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    Subject[PATCH 4.4 246/342] dmaengine: dw: fix cyclic transfer setup
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Mans Rullgard <mans@mansr.com>

    commit df3bb8a0e619d501cd13334c3e0586edcdcbc716 upstream.

    Commit 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and
    chan_cfg register on resume") moved some channel initialisation to
    a new function which must be called before starting a transfer.

    This updates dw_dma_cyclic_start() to use dwc_dostart() like the other
    modes, thus ensuring dwc_initialize() gets called and removing some code
    duplication.

    Fixes: 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and chan_cfg register on resume")
    Signed-off-by: Mans Rullgard <mans@mansr.com>
    Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
    Signed-off-by: Vinod Koul <vinod.koul@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/dma/dw/core.c | 23 +----------------------
    1 file changed, 1 insertion(+), 22 deletions(-)

    --- a/drivers/dma/dw/core.c
    +++ b/drivers/dma/dw/core.c
    @@ -1245,7 +1245,6 @@ static void dwc_free_chan_resources(stru
    int dw_dma_cyclic_start(struct dma_chan *chan)
    {
    struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
    - struct dw_dma *dw = to_dw_dma(dwc->chan.device);
    unsigned long flags;

    if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) {
    @@ -1254,27 +1253,7 @@ int dw_dma_cyclic_start(struct dma_chan
    }

    spin_lock_irqsave(&dwc->lock, flags);
    -
    - /* Assert channel is idle */
    - if (dma_readl(dw, CH_EN) & dwc->mask) {
    - dev_err(chan2dev(&dwc->chan),
    - "%s: BUG: Attempted to start non-idle channel\n",
    - __func__);
    - dwc_dump_chan_regs(dwc);
    - spin_unlock_irqrestore(&dwc->lock, flags);
    - return -EBUSY;
    - }
    -
    - dma_writel(dw, CLEAR.ERROR, dwc->mask);
    - dma_writel(dw, CLEAR.XFER, dwc->mask);
    -
    - /* Setup DMAC channel registers */
    - channel_writel(dwc, LLP, dwc->cdesc->desc[0]->txd.phys);
    - channel_writel(dwc, CTL_LO, DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
    - channel_writel(dwc, CTL_HI, 0);
    -
    - channel_set_bit(dw, CH_EN, dwc->mask);
    -
    + dwc_dostart(dwc, dwc->cdesc->desc[0]);
    spin_unlock_irqrestore(&dwc->lock, flags);

    return 0;
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