xdev->has_sg;
    > +
    > + spin_lock_init(&chan->lock);
    > + INIT_LIST_HEAD(&chan->pending_list);
    > + INIT_LIST_HEAD(&chan->done_list);
    > +
    > + /* Retrieve the channel properties from the device tree */
    > + has_dre = of_property_read_bool(node, "xlnx,include-dre");
    > +
    > + chan->genlock = of_property_read_bool(node, "xlnx,genlock-mode");
    > +
    > + err = of_property_read_u32(node, "xlnx,datawidth", &value);
    > + if (!err) {
    > + u32 width = value >> 3; /* Convert bits to bytes */
    > +
    > + /* If data width is greater than 8 bytes, DRE is not in hw */
    > + if (width > 8)
    > + has_dre = false;
    > +
    > + if (!has_dre)
    > + xdev->common.copy_align = fls(width - 1);
    > + }
    > +
    > + err = of_property_read_u32(node, "xlnx,device-id", &device_id);
    > + if (err < 0) {
    > + dev_err(xdev->dev, "missing xlnx,device-id property\n");
    > + return err;
    > + }
    > +
    > + if (of_device_is_compatible(node, "xlnx,axi-vdma-mm2s-channel")) {
    > + chan->direction = DMA_MEM_TO_DEV;
    > + chan->id = 0;
    > +
    > + chan->ctrl_offset = XILINX_VDMA_MM2S_CTRL_OFFSET;
    > + chan->desc_offset = XILINX_VDMA_MM2S_DESC_OFFSET;
    > +
    > + if (xdev->flush_on_fsync == XILINX_VDMA_FLUSH_BOTH ||
    > + xdev->flush_on_fsync == XILINX_VDMA_FLUSH_MM2S)
    > + chan->flush_on_fsync = true;
    > + } else if (of_device_is_compatible(node,
    > + "xlnx,axi-vdma-s2mm-channel")) {
    > + chan->direction = DMA_DEV_TO_MEM;
    > + chan->id = 1;
    > +
    > + chan->ctrl_offset = XILINX_VDMA_S2MM_CTRL_OFFSET;
    > + chan->desc_offset = XILINX_VDMA_S2MM_DESC_OFFSET;
    > +
    > + if (xdev->flush_on_fsync == XILINX_VDMA_FLUSH_BOTH ||
    > + xdev->flush_on_fsync == XILINX_VDMA_FLUSH_S2MM)
    > + chan->flush_on_fsync = true;
    > + } else {
    > + dev_err(xdev->dev, "Invalid channel compatible node\n");
    > + return -EINVAL;
    > + }
    > +
    > + /*
    > + * Used by DMA clients who doesnt have a device node and can request
    > + * the channel by passing this as a filter to 'dma_request_channel()'.
    > + */
    > + chan->private = (chan->direction & 0xff) |
    > + XILINX_DMA_IP_VDMA |
    > + (device_id << XILINX_DMA_DEVICE_ID_SHIFT);
    > +
    > + /* Request the interrupt */
    > + chan->irq = irq_of_parse_and_map(node, 0);
    > + err = devm_request_irq(xdev->dev, chan->irq, xilinx_vdma_irq_handler,
    > + IRQF_SHARED, "xilinx-vdma-controller", chan);
    > + if (err) {
    > + dev_err(xdev->dev, "unable to request IRQ\n");
    > + return err;
    > + }
    > +
    > + /* Initialize the DMA channel and add it to the DMA engine channels
    > + * list.
