[PATCH v3 3/5] dmaengine: mcf-edma: Fix interrupt handler for 64 DMA channels

[Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>]

Fix the DMA completion interrupt handler to properly handle all 64
channels on MCF54418 ColdFire processors.

The previous code used BIT(ch) to test interrupt status bits, which
causes undefined behavior on 32-bit architectures when ch >= 32 because
unsigned long is 32 bits and the shift would exceed the type width.

Replace with bitmap_from_u64() and for_each_set_bit() which correctly
handle 64-bit values on 32-bit systems by using a proper bitmap
representation.

Fixes: e7a3ff92eaf1 ("dmaengine: fsl-edma: add ColdFire mcf5441x edma support")
Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>
---
 drivers/dma/mcf-edma-main.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/mcf-edma-main.c b/drivers/dma/mcf-edma-main.c
index f95114829d80..953b20f99f25 100644
--- a/drivers/dma/mcf-edma-main.c
+++ b/drivers/dma/mcf-edma-main.c
@@ -18,7 +18,8 @@ static irqreturn_t mcf_edma_tx_handler(int irq, void *dev_id)
 {
 	struct fsl_edma_engine *mcf_edma = dev_id;
 	struct edma_regs *regs = &mcf_edma->regs;
-	unsigned int ch;
+	unsigned long ch;
+	DECLARE_BITMAP(status_mask, 64);
 	u64 intmap;
 
 	intmap = ioread32(regs->inth);
@@ -27,11 +28,11 @@ static irqreturn_t mcf_edma_tx_handler(int irq, void *dev_id)
 	if (!intmap)
 		return IRQ_NONE;
 
-	for (ch = 0; ch < mcf_edma->n_chans; ch++) {
-		if (intmap & BIT(ch)) {
-			iowrite8(EDMA_MASK_CH(ch), regs->cint);
-			fsl_edma_tx_chan_handler(&mcf_edma->chans[ch]);
-		}
+	bitmap_from_u64(status_mask, intmap);
+
+	for_each_set_bit(ch, status_mask, mcf_edma->n_chans) {
+		iowrite8(EDMA_MASK_CH(ch), regs->cint);
+		fsl_edma_tx_chan_handler(&mcf_edma->chans[ch]);
 	}
 
 	return IRQ_HANDLED;

-- 
2.39.5