macb_dma_desc_get_size() does a switch on bp->hw_dma_cap and covers all
four cases: 0, 64B, PTP, 64B+PTP. It also covers the #ifndef
MACB_EXT_DESC separately, making it four codepaths.

Instead, notice the descriptor size grows with enabled features and use
plain if-statements on 64B and PTP flags.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 29 ++++++++---------------------
 1 file changed, 8 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 52270b20d9a1818c961525ae6de6f7d0557ddc54..dfa6b6d2cfedc8d240f55a04f2ada9fa28c55309 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -120,29 +120,16 @@ struct sifive_fu540_macb_mgmt {
  */
 static unsigned int macb_dma_desc_get_size(struct macb *bp)
 {
-#ifdef MACB_EXT_DESC
-	unsigned int desc_size;
+	unsigned int desc_size = sizeof(struct macb_dma_desc);
 
-	switch (bp->hw_dma_cap) {
-	case HW_DMA_CAP_64B:
-		desc_size = sizeof(struct macb_dma_desc)
-			+ sizeof(struct macb_dma_desc_64);
-		break;
-	case HW_DMA_CAP_PTP:
-		desc_size = sizeof(struct macb_dma_desc)
-			+ sizeof(struct macb_dma_desc_ptp);
-		break;
-	case HW_DMA_CAP_64B_PTP:
-		desc_size = sizeof(struct macb_dma_desc)
-			+ sizeof(struct macb_dma_desc_64)
-			+ sizeof(struct macb_dma_desc_ptp);
-		break;
-	default:
-		desc_size = sizeof(struct macb_dma_desc);
-	}
-	return desc_size;
+#ifdef MACB_EXT_DESC
+	if (bp->hw_dma_cap & HW_DMA_CAP_64B)
+		desc_size += sizeof(struct macb_dma_desc_64);
+	if (bp->hw_dma_cap & HW_DMA_CAP_PTP)
+		desc_size += sizeof(struct macb_dma_desc_ptp);
 #endif
-	return sizeof(struct macb_dma_desc);
+
+	return desc_size;
 }
 
 static unsigned int macb_adj_dma_desc_idx(struct macb *bp, unsigned int desc_idx)

-- 
2.50.1