    > + */
    > + chan->common.device = &xdev->common;
    > + chan->common.private = (void *)&(chan->private);
    > +
    > + list_add_tail(&chan->common.device_node, &xdev->common.channels);
    > + xdev->chan[chan->id] = chan;
    > +
    > + /* Reset the channel */
    > + err = xilinx_vdma_chan_reset(chan);
    > + if (err < 0) {
    > + dev_err(xdev->dev, "Reset channel failed\n");
    > + return err;
    > + }
    > +
    > + return 0;
    > +}
    > +
    > +/**
    > + * struct of_dma_filter_xilinx_args - Channel filter args
    > + * @dev: DMA device structure
    > + * @chan_id: Channel id
    > + */
    > +struct of_dma_filter_xilinx_args {
    > + struct dma_device *dev;
    > + u32 chan_id;
    > +};
    > +
    > +/**
    > + * xilinx_vdma_dt_filter - VDMA channel filter function
    > + * @chan: DMA channel pointer
    > + * @param: Filter match value
    > + *
    > + * Return: true/false based on the result
    > + */
    > +static bool xilinx_vdma_dt_filter(struct dma_chan *chan, void *param)
    > +{
    > + struct of_dma_filter_xilinx_args *args = param;
    > +
    > + return chan->device == args->dev && chan->chan_id == args->chan_id;
    > +}
    > +
    > +/**
    > + * of_dma_xilinx_xlate - Translation function
    > + * @dma_spec: Pointer to DMA specifier as found in the device tree
    > + * @ofdma: Pointer to DMA controller data
    > + *
    > + * Return: DMA channel pointer on success and NULL on error
    > + */
    > +static struct dma_chan *of_dma_xilinx_xlate(struct of_phandle_args *dma_spec,
    > + struct of_dma *ofdma)
    > +{
    > + struct of_dma_filter_xilinx_args args;
    > + dma_cap_mask_t cap;
    > +
    > + args.dev = ofdma->of_dma_data;
    > + if (!args.dev)
    > + return NULL;
    > +
    > + if (dma_spec->args_count != 1)
    > + return NULL;
    > +
    > + dma_cap_zero(cap);
    > + dma_cap_set(DMA_SLAVE, cap);
    > +
    > + args.chan_id = dma_spec->args[0];
    > +
    > + return dma_request_channel(cap, xilinx_vdma_dt_filter, &args);
    > +}
    > +
    > +/**
    > + * xilinx_vdma_probe - Driver probe function
    > + * @pdev: Pointer to the platform_device structure
    > + *
    > + * Return: '0' on success and failure value on error
    > + */
    > +static int xilinx_vdma_probe(struct platform_device *pdev)
    > +{
    > + struct device_node *node = pdev->dev.of_node;
    > + struct xilinx_vdma_device *xdev;
    > + struct device_node *child;
    > + struct resource *io;
    > + u32 num_frames;
    > + int i, err;
    > +
    > + dev_info(&pdev->dev, "Probing xilinx axi vdma engine\n");
    > +
    > + /* Allocate and initialize the DMA engine structure */
    > + xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
    > + if (!xdev)
    > + return -ENOMEM;
    > +
    > + xdev->dev = &pdev->dev;
    > +
    > + /* Request and map I/O memory */
    > + io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    > + xdev->regs = devm_ioremap_resource(&pdev->dev, io);
    > + if (IS_ERR(xdev->regs))
    > + return PTR_ERR(xdev->regs);
    > +
    > + /* Retrieve the DMA engine properties from the device tree */
    > + xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg");
    > +
    > + err = of_property_read_u32(node, "xlnx,num-fstores", &num_frames);
    > + if (err < 0) {
    > + dev_err(xdev->dev, "missing xlnx,num-fstores property\n");
    > + return err;
    > + }
    > +
    > + of_property_read_u32(node, "xlnx,flush-fsync", &xdev->flush_on_fsync);
    > +
    > + /* Initialize the DMA engine */
    > + xdev->common.dev = &pdev->dev;
    > +
    > + INIT_LIST_HEAD(&xdev->common.channels);
    > + dma_cap_set(DMA_SLAVE, xdev->common.cap_mask);
    > + dma_cap_set(DMA_PRIVATE, xdev->common.cap_mask);
    > +
    > + xdev->common.device_alloc_chan_resources =
    > + xilinx_vdma_alloc_chan_resources;
    > + xdev->common.device_free_chan_resources =
    > + xilinx_vdma_free_chan_resources;
    > + xdev->common.device_prep_slave_sg = xilinx_vdma_prep_slave_sg;
    > + xdev->common.device_control = xilinx_vdma_device_control;
    > + xdev->common.device_tx_status = xilinx_vdma_tx_status;
    > + xdev->common.device_issue_pending = xilinx_vdma_issue_pending;
    > +
    > + platform_set_drvdata(pdev, xdev);
    > +
    > + /* Initialize the channels */
    > + for_each_child_of_node(node, child) {
