[PATCH v2 08/64] dmaengine: imx-dma: flip per-chan tasklet to dma_chan BH

From: Allen Pais

Date: Mon Jul 27 2026 - 16:34:53 EST


Replace the per-channel tasklet with the shared dma_chan BH helper.
The handler continues to run in softirq context while dmaengine owns
the common scheduling and teardown mechanism.

Signed-off-by: Allen Pais <allen.lkml@xxxxxxxxx>
---
drivers/dma/imx-dma.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index 81c6276436f8..3ff0bfbfa5ff 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -145,7 +145,6 @@ struct imxdma_channel {
struct imxdma_engine *imxdma;
unsigned int channel;

- struct tasklet_struct dma_tasklet;
struct list_head ld_free;
struct list_head ld_queue;
struct list_head ld_active;
@@ -344,8 +343,8 @@ static void imxdma_watchdog(struct timer_list *t)

imx_dmav1_writel(imxdma, 0, DMA_CCR(channel));

- /* Tasklet watchdog error handler */
- tasklet_schedule(&imxdmac->dma_tasklet);
+ /* BH watchdog error handler */
+ dma_chan_schedule_bh(&imxdmac->chan);
dev_dbg(imxdma->dev, "channel %d: watchdog timeout!\n",
imxdmac->channel);
}
@@ -390,8 +389,8 @@ static irqreturn_t imxdma_err_handler(int irq, void *dev_id)
imx_dmav1_writel(imxdma, 1 << i, DMA_DBOSR);
errcode |= IMX_DMA_ERR_BUFFER;
}
- /* Tasklet error handler */
- tasklet_schedule(&imxdma->channel[i].dma_tasklet);
+ /* BH error handler */
+ dma_chan_schedule_bh(&imxdma->channel[i].chan);

dev_warn(imxdma->dev,
"DMA timeout on channel %d -%s%s%s%s\n", i,
@@ -448,8 +447,8 @@ static void dma_irq_handle_channel(struct imxdma_channel *imxdmac)
imx_dmav1_writel(imxdma, tmp, DMA_CCR(chno));

if (imxdma_chan_is_doing_cyclic(imxdmac))
- /* Tasklet progression */
- tasklet_schedule(&imxdmac->dma_tasklet);
+ /* BH progression */
+ dma_chan_schedule_bh(&imxdmac->chan);

return;
}
@@ -462,8 +461,8 @@ static void dma_irq_handle_channel(struct imxdma_channel *imxdmac)

out:
imx_dmav1_writel(imxdma, 0, DMA_CCR(chno));
- /* Tasklet irq */
- tasklet_schedule(&imxdmac->dma_tasklet);
+ /* Schedule the IRQ BH */
+ dma_chan_schedule_bh(&imxdmac->chan);
}

static irqreturn_t dma_irq_handler(int irq, void *dev_id)
@@ -592,9 +591,10 @@ static int imxdma_xfer_desc(struct imxdma_desc *d)
return 0;
}

-static void imxdma_tasklet(struct tasklet_struct *t)
+static void imxdma_tasklet(struct dma_chan *chan)
{
- struct imxdma_channel *imxdmac = from_tasklet(imxdmac, t, dma_tasklet);
+ struct imxdma_channel *imxdmac = container_of(chan, struct imxdma_channel,
+ chan);
struct imxdma_engine *imxdma = imxdmac->imxdma;
struct imxdma_desc *desc, *next_desc;
unsigned long flags;
@@ -1142,7 +1142,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&imxdmac->ld_free);
INIT_LIST_HEAD(&imxdmac->ld_active);

- tasklet_setup(&imxdmac->dma_tasklet, imxdma_tasklet);
+ dma_chan_init_bh(&imxdmac->chan, imxdma_tasklet);
imxdmac->chan.device = &imxdma->dma_device;
dma_cookie_init(&imxdmac->chan);
imxdmac->channel = i;
@@ -1211,7 +1211,7 @@ static void imxdma_free_irq(struct platform_device *pdev, struct imxdma_engine *
if (!is_imx1_dma(imxdma))
disable_irq(imxdmac->irq);

- tasklet_kill(&imxdmac->dma_tasklet);
+ dma_chan_kill_bh(&imxdmac->chan);
}
}

--
2.43.0