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dma: tegra: fix residual calculation for cyclic case 

In cyclic mode of DMA, the byte transferred can be more
than the requested size and in this case, calculating
residuals based on the current position of DMA transfer to
bytes requested i.e. bytes required to transfer to reach
bytes requested from current DMA position.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
This commit is contained in:
Laxman Dewangan 2012-07-02 13:52:07 +05:30 committed by Vinod Koul
parent 46fb3f8ef5
commit 4a46ba36e2
1 changed files with 9 additions and 6 deletions
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15
drivers/dma/tegra20-apb-dma.c
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@ -731,6 +731,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
struct tegra_dma_sg_req *sg_req;
enum dma_status ret;
unsigned long flags;
unsigned int residual;
spin_lock_irqsave(&tdc->lock, flags);
@ -744,9 +745,10 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
/* Check on wait_ack desc status */
list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
if (dma_desc->txd.cookie == cookie) {
dma_set_residue(txstate,
dma_desc->bytes_requested -
dma_desc->bytes_transferred);
residual = dma_desc->bytes_requested -
(dma_desc->bytes_transferred %
dma_desc->bytes_requested);
dma_set_residue(txstate, residual);
ret = dma_desc->dma_status;
spin_unlock_irqrestore(&tdc->lock, flags);
return ret;
@ -757,9 +759,10 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
list_for_each_entry(sg_req, &tdc->pending_sg_req, node) {
dma_desc = sg_req->dma_desc;
if (dma_desc->txd.cookie == cookie) {
dma_set_residue(txstate,
dma_desc->bytes_requested -
dma_desc->bytes_transferred);
residual = dma_desc->bytes_requested -
(dma_desc->bytes_transferred %
dma_desc->bytes_requested);
dma_set_residue(txstate, residual);
ret = dma_desc->dma_status;
spin_unlock_irqrestore(&tdc->lock, flags);
return ret;