diff options
| -rw-r--r-- | drivers/dma/imx-sdma.c | 36 |
1 files changed, 16 insertions, 20 deletions
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index 03ec76f..aa35a77 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -648,12 +648,6 @@ static void sdma_event_disable(struct sdma_channel *sdmac, unsigned int event) writel_relaxed(val, sdma->regs + chnenbl); } -static void sdma_handle_channel_loop(struct sdma_channel *sdmac) -{ - if (sdmac->desc.callback) - sdmac->desc.callback(sdmac->desc.callback_param); -} - static void sdma_update_channel_loop(struct sdma_channel *sdmac) { struct sdma_buffer_descriptor *bd; @@ -672,13 +666,25 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) sdmac->status = DMA_ERROR; bd->mode.status |= BD_DONE; + + /* + * The callback is called from the interrupt context in order + * to reduce latency and to avoid the risk of altering the + * SDMA transaction status by the time the client tasklet is + * executed. + */ + + if (sdmac->desc.callback) + sdmac->desc.callback(sdmac->desc.callback_param); + sdmac->buf_tail++; sdmac->buf_tail %= sdmac->num_bd; } } -static void mxc_sdma_handle_channel_normal(struct sdma_channel *sdmac) +static void mxc_sdma_handle_channel_normal(unsigned long data) { + struct sdma_channel *sdmac = (struct sdma_channel *) data; struct sdma_buffer_descriptor *bd; int i, error = 0; @@ -705,16 +711,6 @@ static void mxc_sdma_handle_channel_normal(struct sdma_channel *sdmac) sdmac->desc.callback(sdmac->desc.callback_param); } -static void sdma_tasklet(unsigned long data) -{ - struct sdma_channel *sdmac = (struct sdma_channel *) data; - - if (sdmac->flags & IMX_DMA_SG_LOOP) - sdma_handle_channel_loop(sdmac); - else - mxc_sdma_handle_channel_normal(sdmac); -} - static irqreturn_t sdma_int_handler(int irq, void *dev_id) { struct sdma_engine *sdma = dev_id; @@ -731,8 +727,8 @@ static irqreturn_t sdma_int_handler(int irq, void *dev_id) if (sdmac->flags & IMX_DMA_SG_LOOP) sdma_update_channel_loop(sdmac); - - tasklet_schedule(&sdmac->tasklet); + else + tasklet_schedule(&sdmac->tasklet); __clear_bit(channel, &stat); } @@ -1732,7 +1728,7 @@ static int sdma_probe(struct platform_device *pdev) dma_cookie_init(&sdmac->chan); sdmac->channel = i; - tasklet_init(&sdmac->tasklet, sdma_tasklet, + tasklet_init(&sdmac->tasklet, mxc_sdma_handle_channel_normal, (unsigned long) sdmac); /* * Add the channel to the DMAC list. Do not add channel 0 though |