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    SubjectRe: [PATCH v2 1/5] dmaengine: add ep93xx DMA support
    On Mon, Nov 21, 2011 at 08:44:07AM +0100, Rafal Prylowski wrote:
    >
    > I'm calling dma_terminate_all from interrupt. It seems that tasklet_kill is not
    > allowed to be called from this context.

    Ah, right.

    One more try - this time we set a flag which prevents the tasktlet from
    referencing an empty list.

    diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c
    index 6181811..f7244b3 100644
    --- a/drivers/dma/ep93xx_dma.c
    +++ b/drivers/dma/ep93xx_dma.c
    @@ -155,6 +155,8 @@ struct ep93xx_dma_chan {
    unsigned long flags;
    /* Channel is configured for cyclic transfers */
    #define EP93XX_DMA_IS_CYCLIC 0
    +/* Channel is enabled */
    +#define EP93xx_DMA_IS_RUNNING 1

    int buffer;
    dma_cookie_t last_completed;
    @@ -673,6 +675,9 @@ static void ep93xx_dma_tasklet(unsigned long data)
    void *callback_param;
    LIST_HEAD(list);

    + if (!test_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags))
    + return;
    +
    spin_lock_irq(&edmac->lock);
    desc = ep93xx_dma_get_active(edmac);
    if (desc->complete) {
    @@ -758,6 +763,8 @@ static dma_cookie_t ep93xx_dma_tx_submit(struct dma_async_tx_descriptor *tx)
    edmac->chan.cookie = cookie;
    desc->txd.cookie = cookie;

    + set_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags);
    +
    /*
    * If nothing is currently prosessed, we push this descriptor
    * directly to the hardware. Otherwise we put the descriptor
    @@ -1106,6 +1113,7 @@ static int ep93xx_dma_terminate_all(struct ep93xx_dma_chan *edmac)
    spin_lock_irqsave(&edmac->lock, flags);
    /* First we disable and flush the DMA channel */
    edmac->edma->hw_shutdown(edmac);
    + clear_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags);
    clear_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags);
    list_splice_init(&edmac->active, &list);
    list_splice_init(&edmac->queue, &list);

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      Last update: 2011-11-21 09:05    [W:0.027 / U:60.496 seconds]
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