[net-next v6 1/4] net: ethernet: mtk_eth_soc: support named IRQs

[Frank Wunderlich <linux@fw-web.de>]

From: Frank Wunderlich <frank-w@public-files.de>

Add named interrupts and keep index based fallback for existing
devicetrees.

Currently only rx and tx IRQs are defined to be used with mt7988, but
later extended with RSS/LRO support.

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
---
v6:
- change irq names from tx/rx to fe1/fe2 because reserved irqs
  are usable and not bound to specific function
- dropped Simons RB because of this
v5:
- fix typo in description
- add comments from previous patch #3 with changes suggested by simon

v2:
- move irqs loading part into own helper function
- reduce indentation
- place mtk_get_irqs helper before the irq_handler (note for simon)

net: mtk_eth_soc: change irq name back to fe1 + fe2
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 46 ++++++++++++++++-----
 1 file changed, 35 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index b38e4f2de674..c5deb8183afe 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -3336,6 +3336,37 @@ static void mtk_tx_timeout(struct net_device *dev, unsigned int txqueue)
 	schedule_work(&eth->pending_work);
 }
 
+static int mtk_get_irqs(struct platform_device *pdev, struct mtk_eth *eth)
+{
+	int i;
+
+	/* future SoCs beginning with MT7988 should use named IRQs in dts */
+	eth->irq[1] = platform_get_irq_byname(pdev, "fe1");
+	eth->irq[2] = platform_get_irq_byname(pdev, "fe2");
+	if (eth->irq[1] >= 0 && eth->irq[2] >= 0)
+		return 0;
+
+	/* legacy way:
+	 * On MTK_SHARED_INT SoCs (MT7621 + MT7628) the first IRQ is taken
+	 * from devicetree and used for both RX and TX - it is shared.
+	 * On SoCs with non-shared IRQs the first entry is not used,
+	 * the second is for TX, and the third is for RX.
+	 */
+	for (i = 0; i < 3; i++) {
+		if (MTK_HAS_CAPS(eth->soc->caps, MTK_SHARED_INT) && i > 0)
+			eth->irq[i] = eth->irq[0];
+		else
+			eth->irq[i] = platform_get_irq(pdev, i);
+
+		if (eth->irq[i] < 0) {
+			dev_err(&pdev->dev, "no IRQ%d resource found\n", i);
+			return -ENXIO;
+		}
+	}
+
+	return 0;
+}
+
 static irqreturn_t mtk_handle_irq_rx(int irq, void *_eth)
 {
 	struct mtk_eth *eth = _eth;
@@ -5105,17 +5136,10 @@ static int mtk_probe(struct platform_device *pdev)
 		}
 	}
 
-	for (i = 0; i < 3; i++) {
-		if (MTK_HAS_CAPS(eth->soc->caps, MTK_SHARED_INT) && i > 0)
-			eth->irq[i] = eth->irq[0];
-		else
-			eth->irq[i] = platform_get_irq(pdev, i);
-		if (eth->irq[i] < 0) {
-			dev_err(&pdev->dev, "no IRQ%d resource found\n", i);
-			err = -ENXIO;
-			goto err_wed_exit;
-		}
-	}
+	err = mtk_get_irqs(pdev, eth);
+	if (err)
+		goto err_wed_exit;
+
 	for (i = 0; i < ARRAY_SIZE(eth->clks); i++) {
 		eth->clks[i] = devm_clk_get(eth->dev,
 					    mtk_clks_source_name[i]);
-- 
2.43.0