fsldma: fix infinite loop on multi-descriptor DMA chain completion
When creating a DMA transaction with multiple descriptors, the async_tx cookie is set to 0 for each descriptor in the chain, excluding the last descriptor, whose cookie is set to -EBUSY. When fsl_dma_tx_submit() is run, it only assigns a cookie to the first descriptor. All of the remaining descriptors keep their original value, including the last descriptor, which is set to -EBUSY. After the DMA completes, the driver will update the last completed cookie to be -EBUSY, which is an error code instead of a valid cookie. This causes dma_async_is_complete() to always return DMA_IN_PROGRESS. This causes the fsldma driver to never cleanup the queue of link descriptors, and the driver will re-run the DMA transaction on the hardware each time it receives the End-of-Chain interrupt. This causes an infinite loop. With this patch, fsl_dma_tx_submit() is changed to assign a cookie to every descriptor in the chain. The rest of the code then works without problems. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Li Yang <leoli@freescale.com>
This commit is contained in:
parent
138ef01851
commit
bcfb7465c0
1 changed files with 11 additions and 8 deletions
|
@ -313,8 +313,8 @@ static void fsl_chan_toggle_ext_start(struct fsl_dma_chan *fsl_chan, int enable)
|
|||
|
||||
static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
|
||||
{
|
||||
struct fsl_desc_sw *desc = tx_to_fsl_desc(tx);
|
||||
struct fsl_dma_chan *fsl_chan = to_fsl_chan(tx->chan);
|
||||
struct fsl_desc_sw *desc;
|
||||
unsigned long flags;
|
||||
dma_cookie_t cookie;
|
||||
|
||||
|
@ -322,14 +322,17 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
|
|||
spin_lock_irqsave(&fsl_chan->desc_lock, flags);
|
||||
|
||||
cookie = fsl_chan->common.cookie;
|
||||
cookie++;
|
||||
if (cookie < 0)
|
||||
cookie = 1;
|
||||
desc->async_tx.cookie = cookie;
|
||||
fsl_chan->common.cookie = desc->async_tx.cookie;
|
||||
list_for_each_entry(desc, &tx->tx_list, node) {
|
||||
cookie++;
|
||||
if (cookie < 0)
|
||||
cookie = 1;
|
||||
|
||||
append_ld_queue(fsl_chan, desc);
|
||||
list_splice_init(&desc->async_tx.tx_list, fsl_chan->ld_queue.prev);
|
||||
desc->async_tx.cookie = cookie;
|
||||
}
|
||||
|
||||
fsl_chan->common.cookie = cookie;
|
||||
append_ld_queue(fsl_chan, tx_to_fsl_desc(tx));
|
||||
list_splice_init(&tx->tx_list, fsl_chan->ld_queue.prev);
|
||||
|
||||
spin_unlock_irqrestore(&fsl_chan->desc_lock, flags);
|
||||
|
||||
|
|
Reference in a new issue