    > + err = xilinx_vdma_chan_probe(xdev, child);
    > + if (err < 0)
    > + goto error;
    > + }
    > +
    > + for (i = 0; i < XILINX_VDMA_MAX_CHANS_PER_DEVICE; i++) {
    > + if (xdev->chan[i])
    > + xdev->chan[i]->num_frms = num_frames;
    > + }
    > +
    > + /* Register the DMA engine with the core */
    > + dma_async_device_register(&xdev->common);
    > +
    > + err = of_dma_controller_register(node, of_dma_xilinx_xlate,
    > + &xdev->common);
    > + if (err < 0)
    > + dev_err(&pdev->dev, "Unable to register DMA to DT\n");
    > +
    > + return 0;
    > +
    > +error:
    > + for (i = 0; i < XILINX_VDMA_MAX_CHANS_PER_DEVICE; i++) {
    > + if (xdev->chan[i])
    > + xilinx_vdma_chan_remove(xdev->chan[i]);
    > + }
    > +
    > + return err;
    > +}
    > +
    > +/**
    > + * xilinx_vdma_remove - Driver remove function
    > + * @pdev: Pointer to the platform_device structure
    > + *
    > + * Return: Always '0'
    > + */
    > +static int xilinx_vdma_remove(struct platform_device *pdev)
    > +{
    > + struct xilinx_vdma_device *xdev;
    > + int i;
    > +
    > + of_dma_controller_free(pdev->dev.of_node);
    > +
    > + xdev = platform_get_drvdata(pdev);
    > + dma_async_device_unregister(&xdev->common);
    > +
    > + for (i = 0; i < XILINX_VDMA_MAX_CHANS_PER_DEVICE; i++) {
    > + if (xdev->chan[i])
    > + xilinx_vdma_chan_remove(xdev->chan[i]);
    > + }
    > +
    > + return 0;
    > +}
    > +
    > +static const struct of_device_id xilinx_vdma_of_ids[] = {
    > + { .compatible = "xlnx,axi-vdma-1.00.a",},
    > + {}
    > +};
    > +
    > +static struct platform_driver xilinx_vdma_driver = {
    > + .driver = {
    > + .name = "xilinx-vdma",
    > + .owner = THIS_MODULE,
    > + .of_match_table = xilinx_vdma_of_ids,
    > + },
    > + .probe = xilinx_vdma_probe,
    > + .remove = xilinx_vdma_remove,
    > +};
    > +
    > +module_platform_driver(xilinx_vdma_driver);
    > +
    > +MODULE_AUTHOR("Xilinx, Inc.");
    > +MODULE_DESCRIPTION("Xilinx VDMA driver");
    > +MODULE_LICENSE("GPL v2");
    > diff --git a/drivers/dma/xilinx/xilinx_vdma_test.c b/drivers/dma/xilinx/xilinx_vdma_test.c
    > new file mode 100644
    > index 0000000..813b67c
    > --- /dev/null
    > +++ b/drivers/dma/xilinx/xilinx_vdma_test.c
    > @@ -0,0 +1,629 @@
    > +/*
    > + * XILINX VDMA Engine test client driver
    > + *
    > + * Copyright (C) 2010-2013 Xilinx, Inc. All rights reserved.
    > + *
    > + * Based on Atmel DMA Test Client
    > + *
    > + * Description:
    > + * This is a simple Xilinx VDMA test client for AXI VDMA driver.
    > + * This test assumes both the channels of VDMA are enabled in the
    > + * hardware design and configured in back-to-back connection. Test
    > + * starts by pumping the data onto one channel (MM2S) and then
    > + * compares the data that is received on the other channel (S2MM).
    > + *
    > + * This program is free software; you can redistribute it and/or modify
    > + * it under the terms of the GNU General Public License version 2 as
    > + * published by the Free Software Foundation.
    > + */
    > +
    > +#include <linux/amba/xilinx_dma.h>
    > +#include <linux/delay.h>
    > +#include <linux/init.h>
    > +#include <linux/kthread.h>
    > +#include <linux/module.h>
    > +#include <linux/of_dma.h>
    > +#include <linux/platform_device.h>
    > +#include <linux/random.h>
    > +#include <linux/slab.h>
    > +#include <linux/wait.h>
    > +
    > +static unsigned int test_buf_size = 64;
    > +module_param(test_buf_size, uint, S_IRUGO);
    > +MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer");
    > +
    > +static unsigned int iterations;
    > +module_param(iterations, uint, S_IRUGO);
    > +MODULE_PARM_DESC(iterations,
    > + "Iterations before stopping test (default: infinite)");
    > +
    > +/*
    > + * Initialization patterns. All bytes in the source buffer has bit 7
    > + * set, all bytes in the destination buffer has bit 7 cleared.
    > + *
    > + * Bit 6 is set for all bytes which are to be copied by the DMA
    > + * engine. Bit 5 is set for all bytes which are to be overwritten by
    > + * the DMA engine.
    > + *
    > + * The remaining bits are the inverse of a counter which increments by
    > + * one for each byte address.
