[PATCH v2] dmaengine: dw-edma: fix MSI data programming for multi-IRQ case

[Shenghui Shi <ssh.mediatek@gmail.com>]

When using MSI (not MSI-X) with multiple IRQs, the MSI data value
must be unique per vector to ensure correct interrupt delivery.
Currently, the driver fails to increment the MSI data per vector,
causing interrupts to be misrouted.

Fix this by caching the base MSI data and adjusting each vector's
data accordingly during IRQ setup.

This issue was reproduced and tested on:
- Device: [20e0:2502] (rev 01)
- Kernel: 6.8.0-90-generic

Fixes: e63d79d1ff04 ("dmaengine: dw-edma: Add Synopsys DesignWare eDMA IP core driver")

Signed-off-by: Shenghui Shi <brody.shi@m2semi.com>
---
 drivers/dma/dw-edma/dw-edma-core.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 8e5f7defa..516770388 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -844,11 +844,15 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 {
 	struct dw_edma_chip *chip = dw->chip;
 	struct device *dev = dw->chip->dev;
+	struct msi_desc *msi_desc;
 	u32 wr_mask = 1;
 	u32 rd_mask = 1;
 	int i, err = 0;
 	u32 ch_cnt;
 	int irq;
+	u16 msi_base_data = 0;
+	bool msi_base_valid = false;
+	bool is_msix = false;
 
 	ch_cnt = dw->wr_ch_cnt + dw->rd_ch_cnt;
 
@@ -869,8 +873,15 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 			return err;
 		}
 
-		if (irq_get_msi_desc(irq))
+		if (irq_get_msi_desc(irq)) {
 			get_cached_msi_msg(irq, &dw->irq[0].msi);
+			msi_desc = irq_get_msi_desc(irq);
+			is_msix = msi_desc && msi_desc->pci.msi_attrib.is_msix;
+			if (!is_msix) {
+				msi_base_data = dw->irq[0].msi.data;
+				msi_base_valid = true;
+			}
+		}
 
 		dw->nr_irqs = 1;
 	} else {
@@ -896,8 +907,18 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 			if (err)
 				goto err_irq_free;
 
-			if (irq_get_msi_desc(irq))
+			if (irq_get_msi_desc(irq)) {
 				get_cached_msi_msg(irq, &dw->irq[i].msi);
+				msi_desc = irq_get_msi_desc(irq);
+				is_msix = msi_desc && msi_desc->pci.msi_attrib.is_msix;
+				if (!is_msix) {
+					if (!msi_base_valid) {
+						msi_base_data = dw->irq[i].msi.data;
+						msi_base_valid = true;
+					}
+					dw->irq[i].msi.data = (u16)(msi_base_data + i);
+				}
+			}
 		}
 
 		dw->nr_irqs = i;
-- 
2.49.0.windows.1