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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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