    > + */
    > +#define PATTERN_SRC 0x80
    > +#define PATTERN_DST 0x00
    > +#define PATTERN_COPY 0x40
    > +#define PATTERN_OVERWRITE 0x20
    > +#define PATTERN_COUNT_MASK 0x1f
    > +
    > +/* Maximum number of frame buffers */
    > +#define MAX_NUM_FRAMES 32
    > +
    > +/**
    > + * struct vdmatest_slave_thread - VDMA test thread
    > + * @node: Thread node
    > + * @task: Task structure pointer
    > + * @tx_chan: Tx channel pointer
    > + * @rx_chan: Rx Channel pointer
    > + * @srcs: Source buffer
    > + * @dsts: Destination buffer
    > + * @type: DMA transaction type
    > + */
    > +struct xilinx_vdmatest_slave_thread {
    > + struct list_head node;
    > + struct task_struct *task;
    > + struct dma_chan *tx_chan;
    > + struct dma_chan *rx_chan;
    > + u8 **srcs;
    > + u8 **dsts;
    > + enum dma_transaction_type type;
    > +};
    > +
    > +/**
    > + * struct vdmatest_chan - VDMA Test channel
    > + * @node: Channel node
    > + * @chan: DMA channel pointer
    > + * @threads: List of VDMA test threads
    > + */
    > +struct xilinx_vdmatest_chan {
    > + struct list_head node;
    > + struct dma_chan *chan;
    > + struct list_head threads;
    > +};
    > +
    > +/* Global variables */
    > +static LIST_HEAD(xilinx_vdmatest_channels);
    > +static unsigned int nr_channels;
    > +static unsigned int frm_cnt;
    > +static dma_addr_t dma_srcs[MAX_NUM_FRAMES];
    > +static dma_addr_t dma_dsts[MAX_NUM_FRAMES];
    > +static struct scatterlist tx_sg[MAX_NUM_FRAMES];
    > +static struct scatterlist rx_sg[MAX_NUM_FRAMES];
    > +
    > +static void xilinx_vdmatest_init_srcs(u8 **bufs, unsigned int start,
    > + unsigned int len)
    > +{
    > + unsigned int i;
    > + u8 *buf;
    > +
    > + for (; (buf = *bufs); bufs++) {
    > + for (i = 0; i < start; i++)
    > + buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
    > + for (; i < start + len; i++)
    > + buf[i] = PATTERN_SRC | PATTERN_COPY
    > + | (~i & PATTERN_COUNT_MASK);
    > + for (; i < test_buf_size; i++)
    > + buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
    > + buf++;
    > + }
    > +}
    > +
    > +static void xilinx_vdmatest_init_dsts(u8 **bufs, unsigned int start,
    > + unsigned int len)
    > +{
    > + unsigned int i;
    > + u8 *buf;
    > +
    > + for (; (buf = *bufs); bufs++) {
    > + for (i = 0; i < start; i++)
    > + buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
    > + for (; i < start + len; i++)
    > + buf[i] = PATTERN_DST | PATTERN_OVERWRITE
    > + | (~i & PATTERN_COUNT_MASK);
    > + for (; i < test_buf_size; i++)
    > + buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
    > + }
    > +}
    > +
    > +static void xilinx_vdmatest_mismatch(u8 actual, u8 pattern, unsigned int index,
    > + unsigned int counter, bool is_srcbuf)
    > +{
    > + u8 diff = actual ^ pattern;
    > + u8 expected = pattern | (~counter & PATTERN_COUNT_MASK);
    > + const char *thread_name = current->comm;
    > +
    > + if (is_srcbuf)
    > + pr_warn(
    > + "%s: srcbuf[0x%x] overwritten! Expected %02x, got %02x\n",
    > + thread_name, index, expected, actual);
    > + else if ((pattern & PATTERN_COPY)
    > + && (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
    > + pr_warn(
    > + "%s: dstbuf[0x%x] not copied! Expected %02x, got %02x\n",
    > + thread_name, index, expected, actual);
    > + else if (diff & PATTERN_SRC)
    > + pr_warn(
    > + "%s: dstbuf[0x%x] was copied! Expected %02x, got %02x\n",
    > + thread_name, index, expected, actual);
    > + else
    > + pr_warn(
    > + "%s: dstbuf[0x%x] mismatch! Expected %02x, got %02x\n",
    > + thread_name, index, expected, actual);
    > +}
    > +
    > +static unsigned int xilinx_vdmatest_verify(u8 **bufs, unsigned int start,
