From 3bc8e0aff23be0526af0dbc7973a8866a08d73f1 Mon Sep 17 00:00:00 2001
From: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Date: Thu, 22 Apr 2021 22:21:08 -0700
Subject: [PATCH] net: ethernet: mtk_eth_soc: use iopoll.h macro for DMA init

Replace a tight busy-wait loop without a pause with a standard
readx_poll_timeout_atomic routine with a 5 us poll period.

Tested by booting a MT7621 device to ensure the driver initializes
properly.

Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 29 +++++++++------------
 drivers/net/ethernet/mediatek/mtk_eth_soc.h |  2 +-
 2 files changed, 14 insertions(+), 17 deletions(-)

--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -2054,25 +2054,22 @@ static int mtk_set_features(struct net_d
 /* wait for DMA to finish whatever it is doing before we start using it again */
 static int mtk_dma_busy_wait(struct mtk_eth *eth)
 {
-	unsigned long t_start = jiffies;
+	unsigned int reg;
+	int ret;
+	u32 val;
 
-	while (1) {
-		if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA)) {
-			if (!(mtk_r32(eth, MTK_QDMA_GLO_CFG) &
-			      (MTK_RX_DMA_BUSY | MTK_TX_DMA_BUSY)))
-				return 0;
-		} else {
-			if (!(mtk_r32(eth, MTK_PDMA_GLO_CFG) &
-			      (MTK_RX_DMA_BUSY | MTK_TX_DMA_BUSY)))
-				return 0;
-		}
+	if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA))
+		reg = MTK_QDMA_GLO_CFG;
+	else
+		reg = MTK_PDMA_GLO_CFG;
 
-		if (time_after(jiffies, t_start + MTK_DMA_BUSY_TIMEOUT))
-			break;
-	}
+	ret = readx_poll_timeout_atomic(__raw_readl, eth->base + reg, val,
+					!(val & (MTK_RX_DMA_BUSY | MTK_TX_DMA_BUSY)),
+					5, MTK_DMA_BUSY_TIMEOUT_US);
+	if (ret)
+		dev_err(eth->dev, "DMA init timeout\n");
 
-	dev_err(eth->dev, "DMA init timeout\n");
-	return -1;
+	return ret;
 }
 
 static int mtk_dma_init(struct mtk_eth *eth)
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -213,7 +213,7 @@
 #define MTK_TX_DMA_BUSY		BIT(1)
 #define MTK_RX_DMA_EN		BIT(2)
 #define MTK_TX_DMA_EN		BIT(0)
-#define MTK_DMA_BUSY_TIMEOUT	HZ
+#define MTK_DMA_BUSY_TIMEOUT_US	1000000
 
 /* QDMA Reset Index Register */
 #define MTK_QDMA_RST_IDX	0x1A08
