[PATCH v2 2/5] dma: mcf-edma: Add per-channel IRQ naming for debugging

Jean-Michel Hautbois via B4 Relay
2025-11-26T08:36:04Z

From: Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>

Add dynamic per-channel IRQ naming to make DMA interrupt identification
easier in /proc/interrupts and debugging tools.

Instead of all channels showing "eDMA", they now show:
- "eDMA-0" through "eDMA-15" for channels 0-15
- "eDMA-16" through "eDMA-55" for channels 16-55
- "eDMA-tx-56" for the shared channel 56-63 interrupt
- "eDMA-err" for the error interrupt

This aids debugging DMA issues by making it clear which channel's
interrupt is being serviced.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>
---
drivers/dma/mcf-edma-main.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/mcf-edma-main.c b/drivers/dma/mcf-edma-main.c
index f95114829d80..6a7d88895501 100644
--- a/drivers/dma/mcf-edma-main.c
+++ b/drivers/dma/mcf-edma-main.c
@@ -81,8 +81,14 @@ static int mcf_edma_irq_init(struct platform_device *pdev,
if (!res)
return -1;

- for (ret = 0, i = res->start; i <= res->end; ++i)
- ret |= request_irq(i, mcf_edma_tx_handler, 0, "eDMA", mcf_edma);
+ for (ret = 0, i = res->start; i <= res->end; ++i) {
+ char *irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+ "eDMA-%d", (int)(i - res->start));
+ if (!irq_name)
+ return -ENOMEM;
+
+ ret |= request_irq(i, mcf_edma_tx_handler, 0, irq_name, mcf_edma);
+ }
if (ret)
return ret;

@@ -91,23 +97,27 @@ static int mcf_edma_irq_init(struct platform_device *pdev,
if (!res)
return -1;

- for (ret = 0, i = res->start; i <= res->end; ++i)
- ret |= request_irq(i, mcf_edma_tx_handler, 0, "eDMA", mcf_edma);
+ for (ret = 0, i = res->start; i <= res->end; ++i) {
+ char *irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+ "eDMA-%d", (int)(16 + i - res->start));
+ if (!irq_name)
+ return -ENOMEM;
+
+ ret |= request_irq(i, mcf_edma_tx_handler, 0, irq_name, mcf_edma);
+ }
if (ret)
return ret;

ret = platform_get_irq_byname(pdev, "edma-tx-56-63");
if (ret != -ENXIO) {
- ret = request_irq(ret, mcf_edma_tx_handler,
- 0, "eDMA", mcf_edma);
+ ret = request_irq(ret, mcf_edma_tx_handler, 0, "eDMA-tx-56", mcf_edma);
if (ret)
return ret;
}

ret = platform_get_irq_byname(pdev, "edma-err");
if (ret != -ENXIO) {
- ret = request_irq(ret, mcf_edma_err_handler,
- 0, "eDMA", mcf_edma);
+ ret = request_irq(ret, mcf_edma_err_handler, 0, "eDMA-err", mcf_edma);
if (ret)
return ret;
}

--
2.39.5