    > + unsigned int end, unsigned int counter, u8 pattern,
    > + bool is_srcbuf)
    > +{
    > + unsigned int i, error_count = 0;
    > + u8 actual, expected, *buf;
    > + unsigned int counter_orig = counter;
    > +
    > + for (; (buf = *bufs); bufs++) {
    > + counter = counter_orig;
    > + for (i = start; i < end; i++) {
    > + actual = buf[i];
    > + expected = pattern | (~counter & PATTERN_COUNT_MASK);
    > + if (actual != expected) {
    > + if (error_count < 32)
    > + xilinx_vdmatest_mismatch(actual,
    > + pattern, i,
    > + counter, is_srcbuf);
    > + error_count++;
    > + }
    > + counter++;
    > + }
    > + }
    > +
    > + if (error_count > 32)
    > + pr_warn("%s: %u errors suppressed\n",
    > + current->comm, error_count - 32);
    > +
    > + return error_count;
    > +}
    > +
    > +static void xilinx_vdmatest_slave_tx_callback(void *completion)
    > +{
    > + pr_debug("Got tx callback\n");
    > + complete(completion);
    > +}
    > +
    > +static void xilinx_vdmatest_slave_rx_callback(void *completion)
    > +{
    > + pr_debug("Got rx callback\n");
    > + complete(completion);
    > +}
    > +
    > +/*
    > + * Function for slave transfers
    > + * Each thread requires 2 channels, one for transmit, and one for receive
    > + */
    > +static int xilinx_vdmatest_slave_func(void *data)
    > +{
    > + struct xilinx_vdmatest_slave_thread *thread = data;
    > + struct dma_chan *tx_chan, *rx_chan;
    > + const char *thread_name;
    > + unsigned int len, error_count;
    > + unsigned int failed_tests = 0, total_tests = 0;
    > + dma_cookie_t tx_cookie, rx_cookie;
    > + enum dma_status status;
    > + enum dma_ctrl_flags flags;
    > + int ret = -ENOMEM, i;
    > + int hsize = 64, vsize = 32;
    > + struct xilinx_vdma_config config;
    > +
    > + thread_name = current->comm;
    > +
    > + /* Limit testing scope here */
    > + iterations = 1;
    > + test_buf_size = hsize * vsize;
    > +
    > + /* This barrier ensures 'thread' is initialized and
    > + * we get valid DMA channels
    > + */
    > + smp_rmb();
    > + tx_chan = thread->tx_chan;
    > + rx_chan = thread->rx_chan;
    > +
    > + thread->srcs = kcalloc(frm_cnt+1, sizeof(u8 *), GFP_KERNEL);
    > + if (!thread->srcs)
    > + goto err_srcs;
    > + for (i = 0; i < frm_cnt; i++) {
    > + thread->srcs[i] = kmalloc(test_buf_size, GFP_KERNEL);
    > + if (!thread->srcs[i])
    > + goto err_srcbuf;
    > + }
    > +
    > + thread->dsts = kcalloc(frm_cnt+1, sizeof(u8 *), GFP_KERNEL);
    > + if (!thread->dsts)
    > + goto err_dsts;
    > + for (i = 0; i < frm_cnt; i++) {
    > + thread->dsts[i] = kmalloc(test_buf_size, GFP_KERNEL);
    > + if (!thread->dsts[i])
    > + goto err_dstbuf;
    > + }
    > +
    > + set_user_nice(current, 10);
    > +
    > + flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
    > +
    > + while (!kthread_should_stop()
    > + && !(iterations && total_tests >= iterations)) {
    > + struct dma_device *tx_dev = tx_chan->device;
    > + struct dma_device *rx_dev = rx_chan->device;
    > + struct dma_async_tx_descriptor *txd = NULL;
    > + struct dma_async_tx_descriptor *rxd = NULL;
    > + struct completion rx_cmp, tx_cmp;
    > + unsigned long rx_tmo =
    > + msecs_to_jiffies(30000); /* RX takes longer */
    > + unsigned long tx_tmo = msecs_to_jiffies(30000);
    > + u8 align = 0;
    > +
    > + total_tests++;
    > +
    > + /* honor larger alignment restrictions */
    > + align = tx_dev->copy_align;
    > + if (rx_dev->copy_align > align)
    > + align = rx_dev->copy_align;
    > +
    > + if (1 << align > test_buf_size) {
    > + pr_err("%u-byte buffer too small for %d-byte alignment\n",
    > + test_buf_size, 1 << align);
    > + break;
    > + }
    > +
    > + len = test_buf_size;
    > + xilinx_vdmatest_init_srcs(thread->srcs, 0, len);
    > + xilinx_vdmatest_init_dsts(thread->dsts, 0, len);
    > +
    > + sg_init_table(tx_sg, frm_cnt);
    > + sg_init_table(rx_sg, frm_cnt);
    > +
    > + for (i = 0; i < frm_cnt; i++) {
    > + u8 *buf = thread->srcs[i];
    > +
    > + dma_srcs[i] = dma_map_single(tx_dev->dev, buf, len,
    > + DMA_MEM_TO_DEV);
    > + pr_debug("src buf %x dma %x\n", (unsigned int)buf,
    > + (unsigned int)dma_srcs[i]);
    > + sg_dma_address(&tx_sg[i]) = dma_srcs[i];
    > + sg_dma_len(&tx_sg[i]) = len;
    > + }
    > +
    > + for (i = 0; i < frm_cnt; i++) {
    > + dma_dsts[i] = dma_map_single(rx_dev->dev,
    > + thread->dsts[i],
    > + test_buf_size,
    > + DMA_DEV_TO_MEM);
    > + pr_debug("dst %x dma %x\n",
    > + (unsigned int)thread->dsts[i],
    > + (unsigned int)dma_dsts[i]);
    > + sg_dma_address(&rx_sg[i]) = dma_dsts[i];
    > + sg_dma_len(&rx_sg[i]) = len;
    > + }
    > +
    > + /* Zero out configuration */
    > + memset(&config, 0, sizeof(struct xilinx_vdma_config));
    > +
    > + /* Set up hardware configuration information */
    > + config.vsize = vsize;
    > + config.hsize = hsize;
    > + config.stride = hsize;
    > + config.frm_cnt_en = 1;
    > + config.coalesc = frm_cnt * 10;
    > + config.park = 1;
    > + tx_dev->device_control(tx_chan, DMA_SLAVE_CONFIG,
    > + (unsigned long)&config);
    > +
    > + config.park = 0;
    > + rx_dev->device_control(rx_chan, DMA_SLAVE_CONFIG,
    > + (unsigned long)&config);
    > +
    > + rxd = rx_dev->device_prep_slave_sg(rx_chan, rx_sg, frm_cnt,
    > + DMA_DEV_TO_MEM, flags, NULL);
    > +
    > + txd = tx_dev->device_prep_slave_sg(tx_chan, tx_sg, frm_cnt,
    > + DMA_MEM_TO_DEV, flags, NULL);
    > +
    > + if (!rxd || !txd) {
    > + for (i = 0; i < frm_cnt; i++)
    > + dma_unmap_single(tx_dev->dev, dma_srcs[i], len,
    > + DMA_MEM_TO_DEV);
    > + for (i = 0; i < frm_cnt; i++)
    > + dma_unmap_single(rx_dev->dev, dma_dsts[i],
    > + test_buf_size,
    > + DMA_DEV_TO_MEM);
    > + pr_warn("%s: #%u: prep error with len=0x%x ",
    > + thread_name, total_tests - 1, len);
    > + msleep(100);
    > + failed_tests++;
    > + continue;
    > + }
    > +
    > + init_completion(&rx_cmp);
    > + rxd->callback = xilinx_vdmatest_slave_rx_callback;
    > + rxd->callback_param = &rx_cmp;
    > + rx_cookie = rxd->tx_submit(rxd);
    > +
    > + init_completion(&tx_cmp);
    > + txd->callback = xilinx_vdmatest_slave_tx_callback;
    > + txd->callback_param = &tx_cmp;
    > + tx_cookie = txd->tx_submit(txd);
    > +
    > + if (dma_submit_error(rx_cookie) ||
    > + dma_submit_error(tx_cookie)) {
    > + pr_warn("%s: #%u: submit error %d/%d with len=0x%x ",
    > + thread_name, total_tests - 1,
    > + rx_cookie, tx_cookie, len);
    > + msleep(100);
    > + failed_tests++;
    > + continue;
    > + }
    > + dma_async_issue_pending(tx_chan);
    > + dma_async_issue_pending(rx_chan);
    > +
    > + tx_tmo = wait_for_completion_timeout(&tx_cmp, tx_tmo);
    > +
    > + status = dma_async_is_tx_complete(tx_chan, tx_cookie,
    > + NULL, NULL);
    > +
    > + if (tx_tmo == 0) {
    > + pr_warn("%s: #%u: tx test timed out\n",
    > + thread_name, total_tests - 1);
    > + failed_tests++;
    > + continue;
    > + } else if (status != DMA_COMPLETE) {
    > + pr_warn(
    > + "%s: #%u: tx got completion callback, ",
    > + thread_name, total_tests - 1);
    > + pr_warn("but status is \'%s\'\n",
    > + status == DMA_ERROR ? "error" :
    > + "in progress");
    > + failed_tests++;
    > + continue;
    > + }
    > +
    > + rx_tmo = wait_for_completion_timeout(&rx_cmp, rx_tmo);
    > + status = dma_async_is_tx_complete(rx_chan, rx_cookie,
    > + NULL, NULL);
    > +
    > + if (rx_tmo == 0) {
    > + pr_warn("%s: #%u: rx test timed out\n",
    > + thread_name, total_tests - 1);
    > + failed_tests++;
    > + continue;
    > + } else if (status != DMA_COMPLETE) {
    > + pr_warn(
    > + "%s: #%u: rx got completion callback, ",
    > + thread_name, total_tests - 1);
    > + pr_warn("but status is \'%s\'\n",
    > + status == DMA_ERROR ? "error" :
    > + "in progress");
    > + failed_tests++;
    > + continue;
    > + }
    > +
    > + for (i = 0; i < frm_cnt; i++)
    > + dma_unmap_single(rx_dev->dev, dma_dsts[i],
    > + test_buf_size, DMA_DEV_TO_MEM);
    > +
    > + error_count = 0;
    > +
    > + pr_debug("%s: verifying source buffer...\n", thread_name);
    > + error_count += xilinx_vdmatest_verify(thread->srcs, 0, 0,
    > + 0, PATTERN_SRC, true);
    > + error_count += xilinx_vdmatest_verify(thread->srcs, 0,
    > + len, 0, PATTERN_SRC | PATTERN_COPY, true);
    > + error_count += xilinx_vdmatest_verify(thread->srcs, len,
    > + test_buf_size, len, PATTERN_SRC, true);
    > +
    > + pr_debug("%s: verifying dest buffer...\n",
    > + thread->task->comm);
    > + error_count += xilinx_vdmatest_verify(thread->dsts, 0, 0,
    > + 0, PATTERN_DST, false);
    > + error_count += xilinx_vdmatest_verify(thread->dsts, 0,
    > + len, 0, PATTERN_SRC | PATTERN_COPY, false);
    > + error_count += xilinx_vdmatest_verify(thread->dsts, len,
    > + test_buf_size, len, PATTERN_DST, false);
    > +
    > + if (error_count) {
    > + pr_warn("%s: #%u: %u errors with len=0x%x\n",
    > + thread_name, total_tests - 1, error_count, len);
    > + failed_tests++;
    > + } else {
    > + pr_debug("%s: #%u: No errors with len=0x%x\n",
    > + thread_name, total_tests - 1, len);
    > + }
    > + }
    > +
    > + ret = 0;
    > + for (i = 0; thread->dsts[i]; i++)
    > + kfree(thread->dsts[i]);
    > +err_dstbuf:
    > + kfree(thread->dsts);
    > +err_dsts:
    > + for (i = 0; thread->srcs[i]; i++)
    > + kfree(thread->srcs[i]);
    > +err_srcbuf:
    > + kfree(thread->srcs);
    > +err_srcs:
    > + pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
    > + thread_name, total_tests, failed_tests, ret);
    > +
    > + if (iterations > 0)
    > + while (!kthread_should_stop()) {
    > + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wait_vdmatest_exit);
    > + interruptible_sleep_on(&wait_vdmatest_exit);
    > + }
    > +
    > + return ret;
    > +}
    > +
    > +static void xilinx_vdmatest_cleanup_channel(struct xilinx_vdmatest_chan *dtc)
    > +{
    > + struct xilinx_vdmatest_slave_thread *thread, *_thread;
    > + int ret;
    > +
    > + list_for_each_entry_safe(thread, _thread,
    > + &dtc->threads, node) {
    > + ret = kthread_stop(thread->task);
    > + pr_info("xilinx_vdmatest: thread %s exited with status %d\n",
    > + thread->task->comm, ret);
    > + list_del(&thread->node);
    > + kfree(thread);
    > + }
    > + kfree(dtc);
    > +}
    > +
    > +static int
    > +xilinx_vdmatest_add_slave_threads(struct xilinx_vdmatest_chan *tx_dtc,
    > + struct xilinx_vdmatest_chan *rx_dtc)
    > +{
    > + struct xilinx_vdmatest_slave_thread *thread;
    > + struct dma_chan *tx_chan = tx_dtc->chan;
    > + struct dma_chan *rx_chan = rx_dtc->chan;
    > +
    > + thread = kzalloc(sizeof(struct xilinx_vdmatest_slave_thread),
    > + GFP_KERNEL);
    > + if (!thread)
    > + pr_warn("xilinx_vdmatest: No memory for slave thread %s-%s\n",
    > + dma_chan_name(tx_chan), dma_chan_name(rx_chan));
    > +
    > + thread->tx_chan = tx_chan;
    > + thread->rx_chan = rx_chan;
    > + thread->type = (enum dma_transaction_type)DMA_SLAVE;
    > +
    > + /* This barrier ensures the DMA channels in the 'thread'
    > + * are initialized
    > + */
    > + smp_wmb();
    > + thread->task = kthread_run(xilinx_vdmatest_slave_func, thread, "%s-%s",
    > + dma_chan_name(tx_chan), dma_chan_name(rx_chan));
    > + if (IS_ERR(thread->task)) {
    > + pr_warn("xilinx_vdmatest: Failed to run thread %s-%s\n",
    > + dma_chan_name(tx_chan), dma_chan_name(rx_chan));
    > + kfree(thread);
    > + }
    > +
    > + list_add_tail(&thread->node, &tx_dtc->threads);
    > +
    > + /* Added one thread with 2 channels */
    > + return 1;
    > +}
    > +
    > +static int xilinx_vdmatest_add_slave_channels(struct dma_chan *tx_chan,
    > + struct dma_chan *rx_chan)
    > +{
    > + struct xilinx_vdmatest_chan *tx_dtc, *rx_dtc;
    > + unsigned int thread_count = 0;
    > +
    > + tx_dtc = kmalloc(sizeof(struct xilinx_vdmatest_chan), GFP_KERNEL);
    > + if (!tx_dtc)
    > + return -ENOMEM;
    > +
    > + rx_dtc = kmalloc(sizeof(struct xilinx_vdmatest_chan), GFP_KERNEL);
    > + if (!rx_dtc)
    > + return -ENOMEM;
    > +
    > + tx_dtc->chan = tx_chan;
    > + rx_dtc->chan = rx_chan;
    > + INIT_LIST_HEAD(&tx_dtc->threads);
    > + INIT_LIST_HEAD(&rx_dtc->threads);
    > +
    > + xilinx_vdmatest_add_slave_threads(tx_dtc, rx_dtc);
    > + thread_count += 1;
    > +
    > + pr_info("xilinx_vdmatest: Started %u threads using %s %s\n",
    > + thread_count, dma_chan_name(tx_chan), dma_chan_name(rx_chan));
    > +
    > + list_add_tail(&tx_dtc->node, &xilinx_vdmatest_channels);
    > + list_add_tail(&rx_dtc->node, &xilinx_vdmatest_channels);
    > + nr_channels += 2;
    > +
    > + return 0;
    > +}
    > +
    > +static int xilinx_vdmatest_probe(struct platform_device *pdev)
    > +{
    > + struct dma_chan *chan, *rx_chan;
    > + int err;
    > +
    > + err = of_property_read_u32(pdev->dev.of_node,
    > + "xlnx,num-fstores", &frm_cnt);
    > + if (err < 0) {
    > + pr_err("xilinx_vdmatest: missing xlnx,num-fstores property\n");
    > + return err;
    > + }
    > +
    > + chan = dma_request_slave_channel(&pdev->dev, "vdma0");
    > + if (IS_ERR(chan)) {
    > + pr_err("xilinx_vdmatest: No Tx channel\n");
    > + return PTR_ERR(chan);
    > + }
    > +
    > + rx_chan = dma_request_slave_channel(&pdev->dev, "vdma1");
    > + if (IS_ERR(rx_chan)) {
    > + err = PTR_ERR(rx_chan);
    > + pr_err("xilinx_vdmatest: No Rx channel\n");
    > + goto free_tx;
    > + }
    > +
    > + err = xilinx_vdmatest_add_slave_channels(chan, rx_chan);
    > + if (err) {
    > + pr_err("xilinx_vdmatest: Unable to add channels\n");
    > + goto free_rx;
    > + }
    > + return 0;
    > +
    > +free_rx:
    > + dma_release_channel(rx_chan);
    > +free_tx:
    > + dma_release_channel(chan);
    > +
    > + return err;
    > +}
    > +
    > +static int xilinx_vdmatest_remove(struct platform_device *pdev)
    > +{
    > + struct xilinx_vdmatest_chan *dtc, *_dtc;
    > + struct dma_chan *chan;
    > +
    > + list_for_each_entry_safe(dtc, _dtc, &xilinx_vdmatest_channels, node) {
    > + list_del(&dtc->node);
    > + chan = dtc->chan;
    > + xilinx_vdmatest_cleanup_channel(dtc);
    > + pr_info("xilinx_vdmatest: dropped channel %s\n",
    > + dma_chan_name(chan));
    > + dma_release_channel(chan);
    > + }
    > + return 0;
    > +}
    > +
    > +static const struct of_device_id xilinx_vdmatest_of_ids[] = {
    > + { .compatible = "xlnx,axi-vdma-test-1.00.a",},
    > + {}
    > +};
    > +
    > +static struct platform_driver xilinx_vdmatest_driver = {
    > + .driver = {
    > + .name = "xilinx_vdmatest",
    > + .owner = THIS_MODULE,
    > + .of_match_table = xilinx_vdmatest_of_ids,
    > + },
    > + .probe = xilinx_vdmatest_probe,
    > + .remove = xilinx_vdmatest_remove,
    > +};
    > +
    > +module_platform_driver(xilinx_vdmatest_driver);
    > +
    > +MODULE_AUTHOR("Xilinx, Inc.");
    > +MODULE_DESCRIPTION("Xilinx AXI VDMA Test Client");
    > +MODULE_LICENSE("GPL v2");
    >



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